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Conservation biology of the smalltooth sawfish: science to help save the USA's first endangered elasmobranch Tonya Wiley and Beau Yeiser Center for Shark.

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Presentation on theme: "Conservation biology of the smalltooth sawfish: science to help save the USA's first endangered elasmobranch Tonya Wiley and Beau Yeiser Center for Shark."— Presentation transcript:

1 Conservation biology of the smalltooth sawfish: science to help save the USA's first endangered elasmobranch Tonya Wiley and Beau Yeiser Center for Shark Research Elasmobranch Conservation Biology Program

2 What are sawfish? Members of the family Pristidae Members of the family Pristidae A type of ray A type of ray All possess the distinctive toothed rostrum or saw All possess the distinctive toothed rostrum or saw Inhabit tropical and subtropical coastal, estuarine and fresh waters Inhabit tropical and subtropical coastal, estuarine and fresh waters Seven known species, six in Pristis Seven known species, six in Pristis Taxonomy is still confused and needs revision Taxonomy is still confused and needs revision Historically largetooth and smalltooth sawfish in the US Historically largetooth and smalltooth sawfish in the US

3 Pristis pectinata in US waters Historically common from the Mexican border to Carolinas Historically common from the Mexican border to Carolinas Summer migrations from Florida and Georgia north to Carolinas and Virginia (and sometimes even Long Island) Summer migrations from Florida and Georgia north to Carolinas and Virginia (and sometimes even Long Island)

4 The decline of P. pectinata From 1900 to 2000 the population is estimated to have declined in excess of 95% From 1900 to 2000 the population is estimated to have declined in excess of 95% Extirpated from most of its historic range, only occurs regularly in southwest Florida and Florida Keys Extirpated from most of its historic range, only occurs regularly in southwest Florida and Florida Keys Louisiana sawfish abundance

5 The causes of the P. pectinata decline Mortality in fisheries (commercial and recreational), especially due to nets Mortality in fisheries (commercial and recreational), especially due to nets Loss of important nearshore habitat, especially for the juveniles Loss of important nearshore habitat, especially for the juveniles Late maturing, produce few young Late maturing, produce few young

6 Male Size at Maturity Previous data 270 cm (~9 feet) New data between 320-372 FL 340-395 STL (~11 feet) March 2002-Nine Mile Bank March 2003-Nine Mile Bank May 2007-East Cape Canal July 2007-Florida Keys May 2007-East Cape Canal

7 The USA’s first endangered elasmobranch TOC petitioned for ESA listing in 1999 TOC petitioned for ESA listing in 1999 Status review Status review April 1, 2003 April 1, 2003 P. pectinata was added to the US Endangered Species List P. pectinata was added to the US Endangered Species List Also: Also: –Protected in Florida since 1992 –Critically Endangered listing by IUCN –Endangered Listing by AFS –CITES Appendix 1

8 Mote research on P. pectinata Goal is to provide the scientific basis for population recovery Goal is to provide the scientific basis for population recovery –Determination of distribution and abundance –Identification of critical habitat –Population genetics –Population and habitat modeling

9 Outreach & Education Ask the public to report any captures or sightings of sawfish Ask the public to report any captures or sightings of sawfish Texas to North Carolina Texas to North Carolina Public can easily identify sawfish correctly Public can easily identify sawfish correctly Due to rarity, the public is a good way to sample a wide area continuously Due to rarity, the public is a good way to sample a wide area continuously

10 Sawfish encounters 1998-2007

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12 Size and depth distributions Full size range of animals reported Full size range of animals reported Majority of animals reported are juveniles Majority of animals reported are juveniles Small P. pectinata limited to shallow waters (<5m) Small P. pectinata limited to shallow waters (<5m) Larger P. pectinata have a wider depth distribution Larger P. pectinata have a wider depth distribution

13 Field Surveys Gillnet and seine Rod and reel Longline

14 Spring Juvenile Surveys 13 sawfish captured 11 YOY 2 Immature 2 new nursery locations (Huston Coves & Bay) Grocery Creek Mud Bay Last Huston Bay Huston Coves East Cape Canal Whitewater Bay Eagle Key

