The red snapper (Lutjanus campechanus) is an economically vital resource in the northern Gulf of America (GOA), and its management is a topic of considerable debate in the region. To better inform stock assessments and fishery management, spatiotemporal trends in the following measures for adults were examined: distribution, abundance (catch per unit of effort [CPUE]), size (fork length [FL]), age, and sex ratio. Data were drawn from a spatially comprehensive, fishery-independent bottom longline survey conducted from 2001 through 2023. Statistical models were used to evaluate changes across 2 regions (eastern and western GOA, separated at the longitude 88°W) and 4 time blocks. No significant distribution shifts within either region were found. Mean CPUE was consistently higher in the western GOA, where it increased eightfold between 2001–2004 and 2019–2023, and CPUE in the eastern GOA remained consistently low. Mean FL was higher in the west region, except during the final time block (2019–2023), when it became equivalent across both regions. The average age of fish in the west region was approximately 12 years (standard error of the mean [SE] 0.34), compared to 7 years (SE 0.36) in the east region. No sex ratio differences were observed between regions or over time. Relationships between CPUE and habitat variables (depth, temperature, and salinity) also remained consistent.
An illustrated description of the juvenile stage of the largetooth swallower (Kali macrodon) from the eastern North Atlantic Ocean is given. The characteristics on which this identification is based and the problems of identifying larvae by using DNA barcoding are discussed. The specimens are compared with the previously described juveniles of the shortnose swallower (K. indica), the curvejaw swallower (K. kerberti), Kali spp., and Gargaropteron pterodactylops, previously thought to be a synonym for K. macrodon. Gargaropteron pterodactylops apparently belongs not to K. macrodon but to the darkmouth swallower (K. parri). The main differences between the juveniles of K. macrodon and juveniles of other species in the genus are in the pigmentation patterns. We also present data supporting the use of Kali caribbaea as the senior synonym of Kali colubrina and include a phylogenetic tree of the Kali species based on cytochrome c oxidase subunit 1 sequences.
this study, we examined how anglers in South Florida respond to changes in trip costs and regulations of fishing for dolphinfish (Cory-phaena hippurus). Using data from a survey of private boat anglers conducted in 2024, we estimated a model predicting changes in the frequency of fishing trips from cost variations and bag limit adjustments. We found that the average economic value of a trip on which dolphinfish are targeted, or how much an angler is willing to pay for such a trip, is approximately $200, with anglers sensitive to both cost and regulatory changes. Trip demand is elastic-a 1% cost increase reduces the number of trips by about 1.15%. Bag limit responses vary by baseline: increasing the current 10-fish limit by 1 fish raises the number of trips by roughly 1%, and adding a fish when the limit is 4 fish increases the number of trips by around 3%. Marginal willingness to pay similarly depends on the starting point, ranging from $2 for the 11th fish to $10 for the 1st fish, demonstrating diminishing returns as limits increase. These results provide valuable information for predicting rec reational fishing effort and economic effects under potential management scenarios, including seasonal closures and bag limit modifications. There fore, this research supports fishery managers in balancing conservation objectives with socioeconomic considerations in the dolphinfish fishery in the southeastern United States.--
The silky shark (Carcharhinus falciformis) is a key component of elasmobranch catches in fisheries in the eastern Pacific Ocean, and it is the main target species in the central Mexican Pacific. In this study, we developed the first index of standardized catch per unit of effort (CPUE) for the commercial longline fishery operating in the central Mexican Pacific, an index based on data collected by observers on board vessels during 2003–2017. Standardized CPUE trends were derived by using mixed models incorporating fishing effort (hooks), temporal (year and quarter), and spatial predictors affecting catchability, with sea-surface temperature included as a density covariate; fishing trip (or the ID assigned to each trip, hereafter referred to as TripID) was included as a random intercept to account for within-trip dependence. The interannual variability of standardized CPUE is marked, with values increasing during 2012–2015 after a period of decline, followed by a moderate decrease through 2017; nominal CPUE has a similar pattern. Spatial predictions indicate that variability was driven mainly by changes in intensity, with moderate expansions or contractions within a broadly stable central–southern distribution. These results provide a baseline for monitoring population trends and highlight the value of integrating spatiotemporal and environmental predictors into CPUE standardization for this species. Continued data collection by observers will strengthen abundance indicators and support science-based management of silky sharks across the eastern Pacific Ocean.
