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ARCTIC MARINE SCIENCE CURRICULUM
MODULE 3
LIVING ORGANISMS
STUDENT GUIDE
2001
Prepared for:
Fisheries and Oceans Canada
Northwest Territories Dept. of Education, Culture and Employment
Nunavut Department of Education
Yukon Department of Education
Prepared by:
AIMM North Heritage Tourism Consulting
with
Prairie Sea Services, Bufo Incorporated and Adrian Schimnowski
MODULE 3
STUDENT GUIDE
MODULE 3 - LIVING ORGANISMS
STUDENT GUIDE
TABLE OF CONTENTS
INTRODUCTION ............................................................................................. 1
1.1 CLASSIFICATION SYSTEMS ..................................................................... 2
1.2 KINGDOM MONERA ................................................................................ 9
1.3 KINGDOM PROTISTA .............................................................................12
1.4 KINGDOM PLANTAE ..............................................................................17
1.5 KINGDOM ANIMALIA .............................................................................18
GLOSSARY .................................................................................................57
MODULE 3 - LIVING ORGANISMS
STUDENT GUIDE
MODULE 3 – LIVING ORGANISMS
INTRODUCTION
In this module you will investigate the living
organisms that inhabit the Arctic region and the
importance of these organisms to the people that live
there.
The Inuit have prevailed over the centuries
because of their extraordinary ability to
draw sustenance from the vast lands and
frozen seas over which they have roamed
in a difficult struggle for survival. They
share these lands with many creatures. The
frigid climate and the absence of arable
soils render the land incapable of yielding
grains or fruits suitable for human
consumption. To meet basic needs for food
and warmth, Inuit have traditionally been
compelled to turn almost exclusively to
animals-whether fish, fowl or mammals.
This reliance has helped engender a deep
integration with nature. The Inuit hold a
profound relationship with fellow beings of
the Arctic and an abiding respect for them.
In the Inuit way of seeing the world, each
living thing has a soul and a spirit that
endures even after life has left the body.
The Inuit hunter is grateful for the food,
clothing and other necessities these
creatures provide. He seeks to protect their
spirits so that others will come and the hunt
can be renewed. Special rituals are
observed to show respect for the soul of a
fallen animal, for example, placing fresh
water, obtained from melted snow, in the
mouth of a slain seal to help slake its thirst.
Try This:
1. Invite Elders into the
classroom or interview Elders
in their home or on the land
to identify special rituals that
are used for particular
animals to show respect and
ensure successful future
hunts.
2. Why was it so important for
Aboriginal people to show
respect to the animals they
hunted?
3. Is it still important for hunters
to show respect for the
animals that are killed?
Explain your answer.
Source:
Seals and Nunavut:
Our Tradition, Our Future
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1.1
STUDENT GUIDE
CLASSIFICATION SYSTEMS
Describing, naming, and grouping the many
different kinds of living things on the earth and in
the waters of the earth has been both a necessity and
a pastime for centuries. Think of all the different
ways you can describe and group organisms. For
example, field guides, such as "Barrenland
Beauties", group organisms based on where they are
found. Hunters will also know what types of
organisms can be found where, at what type of year.
It is often useful to group organisms by what they
do. For example, Inuit describe certain species of
shrimp as the ocean's "cleaners" because they eat
any decaying matter.
Ecological Knowledge
The following information describes and example of
the Ecological Knowledge held by the Inuit.
Nunatuttiit are land creatures that breathe
but do not fly, such as caribou, fox, rabbit
and lemming. Puijiit are animals that
surface in the sea to breathe and are
layered thickly with fat. Polar bears occupy
a position between the two categories, for
they are not exclusively of the land nor of
the sea, but of both. Larger birds are
collectively termed tingmiat, the fliers. Many
varieties of fish are named, but there is no
generic term for fish. The term iqaluk is
often used to mean fish in general, but
usually by younger people. For our elders,
iqaluk is used to indicate Arctic char, but
other terms, such as tisuajuk, ivisarak and
nutilliajuk, are more specific.
We understand that all large marine and
land mammals, fish and birds that we
depend on for food are themselves
dependent on the many varieties of smaller
plants, animals and insects found on the
land and in the sea. Some of these have
specific names as well. A number of insects
are named: bee is iguta; spider, ausivaq;
"I am going to talk about two
things They have differences
between them. For instance there
are the puijiit, the bases of
human sustenance, the sea
animals. And there are nunatuttiit,
the planteating animals. I just
want to make it clear about the
differences, and also because I
need to be understood. Puijiit, the
sea animals, are what they are
called by the Inuit, those sea
animals that are fit for human
consumption. Then polar bears,
caribou, hares and foxes are
called pisutiit, walking animals."
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mosquito, qitturiak and butterfly,
takalikituak.
Our knowledge identifies these different
creatures, and it also identifies many other
factors that help us understand the
behavior of resources we depend on
directly for food and indirectly as the food of
our food. The relationship between living
things, and between the environment and
living things, contributes to a very complex
web of life. Our identification of these
relationships and of the complexity of the
web demonstrates our ecological
understanding.
"When we think of something or
discover a new fact, we also think
of all the interconnections
between that fact and everything
else. And so it is with our
science: it is going to be
connected to everything within
our culture. If scientists have
trouble with this idea, they should
take time to understand it better. I
think we have something
important to teach them that will
make them much better
researchers and help them solve
problems more easily."
Source:
Inuit Tapirisat
www.tapirisat.ca
The start of the scientific classification system began
with an early grouping of organisms on the basis of
structural similarities. The Greeks and Romans who
grouped plants and animals into basic categories
such as dogs, oaks and horses, etc. This method of
grouping into categories was expanded into a simple
classification system. Eventually, each unit of
classification was called a genus, the Latin word for
'group'. Seventeenth century European naturalists
made this system very complicated by giving plants
and animals descriptive Latin names, sometimes five
or six words long.
In the mid nineteenth century, a Swedish biologist
named Carolus Linnaeus simplified the problem of
categorizing life's diversity by assigning every
organism then known to science to a series of
increasingly specific groups, depending on the
number of structural traits shared by group members.
The science of classifying organisms is called
taxonomy. The hierarchy of taxonomic
classifications starts with the broad category of
Kingdom, then descends with ever-increasing
specificity as outlined in Figure 1.
Kingdom
Phylum
Class
Order
Family
Genus
Species
Figure 1: Taxonomic Classification
Hierarchy
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For many years, taxonomy was based on physical
structures such as the number and arrangement of
toes or the shape of the skull. In recent years,
however, a branch of taxonomy known as
phylogenetics has dramatically changed the way we
look at species, at families and at orders.
Phylogeneticists classify organisms through their
genetic similarity, as evidenced by DNA sequences.
As a result, the evolutionary relationships are better
understood, and new species may be recognized. For
example, some taxonomists no longer classify
crocodilians (alligators, crocodiles and their
relatives) as reptiles and instead link them to birds
and dinosaurs.
Figure 2 provides two examples of how the
scientific classification system works.
HUMAN
Taxonomic Level
Kingdom
Phylum
Class
Order
Family
Genus
Species
Taxonomic Level
Kingdom
Phylum
WHITE WHALE
Class
(Beluga)
Order
Family
Genus
Species
Example
Animalia
Chordata
Mammalia
Primates
Hominidae
Homo
sapiens
Example
Animalia
Chordata
Mammalia
Cetacea
Delphinidae
Delphinapterus
leucas
Figure 2: Scientific Classificaiton Breakdown for Human and Whales
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There are at least 30 million different species of
plants and animals alive today. Many of these have
no common name (e.g. beluga). When biologists and
scientists discuss an animal, they usually refer to the
scientific name which is identified by the genus and
species, to avoid any possible confusion; for
example the common name herring is used in the
Tuktoyaktuk for Coregonus autumnalis, in
Yellowknife for Coregonus artedii and in
Vancouver for Clupea harengus all three are
different species. Scientists only use a common
name if it is referenced to a scientific name.
Ε Check Your Understanding
Discuss the following questions with a classmate and then answer them in your
notebook. Be prepared to discuss these questions in class.
1. What are two reasons why scientists needed a classification system?
2. Why are there so many levels to the system?
3. Briefly describe a classification system similar to taxonomy.
4. List the taxonomic levels.
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Figure 3 summarizes the taxonomic classification
system. As you can see, there is a general separation
between the Prokaryotes and Eukaryotes. The
prokaryotes are among the simplest, most primitive
forms of life. In this type of cell, there are no cell
organelles as there are in the eukaryotes.
Figure 3: Taxonomic Classification
System
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OTHER WAYS TO LOOK AT LIVING THINGS IN THE
OCEAN
The study of oceans is so vast and complex that one
person cannot hope to become an expert on
everything. Marine biologists and oceanographers
often focus their studies on one part of the ocean. To
simplify terminology, scientists have agreed to give
certain names to the different parts of the ocean.
Figure 4 contains the names given – some of which
you will be familiar with. Bookmark this page so
you can refer back to it when a new term is
introduced and you need to see where it fits in the
total profile of the ocean.
Organisms found in the ocean can be grouped
according to three fundamental life styles:
planktonic, nektonic and benthic.
Figure 4: Ocean Zones
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Planktonic
Plankton are organisms that drift with the ocean
currents. Many such organisms have some ability to
move but usually only in a vertical direction.
Autotrophs that follow this drifting life style in the
upper layers of the ocean are called phytoplankton.
Planktonic heterotrophic organisms that depend on
external food supply are called zooplankton. Most of
the biomass of the earth is found adrift in the oceans
as plankton. Many of the nekton organisms and
almost all of the benthic organisms make their home
in the plankton community during their larval stages.
As adults, benthos sink to the bottom and nekton
begin to swim freely.
Nektonic
Nekton include all animals that can move
independently of ocean currents. Included are most
adult fish and squid, marine mammals, and most
marine reptiles. These animals are limited in their
movement by invisible barriers created by gradual
changes in temperature, salinity. Vertical range may
be determined by water pressure, temperature or
other factors.
Benthic
Benthic organisms live on or in the ocean bottom.
They may live in mud, sand, or buried shells. They
may also attach themselves to rocks or move over
the surface of the bottom.
