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Ectoparasitic cookiecutter sharks (Chondrichthyes: Squaliformes: Dalatiidae; Isistius) share common features for jaw and teeth structure, in particular, robust lower jaws and dignathic heterodonty (upper teeth crowns are more slender and shorter than the broader and longer lower teeth crowns). The jaws and teeth are well suited for feeding by excising a nearly symmetrical oval-flesh bite plug from a variety of prey species including marine mammals, fishes, and squids. There is considerable speculation regarding cookiecutter shark bite dynamics given that natural feeding behavior has not been observed. To elucidate cookiecutter shark bite dynamics, bites were experimentally simulated for the two cookiecutter shark species; the Cookiecutter Shark, Isistius brasiliensis (Quoy JRC, Gaimard, P (1824) Zoologie (3) Imprimerie royale) and the Largetooth Cookiecutter Shark, Isistius plutodus (Garrick JAF, Springer S (1964) Isistius plutodus, a new squaloid shark from the Gulf of Mexico. Copeia 678–682), using three-dimensional printed models of jaws with teeth. Bite simulations were conducted at standardized jaw bite-gape angles and ballistic gelatin was used to approximate prey flesh, from which aspect ratio analysis of bite wound geometrics was used to determine bite wound morphometrics for each species. The simulated bite experiment also was useful for assessing factors that potentially affect cookiecutter shark total length estimates when based on natural bite geometrics. In addition, the mechanics of producing experimental bites provide new insights related to the necessity for cookiecutter sharks to rotate their body to create nearly symmetrical oval bite wounds.

The function of pocket shark pectoral pockets has puzzled scientists over decades. Here, we show that the pockets of the American Pocket Shark (Mollisquama mississippiensis) contain a brightly fluorescent stratified cubic epithelium enclosed in a pigmented sheath and in close contact with the basal cartilage of the pectoral fins; cells of this epithelium display a centripetal gradient in size and a centrifuge gradient in fluorescence. These results strongly support the idea that pocket shark’s pockets are exocrine holocrine glands capable of discharging a bioluminescent fluid, potentially upon a given movement of the pectoral fin. Such capability has been reported in many other marine organisms and is typically used as a close-range defensive trick. In situ observations would be required to confirm this hypothesis.

A new species of kitefin shark (Squaliformes; Dalatiidae) is described from the Gulf of Mexico (Western North Atlantic Ocean) based on five diagnostic features not seen on the only other known Mollisquama specimen, the holotype of Mollisquama parini Dolganov which was captured in the Eastern South Pacific Ocean. The new species, Mollisquama mississippiensis sp. nov., is distinguished from its congener by a putative pit organ located ventrally just posterior of the lower jaw margin center, photophores irregularly distributed along many areas of the body, 16 distinct ventral-abdominal photophore aggregations, and two differences associated with the dentition. Other potential distinguishing features are 10 fewer vertebrae than Mollisquama parini and six morphometric proportional differences that exceeded +/- 20% from the holotype.

Dalatiid sharks are members of a family of predominantly small, midwater meso‐ and bathypelagic chondrichthyans. The family is notable for both its number of monotypic genera and high morphological disparity. Three of the seven dalatiid genera are known only from holotype specimens (Mollisquama parini) or from only a handful of specimens (Euprotomicroides zantedeschia, Heteroscymnoides marleyi), with the only detailed anatomical work consistent across all taxa being studies of dentition. Here, we present detailed anatomical description of the second‐ever specimen of Mollisquama (Mollisquama sp.) covering chondrocranial, jaw, dental, and muscular anatomy, derived from a phase‐contrast synchrotron microtomographic scan. Mollisquama sp. is unique among dalatiids in possessing a deep carinal process, extending ventrally from the bar between the subethmoid region and basal angle in squaloid sharks, containing a large fenestra infiltrated by the suborbitalis muscle. Mollisquama sp. also exhibits additional possibly diagnostic features, including a planar configuration of the labial cartilages and the absence of labial folds; a pad‐like orbital process on the palatoquadrate; and the origination of the suborbitalis muscle solely on the carina, rather than the intraorbital wall. Character optimization of anatomical data onto a phylogeny of dalatiid sharks suggests Mollisquama sp. to be among the most specialized in the family, expanding the existing dalatiid morphospace. However, the functional significance of such transformations remains unclear. Synchrotron‐derived data, which do not require chemical pretreatment of specimens, may elucidate soft‐tissue functional correlates in future studies of undersampled taxa, such as dalatiids.