Atlantic sturgeon (Acip enser oxyrinchus) received protections under the U.S. Endangered Species Act in 2012. The commercial fishery for Atlantic sturgeon was closed in 1998, and no estimates of total abundance of any U.S. populations have been produced since an analysis in 2007 of commercial harvest from 1985 through 1995. In this study, we assessed the abundance of York River adult Atlantic sturgeon by using the POPAN model, which relies on knowledge of annual survival, capture probability, and annual recruitment to the adult popula tion. From 2013 through 2023, we cap tured 436 individual Atlantic sturgeon 985 times with 313 events in which a fish was recaptured in a year different from the year it was first caught. Results from the POPAN model indicate that, during that period, 738 individuals (95% confidence limits [95% CLs]: 651-839 individuals) were available for capture. Further, total annual abundance estimates ranged from 204 individuals (95% CLs: 177-238 individuals) in 2013 to 657 individuals (95% CLs: 570-756 individuals) in 2023. Estimates of male and female recruit-ment to the adult life stage from the best-fitting model are 8.0% and 5.7% per year for those 11 years, amounting to average population growth of 12.7% per year. Although evidence of population growth is encouraging, at these levels of abundance, this population of Atlantic sturgeon remains at risk of demographic extirpation.
recent bycatch mitigation efforts to reduce fishery effects on populations of pelagic shark species, commercial fisheries continue to affect this vulnerable group. The widespread deployment of natural baits coupled with the sharp olfaction of elasmobranchs continues to drive longline bycatch, regardless of policies prohibiting retention. We explored the use of artificial baits for catching tuna species and minimizing shark bycatch in a tuna longline fishery off Hawaii. Assessments of catch performance were conducted around the Cross Sea-mount from February 2022 through April 2023 to test hypotheses that artificial baits can be used to 1) effectively catch tuna species and 2) reduce shark bycatch compared to that with natural baits. During experimental deployments, we alternated using baskets of illuminated artificial baits and those of natural sardine baits, following initial tests with different artificial bait sizes, colors, and illumination sources. Preliminary catch data from 29 sets deployed during Phase 1 trials and 45 sets conducted in Phase 2 trials indicate that artificial baits were highly selective, with catch of only marketable species and no elasmobranchs. Although initial tuna catch rates were lower with artificial baits than with natural baits, preliminary findings indicate that further refinement of artificial bait configurations and light sources may provide a practical option to avoid shark interactions during longline operations.
The North American river otter (Lontra canadensis) is mainly an opportunistic forager inhabiting coastal areas throughout the Pacific Northwest of the United States. Using parts from scat samples, collected along the estuaries of the Wa'atch and Tsoo-Yess Rivers in Washington State during the summer of 2018 and the spring and summer of 2019, we analyzed the diet of this species in estuaries of Makah Bay. We documented one of the most diverse diets of North American river otters in Washington: 45 prey species were identified among 17 fish families and 10 decapod taxa. Pacific staghorn sculpin (Leptocottus armatus), saddle-back gunnel (Pholis sp. cf. ornata), and starry flounder (Platichthys stellatus) were the 3 most prevalent species in the diet of North American river otters (>47% frequency of occurrence for each of the 3 species). We suggest that the variation among prey species in the diet was driven primarily by habitat, followed by prey abundance and availability. Limited incidences of subtidal prey species, instances of high-volume predation on dense aggregations of fish prey, and the presence of commercially important species open interesting insights into foraging behavior or prey species distribution. Our study resulted in the first description of the diet of North American river otters in the area.
