Red Snapper Lutjanus campechanus represent one of the more economically important fisheries in the northern Gulf of Mexico; as such, Red Snapper abundance has decreased dramatically in the past two decades. The use of artificial reefs could aid in the rehabilitation of Red Snapper stocks by providing refuge for juveniles and a place of foraging and recruitment. A study was initiated to determine the effectiveness of different artificial reef distribution patterns in attracting and sustaining juvenile Red Snapper in the northern Gulf of Mexico. Fish traps (0.97 m long; 0.64 m high; funnel mouth size = 175 × 115 mm) were used to collect Red Snapper (<406 mm TL) that were associated with pyramid-shaped artificial reef structures (3.7-m triangular base; 2.4-m height; 3.2 metric tons) to evaluate two reef distribution designs: (1) five closely spaced pyramid units (“clumped” pattern) and (2) five closely spaced pyramids plus two sets of two pyramids at 30.5, 61.0, or 91.5 m from the five pyramids (“outlier” pattern). In 26 sampling trips, 927 Red Snapper were captured. Catch per unit effort (number of fish/trap soak-hour) did not differ significantly among artificial reef patterns (P = 0.396). Red Snapper TLs differed significantly among patterns (P = 0.005), with the largest mean TL (235 mm; SE = 5.14) occurring at the outlier pattern with 61.0-m spacing. Results from this study indicate that reef spacing and horizontal extension are important factors to consider when designing an artificial reef program, especially those that target juvenile Red Snapper.

Alewife Alosa pseudoharengus is an anadromous clupeid fish of long-standing ecological and socioeconomic importance along the Atlantic coast of North America. Since the 1970s, Alewife populations have been declining throughout the species' range. A number of hypotheses have been proposed to explain the decline, but a lack of basic information on population demographics inhibits hypothesis testing. In this study, we evaluated the use of morphometric analysis to discriminate among spawning stocks of Alewives collected from 24 sites in Maine and one site in Massachusetts. We first identified 10 morphometric measurements that were not influenced by the freezing—thawing process, and then used principal component and discriminant function analyses to develop stock-structure classification models from these 10 measurements. Classification models were able to discriminate Alewives to be from Maine or the single Massachusetts site 100% of the time. In addition, classification models correctly classified pooled sampling sites from the extreme western and eastern parts of Maine with 64% accuracy. Morphometric analysis may therefore provide an easily accessible, comparatively fast, and inexpensive method to discriminate marine-captured Alewives spawned in areas separated by major biogeographic regions, large geographic distances (100s of kilometers), or both, and thus help inform questions about stock composition at these spatial scales for assessment surveys and bycatch events.

Despite the ecological and economic importance of rockfish fisheries in Alaska waters, little information is available concerning the reproductive biology of the majority of federally managed rockfish species in the Gulf of Alaska. Pacific Ocean Perch Sebastes alutus are the most abundant and commercially important rockfish in this region. This study examines the reproductive biology of Pacific Ocean Perch within the Gulf of Alaska, utilizing histological techniques to microscopically examine ovarian tissue. Pacific Ocean Perch samples were obtained throughout the year during National Marine Fisheries Service and Alaska Department of Fish and Game scientific surveys, as well as scientific charters. Ovaries of Pacific Ocean Perch began to ripen during the month of August with yolk increasing until February. Embryos appeared within the ovaries during February and continued to grow and develop until parturition in May. Results from this study indicate the fork length at 50% maturity is 33.4 cm and the age at 50% maturity is 8.4 years. Both of these values are smaller than those currently utilized in the stock assessment of Gulf of Alaska Pacific Ocean Perch. Results from this study will improve the stock assessment of this species by providing more accurate estimates of reproductive parameters and reducing the uncertainty in estimates of length and age at maturity.

Bull Sharks Carcharhinus leucas in the Indian River Lagoon, Florida, have been documented to frequently occur in humanaltered habitats, including dredged creeks and channels, boat marinas, and power plant outfalls. The purpose of this study was to examine the short-term movements of age-0 and juvenile Bull Sharks to quantify the extent to which those movements occur in altered habitats. A total of 16 short-term active acoustic tracks (2–26 h) were carried out with 9 individuals, and a 10th individual was fitted with a long-term coded transmitter for passive monitoring by fixed listening stations. Movement and activity space statistics indicated high levels of area reuse over the span of tracking (hours to days). All but one shark used altered habitat at some point during tracking, such that 51% of all tracking positions occurred in some type of altered habitat. Of the sharks that used altered habitat, the mean ( ± 1 SD) percent of positions within altered habitat was 66 ( ± 40) %. Furthermore, tracks for 3 individuals indicated selection for altered habitats. The single passively monitored Bull Shark was detected in power plant outfalls almost daily over a 5-month period, providing the first indication of longer-term fidelity to thermal effluents. Use of one dredged creek was influenced by local salinity, the tracked sharks dispersing from the altered habitat when salinity declined. The affinity of young Bull Sharks to altered habitats in this system could help explain their reported accumulation of a variety of harmful contaminants, which could negatively affect their health and survival.

