SEMI-ANNUAL PERFORMANCE REPORT Mote Marine Laboratory Technical Report No: 1082 Award Number: NA16FL2813 Amount of Award: Federal Share $ 1,825,929 Project Title: Highly Migratory Shark Fisheries Research by the National Shark Research Consortium (NSRC), 2005-2006 Recipient: Mote Marine Laboratory, Sarasota, Florida Award Period: July 1, 2005 to June 30, 2006 Period Covered by this Report: July 1, 2005 to December 31 , 2005 Primary Project Tasks: The following primary tasks were scheduled for this six-month period: Mote Marine Laboratory Component la. Shark life history, migration and stock structure 1b . Satellite tag testing and development lc. Navigation and orientation I d. Relative abundance Ie. Population and ecosystem I f. Freshwater habitat use 19. EFH environmental studies lh. Nurse shark reproduction I i. Whale shark research in the Gulf of Mexico and Caribbean Sea Ij. Publications and scientific conferences Moss Landing Marine Laboratories Component 1 2a. Eastern North Pacific chondrichthyan life history data matrix 2b. Age, growth, and demographic studies 2c. Age validation studies 2d. Reproductive biology 2e. Feeding ecology 2f. Stable isotope analysis 2g. Habitat associations and nursery grounds 2h. Population genetic studies 2i. Shelf, slope and pelagic surveys 2j. Eastern Pacific shark fisheries analysis 2k. Taxonomic studies 21. Publications/conferences Virginia Institute of Marine Science Component 3a. Relative abundance and distribution studies 3b. Age, growth, and demographic studies 3c. Habitat utilization and migration studies 3d. Shark energetic and osmoregulatory studies 3e. Shark genetics 3f. Publications and conferences University of Florida Component 4a. Fishery independent sampling 4b. Age, growth, and reproduction 4c. Skate life history 4d. Tagging/tracking 4e. Age-structured model 4f. International Shark Attack File 4g. Web/media education 4h. Classroom education 4i. Requests for information 4j . Publications and conferences Summary of Results: 2 General Project Overview Significant progress was made during this six-month period ofthe project. Important advances by the NSRC were made in both field and laboratory approaches to understanding the life history, abundance and environmental biology of shark species important in commercial and recreational fisheries. NSRC researchers and students continued to make significant scientific contributions through publications and conference presentations during the six-month period. There were no major problems experienced with the overall project during the period. Mote Marine Laboratory Report (R. Hueter, P/I) Mote's Center for Shark Research (CSR) served as project coordinator. No problems were encountered in the administration of the project. The following technical accomplishments were achieved during the reporting period: la. Shark life history, migration and stock structure. From July through December 2005, the Mote CSR captured a total of 175 sharks of 8 species. Of these sharks, 95 were tagged and released. During this same period, 22 recaptured sharks were reported and logged in the CSR <Jatabase. Of these, the longest at large was a bull shark (Carcharhinus leucas) tagged in October of2002 during CSR quarterly surveys off Longboat Key. It was recaptured in September of2005 after 1,083 days (2.97 yrs) at liberty, off Apalachicola, Florida, about 136 nm (252 km) from its original tagging site. The longest minimum at-sea distance traveled in these recaptures was reported from a juvenile blacktip shark tagged off Yankeetown, Florida in August of2004. This shark was recaptured in July of2005 off Broken Islands in Charlotte Harbor, Florida, about 149 nm (276 km) from its tagging site. Two surveys for large coastal sharks were undertaken during the period, one in fall (Sept 2005) and one in winter (Dec 2005) in the waters off Sarasota. The fall survey was conducted aboard the RIV Eugenie Clark and consisted of only 2 days of fishing due to a severe red tide outbreak (from the dinotlegellate Karenia brevis) in the area. This type of harmful algal bloom is known to have a significant impact on shark movement patterns. Consequently, no sharks were captured during the two days of fishing on this trip. The winter trip, which utilized the Florida Institute of Oceanography vessel RlV Suncoaster, also consisted of2 days oflongline and drumline sampling. This survey captured 19 sharks, comprising C. brevipinna (13), C. aero notus (4) and C. plumbeus (2). Several mechanical problems with the vessel shortened this trip's duration from 5 to 2 days. To further development a biomarker for bonnethead sharks (Sphyrna tiburo) exposed to estrogen-like pollutants, a total of 10 gill net sets were conducted to collect specimens of this species in the areas of Tampa Bay, Charlotte Harbor, Biscayne Bay, and the Florida Keys. · A total of92 sharks were captured comprising S. tiburo (78) and C. limbatus (14) with nearly half of these sharks being tagged and released. 