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The award for best publication of the year is given to authors who are employees of the National Marine Fisheries Service and whose article is judged to be the most [...]

The award for best publication of the year is given to authors who are employees of the National Marine Fisheries Service and whose article is judged to be the most [...]

The National Marine Fisheries Service best scientific paper awards for 2006 were awarded to the following authors: Butler, John, Melissa Neuman, Deanna Pinkard, Rikk Kvitek, and Guy Cochrane The use [...]

The National Marine Fisheries Service best scientific paper awards for 2005 were awarded to the following authors: Chris J. Harvey Effects of El Nifio events on energy demand and egg [...]

The article announces the best publication of the year award given to several authors who are employees of the National Marine Fisheries Service and whose works had been published in "Fishery Bulletin" and "Marine Fisheries Review" journals including Darin T. Jones, John L. Butler and Pat F. Cryer.

The article announces the 2009 award for best publication given to the authors who are employees of the National Marine Fisheries Service including Jeffrey J. Polovina, Evan A. Howell and Phil Clapham.

We assessed the effect of survey effort reduction on the accuracy and precision of estimates of abundance for 4 commercially or ecologically important species with differing distributions observed in a bottom-trawl survey conducted in the Gulf of Alaska. Simulations from a spatiotemporal generalized linear mixed model based on historical observations of catch densities were used to evaluate the statistical robustness, measured in terms of coefficient of variation, relative bias, and relative root mean square error, of the abundance estimates and their variances. These metrics were used to compare estimates between the traditional design- based estimator and the alternative estimator, based on a vector autoregressive spatiotemporal model, at 4 different sampling densities, representing 2 historical and 2 theoretical sampling effort levels on either side of the historical range. The recent reduction in the density of survey sampling from 820 to 550 stations had only a modest effect on the performance metrics for both estimators for arrowtooth flounder (Atheresthes stomias), Pacific cod (Gadus macrocephalus), and Pacific ocean perch (Sebastes alutus). However, the effect on the abundance estimates for sablefish (Anoplopoma fimbria) was substantial. We attribute this difference in results to the wider depth range utilized by sablefish, which preferentially occupy the relatively under- sampled deep strata (>500 m), and to the truncated survey area at the reduced sampling levels where the deepest strata (>700 m) have been eliminated. [ABSTRACT FROM AUTHOR]

Blue catfish (Ictalurus furcatus) have been widely introduced throughout the United States and are invasive in Chesapeake Bay. Despite this proliferation, little is known about the diet of this large, predatory catfish. We used stratified random sampling to collect stomachs from 14,488 blue catfish in Chesapeake Bay. Canonical correspondence analysis (CCA) was used to identify key drivers of the diet of blue catfish, and generalized additive models (GAMs) were used to explore trends in rates of predation by blue catfish on depleted or commercially valuable native species, including American shad (Alosa sapidissima), blueback herring (A. aestivalis), alewife (A. pseudoharengus), American eel (Anguilla rostrata), and blue crab (Callinectes sapidus). Results of CCA reveal that diets were significantly correlated with season, salinity, and total length (TL) of blue catfish, and those from our GAMs reveal the circumstances associated with greater predation on these species. For example, we found that Alosa species were most susceptible to predation by large catfish (>600 mm TL) in freshwater areas during the month of April. This paper describes methods for identifying times, locations, and other circumstances that are associated with maximal predation rates upon certain taxa. The information gained from these approaches can be used to inform management strategies, with the goal of reducing effects of predation on specific organisms. [ABSTRACT FROM AUTHOR]

Descriptions of the lanternfish larvae of the subfamilies Lampanyctinae (12 species) and Notolychninae (1 species) that can be found in the Subtropical Convergence (STC) are presented: Bolinichthys supralateralis, Ceratoscopelus gr. townsendi, Lampadena sp., Lampanyctus alatus, L. ater, L. australis, L. gr. achirus, L. intricarius, L. festivus, L. pusillus, Lampanyctus sp. D, Lepidophanes guentheri, and Notolychnus valdiviae. Also provided is an identification key based on larval characters for all lanternfish subfamilies. We propose the use of a separate key for the postflexion larvae of all known genera of the round-eyed lanternfish subfamilies Diaphinae, Gymnoscopelinae, Lampanyctinae, and Notolychninae. For each genus, general characteristics of larval morphology are given. Species descriptions include the key characters for identification, variation in meristic characters, pigmentation, and other features important for diagnosis of Myctophidae at their larval stages. Photographs of the most important diagnostic features are provided for each species. The taxonomy of 4 problematic species in the area, C. gr. townsendi, Lampanyctus gr. achirus, L. intricarius, and Lampanyctus sp. D, is discussed. Preflexion, flexion, and postflexion stages of an unidentified Lampadena sp. from the northern limit of the STC are described for the first time; these larvae may belong to 1 of 3 species (L. dea, L. notialis, and L. speculigera) for which larvae have not yet been identified. The distribution of Lampanyctinae and Notolychninae in the STC is summarized. [ABSTRACT FROM AUTHOR]

Elongated rostra evolved in diverse animal groups as adaptations for feeding, defense, sensory perception, and reproduction. Sawfish rostra have tooth-like dermal denticles, referred to as rostral teeth, along their lateral margins. Embryos have a sheath, or covering, for the calcified rostral teeth during gestation, and it persists until after parturition. Little is known about the morphology and composition of the sheath. During 18 years of tagging juvenile smalltooth sawfish (Pristis pectinata), sheaths were documented for 36 neonates with stretch total lengths of 581-812 mm, and samples were collected from 6 specimens for laboratory evaluation. The multilayered, skin-like sheath, which cannot be easily removed manually, has a vascularized inner layer of connective tissue composed primarily of fibrous proteins (e.g., collagen, reticulin, and keratin) surrounded by an outer layer of columnar and spherical epithelial cells overlying a basement membrane. The columnar cells contain condensed chromatin and differentiate into the outermost spherical cells that contain carbohydrates. After birth, the sheath is shed evenly over 4 d, through sloughing and apoptosis, fully exposing the rostral teeth. The sheath is an ephemeral embryonic organ that protects the female and the embryos from injury during gestation and birth. [ABSTRACT FROM AUTHOR]

