Abstract (Introduction): Bycatch and discards are a socio-environmental concern that threatens the sustainability of marine life and fishing grounds. Approaches to this problem have focused on biological and/or ecological aspects. We considered it necessary to explore the problem from the social dimension and for this purpose we explored social representations. (Objective): The aim of this study is to explore the social representations of bycatch and discards in a group of businessmen and workers in the capture stage of the Argentine industrial fishing activity. We ask how they evaluate bycatch and fishing discards, what are their causes and if they observe possible solutions. (Methodology): Within the framework of a project of the Federal Fishing Council, we conducted focus groups with businessmen, business chambers, SOMU workers and captains of the industrial fishing activity. (Results): The results of the focus groups conducted in 2021 reveal three main causes of this problem. First, the lack of reliable data on actual discard levels raises concerns about sustainability and overfishing. Second, the low utilization of selectivity devices is attributed to their operational inefficiency and possible labour barriers. Finally, economic and organizational pressures, such as company profitability and workers’ salaries, justify the discard of non-target species, exacerbating the problem. (Conclusions): The work contributes to an understanding of the main reasons for bycatch and discards, which is essential to advance solutions. We understand that solutions are not simple and involve a sincere debate among stakeholders.

Resumen (Introducción): Las capturas incidentales y los descartes pesqueros son una preocupación socioambiental que amenaza la sostenibilidad de la vida marina y de los caladeros. Los abordajes a esta problemática estuvieron centrados en aspectos biológicos y ecológicos. Consideramos necesario explorar la problemática desde la dimensión social y para ello, exploramos las representaciones sociales. (Objetivo): El objetivo de este estudio fue explorar las representaciones sobre capturas incidentales y descartes pesqueros en un grupo de empresarios y trabajadores de la etapa de captura de la actividad pesquera industrial argentina, específicamente, cómo evalúan este problema, sus causas y posibles soluciones. (Metodología): En el marco de un proyecto del Consejo Federal Pesquero, se realizaron grupos focales con seis cámaras empresariales y personal jerárquico de empresas asociadas, así como trabajadores del SOMU y capitanes que operan en alta mar. (Resultados): Los resultados de los grupos focales realizados en 2021 revelaron tres principales causas de dicha problemática. Primero, la falta de datos confiables sobre los niveles reales de descarte genera preocupaciones sobre la sostenibilidad y la sobreexplotación. Segundo, la escasa utilización de dispositivos de selectividad se atribuye a su ineficacia operativa y a posibles barreras laborales. Finalmente, las presiones económicas y organizacionales, como la rentabilidad de las empresas y los salarios de los trabajadores, justifican el descarte, exacerbando el problema. (Conclusiones): El trabajo aporta a un entendimiento sobre las razones de la captura incidental y los descarte, esencial para avanzar en soluciones. Entendemos que las soluciones no son simples e implican un sincero debate entre actores.

Chitosan (CS) blends with collagen (CL) and Aloe vera (AV) have gained significant attention in the biomedical field due to their biocompatibility, biodegradability, and potential for wound healing applications. In this study, we investigated the preparation and characterization of CS/CL and CS/AV blends using selective precipitation and co-precipitation techniques. The synthesis processes were analyzed for yield and 4-hydroxyproline content (in CS/CL blends). The materials were characterized using bromatological analyses, viscosity measurements, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). These eco-friendly methods effectively promoted interactions between the biopolymers, resulting in homogeneous blends with tunable properties. Besides, they are simple, fast, safe, and require minimal infrastructure. This study demonstrated that selective precipitation and co-precipitation are effective methods for producing chitosan/collagen and chitosan/Aloe vera blends. These methods foster interactions and miscibility between the biopolymers, as confirmed by FTIR, XRD, viscosity, and 4-Hy content analyses. They also align with green chemistry principles by avoiding organic solvents, reducing environmental risks, and minimizing waste. The high yields achieved, especially for CS/AV blends (exceeding 96%), make these materials compatible with lyophilization procedures. The absence of segregated phases after appropriate washing underscores their suitability for pharmaceutical formulations and other applications. CS (CS CL (CL AV (AV biocompatibility biodegradability applications CSCL CSAV coprecipitation co techniques 4hydroxyproline hydroxyproline 4 . blends) analyses measurements Fouriertransform Fourier transform FTIR , (FTIR) Xray X ray XRD (XRD) SEM. SEM (SEM) ecofriendly eco friendly biopolymers properties Besides simple fast safe infrastructure chitosancollagen chitosan chitosanAloe 4Hy Hy solvents risks waste achieved exceeding 96%, 96 96% 96%) procedures (FTIR (XRD (SEM 9