Few accounts describe predator-prey interactions between common bottlenose dolphins (Tursiops truncatus Montagu 1821) and marine catfish (Ariopsis felis Linnaeus 1766, Bagre marinus Mitchill 1815). Over the course of 50,167 sightings of bottlenose dolphin groups in Mississippi Sound and along the Florida coast of the Gulf of Mexico, severed catfish heads were found floating and exhibiting movements at the surface in close proximity to 13 dolphin groups that demonstrated feeding behavior. These observations prompted a multi-disciplinary approach to study the predator-prey relationship between bottlenose dolphins and marine catfish. A review was conducted of bottlenose dolphin visual survey data and dorsal fin photographs from sightings where severed catfish heads were observed. Recovered severed catfish heads were preserved and studied, whole marine catfish were collected and examined, and stranding network pathology reports were reviewed for references to injuries related to fish spines. Photographic identification analysis confirms eight dolphins associated with severed catfish heads were present in three such sightings across an approximately 350 km expanse of coast between the Mississippi Sound and Saint Joseph Bay, FL. An examination of the severed catfish heads indicated interaction with dolphins, and fresh-caught whole hardhead catfish (A. felis) were examined to estimate the presumed total length of the catfish before decapitation. Thirty-eight instances of significant trauma or death in dolphins attributed to ingesting whole marine catfish were documented in stranding records collected from the southeastern United States of America. Bottlenose dolphins typically adhere to a ram-feeding strategy for prey capture followed by whole prey ingestion; however, marine catfish skull morphology may pose a consumption hazard due to rigid spines that can puncture and migrate through soft tissue, prompting a prey handling technique for certain dolphins, facilitating consumption of the posterior portion of the fish without the head.

During a pelagic longline pilot study conducted by the National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Southeast Fisheries Science Center, Mississippi Laboratories along the US Atlantic Ocean coast (NOAA Ship OREGON II OT-06-02-269), a Caretta caretta (Loggerhead Sea Turtle) was captured with longline gear equipped with time-temperature-depth recorders attached in proximity to hooks. Time-temperature-depth data documented changes in hook depth and water temperature, and reflected behavior of the Loggerhead Sea Turtle (rates of descent and ascent, time at depth, time near surface). Sea turtle mortality mitigation recommendations for pelagic longline gear proved effective for this Loggerhead Sea Turtle capture since there were successive ascents to surface, and the viability status was good after landing.

Epinephelus morio (Red Grouper) is an important component of com- mercial fi sheries for the United States and Mexico. Fishery-independent long-line surveys that utilized standardized sampling designs were conducted along the west Florida shelf, Florida and Campeche Bank, Mexico (2001-2002). Detecting true dif- ferences in abundance and sizes are diffi cult, but by using standard collection and aging methodologies, the level of bias was kept at a minimum. Relative abundance was higher in the Campeche Bank compared to the west Florida shelf (1.74 and 0.63 Red Grouper/100 hook hr, respectively). Fish from the Campeche Bank were also signifi cantly smaller at length and weight. Differences in length, weight, and relative abundance of Red Grouper may be because of historical fi shing pressure and man- agement regulations, or the available carrying capacity of each area for Red Grouper. These differences have a substantial impact on how an overfi shed population can recover and be sustained.