The Lebranche mullet (Mugil liza) is an economically important estuarine species found along the coast of Brazil. The southern population of this species ranges from the coast of the state of São Paulo (23°S) to the coast of Argentina (36°S). It migrates annually among estuaries in Argentina, Uruguay, and southern Brazil to reproduce in their marine spawning grounds (~26°S). We evaluated whether variations in the otolith chemical composition for fish acquired at nursery grounds can be used to make distinctions among 4 nursery areas of the southern population. Analysis of otolith microchemistry included concentrations of 9 elements: lithium (Li), magnesium (Mg), copper, zinc, strontium (Sr), cadmium, barium, lanthanum, and lead. When using random forest classification algorithms, the maximum accuracy of 96% in assignment of nursery habitat for Lebranche mullet between 2 groups (fish caught at nurseries in Brazil and fish migrating from waters of Uruguay and Argentina) was achieved with the combination of Li, Mg, and Sr. Our results indicate that the elemental composition of otoliths can be an important tool for establishing connectivity between nursery areas used by Lebranche mullet. We discuss the implications of this result for the structure of the population and the management of the mullet fishery in southern Brazil relative to the limitations of the methods we employed. [ABSTRACT FROM AUTHOR]

Crab traps have been used extensively in studies on the population dynamics of blue crabs to provide estimates of catch per unit of effort; however, these estimates have been determined without adequate consideration of escape rates. We examined the ability of the blue crab (Callinectes sapidus) to escape crab pots and the possibility that intraspecific crab interactions have an effect on catch rates. Approximately 85% of crabs that entered a pot escaped, and 83% of crabs escaped from the bait chamber (kitchen). Blue crabs exhibited few aggressive behavioral interactions in and around the crab pot and were documented to move freely in and out of the pot. Both the mean number and size of crabs caught were significantly smaller at deeper depths. Results from this study show that current estimates of catch per unit of effort may be biased given the high escape rate of blue crabs documented in this study. The results of this paper provide a mechanistic view of trap efficacy, and reveal crab behavior in and around commercial crab pots. [ABSTRACT FROM AUTHOR]

In this study, we examined whether otolith microconstituents are deposited seasonally in a manner similar to optical annulus formation and thereby can be used to validate age interpretations. In temperate species, seasonal temperature changes drive the formation of optical annuli, and we hypothesized that they similarly caused oscillations in microconstituent deposition. Using laser ablation inductively coupled plasma mass spectrometry analysis, we tested for periodicity in the deposition of barium (Ba), calcium, copper, magnesium (Mg), manganese (Mn), phosphorus (P), strontium, and zinc in otoliths and compared that periodicity to the periodicity of the annulus zonation (optical opaque and translucent zones). For this investigation of chemical annulus periodicity, we used black sea bass (Centropristis striata), a species with yearly optical annulus formation that has been validated. Periodicities in elemental profiles in otoliths from black sea bass were detected by using Lomb-Scargle periodogram analyses. Optical annulus formation aligned with Mg profiles, but periodicity in annular deposition of other elements--Ba, Mn, and P--was observed only after the first optical annulus, an outcome that is indicative of ontogenetic changes in habitat (from coastal to near-shelf waters) known to occur during the juvenile life stage of this species. Certain elements, such as Mg, identified through this otolith analysis and the periodogram analyses could be applied to species for which no validated aging procedure exists. [ABSTRACT FROM AUTHOR]

The article focuses on the guidelines for authors of the periodical "Fishery Bulletin" including the use of footnotes, literature cited section, and use of tables.

The article lists several guidelines for the authors in the publishing of the journal. The title page should include the full names of the authors and mailing addresses and the senior author's telephone, fax number, and e-mail address. The headings within each section must be short, depicts a logical sequence, and must abide by the rules of multiple subdivision. The figures within the journal must include line illustrations, photographs, and computer-generated graphs.

Abundance indices from fishery-independent surveys are preferred in stock assessments for their robust scientific designs that minimize uncertainty and bias. When sampling does not adhere to the design, researchers employ techniques such as imputation or standardization to improve accuracy and reduce bias. We examined 2 methods for adjusting for incomplete sampling within the Coastal Trawl Survey (CTS) of the Southeast Area Monitoring and Assessment Program--South Atlantic for 3 species commonly encountered in survey sampling, the Atlantic croaker (Micropogonias undulatus), bluefish (Pomatomus saltatrix), and white shrimp (Litopenaeus setiferus): design-based imputation of missing data and standardization through the delta-generalized-linear-model approach. Additionally, we determined the effect of modifying the seasonal component of the survey design through retrospective simulation. For all 3 species, standardization improved precision in annual abundance estimates relative to values estimated with the design-based method. When a stratum missed in sampling overlapped with an area or time of high variability for a species (e.g., 2019), standardization did not improve precision over the design-based method. Results from examination of the effects of dropping entire seasons, because of funding or logistical challenges, indicate that rotating which season is dropped was the best approach to balancing characteristics of each species. Overall, we recommend the standardization approach for accounting for missing data within the CTS time series. [ABSTRACT FROM AUTHOR]

Crustacean species are socioeconomically and ecologically crucial across the world. For crustaceans, as ectotherms, anthropogenic climate change threatens to significantly alter key life history characteristics, such as size at maturity and growth rate. Because crustaceans are difficult to age, length data are used in assessments of crustacean stocks; however, climate-induced changes in maturation and growth can greatly influence the performance of size-structured stock assessment models. We coupled individual-based and size-structured models for American lobster (Homarus americanus) off northeastern North America in the Gulf of Maine--to conduct a novel sensitivity analysis of the effects of maturity and growth-related input parameters on model outputs. For this analysis, we used a bottom-up approach (with parameters shifted independently) and a top-down approach (with parameters shifted jointly as they were predicted to be influenced by climate change). We found that our American lobster stock assessment model is resilient to relatively extreme shifts in biological input parameters. For size-structured modeling in assessments of crustacean stocks, we recommend the expansion of sensitivity analyses to include evaluation of the influence of climate-driven changes on input parameters based on time-varying life history traits. [ABSTRACT FROM AUTHOR]

