Abstract A recent examination of Philometra nematodes from mangrove red snapper Lutjanus argentimaculatus (Forsskal, 1775) from the Karachi coast, Kemari was done in the years 2021–2022. The present study reported three new species of genus Philometra (Costa, 1845) (Nematoda: Philometridae) Philometra kolachii, Philometra lutjani and Philometra kemarii. A total of 140 fish samples were examined, and 76 were infected. The intensity of infected fish was 54.28%. In Pakistan, literature on Philometrid nematodes is limited, therefore, this research would be helpful for the documentation and enhancement of nematods in Pakistan. Forsskal, Forsskal (Forsskal 1775 coast 20212022 2021 2022 2021–2022 Costa, Costa (Costa 1845 Nematoda (Nematoda Philometridae kolachii kemarii 14 examined 7 5428 54 28 54.28% Pakistan limited therefore 177 2021202 202 2021–202 184 1 542 5 2 54.28 17 202120 20 2021–20 18 54.2 20212 2021–2 54. 2021–

Resumo Um exame recente dos nematóides Philometra do pargo vermelho de mangue Lutjanus argentimaculatus (Forsskal, 1775) da costa de Karachi, Kemari, foi feito nos anos 2021 e 2022. O presente estudo relatou três novas espécies do gênero Philometra (Costa, 1845) (Nematoda: Philometridae): Philometra kolachii, Philometra lutjani e Philometra kemarii. O total de 140 amostras de peixes foram examinadas e 76 estavam infectadas. A intensidade de peixes infectados foi de 54,28%. No Paquistão, a literatura sobre os nematóides Philometrid é limitada, portanto, esta pesquisa seria útil para a documentação e aprimoramento dos nematóides no Paquistão. Forsskal, Forsskal (Forsskal 1775 Karachi Kemari 202 2022 Costa, Costa (Costa 1845 Nematoda (Nematoda Philometridae Philometridae) kolachii kemarii 14 7 infectadas 5428 54 28 54,28% Paquistão limitada portanto 177 20 184 1 542 5 2 54,28 17 18 54,2 54,

Abstract In commercial fish farming, growth performance is the most influential factor in economic profitability; so, biomass optimization has become a growing concern. We analyzed the influence of 3 harvest densities (15, 20, and 22 kg·m-3) on the growth of spotted rose snappers reared in floating net cages during a production cycle. To assess the impact of stocking density on growth performance, we used 2 indicators: final total length-at-age (12 months) and the growth rate estimated from growth models (von Bertalanffy, logistic, and Gompertz). For the first indicator, we tested for normality. We did the Kruskal-Wallis and the post hoc Kruskal-Wallis tests to compare the mean total final length from each density. Accordingly, the means of densities D15 and D20 were the same (Pvalue = 0.22). For the second indicator, we fitted the models with the subroutineoptimof the R statistical package using the L-BFGS-B algorithm. Model selection was made with the Akaike and the Bayesian information criteria. Both criteria suggested that the logistic model fitted the data best. With the best model (logistic), we did 1,000 bootstrap simulations for each density scenario to determine the distribution of the maximum likelihood estimation for the instantaneous growth rate. Because the estimates were normally distributed, we used ANOVA to test the equality of the instantaneous growth. The Tukey HSD test suggested that all means were statistically different from each other. The fastest growth rate (K= 0.275) corresponded to the cage with a density of 20 kg·m-3. These findings demonstrate that the logistic model can predict the growth of spotted rose snappers under culture conditions using floating net cages. These results strengthen the productive potential and economic profitability of snapper aquaculture using floating cage and may help the start of commercial scale aquaculture.