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1.2
STUDENT GUIDE
KINGDOM MONERA
This Kingdom includes bacteria and the Blue -Green
Algae (cyanobacteria). The members of this
kingdom are prokaryotic which means that they are
the most primitive of all one-celled organisms. They
contain no nucleus nor do they contain mitochondria
or chloroplasts.
BACTERIA
Bacteria are found everywhere in the marine
environment including deep-sea vents, volcanic
vents, the Arctic and the Antarctic. Bacteria grow
best when they can attach to a substrate.
Consequently marine bacteria are more common in
bottom sediments than in the water column.
However in estuaries, such as the Mackenzie River
estuary, which contain a lot of suspended solids,
bacteria can also be abundant in the water column as
the bacteria can attach themselves to these
suspended particles. The taxonomy of marine
bacteria is poorly known. Scientists have found that
bacterial cells often change with their environment,
which makes classification difficult.
Figure 5 illustrates the ability of some bacteria to
change their classical shape of rods, spheres and
spirals. You will do an activity in the lab where you
will see the various shapes of bacteria.
There are fewer marine bacteria than terrestrial
forms but this does not lessen their importance to the
marine food chain. There are three groups of marine
bacteria: saprobic (decomposers),
autotrophic(producers), and pathogenic / parasitic.
Figure 5: Shapes of Marine Bacteria
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Saprobic bacteria are important in the decomposition
of organic matter. They reduce dead tissue, feces,
and other remains of marine organisms to the
inorganic compounds of CO2, nitrate (NO 3- ) , and
phosphate ( PO4 3- ). As decomposers, saprobic
bacteria are the key link in detritus-based food webs,
which are so important to benthic marine organisms.
An interesting characteristic is their ability to use
most organic molecules as a source of energy. They
have also been found to slowly degrade petroleum
products released into the environment from oil
spills or from community pollution.
Autotrophic or chemosynthetic bacteria are
important because they can produce complex
organic molecules where photosynthesis is not
possible due to the lack of light energy.
Pathogenic/parasitic bacteria in the marine
environment are not as well known as in the
terrestrial world. However, some diseases found in
marine mammals, fish, and invertebrates are caused
by bacterial infections.
BLUE-GREEN ALGAE
Blue-Green Algae are believed to be among the first
photosynthetic organisms on earth. Many species are
marine and can tolerate wide ranges of salinity and
temperature. They are found almost everywhere
including the least expected places like the hair of
polar bears!
In the Arctic marine environment, blue-green algae
are limited by low temperatures and occur only in
low abundance. Their occurrence is a biological
marker for areas where warm southern waters reach
during the summer.
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Ε
STUDENT GUIDE
Check Your Understanding
1. Look at the profile of the ocean and explain the difference between
benthic and pelagic organisms.
2. List the major kingdoms.
3. What is the difference between a prokaryote and a eukaryote cell?
4. Describe an importance characteristic of saprobic bacteria.
5. Theorize another use for saprobic bacteria.
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1.3
STUDENT GUIDE
KINGDOM PROTISTA
PHYTOPLANKTON
This kingdom and all others are eukaryotic which
means they have a full complement of cell
organelles with a nucleus that contains the genetic
material. Members of this kingdom include: diatoms,
dinoflagellates, algae and protists. They are
collectively called phytoplankton (drifting plant).
A diagram of a typical eukaryotic can be seen in
Figure 6.
Figure 6: Typical Eukaryotic Cell
The phytoplankton of the ocean are often referred to
as the 'pastures of the sea'. The role of phytoplankton
in capturing the sun's energy in the marine
environment is very important to all marine life.
They are mainly small unicellular (single-celled)
plants known as algae. Each planktonic cell is an
independent, photosynthesizing individual. They can
occur either as single cells or as long chains. At least
90% of the photosynthesis in the marine
environment is due to phytoplankton. The remaining
10% is from littoral (see the ocean profile for this
zone) and shallow water algae and sea grasses. The
phytoplankton at any given location is generally a
mixed population of species belonging to a number
of groups. Diatom (Figure 8) and dinoflagellates
(Figure 7) are two
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major groups of organisms belonging to the
phytoplankton.
Figure 7 is of a selection of dinoflagellates. They
usually have two whip-like appendages or flagella
that give the cells limited swimming movement. The
two organisms in the middle of the right diagram
produce toxic red tides and paralytic shellfish
poisoning.
Primarily diatoms and dinoflagellates dominate
Arctic marine phytoplankton.
Figure 7: Dinoglagellates
Stephanodiscus niagrae
A. valve view
B. girdle view
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ALGAE
Algae is the term used for marine and freshwater
plants, including most seaweeds. They can be singlecelled, colonial, or multi-celled, with chlorophyll but
not true roots, stems, leaves, and with no flowers or
seeds. There are three distinct types of eukaryotic
sea algae: green, brown and red. Each has its own
distinct structure and reproductive cycle.
Green algae can be quite small in relation to other
forms of algae. They appear in the shape of sheets or
tubules. Although growth in green algae is usually
vegetative, there is a well-defined sexual
reproductive cycle. Using the species Ulva we will
follow the cycle.
Figure 9 - Green Algae
The two stages illustrated in Figure 9, differ only in
the number of chromosomes in each cell. The
sporophyte stage is diploid (having a double set of
chromosome: 2n), The sporophyte produces spores
through meiosis at the margin of the blade. These are
released and grow up as a gametophyte. The
gametophyte stage is haploid (having a single set of
chromosomes: 1n ). The gametophyte releases the
male and female isogametes which fuse to produce a
2n zygote that develops into the sporophyte stage.
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Brown algae among the largest and most complex
algae grow to lengths of up to 50 m. This species
includes a number of large plants generally called
kelp. Most species of kelp can be divided into three
parts: holdfast, stipe and frond.
Many brown algae have floats, or pneumatocysts,
located either on the fronds or stipe. Pneumatocysts
are filled with gases that help the algae float.
Commonly these gases are those that are dissolved
in water like oxygen, nitrogen and carbon dioxide.
Reproduction in brown algae is characterized by
alternating generations. In some species like the one
shown, the haploid, or gametophyte generation is a
single cell. Only the sporophyte is multicellular.
Specialized cells on the frond called sporangia
produce flagellated microscopic zoospores. These
zoospores, which are haploid, swim to the bottom
and grow into the small gametophyte stage.
Brown algae occur on the Arctic Ocean bottom.
Many small invertebrates live among the blades of
kelp and “Devil’s apron’, a seaweed of big, flat
brown sheets. Initially attached to rocks, these
seaweeds are often torn loose by storms and drift to
the surface with numerous small animals attached to
them. They freeze into the ice and in spring melt first
because they are dark. In the pools around them you
may find the remains of creatures from the bottom
such as clams, sea urchins, sea stars and sometimes
the hollow shells of amphipods.
These gametophytes are either male or female.
The male gametophyte produces mobile sperm cells
that swim to the female that has already produced
nonmotile eggs. After fertilization, the diploid
zygote attaches to the bottom and grows into the
larger sporophyte stage.
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Red Algae are mostly filamentous or sheet-like
macro algae. Their name comes from the presence of
a red photosynthetic pigments that usually mask the
chlorophyll of green plants found on land. Most
species are marine and are found in the benthos
attached by a holdfast. There are no motile red algae
and even the reproductive stages cannot swim. Their
reproductive cycles involve the alternation of
generations like the other algae species but in
patterns that are often complex.
These open water areas are ideal habitat for
microorganisms at the bottom of the food chain (for
all trophic levels). In addition to the open water,
there is a steady supply of nutrients (especially
nitrogen and phosphorus) brought to the surface by
upwelling currents. Ice algae are one-celled plants
that live and breed in the pores in the underside of
the ice. Ice algae live on the underside of ice near
holes, cracks, leads, under thin ice and/or with or no
snow cover. Ice algae is common in first year ice.
They give the bottom of the ice a yellowish brown
colour and are grazed upon by zooplankton.
A special species of ice algae called Helosira forms
very long strands under the ice. These strands can be
a few meters in length although the algae is a
phytoplankton = 1 cell (only a few 1/10 of mm
length).
Ice algae is mainly made of diatoms that grow
between the ice crystals on the underside of sea ice.
The light that reaches the algae and the nutrients it
receives from the water below the ice determines the
abundance of ice algae. The amount of available
light is controlled mainly by the thickness of the
snow cover, whereas water currents and diffusion
control nutrient availability. At high abundance, the
bottom of the ice can turn dark greenish brown in
color. Ice algae are very important to productivity of
the Arctic Ocean by providing a kick-start to spring.
They allow the growing season or season of
maximum productivity to begin earlier than it would
otherwise. A community develops in association
with the ice algae which includes zooplankton, (in
particular amphipods and copepods), Arctic cod etc.
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1.4
KINGDOM PLANTAE
Plants are the primary source of food energy through
photosynthesis on land but in the marine world, that
responsibility has been left to the organisms that we
have already discussed. The explanation for this lies
in the functioning of the vascular system. Plants rely
on the evaporation of water from the leaf surface to
provide the force that draws water from the roots and
through the stems to the leaves. For plants that are
only partially submerged in seawater, such as
saltwater marshes, this evapotranspiration system
can still work, although these plants must use up a
lot of energy to desalinate the salty water coming
into their root system.
Salt marsh plants can stand only periodic
submergence in seawater and are found in the
intertidal zone between high tide level and low tide
level.
Ε
STUDENT GUIDE
Did You Know…
Much of the Arctic coastal area is
very inhospitable to plants as a
result of ice scouring and
exposure. But a few do make a
living there:
•
Sheltered beaches - seashore
starwort
•
Shingle or cobble beaches –
scurvy grass, sea lungwort
•
Sandy beaches - seapurslane
•
Beaches, barrier islands,
dunes - lyme grass
Check Your Understanding (sections 1.3 to 1.5)
1. What organisms are included as phytoplankton?
2. Diatoms and dinoflagellates are microorganisms. Sketch a food chain to
show their importance.
3. Sketch a diagram of a green algae to show its three basic structures.
4. What is the primary function of marine fungi?
5. What is the principal difference between land plants and marine plants?
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1.5
STUDENT GUIDE
KINGDOM ANIMALIA
ZOOPLANKTON
Let us first look at the smallest form of animals that
make up an important part of all food chains. This
group of organisms is referred to as zooplankton.
