National Shark Research Consortium
Florida Program for Shark Research - Florida Museum of Natural History
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NSRC-supported Initiatives
Studies of the age, growth, and reproduction of commercially important pelagic shark species
Due to their characteristic life cycles, shark populations tend to be highly vulnerable to fishing mortality.
In many parts of the world, sharks are caught in targeted fisheries or as bycatch. Large pelagic shark species
have recently become prized game fish in many countries. To conserve shark populations, fisheries managers require
updated and accurate life history data for the species caught in the fisheries. This project, part of a bi-lateral
research collaboration with scientists from the NMFS Southeast Fisheries Science Center and Brazil, involves the
gathering life history information on four species of shared pelagic sharks, the oceanic whitetip
(Carcharhinus longimanus), silky (C. falciformis), big eye thresher (Alopias supercilliosus),
and shortfin mako (Isurus oxyrinchus) in the Atlantic Ocean. The data from this study will
allow for comparisons between North and South Atlantic populations of these pelagic shark species and
provide needed life history data for stock assessments.
Studies of the age, growth, and reproduction of coastal elasmobranch species
Age, growth, and reproduction of the smooth butterfly ray (Gymnura micura)
The smooth butterfly ray (Gymnura micura) is found in shallow coastal waters throughout the state
of Florida. It appears to be relatively common in two of the Florida Program for Shark Research's targeted
sampling localities in the Indian River Lagoon and in the northeastern Gulf of Mexico. Despite animalist
presence within shallow coastal waters of the southeastern United States, little is known about its life
history, movements, and migration. We are currently studying the age, growth, and reproductive biology of
G. micrura. Vertebral and reproductive samples are being collected during sampling activities in the Mosquito
Lagoon portion of the Indian River Lagoon system and the Cedar Key region of the Gulf of Mexico. Additional
samples are being collected by researchers from the NMFS Panama City laboratory. These samples will be used
to calculate growth curves, determine ages and sizes at maturity, and determine fecundity levels for
G. micrura within these regions. The ability to collect samples from both the Atlantic and Gulf coasts will
allow us to determine if there are differences in the growth rate, age structure, or reproductive parameters
of smooth butterfly rays found within these regions.
Paternity of the Atlantic Sharpnose shark (Rhizoprionodon terraenovae)
Parentage studies utilizing high resolution molecular markers have revealed that genetic polyandry is common,
even in species with internal fertilization that had traditionally been considered monogamous or polygynous.
Paternity analysis has only been conducted for a handful of shark species (e.g. C. plumbeus,
Sphyrna tiburo, Negaprion brevirostris, Ginglymostoma cirratum), some with low sample sizes
(Triakis scyllium). The majority of these studies have shown sharks to be largely polyandrous. However,
a study on the bonnethead shark, S. tiburo, showed this species' mating habits to be mostly monogamous.
Mating behavior in sharks may be plastic, depending on anthropogenic and natural factors and may vary by
locality. The sharpnose shark (Rhizoprionodon terraenovae) is commonly caught in the commercial shark
fishery as bycatch. Knowledge of the reproductive behavior of shark species impacted by fisheries is
needed to fully understand how population level fluctuations may contribute to shifts in mating systems.
In this study, DNA samples from pregnant sharpnose sharks and their embryos are being analyzed utilizing
microsatellite genetic techniques. The occurrence or absence of polyandrous mating will be determined.
Reproduction of two congener shark species (Sphyrna lewini, S. mokarran)
Scalloped (S. lewini) and great (S. mokarran) hammerhead shark populations have been declining in the northwest
Atlantic Ocean and Gulf of Mexico. To better manage these shark populations, fisheries managers need accurate
species specific life history data. While recent age and growth studies conducted by FPSR and NMFS personnel
have helped to improve the accuracy of species specific stock assessments, there is still a need for updated
or novel reproductive data for these species. To date no study has provided accurate data on the reproduction
of the scalloped hammerhead in coastal eastern U.S. waters. Further, no comprehensive study on the reproduction
of the great hammerhead has been published for any population.