Resumen En la piscicultura, el crecimiento es el factor más influyente en la rentabilidad económica. Por tanto, optimizar la biomasa es una preocupación creciente. Se analizó la influencia de 3 densidades de cosecha (15, 20 y 22 kg·m-3) en el crecimiento del pargo flamenco cultivado en jaulas flotantes. Para evaluar el impacto de la densidad de población en el crecimiento, usamos 2 indicadores: la longitud total final por edad (12 meses) y la tasa de crecimiento estimada a partir de modelos de crecimiento (von Bertalanffy, logístico y Gompertz). Para el primer indicador, evaluamos la normalidad. Realizamos la prueba de Kruskal-Wallis para comparar la longitud media total final asociada a cada densidad, seguido de una prueba de Kruskal-Wallispost hoc. Los resultados sugieren que las medias de las densidades D15 y D20 fueron estadísticamente iguales (valor deP= 0.22). Para el segundo indicador, ajustamos los modelos con el paquete estadístico R (algoritmo L-BFGS-B). El modelo se seleccionó con los criterios de información de Akaike y Bayesiano. Ambos criterios sugirieron que el modelo logístico se ajustó mejor a los datos. Con el modelo logístico, hicimos 1,000 simulacionesbootstrappara cada densidad para determinar la distribución de la estimación de máxima verosimilitud para la tasa de crecimiento instantáneo. Como las estimaciones tuvieron distribución normal, usamos un ANDEVA para probar la igualdad del crecimiento instantáneo. La prueba diferencia significativa honesta de Tukey sugirió que todas las medias eran estadísticamente diferentes. La tasa de crecimiento más alta (K= 0.275) correspondió a la densidad de 20 kg·m-3. Estos hallazgos demuestran que el modelo logístico puede predecir el crecimiento del pargo flamenco en condiciones de cultivo. Estos resultados fortalecen el potencial productivo y la rentabilidad económica de la acuicultura de pargos en jaulas flotantes y pueden ser el comienzo de la acuicultura a escala comercial.

Resumen Introducción: El pargo mancha es un pez marino de alto consumo e interés comercial en Costa Rica que está sometido a una fuerte presión pesquera, la cual puede afectar la diversidad genética y generar problemas por depresión endogámica. Objetivo: Evaluar el estado genético de la población de Lutjanus guttatus mediante el uso microsatélites. Métodos: Se recolectaron muestras entre el 2018 y 2019 y se estudiaron 44 individuos de cada una de las localidades del Golfo de Nicoya y Golfo Dulce. Se realizó la extracción de ADN y la amplificación de diez loci con microsatélites mediante PCR, para la determinación del genotipo, análisis de diversidad genética y estructura poblacional. Resultados: Los parámetros de diversidad indican un elevado polimorfismo asociado con un alto número de alelos obtenidos por locus, pero con bajos niveles de heterocigosidad observada en comparación con la esperada (Ho= 0.774 y 0.800 y He= 0.948 y 0.954 para Golfo de Nicoya y Golfo Dulce, respectivamente). No hay evidencia suficiente para decir que las dos poblaciones son distintas (FST= 0.00264, P > 0.05). La desviación del Equilibrio de Hardy-Weinberg indica la posible mezcla de organismos de origen distinto a los del medio silvestre. Conclusiones: L. guttatus tiene niveles altos de diversidad genética, no hay evidencia de diferenciación en subpoblaciones genéticas, lo que en manejo pesquerías se considera una sola población panmíctica. La posible mezcla de individuos de origen distinto al silvestre sugiere la presencia de organismos de un programa de repoblación o de cultivos comerciales en la región. El uso de marcadores genéticos se recomienda para el monitoreo, además, en programas de repoblación y evaluar su efecto.

Abstract Introduction: The spotted snapper is a high-consumption and commercially important marine fish in Costa Rica, subjected to heavy fishing pressures, which can affect genetic diversity and generate problems due to inbreeding depression. Objective: To evaluate the genetic status of the population of Lutjanus guttatus using microsatellites. Methods: Samples were collected between 2018 and 2019, and 44 individuals from each of the localities of the Gulf of Nicoya and the Gulf of Dulce were studied. DNA extraction and amplification of ten loci with microsatellites using PCR were performed, followed by genotyping, analysis of genetic diversity, and population structure. Results: Diversity parameters indicate a high polymorphism associated with a high number of alleles obtained per locus, but with low levels of observed heterozygosity compared to expected (Ho= 0.774 and 0.800, and He= 0.948 and 0.954 for the Gulf of Nicoya and Gulf of Dulce, respectively). There is not enough evidence to say that the two populations are distinct (FST= 0.00264, P > 0.05). Deviation from Hardy-Weinberg equilibrium was recorded, indicating possible mixing of organisms of different origin from the wild environment. Conclusions: L. guttatus presents high levels of genetic diversity, without evidence of differentiation in genetic subpopulations. For fisheries management purposes, they would be considered a single panmictic population. The possible mixing with wild individuals suggests the presence of organisms derived from a restocking or commercial cultivation program carried out in the region. The use of genetic markers is recommended to maintain monitoring, follow up on restocking programs and evaluate their effect.

