Sharks play a critical role in maintaining marine ecosystem resilience, yet many populations have declined due to overfishing and environmental change. In Texas, shark relative abundance trends across estuarine, nearshore, and offshore environments remain poorly understood. This study integrated three complementary fishery-independent surveys spanning ∼40 years (1983–2024), to improve understanding of cross-shelf shark assemblage structure and evaluate temporal and environmental drivers of relative abundance for 12 shark species, using Generalized Additive Mixed Models (GAMMs). This multi-dataset approach captured a broad range of environments and life stages, reducing bias associated with single-survey analyses. Of the 12 species examined, relative abundance of seven increased in at least one environment, three showed no directional change, and two declined consistently across environments. Blacktip Sharks (+149% [95% CI:101, 208] estuarine; +60% [95% CI:13, 125] offshore) and Bonnetheads (+481% [95% CI:366, 624] estuarine; +398% [95% CI:27, 1855] offshore) exhibited the most consistent multi-environment increases. Bull Sharks (+128% [95% CI:106, 154]) and Scalloped Hammerheads (+373% [95% CI:224, 591]) increased significantly in estuaries, while Great Hammerheads increased in nearshore waters. In contrast, Lemon Sharks showed the most severe decline (−99% [95% CI:−100, −98]) in estuaries, and Atlantic Sharpnose Sharks declined consistently across environments (estuarine: −65% [95% CI:−79, −41]; nearshore: −79% [95% CI:−88, −65]). Overall, these findings support reported increases in shark encounters by fishers, while also identifying species-specific declines that warrant concern. By establishing a unified baseline across environments, this study provides critical context for bycatch assessment and stock monitoring, and supports the development of adaptive, evidence-based shark management strategies in Texas waters.

Elasmobranch nurseries often differ in environmental conditions, demographics, and use patterns. These differences affect the distribution of genetic variation among nurseries. However, conservation and management strategies often fail to account for such differences because they are difficult to characterize. We assessed differences in connectivity, genetic variation, and numbers of breeders among scalloped hammerheads (Sphyrna lewini) sampled in five nurseries in the western North Atlantic Ocean. We used a reduced-representation genomic approach to genotype 472 young of the year and small juveniles at 8,334 loci containing single-nucleotide polymorphisms. We inferred full- and half-sibling relationships and used mitochondrial genome haplotypes to differentiate between maternally and paternally related half-siblings. Among 45 sibling pairs detected, 91% were from the same nurseries and only four pairs were sampled in different nurseries, indicating strong site fidelity. Weak but significant genetic heterogeneity was detected among nurseries based on analysis of molecular variance (0.02% variation, FST 0.00018, 95% confidence interval 0.00008-0.00028). We quantified standing genetic variation and estimated the contemporary effective population size for each nursery, and although some differences were observed, they were not statistically significant. Our results suggested that female scalloped hammerheads consistently used specific nurseries and that connectivity (via males or females straying between nurseries) facilitated the dispersal of genetic variation, which may enhance population resilience to environmental change. The genomics framework we applied is broadly applicable to conservation-based assessments of elasmobranch nurseries and essential habitats of other highly mobile species and provides a powerful tool for addressing conservation challenges.

IntroductionNursery areas for sandbar sharks (Carcharhinus plumbeus) are well-delineated along the Atlantic coast of the United States, with only a single nursery area identified in the Gulf of Mexico on the west coast of Florida.MethodsFishery-independent surveys and fishery-dependent data were used to explore the frequency and seasonality of young-of-the-year (YOY) sandbar sharks off the coast of Texas.ResultsData presented in this study demonstrate YOY are caught off the Texas coast, suggesting a potential nursery in the region. Data collected by the Texas Parks and Wildlife Department estuarine gillnet surveys and recreational shore-based shark anglers documented the presence of YOY sandbar sharks in nearshore and estuarine waters of Texas.DiscussionWhile the increase in YOY individuals were detected in the decades long fishery-independent surveys (i.e., estuarine gillnet, SEAMAP coastal and NMFS offshore longlines), fishery-dependent data collected via a shore-based recreational shark tournament documented a substantial rise in YOY sandbar sharks over a much shorter time period (10 years), supporting the usefulness of data collected by citizen scientists. For shark species, especially those with rebuilding plans, such as sandbar sharks, identifying and conserving nursery areas is important, as the decreasing amount of suitable habitat could be a limiting factor for population recovery.

