Abstract In the northwestern Atlantic the genusLagocephalusis represented by 2 species:Lagocephalus lagocephalus, with an oceanic distribution, andLagocephalus laevigatus, of coastal habits. In the present work the first records of the species in the Gulf of Mexico and Caribbean waters off Mexico are presented, with 18 adult and juvenile specimens being captured. The adults reached sizes of 360-484 mm standard length (SL) and weighed between 845 and 1,900 g, and the sizes of the juveniles ranged between 24 and 30 mm SL, with weight ranging between 1 and 10 g. Specimens were caught using a mid-water net (NMWT 25/25), a surface longline, and a bottom longline in neritic and oceanic waters of the exclusive economic zone in the Gulf of Mexico and the Caribbean Sea off Mexico, at depths ranging from 30 to 312 m. The presence ofL. lagocephalusmay be associated with the climatic conditions of the nortes season, when strong winds blow towards the coastal region, and with the reproductive phase of the species.

Resumen En el Atlántico noroccidental, el géneroLagocephalusestá representado por 2 especies:Lagocephalus lagocephalus, con distribución oceánica, yLagocephalus laevigatus, de hábitos costeros. En el presente trabajo se documentan los primeros registros deL. lagocephalusen el golfo de México y aguas del Caribe frente a México, con la captura de 18 ejemplares adultos y juveniles. Los adultos alcanzaron tallas de 360-484 mm de longitud estándar (LE) y peso de 845-1,900 g, y las tallas de los juveniles fueron de entre 24 y 30 mm LE, con un peso de 1 a 10 g. Los ejemplares fueron capturados con red de media agua tipo NMWT 25/25, palangre de superficie y palangre de fondo en aguas neríticas y oceánicas de la zona económica exclusiva del golfo de México, a profundidades desde 30 m hasta 312 m. Su captura puede estar asociada con las condiciones climáticas de la época de nortes, que ocasionan vientos fuertes con dirección a la región costera, y con la fase reproductiva de la especie.

Abstract Introduction: Until today, the fishing effort by foreign fleets in the Costa Rican Pacific has not been analyzed. Objective: To determine the spatial distribution of the fishing effort of those fleets, variables that shape that distribution, and if they interact with management figures and highly fragile ecosystems. Methods: Using fishing effort data from 2012 to 2020, obtained from Global Fishing Watch, an Index of Fishing Effort (IEP) was calculated to apply geospatial and multivariate statistics, as well as multiple regression models. A grid with 55 905 cells of 0.10 degrees was used to apply Hot Spot Analysis, and another grid with 24 176 cell-year-month analysis units of 0.25 degrees was used to apply a Linear Regression Model. Results: The data reveals the fishing activity of international fleets associated with four types of fishing gear, and a wide coverage of a high IEP by two fleets throughout the nine years analyzed. The IEP is primarily associated with location and varies by month and year. There is also relative evidence that its influenced by the concentration of oxygen and nitrates. Conclusions: International fleets come into direct conflict with officially defined zones for national fleets and disrespect protected oceanic areas and a declared non-fishing zone to protect marine resources in the Costa Rican Pacific. Their activities in the Dome may affect a national yellowfin tuna fishery.

Abstract Atlantic pearl oyster Pinctada imbricata is a bivalve with high potential for cultivation in tropical and subtropical environments. In this study, P. imbricata energetic metabolism was analyzed throughout a culture cycle at Gulf of Cariaco, Venezuela. Juvenile individuals (shell length 27.40 ± 2.70 mm) were cultured in a long line at 3 m depth between May-2012 and January-2013. Monthly data of biometric measurements, Fulton index (K) and protein, carbohydrate, and lipid content of the adductor muscle, digestive gland, and mantle were estimated, and were related with environmental variables: temperature, chlorophyll a (Ch a), total particulate matter (TPM), particulate inorganic matter (PIM), particulate organic matter (POM) and upwelling index (UI). Shell length increased steadily reaching 46.23 ± 3.79 mm on the 8th month of culture, while average soft tissue weight increased associated to food availability. Biometric data and biochemical substrates from the muscle, digestive gland and mantle presented significant differences among months. Principal Component Analysis (PCA) showed positive relationships between carbohydrate content and temperature; mantle and digestive gland protein content with TPM, PIM, POM, UI; lipid and protein in muscle with K. Energy allocation was associated with environmental factors, mainly through high food availability given the seasonal upwelling pulses in the area.