Resumen: Los pargos de la familia Lutjanidae son un recurso pesquero importante en las costas mexicanas, con reportes de capturas de alrededor de las 12.000 toneladas anuales. El objetivo de este estudio fue determinar si existe variación en las presas consumidas por la familia Lutjanidae en las costas de los océanos Atlántico y Pacífico mexicanos realizando un análisis dietario, basado en los datos publicados, respecto del índice de importancia relativa (IIR) para 12 especies de pargos: Ocyurus chrysurus, Rhomboplites aurorubens, Lutjanus griseus, L. apodus, L. analis, L. synagris, L. campechanus, L. peru, L. guttatus, L. colorado, L. argentiventris y L. novemfasciatus. De acuerdo a los resultados, la dieta de los pargos estuvo integrada principalmente por crustáceos (69%), seguido de peces (28%), y el 3% restante correspondió a otros grupos presa. Se observó que los pargos en su nivel trófico son eficientes en el transporte y flujo de energía de los niveles bajos a los niveles superiores de la red trófica, proviniendo esta energía principalmente de los crustáceos.

Abstract: Snappers of the Lutjanidae family are an important fishing resource off the Mexican coasts, with reports of catches around 12,000 tons by year. The objective of this study was to determine if there is variation in the prey consumed by the Lutjanidae family on the coasts of the Mexican Atlantic and Pacific oceans by performing a dietary analysis, based on published data, regarding the relative importance index (RII) for 12 snapper species: Ocyurus chrysurus, Rhomboplites aurorubens, Lutjanus griseus, L. apodus, L. analis, L. synagris, L. campechanus, L. peru, L. guttatus, L. colorado, L. argentiventris and L. novemfasciatus. Snapper diets were composed mainly of crustaceans (69%), followed by fishes (28%) and the remaining 3% corresponded to other prey. It can be assumed that snappers are efficient vehicles to transport energy from low to high trophic levels in the food web, coming this energy mainly from crustaceans.

ABSTRACT The free amino acids (FAAs) profile and its variations during the embryonic development and yolk-sac larvae of Pacific red snapper Lutjanus peru are described. The concentration of 15 FAAs (nine essentials and six non-essentials) was evaluated by reverse-phase high-performance liquid chromatography. The fertilized eggs of L. peru contain a small concentration of FAAs (4.77 ± 0.89 nmol ind−1). However, the variations in the FAAs pool during the early development are similar to the changes reported in other species with small pelagic eggs. The essential free amino acids are more abundant than the non-essential free amino acids throughout the studied period. During the egg stage, an increase in the FAAs was observed, and after hatching, isoleucine, leucine, lysine, and alanine were the FAAs that decreased the most during the yolk-sac larvae stage. The hatching rate was correlated with the total FAAs, the fraction of essential free amino acids, and the concentrations of glutamic acid, threonine, and valine in the egg stage, suggesting a possible role as a determinant in egg quality. Further studies are required to assess the role of FAAs in other aspects of egg development, like fertilization rate and egg buoyancy.

Abstract The spotted rose snapper, Lutjanus guttatus, is an important fishery species with high potential for aquaculture. Genetic characterization of its natural populations is necessary to avoid stock collapse and loss of genetic diversity. Previous studies carried out in the Tropical Eastern Pacific (TEP), however, have shown contrasting results in the genetic structure of fish populations, particularly in species of Lutjanidae. Therefore, to understand the genetic structure of spotted rose snapper in the TEP, twelve microsatellite loci were used to assess the genetic diversity and explore the hypothesis of population genetic structure in samples of the species collected throughout the TEP. Fin clips from 186 sampled individuals (27 to 49 per site) were analyzed from five sites in the three regional biogeographic provinces, delimited by shoreline reef habitat breaks: La Paz (Cortez province), Colima and Oaxaca (Mexican province), Chiriqui and Port of Panama (Panamic province). Results of global Analysis of Molecular Variance (AMOVA), population pairwise FST, hierarchical AMOVA, and a discriminant analysis of principal components (DAPC) reflected a panmictic population involving the entire set of sampled sites. The role of larval dispersal, post-recruitment migration, and marine current dynamics as drivers of genetic connectivity in this species is discussed. guttatus aquaculture TEP , (TEP) however Lutjanidae Therefore 18 27 (2 4 site provinces breaks Cortez province, province province) Mexican Panamic province. . AMOVA (AMOVA) FST DAPC (DAPC dispersal postrecruitment post recruitment migration discussed (TEP 1 2 ( (AMOVA