Contemporary studies have shown that spawning stock biomass can be a poor estimator of total egg production, with the inclusion of fecundity tending to improve stock—recruit relationships. Since many U.S. fisheries now use spawning potential ratio (SPR) to define overfishing, an understanding of fecundity variation is especially valuable. We studied a commercially important, protogynous sparid, the Red Porgy Pagrus pagrus, off the southeast U.S. coast from 2007 to 2010 to estimate annual fecundity (f_a ) as a function of batch fecundity (f_b ) and batch number (n_b ) and to investigate size-based and temporal variation. In total, 1,355 Red Porgy (241–478 mm TL) were collected; subsets of individuals were selected for estimating maturity, n_b , and fb. Throughout the spawning season, the proportion of females that were capable of spawning increased to 100% on several dates and was generally higher among smaller females than current maturity information would predict. The proportion of females that were actually spawning was also as high as 100% on several dates, suggesting periods of daily spawning. Batch fecundity was positively related to TL, and the relationship varied significantly between years and among months within years. Spawning fraction (and thus n_b ) was also size dependent, with relationships varying between years and dependent upon the reproductive indicator used in calculation (i.e., spawning capability, postovulatory follicle presence, or hydrated oocyte presence). Annual fecundity estimates incorporating size-dependent n_b differed from estimates assuming size-independent n_b and varied between years. Through its effect on fa, the size dependence of n_b ultimately affected perceptions of how fishing mortality rate influenced the SPR. Our findings show the importance of accounting for size-dependent variation in n_b when calculating fa in indeterminate-spawning species and illustrate the potential implications for stock—recruit relationships and stock exploitation status.

Offshore oil platforms function as artificial reefs, but little is known about the food webs that fuel platform-dwelling biota. Here, we use carbon and nitrogen isotopes in tissues of biota from two offshore oil platforms to estimate the importance of phytoplankton and platform-associated macroalgae and epiphytic microalgae to the diets of platform-dwelling consumers. Although the consumption of macroalgae was indicated for small, mobile consumers including crabs, amphipods, and harpacticoid copepods, both a Bayesian mixing model and temporal changes in isotope composition identified phytoplankton as the most important basal resource for these consumers. Sessile suspension-feeding barnacles and oysters consumed phytoplankton and epiphytes, and probably redirected large amounts of pelagic production to other consumers. Secondary consumers including syllid polychaetes and the blennies, Molly Miller Scartella cristata and Tessellated Blenny Hypsoblennius invemar, exhibited a distinct contribution from epiphytes although large ranges in all potential basal resources were observed. Elemental and isotope analysis of the gut contents of individuals indicated that the nektonic Gray Triggerfish Balistes capriscus was omnivorous, directly consuming reef-derived macroalgae and epiphytes as well as animal tissue. Although we found that reef-derived resources entered benthic and nektonic food webs surrounding platforms, phytoplankton was the dominant basal resource fueling platform-dwelling communities at the time of our study, and no consumer studied specialized on a diet of red macroalgae. If these findings are generally representative, platform-derived benthic algae would not be integral to food-web function on artificial reefs, and reef function should be similar in areas both favorable to and unfavorable to in situ algal growth.

The Yellow River estuary ecosystem is an important spawning ground for many species found in the Bohai Sea and Yellow Sea and contributes substantially to the fishery resource structure and biological reproduction in the northern China Sea. Based on long-term ecosystem surveys in the Yellow River estuary during the main spawning period (May) of most fishery species from 1959 to 2011, the responses of the ecosystem, including regime shifts in species composition, biomass, diversity, and other related factors, were analyzed in this study. Since the 1980s, the dominant large-size species of high economic value (e.g., Largehead Hairtail Trichiurus lepturus) have been replaced by short-lived, low-trophic-level, planktivorous pelagic species (e.g., Scaly Hairfin Anchovy Setipinna taty and Japanese Anchovy Engraulis japonicus). Currently, traditional commercially targeted fishes, such as the Largehead Hairtail, Red Seabream Pagrus major, and Pacific Herring Clupea pallasii, are locally extinct. There has been a rapid shift of dominant species from highly valued, high-trophic-level, large-sized demersal species with complicated age structures to low-value, low-trophic-level, small-sized pelagic species with simple age structures; this shift has resulted in major changes to the ecological cycle and restoration of fishery resources. The fish catch declined from 421.66 kg/h in 1959 to 0.25 kg/h in 2008 and then increased to 3.62 kg/h in 2011. Diversity and evenness indices showed a continuously increasing trend during 1959–2011. The Yellow River estuary may be significantly compromised by overfishing, climate change, dam construction, and pollution, resulting in the decline of traditional fishing industries and reduced biodiversity in this ecosystem.