15 Habitat use through manual tracks

16 Habitat use by juvenile P. pectinata Movements are strongly influenced by tide Movements are strongly influenced by tide Remain in very shallow water (<50 cm) Remain in very shallow water (<50 cm) Relatively small home range over short periods (days) and often longer periods (months) Relatively small home range over short periods (days) and often longer periods (months) High tide Mid tide Low tide

17 Habitat use by juvenile P. pectinata

18 Site fidelity studies Use moored acoustic listening stations to record the presence/absence and movements of sawfishUse moored acoustic listening stations to record the presence/absence and movements of sawfish

19 Satellite telemetry of large P. pectinata Wildlife Computers PAT tags used to examine longer- term movements of sawfish Wildlife Computers PAT tags used to examine longer- term movements of sawfish Archive location, depth and temp. data and then send via satellite after pop-up Archive location, depth and temp. data and then send via satellite after pop-up

20 Satellite Tagging Four sawfish: 400 cm TL F - Nov 2006 382 cm TL F - Nov 2006 210 cm TL F - May 2007 330 cm TL M - May 2007

21 Satellite Tagging-Results Two females Data from November 2006 to February 2007 Similar depth profile Data still being analyzed

22 Starting this Fall… Monitor the movements, residency time, possible aggregations and habitat use of large sawfish in Everglades National Park and the Florida Keys using BRUVS, and PAT and SPOT tags BRUV’s

23 Critical habitat for P. pectinata The next step is to determine critical habitat The next step is to determine critical habitat Depth, salinity, temperature, substrate etc Depth, salinity, temperature, substrate etc –Juvenile areas Pupping Pupping Growth to maturity Growth to maturity –Adult areas Feeding Feeding Mating Mating Aggregations Aggregations Migrations Migrations

24 Critical habitat of P. pectinata Major factors appear to be: Major factors appear to be: –Estuarine areas (especially around river months and lower reaches of rivers) –Shallow banks along mangrove shorelines (juveniles) –Deep channels through shallow areas (adults)

25 Genetics Collaborations Demian Chapman (Pew Institute for Ocean Science) and Kevin Feldheim (The Field Museum) Demian Chapman (Pew Institute for Ocean Science) and Kevin Feldheim (The Field Museum) Objective 1: Determine whether multiple discrete breeding populations of sawfish remain in the U.S. that should each be managed independently and locally or whether there is only one breeding population that should be managed as a unit, co- operatively by federal and state agencies. (philopatry, relatedness) Objective 1: Determine whether multiple discrete breeding populations of sawfish remain in the U.S. that should each be managed independently and locally or whether there is only one breeding population that should be managed as a unit, co- operatively by federal and state agencies. (philopatry, relatedness) Objective 2: Assess the population history of smalltooth sawfish in their SW Florida “stronghold” and determine whether they have suffered a loss of genetic diversity that may compromise their ability to survive and reproduce in the future. Objective 2: Assess the population history of smalltooth sawfish in their SW Florida “stronghold” and determine whether they have suffered a loss of genetic diversity that may compromise their ability to survive and reproduce in the future. Mahmood Shivjy-Nova Southeastern University Mahmood Shivjy-Nova Southeastern University Objective: DNA forensics to identify species of fins and rostra in trade Objective: DNA forensics to identify species of fins and rostra in trade

26 Acknowledgements National Marine Fisheries Service National Marine Fisheries Service Disney Wildlife Conservation Fund Disney Wildlife Conservation Fund Florida Fish and Wildlife Conservation Commission Florida Fish and Wildlife Conservation Commission Munson Foundation Munson Foundation Florida Power & Light Florida Power & Light National Fish and Wildlife Foundation National Fish and Wildlife Foundation National Geographic Conservation Trust National Geographic Conservation Trust John Ball Zoo Society John Ball Zoo Society Mote Scientific Foundation Mote Scientific Foundation

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