Resumen El pargo lunarejo, Lutjanus guttatus, es una importante especie pesquera, con alto potencial para la acuicultura. La caracterización genética de sus poblaciones naturales es necesaria para evitar el colapso del stock y la pérdida de diversidad genética. Sin embargo, estudios previos realizados en el Pacífico Oriental Tropical (TEP), han mostrado resultados contrastantes en la estructura genética de poblaciones de peces, particularmente en especies de Lutjanidae. Por lo tanto, para entender la estructura genética del pargo lunarejo en el TEP, se usaron 12 loci microsatélites para evaluar la diversidad genética y explorar la hipótesis de estructura genética poblacional en muestras de la especie colectada a lo largo del TEP. Se analizaron fragmentos de aletas de 186 individuos (27 a 49 por sitio) de cinco localidades en las tres provincias biogeográficas regionales, delimitadas por las discontinuidades de hábitat de arrecife costero: La Paz (Provincia de Cortés), Colima y Oaxaca (Provincia Mexicana), Chiriquí y Puerto de Panamá (Provincia Panámica). Los resultados del Análisis de Varianza Molecular (AMOVA) global, FST de poblaciones pareadas, AMOVA jerárquico y un análisis discriminante de componentes principales (DAPC) reflejaron una población panmíctica que involucraba todo el conjunto de sitios muestreados. Se discute el papel de la dispersión larvaria, migración post-reclutamiento y la dinámica de las corrientes marinas como propulsores de la conectividad genética en esta especie. guttatus pesquera acuicultura embargo TEP , (TEP) peces Lutjanidae tanto 1 18 27 (2 4 sitio regionales costero Provincia Cortés, Cortés Cortés) Mexicana, Mexicana Mexicana) Panámica. Panámica . Panámica) (AMOVA global pareadas DAPC (DAPC muestreados larvaria postreclutamiento post reclutamiento (TEP 2 (

Abstract In this study, we tested the taxonomic validation of red snappers species (Southern red snapper Lutjanus purpureus; Silk snapper L. vivanus; Blackfin snapper L. buccanella; and Pacific red snapper L. peru) based on comparative analysis, using four methods for species delimitation. These methods were based on either genetic similarity or phylogenetic trees inferred from two mitochondrial (Cytochrome b and D-loop) and two nuclear (Myostatin and S7 introns) markers. On one hand, the genetic results corroborated the presence of four red snapper species, confirming their taxonomic validation despite their remarkable morphological similarity. On the other hand, few incongruencies in the species delimitation methods were observed according to the phylogenetic reconstruction method (maximum likelihood or Bayesian inference) when using. Based on the phylogenetic results, L. buccanella should represent a more ancient lineage in relation to the clade that encompasses L. purpureus, L. peru and L. vivanus. The single-locus phylogenetic analysis based on Cytb recovered each the red snapper species as a well-supported clade. Overall, this study provided a DNA-based validation of the traditional morphological taxonomy of red snappers. Southern purpureus L vivanus Cytochrome Dloop D loop D-loop Myostatin S introns markers hand maximum inference singlelocus single locus wellsupported well supported Overall DNAbased DNA

Resumen Introducción: El Pacífico Norte de Costa Rica es una región diversa y productiva; sin embargo, tenemos un escaso conocimiento sobre el estado de los recursos marinos y la dinámica pesquera, particularmente de la pesca artesanal en el Golfo de Santa Elena, uno de los principales caladeros de la zona. Objetivo: Caracterizar la dinámica de esta pesquería. Métodos: Se analizaron los datos recopilados por el Instituto Costarricense de Pesca y Acuicultura y las facturas pesqueras de los sitios de desembarque para el período 2010-2019. Resultados: Hubo una alta variación en la biomasa desembarcada, sin embargo, la captura total por unidad de esfuerzo (CPUE; kg/día) y de las principales especies objetivo no disminuyó significativamente. En general, hubo una CPUE más baja en los meses de surgencia (diciembre-abril). De las 42 especies comerciales reportadas, la mayor biomasa provino del pargo mancha (Lutjanus guttatus; 22 % de la biomasa), el pargo seda (L. peru; 18 %), las cabrillas (Epinephelus spp.; 15 %) y el pulpo (Octopus spp., 13 %). Conclusiones: La CPUE en Santa Elena no ha disminuido significativamente de 2010 a 2019, pero disminuye en la época de surgencia.

