BY THE CENTER FOR SHARK RESEARCH,

Transcription

1 RESOURCE INFORMATION RESEARCH ON THE BLACKTIP SHARK AND OTHER COASTAL SHARKS BY THE CENTER FOR SHARK RESEARCH, FINAL REPORT NOAA/NMFS GRANT NA07FM0459 SUBMITTED To: NOAAlNMFS Office of Sustainable Fisheries Highly Migratory Species Division 1315 East-West Highway Silver Spring, MD SUBMITTED By: Robert E. Hueter Center for Shark Research Mote Marine Laboratory FEBRUARY 28, 2002 Mote Marine Laboratory Technical Report 817 This document is printed on recycled paper

2 TABLE OF CONTENTS EXECUTIVE SUMMARY PROJECT INFORMATION SUMMARY OF PROJECT ACCOMPLISHMENTS AND EXPENDITURES Work Accomplishments Primary Project Tasks Summary of Results Field Research in Quintana Roo, Mexico Field Research in Western Gulf of Mexico Offshore Large Shark Surveys Fishery Ecosystem Modeling Florida Coastal Relative Abundance Surveys Age/Growth Studies Tagging Database Response to NMFS Needs Publications and Conferences Major Findings and Conclusions Expenditures SIGNATURE

3 EXECUTIVE SUMMARY Mote Marine Laboratory's Center for Shark Research (CSR) is an independent, international research center established by the U.S. Congress in 1991 and dedicated to the multidisciplinary study and public understanding of sharks, skates and rays. In , the CSR continued its mission to conduct scientific studies on sharks in cooperation with the National Marine Fisheries Service (NOAAlNMFS) to respond to the agency's need for biological data in order to manage shark fisheries. The primary emphasis of this research and information program involved biological assessments of sharks as a fishery resource. This project addressed major gaps in our resource information base for the blacktip shark (Carcharhinus limbatus), a common large coastal shark species inhabiting nearshore waters of the U.S. east coast. To assist NMFS in its objective to rebuild this important fishery, the primary research activities undertaken by the CSR in this project were new studies on the stock structure, life history, ecology and population biolog'y of the blacktip shark and other large and small coastal sharks inhabiting state and federal waters of the Gulf of Mexico. This research was conducted primarily in the Gulf of Mexico off the U.S. coast (Florida and Texas), along the U.S. southeastern Atlantic coast (South Carolina) and along the Mexican Gulf coasts of Tamaulipas and Quintana Roo. New technology in the form of archival and satellite tags were deployed on large sharks of the region. The work in Mexico was conducted in collaboration with the Instituto Nacional de la Pesca (INP). The CSR also served as a center for the public understanding and communication of information on sharks and for national and international exchanges on issues relating to shark biology. Through these various activities the CSR significantly advanced the course of shark research and fisheries conservation and management in , and continued to serve as a productive partnership between Mote Marine Laboratory and the National Marine Fisheries Service. 1

4 PROJECT INFORMATION Award Number: NA07FM0459 Amount of Award: Federal $ 150,000 Match $ 25,848 Total $ 175,848 Project Title: Resource Information Research on the Blacktip Shark and other Coastal Sharks by the Center for Shark Research, Recipient: Mote Marine Laboratory, Sarasota, Florida Award Period: July 1, 2000 to June 30, 2001 Period Covered by this Report: July 1, 2000 to June 30, 2001 (Final Report) 2

5 SUMMARY OF PROJECT ACCOMPLISHMENTS AND EXPENDITURES Work Accomplishments Primary Project Tasks: The following primary tasks were scheduled for this project: a. Shark field research in Quintana Roo, Mexico; b. Shark field research in the western Gulf of Mexico along the Texas/Mexico coast; c. Offshore large shark surveys; d. Fishery ecosystem modeling; e. Florida relative abundance surveys of coastal sharks; f. Studies of shark age and growth; g. Maintenance and analysis of CSR shark-tagging database; h. Response to NMFS requests for information; i. Communication of scientific results through publications and conferences. Summary of Results: a. Field Research in Quintana Roo, Mexico CSR shark nursery studies and fishery surveys were continued in the Gulf of Mexico coastal waters of Mexico during the project period, in cooperation with NMFS and Mexico's Instituto Nacional de la Pesca (INP) in response to a research initiative of the MEXUS/Gulf program. One field trip to the Gulf coast of Mexico was conducted by CSR and INP staff on May 29 to June 7, 2001, to Laguna Yalahau on the northern coast of Quintana Roo. On previous trips to the area by CSR personnel the lagoon has been found to be a productive shark nursery, particularly for the blacktip shark (Carcharhinus limbatus). The following report, filed with the help of CSR Senior Biologist John Tyminski who led this year's field trip, summarizes the activities and findings of this trip: Trip Objectives: 1) Collect fin clips (75) from neonate and young-of-the-year (YOY) blacktips (C. limbatus) to contribute to population genetics studies of the blacktip shark. 2) Utilizing the aid of artisanal fishermen, conduct a Peterson Mark-Recapture study to estimate the number of blacktip pups in the lagoon. 3) Collect data and pay rewards from the previous year's recaptures and generally continue to strengthen our relationship with the local fishermen, fisheries officials, other researchers, and the local people by further conveying our research goals in the area. 3