The Dolly Varden (Salvelinus malma), an iteroparous, facultatively anadromous Pacific salmonid, displays diverse life history and migration patterns. Using otolith microchemistry, we inferred that individuals sampled in the Nushagak Commercial Salmon Fishery Management District, Alaska (sample size [n]=30; mean fork length=597 mm), had entered saltwater at ages 4-7 and were in their first (26%) or second (74%) summer at sea. Most (88%) of the fish that had spent 2 summers at sea migrated in consecutive years, but 2 of them skipped a migration to marine waters, remaining in fresh water for an additional year after migrating to sea in their first year. Only 15% of the individuals with 2 summers at sea had anadromous mothers. In contrast, conspecifics sampled on the other side of Bristol Bay in the Egegik Commercial Salmon Fishery Management District started migrating at an earlier age, migrated more often, and more often had anadromous mothers. Together, these results highlight the differences in life history among Dolly Varden and indicate that freshwater rather than marine conditions influence life history patterns, at least for fish within the Nushagak District. [ABSTRACT FROM AUTHOR]

Specimens of the spotted moray (Gymnothorax moringa) were obtained from fishery-dependent and fishery-independent sources off the Atlantic coast of the southeastern United States from May 2005 through April 2007. A total of 491 individuals, ranging in total length (TL) from 556 to 1267 mm, were collected; age estimates ranged from 4 to 23 years, with a mean of 12.3 years. Females attained greater ages and had a significantly greater mean age than males. Length at age of males was greater than that of females at all ages but was significantly greater only at ages 9, 10, 12, and 17. In size classes with lengths greater than 900 mm TL, males were significantly heavier than females. The overall male-to-female sex ratio of 1:1.09 did not significantly differ from 1:1. All specimens were examined histologically, and none were immature. Spawning females were collected from late April through February, and estimates of spawning periodicity (24-31 d) indicate that a female could spawn up to 12 times during a spawning season. Males were in spawning condition throughout the year, with the exception of March, when all individuals were in regressing condition. Two individuals had both testicular and ovarian tissue; however, histological evidence indicates that this species is likely gonochoristic. [ABSTRACT FROM AUTHOR]

Opah (Lampris spp.) are commercially valuable, non- target fish that are regularly landed in pelagic longline fisheries in the central and eastern North Pacific Ocean. Genetic studies have confirmed 2 species in the region: bigeye Pacific opah (L. megalopsis) and smalleye Pacific opah (L. incognitus). Spatial distributions of each species are not well-defined, and little is known about species- specific catch distributions because the 2 species are difficult to distinguish visually. The objectives of this study were to characterize spatiotemporal patterns of opah landings by using catch per unit of effort (CPUE) from logbook and observer data, for the period 1995-2018, and geneticsbased species identifications. Results from generalized additive models indicate that bigeye Pacific opah dominate west of 140°W and that smalleye Pacific opah dominate waters east of 130°W (dominance is defined as a proportion of catch ≥0.7). The deep- set pelagic longline fishery had higher opah CPUE than the shallow- set fishery across the geographic range of these fisheries. Opah CPUE increased from west to east on both longline gears, indicating higher overall opah CPUE in the eastern regions of both fisheries, primarily dominated by smalleye Pacific opah. Opah CPUE also increased over time as the Hawaii- based longline fisheries expanded eastward. The results of this study highlight the need for speciesspecific catch data and will inform management of opah species. [ABSTRACT FROM AUTHOR]

Pacific salmon (Oncorhynchus spp.) are important to the ecology, economy, and cultures of the Pacific Northwest. Many populations of Pacific salmon in the Pacific Northwest are declining because of poor marine survival. We evaluated the role of Steller (Eumetopias jubatus) and California (Zalophus californianus) sea lions as predators of Pacific salmon. Roughly, half of the 1330 metric tons (t) of Pacific salmon eaten by Steller sea lions per year and of the 1220 t of Pacific salmon eaten by California sea lions per year in northwest Washington during 2010-2013 were coho salmon (O. kisutch). The response of Steller and California sea lions to the large run of pink salmon (O. gorbuscha) in 2011 was less than expected. Sea lions of these species rarely ate large (roughly ≥50 cm in total length) Chinook salmon (O. tshawytscha), indicating that they have limited direct competition for prey with the southern resident distinct population segment of killer whales (Orcinus orca). Combined, California and Steller sea lions in northwest Washington consumed a mass of coho salmon similar to that landed by commercial fisheries in Washington State. More work on modeling the effect of the predation by California and Steller sea lions on salmon populations, particularly for coho salmon, is needed to better evaluate the conservation and productivity of Pacific salmon. [ABSTRACT FROM AUTHOR]

This study, which included examination of the distribution and life history and a stock assessment of the flathead lobster (Thenus orientalis), is the first of its kind in the waters of Saudi Arabia in the Arabian Gulf, also known as the Persian Gulf. The flathead lobster is widely distributed in this region, although it is more abundant in the central and northern Arabian Gulf. Carapace lengths at 50% and 95% maturity are 59 and 65 mm for females and 58 and 71 mm for males. The fecundity of 4 berried females ranged from 26,000 to 76,000 eggs per spawning, and the fertilization rate exceeded 97%. Length-frequency data were consistent with just 2 cohorts, indicating that this species has a short life span and high growth coefficient (K=0.846 year-1). Large fishing boats (called dhows) accounted for more than 98% of the total landings. Estimates of natural mortality rates from use of generalized depletion models have high statistical precision and a magnitude compatible with short life history. In addition, abundance levels estimated with the depletion model are sufficient to support a sustainable small- scale fishery either as bycatch of shrimp trawlers or as a resource targeted with specialized gear. A targeted fishery for flathead lobster could be set during the off months of the shrimp trawl fishery (February-July), reducing interference with the reproduction cycle. [ABSTRACT FROM AUTHOR]