Resumen La ostra perlera del Atlántico Pinctada imbricata es un bivalvo con gran potencial de cultivo en ambientes tropicales y subtropicales. En este estudio el metabolismo energético de la ostra perla Pinctada imbricata fue analizado durante un ciclo de cultivo en el Golfo de Cariaco, Venezuela. El cultivo se realizó usando individuos juveniles con una longitud total de la concha de 27,40 ± 2,70 mm. Los ejemplares se cultivaron a 3 m de profundidad en un long-line, entre mayo 2012 y enero 2013. Mensualmente se obtuvieron los datos biométricos, el índice metabólico de Fulton (K), el contenido de proteína, carbohidrato y lípido del músculo aductor, la glándula digestiva y el manto los cuales se relacionaron con las variables ambientales de temperatura, clorofila a, material total en suspensión (TPM), materia inorgánica particulada (PIM), materia orgánica particulada (POM), y el índice de surgencia (UI). La longitud de la concha incrementó progresivamente hasta alcanzar 46,23 ± 3,79 mm en el octavo mes del cultivo, mientras que el incremento del peso promedio de los tejidos blandos estuvo asociado a la disponibilidad de alimento. Los promedios de las variables biométricas y bioquímicas del músculo, glándula digestiva y manto presentaron diferencias significativas entre meses. El análisis de componentes principales (PCA) indicó que hubo relaciones significativas del contenido de carbohidratos con la temperatura; las proteínas del manto y la glándula digestiva con TPM, PIM, POM y UI: del contenido de lípido y la proteína del músculo con K. Los compartimientos de energía se asociaron a factores ambientales, principalmente a la alta disponibilidad de alimento debido a los procesos de surgencia estacional de la localidad.

Abstract Studies relating the populational structure of target species to operational and environmental variables contribute directly to the management of the fisheries in these resources. Therefore, this study aimed to provide data on fishing and ecology of the swordfish ( Xiphias gladius) caught by the Brazilian longline fleet operating in the western Atlantic between 2010 and 2016. Generalized additive mixed models were used to evaluate the relationship between explanatory variables and responses based on Catch Per Unit of Effort (CPUE) data. Results show that the Brazilian longline fleet catches the swordfish mostly between latitudes of 5°N to 30°S and longitudes of 20° to 50°W and that the swordfish prefers temperatures under 25°C at depths below 60 meters. The species showed a tendency toward intermediate light intensity, predominating in the crescent moon phase, and a preference for areas with low chlorophyll concentrations. Our findings on operational and environmental interactions with swordfish CPUE suggest areas and times that can be used by fishing fleets and government institutions as a starting point for swordfish management strategies. resources Therefore gladius 201 2016 (CPUE 5N N 5 30S S 30 20 50W W 50 25C C 25 6 meters intensity phase concentrations strategies 3 2

Abstract This study investigated injuries sustained by Pimelodus maculatus caused by transient operating conditions in a Brazilian hydroelectric power plant. Fish (n = 43) that inhabited the tailrace and appeared on the water surface after changes in the operating conditions were evaluated (IF). Additionally, fish (n = 10) captured using longline in the vicinity of the tailrace were used for comparisons (NF). Blood samples were evaluated for cortisol, glucose, and lactate concentrations. Tissue samples (gill, liver, brain, and muscle) were analyzed for oxidative stress biomarkers (TBARS, protein carbonyl content, and catalase activity) and histology (gill, liver, and spleen). The most prominent findings in IF were barotraumas with intra-abdominal hemorrhage and swim bladder rupture. Cortisol and glucose concentrations were lower for IF when compared to NF. IF also suffered from oxidative stress, as indicated by increased TBARS in the liver and brain, as well as increased protein carbonyl content in the gills and liver. The main histological alterations induced by the adverse conditions were circulatory disorders, such as telangiectasia and gill aneurysm, hepatic congested veins, and hemorrhage in the liver and spleen. The abrupt drop of pressure resulting from changes in the operating conditions of the turbines caused barotraumas and oxidative stress, which were the leading causes of fish mortality plant n 43 IF. . (IF) Additionally 10 NF (NF) cortisol gill, (gill brain muscle TBARS, (TBARS activity spleen spleen) intraabdominal intra abdominal rupture disorders aneurysm veins 4 (IF 1 (NF