6 Methods: The first field day (May 30) was used as a training day to ensure all field personnel were performing the necessary field activities in an identical manner (Le. net checking, tagging, releasing, data collection, fin clipping etc.). On this day we utilized only one boat and split the crew into morning and afternoon shifts. A sufficient number of sharks was captured this first day to confidently proceed with two boats on the subsequent days. The boats fished in the manner typical of previous years where the nets were, ideally, set through turbid areas ("turbios"), thoughtto be places of denser concentration of blacktip sharks. This was not always possible as heavy cloud cover and rough conditions did not always permit the efficient sighting of these murkier areas. When possible, the two boats worked as a team to systematically traverse the lagoon in order to locate the most productive fishing areas. The areas sampled were mostly confined to the western end of the lagoon (Fig. 1). For the purpose of the Peterson Mark-Recapture study, fishing/tagging began May 30 and continued each day until the late afternoon of June 2. No fishing was conducted on the following day (June 3) to allow the tagged sharks to re-distribute in the lagoon as per the study design. Fishing resumed in the early morning of June 4 and was concluded in the afternoon of June 6. As in previous years, fishing was conducted with the assistance of local commercial fishermen (Fig. 2) and all live sharks were tagged and released by CSR and/or INP biologists (Fig. 3). Figure 1. Gill net sampling sites (71 sets) in Laguna Yalahau in '.1.If." 4

7 Figure 2. Mexican artisanal commercial fisherman setting gillnet for small sharks in Laguna Yalahau. Figure 3. CSR biologist releasing tagged neonate blacktip shark in Laguna Yalahau. Summary of Results: General: Number of Gillnet Sets Conducted - 71 Number of Gillnet Sets Catching Sharks - 60 Total Number of Sharks Caught (Table 1) Total Number of Sharks Tagged (Table 1) Number of 8ycatch Species - 37 (Table 2) Table 1. Sharks collected in Laguna Yalahau, Quintana Roo, Mexico, May/June (PCl = precaudal length; Fl = fork length; STl = stretch total length; CONDITION = release condition from 1-5, where 1 is best) Sample' SCIENTIFIC NAME SEX PCl (cm) Fl(cm) Tl (cm) STl (em) TAG. WEIGHT (kg) CONDITION M337 Carcharhinus limbatus M M M337 Carcharhinus limbatus M M M337 Carcharhinus limbatus F M M339 Carcharhinus limbatus F M M339 Carcharhinus limbatus F M M339 Carcharhinus limbatus F M339 Carcharhinus limbatus M M M340 Carcharhinus limbatus M M M342 Carcharhinus limbatus F M M342 Carcharhinus limbatus F M M342 Carcharhinus limbatus M 46 I M M342 Carcharhinus limbatus F M M342 Carcharhinus limbatus F M M342 Carcharhinus limbatus M M M342 Carcharhinus limbatus F M M343 Carcharhinus limbatus F M M343 Carcharhinus limbatus M M M343 Carcharhinus limbatus F M

8 M343 Carcharhinus limbatus M M343 Carcharhinus limbatus M M M343 Carcharhinus limbatus M M M343 Carcharhinus limbatus M M M343 Carcharhinus limbatus F M M343 Carcharhinus limbatus M M M343 Carcharhinus limbatus F M M343 Carcharhinus limbatus F M M343 Carcharhinus limbatus M M343 Carcharhinus limbatus M M2026 M343 Carcharhinus limbatus F M M343 Carcharhinus limbatus F M M343 Carcharhinus limbatus M M M343 Carcharhinus limbatus F M343 Carcharhinus limbatus M M343 Carcharhinus limbatus F M343 Carcharhinus limbatus F M M343 Carcharhinus limbatus M M M343 Carcharhinus limbatus F M M343 Carcharhinus limbatus F M M343 Carcharhinus limbatus M M2035 M343 Carcharhinus limbatus F M M343 Carcharhinus limbatus M M343 Carcharhinus limbatus F M2038 M343 Carcharhinus limbatus M M M343 Carcharhinus limbatus F M M343 Carcharhinus limbatus M M M343 Carcharhinus limbatus M M M343 Carcharhinus limbatus M M343 Carcharhinus limbatus F M343 Carcharhinus limbatus M M M343 Carcharhinus limbatus M M343 Carcharhinus limbatus F M M343 Carcharhinus limbatus F M M344 Carcharhinus limbatus F M M344 Carcharhinus limbatus M M M344 Carcharhinus limbatus M M344 Carcharhinus limbatus F M M344 Carcharhinus limbatus M M M344 Carcharhinus limbatus F M M344 Carcharhinus limbatus M M M344 Carcharhinus limbatus F M M344 Carcharhinus limbatus F M M344 Carcharhinus limbatus F M M345 Carcharhinus limbatus F M M345 Carcharhinus limbatus M M M345 Carcharhinus limbatus F M M346 Carcharhinus limbatus F M