Biologist at the FPSR are 1) determining the size/age of maturity of male and female scalloped hammerhead and great
hammerhead sharks in the northwest Atlantic Ocean; 2) determining the fecundity and reproductive cycle for scalloped
hammerhead and great hammerhead sharks; 3) determining if female scalloped and great hammerhead sharks reproduce
annually or biennially; 4) determining if significant differences in reproductive parameters occur between these
two congeners. These data will allow for more accurate stock assessment models for populations of hammerheads in the northwestern
Atlantic Ocean and Gulf of Mexico.
Reproduction of the sandbar shark (Carcharhinus plumbeus)
The sandbar shark, Carcharhinus plumbeus, is a member of one of the largest and most commercially important
shark families (Carcharhinidae). This species is widely distributed in tropical and subtropical regions of
the Pacific, Indian, and Atlantic Oceans, as well as the Mediterranean Sea. In North American waters,
C. plumbeus ranges from Cape Cod to Florida, throughout the Gulf of Mexico, and around Hawaii.
The sandbar shark has historically been a key species in commercial shark fisheries along the U.S. East
coast. As shark fin soup is the main drive for the commercial shark fishing industry, this species is highly
sought after for its large fins. In recent years, sandbar sharks have been heavily fished in the northwestern
Atlantic, representing 35.9% of the targeted catch in the coastal bottom long-line shark fishery. Additionally,
a study has shown this species to comprise approximately 20% of the large shark fauna and is second only to the
blue shark, Prionace glauca, in recreational catches along the U.S. east coast. Despite current fishery
management strategies, recent stock assessments have shown that sandbar shark populations along the U.S. East
coast have greatly declined. National Marine Fisheries Service (NMFS) scientists have deemed the sandbar shark
as over fished.
This decline in sandbar shark populations reinforces the need for improved data on the biology of commercially
important shark species. More accurate assessment models, developed with updated life history data (age, growth,
and reproduction), will allow fisheries managers to establish more reliable catch quotas to ensure future
sustainability of the fishery. To this end, FPSR scientists are studying the reproductive biology of the
sandbar shark in the northwestern Atlantic Ocean and Gulf of Mexico. This study is focused on characterizing
reproductive parameters including the size of maturity, fecundity, length of gestation, timing of reproductive
events, and how often mature female sandbar sharks reproduce. These data allow for estimation of reproductive
output, a parameter used in assessment models.
Sharks specimens used in this study are obtained through fishery-dependent and -independent sampling utilizing
bottom long-line fishing gear. Upon capture, sharks are measured for fork length, total length and clasper lengths,
and the sex of the specimen is recorded. Gonads and genital ducts are dissected in the field and preserved for later
analysis. Clasper length data is used to determine the size of maturity for male sharks. Increases in nidamental
gland width and the condition of the uterus are used to determine the sizes of maturity for female sharks.
Variation in the sizes of the gonads and genital ducts are used to assess the seasonality of reproduction
and to determine the timing of reproductive events such as egg development, ovulation, sperm development and gestation.
Habitat use and behavioral ecology of elasmobranch species
Tagging and sonic tracking of elasmobranchs in the Indian River Lagoon
In cooperation with Dynamac, Inc. at the Kennedy Space Center, we currently maintain a passive acoustic
monitoring system that includes 43 moored receiving stations (Vemco VR2 and VR2W receivers) placed at key
locations throughout the northern IRL. The system monitors the movements of bluntnose stingrays
(Dasyatis say), smooth butterfly rays (Gymnura micrura), spotted eagle rays (Aetobatus narinari),
cownose rays (Rhinoptera bonasus), and bull sharks (Charcharhinus leucas).
Various other species of fishes and sea turtles are tracked within the array as part of Dynamac, Inc,
initiatives. Data from this study will indicate the seasonal habitat use of rays and juvenile bull
sharks within the Indian River Lagoon. We will develop Essential Fish Habitat parameters for elasmobranchs
in this region. In addition possible anthropogenic factors that may influence elasmobranch behavior will be examined.
Shark nursery delineation in the northeastern Gulf of Mexico
The Cedar Key area of the Gulf of Mexico consists of several small islands situated just offshore between the Suwannee
River mouth to the northwest and the Waccassasa River mouth to the southeast. This area encompasses many diverse
marine habitats including sea grass beds, mangroves, mud flats, oyster bars, tidal channels, and salt marshes.