RESUMO: A regularização ambiental da piscicultura continental no Brasil está intimamente ligada à ocupação e uso do solo, as áreas utilizadas para a atividade estão em sua maioria inseridas em áreas de preservação permanente (APP), próximas a rios e nascentes. Esse cenário demonstra a relação entre a atividade e o cumprimento da lei, referente às questões florestais no país. Santa Catarina é um dos estados líderes na piscicultura e um dos primeiros a regulamentar o uso de áreas de preservação permanente (APPs). Assim, foi avaliada a viabilidade de uma proposta de compensação ambiental para regularizar o uso de APPs em Santa Catarina para a piscicultura. Os resultados mostraram que 74% das pisciculturas analisadas precisam regularizar a ocupação das estruturas de produção em APPs. Com relação ao índice proposto de compensação pelo uso em APP, o fator de compensação ambiental (FCA), por meio da avaliação dos mapas individuais e posterior avaliação integrada, todas as pisciculturas identificadas com passivos ambientais em ocupação apresentavam relações de 1:2 e 1:3, sendo este índice uma alternativa viável para a regularização ambiental da atividade. No entanto, propõe-se que o ECF seja aplicado a pequenas pisciculturas, de até quatro módulos fiscais e que tenham um perfil de ocupação mínima padrão em relação à área total da propriedade, conforme avaliado no presente estudo. RESUMO solo APP , (APP) nascentes lei país . (APPs) Assim 74 FCA, FCA (FCA) integrada 12 1 2 1: 13, 13 3, 3 1:3 entanto propõese propõe se propriedade estudo (APP (APPs 7 (FCA

ABSTRACT: The environmental regulation of continental fish farming in Brazil is closely linked to land occupation and use. Areas used for this activity are mostly located in permanent preservation areas (PPA), close to rivers and springs, demonstrating the necessity of regulating this activity for its compliance with public policy. Santa Catarina is a leading state in fish farming and one of the first to regulate the use of PPAs. The feasibility of a proposal for environmental compensation to regularize the use of PPAs in Santa Catarina for fish farming; was therefore, assessed. The results showed that 74% of the fish farms analyzed need to regularize the occupation of production structures in PPAs. Regarding the proposed index of compensation for use in PPAs, the environmental compensation factor (ECF), through evaluation of the individual maps and subsequent integrated evaluation, all the fish farms identified with environmental liabilities in occupation had ratios of 1:2 and 1:3, and this index is a viable alternative for environmental regularization of the activity. It was further proposed that ECF be applied to small fish farms of up to four fiscal modules and that they have a standard minimum occupancy profile in relation to the total area of the property, as assessed in the present study. ABSTRACT PPA, PPA , (PPA) springs policy therefore 74 ECF, (ECF) 12 1 2 1: 13, 13 3, 3 1:3 property study (PPA 7 (ECF

RESUMO: Este estudo explorou o uso exclusivo do ultrassom (US) para extrair proteínas das espinhas dorsais da carpa-capim (Ctenopharyngodon idella) em baixas temperaturas e examinou seu impacto na hidrofobicidade, solubilidade, perfil eletroforético e níveis de sulfidrilas. As espinhas dorsais foram tratadas com 35 e 130 kHz por 20, 30 e 40 minutos a 14 ºC, resultando em duas frações de proteínas: sólida (TPS) e líquida (TPL). O US aumentou o rendimento em comparação com a fração não sonificada. TPL (35 kHz) apresentou uma redução de 16% nos níveis totais e livres de sulfidrila e um aumento de 25% na hidrofobicidade. O US induziu alterações na conformação proteica e na intensidade das bandas, especialmente entre 25 e 100 kDa para TPL a 130 kHz e abaixo de 30 kDa para TPS a 35 kHz. Este estudo demonstrou a eficácia do US na extração e na modificação de algumas propriedades das proteínas de subprodutos de peixe, facilitando assim seu emprego no desenvolvimento de produtos alimentícios inovadores. RESUMO (US carpacapim carpa capim Ctenopharyngodon idella hidrofobicidade solubilidade sulfidrilas 3 13 20 4 1 ºC (TPS TPL. . (TPL) sonificada (3 16 bandas 2 10 peixe inovadores (TPL (