Most large epipelagic animals cannot feed directly
on the tiny phytoplankton. They rely on herbivores
that can. Of all the herbivores in the epipelagic zone,
zooplankton are far the most important. They belong
to almost every food chain in the ocean.
Zooplankton are weak swimmers – enough for them
to catch a floating phytoplankton – and are carried
around by the currents. By far the most abundant of
the zooplankton are protozoa.
Copepods are very small crustaceans and are usually
the largest component of the more visible
zooplankton. A sample of zooplankton collected
with a net can contain about 95% copepods.
In the Arctic and Antarctic, the euphausiids are often
the krill, usually Euphausia superba, occurring in
such large numbers that they provide the main food
for the giant baleen whales such as the bowhead
whale in the Arctic.
Figure 10 contains two types of copepod. The lower
form is found in the Arctic and the other in
temperate waters.
Figure 10: Copepods
The following account of whale growth in the Arctic
will show you why small organisms that we can
hardly see are so important to the North.
To illustrate the great productivity that occurs during
the short summer season in Polar Regions, consider
the growth rate of baby whales. The bowhead whale
is able to develop and support calves during a
gestation (development within the womb) of 13-14
months. The calves reach 4.3 metres in length and
weigh approximately 907 kilograms.
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By the end of the first year, the young whales grow
to 8 metres in length. This phenomenal growth rate
gives some indication of the great biomass of
copepods and krill that these large mammals feed
upon.
Epipelagic food webs tend to be long and complex
because they contain many species and different
trophic levels. The following is such an example of
this kind of food web.
INVERTEBRATES
Invertebrates dominate the animal kingdom. There
are about 30 phyla in the animal kingdom of which
all but one are invertebrates, and one major group,
the arthropods, consist of over a million species
(85% of all animal species). Arthropods are the most
abundant phylum on the planet and if you traveled to
the deepest ocean trenches, highest mountaintops or
could even swim in a geothermal pool you would
find a member of this phylum waiting to greet you.
As a group they are easy to recognize with their hard
outer cuticle, unique compound eyes, and a pair of
legs on each segment of the body that are grouped
into functional tagma.
Due to the incredible number of species, it has
always been a problem to identify them. We will
only discuss those groups that occur in the benthos
of the Arctic marine environment.
Few studies have been done on benthic invertebrates
in the Arctic because of the difficulties in doing so
and the lack of commercial potential. Benthic
invertebrates depend on the availability of plankton
and decaying organic material. Many are scavengers.
The most common benthic invertebrates are
amphipods. Amphipods are crustaceans, typically
ranging in size from 2 to 50 mm, although a few
may be larger. Amphipods are common in aquatic
ecosystems throughout many parts of the world,
inhabiting marine, brackish, and freshwater
environments. The order Amphipoda contains nearly
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7,000 described species. Some groups live their lives
attached to marine mammals. These whale-lice are
ectoparasites that cling firmly to, and feed on, the
skin of whales. Unlike other amphipods, whale-lice
cannot swim so once the juveniles leave the brood
chamber of the female they attach themselves close
by. Another example of an amphipod is sea lice.
Many fishermen will recognize these if they leave
their nets in too long.
A Typical Amphipod
Comb jellies or ctenophores are very abundant in the
Arctic. They have radial symmetry and have a
gelatinous body. They are carnivores with a great
appetite. Swarms of comb jellies may consume large
numbers of fish larvae. Many capture their prey
using two long tentacles armed with sticky cells
named colloblasts.
Other groups of invertebrates are present but are less
common and diverse:
•
•
•
Polychaetes are segmented worms and are
among the most common marine organisms.
They can be found living in the depths of the
ocean, floating free near the surface, or
burrowing in the mud and sand of the beach.
Some, such as Eunice gigantea, may reach
three meters long.
Polychaetes are known by many names:
lugworms, clam worms, bristleworms, fire
worms, etc., but all possess an array of
bristles on their many leg-like parapodia.
The name polychaete, in fact, means "many
bristles". The many common names reflect
the wide array of body forms found in this
group, unlike the related earthworms and
leeches which all have the same general
appearance. Many small polychaetes dwell in
the bottom ice.
Gastropod (also called univalves) are a type
of mollusk that have a single valve (a shell,
which is sometimes reduced or even absent)
and a muscular foot. There are over 90,000
Figure 11: A Typical Amphipod
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•
•
STUDENT GUIDE
species of gastropods worldwide, both in the
water and on land. Some gastropods include
snails, whelks, and slugs.
Brittle stars, sea urchins, sand dollars, sea
cucumbers, sea stars, basketstars and feather
stars are commonly found in the Arctic.
These and many other organisms make up
the Echinodermata, the largest phylum to
lack any freshwater or land representatives.
Most echinoderms have five-fold symmetry,
with rays or arms in fives, or multiples of
five. Echinoderms have a system of internal
water-filled canals, which in many
echinoderms form suckered "tube feet", with
which the animal may move or grip objects.
The decapod, 10 legs, crustaceans are
amongst the most familiar as they include the
lobsters, crab and shrimp that are often
harvested for food. Shrimp occur both in the
benthic Arctic environment as well as pelagic
and like most of its kind, are primarily
scavengers.
FISH
Fish are part of the kingdom Animalia. The phylum
to which they belong is chordata. Chordates have the
following characteristics:
• Central spinal cord
• Notochord or backbone
• Tail (at some stage of life)
• Muscle blocks
• Gill slits (at some stage of life)
Ask your teacher to show you diagrams of the
human stage where all these characteristics are
present. You probably didn't know you had gills and
a tail at one stage of your life!
There are two classes of fish that we will look at: the
bony fish called Osteichthyes and the cartilaginous
fish called Chondrichthyes. Both of these classes can
be found in the Arctic.
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Scientists believe that fish were the first vertebrates
to evolve. And from them all other forms of
vertebrate life developed. Unlike mammals and
birds, they have no lungs, taking oxygen from the
water directly into the blood stream by means of
gills. The hard flaps covering the gills are called the
operculum. Bony fish have an air bladder that is
used to regulate buoyancy. Scales are often but not
always present. For many species, scales can be used
to determine age by counting growth rings. We will
do a fish lab in which we will determine the age of
fish by examining their scales and the otolith – a
bone-like structure found in a fish’s inner ear.
Fish have an extremely well developed sense of
smell. They also have senses of sight, hearing and
taste. Their sense of touch is generally poor, except
in those fish that have barbels, which help locate
food by touch. They also have 'skin senses' such as
the lateral line system seen in many fishes. This is a
line of pores along each side of the body used for
detecting changes in pressure and temperature. Some
fish can also detect electromagnetic fields, a skill
that may be useful for finding prey, avoiding
predators, and for navigation.
The tuna fish shown in Figure 12 has a more
muscular body and a large powerful caudal fin for
increased speed.
Most fish have similar fin structure. The caudal fin
thrusts from side to side to propel the fish forward.
The dorsal fins prevent the fish from rolling as it
swims, and a ventral anal fin keeps the fish from
slipping sideways. Paired pectoral and pelvic fins act
to assist the fish in moving up or down, in turning
and in stopping.
The distribution and diversity of fishes is determined
by a number of conditions, including: temperature,
light, and salinity. Some species are benthic (bottom
-dwelling) while others are pelagic (swimming about
freely). Most fishes inhabit either freshwater or
seawater but some can live in both environments.
STUDENT GUIDE
Village Science
Over thirty years ago, right after
freeze-up, I helped Jack Ingatti
make a fish trap. We spent hours
splitting spruce for the fence,
chopping poles to support the
fence and many more hours
picking river ice to set the trap.
The first time we checked the fish
trap was an eye-opener.
Hundreds of lush (burbot) flopped
on the ice until the cold air
silenced their efforts. Every day
the trap produced a harvest for
the village.
One of my partners and I had a
dog team that was a composite of
all the rejects in the village-dogs
people didn't want to feed and
didn't want to shoot. They were
slow but adequate for our needs.
The old-timers told us not to feed
fresh lush to our dogs but to
freeze them for several nights
first. We thought about it and
decided that they were giving us
some superstition because we
could see that the lush were fat
and good dog feed. When it was
our turn to check the fish trap, the
dogs agreed with us as they ate
the fresh lush on the spot. We
didn't say anything, not wanting
to hurt people's feelings by
exposing the local superstition.
Within two weeks our dogs were
totally lifeless. We had to rest
them halfway to the store and it
was only two miles from the
village. Occasionally, someone
mumbled, "fresh lush." We didn't
make the connection for quite a
while.
(continued on next page)
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Figure 12: Arctic Charr
(…cont’d)
Fish that live in salt water but migrate up rivers to
spawn are called anadromous. There has been much
information collected about freshwater fishes that
live in the Northwest Territories, Yukon and
Nunavut but marine fishes are less well known. This
is generally because fresh water fishes are more
easily accessible to catch and study.
Figure 13 is the anatomy of a bony fish showing its
main organs.
We fed our dogs tremendous
amounts of dog feed, but they
remained skinny and lazy.
Finally, the tapeworms started
dangling from the dogs' posterior
and we got it. Fresh lush have
tapeworms! If we had frozen or
cooked the lush, our dogs could
have made it to the store without
a break halfway. Superstition?
Hardly. That was science.
Village Science
Sharing Our Pathways
Vol. 4, Issue 3
Summer 1999
by Alan Dick
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Anadromous Fish
This characteristic of some fish is a remarkable
example of animal adaptation to their life style and
the environment. The following information on
anadromous fish is taken from a presentation made
by Dr. Jim Reist at Oceans Day 1996 in Churchill,
Manitoba.
Most fish occupy either freshwater (e.g. lakes,
rivers) or marine (e.g. oceans) habitats at all times of
their life.
Some examples of freshwater fish are:
• Walleye Stizostedion vitreum
• Burbot Lota Iota
• Northern Pike Esox lucius
Some examples of marine fish are:
• Capelin Mallotus villosus
• Arctic Cod Boreogadus saida
However, some fish switch between freshwater and
marine habitats at different times of their life. These
are called diadromous fish (from the Latin di = two,
and drorn = to run). There are about 20,000 species
of fish and about 160 of these (0.80 %) exhibit
diadromy.