9 M346 Carcharhinus limbatus M M M346 Carcharhinus limbatus F M M346 Carcharhinus limbatus F M M346 Carcharhinus IimbBtus F M M346 Carcharhinus IimbBtus F M M346 CBrcharhinus limbatus M M M346 CBrchBrhinus lilt' :~ J":S M M M346 CarchBrhinus limt. ::us I M M M346 Carcharhinus IimbBtus F M346 Carcharhinus limbatus M M M347 Carcharhinus IimbBtus F M M347 CarchBrhinus limbatus M M M347 Carcharhinus limbatus F M M347 Carcharhinus limbatus F M M347 CarchBrhinus IimbBtus M M M347 CBrcharhinus limbbtus M M M347 Carcharhinus limbatus M M2256 M347 Carcharhinus limbatus F M M347 CBrchBrhinus limbatus M M M347 Carcharhinus limbbtus F M M347 Carcharhinus IimbBtus F M M347 CBrcharhinus limbatus F M M347 Carcharhinus IimbBtus M M M347 Carcharhinus limbatus M M2263 M347 Carcharhinus limbatus F M M347 Carcharhinus limbatus M2265 M347 Carcharhinus limbatus M M M347 Carcharhinus limbatus M M M347 Carcharhinus limbatus M M M347 Carcharhinus limbatus F M2269 M347 Carcharhinus limbatus F M M347 CarchBrhinus limbbtus M M M347 Carcharhinus IimbBtus M M M347 CarchBrhinus limbbtus M M M347 Carcharhinus limbatus M M M347 Carcharhinus IimbBtus M M M347 Carcharhinus limbatus M M M347 CarchBrhinus limbatus F M M347 CarchBrhinus limbatus M M M347 CBrchBrhinus limbatus M M M347 Carcharhinus IimbBtus F M M347 Carcharhinus limbatus F M M347 Carcharhinus limbatus F M M347 Carcharhinus IimbBtus F M M348 Carcharhinus limbatus F M M348 CarchBrhinus limbatus M M228~ M348 Carcharhinus limbatus M M M348 Carcharhinus IimbBtus F M

10 M348 Carcharhinus limbatus M M M349 Carcharhinus limbatus M M M349 Carcharhinus limbatus F M M349 Carcharhinus limbatus M M M349 Carcharhinus limbatus M M350 Carcharhinus limbatus F M350 Carcharhinus limbatus M M351 Carcharhinus limbatus F M351 Carcharhinus limbatus F M M351 Carcharhinus limbatus F M M352 Carcharhinus limbatus M M M353 Garcharhinus limbatus M M M354 Carcharhinus limbatus F M M354 Carcharhinus limbatus F M M354 Carcharhinus limbatus F M M355 Carcharhinus limbatus F M M356 Carcharhinus limbatus M M M356 Carcharhinus limbatus F M M356 Carcharhinus limbatus M M M357 Carcharhinus limbatus F M M358 Carcharhinus limbatus M M M358 Carcharhinus limbatus F M M359 Carcharhinus limbatus M M M359 Carcharhinus limbatus M M M361 Carcharhinus limbatus M M M361 Carcharhinus limbatus M M M363 Carcharhinus limbatus F M M363 Carcharhinus limbatus M M M363 Carcharhinus limbatus F M M364 Carcharhinus limbatus F M M365 Carcharhinus limbatus F M M365 Carcharhinus limbatus F M366 Carcharhinus limbatus M M M366 Carcharhinus limbatus F M M366 Carcharhinus limbatus F M366 Carcharhinus limbatus F M M366 Carcharhinus limbatus M M M366 Carcharhinus limbatus M M M366 Carcharhinus limbatus F M I 2 M366 Carcharhinus limbatus F M M366 Carcharhinus limbatus F M366 Carcharhinus limbatus F M366 Carcharhinus limbatus F M367 Carcharhinus limbatus M M M367 Carcharhinus limbatus M M M367 Carcharhinus limbatus M M M368 Carcharhinus limbatus M M M369 Carcharhinus limbatus F M

11 M369 Carcharhinus Iimbatus M M M369 Carcharhinus limbatus F M M370 Carcharhinus limbatus M M M370 Carcharhinus Iimbatus M M M370 Carcharhinus Iimbatus F M M370 Carcharhinus Iimbatus M M371 Carcharhinus Iimbatus I F M M371 Carcharhinus limt atus F M M372 Carcharhinus Iimbatus F M M372 Carcharhinus Iimbatus F M M372 Carcharhinus limbatus F M M373 Carcharhinus limbatus F M M373 Carcharhinus Iimbatus F M M373 Carcharhinus Iimbatus M M373 Carcharhinus limbatus F M M373 Carcharhinus limbatus F M M373 Carcharhinus Iimbatus M M M373 Carcharhinus Iimbatus F M M375 Carcharhinus Iimbatus F M M375 Carcharhinus Iimbatus M M375 Carcharhinus Iimbatus M M M375 Carcharhinus Iimbatus F M375 Carcharhinus Iimbatus F M375 Carcharhinus limbatus M M375 Carcharhinus Iimbatus F M375 Carcharhinus limbatus M M375 Carcharhinus limbatus M M M375 Carcharhinus Iimbatus F M M376 Carcharhinus limbatus F M M377 Carcharhinus Iimbatus F M M379 Carcharhinus Iimbatus M M M379 Carcharhinus limbatus F M M380 Carcharhinus Iimbatus M M M382 Carcharhinus Iimbatus F M M382 Carcharhinus Iimbatus M M M382 Carcharhinus limbatus M M M382 Carcharhinus Iimbatus M M M382 Carcharhinus Iimbatus M M M382 Carcharhinus Iimbatus F M M382 Carcharhinus Iimbatus F M M382 Carcharhinus limbatus M383 Carcharhinus Iimbatus F M M383 Carcharhinus limbatus M M384 Carcharhinus limbatus M M M384 Carcharhinus Iimbatus M M M385 Carcharhinus Iimbatus F M M385 Carcharhinus Iimbatus F M M386 Carcharhinus limbatus M M