Abstract Introduction: The North Pacific of Costa Rica is a diverse and productive region; however, we have a poor understanding of the status of marine resources and fisheries dynamics, particularly for the artisanal fishery in the Gulf of Santa Elena, one of the main fishing grounds of the area. Objective: To characterize the dynamics of this fishery. Methods: We analyzed data collected by the Instituto Costarricense de Pesca y Acuicultura, and sales invoices from landing sites for the period 2010-2019. Results: There was high variation in the landed biomass, however, total catch per unit effort (CPUE; kg/day) and of the main targeted species did not decrease significantly. Overall, there was a lower CPUE in upwelling months (December-April). For the 42 commercial species reported, most biomass was from the spotted rose snapper (Lutjanus guttatus; 22 % of biomass), the Pacific red snapper (L. peru; 18 %), groupers (Epinephelus spp.; 15 %) and octopuses (Octopus spp., 13 %). Conclusions: CPUE at Santa Elena has not declined significantly from 2010 to 2019, but it falls in the upwelling season.

RESUMEN Con el propósito de evaluar el estado del pargo rayado Lutjanus synagris a partir de datos limitados de longitudes provenientes de los desembarcos de las capturas de la pesca artesanal registradas entre 2006 y 2012 en los Parques Nacionales Naturales Tayrona y Corales del Rosario y de San Bernardo y la Vía Parque Isla de Salamanca, se aplicaron indicadores simples y la metodología árbol de decisiones. Se observó un patrón de selectividad en la captura mayoritaria de ejemplares inmaduros (<L mat ) y un nivel de biomasa desovante inferior al punto de referencia límite objetivo, afectando la renovación natural de los stocks de L. synagris. También se ratificó el grado de sobrepesca por crecimiento y reclutamiento. Propender por la disminución de la presión sobre el pargo es un objetivo de manejo que requiere mayor protección en las tres áreas protegidas como zonas fuente, así como un ordenamiento regional participativo para la sostenibilidad del recurso. Por tanto, se recomienda llegar a acuerdos de conservación que propendan por una pesca responsable de peces maduros. Esto, permitirá un máximo rendimiento en biomasa y mejores ingresos económicos para los pescadores. Se propone la metodología descrita para la evaluación de otros recursos aprovechados en las áreas protegidas.

ABSTRACT With the purpose of evaluating the status of the lane snapper Lutjanus synagris from limited catch length data from the landings of artisanal fishing catches recorded between 2006 and 2012 in Tayrona and Corales del Rosario y de San Bernardo National Parks, and the Vía Parque Isla de Salamanca, simple indicators and the decision tree methodology were applied. it was observed that this indicator mostly configured a selectivity pattern represented in capture of mayoritary immature specimens (<L mat ) and a spawning biomass level lower than the target reference point, affecting the natural renewal of L. synagris stocks. Also, it was ratified the degree of overfishing for growth and recruitment to which L. synagris is subjected. Reducing pressure on snapper resource is a management objective that requires greater protection in the three protected areas for their ability to export the resource, as well as participatory regional fisheries management for the sustainability of the resource. Therefore, it is recommended to reach conservation agreements that promote responsible fishing of mature fish. This objective will allow maximum biomass yield, and better economic income for fishers. We also propose to apply the methodology described in this study to evaluate other fishery resources caught in the protected areas.