endangered small tooth sawfish (Pristis pectinata) has been protected under the U.S. Endangered Species Act since 2003. Once common throughout the Indian River Lagoon, in Florida, the species was extirpated from this estuarine system by the 1970s because of bycatch mortality. Hotline reports of small juve niles in this estuarine system were rare until 2015, when an increase in reports began and peaked between 2020 and 2023, prompting research to assess habitat use. Seven small juveniles were acoustically tagged and monitored for 1-2 years. Individuals spent up to 87% of the days on which they were detected in a 0.4-km2 area of the South Fork of-- the Saint Lucie River, a major tributary to the Indian River Lagoon. In the South Fork, juveniles were most fre quently detected in the following water conditions: temperatures of 24 degrees C-29 degrees C, salinities of 15-30, dissolved oxygen levels of 5-7 mg/L, and freshwater inflows of 50-150 m3/s. These findings indicate that the Indian River Lagoon is a nursery again. Identifying high-use areas within the broader nursery, such as the upper Saint Lucie River, is an important step toward safeguarding key habitats, and such habitat protection is essential for promoting reestab lishment of this species into historical parts of its range.--
initial life stages of the southern black drum (Pogonias courbina) have not been described. We describe changes that occurred up to 27 d post-hatch (dph) in larvae from spawning broodstock held in the laboratory and previously captured in the wild. Meristic and morphometric measurements indicate that the early development of P. courbina is similar to that of other species of Sciaenidae. Eggs had a homogenous yolk (average diameter of eggs: 1.01 mm [standard deviation (SD) 0.051) and one oil globule (average area of globules: 0.11 mm2 [SD 0.061). At hatching, mean standard length (SL) of larvae was 1.96 mm, and the yolk is absorbed 2 dph when larvae reach 2.85 mm SL. The oil globule is fully consumed 5-6 dph. The caudal fin is the first to appear (at 7 dph) and ossifies 10 d thereafter. Notochord flexion begins at 8 dph. Transformation ends 20 dph, and pigment expansion results in 4 distinct line patterns by 27 dph. The growth of larvae of southern black drum was linear, with an average rate of 0.46 mm SL/d. The changes in larval development observed in this study fill the gap in knowledge regarding the early life stages of this species.
smalltooth sawfish (Pristis pectinata) was listed as endangered under the U.S. Endangered Species Act in 2003 because of a precipitous population decline primarily due to being taken as bycatch. The anatomy and internal morphology of this species and other sawfishes (Pristidae) are poorly documented but are important to understand from conservation and ecological perspectives. For example, entanglement in marine debris is frequently reported for this species and damages the cranial musculature, impeding feeding and ventilation through spiracles and gills. With improved understanding of its myology, we can identify how marine debris can damage the cranial musculature of individuals. We identified the cranial musculature of the smalltooth sawfish by examining freshly dead juvenile and adult specimens, and we describe it herein. The musculature differed little from that of guitarfish and wedgefish species; however, the defining muscular feature is the large, paired antorbitopectoralis muscles that anchor the lateral chondrocranium of pristids, and by proxy, their toothed rostrum, to the pectoral musculoskeletal system. On the basis of attachment characteristics and proximity to other muscles, we hypothesize that the large antorbitopectoralis muscles are used to actuate headshaking behaviors, such as those related to feeding, defense, and courtship. Finally, entanglement in marine debris has resulted in damage to 17 of the 24 cranial muscles associated with biological functions, including feeding and ventilation, damage that negatively affects fitness and may affect survivorship.
axillary seabream (Pagellus acarne) is of economic importance for recreational and commercial fisheries in the Atlantic Ocean and Mediterranean Sea. A decline in total landings of this species off the coast of Portugal has been observed and raised some concern. A total of 520 individuals, between 7.8 and 34.2 cm in total length (TL), were collected monthly from September 2020 through August 2022 from commercial landings of fishing vessels operating off mainland Portugal. Age varied between 0 years (7.8 cm TL) and 15 years (34.2 cm TL), and the hyperbolic modification of the von Bertalanffy growth curve has the best fit to the data with a change in growth occurring at 3 years, which corresponds to the average age for sexual maturity in the species. The axillary seabream proved to be a protandric hermaphrodite, with males prevailing until a size of 28.0 cm TL and females prevailing at sizes between 28.0 and 34.0 cm TL. The spawning season occurred from April through October with a spawning peak between June and August.