12 M387 Carcharhinus Iimbatus M M M387 Carcharhinus Iimbatus F M M387 Carcharhinus Iimbatus M M M387 Carcharhinus limbatus M M M387 Carcharhinus Iimbatus F M M387 Carcharhinus Iimbatus F M M387 Carcharhinus Iimbatus F M M387 Carcharhinus Iimbatus F M M388 Carcharhinus Iimbatus F M M389 Carcharhinus Iimbatus F M389 Carcharhinus limbatus F M M389 Carcharhinus limbatus F 44 I M M390 Carcharhinus Iimbatus M M M390 Carcharhinus Iimbatus F M M390 Carcharhinus limbatus M M M390 Carcharhinus Iimbatus M M M390 Carcharhinus limbatus F M M390 Carcharhinus Iimbatus M M M391 Carcharhinus Iimbatus F M M391 Carcharhinus Iimbatus F M M392 Carcharhinus limbatus M M M392 Carcharhinus limbatus F M M392 Carcharhinus limbatus F M M395 Carcharhinus Iimbatus F M M395 Carcharhinus Iimbatus M M M395 Carcharhinus limbatus F M M395 Carcharhinus Iimbatus M M M395 Carcharhinus Iimbatus F M M395 Carcharhinus Iimbatus M M M395 Carcharhinus Iimbatus F M M395 Carcharhinus limbatus F M M396 Carcharhinus Iimbatus M M M397 Carcharhinus limbatus F M M397 Carcharhinus Iimbatus F M M397 Carcharhinus limbatus M M M398 Carcharhinus Iimbatus F M M398 Carcharhinus limbatus F M M398 Carcharhinus limbatus F M M399 Carcharhinus Iimbatus M f -- M M399 Carcharhinus Iimbatus M t -; M M400 Carcharhinus Iimbatus M M M400 Carcharhinus Iimbatus M M M402 Carcharhinus Iimbatus F M M403 Carcharhinus limbatus M M M403 Carcharhinus limbatus F M M403 Carcharhinus Iimbatus M M M403 Carcharhinus limbatus M M M404 Carcharhinus Iimbatus M M

13 M406 Carcharhinus limbatus M 47 M406 Carcharhinus limbatus M 45 M406 Carcharhinus limbatus F 40 M406 Carcharhinus limbatus F 44 M407 Carcharhinus limbatus F 41 M407 Carcharhinus limbatus M 41 M407 Carcharhinus limbatus F 43 M407 Carcharhinus limbatus M 44 M407 Carcharhinus limbatus M 43 M407 Carcharhinus limbatus F 42 M407 Carcharhinus limbatus 46 M407 Carcharhinus limbatus M 43 M407 Carcharhinus limbatus M M M M M M M M M M M M Peterson Mark-Recapture Study: Sampling Effort 1: Sharks Caught = 180 Sharks Tagged = 159 Sampling Effort 2: Sharks Caught 102 Sharks Tagged = 91 Recaptures from Effort 1 = 11 (2 of which were recaptured twice) Population Size = (Number Tagged in Effort 1) X (Number Caught in Effort 2) Number of Tag Recaps from Effort 1 = (159 X 102) / 11 = 1,474 pups (compared to 934 estimated in 2000) This estimate requires refining (e.g. immediate post-release mortality from release condition needs to be estimated and incorporated into the analysis) for scientific publication. However, in general with the 2000 and 2001 estimates, it appears that somewhere around 1,000 blacktip pups use Yalahau Lagoon as a pupping and primary nursery area. Refinement of this figure will allow us to estimate the potential productivity of such areas and understand the importance of these essential habitats for rebuilding depleted shark populations. Bycatch: All vertebrate bycatch was measured (FL or OW in cm) and/or counted for all sets performed. There were 37 species documented encompassing 34 teleost, 2 ray, and 1 sea turtle species (Table 2). 11