We collected specimens of Axine trickyvagina Brule and Bullard n. sp. (Monogenoidea: Axinidae) from the gill lamellae of Atlantic flyingfish, Cheilopogon melanurus (Valenciennes) (Exocoetidae) in the north-central Gulf of America. Specimens of the new species were heat-killed and formalin-fixed for morphology, and others were preserved in 95% EtOH for DNA extraction and sequencing of the 28S gene and ITS1 region. The new species differs from all congeners by the combination of having a long haptor (∼40-50% of the total body length), a male copulatory organ with 10-15 spines, and a genital atrium having bilateral spinous patches each with 18-25 spines. Our study of specimens of the new species, type and voucher specimens representing 8 congeners, and all published accounts of all congeners revealed that the terminal female genitalia of Axine spp. comprises 2 ducts (a multi-chambered vagina that lacks a sclerite plus an accessory duct with a sclerotized nozzle comprising its opening) that open into a common female genital atrium. Descriptions of Axine spp. published from 1794 through 2023 failed to recognize the vaginal duct and accessory duct as distinct components and unanimously misinterpreted the accessory duct's sclerotized nozzle as a "vaginal spine." The phylogenetic analysis inferred from 28S rDNA sequences placed our sequence in a clade of other Mazocraeidea spp. and sister to a nonugen sequence ascribed to Axine japonicaPrice, 1946 (GenBank LC799038). We recovered Axinidae as sister to Heteromicrocotylidae, Heteraxinidae, and Microcotylidae. The present study is the first published description of an axinid from a flyingfish in the western Atlantic Ocean.

IntroductionMethods combining data from spatially limited, independently conducted surveys indicate a preliminary recovery for coastal shark species along the Atlantic. However, anthropogenic climate change is expected to shift distributions and alter migration timing for these highly migratory species, potentially affecting survey catchability and interpretation of abundance indices.MethodsVector autoregressive spatiotemporal (VAST) models were applied to data from six fishery-independent surveys of six coastal shark stocks to generate area-weighted indices of abundance. Area-weighted indices, trends in density over space and time, and analysis of density anomalies were used to evaluate changes in a stock’s spatial distribution across the U.S. southeast Atlantic. In addition to VAST, generalized linear mixed models were used to generate indices of abundance for each survey, which served as inputs to two previously implemented reconciliation methods in coastal shark stock assessments: dynamic factor analysis (DFA) and Bayesian hierarchical analysis (Conn).ResultsThe index standardization methods, particularly VAST and Conn, largely agreed with one another and appeared robust to spatial patterns. Only two of the six shark stocks showed increasing trends by the end of the time series, with indices for multiple species plateauing or declining. Positive trends in density and increased variability in density anomalies in the VAST models across the northern extent of the surveyed spatial domain suggests a potential northward expansion or a timing discrepancy between migration onset and sampling efforts for multiple species.DiscussionOverall, the VAST models provided evidence of spatial changes that could impact each survey’s catchability, thus complicating the interpretation of abundance trends. These findings underscore the importance of accounting for spatiotemporal dynamics in future stock assessments and fisheries management strategies.

There are significant knowledge gaps in the ecology of whale sharks Rhincodon typus beyond well-studied coastal aggregation sites. We synthesize several disparate data types, including scientific aerial and shipboard surveys, environmental impact assessments, and opportunistic citizen science records, in a species distribution model framework to characterize whale shark distribution across the northwest Atlantic Ocean (NWA), Gulf of Mexico, and the Caribbean Sea. Based on 2010 occurrence records spanning 1993-2023 from the Bay of Fundy to the North Brazil Current off the northern coast of South America, we developed a species distribution model to characterize seasonal habitat suitability for whale sharks. The model indicated that bathymetry (46.2%), sea surface temperature (21.0%), and sea surface height (16.1%) explained the most variability in habitat suitability. The model predicted high suitability in known coastal aggregation areas and continental shelf edges along the US east coast from southern Florida to Cape Hatteras year-round, expanding north to the USA-Canada border in summer and autumn. Suitability was also high in the north-central Gulf of Mexico during summer and autumn and in the Yucatan and Caribbean region throughout the year. These findings underscore a broad whale shark distribution across the NWA beyond known aggregation sites, emphasizing seasonal suitability along the US east coast and in the Gulf of Mexico. Given rapid climate-induced changes in the NWA, our findings are a critical step toward understanding climatic impacts on this charismatic species and can support marine spatial planning and conservation efforts.