Ovaries from female shortspine thornyhead (Sebastolobus alascanus) collected in the Aleutian Islands and Gulf of Alaska from 2014 through 2016 were used to investigate aspects of the reproductive biology of this species. Although this species is abundant in both geographical areas, published data on its reproduction remain limited. Ovaries were examined histologically to assess their development and to determine length and age at maturity. The seasonality of ovarian development was similar between geographical areas, with females spawning in May and June. Mature ovaries in early developing phases were observed in October. For females, length at 50% maturity was 23.0 cm in fork length (FL) (95% confidence interval [CI]: 22.3–23.8 cm FL), and age at 50% maturity was 12.8 years (95% CI: 12.00–13.51 years), with all of them maturing at ages between 11 and 14 years. Precision in age estimates between readers was acceptable (coefficient of variation=9.45; average percent error=6.69; percent agreement=25.9%), compared with that in estimates for difficult-to-age rockfish species (Sebastes spp.). This study resulted in additional knowledge of the reproductive biology of the shortspine thornyhead and greater understanding of its life history for fisheries management. Larger sample sizes and greater spatiotemporal coverage for sampling of specimens for aging are necessary to further identify maturity of this species and differences between geographical areas.
Accurate estimates of age, somatic growth, maturity, and natural mortality are essential for effective conservation of endangered species. This study resulted in updated growth data and the first direct assessments of length at maturity and age at maturity for the endangered smalltooth sawfish (Pristis pectinata). A Bayesian approach using the von Bertalanffy growth function was used to combine vertebral band counts, mark-recapture data, and results from increment analysis to estimate somatic growth and to derive age at maturity and natural mortality rates. Smalltooth sawfish grow rapidly in their first 3 years, reaching 235 cm stretch total length (STL), 3.2 times their mean length at birth (73.7 cm STL), before growth slows. Asymptotic length was 446 cm STL for males and 484 cm STL for females, with a Brody growth coefficient of 0.178 year−1 for males and 0.170 year−1 for females. We directly estimated median age at maturity as 6.9 years for males and 7.9 years for females, similar to previous indirect assessments. Constant natural mortality was estimated to be between 0.151 and 0.278 on the basis of life history surrogates. The oldest individual examined in this study was a 30.1-year-old female, confirming that the species exceeds 30 years in the wild. These results are vital for refining population recovery models, and they underscore the need for ongoing monitoring and data collection to support long-term recovery efforts.
The aim of stock assessment modeling is to evaluate current and future stock statuses under various management scenarios. For these assessments, particularly short-term projections, researchers rely heavily on recruitment estimates. However, accurately estimating recruitment levels, especially for the most recent years, is challenging because reliable information is limited. Indices of relative recruitment can provide valuable insights for stock assessment models in such cases. Herein, a method for assessing the reliability of a recruitment index with diagnostic and randomization tests in an age-structured production model (ASPM) is presented. The proposed method can be used to evaluate whether the process variability implied by a recruitment index for the spawner–recruit relationship enhances the connection between observed catches, indices of adult abundance, and the assessment model’s production function. We applied this approach to Pacific bluefin tuna (Thunnus orientalis) as an illustrative example. Results indicate that the ASPM, with recruitment fluctuations matching the recruitment index for the Sea of Japan (ASPM-R-FIX), improved the fits to recent adult abundance indices over those of the standard ASPM models. The results from statistical analysis further provide strong evidence that extreme recruitment fluctuations in the ASPM-R-FIX enhanced predictions for recent indices for adults. This analysis revealed a strong link between recruitment variability and adult abundance, highlighting the importance of adding a consistent recruitment index to an assessment model to improve management decisions.