Fishery observer records from 2001 through 2016 were examined to document interactions, injuries, and mortalities of killer whales (Orcinus orca) associated with fishing operations in Alaska. Although widespread throughout Alaska, the highest numbers of such events occurred in the southeastern Bering Sea. Killer whales of the resident ecotype feeding on catch or discarded catch and fishermen using whale deterrence measures represented 96% (number of interactions [n]=3110) of all interactions examined in this study (n=3245). We found that 87% (n=2817) of all interactions occurred during longline operations. Both minor and serious injuries were documented. Twenty-seven killer whales were reported dead, but additional mortalities are assumed. Most whales killed were residents; however, 3 transient whales were also taken. Because killer whale populations are relatively small, a low level of mortality may significantly affect populations, especially if multiple sympatric stocks are shown to exist. Given the long history (i.e., over 6 decades) that Alaska killer whales have had with fishing operations, it is likely that these interactions will continue. [ABSTRACT FROM AUTHOR]

The diets of Steller (Eumetopias jubatus) and California (Zalophus californianus) sea lions in northwest Washington are poorly documented. We hypothesized that these species exploit the same prey in Washington because they are both generalist predators that utilize the same haul-out sites and are similar in behavior and body size. We analyzed 776 samples of scat from Steller sea lions and 263 samples of scat from California sea lions collected throughout each year during 2010-2013. The aim of this analysis was to characterize seasonal and annual diets, estimate biomass of prey consumed, and evaluate dietary niche overlap. Steller and California sea lions ate diverse diets that varied seasonally and annually. Primary prey groups for both sea lion species were Clupeidae, Salmonidae, Sebastidae, Rajidae, Pleuronectiformes, Squalidae, and Merlucciidae. We estimated that Steller sea lions ate 11,327 metric tons (t) (standard deviation [SD] 1600) and that California sea lions ate 9063 t (SD 4098) of prey per year during our study. We found significant dietary niche overlap between California and Steller sea lions that feed in northwest Washington. [ABSTRACT FROM AUTHOR]

An unusually strong year class of goosefish (Lophius americanus) was first observed in the spring of 2015, and the length mode for this particular cohort remained evident for several years. We collected monthly samples from within this length mode over a period of 3 years and considered them fish with known ages for validating ages estimated by using illicia and vertebrae. Recent research had found vertebral ages for goosefish to be inaccurate, and a method in which illicia are used for Lophius species in Europe seemed promising. However, ring counts from illicia matched the known age only 50% of the time and were not replicable (9% agreement). Ring counts from vertebrae never matched the known age but were replicable in 68% of samples. Marginal increment analysis of illicia from fish that matched the known age provided evidence that one annulus is formed on the illicium in spring or summer of each year for fish aged from 1 to 2 years. Because of the low accuracy of age estimates made with both illicia and vertebrae, as well as the high bias of aging with vertebrae, we concluded that the methods based on these structures did not provide useful age estimates of goosefish. The observed growth rate, based on the progression of the length mode during our study, was much faster than the growth rates based on vertebral ages. [ABSTRACT FROM AUTHOR]

Bycatch studies have largely ignored population level effects on fish species of little commercial interest. Here we analyze bycatch of the lined seahorse (Hippocampus erectus) in the bait-shrimp trawl fishery in Hernando Beach, Florida, providing the first fisheries data for this species. Based on catch per unit of effort (CPUE), size, sex, and reproductive status of trawled H. erectus, 1) approximately 72,000 seahorses were caught annually by this fleet, from a population of unknown size, 2) trawling affected population cohorts differentially because of temporal and spatial variation in CPUE and population size, and 3) a greater proportion of females than males was removed in trawling. Our findings suggest that trawling may affect seahorse populations through direct mortality, social disruption, and habitat damage. However, the lack of specific abundance or catchability estimates for H. erectus means that the precise impact of trawling on this fish remains uncertain. This paper focuses attention on the need for research and monitoring of small fishes that are caught incidentally in nonselective gear. [ABSTRACT FROM AUTHOR]

Underwater vehicles have many advantages for sampling fish; however, estimates can be biased by behavioral responses to sampling gear. To evaluate avoidance and attraction bias we assessed changes in fish abundance relative to a variety of sampling vehicles during transit through a test bed. Fish species were classified into five attraction and avoidance categories according to the behavioral responses exhibited. We observed that the rigor of behavioral responses varied by vehicle, vehicle range and altitude, transect number, and habitat complexity. The effect of each variable is dependent on behavioral guild, but vehicle range was the most consistent predictor of changes in abundance regardless of vehicle. Vehicles that surveyed the environment at higher relative altitudes off the seafloor and at slower speeds elicited weaker behavioral responses regardless of whether those reactions were attraction or avoidance. The test-bed approach allowed assessment of responses that cannot be observed from the perspective of a sampling vehicle but was restricted by the number of species-specific interactions observed. Despite success in estimating behavioral responses, calibrating the effect against known densities of fish was not possible. However, the method used is a robust way for future investigations to quantify species-specific responses for gear calibration and to provide information that aids in the calculation of fish abundance. [ABSTRACT FROM AUTHOR]

