Download the value of hunter-provided bowhead whale

THE VALUE OF HUNTER-PROVIDED BOWHEAD WHALE SAMPLES: WHAT WE COLLECT AND WHY
AN OVERVIEW OF NSB-DWM BOWHEAD WHALE HEALTH ASSESSMENT MONITORING
EYEBALLS
SKIN SAMPLES
BLUBBER
The eyes are used to
age older whales. The
lens is the oldest protein in the body. It
contains a material called aspartic acid,
which exists in two forms: “A” form and
“B” form. When a whale is born, it is
almost all in “A” form. As the whale’s life
passes, it slowly converts to the “B” form.
By looking at a comparison of the levels
of these two forms, we can get a good
idea of how old these whales are.
We are very interested
in the skin condition
of whales. Skin can say
a lot about the health of an individual, as
well as the population. Skin can tell us if
whales are being affected more often by
human-caused injuries, such as rope
wounds and propeller scars. Other things
we look for include wounds from
predators and evidence of viral and
bacterial diseases. The skin records these
“insults” and often stores them in the
form of a scar. We collect frozen and
formalin-fixed skin samples, along with
pictures of what we see on each whale we
examine.
Blubber is one of the most
important tissues that we
collect! The amount of fat it contains tells
us much about the body condition of the
animal. By monitoring the amount of fat
present in the blubber over extended
periods of time (years), scientists can learn
about the health of the population, the
health of the ecosystem and possibly about
the effects of global climate change on the
species. Blubber (fat) is also monitored for
man-made contaminants. Certain types of
toxins build up specifically in fat. Previous
studies have shown that bowheads have
very low concentrations of fat-based
contaminants in their blubber (maktak).
BALEEN
We sample the
longest
plate
of
baleen to age the younger animals and
also for studies that look at “what and
where” bowheads eat. The Chukchi and
the Beaufort Seas each have specific
carbon and nitrogen “signatures”, which
means the prey the bowheads feed on
are different in each area. Bowheads
migrate only once a year, so the shift
between the Chukchi “signature” and the
Beaufort “signature” gets recorded in the
baleen as it grows, and creates a cycle.
By counting these cycles, we can tell
where the animal has eaten and how old
it is (up to age 15).
MUSCLE
Lean body mass (the nonblubber part made up of
muscle or “meat”) is a potentially
important measure of body condition in
bowhead whales. We monitor the whales
for the amount of muscle present, its
nutritional value, and for parasites.
Muscle parasites have not been seen in
bowheads, and the meat from bowhead
whales has been found to be a very
nutritious part of the Inupiat diet.
OVARIES
Ovaries are weighed,
measured and examined to
determine if the whale is old enough to
reproduce. Additionally, ovaries can be
sectioned and small scars left behind after
ovulation can be counted to aid in age
determination.
kidney is a very
KIDNEY The
important filtration
system for the body. It rids the
blood of waste and toxins. We monitor the
kidney microscopically for signs of health
and age-related changes. We also analyze
pieces of kidney to check for changes in the
amounts of elements (such as selenium,
cadmium or mercury) that are present.
FECES
We collect
“poop”
from each whale for a
variety of reasons. We
look for evidence of
intestinal parasitism
here. Feces are also analyzed for “stress”
hormones. Because feces is produced and
present in the colon before the whale is
chased during the hunt, it may be one of
the best places to look for increases in
resting hormone levels (stress hormones in
blood are likely change very quickly in
response to recent, short-term stress (such
as the hunt). It is important to be able to
separate long-term (chronic) stress from
short-term (acute) stress. We also freeze
and save feces for use in future studies.
BLOOD
Blood is sampled for
a variety of reasons,
including examining serum for
evidence of viral and bacterial
disease exposure, counting white
blood cells to check for signs of infection
or inflammation. We also freeze blood for
use in future studies.
PHOTOGRAPHS
Photographs of
scars,
skin
problems, or any unusual findings in
harvested bowhead whales are very
important to document. Sometimes it is
difficult for scientists to identify the early
stages of change (examples: the early
signs of stress of injury related to
increased ship traffic or the first cases of
a new disease in the population).