From 1995 through 2006, 2577 bottom longline sets were conducted in the western North Atlantic Ocean from ~36° N, 75° W to 26° N, 97° W, an area that encompasses both the coastal waters off the southeastern USA (Atlantic) and the northern Gulf of Mexico (Gulf). Over the course of the study, 335 young-of-the-year (YOY) and 219 juvenile tiger sharks Galeocerdo cuvier were cap- tured. In the Gulf, YOY catch per unit effort (CPUE) was highest from ~88 to 83° W. In the Atlantic, the area of highest YOY CPUE occurred from 31 to 33° N. Distribution of juvenile tiger sharks was more uniform than observed for YOY throughout the range of the study. Annual survival rates of YOY and Age 1+ tiger sharks were estimated to be 51 and 62% in the Gulf and 39 and 27% in the Atlantic. Total instantaneous mortality rates of YOY and Age 1+ tiger sharks were, respectively, estimated to be 0.67 and 0.47 in the Gulf and 0.93 and 1.32 in the Atlantic. In the Atlantic, age-specific natural mortality (M) estimates ranged from 0.12 to 0.50 and from 0.08 to 0.36 for YOY and juvenile tigers sharks, respectively. Estimates of age-specific M were more variable in the Gulf, with values ranging from 0.11 to 0.98 for YOY and from 0.08 to 0.57 for juveniles. In the absence of nursery areas, the pro- duction of numerous fast-growing offspring presumably helps the species survive in the face of high total mortality.

For fisheries research the lengths and weights of fishes are important data elements used to characterize biological dynamics; however, in order to collect accurate lengths and weights there can be stress and mortality issues due to handling methods. In particular, during coastal and oceanic longline projects, collecting accurate biological data from large animals is often problematic due to associated landing and handling difficulties. To improve the accuracy of biological data collected from large specimens and decrease survey-induced stress and mortalities during longline surveys, a portable landing sling was designed for use with shipboard hydraulic cranes. The landing sling enables researchers to improve biological data quality through increased opportunities to collect accurate lengths and weights, take detailed photographs, and conduct non-invasive biological sampling with minimal physical damage to large fishes captured. Thus, using a landing sling allows researchers to collect essential biological data while being responsibly conservative.

The description of the pocket shark genus Mollisquama (M. parini Dolganov, 1984) is based on a single known specimen collected from the Nazca Ridge of the southeast Pacific Ocean. A second Mollisquama specimen has been captured in the central Gulf of Mexico establishing a considerable range extension and a parturition locality because the specimen has a healed vitelline scar. Both the holotype of M. parini and the Gulf of Mexico specimen possess the remarkable pocket gland with its large slit-like external opening located just above the pectoral fin. Features found on the Gulf of Mexico specimen that were not noted in the description of M. parini include a series of ventral abdominal photophore agglomerations and a modified dermal denticle surrounded by a radiating arrangement of denticles just posterior to the mouth. Based on a morphometric and meristic comparison of the Gulf of Mexico specimen with information in the description of M. parini, the Gulf of Mexico specimen is identified as Mollisquama sp. due to differences in tooth morphology and vertebral counts. Phylogenetic analysis of NADH2 gene sequences places Mollisquama sister to Dalatias plus Isistius within the family Dalatiidae.

Identification of the spatial scale at which marine communities are organized is critical to proper management, yet this is particularly difficult to determine for highly migratory species like sharks. We used shark catch data collected during 2006–09 from fishery-independent bottom-longline surveys, as well as biotic and abiotic explanatory data to identify the factors that affect the distribution of coastal sharks at 2 spatial scales in the northern Gulf of Mexico. Centered principal component analyses (PCAs) were used to visualize the patterns that characterize shark distributions at small (Alabama and Mississippi coast) and large (northern Gulf of Mexico) spatial scales. Environmental data on temperature, salinity, dissolved oxygen (DO), depth, fish and crustacean biomass, and chlorophyll-a (chl-a) concentration were analyzed with normed PCAs at both spatial scales. The relationships between values of shark catch per unit of effort (CPUE) and environmental factors were then analyzed at each scale with co-inertia analysis (COIA). Results from COIA indicated that the degree of agreement between the structure of the environmental and shark data sets was relatively higher at the small spatial scale than at the large one. CPUE of Blacktip Shark (Carcharhinus limbatus) was related positively with crustacean biomass at both spatial scales. Similarly, CPUE of Atlantic Sharpnose Shark (Rhizoprionodon terraenovae) was related positively with chl-a concentration and negatively with DO at both spatial scales. Conversely, distribution of Blacknose Shark (C. acronotus) displayed a contrasting relationship with depth at the 2 scales considered. Our results indicate that the factors influencing the distribution of sharks in the northern Gulf of Mexico are species specific but generally transcend the spatial boundaries used in our analyses.