Spotted Seatrout Cynoscion nebulosus is the most highly sought after recreational species along the U.S. Gulf coast. However, movement information for this economically and ecologically important species is currently limited to data from mark—recapture studies. We used remote acoustic telemetry, a high-resolution, fisheries-independent technique, to examine the residency of adult Spotted Seatrout (n = 172) in a Louisiana estuary, Calcasieu Lake (∼300 km²). An estuarine-wide array of 60 receivers was deployed for a 2.5-year period (May 2007–October 2009) to detect and quantify how long fish were present in the estuary and determine the proportion of fish that emigrated from the system. We then determined how these metrics (detection period and emigration) were related to fish size, sex, and season of release. Emigration was highly seasonal and occurred exclusively during late spring and summer when water temperatures exceeded 24°C. Surprisingly, male Spotted Seatrout, regardless of their size, were more likely than females to “permanently” emigrate from the estuary (i.e., not return within the 1-year battery life of transmitters) as evidenced by their shorter mean detection periods (males = 134 d, females = 177 d) and higher incidence of emigration (29–42% of males, but only 14–16% of females emigrated). Assessment and management strategies for this species may be improved by explicitly considering this behavioral difference between sexes. Namely, conducting stock assessments at a finer spatial scale (i.e., estuarine-specific versus state-wide) appears warranted given the high estuarine fidelity of females (∼85%), which exacerbates their potential for localized depletions due to anthropogenic stressors (e.g., fishing pressure, habitat alteration, or pollution).

Large sharks are top predators in most coastal and marine ecosystems throughout the world, and evidence of their reduced prominence in marine ecosystems has been a serious concern for fisheries and ecosystem management. Unfortunately, quantitative data to document the extent, timing, and consequences of changes in shark populations are scarce, thwarting examination of long-term (decadal, century) trends, and reconstructions based on incomplete data sets have been the subject of debate. Absence of quantitative descriptors of past ecological conditions is a generic problem facing many fields of science but is particularly troublesome for fisheries scientists who must develop specific targets for restoration. We were able to use quantitative measurements of shark sizes collected annually and independently of any scientific survey by thousands of recreational fishermen over the last century to document decreases in the size of large sharks from the northern Gulf of Mexico. Based on records from fishing rodeos in three U.S. coastal states, the size (weight or length) of large sharks captured by fishermen decreased by 50–70% during the 20 years after the 1980s. The pattern is largely driven by reductions in the occurrence and sizes of Tiger Sharks Galeocerdo cuvier and Bull Sharks Carcharhinus leucas and to a lesser extent Hammerheads Sphyrna spp. This decrease occurred despite increasing fishing effort and advances in technology, but it is coincident with the capitalization of the U.S. commercial shark long-line fishery in the GOM.

We examined the effects of wind-driven sediment resuspension on the stomach fullness, prey composition, and caloric intake of Bay Anchovy Anchoa mitchilli, a particulate planktivore, and age-0 Atlantic Croaker Micropogonias undulatus, a benthic omnivore, in Mobile Bay, Alabama. Mobile Bay is a shallow estuary in the northern Gulf of Mexico with substrates ranging from silt to small sand. High-wind events were associated with cold fronts and were characterized by wind velocities ≥4.0 m/s. Bay Anchovy stomachs were less full during such events and gut contents contained greater contributions by low-calorie items. Atlantic Croaker stomach fullness did not differ significantly with wind speed. However, prey composition during high-wind events shifted toward high-calorie items. These scenarios imply that high-wind events in Mobile Bay could have an adverse effect on energy uptake by resident Bay Anchovy but may benefit energy uptake by Atlantic Croaker.

Seagrass habitats have long been known to serve as nursery habitats for juvenile fish by providing refuges from predation and areas of high forage abundance. However, comparatively less is known about other factors structuring fish communities that make extensive use of seagrass as nursery habitat. We examined both physical and biological factors that may structure the juvenile seagrass-associated fish communities across a synoptic-scale multiyear study in lower Chesapeake Bay. Across 3 years of sampling, we collected 21,153 fish from 31 species. Silver Perch Bairdiella chrysoura made up over 86% of all individuals collected. Nine additional species made up at least 1% of the fish community in the bay but were at very different abundances than historical estimates of the fish community from the early 1980s. Eight species, including Silver Perch, showed a relationship with measured gradients of temperature or salinity and Spot Leiostomus xanthurus showed a negative relationship with the presence of macroalgae. Climate change, particularly increased precipitation and runoff from frequent and intense events, has the potential to alter fish—habitat relationships in seagrass beds and other habitats and may have already altered the fish community composition. Comparisons of fish species to historical data from the 1970s, our data, and recent contemporary data in the late 2000s suggests this has occurred.