Inaccurate age determinations can have serious effects on age-structured stock assessments that are used to manage fish populations. A recent push toward using an age-based model for the northern stock of black sea bass (Centropristis striata) led to an increase in direct aging effort in the northeastern United States. Yet, no large-scale otolith age validation study for this stock exists. We examined the annual periodicity of otolith growth in this species through marginal increment analysis with otoliths of fish from 3 age groups (fish of ages 1-2, ages 3-4, and ages 5+) and from 2 regions, north and south of the Hudson Canyon. Additionally, we validated the assignment of the first annulus through modal length-frequency analysis of young-of-the-year fish. The marginal increment ratio differed between age groups throughout the year, supporting the separation of these samples for age validation purposes. Higher ratios were observed in black sea bass from the region south of the Hudson Canyon throughout most of the year; however, fish from north of the canyon appear to accrete more otolith material during winter. Annual growth increments were deposited once per year, in spring or early summer, for all fish. In addition, absolute age was validated for the first time for this stock. [ABSTRACT FROM AUTHOR]

The Gulf sturgeon (Acipenser oxyrinchus desotoi) is an anadromous fish found in drainages of the Gulf coast from Louisiana to Florida and is federally listed as threatened under the Endangered Species Act. Estimates of abundance of adult Gulf sturgeon from several studies have been reported, but direct quantification of juvenile abundance has not been attempted--although such information regarding annual recruitment and juvenile population trends is critical. Our objectives were to quantify recruitment of Gulf sturgeon in the Apalachicola River in Florida by estimating age-1 juvenile abundance and to investigate their survival. During May-August in 2013- 2018, we used entanglement gear to conduct a mark-recapture assessment of juvenile Gulf sturgeon. Using Huggins closed population models, we estimated that the Apalachicola River produces 28-210 age-1 juveniles annually (mean: 70 individuals [standard deviation 69.4]). Acoustic telemetry data collected from a subset of age-1 fish indicate that the study area was closed during sampling. We conservatively estimated overwinter survival on the basis of detections and recapture of age-2+ fish acoustically tagged at age 1. Survival varied among years from 33% to 90%. These results indicate that direct estimates of recruitment of Gulf sturgeon to age 1 are feasible, but it is difficult to determine whether this population is recruitment limited without similar data for other populations of Gulf sturgeon. [ABSTRACT FROM AUTHOR]

Many rockfishes (Sebastes spp.) inhabit rugged areas of seafloor that are inaccessible to survey trawl gear. Their utilization of such habitat makes estimation of their abundance difficult. Furthermore, it is often difficult to assess whether habitat is trawlable or untrawlable and to estimate the spatial extent of both habitat types. To help determine trawlability for the continental shelf in the Gulf of Alaska, we used multibeam sonar data collected in the area during 2011, 2013, and 2015. These data were used to derive 3 characteristics of the seafloor: oblique incidence backscatter strength (Sb oblique), seafloor ruggedness, and bathymetric position index. Habitat type was categorized as trawlable or untrawlable through analysis of video from deployed drift cameras. We tested the effectiveness of the use of these seafloor characteristics in prediction of habitat trawlability with 4 types of models: generalized linear model, generalized additive model, boosted regression tree, and random forest. All 4 models perform moderately well at predicting trawlability across the shelf, and results from all of them indicate that Sb oblique is the most important characteristic in discriminating between trawlable and untrawlable habitat. These results indicate that multibeam sonar data can help determine habitat type, information that in turn can help improve habitat-specific estimates of biomass of marine fish species. [ABSTRACT FROM AUTHOR]

The genetic population structure of the polkadot skate (Dipturus chinensis) around Japan was examined by using mitochondrial (mt) cytochrome (cyt) b gene sequences and polymorphic microsatellite (simple sequence repeat [SSR]) loci. Results of phylogenetic analysis based on mt cyt b gene sequences reveal 2 major lineages, clades A and B. Clade A consists of populations in the Sea of Japan and the East China Sea. Clade B contains populations in the Pacific Ocean and is divided into 2 subclades, clades B1 and B2, which correspond to the populations along the southern and northern coasts of Japan, respectively. This genetic differentiation is also supported by results from SSR analysis. The divergence of clades A and B may reflect isolation of the East China Sea from the Pacific Ocean in the Early Pleistocene. After diverging from clade A, clade B might have extended its distribution northward along the Pacific coast of Japan and divided into clades B1 and B2 in the Middle Pleistocene. The polkadot skate is clearly structured into 3 genetically discrete populations around Japan that should be treated as independent management units for management of this species in the future. [ABSTRACT FROM AUTHOR]

The trophic ecology of 7 key species of Gadiformes, the silvery pout (Gadiculus argenteus), Mediterranean bigeye rockling (Gaidropsarus biscayensis), European hake (Merluccius merluccius), blue whiting (Micromesistius poutassou), Mediterranean ling (Molva macrophthalma), greater forkbeard (Phycis blennoides), and poor cod (Trisopterus minutus), in the western Mediterranean Sea was explored. A total of 3192 fish stomachs were examined during 2011-2017 to investigate ontogenetic shifts in diet, trophic interactions (both interspecific and intraspecific), and feeding strategies. The results from applying multivariate statistical techniques indicate that all investigated species, except the Mediterranean bigeye rockling and poor cod, underwent ontogenetic dietary shifts, increasing their trophic level with size. The studied species hold different trophic positions, from opportunistic (e.g., the Mediterranean bigeye rockling, with a trophic level of 3.51) to highly specialized piscivore behavior (e.g., the Mediterranean ling, with a trophic level of 4.47). These insights reveal 4 different feeding strategies among the co-occurring species and size classes in the study area, as well as the degree of dietary overlap. Such information on ecological patterns within a fish assemblage, including species interactions, is often requested by those who aim to implement ecosystem management. Therefore, these findings can be used to improve management of sustainable fisheries in this region. [ABSTRACT FROM AUTHOR]

Spiny dogfish (Squalus acanthias) are traditionally aged by counting band pairs on dorsal-fin spines; however, wear and tear of the spines make obtaining accurate age estimates of older spiny dogfish difficult. Vertebral centra are an alternate structure that can be used to estimate age, but success in their use has been varied. We conducted a tag-recapture study using oxytetracycline injections to validate annual deposition in both dorsal-fin spines and vertebral centra of spiny dogfish. When band pairs in vertebral centra were used, time at liberty was significantly underestimated. Additionally, band-pair counts were found to change along the vertebral column of an individual, further refuting the use of vertebral centra to generate age estimates. Band-pair deposition in dorsal-fin spines was confirmed to be annual in spiny dogfish at liberty for up to 2.6 years. Dorsal-fin spines should continue to be used to age spiny dogfish, and vertebral centra are not a viable alternative. [ABSTRACT FROM AUTHOR]