14 Table 2. Bycatch captured during Yalahau field collections, 2001 Common name Scientific name N Min FL (cm) Max FL (cm) Bream Sea Archosargus rhomboidalis Croaker, Atlantic Micropogonias undulatus Catfish, Gafftopsail Bagre marinus Sailors Choice Haemulon parrai Jack, Crevalle Caranx hippos Grunt, White Haemulon plumieri Snook Centropomus undecimalis Sheepshead Archosargus probatocephalus Hogfish Lachno/aimus maximus Pompano Trachinotus carolinus Cowfish, Scrawled Lactophrys quadricomis Permit Trachinotus falcatus Snapper, Cubera Lutjanus cyanopterus Bluefish Pomatomus sa/tatrix Guitarfish, Atlantic Rhinobatos lentiginosus Burrfish, Striped Chilomycterus schoepfi Catfish, Hardhead Arius felis Seatrout, Spotted Cvnoscion nebulosus Ladyfish E/ops saurus Spadefish Chaetodipterus faber Bumper Chloroscombrus chrvsurus Cobia Rachvcentron canadum Filefish Balistidae Filefish, Unicorn Aluterus monoceros Flounder, Gulf Paralichthvs albigutta Jack, Horse-e-.e Caranx latus Kingfish, Southern Menticirrhus americanus Leathe~acket Oligoplites saurus Lookdown Selene vomer Mackerel, Spanish Scomberomorus maculatus Mojarra Gerreidae Pigfish Orthopristis chrysoptera Ray, Spotted Eagle Aetobatus narinari Sea Turtle, Green Chelonia mvdas Searobin Prionotus spp Snapper, Mutton Lutjanus analis Tripletail Lobotes surinamensis Fin Clips: A total of75 fin clips were collected from neonate and YOY blacktips. These will be utilized by geneticist Dr. Ed Heist, Southern Illinois University, and his graduate students in collaborative studies to determine the population differences of Mexican vs. U.S. sharks. 12

15 Recaptures from Previous Years: A total of 71 tags from recaptured sharks were recovered during this trip. The majority were from last year's tagging (67) but a few were from 1998 (4) and 1996 (1). Unfortunately, there were few usable data associated with these older recaptures so we could not confirm whether these sharks returned to the lagoon to be recaptured or were merely the result of tags that had been kept in hand for years. This unprecedented number of recaps came from only seven fishermen (or at least reported from only seven). In general, the data from many of these recaptures were extremely poor or in several cases, clearly fraudulent. The obvious explanation for this is that many of these fishermen caught the sharks while fishing illegally inside the lagoon (which is supposed to be off-limits to the net fishermen in the spring and summer), undoubtedly soon after we completed ourtagging last year. Consequently, only half rewards were paid where the data were clearly doubtful. It was explained to our contracted fishermen (and to the rest of the fishermen through them) that we would no longer pay rewards for recovered tags as a direct result of the poor data quality and underlying fact that our reward system may be providing incentive for fishermen to illegally fish the lagoon. This was further explained to the local PESCA official in Holbox (Eduardo Fuentes Rosel) so that he could further spread the word. This decision was met with no outward reservations or resentment from either the fishermen or the PESCA official. Meeting with Yalahau Environmental Group: While in Holbox, the CSR group was contacted by the director of Yum Salam (Jose Francisco Remolina), a Mexican environmental activist group involved in protecting the flora and fauna of various environmentally sensitive regions, with Yalahau being one of them. At a meeting with this group, a considerable amount of time was spent explaining to them the goals of this project. This group was genuinely interested in our research, but our impression was that they would have preferred to have been notified of our work in Yalahau in advance. They are concerned with the shark resource and would like to be able to work in conjunction with us to potentially invoke improved regulations and enforcement in and around Yalahau. We provided some information as to the times of the year when the shark resource in Yalahau would be most vulnerable to fishing effort. It was explained that we would be open to working together with Yum Salam but it would require permission of the INP and CSR directors. Further Observations: In previous years, we have noted evidence of a large shark fishery (carcasses, etc.) operating out of the north end of Holbox, but in general, this fishery has appeared to be much less active than it was in the early 1990's and before. Last year, our fishermen claimed that this fishery (using longlines) is landing significant numbers of large sharks including blacktips. This year we observed that there were 20 or more boats baiting up in preparation to apparently catch large fish. On one particular day, we observed a couple of large sharks being loaded into trucks, at least one of which was a large dusky shark, Carcharhinus obscurus (Fig. 4). 13

16 Figure 4. Large dusky shark at Holbox fish house. Since 1995, this project has collected data on 1,369 neonate and yay blacktip pups (Table 3). Recapture rate of tagged sharks has averaged 17.7%, which is about five times higher than the recapture rate of tagged sharks in U.S. waters, indicating very heavy fishing pressure on the young sharks in Mexico. Table 3. Summary CSRlINP blacktip tagging project activities in Yalahau, Number of Blacktips Blacktips Number of Recapture Year, Gillnet Sets Caught Tagged Recaptures Percent (%) Totals 390 1,369 1, b. Field Research in Western Gulf of Mexico To continue shark tagging studies in the western Gulf to assess exchange rate of sharks between U.S. and Mexican waters, a field trip was conducted November 13-20, 2000 to Matamoros, Mexico. This trip, again with collaborators from Mexico's INP, had the following objectives: 14