We herein describe a new species of Cathariotrematinae Bullard, 2021 (Monogenoidea: Monocotylidae Taschenberg, 1879) and propose a new genus to accommodate it. Nasigulper itsgotatao n. gen., n. sp. infects the olfactory lamellae (nose) of the deepwater gulper shark, Centrophorus granulosus (Bloch and Schneider, 1801) (Squaliformes: Centrophoridae) from the north-central Gulf of Mexico outer continental shelf. The new species was assigned to Cathariotrematinae by having a 3-part attachment organ (TAO) and by lacking open loculi that symmetrically encircle a cluster of >2 loculi in the center of the haptor. The proposal of a new genus is warranted because the new species is the only known monocotylid that has a TAO comprising 3 closed loculi with 2 relatively small hamuli flanking the posteriormost loculus. The most morphologically similar cathariotrematine genus is represented by a single species (Squalotrema llewellyni Kearn and Greene, 1983) that infects the spiny dogfish, Squalus acanthias (Squaliformes: Squalidae) in the North Sea. Nasigulper itsgotatao differs from Squalotrema llewellyni by having a TAO comprising 3 closed loculi, relatively small hamuli flanking the posteriormost loculus, and a relatively short, sinous ovovitelline duct and by lacking depressions associated with the central loculus. Squalotrema llewellyni has a TAO comprising 3 supraloculi, hamuli that are equal to the length of the posteriormost loculus, a central loculus having a central depression flanked by 2 pear-shaped depressions anterolaterally, and an extensive ovovitelline duct that is sinuous sinistral to the proximal ovary. A phylogenetic analysis of all acceptable monocotylid 28S sequences recovered the new species sister to isolates of Cathariotrema selachii (MacCallum, 1916) Johnston and Tiegs, 1922 from the Gulf of Mexico (no sequence of a species of Squalotrema exists). The new genus and species are the sixth and eighth, respectively, added to Cathariotrematinae.

The age and growth of the spinner shark, Carcharhinus brevipinna, was investigated throughout its range in coastal waters of the western North Atlantic Ocean off the United States. A total of 769 vertebrae (341 males and 428 females) were collected from fishery independent and dependent sampling efforts between 1986 - 2022 and processed to estimate ages and generate growth models. Maximum observed age estimates for males and females were increased to 23.5 and 21.5 years, respectively. Sizes ranged from 482 to 1790 mm fork length (FL) for males and 410 mm to 2006 mm FL for females. All age and length data were fit to logistic, Gompertz, and von Bertalanffy models, with the three parameter von Bertalanffy model producing the best fit. Significant differences were detected between female and male model parameters with female models producing higher theoretical maximum size and lower growth constant (L infinity = 1980 mm FL, k = 0.12, to = -3.26 years) than males (L infinity = 1789 mm FL, k = 0.15, to = -2.96 years). Spatial differences in growth were also detected for females and males with spinner sharks off the east coast of the United States reaching larger asymptotic lengths but similar growth rates and size at birth relative to conspecifics in the northern Gulf of Mexico.

The expansion of the world 's merchant fleet poses a great threat to the ocean 's biodiversity. Collisions between ships and marine megafauna can have population-level consequences for vulnerable species. The Endangered whale shark ( Rhincodon typus ) shares a circumglobal distribution with this expanding fleet and tracking of movement pathways has shown that large vessel collisions pose a major threat to the species. However, it is not yet known whether they are also at risk within aggregation sites, where up to 400 individuals can gather to feed on seasonal bursts of planktonic productivity. These "constellation " sites are of significant ecological, socioeconomic and cultural value. Here, through expert elicitation, we gathered information from most known constellation sites for this species across the world ( >50 constellations and >13,000 individual whale sharks). We defined the spatial boundaries of these sites and their overlap with shipping traffic. Sites were then ranked based on relative levels of potential collision danger posed to whale sharks in the area. Our results showed that researchers and resource managers may underestimate the threat posed by large ship collisions due to a lack of direct evidence, such as injuries or witness accounts, which are available for other, sub-lethal threat categories. We found that constellations in the Arabian Sea and adjacent waters, the Gulf of Mexico, the Gulf of California, and Southeast and East Asia, had the greatest level of collision threat. We also identified 39 sites where peaks in shipping activity coincided with peak seasonal occurrences of whale sharks, sometimes across several months. Simulated collision mitigation options estimated potentially minimal impact to industry, as most whale shark core habitat areas were small. Given the threat posed by vessel collisions, a coordinated, multi-national approach to mitigation is needed within priority whale shark habitats to ensure collision protection for the species.