Reproductive and age data were collected for Blacktip Sharks Carcharhinus limbatus in the Gulf of Mexico from fishery-dependent and -independent sources from 2006 to 2011 for stock assessment. A total of 757 Blacktip Sharks were sampled for reproductive analysis (399 females, 358 males), of which 741 were aged. Additional length and age data from a previous age and growth study on Blacktip Sharks in the Gulf of Mexico (207 females, 161 males) were incorporated into the size- and age-at-maturity analyses. The results indicated that Blacktip Sharks in the Gulf of Mexico have a synchronous, seasonal reproductive cycle and that females exhibit a biennial ovarian cycle. Male and female mating and parturition peaked from March to May. Length at 50% maturity was estimated to be 105.8 and 119.2 cm FL for males and females, respectively, while age at 50% maturity was calculated as 4.8 and 6.3 years. Near-term pups averaged 38 cm FL, and gestation was approximately 12 months. Litter size was 4.5 pups per female, and fecundity was found to increase with both maternal size and age. Maternal body size—but not age—had a positive influence on offspring fitness. This represents the first comprehensive reproductive study of Blacktip Sharks in the Gulf of Mexico.

The reproductive biology of the Atlantic Sharpnose Shark Rhizoprionodon terraenovae in the Gulf of Mexico was investigated by examining 1,306 specimens (693 females, 613 males) collected from the Florida Keys to waters off Brownsville, Texas. The results of this study confirm the annual reproductive cycle established for this species; however, there was a significant amount of variability within the cycle. Ovulatory and postovulatory females were present from March to October, indicating that mating and ovulation were occurring over a more protracted period than previously described (e.g., May to July). The occurrence of postpartum females from April to September, the varying sizes of the embryos across several months, and the occurrence of mature spermatozoa in the testes of adults from March to November also corroborate the evidence of reproductive plasticity in this species. This observed variability in the reproductive cycle indicates that the Gulf of Mexico Atlantic Sharpnose Shark population is not completely synchronous in regards to mating, ovulation, and parturition, as a portion of the population is demonstrating reproductive asynchrony. Although the cause of this asynchrony remains unclear, it may be related to the environmental conditions of the Gulf of Mexico, which could provide water temperatures that are optimal for the reproduction of this species through much of the year (i.e., March to October), resulting in a protracted reproductive cycle. Given the results of the current study, the reproductive cycles of other carcharhinid species in this region should be examined in more detail to determine whether there is asynchrony in them as well, as this phenomenon could impact future management strategies.

Within the northern Gulf of Mexico, the Cuban Dogfish Squalus cubensis is the most frequently encountered squalid in continental shelf and slope waters. Despite the relatively high abundance of Cuban Dogfish in the region, there is a dearth of information regarding even the most basic aspects of the species' biology. Furthermore, what has been reported is conflicting and of questionable utility. From 2005 to 2012, 139 male and 252 female Cuban Dogfish were collected opportunistically. The analyses indicated that male Cuban Dogfish reach 50% maturity at 379 mm stretch total length (STL) and are capable of reproducing throughout the year. Females reach 50% maturity at 466 mm STL and 50% maternity at 478 mm STL. Brood size ranges from one to four, and vitellogenesis and gestation are concurrent. Although samples were not collected during all months of the year, the presence of ova in the blastodisc stage of development during the summer and fall, coupled with the relatively high variability of embryo size within fall months, suggest that Cuban Dogfish reproduce asynchronously.

The Cownose Ray Rhinoptera bonasus is an abundant species in the western Atlantic Ocean, including the Gulf of Mexico, but its reproductive biology is not completely known because of the difficulty of obtaining year-roundsamples in large portions of its range where the species is migratory. To address this knowledge gap, Cownose Rays were studied in a subtropical estuarine system where rays are available year-round. Size at maturity and reproductive cyclicity were assessed using 140 females and 151 males. For females, the size at 50% maturity was 701 mm disk width (DW) based on ovary length and weight, maximum follicle diameter, and mating wounds and scars; the size at 100% maturity was 712 mm DW. For males, the size at 50% maturity was 681 mm DW based on clasper morphology, testis length and weight, and epididymis width; the size at 100% maturity was 712 mm DW. Overall testis size (length and weight) and mean testis lobe diameter peaked up to 2 months prior to ovary size and maximum follicle diameter, indicating that males were preparing to inseminate females during the entire parturition and mating period.Mating behaviors and fresh mating wounds were observed mostly between April and June. Ovulation peaked in May, and parturition occurred primarily in March and April after an 11–12 month, single-embryo gestation period, suggesting that females are synchronous in Charlotte Harbor. Size at birth was 202–383 mm DW. Concurrent vitellogenesis and gestation indicated a clearly defined annual reproductive cycle that may be completed within the estuary. Understanding reproductive life history in wide-ranging species such as the Cownose Ray is useful in the short term for making sound management decisions and for future comparison as the effects of global climate change are realized.