The incidental capture of numerous elasmobranch species within this area off the western Florida coast by
scientists working for the University of Florida and the Florida Fish and Wildlife Conservation Commission
indicates this region may support a diverse and abundant assemblage of sharks and rays. Recent work suggests
that blacktip sharks, Atlantic sharpnose sharks, bonnethead sharks, smooth butterfly rays, cownose rays,
southern stingrays, bluntnose stingrays, and Atlantic stingrays all commonly occur within this region. Little
is known about the life history and ecology of many of these species, particularly the ray populations within
this region. Nursery areas are thought to enhance survivorship of neonate and juvenile sharks due to the presence
of increased resources and a lack of large predators. These areas tend to be closer to land and more vulnerable
to pollution and environmental disturbances making the identification and conservation of nursery habitat critical
to the health of shark populations.
In cooperation with NMFS Southeast Fishery Science Center we are continuing to monitor sharks and rays within
the Cedar Key area in the Gulf of Mexico using standardized gillnetting gear. Areas from the Waccassasa River
mouth to the Suwannee River mouth are being sampled using stratified random sampling techniques. This will
allow us to determine if this area functions as a nursery and Essential Fish Habitat for several elasmobranch
species. The use of gear consistent with that used to study elasmobranch nursery areas in the western Gulf of
Mexico and along the southern Gulf coast of Florida will allow us to compare the productivity of this area with
nearby areas. To date this area of the Gulf of Mexico is largely unstudied and represents a significant gap in
our knowledge of elasmobranch species within the Gulf of Mexico.
Smalltooth Sawfish tagging in Keys
The smalltooth sawfish (Pristis pectinata) is the only marine fish to be listed on the endangered
species list in U.S. waters. Sawfish have undergone large declines during the past 50 years. The Sawfish
Recovery Plan calls for the determination habit use by the smalltooth sawfish and their movement patterns
therein. In collaboration with scientists at NMFS Panama City, this project aims to learn more about the
habitat preference and movements of sawfish through satellite telemetry. Satellite tags will be placed on
adult smalltooth sawfish (Pristis pectinata) within Florida waters. These tags record data on depth,
temperature, and light levels. The data from the tags are then transmitted to satellites operated by
ARGOS which are then transmitted to the researcher via email. Results from this work will elucidate
habitat and seasonal movements of adult sawfish as well as determination of critical habitat within
Florida waters. In addition, these tags will provide insight into any possible post-release mortality
of sawfish captured via recreational angling gear.
Genetic analysis of elasmobranchs in the northwestern Atlantic Ocean and Gulf of Mexico
Population genetics of the Blacknose shark (Carcharhinus acronotus)
The blacknose shark (Carcharhinus acronotus) is a small coastal shark species commonly found in
the northwest Atlantic Ocean and Gulf of Mexico. While currently not a targeted species in
commercial fisheries, its frequent capture in current commercial and sport fisheries and the
possibility that federally mandated reductions in the allowable catches of overexploited large
coastal sharks may shift fishing pressure to this species. To this end, advances in our knowledge
of blacknose shark biology are required. Previous reproductive studies have not been in agreement
on the periodicity of reproductive events. A study on the reproduction of blacknose sharks in the
northwestern Atlantic indicated a biennial reproductive cycle. By contrast, a recent study on
blacknose sharks in the Gulf of Mexico showed an annual reproductive cycle. The objective of
this project is to determine if these variations in reproductive seasonality have a genetic basis.
Results from this project will aid in future stock assessments through delineating causes for
variation in reproductive seasonality.
Population genetics of batoids from the East and West coasts of Florida
Little is known regarding batoid (skates and rays) population dynamics and stock structure on the east
and west coasts of Florida. Given the lack of knowledge and possibility of emergent fisheries for species
of batoids, it is extremely important to determine population structure and abundance estimates for
management purposes. Genetic analysis is one method in which population segments may be defined. We
will use this methodology to determine if contiguous populations exist between the Florida Gulf and
Florida Atlantic Coast regions. We are collecting tissue samples from butterfly rays (Gymnura micrura),
bluntnose rays (Dasyatis say), southern rays (D. americana), cownose rays (Rhinoptera bonasus), and
spotted eagle rays (Aetobatus narinari) from the Cedar Key and Indian River Lagoon regions for these
analyses. Samples will be stored in 95% ethanol until genetic sequencing is conducted. These data
will provide better understanding of migratory and population patterns of these ray species.