Postflexion and transformation stages of the Diaphus ostenfeldi in the southwestern Pacific Ocean are described for the first time. Identification to the species level was based on tracing characters from fully formed, large metamorphic specimens backward to smaller specimens. It was found that larval D. ostenfeldi =9.5 mm standard body length (SL) can be characterized by a unique character within the genus Diaphus, namely the presence of melanophores at the dorsal fin base and between branchiostegal rays. Metamorphosis in larvae of this species occurs at a much longer body length (~20 mm SL) than in larvae of other species of this genus. [ABSTRACT FROM AUTHOR]

Networks of no-take fishery reserves have emerged as a tool for managing deepwater fish species. In Hawaii and elsewhere, such areas are used to manage deepwater snapper species. However, little is known regarding the movements of these species relative to protected areas. We used passive acoustic telemetry to track crimson jobfish (Pristipomoides filamentosus), also known as opakapaka, in one of Hawaii's bottomfish restricted fishing areas to understand the size required for a reserve to protect this species. From January 2017 through January 2018, 179 fish were tagged. Only 10 fish were classified as alive on the basis of movements indicated by detections in tracking data (tracks). For these fish, the median time between the first and last detection of an individual on an acoustic receiver array was 414.5 d with a mean number of detections per individual of 28,321. Linear estimates of home range averaged 3.7 and 6.0 km in conservative and optimistic scenarios, smaller than the median linear habitat dimension of Hawaii's reserves. Fish were detected within the reserve on 97% or more of the days they were tracked. These results indicate that current reserves in Hawaii are likely sufficient in scale to confer positive biological benefits to opakapaka that reside within their borders. [ABSTRACT FROM AUTHOR]

The effects of barotrauma and other capture-related factors on the discard mortality of black sea bass (Centropristis striata) are poorly understood. The objective of this study was to estimate the discard mortality rate for black sea bass in the winter deepwater recreational fishery off New Jersey and to evaluate if swim bladder venting can reduce discard mortality. A total of 1823 fish were sampled at multiple depths (45, 58, and 67 m) from November 2016 through March 2017. To estimate discard mortality at a depth of 45 m, 96 individuals were tagged with acoustic transmitters and monitored with acoustic receivers. The majority (95%) of fish captured across all depths exhibited effects of barotrauma, which were more prevalent at greater depths. Results from longitudinal survival analyses indicate that venting was the most significant predictor of mortality at a depth of 45 m, with the estimated mean discard mortality rate being lower for vented (20%) than non-vented (49%) fish. Fight time had the largest statistical influence on the mortality of non-vented fish, whereas longer fight times (>54 s) resulted in higher mortality at a depth of 45 m. Discard mortality may have been higher at greater depths, but venting and other recommended practices can mitigate mortality at all depths sampled. [ABSTRACT FROM AUTHOR]

We present data on the morphology of the larval stages of lanternfish species (Myctophidae) in the central North Atlantic Ocean. This work is based on materials collected during 2 cruises in the North Atlantic Ocean from the equator to latitude 30°N in 2016 and 2018. Several larvae obtained in other geographical areas were used for identification. In total, at least 33 species of the Myctophidae were found in the study area. We provide descriptions of those species whose early development was not previously known and of those species whose morphology differs from those already described in literature: roundnose lanternfish (Centrobranchus nigroocellatus), stubby lanternfish (Bolinichthys supralateralis), Diaphus sp. 1, Nannobrachium sp. 1, noble lanternfish (Lampanyctus vadulus), and Lampanyctus sp. 1. The characteristics on which these determinations are based are discussed. [ABSTRACT FROM AUTHOR]

Prompted by recent concern about the stock status of the shortfin mako (Isurus oxyrinchus) in the North Atlantic Ocean, we examined reproductive data from 731 individuals (351 females and 380 males) collected by 3 scientific organizations to improve estimates of size and age at maturity. Males ranged in size from 70 to 283 cm fork length (FL) and females from 71 to 338 cm FL. Females matured between 263 and 291 cm FL, with an estimated median length at maturity (L50) of 280 cm FL and a median weight at maturity (WT50) of 275 kg. Males matured between 173 and 187 cm FL, with an L50 of 182 cm FL and WT50 of 64 kg. Catch records from 4 international programs were also examined to investigate spatiotemporal variation in the distribution of life history stages based on updated size-at-maturity estimates and to identify potential parturition and nursery grounds. These records identified the Gulf of Mexico and the eastern North Atlantic Ocean off Portugal as birthing and nursery areas, with the most important nursery area occurring in the western North Atlantic Ocean. [ABSTRACT FROM AUTHOR]

Invasive red lionfish (Pterois volitans) have spread rapidly throughout the northern Gulf of Mexico (GOM) partly because of their high growth rate. Red lionfish were collected from the northern GOM across 3 ecological regions from 2012 through 2015. For male and female red lionfish, relationships between weight and total length (TL) were different by ecological region. Males achieved a greater mean weight adjusted for TL (333.6 g [standard error (SE) 3.6]) than females (195.1 g [SE 3.7]). A subsample of 1607 pairs of sagittal otoliths (from 744 males, 716 females, and 147 fish of unknown or undetermined sex) was used to assign ages. Ages ranged from 0.0 to 4.5 years (mean: 1.4 years), and these estimated ages and the dates of capture for specimens confirm the presence of red lionfish in the northern GOM in 2008, 2 years prior to the first detection of this species there. There were differences in age and growth between sexes within and among ecological regions, with males achieving higher growth rates and larger asymptotic lengths than females (all comparisons: P<0.01). These findings, coupled with other life history information, aid in discerning differences in distribution of red lionfish populations and are essential for creating management plans for mitigation of their effects on ecosystems. [ABSTRACT FROM AUTHOR]