Photographs provide a record of these
changes that can be revisited in the
future. Additionally, aerial and ice-based
photographs of bowhead whales may
provide
valuable
Information
on body
condition.
TESTES
We weigh and
measure the
testes to learn about the
reproductive status of male
bowheads. We also look at tissue from the
testes under the microscope for signs of
sperm production- as evidence of
reproductive maturity. From prior research,
we have found that male bowheads
become sexually mature in their early
twenties. Additionally, we are researching
the possibility of seasonal differences in
breeding activity.
THYROID GLANDS
The thyroid
gland
is
very important in the regulation of energy
use (metabolism) in mammals. Research in
other marine mammals has shown
abnormalities in thyroid hormone levels
can be caused by certain types of
contaminants. We collect tissue from the
thyroid gland and look at this along with
thyroid hormone levels in the blood to
make sure they appear normal. Over the
last ten years we have learned much about
thyroid hormone levels in bowhead whales,
including the differences between young
and old whales, and whales
in spring versus fall. So far,
no abnormalities have been
found in the bowhead whale
thyroid
gland,
but
we
continue to monitor it as part of a longterm health assessment program.
PANCREAS
The pancreas produces
insulin. Insulin is critical
for regulation of sugar (energy) in
mammals. When looked at under a
microscope, the pancreas is made up of
structures that make insulin, and clusters of
cells that hold a granular material called
“zymogen”. Zymogen decreases in animals
that are in poor nutritional condition. We
monitor the presence and amount of this
substance,
along
with
the
general
microscopic appearance of the pancreas
as indicators of body
condition and nutritional
health. Since 1998, the
pancreatic tissue
we’ve examined in
whales has been healthy.
LIVER
The liver is one of the
major filtration systems
in the body (along with the
kidney). The liver helps the body
deal with toxins. We look at
frozen and preserved liver
samples
for
general
microscopic
appearance, contaminant concentrations,
and vitamin, mineral and metal levels.
spleen is a
SPLEEN The
organ important
in the immune system and in
the production of red blood
cells. We monitor the
microscopic appearance of the spleen for
abnormalities that may signify health
problems.
STOMACH CONTENTS
The food (or “prey”) found in the stomachs
of hunted bowhead whales is collected to
see what the whales are eating. The species
of prey are identified in order to learn
about what types of food the bowheads are
feeding on at different times of year and if
this is changing over time. This information
also helps researchers create
maps of bowhead feeding
areas, which are very important
to protect.
URINE
Bowhead whales have kidneys
that perform incredibly well- so
well that scientists do not fully understand
how it is possible! Bowheads do not drink
fresh water and their food is very salty.
Somehow bowhead “super kidneys” are able
to filter the blood and keep the whales in
proper water balance. We monitor urine as a
measure of kidney function. We also plan to
monitor urine for stress hormones in the
near future.
ADRENAL GLANDS
The adrenal
glands are
highly important in stressful situations.
They produce many of the stress
hormones, such as adrenaline, that allow
the body to respond properly during
stressful events. Past and future research
will look at the microscopic appearance of
the adrenal gland along with levels of
stress hormones present in the blood,
blubber, feces (poop) and urine.
HEALTHY ANIMALS, HEALTHY SUBSISTENCE FOODS
MEASUREMENTS
Everyone is interested in how
long their whale is, but this is
just one of many measurements
made on each whale landed in the hunt. By
measuring “girths” or the distance around the whale
at several spots, we can make size comparisons to
whales caught in the past. This allows us to
understand changes in body condition over the years.
Generally, plump whales mean they are eating wellespecially when the plump whales are ingutuks
(yearlings). If the ingutuks are doing well, it means
their mothers are providing the nutrition they need
to grow thick blubber and their portly appearance.
We also measure things such as baleen length (which
can relate to age) and ovary and testicle size. The
size of ovaries and testes relate to the reproductive
status of the animal. The age that a whale is able to
first reproduce is very important to understanding
population health. Also, new research shows we may
be able to estimate age by the size of the flippers
(taliguq) and the peduncle or “itigruk”.