Taxonomy of the genus Centrophorus
In the face of dwindling shark numbers, shark taxonomy is becoming more important as scientists attempt to
identify species in order to explain the subtle relationships and complex reactions of ecosystems threatened
by human activities. The study of taxonomy provides a solid foundation for the research needed for the
conservation of sharks and their habitat. Taxonomists recognize that the genus Centrophorus is in need
of revision, as examination of Centrophorus literature reveals that much taxonomic uncertainty exists. A
paucity of material and lack of data on developmental changes have resulted in wide differences of opinion
about the validity of the species assigned to Centrophorus. Researchers differ in the choice of morphometric
and meristic characters used as diagnostic features for the species. Coloration, placoid scale variation,
and tooth configuration have all been used as diagnostic features of the genus in the past.
Morphometrics of the genus Centrophorus from the Northwest Atlantic Ocean have been analyzed in an effort
to determine species validity. Initially, Discriminant Function Analysis (DFA) was performed using 65
morphological measurements of 59 museum specimens and 25 newly caught specimens from Jamaican waters.
The key characters separating these 84 specimens are associated with snout length, pelvic fin inner margin
length, length of the subterminal margin, and length of the caudal fin. The DFA supports the validity of
Centrophorus acus, C. granulosus, C. uyato, and a C. sp. Recently, morphometrics of twelve
specimens (provided by Jose Castro of NMFS and Mote Marine Laboratory), also collected from the Northwest
Atlantic, were compared with results from the analysis of the initial 84 specimens. A
comparison of all 96 Centrophorus specimens, using the 12 most diagnostic measurements, will be completed
during this study. A DNA analysis between these specimens is also being conducted. Future work will focus on collecting
morphometrics from more Centrophorus specimens. This database will serve as a valuable tool
for Centrophorus comparison and identification.
Age-structured simulation model for the dusky shark (Carcharhinus obscurus)
The current Federal Fishery Management Plan for Atlantic sharks manages 39 species, which are separated into three management
categories: large coastal (ridgeback and non-ridgeback), small coastal and pelagic sharks. In 1999, 14 of these species
were moved to the prohibited species list, including the dusky shark. Commercial and recreational fishermen are no
longer allowed to land this species. Despite this change in management, dusky shark populations continue to remain
low due to intrinsic biological characteristics and high at-vessel mortality.
For this project, two separate population models for the dusky shark were developed. The first model was age
structured to determine the status of this population now and in the future. Data for this model included
biological information, mortality rates, catches and catch rates. A base case scenario and several sensitivity
analyses were conducted. The base case incorporated catches and catch rates through 2006, current fishing and
natural mortality, and known biological information while the sensitivity analysis examined alternative scenarios
such as no fishing mortality, area closures, reducing the number of discards and increasing fishing pressure.
The second model was a spatially stage structured model to look at the effects of time/area closures on the
population of the dusky shark. Movement rates, virgin recruitment, natural and fishing mortality and spatial
cells were used in this model. A base case and several sensitivity analyses were conducted using this model.
The base case included the current time/area closure, which exists off the coast of North Carolina, current
mortality rates and estimates of this species movement rates and virgin recruitment. Sensitivity runs
examined both larger and smaller closures, different mortality rates, movement rates and virgin recruitment
size. This project was recently completed with the results being submitted for publication.