Resumo Este estudo investigou os efeitos induzidos por condições transitórias de operação em uma usina hidrelétrica brasileira em Pimelodus maculatus. Peixes (n = 43) no canal de fuga que apareceram na superfície da água após mudanças nas condições operacionais foram avaliados. Adicionalmente, peixes (n = 10) capturados a jusante da barragem com espinhel foram utilizados para comparações (NF). Amostras de sangue foram avaliadas para as concentrações de cortisol, glicose e lactato. Amostras de tecidos (brânquia, fígado, cérebro e músculo) foram analisadas para biomarcadores de estresse oxidativo (TBARS, conteúdo de proteína carbonil e atividade da catalase) e histologia (brânquia, fígado e baço). Os achados mais proeminentes dos peixes afetados (IF) foram barotraumas com hemorragia intra-abdominal e ruptura da bexiga natatória. As concentrações de cortisol e glicose foram menores para IF quando comparadas aos NF. IF também sofreram estresse oxidativo representado pelo aumento de TBARS no fígado e cérebro, e aumento do conteúdo das proteínas carboniladas nas brânquias e fígado. As principais alterações histológicas induzidas pelas condições adversas foram distúrbios circulatórios, como telangiectasia e aneurisma nas brânquias, congestão das veias hepáticas, e hemorragia no fígado e baço. A queda abrupta da pressão resultante de mudanças nas condições operacionais das turbinas causou barotrauma e estresse oxidativo, que foram as principais causas da mortalidade dos peixes. maculatus n 43 avaliados Adicionalmente 10 NF . (NF) lactato brânquia, brânquia (brânquia músculo TBARS, (TBARS catalase baço baço) (IF intraabdominal intra abdominal natatória circulatórios hepáticas 4 1 (NF

Resumen. La pesquería de pequeña escala de atún que opera con palangre en la costa de Nayarit comenzó recientemente en 2013. Ofrecemos la primera información detallada sobre algunos parámetros biológicos del atún aleta amarrilla (AAA) en Nayarit (México). Tomamos 584 muestras de AAA (captura de 25.5 t). Ajustamos la relación longitud-peso, utilizamos la prueba de t para determinar el tipo de crecimiento y estimamos la curva de selectividad. La longitud total varió de 73.0 a 228.0 cm, con una media de 153.0 ± 23.5 cm (media ± desviación estándar). El peso varió de 5.8 a 128.0 kg, con una media de 43.7 ± 19.4 kg. Los resultados del ajuste de longitud-peso y la prueba de t sugirieron que el crecimiento es alométrico negativo. Los resultados del ajuste de la selectividad sugirieron que la selectividad sigue un patrón asintótico. Nuestros resultados representan el primer paso en la recopilación de información para establecer programas de investigación y monitoreo de AAA en el océano Pacífico frente a México. La información proporcionada en este estudio podría ayudar a desarrollar las regulaciones para asegurar una pesquería bien administrada y la explotación sostenible del AAA en Nayarit.

Abstract. The small-scale tuna longline fishery operating on the coast of Nayarit started recently in 2013. We provide the first detailed report on some biological parameters for the yellowfin tuna (YFT) in Nayarit (Mexico). We sampled 584 YFT, representing a catch of 25.5 t. We fit the length-weight relationship, used the t-test to determine the type of growth, and estimated the selectivity curve. The total length data varied from 73.0 to 228.0 cm, with a mean of 153.0 ± 23.5 cm (mean ± SD). Weight ranged from 5.8 to 128.0 kg, with a mean of 43.7 ± 19.4 kg. Length-weight fitting results and the t-test suggested negative allometric growth. Selectivity fitting results suggested that selectivity follows an asymptotic pattern. Our results represent the first step into gathering information to establish research and monitoring programs for the YFT on the Pacific coast of Mexico. The information provided in this study could help develop proper regulations to assure a well-managed fishery and the sustainable exploitation of YFT in Nayarit.