Hammerhead sharks (Family Sphyrnidae) comprise a monophyletic Miocene radiation of carcharhiniform sharks characterized by their laterally expanded and dorsoventrally compressed head ('cephalofoil'). The bonnethead shark (Sphyrna tiburo) is currently described as a single amphi-American hammerhead species composed of the subspecies Sphyrna tiburo tiburo in the Western Atlantic Ocean (WA) and S. tiburo vespertina in the Eastern Pacific Ocean (EP). Variation in mitochondrial DNA and cephalofoil shape suggest a species complex, with S. tiburo occurring in the U.S., Mexico, and Bahamas; S. aff. tiburo occurring from Belize to Brazil; and S. vespertina occurring in the EP. Morphometric, meristic, and genetic variation was used to resolve the bonnethead shark complex in the Western Atlantic. Twenty-three specimens (12 S. aff. tiburo from Belize and 11 S. tiburo from U.S.) were subject to sixty-one morphometric measurements and three meristic characters (counts of the number of precaudal vertebrae, lower and upper rows of functional teeth). An allometric formula was used to standardize any effect caused by differences in size of the individuals and data were analyzed with univariate and multivariate statistics. Sphyrna aff. tiburo and S. tiburo have non-overlapping vertebral counts (80-83 and 71-74 respectively) but no morphometric differences were detected. Although not captured in morphometric analysis, the cephalofoil of S. aff. tiburo has a more pointed anterior margin than S. tiburo that together with lobule shaped posterior margins gives the cephalofoil a distinctive shovel-shaped appearance. Concatenated mitochondrial sequences and 12 nuclear microsatellite markers clearly separated S. aff. tiburo and S. tiburo. We conclude that this complex comprises two species in the Western Atlantic, S. tiburo and S. alleni sp. nov., and we provide a description of the latter, which is distinguished by precaudal vertebral counts (80-83), a shovel-shaped cephalofoil with rounded posterior margins, and robust differences in mitochondrial and nuclear genetic markers. We suggest nuclear genetic and meristic examination of EP bonnetheads is needed to update the taxonomical status and redescribe S. vespertina.

Understanding spatial ecology and predicting animal movements in response to environmental changes, such as anthropogenic climate change and multidecadal variability, is critical for effective conservation strategies. Niche structuring is key to some coastal shark species and size classes coexisting in the US Atlantic and Gulf of Mexico to limit interspecific and intraspecific interaction. Data from four fishery-independent bottom longline surveys were used to evaluate the abiotic ecological niches of eight species of small and large coastal sharks. Gaussian mixture models separated length composition data into 14 size categories for ecological niche analysis. Generalized additive mixed effect models were fit and coupled with output from dynamic high-resolution ocean models to predict suitable abiotic habitats, evaluate potential shifts in distribution, and explore the impacts of large-scale climatological trends on abiotic habitats from 1994 to 2019. The abiotic niche for small coastal sharks generally tended toward warmer, high salinity, shallow bottom waters close to shore. No overarching niche was found for large coastal sharks, but appreciable ontogenetic differences were seen. Most taxa analyzed exhibited declining annual trends in higher quality habitats, particularly during fall months. The analysis provided evidence of shifts north along the Atlantic, to deeper offshore waters in the Atlantic and Gulf of Mexico, and the potential to redistribute in response to multidecadal climate variability for multiple species. The analytical framework described could aid in developing various spatiotemporal management measures, and results provide insight into the habitat characteristics of several species over broad spatiotemporal ranges and through ontogeny.

While dorsal-ventrally compressed chondrichthyans are among the most imperiled fishes in the world, there is still limited knowledge of the biology of many of these species, even in well-studied ocean basins. In the western North Atlantic Ocean, the population structure of the Atlantic angel shark (Squatina dumeril) is not fully understood; therefore, the portioning of genetic variation was assessed among individuals caught along the east coast of the United States (Atlantic) and on the northern Gulf of Mexico (Gulf) using reduced representation genomics and mitochondrial sequencing. Three distinct groups were delineated with nuclear data, the Atlantic, the eastern Gulf, and the western Gulf, along boundaries described by previous research. Mitochondrial data only resolved two groups, with the western Gulf separated from the eastern Gulf and Atlantic combined. Demographic modeling suggested that the Atlantic population separated from a single Gulf population which subsequently split into eastern and western populations. Additionally, there was evidence that adjacent populations experienced gene flow after splitting, which may explain the incongruence between results based on nuclear and mtCR data. Correlations between environmental variables and allele frequencies at 873 loci indicated potential local adaptation. Therefore, the preservation of all three groups is necessary for the conservation of long-term adaptive variation important for species persistence.