Diadromous Fish
Diadromous fish can be grouped into three types:
1. Anadramous (ana = up & drom = to run)
These fish migrate to the sea as sexually
immature fish and then migrate back to
freshwater to breed. For example: Pacific
salmon Oncorhynchus spp and Arctic char
Salvelinus alpinus. Most char return to
freshwater every year not always for
spawning, but to spend the winter.
2. Catadromous (cata = down & drom = to
nm):These fish migrate to freshwater as
sexually immature fish and then migrate to
the seawater as adults to breed. For example:
American eel Anguilla rostrata.
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3. Amphidromous (amphi = both & drom = to
run)
These fish migrate between freshwater and
sea water for purposes other than breeding.
For example: some of the southern
hemisphere fishes.
In the Arctic, the only diadromous fish we observe
are anadromous species.
Marine water does not freeze until about -1 .80C.
Fish freeze at 00C. Therefore, to survive in cold
Arctic waters, the fish must have anti-freeze in its
tissues. Arctic anadromous fish do not have this
adaptation therefore they must leave the sea every
fall. We see movement back into freshwater as an
upstream migration of large numbers of fish of many
sizes, ages, and maturities.
Some populations of Arctic char remain in
freshwater all their lives, but most are anadromous.
Within most populations of Arctic char, some fish
become adult without ever going to sea. The further
north, the greater the likelihood that the char
population never goes to sea.
Ε
Check Your Understanding
Discuss the following questions with a classmate and then answer them in your
notebook. Be prepared to discuss these questions in class.
1. It is possible for fish to drown. Speculate on the conditions that would
make this happen.
2. What structures in fishes enable them to adapt to their environment?
3. How do scientists determine the age of fishes?
4. Explain why it is necessary that anadromous fishes return to fresh water
for the winter.
5. Using a map identify areas that the class members have caught
anadromous fish.
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STUDENT GUIDE
Figure 13: Anatomy of a Fish
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STUDENT GUIDE
Village Science: A Fish Story
By the time they arrive in the
headwaters, male dog salmon have
large teeth that become badly
enmeshed in a net. I spent hours and
hours carefully extracting them, trying
not to tear the net.
I told the old man about my
frustrations. "You have to know how,"
was all he said.
A few days later, I was very tired,
having worked at a mine all day and
having fished all night. I spent more
time wearily taking fish out of the net
than I did with the net in the water.
I always keep a wooden club in the
boat to dispatch the livelier fish so
they don't flop and tangle the net
once it is hauled into the boat. I took
the club and angrily pounded the dog
salmon's teeth in abject frustration.
To my utter amazement, the teeth
easily fell off the jaw, and the net was
released. Within minutes, club in
hand, I removed the rest of the fish
from the net.
The next morning I told the old man
of my discovery.
He said, "That's how."
Sharing Our Pathways
Vol. 3: Issue 4
Sept/Oct 1998
by Alan Dick
Ε
Check Your Understanding
1. Why didn't the old man just explain how to free the fish more easily?
2. Have you ever had a similar experience with learning a new thing? Share the
experience with a classmate.
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Biological Importance of Arctic Cod
Like other marine environments, Arctic waters
support complex ecosystems of organisms
(including humans) that are connected by food
chains. The Arctic is different from more temperate
environments because there is less diversification of
species as well as a lower level of productivity. The
loss of a single species might seriously disrupt the
food chain, resulting in severe changes at all levels
of the chain. The loss of the Arctic cod in northern
areas by over fishing, from disease, from an
imbalance in the ecology or from all of these factors
would be serious as it is an important food in the diet
of many species of marine mammals, sea birds other
fish and humans.
Narwhals, for example, feed on predominantly
Arctic cod. The remains of as many as 64 Arctic cod
have been found in a single narwhal stomach.
Belugas and ringed seals also feed on this fish.
Seabirds, especially murres, depend heavily on
Arctic cod as a source of food.
In one study, it was estimated that over a 35-day
period, at least 1.4 million Arctic cod were eaten by
a line of seabirds stationed along the edge of 125 km
of fast ice. Arctic cod have still other predators.
Atlantic cod have been reported feeding on large
numbers of Arctic cod off northeastern
Newfoundland. Arctic char, Greenland halibut and
Atlantic salmon also feed on Arctic cod at various
times. And changes in the abundance of the different
species in only one situation that could change the
Arctic ecosystem. While there is always change in
any environment, some changes can be catastrophic
for some species. Natural cycles can be easily
displaced by biotic and abiotic changes such as
temperature, pollutants, increased shipping,
increased eco-tourism, the establishment of new
communities, commercial fishing, etc.
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GENERALIZED LIFE CYCLE OF AN ANADROMOUS FISH
ARCTIC CHAR
Figure 14
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ARCTIC MARINE MAMMALS
Traditionally, few cultures in the world were more
dependent on the animals of the sea than the Inuit. In
a land where resources were often scarce, the
Arctic seas with their vast populations of fish and
marine mammals provided the raw materials that
helped Inuit society survive in one of the world's
harshest climates. Even today, as massive material
changes continue to reshape Aboriginal society, the
people use marine mammals as important sources of
food, clothing, and increasingly, revenue in the from
of whalebone sculptures.
WHALES
The largest group of marine mammals is the
cetaceans (order Cetacea), the whales, dolphins and
porpoises. Of all marine mammals, the cetaceans
have made the most complete transition to aquatic
life. While most other marine mammals return to
land at least part of the time, cetaceans spend their
entire lives in the water. Their bodies are streamlined
and look remarkably fish-like.
Though they resemble fishes, cetaceans’ breath air
and will drown if trapped below the surface. They
are "warm-blooded,” have hair (though not much)
and produce milk for their young.
Cetaceans have a pair of front flippers, but the rear
pair of limbs has all but disappeared. The rear limbs
are present during the embryo stage but fail to
develop. Like fishes, many cetaceans have a dorsal
fin although it is often small. The muscular tail ends
in a pair of fin-like, horizontal flukes. Blubber
provides insulation and buoyancy. Cetacean nostrils
differ from those of other mammals. Rather than
being on the front of the head, they are on the top,
forming a single or double opening called the
blowhole.
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There are about 90 species of cetaceans, all of which
are marine except for five species of freshwater
dolphins. Cetaceans are divided into two groups:
(1) the toothless, filter feeders, that include the
bowhead
(2) the toothed, carnivores, a group that includes
the narwhal and beluga.
The toothless whales are better known as baleen
whales. Instead of teeth they have rows of flexible,
fibrous plates named baleen. Baleen is made of the
same material as our hair and nails. The inner edge
of each plate consists of hair-like bristles that
overlap and form a dense mat in the roof of the
mouth. The whale filter feeds by taking a mouthful
of water and then squeezing it out through the
bristles.
Baleen whales are not only the largest whales but
they are the largest animals that have ever lived on
the earth. There are 11 species of these majestic
creatures. They were once common in all the oceans,
but commercial over-hunting has brought many
species to the edge of extinction. Figure 15 provides
a look at the process by which a baleen whale
(bowhead) feeds.
Figure 15: Baleen Feeding Apparatus
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Belugas, narwhals, and bowheads are the three true
Arctic whales, although others are occasionally
spotted here in summer. Of the three Arctic whales,
belugas are the most numerous and widely
distributed. More than 60,000 and perhaps as many
as 100,000 live in the Arctic and the sub-arctic.
The Bowhead whale - Balaena mysticetus (arviq )
belongs to the right whale family, which received its
name in early whaling days. Being slow swimmers
and floating (rather than sinking ) when killed, as
well as providing a large amount of oil, they were
the " right " whales to hunt.
Figure 16: Bowhead Whale
Bowhead whales have very large heads compared to
their body size. This is because they have the longest
baleen of any living species reaching up to 4 m.
Bowheads may grow up to 20 m long and weigh
about 50 tonnes. They are dark black or bluish gray
in colour with a pale throat and underbelly.
Bowhead whales have been observed to feed
cooperatively in U-shaped groups taking advantage
of dense gatherings of invertebrates. Breaching and
leaping is also a common site.
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This species is the only baleen whale to inhabit polar
waters year round. In summer they are found in
Lancaster Sound, Davis Strait and northern Hudson
Bay. They winter in the loose ice or open water of
Greenland, and may venture as far south as northern
Labrador. They are not restricted to ice-free areas as
they can use their heads and bodies to push through
half a meter or more of solid ice.
Most bowhead whales live in the Bering, Chukchi
and Beaufort Seas along areas of pack ice. The
bowhead has been designated an endangered species
in both the eastern and western Arctic. Eastern
Arctic populations are estimated to include only 700
individuals, while the western population totals 8200
individuals.
Bowhead whales exhibit sexual dimorphism, with
females being larger than males. Unlike its close
relative the right whale, this rather rotund creature
has a smooth skin, with no callosities and supports
the longest baleen of any whalebone cetacean. They
are thought to be the world's oldest mammals with
some individuals living for at least more than 100
years as evidenced by the presence of 19th century
whaling harpoons found in their flesh.
The bowhead whale is both a surface skim-feeder, a
bottom-feeder and a water column feeder. It
consumes krill, amphipods (tiny shrimp-like
crustaceans) and copepods (tiny planktonic
crustaceans).
The bowhead inhabits Arctic waters, where pack ice
occasionally causes them to get trapped, or stranded.
The bowhead ordinarily overcomes these challenges
by being able to hold its breath for up to an hour,
and by being able to fracture ice up to 12 inches
thick to create breathing holes! Other whales that
travel in heavy ice-choked waters, such as the
beluga, are often found associated with bowheads as
they take advantage the larger whales’ breathing
holes.
STUDENT GUIDE
Did You Know …
Bowheads feed on:
iglirait/copepods… …they feed
on them by opening their mouths
and waiting, the mouth is full of
suqqaw/baleen and they are just
like hair… (in this way) the
bowhead collects its food; I guess
when they feel that they have
collected enough (on the hairy
fringes of the baleen) then they
close their mouths and eat it.
…the tips of the baleen are quite
hairy, and they stand up like teeth
all the way to the back of the
mouth…
Nauja Tassugat,
Clyde River
Did You Know …
Their food, the krill or the
copepods, when they are more
plentiful during some springs and
summers, the whales are around
in greater numbers, and in some
summers they are less; so people
would know that there are more
bowhead whales if they have
seen a lot more krill or copepods.
