Download SAWFISH IN PERIL

SAWFISH IN PERIL
© Doug Perrine
Orange High School Library
Sawfish In Peril
•Sawfish Basics
•Sawfish Biology
•Sawfish Conservation
•Sawfish Research
© Doug Perrine
SAWFISH BASICS
© Doug Perrine
What is a Sawfish?
• Sawfish belong to the family Pristidae
• Sawfish are characterized as having an elongate blade-like
snout (rostrum or saw) that has laterally placed tooth-like
denticles (rostral teeth)
How many species of sawfishes
are there?
© Doug Perrine
• There are 6-7 species of sawfishes currently recognized by
scientists
• Scientists are currently reviewing the taxonomy of
sawfishes, some species appear very similar to each other
How large can sawfishes grow?
© George Burgess
• They commonly reach 16.4 feet in length, attaining a
maximum length of 24 feet
Do sawfishes live off the coast
of the U.S.?
• The smalltooth sawfish is only found off the Atlantic and
Gulf coasts of Florida
• The largetooth sawfish is limited to the Gulf of Mexico
Why do sawfishes have that
remarkable tooth-studded saw?
© George Burgess
• The rostral “saw” is used for feeding, slashing back and
forth in the soft sediments in search of invertebrates and to
stun schooling fishes
• The “saw” is also used as defense against predators
Do sawfishes present a threat to
humans?
• Sawfishes are harmless to humans if left undisturbed
• Care must be taken when handling sawfishes as they may
defend themselves with the rostral “saw”
SAWFISH BIOLOGY
© Don DeMaria
Do sawfishes have bones?
U.S. Geological Survey
• No, sawfishes and other fishes belonging to the class
Chondrichthyes lack true bone, but rather have cartilaginous
skeletons
• Bony fishes (Class Osteichthyes) have true bones as do
humans - see photo above
How many fins do
sawfishes have?
Pectoral Fins
Pelvic Fins
Dorsal Fins
Caudal Fin
• They have two pectoral fins (fused to the head/trunk), two
pelvic fins, two dorsal fins, and a caudal fin
• Like the great majority of rays, sawfishes lack an anal fin
How long do sawfishes live?
• It has been estimated that these animals live up to 25 to 30
years, reaching maturity at 10 years
What do sawfishes eat?
© Doug Perrine
• Sawfishes feed on small fishes and invertebrates that can be
ingested whole through the mouth
• They only feed on prey that can fit into their small mouths
since they are unable to tear chunks off prey items with their
toothy saw
Do sawfishes have any
predators?
© Doug Perrine
• Adult sawfishes have very few predators
• Juvenile sawfishes are preyed upon by crocodiles, large
sharks, and even marine mammals such as dolphins
Do sawfishes have teeth in their
jaws?
• Ten to twelve rows of teeth
are located in jaws of the
smalltooth sawfish
• The teeth are rounded
anteriorly and have a blunt
cutting posterior edge
© George Burgess
Do sawfishes lay eggs or give
live birth to young?
• Sawfishes are "ovoviviparous", meaning that young
sawfishes grow from eggs retained within the mother
• After the embryos are fully developed, the mother sawfish
gives live birth with an average litter size of about 8 pups
SAWFISH
CONSERVATION
Are sawfishes listed as threatened
or endangered in the U.S.?
• On April 1, 2003 the U.S. National Marine Fisheries Service
placed the smalltooth sawfish on the Endangered Species List,
making it the first marine fish species to receive protection
under the Endangered Species Act
What are some threats to
sawfishes?
U.S. Geological Survey
• Entanglement in fishing gear and marine debris
• Indirect take as by-catch in other directed fisheries
• Loss of habitat, coastal development and marine pollution
• Use of saws as curios and the fins for soup
What should you do if you
encounter a sawfish in its natural
habitat?
© Doug Perrine
• Sawfish are listed under the Endangered Species Act which
makes it illegal to harm, harass, or handle them in any way
• If you do see a sawfish, enjoy the moment and feel extremely
lucky!
Are sawfishes ever accidentally
caught?
© Doug Perrine
• Sawfish are sometimes accidentally caught on fishing hooks
and in fishing nets
• If a sawfish is accidentally caught, it should be released
immediately to ensure its survival
Is it difficult to safely release a
captured sawfish?
• Sawfish are sometimes
accidentally caught on fishing
lines and in fishing nets
• Guidelines are available on
what to do if a sawfish is hooked
or if a sawfish is tangled in a net
• Encounters should be reported
to assist with ongoing scientific
research
Did fishermen catch sawfishes prior
to their protection in the U.S.?
• Sawfish were often caught by fishermen who would
sometimes eat the flesh and keep the trophy “saw”
• Very large sawfishes were often captured in past decades
SAWFISH RESEARCH
What do scientists still need to learn
about sawfish?
• Scientists are
researching age and
growth, reproduction,
movement patterns,
and habitat use of the
smalltooth sawfish to
assist in management
and recovery of this
endangered species.
What is the
Sawfish Recovery Team?
• This team consists of researchers, managers, and
representatives from constituent groups working to develop a
recovery plan for the smalltooth sawfish
• http://www.flmnh.ufl.edu/fish/sharks/sawfish/srt/srt.htm
What are some good resources to
learn more about sawfishes?
• There are some good web sites to learn more about sawfishes
• You can also read more about sawfishes in scientific journals
and books
Questions/Answers?