ABSTRACT: This study explored the use only of ultrasound (US) for extracting proteins from grass carp (Ctenopharyngodon idella) backbones at low temperature and examined its impact on hydrophobicity, solubility, electrophoretic profile, and sulfhydryl levels. Backbones were treated with 35 and 130 kHz for 20, 30, and 40 minutes at 14 ºC, resulting in two protein fractions: solid (TPS) and liquid (TPL). US increased yield compared to the non-sonicated fraction. TPL (35 kHz) exhibited a 16% reduction in total and free sulfhydryl levels and a 25% increase in hydrophobicity. US induced protein conformation and band intensity alterations, particularly between 25 to 100 kDa for TPL at 130 kHz and below 30 kDa for TPS at 35 kHz. This study demonstrated the efficacy of US for protein extraction from fish by-products and its capacity to modify protein characteristics, facilitating the development of innovative food products. ABSTRACT (US Ctenopharyngodon idella hydrophobicity solubility profile 3 13 20 4 1 ºC fractions (TPS TPL. . (TPL) nonsonicated non sonicated fraction (3 16 alterations 2 10 byproducts by products characteristics (TPL (

ABSTRACT The feeding habits of the bonito Euthynnus alletteratus and the albacore Thunnus alalunga were assessed by analyzing the contents of 85 stomachs (50 from bonito and 35 from albacore) collected between March 2018 and April 2019. A qualitative and quantitative analysis of the prey found in the stomach contents was conducted, as well as of the trophic spectrum between species and climatic seasons. Climatic information was obtained through satellite images, analyzing variables such as sea surface temperature, salinity, and winds. In terms of abundance, the most representative prey were the fish Sardinella aurita (42.48 %) and Teleostei remains (27.45 %) for E. alletteratus, and Megalopa larvae (56.89 %) and Teleostei remains (10.26 %) for T. alalunga. The relative importance index indicates that the main prey for E. alletteratus were Teleostei remains (IRI = 1460.65) and Sardinella aurita (IRI = 1179.70), while, for T. alalunga they were megalopa larvae (IRI = 1367.19) and Teleostei remains (IRI = 840.94). These large pelagic predators were classified as generalists, with a low prey diversity in their stomach content. No trophic overlap was observed between the two species.

RESUMEN Se evaluaron los hábitos alimentarios del bonito Euthynnus alletteratus y la albacora Thunnus alalunga a partir del análisis de los contenidos de 85 estómagos (50 de bonito y 35 de albacora) recolectados entre marzo de 2018 y abril de 2019. Se realizó un análisis cualitativo y cuantitativo de las presas encontradas en dichos estómagos, así como del espectro trófico entre especies y temporadas climáticas. La información climática se obtuvo a través de imágenes satelitales, analizando variables como la temperatura superficial del mar, la salinidad y los vientos. En términos de abundancia, las presas más representativas fueron el pez Sardinella aurita (42.48 %) y restos de Teleostei (27.45 %) para E. alletteratus, y larvas megalopa (56.89 %) y restos de Teleostei (10.26 %) para T. alalunga. El índice de importancia relativa indica, como presas principales, a restos de Teleostei (IRI = 1460.65) y Sardinella aurita (IRI = 1179.70) para E. alletteratus, y a larvas megalopa (IRI = 1367.19) y restos de Teleostei (IRI = 840.94) para T. alalunga. Estos grandes depredadores pelágicos fueron catalogados como generalistas, con baja diversidad de presas en el contenido estomacal, y no se observó solapamiento trófico entre las dos especies.