This note details the first formal report of a spinal deformation in whale sharks, Rhincodon typus. An individual whale shark with suspected kypholordoscoliosis was observed at Ewing Bank in the Gulf of Mexico during aggregation events in 2010 and 2013. Despite the significant deformity, the shark was observed feeding on fish eggs at the surface during both encounters. Based on satellite tag tracking, its movements, temperature preferences, and depth use were within the range of other whale sharks from the region.

data collected through anatomical dissection, from 48 female and 66 male tiger sharks (Galeocerdo cuvier) captured in the west-ern North Atlantic Ocean, were used to assess stage of maturity. The fork length (FL) of examined females and males ranged from 88 to 318 cm and from 84 to 349 cm, respectively. Median length at maturity (L50) was calculated by using binomial maturity data from dissections in addition to maturity assignments based on clasper condition examination of 320 males (46-280 cm FL) and pub-lished maturity data for 14 males (170- 313 cm FL) and 28 females (242-312 cm FL). Further, sex-specific median age at maturity (A50) was calculated by using direct age estimates and the aforemen-tioned binomial maturity data from the dissected specimens. Females reached L50 at 261.4 cm FL andA50 at 11.6 years. Males reached L50 at 258.9 cm FL and A50 at 9.5 years.

The age, growth, and maturity of bonnetheads, Sphyrna tiburo, inhabiting estuarine and coastal waters of the U.S. Gulf of Mexico (GOM) were investigated. Based on results of a concurrent population genetics study, two populations were examined, the eastern GOM and western GOM. Vertebrae were collected and aged from 1081 females and 811 males ranging in size 261–1060 mm and 227–898 mm fork length (FL), respectively. The von Bertalanffy growth model provided the best fit to length-at-age data. Eastern GOM von Bertalanffy parameters (length parameters in mm FL) were L∞ = 844, k = 0.23, to = -1.99, and Lo = 310 for females and L∞ = 680, k = 0.39, to = -1.44, and Lo = 294 for males. Western GOM von Bertalanffy parameters were L∞ = 1005, k = 0.20, to = -1.81, and Lo = 298 for females and L∞ = 807, k = 0.30, to = -1.44, and Lo = 285 for males. Maximum observed age was similar between populations with an overall maximum of 17.1 years for females, and 12.1 years for males. Length and age at 50

Seascape ecology has demonstrated that marine fishes are associated with multiscale habitat characteristics; however, most species distribution models focus on only a few predictors (e.g. depth, temperature), and this limits knowledge of essential fish habitat characteristics. Our objectives were to (1) determine habitat associations of offshore predatory marine fishes using a comprehensive suite of predictors, including area of nearby estuarine environments, (2) assess variable influence, and (3) model the spatial distribution of selected fishes in the families Carcharhinidae and Lutjanidae. We hypothesized that the concept of coastal outwelling would be evidenced by species associations with areas of nearby estuarine environments, and prey abundance would correlate with predator distributions. Species distribution models were developed for 2 snapper and 3 shark species in the northern Gulf of Mexico, USA. We used 34 multiscale predictors to evaluate how fish probability of presence or catch per unit effort (CPUE) were associated with oceanography, geography, substrate, area of nearby wetlands and estuaries, and prey abundance. Boosted regression trees, a machine-learning technique, modeled the most influential variables and predicted distributions. Model validation showed an overall accuracy of 79-86%, and CPUE models explained >40% of model deviance. Oceanographic variables, particularly mixed layer depth, were most influential and most frequently selected. As hypothesized, predatory fish distributions were predicted by prey abundances, and shark distributions were predicted by area of nearby coastal wetlands and estuaries. Our findings suggest that spatial models can provide novel insights into prey associations and linkages of marine species with nearby wetlands and estuaries.