Jacobie Panipak,
Clyde River
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Pack ice is not the only hazard that the bowhead
whale faces. Because of its slow speed and nonaggressive behavior, young bowhead may be
attacked by killer whales.
In the past humans have greatly affected bowhead
populations. The whaling industry brought the
bowhead whale to the brink of extinction. Inuit still
hunt the bowhead, but the harvest is tightly
controlled.
Bowheads mature at 4 years of age and mate from
April to June. The gestation period is 12 months and
calves are born in April or May. Nursing lasts for a
year with additional births occurring every 2 years.
The behaviour of the bowhead whale is hard to study
because of the harsh environment that it inhabits.
Observations suggest that although migratory, their
movements are dictated by the seasonal advance and
retreat of ice. Bowheads typically travel alone, or in
groups of no more than six individuals. During
migration, the whales segregate themselves
according to age and sex. The bowhead is a slow
moving whale, commonly travelling at speeds of 3-4
knots, although when in flight, speeds of 7-9 knots
may be reached. It is not aggressive and often shows
curiosity toward small boats.
Little is known of bowhead whale reproduction. It is
thought that mating occurs from February to March
and gestation takes about 13 to 14 months.
These gentle giants were hunted by European
commercial hunters to near extinction in the 1800s
and early 1900s. To this day, their populations in the
eastern Arctic remains dangerously low, thus their
endangered status. There were once more than
11,000 bowheads in these waters. Today, most
biologists agree there are no more than 1,000.
The Beluga Whale- Delphinapterus leucas
(qinalugaq or qilalugaq ) stands out conspicuously
in dark waters. Belugas are circumpolar in their
distribution. They are found in Arctic and Subarctic
waters along the northern coasts of Canada, Alaska,
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Russia, Norway and Greenland. It is estimated that
between 40,000 and 60,000 belugas live in Canadian
waters.
Sexual maturity occurs at 8 years of age in males
and 5 years in females. Mating takes place in AprilMay. The mating system remains unknown but there
are indications that males are polygamous, breeding
with several females. Gestation lasts for 14.5
months and birth occurs in May and June. The
gestation period and the lactation period of some
18 months results in females only being able to
produce young approximately every 3 years.
Belugas belong to the suborder of toothed whales
(Odontoceti) and, together with narwhal, make up
the family Monodontidae. The beluga is an
opportunistic feeder with a diverse diet. Food items
very according to seasonal availability and consist of
many fish species, such as capelin, Arctic cod, and
herring, but also invertebrates such as shrimp, squid
and marine worms. As with most marine mammals,
there is a seasonal change in the storage of blubber
reserves. During their summer return to estuaries,
they do not appear to eat at all.
Belugas have a well-developed sense of hearing and
refined echolocation. They are also a very vocal
species emitting not only echolocation clicks but a
wide variety of modulated whistles which probably
serve in social communication. Congregating in
large numbers in the same area every summer, these
small-toothed whales are also the most gregarious
and most vocal of the Arctic whales, spending hours
rollicking in shallow waters, chirping, trilling, and
clicking to one another in apparent delight. Early
whalers actually dubbed them " sea canaries ". Their
ability to discriminate using echolocation appears to
be superior to the much-studied oceanic bottlenose
dolphin and is probably related to their navigation in
ice-filled winter habitats and their use of shallow
water in the summer.
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CONTAMINANTS
There is evidence of significant decline in both
PCBs and DDT in some marine mammals in the last
10 years. Yet, because of the high consumption of
marine mammals fat by Aboriginal people, there is a
concern about the effect of PCBs on human health.
The flooding of large amounts of land by the
development of future hydroelectric projects could
also result in significant amounts of methyl mercury
being transported to the coastal marine environment.
The following account of contamination by toxic
substances comes from the Proceedings of the
Workshop on Traditional and Contemporary
Knowledge of Nunavik Belugas, held in November
1994 at the Maurice Lamontagne Institute (Quebec).
A presentation was made on the sources
of contaminants in belugas, trends in
their concentrations, and their biological
consequences for humans and animals.
The principal heavy metals of concern in
Arctic mammals are mercury, cadmium,
lead, and arsenic. The man-made
chlorinated organics include PCBs, DDT,
toxaphene, chlordane, endosultphins,
and lindane. The hydrocarbons recorded
in Arctic mammals include PAHs and
alkane, while radionuclides include
cesium, strontium, plutonium, lead, and
polonium. The most important source of
hydrocarbons and radionuclides in the
Canadian Arctic may be ocean dumping
off the coast of the former Soviet Union.
The Canadian Arctic receives high
concentrations of heavy metals and
chlorinated organics, especially in winter,
primarily from atmospheric
transportation. These chemicals travel to
the Canadian Arctic, principally in the
form of gas or dust, and they can enter
marine and freshwater ecosystems and
travel through the food web, eventually
reaching marine mammals and the
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humans who eat them. Mercury
concentrations in the muscle and liver
tissues of belugas from different areas is
increasing. Belugas from eastern
Hudson Bay have highest concentration
of mercury in liver tissue.
Because of its hydroelectric
developments, the La Grande River
might be an important source of
contaminants in the foods consumed by
Inuit, since the current in eastern Hudson
Bay flows from south to north.
TECHNOLOGY’S IMPACTS
During a study of Inuit knowledge of the Southeast
Baffin Beluga the impact of technology on eastern
beluga populations was noted:
•
Since 1960's, when motorized boats were
first introduced to the North and they began
to be used for hunting whales, changes in
their behaviour have been observed. Hunters
chasing whales along the floe-edge with
snowmobiles has also affected their
behaviour.
•
Initially, whales were curious about the
noise. Today whales (who can hear from
great distances) avoid areas where motorized
boats are heard.
•
Whales are now scattered in areas where they
were once densely concentrated.
•
Whales detour by great distances and have
been known to travel within ice packs to
avoid hunters.
•
At the floe edge the behaviour has changed.
They no longer stay close to the ice when
feeding nor do they float still after feeding.
Many whales have learned to avoid hunters
at the floe-edge.
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•
STUDENT GUIDE
Elders in Pangnirtung have noticed a slight
decrease in the thickness of the whales' fat
and suspect this is due to whales needing to
travel faster and farther to avoid motorized
boats.
Source:
Final Report on A Study of
Inuit Knowledge of the Southeast Baffin Beluga,
Nunavut Wildlife Management Board, 1998.
Ε
Check Your Understanding
1. Summarize the impacts that technology has had on the behaviour and
health of beluga whales.
2. Identify and describe other ways that technology has impacted on hunting
methods, and possible implications of these changes.
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In order to deal with the changing nature of the hunt,
elders have recommended that a set of Hunters
Guidelines be established. These would help address
concerns related to the current competitiveness
amongst hunters because of quotas and help in the
renewal of traditional hunting methods. The
guidelines for hunting Belugas would ensure hunters
use the right equipment, use nets properly, butcher
whales properly, make safety a priority, use the
proper calibre rifles, use proper harpoons and floats,
practice proper hunting techniques, etc. Other topics
suggested as guidelines include:
1) distribution of catch (traditional distribution
methods),
2) chasing of whales, including steering of
whales,
3) safe hunting practices,
4) hunt leaders,
5) traditional laws, i.e. leaders to take first shot,
etc.
The Narwhal - Monodon monoceros (tuugaalik or
allanguaq ), the mysterious unicorn of the sea, also
boasts significant Nunavut populations, though its
range is more restricted that the beluga. The majority
of narwhals winter in northern Davis Strait and
southern Baffin Bay. Toward the end of June they
head for the fertile waters of Lancaster Sound and
the deep bays and fiords of northern Baffin Island
and beyond. A distinct population spends the winter
in Hudson Strait, moving into northwestern Hudson
Bay in spring.
Narwhals average four meters in length and weigh
nearly two tonnes. This species is remarkable for its
ivory tusk that twists from its upper jaw like the
overgrown tooth that it is. While narwhal belong
with the toothed whales, its small, narrow mouth is
toothless and the only two adult teeth it has are in
the upper right and left sides of the jaw, either
embedded in the jaw or, in males, extending out as a
tusk. Narwhal produce clicks and other sounds
though not as diverse a repertoire as beluga.
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Hundreds of years ago, reports of the existence of
unicorns were told by imaginative European
whalers.
The large majority of tusked narwhals are male,
although females occasionally grow them as well.
The purpose of this tusk is still unknown, although
different theories have been presented for centuries.
Most often, the tusk is used in displays of aggressive
behavior. Scientists believe that they may be used to
determine social rank, much like the antlers of a
moose.
The following information is from the Final Report
of the Inuit Bowhead Knowledge Study, Nunavut,
March 2000
The Inuit were convinced that wildlife populations
would remain healthy and abundant only if they
were harvested and treated with respect. Species that
are harvested in a disrespectful manner, or not
harvested at all (a sign of disrespect), may decline in
numbers or disappear altogether. Arguing and
fighting over wildlife, or talking badly about wildlife
in any way, are considered as being offensive to the
wildlife; this also includes harming, mistreating, and
abusing wildlife, or causing wildlife to suffer. Such
displays of disrespect may also lead to the
disappearance of wildlife.
It was also stipulated that harvested animals must be
utilized to the maximum extent possible, with
minimal waste; this is another means of respecting
wildlife. In the Inuit traditional way of living,
everything was utilized and nothing was thrown
away. Anything from the animal that was left over
would be cached for later use, and Inuit would
harvest only what they needed.
Failure to share wildlife with other members of the
community also constituted disrespectful treatment
of wildlife. Sharing of food is one of the basic and
vital foundations of Inuit society. Harvested wildlife
must be shared with family and community.
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Ε
STUDENT GUIDE
Check Your Understanding
1. Why do you think whale stories attract the interest of the media?
2. Describe the process by which a baleen whale collects food.
3. Research more about echolocation.
4. How do scientists arrive at the conclusion that whales are very social
animals?
SEALS, SEA LIONS AND WALRUSES
Seals and other related forms are marine mammals
that have paddle-shaped flippers for swimming, but
still need to return to land or ice at regular intervals.