Resumen. La mojarra (Eucinostomus currani) es un recurso importante de subsistencia en mercados locales de Ecuador. Sin embargo, poco es sabido sobre la historia de vida temprana y la biología reproductiva de esta especie. En 2016 y 2017, se recolectaron larvas de E. currani en 3 playas arenosas en el Golfo de Guayaquil, Ecuador, y se identificaron usando códigos de barras de ADN. La longitud estándar de las larvas osciló entre 4.00 y 15.78 mm. También recolectamos otolitos para comprender mejor la historia de vida temprana de E. currani. Los otolitos se usaron para estimar la edad, la tasa de crecimiento de la población (±EE), las fechas de eclosión y la época reproductiva. En promedio, la edad de los peces fue de 16.5 ± 4.5 días, mientras que la tasa de crecimiento promedio fue de 0.70 ± 0.05 y 0.22 ± 0.16 mm por día en marzo y mayo, respectivamente. En el Golfo de Guayaquil, la mayoría de las fechas de eclosión y la actividad reproductiva presunta de E. currani ocurrió durante la época húmeda (diciembre-abril) cuando aguas más calidas prevalecieron. Hasta donde tenemos conocimiento, este es el primer estudio que estima las fechas de eclosión y la tasa de crecimiento larval para una especie de la familia Gerreidae en el Océano Pacífico.

Abstract. The flagfin mojarra (Eucinostomus currani) is an important subsistence fishery resource in local Ecuadorian markets; however, very little is known about the early life history and reproductive biology of this species. In 2016 and 2017, E. currani larvae were collected at 3 sandy beaches in the Gulf of Guayaquil, Ecuador, and identified using DNA barcoding. Standard lengths ranged from 4.00-15.78 mm. We also collected otoliths to better understand the early life history of E. currani. Otoliths were used to estimate the age, population growth rate (±SE), hatch dates, and reproductive period. On average, the fish were 16.5 ± 4.5 days old, while the average growth rate was 0.70 ± 0.05 and 0.22 ± 0.16 mm per day in March and May, respectively. In the Gulf of Guayaquil, most hatch dates and the presumed reproductive activity of E. currani occurred during the wet season (December-April) when warmer water prevailed. To our knowledge, this is the first study to estimate the hatch dates and larval growth rate for a species of the family Gerreidae in the Pacific Ocean.

Abstract Introduction: Semaprochilodus laticeps is a freshwater fish species native to the Orinoco Basin that is exploited in Colombia at two different stages of its life cycle: fry (for the ornamental trade) and adults (for the consumer market). This double exploitation of juveniles and adults raises concerns about the population stability of the species. Objective: To evaluate the sustainability of the exploitation of the species in these two life stages. Methods: 1 277 specimens of S. laticeps were sampled between June and December 2017. Population parameters were estimated from length-frequency data using ELEFAN 1 routine of the FISAT II package. Length at first maturity (Lm) and length at maximum yield (Lopt) were determined using the Froese and Binohlan equations. Virtual population analysis was performed based on Jones length cohort analysis. Results: Population parameters were as follows: K = 0.75, L∞ = 53.1 cm LE, Z = 2.92 yr-1, M = 1.24 yr-1 and F = 1.68. Lm was estimated to be 29.6 cm SL and Lopt at 33.4 cm SL. Of note, 96.3 % of the fish caught in the consumer fishery exceeded Lm and 80 % exceeded Lopt. The results of the virtual population analysis suggested that a very low proportion (0.85 %) of the population was caught as fry, possibly due to natural mortality. Conclusions: Based on the results, as no indicators of overexploitation were identified, it is recommended to continue with the dual use of S. laticeps. It is recommended to maintain the existing conservation measures, such as the closed season during the reproductive period, to ensure sustainable fishery exploitation. The results obtained can serve as a reference to analyze the situation of other species currently fished for both the ornamental (fry) and food (adult) markets.