ABSTRACT There are very little data on Central America and the Western Caribbean elasmobranch populations. Here we present the first results of standardized fisheries-independent monitoring of sharks and rays in Panama’s Bocas del Toro Archipelago over four consecutive years. Using baited remote underwater videos (BRUVs), underwater visual census (UVC), and scientific longline, we provide baseline data on the composition, relative abundance, distribution, and demographics of seven shark species and six rays observed during the study. Observations differed among methods and habitats, with BRUVs (n = 148) more effective for assessing shark diversity and abundance and UVC (n = 108) more effective for assessing ray abundance. Nurse sharks (Ginglymostoma cirratum) and southern stingrays (Hypanus americanus) were the most commonly observed species overall (frequency of occurrence = 30.4 and 18.9%, respectively). Depth, temperature, and protected area status significantly affected the relative abundance of sharks and rays based on UVC and BRUV data. The use of scientific longlines (n = 55) highlighted the lagoon habitat as a potential nursery site for blacktip sharks (Carcharhinus limbatus), with juvenile (average total length = 113 cm) individuals representing 58% of longline captures. The results provide a current baseline for elasmobranch communities that can further aid in the conservation and management of these species nationally and regionally.

ABSTRACT Background: Pontinus rathbuni has a distribution from Virginia to Brazil, USA, including the north of The Gulf of Mexico, nevertheless, there was not evidence of its presence in the southern part of these sea. Goals: The objective of this work is to report a new record in the southwestern of The Gulf of Mexico, including the larger known record of its size. Methods: Five specimens were captured by deep longline (between 160 to 300 m of depth), in the south coast of Veracruz, and they were preserved in a scientific collection. Results: The specimen of P. rathbuni were adults between 178 to 235 mm of standard length and around of 145 - 450 g of weight. They were recognized by have 17 rays on pectoral fin, the third dorsal spine is not elongated and there is not their development of the ventral process of the hypohyal. Conclusions: This record has expanded its distribution in 1,065 km toward the south of The Gulf of Mexico and this is the first record corroborated to Mexico. Also, there is a remarkable corporal size for this species.

RESUMEN Antecedentes: Pontinus rathbuni tiene una distribución que va de Virginia, EE.UU. a Brasil, incluyendo la parte norte del Golfo de México, sin embargo, no se tenía evidencia de su presencia en la parte sur de este mar. Objetivo: El objetivo de este trabajo es reportar un nuevo registro en el suroeste del Golfo de México, incluyendo el máximo registro conocido de su talla. Métodos: Cinco ejemplares fueron capturados en la costa del sur de Veracruz por medio de palangre de profundidad (entre los 160 a 300 m de profundidad), y se preservaron en una colección científica. Resultados: Los ejemplares de P. rathbuni, eran adultos, entre los 178 - 235 mm de longitud patrón y 145 - 450 g de peso, se reconocieron por tener 17 radios en la aleta pectoral, la tercera espina dorsal no es alargada ni hay desarrollo del proceso ventral del hipohial. Conclusiones: Este registro amplió su distribución en 1,065 km al sur del Golfo de México, es el primer registro corroborado para México, y se presenta una marca de talla corporal para la especie.

ABSTRACT Lightsticks baits are discharged into the ocean after their use in longline fishing. The traditional Brazilian community of Costa dos Coqueiros, Bahia, uses lightsticks as a medicine for rheumatism, vitiligo, and mycoses. It may affect marine life when its content leak into the ocean. This study assessed the toxicity identification and evaluation (TIE) of lightsticks constituents on marine mysids Promysis atlantica. The internal solution was dissolved in seawater with ethanol. The lethal concentration of the contaminant that causes mortality in 50% of the exposed population (LC50) after 3h was 0.001%, demonstrating that lightstick is exceptionally toxic because low concentrations cause mortality to mysids P. atlantica. Due to lightsticks’ high toxicity, the TIE baseline was 0.005% SSE (stock solution ethanol), and the selected endpoints were behavior and lethality. The sample submitted to aeration presented a significant reduction (P < 0.05) in toxicity (0.005% SSE) because the volatile compounds caused the toxic effect. The sodium thiosulfate treatment induced an insignificant decrease in toxicity. Thus, a new assay was conducted considering aeration and sodium thiosulfate. This combination reduced lightstick toxicity compared to the baseline lightstick, suggesting that volatile compounds and oxidants were responsible for toxicity; even in low concentrations, lightstick can promote significant behavior changes and deleterious effects. It is recommended to create new mechanisms to inspect fishing vessels, thus avoiding the improper disposal of attractors at sea and common garbage.

Abstract: The aim of this study was to determine the stock density effect on size and biomass on mussel Mytilus edulis platensis, at growth up phase ropes. These ropes were made using three initial stocking densities: 200, 300 and 400 mussels m-1 and hung on in a longline at Belvedere site on San Jorge gulf, Argentina. Stock density showed no influence on individual mussel biomass. Higher growth length was obtained at higher densities. According to these results, when the mussels are in the fattening or thinning out phase, the optimum stocking density would be 300 to 400 mussels m-1.