Maintenance and growth of the International Shark Attack File (ISAF) and public education about shark attacks
The ISAF is a cooperative program administered by the American Elasmobranch Society and the Florida Museum of
Natural History at the University of Florida. It is the international repository of scientific data on shark
attacks, having served in that capacity since 1958. Approximately one hundred new cases are added each year
and many older case files are modified by additions of new or altered data. The ISAF currently houses 4,506
cases. ISAF personnel coordinate the activities of a network of U.S. and international scientific cooperators
who investigate attacks in their regions and forward their investigative data to the ISAF. Because more than
two-thirds of the world's yearly attacks occur in U.S. and nearby waters, most investigations are conducted by
ISAF personnel. The ISAF staff analyzes the database for short- and long-term trends, and recommends strategies
to reduce the risk of attack to federal, state, and international governmental agencies. In addition, each year
the ISAF staff responds to hundreds of inquiries from the media and general public about the subject, and take
part in several shark education programs. Since shark attack, shark fishery management, and shark conservation
have increasingly become interrelated topics, responses to these queries serve to further a broad understanding
of shark-related issues in the public at large.
We are continuing our effort to create a new ISAF database. A new volunteer database
programmer is also assisting with this task. The new database will have a web interface for presentation of summary
analyses and will run through Microsoft Sequel Server. The new database will provide a standardized data
entry format and be more user friendly than the current Microsoft Access database. In addition, we will be
able to upload video, pictures, ISAF questionnaires, medical files and newspaper articles into the expanded
database. Other initiatives for this proposal include rechecking all the case files, following up on open
case files and continuing the documentation of all new shark attacks worldwide. A case study of Volusia
County, FL (which annually has more attacks than any other area of similar size) shark incidents will also
be conducted.
Web- and media-based public education focusing on shark biology, ecology, management, and conservation
The shark section of the Florida Museum of Natural History's Ichthyology web
site [http://www.flmnh.ufl.edu/fish/Sharks/sharks.htm] provides a rich source of
information on sharks as well as other elasmobranchs and is the most highly utilized shark site on the
World Wide Web. In addition to disseminating information on the Museum's own programs (FPSR and ISAF)
and sharks in general, the site hosts the web pages of the Smalltooth Sawfish Recovery Team, a group
working to restore this endangered species to former levels of abundance. The ISAF pages are the site's
most highly utilized pages owing to the public and media's almost insatiable interest in shark attacks.
Viewers drawn to the site by fascination with shark attacks find complementary explanatory material
dealing with shark biology and ecology, conservation, and fishery management. In addition, the site
also includes informational pages focusing on sawfishes, spiny dogfishes, and white, whale, basking,
and megamouth sharks; current shark news items; educational information and activities; organizational
information; reference and resource lists; announcements for meetings and conferences on sharks; and
links to other shark-related sites. The result is that interested viewers come away with a more
balanced view of elasmobranchs and measures needed to insure their management and survival. We have
found that providing a combination of web-based educational materials plus direct interplay with the
media results in a very positive approach to educating the public about elasmobranch issues.
We are continuing to add new information and features oriented to public
education on sharks, sawfish, skates, and rays. The shark attack statistics on the ISAF statistical
pages will continue to be updated frequently due to the high degree of interest with new information
added as it becomes available. Biological profiles of individual species of elasmobranchs represent
one of the most important common threads between various sections of the web site, linking photographs
in the Image Gallery, a major entry page of the site, to virtually all shark sections. These profiles
provide summary information on the life history, distribution, ecology, behavior, and conservation/management
status of each species. To date, we have a total of over 120 elasmobranch profiles available online to which
we will continually add new species. The interactive educational component of the web site is continually
updated and improved. Additions include development of innovative teaching materials in the form of
teaching modules that will cover various aspects of shark, ray, and sawfish biology and conservation.
These online teaching modules will be accessible by educators throughout the country as well as worldwide
via our web site. In addition, an online exhibit consisting of a shark dissection and shark anatomy along
with teaching materials is being created and will become available in the education section of the web site.
Also, ongoing maintenance activities will include every section of the shark web site including
organizational information, news stories, image gallery, education, conferences and meetings, staff,
outside links, and references. Finally, we are also optimizing the web pages for popular search engines such as Google,
so that users searching for information on sharks (etc.) can more easily find and access this information on our site.
Web- and media-based public education focusing on sawfish biology, conservation and reporting of encounters
The National Sawfish Encounter Database (NSED) was recently transferred to the Florida Program for Shark Research
(FPSR) at the Florida Museum of Natural History (FLMNH). Formally housed at Mote Marine Laboratory, the NSED is
currently integrating the Mote database with five other sawfish databases: one from the FLMNH, two from the Florida
Fish and Wildlife Conservation Commission, and two more databases from private sawfish aficionados. As a result, all
existing information regarding U.S. smalltooth sawfish will be held in one place (FLMNH) under the NSED. Therefore,
the FPSR is handling all future sawfish encounter reports.