Four new records of the ragged-tooth shark ( Odontaspis ferox , i.e., smalltooth sand tiger), are reported from recreational and commercial fisheries in the western North Atlantic Ocean. Two specimens of unknown sex were caught in the recreational swordfish ( Xiphias gladius ) fishery in the northern Gulf of Mexico [about 225 and 250 cm total length (TL)], a mature male was caught in the South Atlantic Bight (about 200 cm TL) by an angler targeting barrelfish ( Hyperoglyphe perciformis ), and another mature male was caught in the Sargasso Sea off Bermuda (about 275 cm TL) by a commercial fisher targeting Atlantic wreckfish ( Polyprion americanus ). All four specimens were incidentally caught on rod-and-reel and released alive. The Gulf of Mexico and South Atlantic Bight specimens reported herein contribute to the limited number of ragged-tooth shark interactions in these regions, while the observation in Bermuda is the first documented record for this locality.

The scalloped hammerhead (Sphyrna lewini) and its cryptic congener, Carolina hammerhead (S. gilberti), are sympatrically distributed in the western North Atlantic Ocean. Because the species are indistinguishable based on external morphology, little research focused on Carolina hammerheads exists. In this study, the distribution of Carolina hammerheads in waters of the United States off the east coast (U.S. Atlantic) and Gulf of Mexico (Gulf) was examined and their abundance relative to scalloped hammerheads assessed by genetically identifying 1231 individuals using diagnostic single nucleotide polymorphisms. Both species were found in the U.S. Atlantic, where 27 % of individuals were Carolina hammerheads, but only scalloped hammerheads were identified in the Gulf. In Bulls Bay, SC, a well-known hammerhead nursery, assessment of relative abundance from May to September showed scalloped hammerheads were more abundant May-June and Carolina hammerheads more abundant July-September. Results of this study suggest Carolina hammerheads have a spatially limited distribution in the western North Atlantic and highlight the importance of Bulls Bay as a nursery for the species. In addition, the results suggest Carolina hammerheads may comprise a non-trivial proportion of what is considered the U.S. Atlantic scalloped hammerhead stock and should be considered in future decisions regarding management of the hammerhead complex.

Intraspecific variability in life-history patterns is well documented in elasmobranchs, and defining regionally specific parameters is essential for proper management and sustainability of species. Studies on the reproductive biology of finetooth sharks (Carcharhinus isodon) have noted a potential disparity in periodicity within North American waters. To better define regional variability, the current study collected 1490 finetooth sharks (831 female, 659 male) from the northern Gulf of Mexico. The size-at-maturity was determined to be 995- and 961-mm fork length for females and males respectively. In males, the peak gonadosomatic index (GSI) in March and presence of semen in the seminal vesicles in April suggested spermatogenesis occurs from March to April. In females, ovulation occurred from May to June, with a peak GSI occurring in May and maximum vitellogenic follicle diameter occurring in May and June. Gestation was found to be 11–12 months, with parturition occurring in May and June and a mean brood size was 3.8±0.1 embryos. Of the 50 females examined during the ovulatory period, 32 exhibited annual and 18 exhibited biennial reproductive periodicity. The results from this study will be impactful, because regionally distinct reproductive parameters can now be considered for future assessments.

In the northern Gulf of Mexico (GOM), whale sharks (Rhincodon typus) form large aggregations at continental shelf-edge banks during summer; however, knowledge of movements once they leave aggregation sites is limited. Here we report on the seasonal occurrence of whale sharks in the northern GOM based on over 800 whale shark sightings from 1989 to 2016, as well as the movements of 42 whale sharks tagged with satellite-linked and popup satellite archival transmitting tags from 2008 to 2015. Sightings data were most numerous during summer and fall often with aggregations of individuals reported along the continental shelf break. Most sharks (66%) were tagged during this time at Ewing Bank, a known aggregation site off the coast of Louisiana. Whale shark track duration ranged from three to 366 days and all tagged individuals, which ranged from 4.5 to 12.0 m in total length, remained within the GOM. Sightings data revealed that whale sharks occurred primarily in continental shelf and shelf-edge waters (81%) whereas tag data revealed the sharks primarily inhabited continental slope and open ocean waters (91%) of the GOM. Much of their time spent in open ocean waters was associated with the edge of the Loop Current and associated mesoscale eddies. During cooler months, there was a net movement southward, corresponding with the time of reduced sighting reports. Several sharks migrated to the southwest GOM during fall and winter, suggesting this region could be important overwintering habitat and possibly represents another seasonal aggregation site. The three long-term tracked whale sharks exhibited interannual site fidelity, returning one year later to the vicinity where they were originally tagged. The increased habitat use of north central GOM waters by whale sharks as summer foraging grounds and potential interannual site fidelity to Ewing Bank demonstrate the importance of this region for this species.