RESUMEN La pesquería artesanal avanzada de lanchas "pargueras" que opera en el área norte del mar Caribe de Colombia ha experimentado grandes dificultades relacionadas con el volumen de los desembarcos, que han llevado al colapso económico de la flota. La disminución de la abundancia de los recursos ícticos ha ocasionado la expansión del área de pesca, el aumento en la duración del viaje de pesca, la disminución de los ingresos y el incremento de los gastos de operación. Existen vacíos en el conocimiento de la distribución espacial actual e histórica del esfuerzo pesquero de la flota, que no permiten asociarlos a los cambios en las abundancias, la composición de las capturas y la disminución de tamaños de las especies capturadas. Mediante entrevistas a pescadores y con la ayuda del conocimiento ecológico tradicional, el conocimiento local y el uso de sistemas de información geográfica, se mapeó la distribución espacial del esfuerzo pesquero y su comportamiento desde los años 70 hasta la actualidad. Como principal resultado, se evidenció un aumento promedio de 134,5km en la distancia del viaje de pesca en casi 50 años y cambios en el área y profundidades de pesca, que variaron desde los 27,8 a 1117,8km2 y de los 93,8 a 41,1m, respectivamente. Los resultados obtenidos constituyen insumos valiosos para la implementación de estrategias de manejo, orientadas a asegurar la sostenibilidad ecológica y la viabilidad económica de esta importante pesquería.

ABSTRACT The advanced artisanal fishery of fishing boats called “pargueras” that operates in the northern area of the Colombian Caribbean has experienced great difficulties related to the volume of landings that have led to the economic collapse of the fleet. The decrease in the abundance of fish resources has caused an expansion of the fishing area, increased duration of the fishing trip, decreased incomes and the increase in operating expenses. Existing knowledge gaps with respect to current and historical spatial distribution of the fleet’s fishing effort prevent an association to changes in resource abundances, composition of catches and decreased species catch sizes. Through interviews with fishermen and based in traditional ecological knowledge, local knowledge and the use of geographic information systems, we mapped the spatial distribution of fishing effort and its inter-decadal behavior, from the 70s to present. The main result was a 134.5km increase in the distance of an average fishing trip in almost 50 years and changes in the surface area and fishing depths which varied from 27.8 to 1117.8km2 and 93.8 to 41.1m, respectively. The results obtained constitute valuable inputs for the implementation of management strategies aimed at ensuring the ecological sustainability and economic viability of this important fishery.

ABSTRACT The similarity theory was used to study the behavior of five anchoring and one “rezon” type deadweight designs, using scale models. The surface sediments extracted from Charagato Bay, Cubagua Island, were characterized to evaluate the efficiency of these models on these substrates. A test structure consisting of a tank with a mixture of sediment and seawater, and a metal trestle was used. Tension variables were considered, using a 6 mm PE end section. Weights were added at one of its ends which represented the longline system's resistance force and at the other the model's force in the eyebolt (Tc) representing the gripping force due to the interaction of the anchoring design with the substrate, and the static rupture tension (Tr) upon the weight (Pm) of each model, against different anchoring attack angles (θ), aspect ratios (AR) 1/2.5; 1/3.0; 1/3.5, and 1/4.0; sail attack angles (β) of 0, 10, and 20°, and the efficiency index (EI) of each model. The Kruskal-Wallis contrast was used to detect the possible differences against different anchoring attack angles, and, to locate the differences between them; box and mustache graphs were used. The most effective model on very fine sand-type sediment was the pyramidal with the claw-like frame, followed by the pyramidal with the shovel-like frame and the “rezon” type traditionally used on Margarita Island.