An intersexual Blacktip Shark Carcharhinus limbatus with a testis, immature female reproductive tracts (embedded), and claspers was caught in the Gulf of Mexico. Histology of the single gonad revealed that all stages of spermatogenesis were occurring; however, the absence of ovaries and a male duct system suggests that neither sex would have been functional in this individual. Intersexuality has been reported in 17 families and 36 species of elasmobranchs. The degree to which the different sexes are present in a given individual is often difficult to categorize by normal hermaphroditic standards, as this is typically an anomalous presentation in elasmobranchs. Therefore, this report provides three categories for classification (basic, incomplete, and complete intersexuality) to standardize terminology and allow for more precise comparisons to be made among elasmobranch examples. Basic intersexuals have gonadal tissue of only one sex and a combination of other male and female characters with neither or only one sex being complete. Incomplete intersexuals have gonadal tissue of both sexes and a combination of other male and female characters; however, neither or only one sex is complete. Complete intersexuals have claspers as well as gonadal tissue and tracts for both sexes. The majority of the reported intersexual elasmobranchs, including the shark described here, are basic intersexuals.

An understanding of basic reproductive biology is essential for successful species-specific management of elasmobranch fishes (sharks, skates, and rays). Such information is often gained through gross dissection or other lethal techniques, which are not appropriate for threatened and endangered species. Previous work on other vertebrates suggested that sex steroid hormones can be extracted from muscle tissues to identify reproductive status. Collecting for muscle biopsy is quick and minimally invasive and can be done without removing an animal from the water. Thus, the objective of the current study was to determine the efficacy of using muscle steroid hormones to assess the reproductive biology of elasmobranch fishes. The results suggest that concentrations of muscle progesterone, testosterone, and estradiol can be successfully quantified to study reproduction by radioimmunoassay. Additionally, there were significant correlations between the plasma and muscle estradiol concentrations in Spiny Dogfish Squalus acanthias and the progesterone, testosterone, and estradiol concentrations in Atlantic Sharpnose Sharks Rhizoprionodon terraenovae. The present investigation thus demonstrates that skeletal muscle is a nonlethally harvestable tissue that is well suited for studying the reproductive biology of elasmobranchs.

The number of Sandbar Sharks Carcharhinus plumbeus in the western North Atlantic Ocean has experienced a drastic decline since the early 1980s, reaching a minimum during the early 1990s. Catch rates in the early 1990s were a mere 25% of those during the 1980s. According to several fishery-independent surveys, the low point in Sandbar Shark abundance followed a period of high exploitation. Growth models fit to age-length data collected from 1980 to 1983 and from 2001 to 2004 were compared to investigate potential changes in parameter estimates that might reveal compensatory responses in the Sandbar Shark population. Statistical differences were found between themodel parameters for the two time periods, but the differences in growth rates were minimal. The parameters from the three-parameter von Bertalanffy growth model for female sharks during the 1980–1983 and 2000–2004 time periods were as follows: L_∞ = 188.4 and 178.3 cm FL; k = 0.084 and 0.106; and t₀ = -4.097 and -3.41. For males the growth parameters were as follows: L_∞ = 164.63 and 173.66 cm; k = 0.11 and 0.11; and t₀ = -3.62 and -3.33. The estimated age at 50% maturity for female Sandbar Sharks changed from 15 years to 12.49 years between the two time periods.

Sharks are considered top predators in many marine ecosystems and can play an important role in structuring community ecology. As a result, it is necessary to understand the factors that influence their abundance and distribution. This is particularly important as fishery managers develop management plans for sharks that identify areas that serve as essential fish habitat, especially nursery habitat. However, our understanding of shark habitat use in northeast Florida waters is limited. The goal of this study was to characterize the abundance and distribution of sharks in northeast Florida estuaries and to examine the effect of abiotic factors on shark habitat use. A bottom longline survey conducted from 2009 to 2011 indicated that 11 shark species use the estuarine waters of northeast Florida during the summer months. Atlantic Sharpnose Sharks Rhizoprionodon terraenovae, Blacktip Sharks Carcharhinus limbatus, and Bonnetheads Sphyrna tiburo were the most abundant species andmade up 81.4% of the total catch. Site, month, and bottom water temperature were the most important factors determining the presence and abundance of sharks and suggest both regional and seasonal variations in the use of northeast Florida waters. Depth, salinity, and dissolved oxygen were also important factors. Our data show that these waters serve as a nursery for Atlantic Sharpnose and Blacktip Sharks, with young-of-the-year and juveniles being present in the summer months. Limited tag—return data reveal that juvenile sharks remain in these waters throughout the summer and that some return in subsequent summers. This is the first study to characterize the abundance and distribution of sharks and identify potential nursery areas in northeast Florida estuaries.