Resumen. Como base de supervivencia y desarrollo, el alimento de los peces representa una línea base para investigaciones sobre aspectos ecológicos relacionados con la estructura y la función de comunidades marinas. El presente estudio se orientó hacia los hábitos alimentarios del huachinango del Pacífico, Lutjanus peru, en Santa Rosalía, Baja California sur (México), durante agosto de 2016 hasta octubre de 2017. Un total de 403 especímenes fueron analizados y categorizados de acuerdo con el sexo, la madurez sexual y la estación climática. El intervalo de tallas fue de 21 a 60 cm de longitud total, y el peso varió de 195 a 1,920 g. En total, se identificaron 29 especies presa, incluidos peces (13 ítems), crustáceos (11 ítems), moluscos (4 ítems) y tunicados (1 ítem). De acuerdo con el índice porcentual de importancia relativa, las principales presas fueron Sardinops sagax (47.65%), Nycthiphanes simplex (38.50%), Harengula thrissina (11.21%), Myctophidae (0.68%) y Benthosema panamense (0.52%). Las presas fueron consumidas en diferentes proporciones de acuerdo con el sexo (F = 2.01, P < 0.049), la madurez sexual (F = 4.99, P < 0.001) y la estación climática (F = 45.52, P < 0.001). La amplitud trófica fue estrecha (B i = 0.16); esta fue consistente con la gráfica de Costello, la cual mostró un consumo principal sobre presas gregarias de origen pelágico-costero y mesopelágico. El huachinango del Pacífico en Santa Rosalía fue un consumidor terciario. Su alimentación oportunista incluyó pocos, pero abundantes ítems presa, y la composición trófica fue distinta a la de L. peru en otras áreas del golfo de California y la costa mexicana del Pacífico.

Abstract. A biological basis for survival and development, the diet of fish represents a baseline for research on ecological aspects related to the structure and function of marine communities. This study focused on the feeding habits of the Pacific red snapper, Lutjanus peru, in Santa Rosalía, Baja California Sur (Mexico), during August 2016 through October 2017. A total of 403 specimens were analyzed and categorized by sex, sexual maturity, and season. The size interval ranged from 21 to 60 cm total length, and the weight ranged from 195 to 1,920 g. A total of 29 prey items were identified, including fish (13 items), crustaceans (11 items), mollusks (4 items), and tunicates (1 item). According to the index of relative importance, the main prey were Sardinops sagax (47.65%), Nycthiphanes simplex (38.50%), Harengula thrissina (11.21%), Myctophidae (0.68%), and Benthosema panamense (0.52%). Prey were consumed in different proportions according to sex (F = 2.01, P < 0.049), sexual maturity (F = 4.99, P < 0.001), and season (F = 45.52, P < 0.001). The trophic width was narrow (B i = 0.16); this was consistent with the Costello graph, which showed the consumption of mainly pelagic-coastal and mesopelagic gregarious prey. The Pacific red snapper in Santa Rosalía functioned as a tertiary consumer. Its opportunistic diet included few highly abundant prey items, and the diet composition differed from that of L. peru in other areas of the Gulf of California and the Pacific coast of Mexico.

ABSTRACT The effect of diets with varying crude protein-to-precooked cornstarch (P:S) ratios on growth performance, feed efficiency, carbohydrase activity, and blood chemistry of juvenile Lutjanus guttatus was evaluated. Four isoenergetic (19.0 kJ g−1) diets containing different P:S ratios (46:18, 38:30, 34:35, and 31:40) were formulated to feed fish for ten weeks in triplicate. Each diet was tested in triplicate in groups of 35 fish per tank (average body weight 19.4 ± 0.3 g) to apparent satiation three times a day. The weight gain, specific growth rate, and feed conversion ratio obtained with P38S30 and P34S35 were not significantly different vs. P46S18. Survival does not present significant differences among treatments. Biological indices (condition factor, hepatosomatic index, viscerosomatic index, and intraperitoneal fat rate) showed no significant differences among treatments. Body protein content decreased significantly with increasing precooked cornstarch concentration, while body lipid levels increased. Blood chemistry values were within those of healthy juveniles, except for glucose values. An increase in pancreatic α-amylase and intestinal α-glucosidase blood chemistry values were within those of healthy juveniles, except for glucose values. An increase in pancreatic α-amylase and intestinal α-glucosidase levels concomitant with increasing precooked cornstarch concentration showed the capacity of juvenile L. gutattus to digest high precooked cornstarch levels. Growth performance, biological indices, and hematological parameters showed that L. guttatus could digest and metabolize up to 35% of precooked cornstarch through increased plasma glucose levels and the α-amylase and α-glucosidase activities. Without negative effect on growth performance.