They belong to the Order Pinnipedia, which means
“wing-foot.” Pinnipeds are predators, feeding mostly
on fish, squid and other invertebrates.
Most pinnipeds live in cold water. To keep warm
they have a thick layer of blubber like whales. They
also have bristly hair for added protection against the
cold. Many of them are quite large, which helps
conserve body heat because large animals have less
surface area for their size and therefore lose less
body heat.
The largest group of pinnipeds is the “true” seals
(family Phocidae) that are characterized by having
rear flippers that cannot be rotated forward. On land
they must move by pulling themselves along with
their front flippers. However, they are powerful
swimmers propelled by strokes of their rear flippers.
There are three families of Pinnipeds: Phocidae or
true seals as they are called, Otariidae which
included fur seals and sea lions (these can rotate
their back flippers and are very agile on land), and
Odobenidae or the walrus. Seals are hunted for their
skin, meat, and for the oil extracted from their
blubber.
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Five species of true seals are found in the Arctic
Ocean: ringed seal (Phoca hispida), harp seal
(Phoca groenlandica), bearded seal Erignathus
barbatus, harbour seal (Phoca vitulina), and hooded
seal (Cystophora cristato). However, the most
numerous are the ringed, harp, and bearded seals.
The Ringed Seal (Phoca hispida) is the most
abundant, widespread and important seal to the
socio-economy of many Arctic communities. The
common name refers to the circular markings on the
back of the adult. The scientific name refers to the
seal's bristly coat. Traditionally, this seal was the
main diet of the Inuit; its skin was used as clothing,
its blubber fuelled the soapstone lamps, qulliit, that
provided both light and warmth, and its intestines - a
delicacy to Inuit - were also used as containers and
igloo windows. The skin was made into the upper
parts of boots and clothing. While the animal is no
longer used to this extent today, the ringed seal is
still an important food source for the people living
along the Arctic coast, who also use the skin for
boots and mitts, and, less frequently, for parkas,
pants, and artwork.
A wide array of Inuit names describes their various
age classes, sex and condition. Some of these
include: "netsiak" (white coat), "netsiavinerk" (silver
jar), "netsilak" (adult), and "tiggak" (breeding male).
The name, Bearded Seal (Erignathus barbatus),
refers to its obvious moustache of long, white
whiskers. The alternate name of " square-flipper"
describes the shape of its front limbs. In Inuktitut, it
is called "ugjuk". Lacking distinctive coloration, the
pelt is dark gray on the back and lighter gray on the
belly. The sexes are similar in colour. An annual
molt occurs between March and August. Annual
growth rings in the teeth and fore claws indicate age.
The oldest seal that had been found was 31 years
old. This seal is one of the largest seals found in the
Northwest Territories. The average weight of adults
is 250 kg and the length averages 235 cm. The
blubber and hide layers account for 29 to 39 percent
of its weight. There are about 300,000 bearded
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seals in Canada. They are permanent residents of the
Arctic and are generally found as solitary individuals
in areas associated with moving pack ice, such as
leads and polynyas, however, they can maintain
breathing holes in areas of thin ice by breaking it
with their heads. Their diet consists of benthic
(bottom dwelling ) organisms found in the shallower
waters of the continental shelf. These include
worms, clams, crabs and fish, such as Arctic cod,
sculpin and flounder. Feeding dives as deep as 220
m have been reported.
An undisturbed seal swims with its head and back
above the water. When sleeping, it floats vertically.
The senses of sight and hearing are good while its
ability to smell is only fair. They sing long musical
underwater songs. Singing activity peaks in April
and May. Bearded seals have a large variety of songs
that form part of a complex social structure that is
not well understood. It may be related to claims of
territory and breeding. Mating occurs in mid-May
with a delayed implantation of two months resulting
in a total gestation period of 11 months and an active
gestation period of 9 months.
A single pup is born on the ice at the end of April to
early May. Bearded seals are the only northern seals
with four mammae rather than two. The mother-pup
bond is strong during the relatively short 12 to 18
days of the nursing period a recent study in
Svalbaard suggests the lactation period may be
longer – approximately 24 days. The pups are then
left on their own. A female may give birth every one
or two years. Sexual maturity is attained as six years
of age.
Bearded seals have always been important to the
Inuit of the Arctic. The tough, flexible hide is valued
for general uses like lines, traces, kayak coverings,
and kamik (boot) soles. The meat is suitable for
human and dog food: however, the liver may contain
toxic levels of vitamin A and accumulated residues
of mercury, DDT, DDE and dieldrin. The
roundworm Trichinella may be transmitted to people
who eat raw or frozen bearded seal meat.
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The Harp Seal (Phoca groenlandica) is one of
Canada's most controversial wildlife species. A
commercial hunt used to be conducted in the Gulf of
St. Lawrence in March before the seals migrated
north. This hunt focused largely on "white coats” –
newborn seals. Emotional campaigns promoted by
animal right groups brought an end to this hunt in
the 1980s. These groups claimed that the hunt was
inhumane and that the seals were declining in
numbers. Due to lobbying in 1983, the European
Economic Community banned the import of harp
and hooded sealskins. Though aimed at stopping the
killing of seal pups by Newfoundlanders, it also had
a damaging effect on the market for Inuit seals.
Slightly larger than the ringed seal, harp seals go
through a series of coats with different patterns
beginning with the white coat pup and ending with
the adult coat which is distinguished by the black,
harp-shaped saddle on their backs. These seals have
never been as vital to Inuit as ringed seals mainly
because they don't over-winter in the Arctic and also
because they were harder to capture. About 500,000
of them summer in Nunavut, migrating north when
the sea ice finally breaks up in the spring. They
return south to warmer waters with the coming of
autumn.
Inuit in the Hudson Bay Bioregion call the harp seal
qairulik This species has a fondness for porpoising
and frolicking in Arctic waters. They are found
mostly in the eastern part of the territory, ranging
throughout Foxe Basin, northern and eastern Hudson
Bay, Hudson and Davis straits, and the northern
parts of Baffin Bay as well as Lancaster Sound.
Walrus Odobenus rosmarus aiviq can often be
found packed like sardines on ice floes. On land
these massive animals (adult males can grow to 3.5
meters and 1,400 kg ) appear clumsy and move
about with great difficulty but in the water they are
masterful swimmers.
Walruses dine primarily on clams, using their
sensitive whiskers to detect the mollusks on the sea
floor. An adult walrus may eat as many as 3,000
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clams in a day, although they also eat other bottomdwelling creatures such as fish, crabs, and sea
cucumbers. There are reports that some old bulls will
kill ringed seals. Because they rarely dive deeper
than 75 m, walruses stay in or near shallow waters.
The most distinguishing feature of both males and
females of this species is its tremendous overbite.
Despite their Latin name odobenidae ("those that
walk with their teeth"), walruses do not use their
teeth for walking. In fact their tusks are used for
feeding, as a symbol of dominance or social rank
and occasionally to help lift themselves from the
water. In the Canadian Arctic, Atlantic walruses are
only found in the Hudson Bay area, the waters
around Baffin Island and the High Arctic. The much
larger Pacific walrus is found in Alaskan waters and
only occasionally is see in the Canadian portion of
the Beaufort Sea.
Ε
Check Your Understanding
1. What kind of seals do you have in your community? Estimate how many
there are. How has this number changed over the last 10 years?
2. What are the traditional names for the seals in your community?
3. How important to your community are seals today?
4. Speculate why nature delays the implantation of the embryo in the uterus
of ringed and Bearded seal.
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Polar bears Ursus maritimus Nanuq – are the
largest of all bears. Females generally weigh up to
300 kg whereas males can attain weights of 450 600 kg and lengths of 2.5 - 3.5 m from nose to tail.
This species is the most carnivorous of all bears.
More than 90% of their diet is seal, most of which is
ringed seal (70 %) with the remainder being bearded
seal. Occasionally, walrus, beluga and narwhal are
eaten, although these species are rarely killed by
bears, but rather are found as carrion along the
shore.
Polar bears range throughout the Arctic and
subarctic from the permanent ice pack of the Arctic
Ocean to southern James Bay. In summer, they seek
out areas of permanent ice, drift about on ice flows,
or come ashore at traditional retreats.
To avoid overheating, they are less active during the
warmer summer. They prey on birds and rodents,
consume vegetation, and scavenge the beaches.
When the sea ice forms again, they move on to it to
resume hunting seals. Unlike other species of bears,
only pregnant females den up during the winter.
Mating occurs in spring, but the embryo does not
begin to develop until September. In November or
December, the female excavates a snow den, often
on a south-facing hill near the coast. Some of the
best-known denning areas are southern Banks Island,
Simpson Peninsula, Southampton Island, Yukon
coast and eastern Baffin Island.
Cubs, usually twins, are born sometime between late
November and January. In March or April they leave
their dens and usually accompany their mother for at
least two and a half years. Females are not sexually
mature until about 4 years of age, which results in
polar bears having the lowest birth rate of any Arctic
animals.
Earlier in this century when polar bear populations
were thought to be declining, government took the
first step toward conservation by limiting the annual
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hunting season in 1935, and by restricting hunting to
Aboriginal people in 1949. Community quotas were
fixed in 1967, and in 1976 an international
agreement to conserve polar bears came into effect.
The agreement binds all five countries where polar
bears are found: Canada, Greenland, Norway,
Russia, and the United States.
The status of polar bear populations is closely
monitored. In the Canadian Arctic, where most of
the world's polar bears are found, annual research is
carried out to determine numbers and distribution.
This information is used to adjust community
quotas, which total about 600 bears per year.
When entering the polar bear's domain, one is well
advised not to be deceived by the animal's customary
shambling slow movement. This is an animal of
enormous strength, perseverance and ingenuity; it is
also capable of exceptional bursts of speed. Visitors
must always remain alert and not invite harm by
carelessly storing food or garbage.
ARCTIC BIRDS
The arrival of birds is greeted with great joy
by Inuit. The songs and beauty of birds are
appreciated by everyone. I am not sure
everyone enjoys them. Birds signal a
renewal of life and Inuit are thankful that the
winter is over, the first sighting of a snow
bunting is considered to be an important
event, indicating that other birds will follow
shortly. There are many beliefs about birds.