The information from the sawfish encounter reports is entered into the database and used for monitoring the smalltooth
sawfish population. This information assists in the evaluation of the species abundance and habitat range, helping
the sawfish recovery team not only to estimate the population size but also to identify their habitat preferences.
This type of information is vital for the recovery of the U.S. smalltooth sawfish population, and greatly assists
in conservation efforts. In addition to research, the NSED data is used for answering inquiries related to environmental
impact planning/permitting as the smalltooth sawfish is protected under the Endangered Species Act.
Since September 2008, the FPSR has been focusing on integrating the six different databases into one functional
database, answering inquiries and increasing public awareness. One of the main objectives of the FPSR is to inform
the public about the NSED transfer from Mote Marine Lab to the FLMNH. In the last past months, the FPSR gave several
interviews both to local and national newspapers, as well as radio and television. We have also developed a new
sawfish website located at http://www.flmnh.ufl.edu/fish/sharks/sawfish/. All interviews and the website have
have been focused on sawfish conservation, the importance of reporting sawfish encounters, and new NSED contact information.
We expect in the future the number of reports will rise rapidly as we increase public outreach efforts.
Classroom-based elasmobranch education initiatives
Project Shark Awareness
Project Shark Awareness Student
Photo credit: Matthew Ratajczak
Scripps Treasure Coast Newspapers
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Project Shark Awareness is a classroom-based outreach program for educating school teachers and other educators about
the myths and realities of shark behavior, biology, and conservation. This program consists of a series of workshops
and training sessions augmented by a variety of teaching support materials. A teaching kit consisting of a PowerPoint
presentation, teaching guide, handouts, methods to evaluate student learning (quiz, puzzles, question sheets) is
provided to educators for use in their classrooms. In addition, shark jaws, teeth, and skin in the teaching kits
will provide hands-on learning opportunities. A companion web page within the FLMNH Ichthyology education web site
is available online to accompany Project Shark Awareness materials.
Due to the overwhelming response to the workshops held in previous years. We are hoping to expand this outreach effort to
include workshops for educators throughout the southeast United States during this time period. This effort will
be dependent upon gaining external funding through alternative granting sources. Currently we have three
proposals submitted for review in support of this education initiative.
Sawfish In Peril
Sawfish in Peril is a new classroom-based education initiative which will be designed and implemented
in a similar manner to Project Shark Awareness. Very little is known about sawfishes, which historically
were common in tropical and subtropical waters. Historic records indicate that smalltooth sawfish
(Pristis pectinata) previously inhabited coastal waters as far north as New York. Today, the U.S.
distribution of the smalltooth sawfish is primarily restricted to the waters off the coast of southwest
Florida. Although it is difficult to estimate the exact numbers of sawfish remaining in U.S. waters, it
is likely that the population has declined at least 95% over the past century. As a result, the smalltooth
sawfish has recently been listed for protection under the U.S. Endangered Species Act. The
largetooth sawfish (Pristis perotteti), once found in low numbers in waters from Texas to Florida,
likely has been extirpated from U.S. waters. Sawfish In Peril will result in a better-informed public
concerning the plight and protection of sawfishes native to U.S. coastal waters, as well as the fate of sawfishes
in general, which as a group are globally threatened. Workshops will be held for Florida educators dependent upon
external funding availability which is currently being pursued.
In addition to the above program, we are currently distributing brochures on smalltooth sawfish detailing
the conservation status as well as how to handle and release an accidentally captured sawfish. We are
continuing the distribution of these brochures through marinas and tackle shops along the
southwest coast of Florida as well as through educators in schools throughout the state. Also, sawfish
signage is continuing to be posted in cooperation with the Florida Fish and Wildlife Conservation
Commission at appropriate marinas and boat launches in southwest Florida. External funding is currently
being sought to assist with the continuation of our sawfish outreach initiatives.
Page updated January 29, 2009
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