Resumen Introducción: Semaprochilodus laticeps es una especie de pez de agua dulce originaria de la cuenca del Orinoco, explotada en Colombia en dos etapas distintas de su ciclo de vida: alevín (para el comercio ornamental) y adulto (para el mercado de consumo). Esta doble explotación de alevines y adultos genera preocupación sobre la estabilidad poblacional de la especie. Objetivo: Evaluar la sostenibilidad de la explotación de la especie en estas dos etapas de vida. Método: Entre junio y diciembre de 2017 se muestrearon 1 277 ejemplares de S. laticeps. Los parámetros poblacionales se estimaron utilizando datos de frecuencia de tallas con la rutina ELEFAN 1 del paquete FISAT II. La longitud de primera madurez (Lm) y la de máximo rendimiento (Lopt) se determinaron mediante ecuaciones de Froese y Binohlan. El análisis de la población virtual se realizó basándose en el análisis de cohorte de longitud de Jones. Resultados: Los parámetros poblacionales fueron los siguientes: K = 0.75, L∞ = 53.1 cm LE, Z = 2.92 año-1, M = 1.24 año-1 y F = 1.68. Lm se estimó en 29.6 cm SL y Lopt en 33.4 cm SL. En particular, el 96.3 % del pescado capturado en la pesquería de consumo superó Lm y el 80 % superó Lopt. El análisis de la población virtual sugirió que una fracción muy baja (0.85 %) de la población fue capturada como alevines, posiblemente atribuible a la mortalidad natural. Conclusiones: Con base en los hallazgos, al no identificarse indicadores de sobreexplotación, se recomienda continuar con el doble uso de S. laticeps. Se recomienda mantener las medidas de protección existentes, así como una veda durante el período reproductivo, para garantizar una explotación pesquera sostenible. Los resultados obtenidos pueden servir como referencia para analizar la situación de otras especies actualmente capturadas para el mercado tanto ornamental como de consumo.

Abstract Introduction: The Mar Muerto lagoon is an ecosystem characterized by high productivity upon which various inhabiting organisms depend. Additionally, it is a system susceptible to environmental impacts. Consequently, indices have been developed to determine the degree of disturbance caused by natural and/or anthropogenic factors. Objective: To assess the degree of disturbance in the Mar Muerto lagoon using a Biotic Integrity Index (BII) based on ichthyofauna. Methods: From December 2019 to March 2021, 12 sampling stations were established in the lagoon. The Biotic Integrity Index was developed by collecting data on hydrological variables (salinity, dissolved oxygen, pH, electrical conductivity, suspended solids, temperature, nitrites, nitrates, phosphates, and transparency) and classifying fish species based on their composition and richness. This was followed by a Water and Habitat Quality Index (WHQI) derived from the characterization and classification of sampling stations based on physicochemical variables. The correlation of the two indices allowed for the evaluation of the effectiveness of the BII. Results: 65 species were reported for the lagoon, with Lile gracilis, Oligoplites altus, Eucinostomus currani, and Gerres simillimus being the most frequently recorded. Only station 10 exhibited poor biotic integrity (BII = 26), while the rest displayed regular biotic integrity (BII = 30 - 44), with station nine presenting the highest calculated value (BII = 42). The assessment of the lagoon’s BII demonstrated an average biotic integrity considered “regular.” Conclusion: Through this study, the functionality of the modified BII for the Mar Muerto lagoon was verified, allowing for the evaluation of the present conservation status and comparison with previous studies.