The Inuit also made full use of the birds they
caught. Some examples include:
• the ptarmigans red eyebrow was
used for decorating the atigi
• crane or loon heads were used for
dancing headgear
• in Sanikiluaq, they make beautiful
duck clothing
• bird tendons were used as alternate
thread
• feathers were used as dusters, to
wipe hands with and as brooms
Did you know …
Like us, birds need to breathe air
in and out of their lungs in order
to fulfill the cycle of bringing
oxygen into the body to be used
in metabolism, and to rid
themselves of the waste carbon
dioxide away from the body.
However, unlike us, when a bird
breathes the air does not go
simply in and out of the lungs in a
simple u-shaped path. Instead
birds' have a number of large
extensions called 'air sacs' and
hollow bones all interconnected
to their lungs. These allows the
air to flow around in a grand
circle meaning birds can have
fresh oxygen rich air in their lungs
all the time Also unlike we
mammals, a bird's breath is not
driven into and out of the lungs
by means of a diaphragm. In
birds, breathing is controlled by
muscular contractions of the
ribcage, which reduce or increase
the overall size of the body cavity
and thus force air out of the
various air sacs.
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•
•
•
•
•
•
•
STUDENT GUIDE
bird feathers were attached to arrows
loon skins were used as bags to keep
things dry or to carry embers while
travelling
the large bone on the swan's wing
was used as the stem of a pipe
the bills and other parts of birds were
often used as talismans or amulets
women's work bags were sewn from
the skin of swan's feet
windows were made from the swan's
gullet
loon and swan skins were used as
bags for rope when whale hunting
Source:
Inuuquatigiit ,
The Curriculum From
An Inuit Perspective,
Northwest Territories Education,
Culture and Employment, 1996.
Ε
Check Your Understanding
1. Create a list of the types of things that birds were used for (e.g.
decoration).
2. Why was it so important to make full use of the birds that were caught?
(had to supply all needs from what they hunted, also it is a form of respect
not to waste anything).
3. Observe and describe examples of some of the products made from birds
that are found in your community. If possible, bring them together for a
community showing.
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Birds arose from one of the dinosaur lineages and if
you look closely at the legs and toes of a bird you'll
see scaly reptilian-like skin. The vertebrate class
Aves includes an estimated 9000 species of birds
worldwide. Although descended from the dinosaurs,
birds have evolved remarkable specializations for
flight: a unique "one-way" breathing system, light
yet strong hollow bones, a skeleton in which many
bones are fused or lost, powerful flight muscles, and
– most importantly – feathers.
Over 100 species of birds from a dozen different
families can be seen in the arctic during the summer
but only 11 species spend the whole year in the
north. In most cases, it is food that draws them north
and sends them flying south again. For the hardy
birds that remain, there is no secret body form or
lifestyle that ensures survival; the amazing eleven
represent seven different families.
The tundra and the innumerable shallow, fish-free
bodies of water that result, is a perfect breeding
ground for insects. Many of the small perching birds
and shorebirds are drawn to the Arctic by the
abundance of these insects on the tundra and the
long days for gathering food for the nestlings. Birds
of prey may be drawn specifically by the abundance
of these small birds and for the numerous rodents
that are also reproducing at a rapid rate during the
summer. The marine environment with its annual
summer explosion of plankton draws other species.
Birds that live most of their live at sea are
collectively referred to as “seabirds” but this term
includes a number of different body forms and life
histories. And some species are seabirds for a major
part of the year and land birds for the rest.
Although there is a broad overlap of food amongst
different species and families, there are certain body
types in birds that give us a good idea of what they
feed on.
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Waterfowl are common in the Arctic in summer.
Tundra swans, geese and many ducks feed on fresh,
green water plants. Most Arctic marine ducks such
as the eiders and long-tailed ducks are “diving
ducks” or “sea ducks” and they feed on aquatic
invertebrates such as krill, which they dive
underwater for. All of these must migrate when the
days start to shorten and the ice starts to form.
All ducks must nest on the ground in the Arctic. As
is often the case with birds, the females are drably
coloured to help them hide while on the nest. The
common eider, one of the most widespread sea
ducks in the north, lines its nest with down from its
body. Like all ducks, eider ducklings are able to
move about and feed themselves almost as soon as
they hatch. Female eiders leave their ducklings for
care by “aunties,” non-breeding females who take
over as soon as the eggs hatch. They protect the
youngsters from attacks by gulls and jaegers. This
babysitting is probably very important for the female
who goes without food for a month while incubating
the eggs. This may be the reason that many species
of ducks establish “crèches” where several mothers
will combine their broods and leave them to the care
of one or two adults.
Shorebirds are distinguished by their long slender
legs and relatively thin bills. They frequent open
shoreline environments where they probe or pick
while looking for small aquatic insects, worms and
other small animals. Bill shape, body proportions,
and habitat are important clues to identification. For
example, the semipalmated plover has a relatively
short bill, bright orange legs and a black necklace
that contrasts with its white breast and throat. They
are found on mudflats and beaches across the Arctic.
All plovers perform a “broken wing” display to
distract predators or people who get too near their
nest. They are imitating injured and therefore easy
prey. The black-bellied plover goes even further – it
will carefully arrange itself on the eggs where there
is no nest.
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Four species of loons breed in the Arctic. The long,
powerful, pointed bill of the loon is the trademark of
a fish eater. The red-throated loon is the commonest
and most widespread of the loons in the Arctic and it
occurs along the entire coast. The red throat and
upturned bill is distinctive of this species. Loons are
excellent swimmers and divers and can even control
their buoyancy in the water by flattening their
feathers and expelling air from their lungs. In this
way they can simple sink out of sight. Loons pair for
life and both mother and father help with feeding
and caring for the youngsters. They sometimes swim
with their chicks riding on their back.
Only one representative of the Shearwater and
Fulmar family (Procellariidae) occurs in the Arctic.
The northern fulmar is a true seabird spending,
except for the breeding season, their whole life at sea
either flying or swimming. They look similar to
gulls but can be distinguished by their great
wingspan and by the long tubes that enclose their
noses. Their “tubenoses excrete the salt they absorb
from drinking seawater. Fulmars breed in colonies
on the same towering cliffs as do some other
seabirds. They are capable of defending themselves
by forcefully vomiting their stomach oil at an
intruder.
Ivory gull is one of eleven species of the family
Laridae that includes gulls, terns and jaegers. It is
also the only member of the family that lives yearround in the north. It is easy to recognize as it is
snow white with black legs; the only other white gull
is the glaucous gull, which is much larger and has
pink legs and feet. Little is known about the ivory
gull as they are true marine birds most often seen
flying out to sea or perched on ice floes. They are
probably the bird equivalent of the Arctic fox as they
seem skilled at scavenging the kills of other
predators. They also catch small fish. In winter, they
may follow polar bears or stay near the polynyas
where food is available.
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Long-tailed Jaegers are a member of the very large
gull family. They feature dramatically contrasting
colours, a very long tail, and a large, menacing,
hooked beak. Long-tailed jaegers are both predator
and parasite. Much of their food, they catch for
themselves including eggs, nestlings, birds,
mammals and fish. But they also steal food from
other birds either by harassing them in flight until
they drop it (then catching it in mid-air) or by
snatching it directly from the other birds bill. Jaegers
only come to land to breed and spend the winter in
the warmer portions of the Atlantic and Pacific.
Black guillemot belong to the same family as the
long-extinct great auk and together with the other
members of the family Alcidae are probably most
truly deserving of the term seabird. They are the
northern hemisphere’s equivalent of penguins but
guillemots and other auks can fly – both above and
below the water. They are adapted for marine life
and feed primarily on small fishes and small
crustaceans, which they pursue underwater. Black
guillemots are distinctive with their narrow pointed
bill, white wing patches, and bright orange feet.
They can dive to a depth of 30 metres. They breed in
small colonies on rocky shores, coastal cliffs and at
the base of boulders. Black guillemots are found in
the eastern Arctic; a close relative, the pigeon
guillemot, occurs in the western Arctic. This species
is the only auk that remains at high Arctic polynyas
throughout the winter.
Thick-billed murres are the largest and most
common of the auk family in the Arctic. They breed
in a few huge and very crowded colonies on rocky
cliffs. The sound and smell of the thousands of birds
living on these colonies is incredible. The female of
each pair of murres lays a single conical egg on a
ledge on the cliff. The egg’s shape helps prevent it
from rolling off. Timing of the egg laying is very
important as the adults may have to fly up to one
hundred kilometers to find food for the youngsters.
The youngsters leave their cliffside home before
they can fly: they simply jump or fall into the water.
They are than tended by the male for several weeks.
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While the chicks are mostly fed on fish, the adults
often take crustaceans, worms and mollusks, which
they will dive as deep as 100 metres to find.
Ravens are aggressive, clever, and inquisitive and
another of the few bird species that spend their entire
life in the Arctic. Ravens are the largest members of
the family Corvidae that includes crows and gray
jays (“whiskey jacks”). This family is also thought
to be the most intelligent. Ravens can be found all
over the Northern Hemisphere. In Canada, they are
chiefly restricted to the more uninhabited areas of
the country, but range throughout much of North
America, Europe, Asia, and northern Africa. The
raven is omnivorous, but it tends to be predatory,
and its diet embraces a wide variety of animal and
vegetable matter. Northern ravens are much larger
than their southern cousins and have been observed
acting as a team to kill baby seals. In the north they
are often called “crows”; crows are much smaller
and do not occur in the Arctic.
Specialized Adaptations
Birds have many types of structural adaptations that
enable them to live in a given habitat and play a
specific role in a food chain. The following
paragraphs highlight some of these adaptations.
Diving ducks including eiders and long-tailed ducks,
and loons are very good underwater swimmers. They
can dive to great depths and use their powerful,
webbed hind feet to propel themselves. To aid in
swimming underwater, their feet are set well back on
their body. This makes it difficult for them to
maneuver on land and most only come ashore to
nest. They also have smaller wings than do the
“puddle ducks”. As a result, they need a long stretch
of open water in which to take off.
The shape of the bill gives a good clue as to what it
feeds on. The broad bill of a dabbling duck is for
straining out vegetation. The bills of some diving
ducks such as eiders are designed for straining
amphipods from the water. Seabirds that eat fish
usually have long slender pointed bills that can be
turned very quickly when trying to grasp an agile
fish.