Eggs and larvae of Huffmanela oleumimica n. sp. infect red snapper, Lutjanus campechanus (Poey, 1860), were collected from the Texas-Louisiana Shelf (28°16'36.58″N, 93°03'51.08″W) and are herein described using light and scanning electron microscopy. Eggs in skin comprised fields (1-5 × 1-12 mm; 250 eggs/mm(2)) of variously oriented eggs deposited in dense patches or in scribble-like tracks. Eggs had clear (larvae indistinct, principally vitelline material), amber (developing larvae present) or brown (fully developed larvae present; little, or no, vitelline material) shells and measured 46-54 μm (x = 50; SD ± 1.6; n = 213) long, 23-33 (27 ± 1.4; 213) wide, 2-3 (3 ± 0.5; 213) in eggshell thickness, 18-25 (21 ± 1.1; 213) in vitelline mass width, and 36-42 (39 ± 1.1; 213) in vitelline mass length with protruding polar plugs 5-9 (7 ± 0.6; 213) long and 5-8 (6 ± 0.5; 213) wide. Fully developed larvae were 160-201 (176 ± 7.9) long and 7-8 (7 ± 0.5) wide, had transverse cuticular ridges, and were emerging from some eggs within and beneath epidermis. The new species differs from its congeners by having eggs65 μm in total length and that have a brown eggshell when fully developed, an envelope throughout development, and irregularly-dispersed eggshell spines plus a larva110 μm long with transverse cuticular ridges. The eggs lack a spindle-shaped envelope, polar filaments, and eggshell ridges. This is the first report of a species of Huffmanela from a snapper (Lutjanidae) or from the Gulf of Mexico. A table of egg and larval characteristics, hosts, and localities for Huffmanela spp. is provided.

C, 5.7 mg/l and 36.5, respec-tively. An incision was made through the abdominal muscu-lature and the gastrointestinal and reproductive organs were excised. Fresh material was used for all examinations and pho-tographs. The specimen was frozen after inspection, and later deposited in the museum at the University of Southern Mis-sissippi, Gulf Coast Research Laboratory (accession number GCRL 36376). Anatomical terms used in descriptions follow Dean (1906), Wourms (1977) and Jones et al. (2005).

The description of the pocket shark genus Mollisquama (M. parini Dolganov, 1984) is based on a single known specimen collected from the Nazca Ridge of the southeast Pacific Ocean. A second Mollisquama specimen has been captured in the central Gulf of Mexico establishing a considerable range extension and a parturition locality because the specimen has a healed vitelline scar. Both the holotype of M. parini and the Gulf of Mexico specimen possess the remarkable pocket gland with its large slit-like external opening located just above the pectoral fin. Features found on the Gulf of Mexico specimen that were not noted in the description of M. parini include a series of ventral abdominal photophore agglomerations and a modified dermal denticle surrounded by a radiating arrangement of denticles just posterior to the mouth. Based on a morphometric and meristic comparison of the Gulf of Mexico specimen with information in the description of M. parini, the Gulf of Mexico specimen is identified as Mollisquama sp. due to differences in tooth morphology and vertebral counts. Phylogenetic analysis of NADH2 gene sequences places Mollisquama sister to Dalatias plus Isistius within the family Dalatiidae.

Since 1991, the National Marine Fisheries Service (NMFS) has used a video camera/trap system to assess the relative abundance of reeffishes in the Gulf of Mexico occurring on natural hard-bottom substrata at depths between 9 m and 110 m. The relative index of reef-fish abundance resulting from these annual Gulf-wide surveys is based on counts of fish recorded during a 1 h set of a video camera on the bottom. During the 1993 reef-fish survey, a total of 115 reef sites were sampled with a video camera and fisheries acoustic system. Video data were used to identify fish species distributed above the bottom. OV-bottom fish included snappers (Lutjanidae), groupers (Serranidae), and amberjacks (Seriolaspp.), species of interest to commercial and recreational fisheries. Correlation between total oV-bottom taxa abundance and volume backscatter was low (r=0.41, n=115). The low correlation may be caused by diVerences in the area sampled by the video camera and acoustic systems at each site. The low correlation limits the use of acoustic data as an auxiliary variable in a combined video-acoustic estimator. ? 1996 International Council for the Exploration of the Sea