We assessed the utility of an alternative method of video analysis for generating data for sharks and compared observations of sharks from the use of baited remote underwater video stations (BRUVS) with observations made by scuba divers during surveys conducted simultaneously with BRUVS video recordings. Videos were made off east-central Florida as part of a fishery-independent trap-video survey of fish species in hard-bottom reef habitats. In videos from 25 of 72 sites, we observed sharks, including the nurse (Ginglymostoma cirratum), tiger (Galeocerdo cuvier), spinner (Carcharhinus brevipinna), sandbar (C. plumbeus), Atlantic sharpnose (Rhizoprionodon terraenovae), bull (C. leucas), and lemon (Negaprion brevirostris) sharks. In contrast, divers observed 3 species of sharks at 5 sites. We conclude that video observations are superior to diver observations for detecting sharks. Rapidly viewing an entire video (the alternative method), rather than viewing only a 20-min segment (the standard protocol), has the potential to increase the number of sites where sharks are observed and the number of shark species that are observed in video analysis (as it did, by 400% and 40%, respectively, in this study). This method holds promise for providing critical information without extraction of specimens and for aiding stock assessments and essential fish habitat delineation for these important predators. [ABSTRACT FROM AUTHOR]

A standard method used by fisheries managers to decrease catch and effort is to shorten the length of a fishery; however, data on recreational angler response to this simple approach are surprisingly lacking. We assessed the effect of variable season length on daily fishing effort, measured by using numbers of boat launches per day, anglers per boat, and anglers per day from video observations, in the recreational sector of the federal fishery for red snapper (Lutjanus campechanus) in coastal Alabama. From 2012 through 2017, season length fluctuated from 3 to 40 d. Daily effort, measured by using mean number of boat launches per day (coefficient of multiple determination [R2]=0.58) and mean number of anglers per day (R2=0.67), increased linearly with season shortening, indicating effort compression. In 2017, 2 seasons were allowed: an early season (3 d) and an unanticipated late season (39 d). Daily effort decreased during the late season, indicating that effort can also be relaxed if anglers anticipate longer seasons. Model fit for mean number of anglers per day improved with the addition of a daily wind factor (R2=0.94). The results of this study indicate that responses of anglers to changing fishing seasons are dynamic. [ABSTRACT FROM AUTHOR]

The porbeagle (Lamna nasus) is a slow-growing, late-maturing, long-lived pelagic shark that inhabits cold temperate waters. Previous research based on specimens collected from the western North Atlantic Ocean has indicated that this lamnid shark has an annual reproductive cycle. However, the results of a recent evaluation of reproductive tracts from a geographically segregated group of porbeagles within the western North Atlantic Ocean indicate the presence of females in a resting stage of maturity. The observation of a resting stage has implications not only in the reproductive cycle, biennial versus annual, of this species but also in the lifetime productivity. This finding indicates that this shark follows the typical lamnid resting period between pregnancies, a period that would decrease the lifetime output of young sharks and their resilience to direct and indirect fishing pressure. [ABSTRACT FROM AUTHOR]

Age underestimation of many shark species, such as the sandbar shark (Carcharhinus plumbeus), has been proven with age validation methods including bomb radiocarbon dating, oxytetracycline (OTC) injection, and tagrecapture data. Validation studies indicate that band-pair deposition in vertebral centra may not be directly related to time, especially in older individuals of a species. In this study, vertebrae from tagged, OTCinjected, and recaptured sandbar sharks were examined to determine if band-pair deposition past the OTC mark matched time at liberty. In 6 of 8 OTC-injected sharks at liberty for >1 year, band-pair count past the OTC mark underestimated time at liberty by 24-58%. Additionally, growth rates derived from tag-recapture data were slower than those described by previously published vertebral band-pair growth curves but were similar to those predicted by previous bomb radiocarbon dating and OTC results from this study. Together, the results from these studies indicate that modeling tag-recapture data may be more accurate for age determination in elasmobranchs given that band-pair counts on vertebral centra do not coincide with age throughout life. Analyses indicate that sandbar sharks may be less productive than previously understood. [ABSTRACT FROM AUTHOR]

Stocks of red snapper (Lutjanus campechanus) exhibited a dramatic decline in abundance in the northern Gulf of Mexico (GOM) between 1960 and 1991; management regulations implemented since 1991 have resulted in a modest recovery. To examine potential temporal and regional changes in reproductive parameters of female red snapper during recovery of the stock, we used meta-analytical models to analyze data collected during 1991-2017 throughout the northeastern (Florida, Alabama, Mississippi) and northwestern (Louisiana and Texas) GOM; no data were available for 2003-2008. Peak red snapper spawning occurred from June through August throughout the time period, and a high probability (>75%) of spawning occurred during May from 1995 through 2017. The reproductive season was estimated to average 4.5 months from 1994 through 2017. Increases in spawning interval were estimated across time in the northwestern region (2.3-4.7 days between spawnings from 1992 through 2015) and for regions combined (2.4-2.9 days from 1991 through 2017) but showed no changes in the northeastern region (2.3-2.4 days from 1991 through 2017). Relative batch fecundity generally decreased from 1991 through 2017 for all models; however, this decrease was more notable in the northwestern GOM than in the northeastern GOM after 2013. Our analyses suggest evidence of reproductive compensation, particularly because the estimated changes in reproductive parameters were more pronounced in the northwestern GOM. [ABSTRACT FROM AUTHOR]

