Dana M. Bethea

NOAA Fisheries Southeast Fisheries Science Center · Panama City Laboratory

Understanding how interactions among microevolutionary forces generate genetic population structure of exploited species is vital to the implementation of management policies that facilitate persistence. Philopatry displayed by many coastal shark species can impact gene flow and facilitate selection, and has direct implications for the spatial scal...

We report 24 new records of the Brazilian cownose ray Rhinoptera brasiliensis outside its accepted geographic range. Sequencing of a 442‐base pair portion of the mitochondrial NADH dehydrogenase subunit 2 gene for 282 Rhinoptera samples revealed eight records off the east coast of the USA and 16 from the eastern Gulf of Mexico. Both sexes of all li...

The smalltooth sawfish Pristis pectinata is threatened with extinction throughout its range and has been designated as Critically Endangered by the IUCN. In the USA, the species historically ranged from Texas to North Carolina, but mortality in fisheries and habitat loss have reduced the range to primarily southwest Florida. The US population was l...

Highly productive, protected habitats have been shown to serve as nurseries for many marine fishes. However, few studies quantitatively measure the biotic characteristics that often drive a habitat's function as a nursery. We used a combination of passive acoustic monitoring and quantification of biotic attributes to assess nursery habitat use of j...

Similar to other elasmobranchs, the smalltooth sawfish Pristis pectinata is slow growing, matures late in life, and produces relatively few young, all factors that have contributed to its sensitivity to dramatic population declines from overfishing and habitat loss. Currently, the physiological stress response of these fish to capture or to other p...

Relative abundance of many shark species in the Atlantic is assessed by compiling data from several independently conducted, but somewhat spatially limited surveys. Although these localized surveys annually sample the same populations, resulting trends in yearly indices often conflict with one another, thereby hindering interpretation of abundance...

Patterns of population structure, genetic demographics, and gene flow in the small coastal shark Carcharhinus isodon (finetooth shark) sampled from two discrete nurseries along the southeastern U.S. coast (Atlantic) and three nurseries in the northern Gulf of Mexico (Gulf), were assessed using 16 nuclear-encoded microsatellites and 1077 base pairs...

Habitat use studies can be used to investigate ecological and behavioural patterns of animals and serve as useful tools for conservation planners. However, specific habitats essential to survival can be difficult to determine for highly mobile marine animals, especially when these species are rare or endangered. Active acoustic tracking telemetry w...

A re-assessment of the diet of the Atlantic sharpnose shark Rhizoprionodon terraenovae was conducted to provide an update on their trophic level. Rhizoprionodon terraenovae primarily consume teleosts, but previously unreported loggerhead sea turtles Caretta caretta were also found in the diet. Analysis suggests that calculated trophic level may dep...

Coastal shark abundance and community struc-ture was quantified across 10 geographic areas in the northeastern Gulf of Mexico using fishery-independent gillnet data from 2003 to 2011. A total of 3,205 sets were made in which 14,244 carcharhiniform sharks, primarily juveniles, were caught comprising 11 species from three families. The three most abu...

This update includes a correction to one of the citations. Vsn4 is the latest data.

The successful management of shark populations requires juvenile recruitment success. Thus, conservation initiatives now strive to include the protection of areas used by pre-adult sharks in order to promote juvenile survivorship. Many shark species use inshore areas for early life stages; however, species often segregate within sites to reduce com...

Several small scale fishery-independent gillnet surveys for coastal shark populations have been conducted in the Gulf of Mexico since 1995. These surveys were designed to determine shark nursery habitat and provide relative abundance indices as inputs to stock assessment models. Individually the relative abundance trends were limited both spatially...

Knowledge of relationships between predator size and prey size are needed to describe interactions of species and size classes in foodwebs.Most estimates of predator and prey sizes have been based on dietary studies and apply to small numbers of species in a relatively narrowsize range. These estimatesmay ormay not be representative of values for o...

Gillnet mesh selectivity parameters were estimated for juvenile blacktip sharks (Carcharhinus limbatus) by using length data from an experimental fishery-independent gillnet survey in the northeastern Gulf of Mexico. Length data for 1720 blacktip sharks were collected over 17 years (1994-2010) with seven mesh sizes ranging from 7.6 to 20.3 cm. Four...

Juvenile scalloped hammerhead sharks, Sphyrna lewini (Griffith and Smith, 1834), were collected in northwest Florida to examine foraging ecology, bioenergetics, and trophic level [30–60 cm fork length (FL); mean FL= 41.5 cm; N = 196]. Diet analysis was performed using single and compound measures of prey quantity, as well as seven broad diet catego...

Coastal habitat use and residency of a coastal bay by juvenile Atlantic sharpnose sharks, Rhizoprionodon terraenovae, were examined by acoustic monitoring, gillnet sampling, and conventional tag–recapture. Acoustic monitoring data were used to define the residency and movement patterns of sharks within Crooked Island Sound, Florida. Over 3years, sh...

Knowledge of relationships between predator size and prey size are needed to describe interactions of species and size classes in food webs.Most estimates of predator and prey sizes have been based on dietary studies and apply to small numbers of species in a relatively narrow size range. These estimatesmay ormay not be representative of values for...

To examine variation in diet and daily ration of the bonnethead shark, Sphyrna tiburo (Linnaeus 1758), animals were collected from three areas in the eastern Gulf of Mexico: northwest Florida (∼29°40′N, 85°13′W), Tampa Bay near Anclote Key (∼28°10′N, 82°42.5′W), and Florida Bay (∼24°50′N, 80°48′W) from March through September, 1998–2000. In each ar...

Atlantic sharpnose shark Rhizoprionodon terraenovae (Richardson, 1836) diet is described from Crooked Island Sound, an embayment of the northeast Gulf of Mexico. Diet was assessed by life-stage and quantified using six indices: percent by number, percent by weight, frequency of occurrence, the index of relative importance (IRI), IRI expressed on a...

Sharks may have an important role in marine ecosystems in relation to populations of fish and invertebrates at lower trophic levels. Fishery management plans stress the need for an ecosystem approach, but few quantitative studies on the foraging ecology of sharks have been published. Stomach contents and catch data of early life stages of Atlantic...

The life history and population dynamics of the finetooth shark (Carcharhinus isodon) in the northeastern Gulf of Mexico were studied by determining age, growth, size-at-maturity, natural mortality, productivity, and elasticity of vital rates of the population. The von Bertalanffy growth model was estimated as Lt=1559 mm TL (1-e-0.24 (t+2.07)) for...

Keywords: Resource partitioning, Predator-prey relationships, Habitat overlap, Diet overlap, Feeding Habits. System requirements: Adobe Acrobat reader. Mode of access: World Wide Web. Title from PDF t.p. (viewed on Aug. 21, 2004). Thesis (M.S.)--North Carolina State University, 2003. Includes bibliographical references (p. 88-94). Includes vita.