Technological advances represent opportunities to enhance and supplement traditional fisheries sampling approaches. One example with growing importance for fisheries research is hydroacoustic technologies such as side-scan sonar. Advantages of side-scan sonar over traditional techniques include the ability to sample large areas efficiently and the potential to survey fish without physical handling-important for species of conservation concern, such as endangered sturgeons. Our objectives were to design an efficient survey methodology for sampling Atlantic Sturgeon Acipenser oxyrinchus by using side-scan sonar and to developmethods for analyzing these data. In North Carolina and South Carolina, we surveyed six rivers thought to contain varying abundances of sturgeon by using a combination of side-scan sonar, telemetry, and video cameras (i.e., to sample jumping sturgeon). Lower reaches of each river near the saltwater-freshwater interface were surveyed on three occasions (generally successive days), and we used occupancy modeling to analyze these data.We were able to detect sturgeon in five of six rivers by using these methods. Side-scan sonar was effective in detecting sturgeon, with estimated gear-specific detection probabilities ranging from 0.2 to 0.5 and river-specific occupancy estimates (per 2-km river segment) ranging from 0.0 to 0.8. Future extensions of this occupancy modeling framework will involve the use of side-scan sonar data to assess sturgeon habitat and abundance in different river systems.

The Cownose Ray Rhinoptera bonasus is an opportunistic predator of benthic invertebrates and has had a long history of negative interactions with commercial shellfish industries. Most recently, Cownose Rays have been implicated in negatively affecting the recovery of bay scallop Argopecten irradians stocks in North Carolina and oyster restoration and commercial aquaculture efforts in Chesapeake Bay. A mitigation attempt to decrease predation on shellfish has resulted in an unregulated fishery for Cownose Rays. Cownose Ray life history suggests that they are highly susceptible to overexploitation. We determined age, growth, and size at maturity for Cownose Rays collected in Chesapeake Bay. In total, 694 rays were used for the study: 246 males ranging in size from 30.0 to 98.0 cm disc width (DW) and 448 females ranging from 30.0 to 110.5 cm DW. The oldest individual observed was a female (107 cm DW) estimated at age 21. Our data suggested that Cownose Rays grow considerably faster during the first few years than has been previously reported, thus producing higher estimates of the growth coefficient k. The best-fit growth models (three-parameter von Bertalanffy models) estimated k-values of 0.2741 for males and 0.1931 for females. The large sample size and inclusion ofmany older animals (n = 119 rays over age 10) resulted in theoreticalmaximum size estimates that matched the observed sizes well. The median size at 50% maturity was 85–86 cm DW for males and females (corresponding to ages of ∼6–7 for males and ∼7–8 for females). Fecundity in Cownose Rays was typically one embryo per mature female, with a gestation period of 11–12 months. Our study confirms that the Cownose Ray is a K-selected species with late maturity, long gestation, and low reproductive potential, indicating that it could be highly susceptible to overexploitation.

Bycatch studies have been conducted in many fisheries in Georgia, but none has focused on the commercial pot fishery for blue crab Callinectes sapidus. The purpose of this study was to identify abundance and seasonality of finfish and invertebrate bycatch species in the commercial blue crab fishery in Georgia. Between November 2003 and December 2006, observers accompanied volunteer commercial blue crab fishers randomly selected from a list of willing participants. A total of 91 trips were observed, with 5,707 commercial blue crab pots sampled. Soak times, or fishing effort, ranged from 24 to 168 h, averaging 55.8 h/trap for each trip. The number of traps sampled each trip ranged from 5 to 163, with a mean of 62.7 traps per trip. We collected 306 finfish and 4,972 invertebrates in this study period. The most numerous finfish were Southern Flounder Paralichthys lethostigma (n = 52), Atlantic Spadefish Chaetodipterus faber (n = 50), Oyster Toadfish Opsanus tau (n = 50), Hardhead Catfish Ariopsis felis (n = 46), and Southern Kingfish Menticirrhus americanus (n = 37). The most numerous invertebrates species were hermit crabs Pagurus spp. (n = 2,341), spider crabs Libinia spp. (n = 532), stone crabs Menippe mercenaria (n = 438), channeled whelk Busycon canaliculatum (n = 1,570), and knobbed whelk Busycon carica (n = 25). The similarity of bycatch by season was compared using aMorisita similarity index, and results were that Southern Flounder, Atlantic Spadefish, Oyster Toadfish, spider crabs, channeled whelk, and stone crabs varied seasonally. Of all species observed, we conclude that channeled whelk populations may be impacted by this fishery.