The daily deposition of growth increments within both sagittae and lapilli was validated for known-age laboratory-reared (18°C) larval northern pike (Esox lucius) (9–33 mm in standard length [SL]) sampled 1, 7, 14, 22, and 28 days after hatching. The mean otolith length at hatching was 58.1 μm (standard deviation [SD] 4.32) for sagittae (no. of larvae sampled [n]=30) and 39.04 μm (SD 4.04) for lapilli (n=30). For both sagittae and lapilli (the otoliths of which were examined without polishing), increments were formed daily and the first increment was deposited at time of hatching. The relationship of otolith size to fish size was linear for lapilli and exponential for sagittae. The size of the sagittae increased more than that of the lapilli at about 9 days after hatching—a size increase that corresponded with an increase in larval wet weight. The age of larval northern pike was moderately difficult to determine from otoliths; the difficulty varied according to the size of the larvae. Sagittae are preferable for fish larvae of up to approximately 25 mm SL, but for larger individuals, lapilli are more suitable. On some of the otoliths (79% of sagittae and 18% of lapilli), a “stress ring” was deposited that corresponded with the time of sampling from the aquaria. [ABSTRACT FROM AUTHOR]

Many studies underscore the importance of incorporating the effect of environmental data within a life-history-stage-specific framework for determining the recruitment and survival of small pelagic fish. The recruitment of anchovy (Engraulis encrasicolus) in the Gulf of Cádiz (NE Atlantic) is sensitive to the effect of intense easterlies, stratification of the water column, and discharges from the Guadalquivir River on early life stages. As a proof of concept, we have developed the basis for a new Bayesian model with a dual time step resolution: monthly for juveniles and adults, and weekly for earlier life stages. This dual time step resolution resolves environmental effects on prerecruits while simulating the effect of fishing on recruits. Our estimates for juvenile abundances are validated with field data. The Bayesian framework accounts for the uncertainty, thus providing consistent length-frequency estimates and a plausible environmentally driven stock-recruitment relationship. [ABSTRACT FROM AUTHOR]

Design-based estimators, which have well known statistical properties, exist for random sampling survey designs and provide unbiased estimates of the mean and variance of summary catch statistics. Although application of these estimators to fixed-station surveys is not technically valid, they can result in unbiased differences between years if the data exhibit spatial persistence A persistent system is one in which the differences in relative abundance of a population that are recorded at fixed stations are consistent from year to year (i.e., there is no interaction between station and years in a 2-way classification). In a fully persistent system, the changes in relative abundance derived from fixed stations will be unbiased. In this study, the persistence in relative abundance data collected from a fixed-station survey intended to monitor juveniles of economically important species is evaluated. The results can be used to infer those species for which changes in relative abundance estimated from fixed-station surveys will be more accurate than changes in relative abundance estimated from random surveys. [ABSTRACT FROM AUTHOR]

Gulf menhaden (Brevoortia patronus) produce one of the largest U.S. fisheries, yet information on reproductive dynamics of the stock is sparse. Males and females reach 50% maturity at 140.8 and 137.2 mm fork length, respectively and recruit into the commercial fishery at this size. Analysis of fishery-dependent data from 1964 through 2014 indicated that somatic condition was lower during the late 1980s and late 2000s and that reproductively active fish from 2014 were significantly larger and had greater gonadosomatic index values than those from 1964 through 1970. Histological analysis performed on fish from 2014 through 2016 revealed spawning-capable and actively spawning fish of both sexes from early October through mid- March. Females have indeterminate fecundity, are batch spawners, and spawn every 2.1-4.3 days, although oocyte recruitment shows some characteristics of determinate fecundity. Mean relative batch fecundity was 107.8 eggs/g ovary-free body weight (standard error 17.1). Estimates from age-structured assessment models based on updated fecundity and maturity measures resulted in a 100-1000× greater production of eggs than previous estimates. Model output, including the number-at-age, age-specific fishing-induced mortality, and spawners-per-recruit are sensitive to alterations in age-specific annual fecundity. Therefore, updated estimates of Gulf menhaden reproductive dynamics can affect assessments of the stock. [ABSTRACT FROM AUTHOR]

Geomorphological assessments were conducted and passive acoustic recordings were collected from 2012 through 2014 at 3 recently identified spawning aggregations of the black grouper (Mycteroperca bonaci) in Puerto Rico and southern Florida. A time series of courtshipassociated sounds (CASs) by black grouper were analyzed in relation to lunar and diel periodicities, water temperature, and tidal stage. Analysis of CAS recordings indicated similar temporal patterns at the 3 spawning aggregations. Spawning season was correlated with decreased water temperature. Within the spawning season, CAS production was influenced significantly by lunar and diel periodicities and sound production peaked between the last quarter and new moons during evening hours. The data from this study also indicate a potential correlation with tidal stage. Temporal patterns were similar during 3 consecutive years at Mona Island in Puerto Rico and for the geographically isolated sites of Mona Island and Riley's Hump off Florida. At Bajo de Sico in Puerto Rico, courtship activity was lower than that at the other sites but reflected the same general patterns in 2014. For all 3 sites, spawning aggregations were found less than 150 m from a promontory at depths between 25 and 35 m near deep water (>100 m). [ABSTRACT FROM AUTHOR]

The Atlantic silverside (Menidia menidia) is extremely abundant in estuaries in eastern North America, is a significant component of food webs, and is the subject of many laboratory studies; however, the ecology of the larvae of this species in estuaries is poorly known. Using 4 simple collecting gears, we sampled Atlantic silverside larvae in 2 estuaries in Rhode Island that differ in anthropogenic inputs, Pettaquamscutt River estuary and Point Judith Pond, to assess the distribution and abundance of larvae of this species. These larvae occur predominantly in waters less than 1 m deep and are patchily distributed. Larvae collected at depths of 0.2-0.6 m were significantly shorter than those collected at depths of 0.6-0.8 m--a difference in mean total length of ~2 mm. We also compared diets and growth rates of larvae in the 2 estuaries, using gut content analysis and otolith analysis, respectively. Copepod eggs made up 76% of the diet of larval Atlantic silverside in Pettaquamscutt River, whereas copepod nauplii made up 73% of their diet in Point Judith Pond. Growth rates of the larvae did not differ between estuaries. [ABSTRACT FROM AUTHOR]