3 lb. Satellite tag testing and development Tank-testing of satellite tags was not conducted during this period as the research tanks of Mote CSR's MERF (Marine Experimental Research Facility) were in use for other projects. However, field studies using PAT satellite tags continued. Wildlife Computers P AT tags were deployed on three species of shark during the study period - two whale sharks (Rhincodon typus) , one sawfish (Pristis clavata) and two blacktip sharks (Carcharhinus limbatus). All five tags released reported data to MML researchers. Results ofthe whale shark tags are described in a section below. The sawfish tagged demonstrated a high level of site fidelity, but depth data returned provided information on excursions from its regular home range. The tag from one of the two blacktip sharks was returned after washing up on a beach. This tag had detached from the shark after less than seven days. The other blacktip tag remained on the shark as programmed. The tag surfaced near Cuba and downloaded valuable data on movements of this species. The success of these tag deployments in light of previous difficulties indicates that the testing and development being undertaken with this project is providing increased effectiveness ofthis useful tagging methodology. Planned tank testing of satellite tag attachment and design should commence shortly as other experiments in the holding tanks have now been completed. lc. Navigation and orientation. Translocation studies to examine site and nursery area fidelity of juvenile blacktip sharks were successfully initiated in 2005. Six native sharks within Terra Ceia Bay were collected, held under transport conditions for 3 hours, fitted with acoustic transmitters and released in good condition. After the successful release of these individuals sharks were collected within Pine Island Sound and transported (3 hours) to Terra Ceia Bay. Eleven individuals were transported and nine were considered in good enough condition to fit with acoustic transmitters and release. All sharks were monitored via the acoustic monitoring network and none suffered mortality immediately post-release. Individual sharks showed varying movement patterns with translocated sharks tending to use more of the study site than native sharks. However, only two weeks of data were collected with all sharks present within the study site. At that point an extensive, intense red tide algal bloom moved into the study site causing large-scale morality of sharks, rays and teleosts. All individuals fitted with transmitters suffered mortality during this event and no further data were collected. Although data concerning residence and movement patterns were not useful, the initial results of this study suggest that this type ofproject can be successfully carried out and useful results obtained. ld. Relative abundance. During the period of this report, no blacktip relative abundance sets in primary nurseries were conducted as these field activties were suspended in 2005 due to concerns over high mortality of pups in the nursery as a result of red tide, as well as the direct effects of our own gillnet fishing. In lieu continued field work, a large-scale analysis of this project's 10-year dataset of three Florida Gulf coast nurseries (Yankeetown, lower Tampa Bay and Pine Island Sound) was conducted and its results presented at the annual American Elasmobranch Society Meeting, July 2005, in Tampa. Overall, 970 quantitative gill nets sets were made between 1995 and 2004 resulting in the capture of 8,257 sharks of thirteen species, of which 3,842 were juvenile blacktips. Recaptures have been reported from 151 of the tagged sharks comprising 5 species. First-year blacktips have demonstrated movements of more than 280 nautical miles after leaving their summer nursery grounds. Recapture data further indicates a pattern of sharks returning to their natal nursery areas the following season and in subsequent years. A general linear model was used to standardize the CPUE data. Significant differences in the juvenile blacktip catch were found between years, nursery areas, and between grids within a nursery area. When looking at the blacktip catch rates over the entire 1O-year period, there were no apparent trends that would be indicative of population 4 level changes despite stock assessments indicating an increasing abundance ofblacktip sharks in the U.S. Atlantic and Gulf of Mexico since the mid 1990s. The ability these surveys to detect changes in recruitment in the nursery areas may have been influenced by environmental