Serial, cyclonic, mesoscale eddies arise just north of the Charleston Bump, a topographical rise on the continental slope and Blake Plateau, and characterize the U.S. outer shelf and upper slope in the region of the Charleston Gyre. This region was transected during the winters of 2000, 2001, and 2002, and hydrographic data and larval fishes were collected. The hydrodynamics of the cyclonic eddies of the Charleston Gyre shape the distribution of larval fishes by mixing larvae from the outer continental shelf and the Gulf Stream and entraining them into the eddy circulation at the peripheral margins, the wrap-around filaments. Over all years and transects (those that intercepted eddies and those that did not), chlorophyll a concentrations, zooplankton displacement volumes, and larval fish concentrations were positively correlated. Chlorophyll a concentrations were highest in filaments that wrapped around eddies, and zooplankton displacement volumes were highest in the continental shelf-Gulf Stream-frontal mix. Overall, the concentration of all larval fishes declined from inshore to offshore with highest concentrations occurring over the outer shelf. Collections produced larvae from 91 fish families representing continental shelf and oceanic species. The larvae of shelf-spawned fishes-Atlantic Menhaden Brevoortia tyrannus, Round Herring Etrumeus teres, Spot Leiostomus xanthurus, and Atlantic Croaker Micropogonias undulatus-were most concentrated over the outer shelf and in the continental shelf-Gulf Stream-frontal mix. The larvae of ocean-spawned fishes-lanternfishes, bristlemouths, and lightfishes-were more evenly dispersed in low concentrations across the outer shelf and upper slope, the highest typically in the Gulf Stream and Sargasso Sea, except for lightfishes that were highest in the continental shelf-Gulf Stream-frontal mix. Detrended correspondence analysis rendered groups of larval fishes that corresponded with a gradient between the continental shelf and Gulf Stream and Sargasso Sea. Eddies propagate northeastward with a residence time on the outer shelf and upper slope of ∼1 month, the same duration as the larval period of most fishes. The pelagic habitat afforded by eddies and fronts of the Charleston Gyre region can be exploited as nursery areas for feeding and growth of larval fishes within the southeastern Atlantic continental shelf ecosystem of the U.S. Eddies, and the nursery habitat they provide, translocate larvae northeastward.

Drastic increases or decreases in biomass often result in density-dependent changes in life history characteristics within a fish population. Acknowledging this phenomenon and in light of the recent biomass increase in Barndoor Skate Dipturus laevis, the current study re-evaluated the growth rate and sexual maturity of 244 specimens collected from 2009–2011 within closed areas I and II on Georges Bank, USA. Ages were estimated using vertebral band counts from skate that ranged from 21 to 129 cm TL. The von Bertalanffy growth function was applied to pooled age-at-length data. Parameter estimates from the current study of L_∞ = 155 cm TL and k = 0.10 represent a significant decrease from previously reported parameters of L_∞ = 167 cm TL and k = 0.14. In addition to changes in growth parameters, age at 50% maturity for both males (based on clasper length, testes mass, and percent mature spermatocytes) and females (based on data from shell gland mass, ovary mass, and follicle diameter) increased by 3 years and 4 years, respectively. Based on our results and the 10- to 12-year gap in the collection of samples, it is likely that Barndoor Skate within this region have exhibited pliability in life history parameters.

Commercial fishing is responsible for declines in both the abundance and biomass of many marine species(Ward and Myers 2005). The Marine Stewardship Council's (MSC) Sustainable Seafood Certification Programfocuses on fishery modifications to reduce such impacts on marine species and ecosystems. On the Nicoya Peninsulain northwestern Costa Rica, the Costa Rican nongovernmental organization Programa Restauración de TortugasMarinas has been working with artisanal fishers since 2007 to promote sustainable fishing practices, with the goalof applying for a sustainable fishery certificate from the MSC. To collect relevant data for the MSC application, wetested the selectivity of the hooks used in the artisanal fishery to determine how the fishery interacts with the targetspecies, the Spotted Rose Snapper Lutjanus guttatus, as well as nontarget, bycatch species.We constructed a longline composed of equal numbers of different sized hooks (the Mustad #8 “J” style hooks commonly used in the fishery as well as smaller #10 and larger #6 hooks). Decreasing the hook size led to higher catch rates of both Spotted Rose Snapper and most bycatch species, with no change in mean size of Spotted Rose Snapper. Increasing the hook size led to decreased catch rates of both Spotted Rose Snapper and most bycatch species and an increase in the meansize of Spotted Rose Snapper. The size range of the Spotted Rose Snapper caught on this gear did not exceed that ofthe artisanal fishery. This study suggests that the artisanal fishery is using an appropriately sized hook to minimizebycatch rates without unduly minimizing the catch rates of the target species, though increasing hook size couldexclude the smallest Spotted Rose Snapper from the fishery.