17 1) Collect any recaptured tags, collect associated data, and pay tag rewards; 2) Collect fin clips from YOY blacktips for population genetic studies; 3) Hire local fishermen to catch sharks, particularly YOY blacktips, to facilitate tagging; 4) Promote the tagging program in the fishing communities of Bagdad Beach and EI Mezquital, Mexico, by conversing with fishermen, hanging posters, and gaining the support of Pesca officials in Matamoros. Results of this trip are summarized as follows: Tag Recaptures: Five tags were recovered with three being Mote tags (spinner, blacktip, finetooth) and two being NMFS tags (both bull sharks). Two of the Mote tags were recovered in EI Mezquital while the other was found in Playa Bagdad. All Mote tags were from sharks originally tagged in Corpus Christi. Many people reported seeing NMFS tags in the past but most had thrown them away for one reason or another. One Mote tag was also reportedly thrown away. Efforts are underway to educate the fishermen about returning tags. Biological Data: The shark catches observed at Bagdad Beach on Nov comprised seven species including blacktip, Atlantic sharpnose, bull, sandbar, blacknose, finetooth, and smalltail. Sharpnose and blacktip made up about 98% of the catch (in equal proportions) while the other species were each represented by only a few individuals. All of the mature female sharpnose were pregnant and the observed embryos ranged in TL from 18.1 to 31.1 cm. Only one sandbar shark was observed but it was a mature female (230 cm STL). Fin clips were taken from 29 YOY blacktips for genetic analysis (Table 4). Additionallly, fin clip samples were taken from six bonnethead sharks for collaborative population genetic studies being conducted by Dr. Mahmood Shivji, Nova University. In addition to the work in Matamoros, Mexico in fall 2000, CSR scientists continued to work with sportfishermen along the Texas coast to tag sharks for studies of migration and exchange rate. A select group of trained fishermen are using CSR shark tags to tag sharks in Texas coastal waters, to extend CSR tagging efforts to the northwestern Gulf. In , 51 rod & reel trips (Table 5) resulted in the tagging of 168 sharks comprising six species (spinner, finetboth, bull, blacktip, sandbar and scalloped hammerhead) (Table 6). This effort continues to be a worthwhile activity to increase research efforts in the western Gulf and promote conservation-oriented practices among Texas sportfishermen. Table 4. YOY blacktip fin clips for genetic analysis from Bagdad Beach, Mexico, Sample # Sex pel (em) Fl(cm) Tl(cm) STl(cm) location 256 F km offshore 258 M km offshore 261 M km offshore 286 F km offshore 287 F km offshore 288 M km offshore 15

18 289 F km offshore 290 F km offshore 292 M km offshore 293 F km offshore 294 M km offshore 371 M km offshore 372 M km offshore 373 F km offshore 374 F km offshore 374 M km offshore 375 F km offshore 376 F km offshore 377 F km offshore 378 F km offshore 380 F km offshore 381 M km offshore 382 F km offshore 383 F km offshore 384 F km offshore 385 M km offshore 386 M km offshore 387 M km offshore 388 M km offshore Table 5. Rod & reel sample dates and locations of Texas sportfishermen, Sample # Mo Da Yr Location Latitude Longitude Depth (ft.) Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Port Arthur-8mi SSE of Port Arthur 29'31.526N 93'49.623W Port Arthur mi SSE of Port Arthur 29'29.457N 93'48.060W Port Arthur- Oil Rig 8 miles SSE of Port Arthur 29'31.640N 93'49.220W Corpus Christi-Bob Hall Pier Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Co_rpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97' ~ 2. 98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'1!.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'1298W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier Padre Is. 27'34.86N 97'12.98W 15 16

19 Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 9T12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 9T12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Caldwell Pier, PI. Aransas 27'49.557N 97'03.034W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 9T12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W Corpus Christi-Bob Hall Pier, Padre Is. 27'34.86N 97'12.98W 15 Table 6. Sharks caught, recorded, tagged and released by Texas sportfishermen. (REPRO = reproductive state: 1 = neonate; 1.5 = 'OY; 2 = 1 + ~-old juvenile; 3 = adult) Sample # SCIENTIFIC NAME SEX REPRO. PCl (cm) STl(cm) TAG # CONDo 56 Carcharhinus limbatus M Sphyma lewini M Carcharhinus limbatus M Carcharhinus limbatus F Carcharhinus limbatus F Carcharhinus limbatus Carcharhinus brevipinna M Carcharhinus limbatus I F Carcharhinus limbatus F Carcharhinus brevi pinna M Carcharhinus brevipinna M Carcharhinus limbatus F Carcharhinus brevipinna F Carcharhinus limbatus M Carcharhinus limbatus F Carcharhinus limbatus F Carcharhinus limbatus F Carcharhinus limbatus F