Resumen Introducción: La laguna Mar Muerto es un ecosistema caracterizado por una gran productividad, de la cual dependen diversos organismos que la habitan; también es un sistema susceptible a impactos ambientales. Por lo anterior, se han desarrollado índices que permiten conocer el grado de alteración por causas naturales y/o antropogénicas. Objetivo: Evaluar el grado de perturbación de la laguna Mar Muerto, mediante un índice de integridad biótica (IBI) basado en la ictiofauna. Métodos: De diciembre 2019 a marzo 2021, se establecieron 12 estaciones de muestreo en la laguna. La elaboración del índice de integridad biótica fue a partir de la recopilación de datos de las variables hidrológicas (salinidad, NO2, NO3, PO4, pH, OD, T, CE, transparencia y SDT) y la clasificación de las especies ícticas según su composición y riqueza; seguido de un índice de calidad de agua y hábitat (ICAH), elaborado a partir de la caracterización y clasificación de las estaciones de muestreo en función de variables fisicoquímicas. La correlación de los dos índices permitió evaluar la efectividad del IBI. Resultados: 65 especies fueron reportadas para la laguna, de las cuales Lile gracilis, Oligoplites altus, Eucinostomus currani y Gerres simillimus se registraron con mayor frecuencia. Sólo la estación 10 presentó una integridad biótica pobre (IBI = 26), el resto presentó un IBI regular (IBI = 30 - 44), siendo la estación nueve la que presentó el valor máximo calculado (IBI = 42). La valoración del IBI de la laguna demostró que ésta presenta una integridad biótica promedio considerada “regular”. Conclusión: A través de este trabajo, se comprobó la funcionalidad del IBI modificado para la laguna Mar Muerto, permitiendo evaluar el grado de conservación presente y compararlo con trabajos previos.

Abstract Introduction: Coryphaena hippurus is a species of commercial interest with a high migratory capacity, a characteristic that places it in tropical and subtropical environments, preferring areas with a temperature range between 21 and 30 °C and salinity close to 31 ppt. Although the population trend of C. hippurus is stable, the fishing of this resource is increasing and occupies important positions in the economy of the Eastern Tropical Pacific coastal countries, which demonstrates the need to design and strengthen conservation strategies for the adequate use of this resource. Given its location in tropical and subtropical environments, its availability and distribution could be affected by climate change. Objective: To analyze the current and future potential distribution of C. hippurus under climate change scenarios. Methods: Ten algorithms were used to model the potential distribution and current habitat suitability index of C. hippurus as a function of sea surface temperature, current salinity and velocity, and these results were then projected under the most extreme climate change scenario. Results: There were good performances with all the algorithms used, but the model generated with BIOCLIM (AUC: 0.89) was chosen because it also solves the problem of spatial and temporal bias found in the records of the species. The region of greatest habitat suitability for C. hippurus matches the oceanic fronts of the Eastern Tropical Pacific. Under future conditions of extreme climate change, the species distribution pattern indicates a contraction, relocation, and expansion of habitat south of the equator. Conclusions: Under conditions of extreme climate change, the distribution model for C. hippurus suggests a process of topicalization of marine ecosystems in the Eastern Tropical Pacific by 2100.

Resumen Introducción: Coryphaena hippurus es una especie migratoria de interés comercial, que se encuentra en ambientes tropicales y subtropicales, prefiriendo zonas con un rango de temperatura entre 21 y 30 °C y salinidad cercana a 31 ppt. Aunque la tendencia poblacional del dorado es estable, la pesquería de este recurso está aumentando y ocupa importantes posiciones en la economía de países costeros del Pacífico Oriental Tropical, evidenciándose la necesidad de diseñar y fortalecer estrategias de conservación y mejorar el aprovechamiento de este recurso. Dada su ubicación en ambientes tropicales y subtropicales, la disponibilidad y distribución de este recurso podría verse afectado a futuro por el cambio climático. Objetivo: Analizar la distribución potencial actual y futura de C. hippurus bajo condiciones de cambio climático. Métodos: Se emplearon 10 algoritmos para modelar la distribución potencial e idoneidad de hábitat actual para C. hippurus a partir de la temperatura superficial del mar, la salinidad y velocidad de las corrientes, posteriormente se proyectaron estos resultados según el escenario de cambio climático más extremo. Resultados: Hubo buenos desempeños con todos los algoritmos empleados, pero se escogió el modelo generado con BIOCLIM (AUC: 0.89) pues además resuelve el inconveniente del sesgo espacial y temporal hallado en los registros de la especie. La región de mayor idoneidad de hábitat para C. hippurus coincide con los frentes oceánicos del Pacífico Oriental Tropical. En condiciones futuras de cambio climático extremo, el modelo de distribución de la especie indica una contracción, reubicación y expansión de hábitat hacia el sur de la línea ecuatorial. Conclusiones: En condiciones de cambio climático extremo, el modelo de distribución para C. hippurus sugiere un proceso de tropicalización de los ecosistemas marinos en el Pacífico Oriental Tropical para el año 2100.