Recovery of loggerhead turtle Caretta caretta populations depends on many factors, including reducing anthropogenic mortality of adult turtles. Shrimp trawls are considered a major source of mortality for adult loggerhead turtles despite the mandatory use of turtle excluder devices. We modeled scenarios for reducing the likelihood of interaction between nesting adult loggerhead turtles and shrimp trawlers operating off the coast of Georgia during the nesting season (May–August). We used satellite telemetry and aerial surveys to describe the distribution patterns of nesting adult female turtles (2004–2005; n = 22) and shrimp trawls (1999–2005), respectively, across waters adjacent to the Georgia shoreline. Adult female turtles and shrimp trawlers both occupied state waters extensively during the nesting season. Turtles tended to have long, narrow home ranges that were located parallel to shore and that overlapped with the shrimp trawl distribution, which showed a slight grouping around deep channels. We modeled the efficacy of fleet reductions and spatial closures (accounting for fleet redistribution) in reducing shrimp trawler activity around loggerhead turtles. A comparison of spatial closures indicated that a large closure of state waters (∼200 km²) east of Sapelo and Blackbeard islands would reducemean trawler activity levels in turtle home ranges.We also found that fleet reductions of 50% or more reduced potential interactions between turtles and trawlers. Although spatial closures produced a net total reduction in turtle-trawler interactions, fleet reductions yielded a reduction in such interactions across the study area. We recommend that to reduce loggerhead turtle-trawler interactions, state agencies should consider a limited-entry system or some other means to limit the number of vessels operating within state waters.

Atlantic Tripletails Lobotes surinamensis support a popular recreational fishery along the coast of Georgia; however, Atlantic Tripletail residency and movements within Georgia estuaries have not been studied. Our objective was to describe estuarine movements and residency of Atlantic Tripletails in the Ossabaw Sound Estuary, Georgia. During summer in 2010 and 2011, large juvenile and adult Atlantic Tripletails (n = 32; 42.1–71.0 cm TL) were captured with traditional angling methods and received surgically implanted ultrasonic transmitters. Tagged individuals were detected within the estuary via a stationary array of acoustic receivers that monitored the estuary continuously from June 2010 through May 2012. Manual tracking was conducted with a portable hydrophone and homing. Atlantic Tripletails were detected in the estuary during March–November at sustained water temperatures above 21° C; tagged fish were not detected by the stationary array during any other period. Movements were highly correlated with tidal stage; 100% of the tagged fish moved upstream with flood tides and returned to the sound with the ebbing tide on a daily basis. Atlantic Tripletails were observed as far upstream as river kilometer 33. Our results from acoustic telemetry provide the first information on spatial and temporal habitat use by Atlantic Tripletails within the South Atlantic Bight and suggest that these fish (1) exhibit a high degree of residency in Georgia estuaries and (2) use a large portion of the estuary during their daily movements. Although estuarine habitat use appeared to be an important component of the species' life history, future studies of population dynamics and winter movements will be needed to obtain a better understanding of the potentially complex structure of Atlantic Tripletail stocks.

Many populations of Sockeye Salmon Oncorhynchus nerka in the eastern North Pacific Ocean experienced significant productivity declines that began about 1990, but there is no consensus on the mechanisms responsible. To better understand Sockeye Salmon survival trends, we examined the 50-year time series for two age-classes of Sockeye Salmon smolts from Chilko Lake in central British Columbia. Arranging survival time series for both age-classes by ocean entry year and combining them, weighted by a proxy model of sampling variance, reduced the sampling variance in the original age-1 smolt survivals sufficiently to indicate a linear trend of increasing survival from 1960 to 1990 that suddenly changed at or near 1991 to a lower and declining trend from 1992 to 2008. Neither density nor mean length influenced smolt survival. Returns in a given year were not good predictors of siblings returning in subsequent years. Time spent at sea increased linearly beginning around 1970. Although smolt survivals differed between ecosystem regimes, there was only the one clear pattern break about 1991. To improve our understanding of mechanisms, survival trends were compared with environmental indices that included catches and hatchery releases of potentially competing salmon from around the North Pacific Ocean. Smolt survivals were more similar to abundance indices of Sockeye Salmon, Chum Salmon O. keta, and Pink Salmon O. gorbuscha than to indices of global, regional, or local ocean climate. Our results are consistent with the hypothesis that salmon productivity in the North Pacific declined soon after 1990. We present a simple model to illustrate how increased competition at sea, related to the release of large numbers of hatchery salmon, in conjunction with changes in ocean productivity, may have played a significant role in improving Sockeye Salmon survivals while reducing their growth before 1991. After 1991, these factors may have acted to reduce survivals while the growth of survivors showed no effect.