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The shape of Gull and Jaeger bills seem to be a
compromise between that of a predator that eats only
other animals and an omnivore, which eats both
vegetation and animals. The length and width of
their beaks are both moderately long. Their bills are
also hooked like an eagle or hawk but not as much.
This enables them to feed on a greater variety of
organisms unlike a loon that is restricted to a
specific diet based on its physiology.
Ravens may be the best example of a “generalist.”
They can kill small animals on their own, rip open
the carcasses of large animals that have died from
other causes, or pick berries off a bush.
Auks are the most specialized of seabirds. Their
adaptations include:
• Thick, waterproof feathers to keep them
warm
• Strong, pointed wings help them “fly”
underwater
• Webbed feet that help them swim on the
surface and underwater they act as rudders.
• Sharp, pointed bills for catching fish; puffins
(found only in the extreme eastern Arctic
during the summer) have spines on their
tongues and roof of their mouths to help
them hold slippery prey)
• Special gland near the eyes helps remove salt
from their food and water.
• Keen eyesight for spotting food and
predators at a distance. They will often head
for a feeding flock and join them.
Migration
The majority of Arctic marine birds depend on open
water for their survival so they must migrate
seasonally. Eastern auks usually migrate to open
water along the Atlantic coast of Canada and the
northern U.S. Western auks do the same along the
Pacific coast. Loons tend to migrate to wintering
grounds that are close to land as do the sea ducks
such as eiders. In all cases, the journey may take a
long time as all of these birds – and auks in
particular – are only modest fliers. Birds may use the
same wintering grounds year after year in the same
way that many are loyal to the same nest site or area.
"Astute Observers on the Sea Ice
Edge: Inuit Knowledge as a Basis
for Arctic Co-Management"
In the late 1980's, scientists'
knowledge of Hudson Bay Eiders
was fragmentary, restricted to the
open water period, and as
biologists themselves realized,
not adequate for the purposes of
making management decisions.
Biologists' observations were
generally restricted to the
traditional summer field season.
Data on Hudson Bay Eiders in
winter was virtually non-existent.
In 1986, two scientists took on
the task of piecing together
scattered scientific information to
estimate the Hudson Bay Eider
population size. Relying primarily
upon an aerial survey done
seven years earlier, these
scientists estimated the breeding
population to be 45,000 birds.
These results lead other
scientists to conclude that the
Hudson Bay Eider population
was suffering an annual 5%
decline.
(Continued next page…)
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Research undertaken to determine how birds
navigate during migration have produced interesting,
if slightly confusing results. Almost every
investigation into how they orient themselves has
shown positive results leading to the conclusion that
birds use a variety of methods in combination. The
primary sources are:
1. Topographic information including wind,
which can be affected by major landforms.
2. Stars
3. Sun
4. Earth’s magnetic field
5. Odours
There are other migrations besides the major “north
to Arctic” and “south to the open ocean” trips in the
spring and fall. Unlike gees and swans, which molt
once a year, ducks molt twice. This allows the males
in particular to shed their dull summer colours for
their mate-attracting winter plumage. With eiders
and some other sea ducks, the males migrate in large
flocks to safe “molting” areas far away from the
females on the nest. This migration is to find safe
tundra ponds far away from the predators that are
attracted to the nesting areas. One of the busiest
migration corridors in the summer is west from the
Beaufort Sea to areas in western Alaska. The males
will not return after the molt but will migrate south
on their own.
No migration story is complete without mention of
the Arctic terns. Arctic terns look like finely sculpted
black and white gulls with a long pointed bill and
pointed wings. They are true seabirds as well, rarely
coming to land except to nest. They feed primarily
on crustaceans and sometimes hovering over the
water before diving. But they are best known for
their annual migrations, which can be as much as
18,000 kilometres long. Some Arctic terns will
spend the winter at sea in the Antarctic where it is
summer. Arctic terns spend more time in sunlight
than do almost any other animal.
(… cont’d)
In 1985, however, ground
surveys of eider nest colonies in
southeastern Hudson Bay were
conducted by Makivik Research,
an Inuit organization, in
cooperation with Inuit
communities. This more exacting
data provided an estimate of
eider population size of 83,000
birds for eastern Hudson Bay
alone, 84% larger than the
scientists' estimate for all of
Hudson and James Bays.
Furthermore, this more recent
estimate suggests that rather
than declining, the Hudson Bay
Eider population may be
increasing annually by 7%.
by Douglas J. Nakashima,
found in
Traditional Ecological Knowledge:
Concepts and Cases, 1993
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MODULE 3 - LIVING ORGANISMS
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STUDENT GUIDE
Check Your Understanding
1. Why would there be such a lack of scientific data about the Eider Duck
populations in the late 1980's?
2. What are some reasons why there are such drastically different estimates
of what is happening to the Eider Duck population? Is there a right and a
wrong answer to the question of what is happening to the population?
3. What did the Makivik Research organization do in their attempt to
determine the Eider Duck population that scientists did not? What impact
might this action have on the results?
4. The role of traditional knowledge in conjunction with scientific data in
order to gain an understanding of Arctic ecosystems and make decisions of
how to manage resources continues to grow in importance. Identify an
example where scientists and local people are working together today to
gather information and make management decisions.
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MODULE 3 - LIVING ORGANISMS
STUDENT GUIDE
GLOSSARY FOR MODULE 3
Anadromous The term given to fish that migrate to the sea as sexually immature and
then migrate back to freshwater to breed.
Autotroph An organism that manufactures its own organic matter by using energy
from the sun or other sources.
Autotrophic Bacteria Bacteria that can produce complex organic molecules where
photosynthesis is not possible.
Amphidromous The term given to fish that migrate between freshwater and seawater
for purposes other than breeding.
Baleen The filter plates that hang from the upper jaws of baleen whales.
Baleen Whale Filter feeding whales. for example bowhead whales.
Benthic Belonging to the bottom of the ocean.
Carnivore A mammal with teeth that that eats other animals.
Carolus Linnaeus A Swedish biologist who simplified that problem of categorizing the
diversity of life by assigning every organism then known to a series of increasingly
specific groups.
Carrion The decaying body of a dead animal.
Catadromous The term given to fish that migrate to freshwater as sexually immature
and then migrate to seawater as adults to breed.
Cartilaginous Fishes with a skeleton made of cartilage: sharks, rays, skates and
ratfish.
Cetaceans Marine mammals with anterior flippers, no posterior limbs, and a dorsal fin:
whales, dolphins, and porpoises.
Copepods Small mostly planktonic crustaceans.
Crustacean These animals are arthropods adapted to live in water. They have two
pair of antennae, gills, and a calcified exoskeleton. e.g. krill, isopods, shrimp, lobsters,
etc.
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DDT A powerful insecticide which is effective on contact. Its chemical organic name is
Dichlorodiphenyltrichloroethane
DDE The major metabolite of DDT which is 150 times less toxic than DDT
Dieldrin an insecticide readily absorbed through the skin used in agriculture & forestry
and also against ticks, chiggers, sand flies and some species of mosquito's
Detritus Dead and decaying organic matter.
Diatoms Unicellular and eukaryotic autotrophs with a silicon skeleton; mostly
planktonic
Dinoflagellates Unicellular, eukaryotic, mostly autotrophic organisms with two
unequal flagella.
Echolocation The ability of some animals to sense their surroundings by analyzing
the reflection of sound waves, or clicks they emit.
Embryo The earliest stage of an animals development while it is still in the uterus.
Epipelagic The pelagic environment from the surface to a depth of 100 to 200 m.
Eukaryotic Complex cells that subdivide their activity into cellular organelles like
mitochondria.
Flagella A whip-like appendage that is usually used for locomotion.
Fluke The fin-like tail of cetaceans.
Frond The leaf-like blade of algae.
Gametophyte The haploid, gamete producing generation in many seaweeds.
Gestation Period The length of time between fertilization and birth.
Herbivore An animal that eats plants.
Heterotrophs Animals and bacteria that depend on the organic compounds produced
by other animals and plants as food; they are organisms not capable of producing their
own food by photosynthesis.
Holdfast The root-like base of marine algae that anchors the organisms to the
substrate.
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MODULE 3 - LIVING ORGANISMS
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Invertebrate Animals that lack a backbone.
Kelp Brown algae characterized by their large size and complexity. Some like the giant
kelp form dense kelp beds or kelp forests.
Krill Planktonic crustaceans that are an important food of whales and other animals.
Lactation The secretion of milk by the mammary gland.
Lateral Line A system of canals and sensory cells on the sides of fishes that help
them detect variations in the water.
Lichens The mutualistic combination of a fungus and green algae.
Littoral Zone (intertidal zone) The area between the highest and lowest tides.
Mammae The name of the glandular organs in a female that secrete milk.
Mitochondria The cell organelle responsible for the production of energy.
Mollusk Belonging to the phylum Mollusca that includes the snails, clams, and
octopuses.
Mutualism A symbiotic relationship in which both participants benefit.
Organelle A structure within a cell that performs one or more specialized functions.
Opercula The hard flaps that cover the gills in bony fish.
Otoliths These are small 'rocks' of calcium carbonate that are laid down in a fish's
inner ear to maintain balance.
Paralytic Causing paralysis, the stoppage of muscular motion due to neural blockage
or damage.
Pathogenic Bacteria Bacteria that can cause bacterial infections in mammals, fish
and invertebrates.
Pelagic Belonging to the water.
Phykoplankton The most important community of primary producers in the ocean;
photosynthetic plankton.
Pinnipedia The name of the 'order' in taxonomy of seals.
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Pneumatocysts The float structures of algae that contain gas.
Prokaryotic The most primitive of all one celled organisms. They have no nucleus.
Protists Members of the kingdom Protista, which consists of unicellular and eukaryotic
organisms. Many combine characteristics of both animal s and plants.
Saprobic Bacteria Bacteria responsible for the decomposition of organic matter. They
have been known to slowly degrade petroleum products.
Sporophyte The diploid, spore producing generation in many seaweeds.
Stipe Part of an algae plant that is similar to the stem of true plants.
Taxonomy The science of classification
Zygote The diploid cell that results from the fusion of an egg and a sperm cell.
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