Abstract Introduction: The pelagic sea snake Hydrophis platurus has the broadest distributional range of all the snakes and is the only sea snake of tropical waters off the west coast of the Americas. Within the variation in the color pattern of this species, completely yellow specimens were considered very rare or occasional. However, a yellow pattern dominates a population established in the interior of the Golfo Dulce in the Southern Pacific of Costa Rica. Objective: We studied the abundance, activity patterns, morphometry, and feeding behavior of the yellow H. platurus within the Golfo Dulce. Methods: Between February 2009 and July 2018, we conducted surveys for sea snakes from a boat within the perimeter of the Golfo Dulce. Results: Adults from the gulf population are smaller than the bicolor oceanic population, with females having larger bodies. Sea snakes within the gulf float and move with surface currents without being linked to drift lines and debris. These snakes are mainly found in clean, calm waters with little turbulence. They feed on a wide diversity of small fish, which they capture using passive stalking predatory behaviors floating on the surface. Prey are quickly captured and swallowed alive. This species has an almost total absence of predation, a pattern that extends to this yellow population. Conclusions: The characteristics of the gulf and the direction and strength of the surface currents at its entrance might restrict the transit of this yellow population to the outside and the entry of the bicolored snakes of the oceanic population. We do not consider making taxonomic changes in this Golfo Dulce population prudent. This yellow population is relatively common within the basin. However, the high tourist traffic and other activities are risk factors for its conservation. Protection policies must be created to preserve and protect this small population of yellow sea snakes unique within this species’ distribution range.

Resumen Introducción: La serpiente marina pelágica Hydrophis platurus tiene el rango de distribución más amplio de todas las serpientes y es la única serpiente marina de aguas tropicales del oeste de América. Dentro de la variación en el patrón de color de esta especie, los ejemplares completamente amarillos se consideraban muy raros u ocasionales. Sin embargo, los patrones amarillos dominan una población establecida en el interior del Golfo Dulce en el Pacífico sur de Costa Rica. Objetivo: Monitoreamos y estudiamos la abundancia, patrones de actividad, morfometría y comportamiento alimentario del H. platurus amarillo dentro del Golfo Dulce. Métodos: Entre febrero 2009 y julio 2018, realizamos búsquedas mensuales de serpientes marinas desde una embarcación dentro del perímetro del Golfo Dulce. Resultados: Los adultos de la población de golfo son más pequeños que la población oceánica bicolor, con las hembras de cuerpos más grandes. Las serpientes del Golfo Dulce flotan y se mueven con las corrientes superficiales sin asociarse con líneas de deriva y escombros. Las serpientes se encuentran principalmente en aguas limpias y tranquilas con poca turbulencia. La dieta se compone de una amplia diversidad de peces pequeños, que capturan con un comportamiento depredador de acecho pasivo, flotando en la superficie. La presa es rápidamente capturada y tragada viva. Esta especie tiene una ausencia casi total de depredación, patrón que se extiende a esta población amarilla. Conclusiones: Las características del golfo y la dirección y fuerza de las corrientes superficiales en su entrada podrían restringir el tránsito de esta población amarilla hacia el exterior y el ingreso de las serpientes bicolores de la población oceánica. No consideramos prudente realizar cambios taxonómicos en esta población. La población amarilla es relativamente abundante dentro de la cuenca. Sin embargo, el alto tráfico turístico y otras actividades son factores de riesgo para su conservación. Políticas de protección deben crearse para preservar y proteger esta pequeña población de serpientes marinas amarillas, única dentro del rango de distribución de esta especie.

SIGNIFICANCE: Surfacing the connections between science engagement, engaged science, and sustainability sciences, we urge a re-evaluation of sustainability science's beneficiaries and goals, by advocating a transdisciplinary approach to address sustainability challenges, based on a relational ontology. Thinking with posthumanist, feminist new materialist and Black feminist theories, we consider the importance of multispecies attention and empathy in scientific research. We propose a concept of evolving new perceptual organs in humans to enhance collective responsiveness, inspired by the lateral line organ in fish and their collaborative intelligence for navigating contemporary social and ecological crises and injustices in 'hot messes'.