20 67 Carcharhinus limbatus F Carcharhinus isodon F Carcharhinus isodon F Carcharhinus isodon M Carcharhinus isodon F Carcharhinus isodon F Carcharhinus isodon F Carcharhinus isodon M Carcharhinus isodon F Carcharhinus limbatus M Carcharhinus limbatus M Carcharhinus isodon F Carcharhinus isodon F Carcharhinus limbatus F Carcharhinus isodon F Carcharhinus limbatus M Carcharhinus isodon M Carcharhinus limbatus F Carcharhinus isodon M Carcharhinus isodon M Carcharhinus limbatus M Carcharhinus isodon M Carcharhinus limbatus F Carcharhinus isodon F Carcharhinus limbatus M Carcharhinus isodon F Carcharhinus limbatus F Carcharhinus isodon F Carcharhinus limbatus F Carcharhinus isodon M Carcharhinus limbatus F Carcharhinus isodon M Carcharhinus limbatus F Carcharhinus limbatus F Carcharhinus limbatus F Carcharhinus limbatus F Carcharhinus limbatus F Carcharhinus limbatus F Carcharhinus limbatus M Carcharhinus limbatus F Carcharhinus limbatus F Carcharhinus limbatus M Carcharhinus limbatus M Carcharhinus limbatus F Carcharhinus limbatus M Carcharhinus isodon F Carcharhinus isodon F Carcharhinus limbatus M Carcharhinus limbatus F Carcharhinus isodon F Carcharhinus isodon M Carcharhinus limbatus F

21 74 Carcharhinus isodon M Carcharhinus limbatus F Carcharhinus limbatus M Carcharhinus limbatus M Carcharhinus isodon F Carcharhinus limbatus M Carcharhinus limbatus M Carcharhinus leucas M Carcharhinus isodon M Carcharhinus limbatus M Carcharhinus limbatus M Carcharhinus limbatus F Carcharhinus limbatus M Carcharhinus limbatus F Carcharhinus leucas F I Carcharhinus leucas M Carcharhinus limbatus F Carcharhinus limbatus F I Carcharhinus limbatus F Carcharhinus limbatus F Carcharhinus isodon F I Carcharhinus limbatus F I Carcharhinus limbatus F Carcharhinus limbatus F Carcharhinus limbatus F Carcharhinus limbatus F Carcharhinus limbatus F I Carcharhinus limbatus M Carcharhinus limbatus M Carcharhinus limbatus F Carcharhinus Jeucas F I Carcharhinus limbatus F Carcharhinus isodon F Carcharhinus plumbeus F Carcharhinus isodon F Carcharhinus plumbeus F I Carcharhinus plumbeus F Carcharhinus isodon M Carcharhinus limbatus F I Carcharhinus limbatus F Carcharhinus limbatus F Carcharhinus limbatus F Carcharhinus limbatus F Carcharhinus limbatus F Carcharhinus limbatus M I Carcharhinus limbatus M Carcharhinus limbatus M I Carcharhinus isodon M Carcharhinus limbatus F I Carcharhinus limbatus F Carcharhinus limbatus M Carcharhinus limbatus M

22 85 Carcharhinus Iimbatus F Carcharhinus limbatus M Carcharhinus limbatus M Carcharhinus Iimbatus M Carcharhinus Iimbatus M Carcharhinus Iimbatus M Carcharhinus Iimbatus M Carcharhinus limbatus F Carcharhinus Iimbatus F Carcharhinus limbatus F Carcharhinus limbatus F Carcharhinus Iimbatus M Carcharhinus limbatus M Carcharhinus Iimbatus F Carcharhinus limbatus F Carcharhinus limbatus F Carcharhinus limbatus M Carcharhinus limbatus M Carcharhinus limbatus F Carcharhinus Iimbatus F Carcharhinus Iimbatus F Carcharhinus Iimbatus M Sphyma lewini M Carcharhinus limbatus M Carcharhinus Iimbatus F Sphyma lewini M Sphyma lewini M Sphyma lewini F Carcharhinus Iimbatus F Sphyma lewini F Sphyma lewini F Carcharhinus Iimbatus F Sphyma lewini F Sphyma lewini M Carcharhinus Iimbatus F Sphyma lewini F Carcharhinus limbatus M Sphyma lewini F Carcharhinus Iimbatus M Carcharhinus limbatus M Carcharhinus Iimbatus F Carcharhinus Iimbatus F ! 1 96 Sphyma lewini M Sphyma lewini M Sphyma lewini M Carcharhinus Iimbatus F

23 c. Offshore Large Shark Surveys A fishery-independent survey using MML's RN Eugenie Clark (Fig. 5) was conducted in June 2001, to initiate deployment of archival and satellite tags (Fig. 6) on large shark species of interest. Up to 20 drum lines were set repeatedly for two nights (June 26 & 27) in waters directly off Sarasota, FL, ranging from 3-9 miles offshore. A total of 24 large sharks of five species (bull, tiger, lemon, blacktip and nurse) were caught, measured, tagged and released (Table 7). Figure 5.. MML's 50-ft coastal research vessel Eugenie Clark, used for large shark surveys and deployment of CSR electronic tags.. ~~-! '. Il' I! ~ 21