Abstract Support vector machine (SVM) is shown to have better performance in catch per unit of effort (CPUE) standardization than other methods. The SVM performance highly relates to its parameters selection and has not been discussed in CPUE standardization. Analyzing the influence of parameter selection on SVM performance for CPUE standardization could improve model construction and performance, and thus provide useful information to stock assessment and management. We applied SVM to standardize longline catch per unit fishing effort of fishery data for bigeye tuna (Thunnus obesus) in the tropical fishing area of Atlantic Ocean and evaluated three parameters optimization methods: a Grid Search method, and two improved hybrid algorithms, namely SVMs in combination with the particle swarm optimization (PSO-SVM), and genetic algorithms (GA-SVM), in order to increase the strength of SVM. The mean absolute error (MAE), mean square error (MSE), three types of correlation coefficients and the normalized mean square error (NMSE) were computed to compare the algorithm performances. The PSO-SVM and GA-SVM algorithms had particularly high performances of indicative values in the training data and dataset, and the performances of PSO-SVM were marginally better than GA-SVM. The Grid search algorithm had best performances of indicative values in testing data. In general, PSO was appropriate to optimize the SVM parameters in CPUE standardization. The standardized CPUE was unstable and low from 2007 to 2011, increased during 2011-2013, then decreased from 2015 to 2017. The abundance index was lower compared with before 2000 and showed a decreasing trend in recent years.

ABSTRACT. Elasmobranch species composition and spatiotemporal variability can often be characterized from landing surveys of local fisheries, with important management implications. In the present study, we describe the elasmobranch landing composition of 4 major artesanal fishing ports in northwestern Baja California, Mexico. Sampling was conducted opportunistically between 1995 and 2010 and included an effort of 684 fishing days. Species composition was gear-dependent and varied with the fishing area, with thresher sharks (Alopias vulpinus) and spiny dogfish (Squalus suckleyi) dominating the catches landed by coastal gill net fisheries, and blue sharks (Prionace glauca) and shortfin mako sharks (Isurus oxyrhinchus) dominating the catches landed by the offshore longline fishery. Size-structure analysis indicated that catches were composed primarily of juveniles for most species, although the catch of mature soupfin sharks (Galeorhinus galeus) increased in longline fisheries during the winter. The results indicate that minor regional differences in elasmobranch species composition occur along the Pacific coast of Baja California and are most likely related to regional oceanographic or habitat differences. The results of this study may form the basis for future efforts to monitor species composition changes over time, to more completely assess elasmobranch populations.

RESUMEN. La composición específica de elasmobranquios y su variabilidad espaciotemporal en una región marina frecuentemente pueden ser caracterizadas mediante el muestreo de los desembarques de la pesquería local, lo que puede tener implicaciones para su manejo. En el presente estudio, describimos la composición de los desembarques de elasmobranquios en 4 principales puertos pesqueros artesanales en el noroeste de Baja California, México. Los muestreos se realizaron de manera oportunista entre 1995 y 2010 e implicaron un esfuerzo de 684 días de pesca. La composición específica dependió del arte de pesca y de la zona de pesca, con el dominio del tiburón zorro común (Alopias vulpinus) y el tiburón perro espinoso (Squalus suckleyi) en las capturas con redes agalleras en la zona costera y el dominio del tiburón azul (Prionace glauca) y el tiburón mako (Isurus oxyrhinchus) en la captura con palangre en la zona oceánica. El análisis de la estructura de tallas indicó que la captura de la mayoría de las especies estuvo compuesta, principalmente, por organismos juveniles, aunque la captura de individuos maduros de tiburón sulfin (Galeorhinus galeus) mostró un incremento en la pesca con palangre durante el invierno. Los resultados indican que puede haber diferencias regionales menores en la composición específica de elasmobranquios a lo largo de la costa pacífica de Baja California, lo cual podría estar relacionado con diferencias oceanográficas o de hábitat entre regiones. El resultado de este estudio puede formar la base de futuros esfuerzos para monitorear los cambios en la composición de las especies a lo largo del tiempo y, así, evaluar de una manera más completa las poblaciones de elasmobranquios.

ABSTRACT Longlines bearing “hook timers” (HTs) and alternating circle (15/0 and 17/0) and “J” (10/0) hooks were employed off the coast of Brazil to measure differences in fishing mortality associated with hook type and on-hook time between capture and boarding. A total of 431 HTs were activated, revealing a clear pattern of the increased mortality rate of fishes associated with increased on-hook time. Swordfish had high mortality rates, unlike blue sharks, which had low mortality rates regardless of hook type and the location in which the hook was transfixed. The six species of tunas and billfishes examined in this study showed a strong association between hooking location and the animal's release condition, with reduced mortality associated with individuals hooked externally. Results suggest that knowledge of factors affecting the survival of pelagic fishes caught in longline fisheries may enable the development and adoption of fishing methods to reduce mortality of longline bycatch.