ABSTRACT. Using geotechnologies has become fundamental for planning the sustainable expansion of agricultural activities, especially fish farming. The objective of this work was to map and carry out the morphological characterization of the hydrographic micro-basins and their physical aspects, such as slope, altimetry, and land use and occupation, and also to quantify and locate the existing excavated ponds in the municipality of Pato Bragado, in Paraná State. Geotechnology tools and images generated by the free software QGIS and Google Earth were used to create maps of the excavated ponds' physical aspects, quantification, classification, and location. The predominant slope in the municipality is gently undulating, and soy plantation uses 42.99% of the municipality's entire area. The mapping located 190 excavated ponds. Depth measurement was not carried out, but rather mapping concerning water depths representing a total area of 47.86 ha of water blade and nine micro-basins within the municipality of Pato Bragado, with only the Arroio Fundo micro-basin covering 47.37% of all existing excavated ponds. The morphometric indicators concluded that the micro-basins present a minimum risk of flooding, which is ideal for use in fish farming. Making the results of this work available to public managers and fish farmers aims to demonstrate the importance of using geotechnologies for sustainable planning to expand aquaculture activities, which, in this case, are focused on fish farming.

ABSTRACT. Commercial farming of tilapia species has been spread to many countries worldwide to meet the need for animal protein at an affordable price, which has led tilapias to invade natural areas. Consequently, tilapias have established wild populations, causing a great negative impact on native biodiversity. The Sonora River, located in northwest Mexico, has an approximate length of 400 km, and at least four native fish species inhabit it. Nevertheless, the Sonora River has been severely reduced and contaminated by open-pit mining. According to existing knowledge, the presence of tilapias is not reported in the Sonora River; hence, the present study is the first report of the presence of the Nile tilapia Oreochromis niloticus in a site near the town of Baviácora, Sonora, Mexico. The presence of this invasive species may represent a severe threat to the biotic component of this ecosystem, which is already affected by mining pollution.

ABSTRACT. Due to its beneficial biological properties, chitosan extracted from crustacean byproducts emerges as a viable strategy to mitigate the anti-nutritional factors in vegetable-based diets for juvenile white snook (Centropomus viridis). The growth, survival, and nutritional efficiency of juvenile white snook-fed diets containing chitosan were evaluated. Chitosan was extracted chemically and enzymatically from shrimp byproducts (exoskeletons and heads). It was then included in a soybean meal-based diet (48% protein and 19% kJ g-1 gross energy) at 0, 0.5, and 1.0% chitosan levels (D-Control, CHI-0.5%, and CHI-1.0%). Juvenile snook (initial weight: 44.5 ± 4.2 g) were randomly distributed into 300 L tanks and fed the experimental diets three times daily for 45 days. Fish fed the CHI-0.5% and CHI-1.0% diets were significantly (P < 0.05) higher in growth rates than the D-Control diet. No significant differences in survival were observed. The FCR of the CHI-0.5% and CHI-1.0% diets were lower when compared to the D-Control (P < 0.05). The results suggest the utilization of chitosan in diets with high soybean meal content for snook to obtain better growth and survival.

ABSTRACT. Kelp forests support species-rich food webs that predator-prey interactions may sustain. Here, we analyze prey availability and stomach contents of the predatory fish Prolatilus jugularis in an unexplored subtidal kelp forest of Lessonia trabeculata in south-central Chile. In the kelp forest, 42 invertebrate taxa and 1016 individuals were observed. In the diet of P. jugularis, 21 taxa and 130 individuals were identified. Crustacea, particularly amphipods, were the dominant and more frequent taxa in the kelp forest and stomach contents. Annelida and Mollusca were also present in the kelp forest and diets but were less abundant. We did not find a statistically significant correlation between kelp forest and stomach-content prey abundances and frequencies. Also, dominance structure significantly differed between kelps and stomach contents. Our results indicate that P. jugularis could feed in other habitats outside the survey area. Seven predatory fish were sampled in the kelp forest. Pinguipes chilensis was the dominant fish, with 65% of the total fish biomass, followed by P. jugularis with 20%.