24 Figure 6. Satellite tag attached to dorsal fin of large blacktip shark. Table 7. Sharks caught, tagged, and released near Sarasota, FL on June 26/27 from the RN Eugenie Clark as part of the initial phase of new CSR studies of large sharks. SCIENTIFIC NAME PCl Fl Tl STL Mote Roto Tag Pup Tag ELECTRONIC SEX REPRO (em) (em) (em) (em) M-Tag t t t TAG CONDITION Carcharflinus leucas M T0244 R Carcharflinus leucas M T0039 R Galeocerdo cuvier F T0046 R Carcharflinus leucas F T0040 R Neqaprion brevirostris M T0050 R Negaprion brevirostris M T0037 R Negaprion brevirostris F T0042 R ~~_aprion brevirostris M T0032 R Carcharflinus leucas F T0235 R Carcharflinus Iimbatus F T0250 J Archival # Carcharflinus leucas M T0232 R Carcharflinus leucas F T0236 R Carcharflinus leucas M Carcharflinus limbatus M R0147 S Carcharflinus limbatus F J1007 S10356 Archival # Carcharflinus leucas M R Carcharflinus Iimbatus M Carcharflinus limbatus F R0184 S Carcharflinus limbatus F Carcharflinus leucas F T0245 R Carcharflinus leucas F T PAT-00P Ginglymostoma cirratum M Carcharflinus limbatus F J1006 S10359 PAT-00P Carcharflinus Iimbatus F R0186 S

25 The two archival (non-satellite) tags (Lotek L TD1 000) deployed on blacktip sharks were set up to record light levels (one measurement per minute), depth (1/min) and temperature (1/10 min). These tags must be physically retrieved for the data to be downloaded (no information as of the date ofthis report). The two pop-off archival satellite tags (PAT tags) were set to record light, depth and temperature every minute for three months (for the bull shark) or six months (for the blacktip), then pop off for data retrieval. The bull shark tag was retrieved prematurely, only about ten days after deployment (July 7), by a fisherman inside Tampa Bay near Egmont Key. The tag had apparently dislodged from its fin connection and was found floating on the surface. Five days of useful data were retrieved from the tag, and despite the very short period of recording, a diurnal pattern of depth changes by the shark is apparent (Fig. 7). Figure 7. Data recordings from PAT tag retrieved from large female bull shark, showing diurnal depth changes especially as sun sets at dusk (when light levels drop) and during the night. Each crest and trough in the light cycle is one 24-hr day. Note the dynamic depth changes in the 12+/- hrs after release, indicating a period of recovery behavior following the catch-and-release event. Bull shark g 140 ; 15 D- CD "' CD :; 5 IV... CD D- E 0 CD I ~ 'iii c 100 $.!: :E Cl 80 :::i L...JUL...o~~~~~~~~~~~~~~~~'-'-I -- Temperature (C) Time (record number 1 per minute) - Light level (R) 23

26 The PAT tag on the large female blacktip shark did not report data as programmed six months after tag deployment, in January Thus, the fate of this tag is unknown as of the filing of this report. These two initial disappointing results indicate that changes need to be made with the attachment method of the tags to the sharks. Such changes have been made and further testing and tag deployment are underway. In addition to the Florida Gulf surveys, a field trip to South Carolina was conducted in August 3-4, The purpose of this trip was to deploy internal archival tags in large sharks, preferably blacktips but other fisheries-relevant species were acceptable. This trip was made with Dr. Jose Castro of NMFS/SEFSC and utilized the services of commercial chark fishermen from the ar _a around the Bulls Bay coastline. Fishing was conducted by longline and gillnet in Bulls Bay and adjacent areas. Results were that two large female blacktip sharks were successfully implanted with archival tags and released, and the other eight sharks caught during the survey were tagged with conventional tags and released (Table 8). At least one of the archival-tagged blacktips survived the procedure because it was caught approx. one month later by a SC state biologist, who noted the tag type but released the shark without retrieving the tag. The other species tagged during the August survey were blacknose and sandbar sharks. Table 8. Results of August 3-4, 2000, pilot sampling trip off South Carolina. REPR SCIENTIFIC NAME SEX 0 PCL(cm) FL(cm) TL(cm) STL(cm) Pup Tag # NMFS Tag # Archival Tag # Location latl!ude Lonaltude CarchartJinus acronotus F Cape Romain 33 C..! 170N 79'19.038W Carcharhinus limba/us F Cape Romain 33'04.170N 79'19.038W Carcharhinus limba/us F Cape Romain 33'04.170N 79'19.038W Carcharhinus limba/us F Cape Romain 33'04.170N 79'19.038W Carcharhinus plumbeus F North Bulrs Bay - - Carcharhinus Dlumbeus F North Bulrs Bay - - Carcharhinus p/umbeus F North Bulrs Bay - - CarchartJinus plumbeus M North Bull's Bay - - Carcharhinus olumbeus M North Bull's Bay - - Carcharhinus plumbeus M North Bulrs Bay - - d. Fishery Ecosystem Modeling Development of an ecological model of the Charlotte Harbor system in SW Florida was begun using the ECOPATH with ECOSIM software. Development of this model requires the compilation of a large amount of data on all aspects of the ecosystem. Initial work on the model centered around the determination of species or species groups to include in the model. A total of 38 species/species groups (Table 9) was selected for the model based on the input of a range of scientists involved in studies within the areas. To assist in the development of the Charlotte Harbor model some data from a larger-scale model of the West Florida Shelf is being utilized. Dietary data from previous CSR studies in Charlotte Harbor have been used in the model to provide an understanding of the trophic interactions of elasmobranchs in the system. 24