Resumen La base tecnológica para la acuicultura del Lutjanus guttatus fue desarrollada en Costa Rica desde el 2002 por el Parque Marino del Pacífico. Las primeras producciones en masa de juveniles se obtuvieron en el 2005, las granjas comerciales a pequeña escala se establecieron a partir del 2006 y la primera transferencia de tecnología al sector privado inició en el 2008. A partir de estos avances se identificó la necesidad de optimizar la producción de juveniles. Con este objetivo, se evaluaron y describieron biológicamente tres cultivos larvarios obtenidos de desoves naturales de reproductores de segunda generación (F2). Tres familias n = 8 cada una; 1,45 ± 0,21 kg; 1,33 ± 0,12 kg; y 1,28 ± 0,10 kg provenientes de una granja acuícola se aclimataron en el laboratorio hasta que desovaron. Se incubaron 100 mil huevos por desove (densidad: 520 huevos mL-1). Las larvas (90 mil/tanque) fueron sembradas con una longitud total (Lt) inicial de 2,25 mm y alimentadas con rotíferos enriquecidos, microalgas producidas en fotobiorreactores helicoidales y nauplios de artemia. El crecimiento, sobrevivencia, canibalismo, variabilidad del tamaño y deformidades presentadas fueron registradas. Un total de 22 837 juveniles fueron cosechados en el día 60 después del desove. Durante la cosecha se obtuvo una longitud total del juvenil (Lt) de 57,8 ± 7,82 mm, tasa de crecimiento absoluto (TCA) 0,93 mm d-1, tasa de crecimiento específico (TCE) 5,41 % d-1, factor de condición (K) 1,089; una sobrevivencia promedio de 8,4 % y 6,3 % de deformidades totales a la vista. Las metodologías utilizadas para obtener un desove natural de calidad, la mejora de alimento vivo producido por fotobiorreactores y la separación por tamaño fueron aspectos efectivos para el cultivo larval de la especie, aunque la inanición en los primeros días de alimentación exógena, la metamorfosis y el canibalismo siguen siendo factores que afectan la sobrevivencia final.

Resumo A base tecnológica para a aquicultura do Lutjanus guttatus foi desenvolvida na Costa Rica desde 2002 pelo Parque Marino do Pacífico. As primeiras produções em massa de juvenis do Luciano foram obtidas em 2005, os viveiros comerciais de pequena escala foram estabelecidos a partir de 2006 e a primeira transferência de tecnologia ao setor privado iniciou em 2008. A partir desses avanços, identificou-se a necessidade de otimizar a produção de juvenis. Com este objetivo, foram avaliados e descritos biologicamente três cultivos larvais obtidos de desovas naturais de reprodutores de segunda geração (F2). Três famílias n = 8 cada; 1,45 ± 0,21 kg; 1,33 ± 0,12 kg; e 1,28 ± 0,10 kg, provenientes de um viveiro aquícola, foram aclimatadas no laboratório até a desova. Foram incubados 100 mil ovos por desova (densidade: 520 ovos mL-1). As larvas (90 mil/tanque) foram plantadas com uma longitude total (Lt) inicial de 2,25 mm e alimentadas com rotíferos enriquecidos, microalgas produzidas em fotobiorreatores helicoidais e náuplios de artemia. Houve o registro do crescimento, da sobrevivência, do canibalismo, da variabilidade do tamanho e das deformidades apresentadas. Foram coletados no total 22 837 juvenis no dia 60 depois da desova. Durante a coleta, obteve-se foram obtidos uma longitude total do juvenil (Lt) de 57,8 ± 7,82 mm, taxa de crescimento absoluto (TCA) 0,93 mm d-1, taxa de crescimento específico (TCE) 5,41% d-1, fator de condição (K) 1,089; e uma sobrevivência média de 8,4% e 6,3% de deformidades totais da vista. As metodologias utilizadas para a obtenção de uma desova natural de qualidade, a melhora de alimento vivo produzido por fotobiorreatores e a separação por tamanho foram aspectos efetivos para o cultivo larval da espécie, ainda que a inanição nos primeiros dias de alimentação exógena, a metamorfose e o canibalismo sigam sendo fatores que afetam a sobrevivência final.

Abstract The technological foundation of the Lutjanus guttatus aquaculture was developed in Costa Rica in 2002 by Parque Marino del Pacífico. The first juvenile mass production was obtained in 2005; small-scale commercial farms were established in 2006; and the first technology transfer to the private sector began in 2008. Based on these advances, the need to optimize the production of juveniles was identified. With this objective, three larval crops obtained from natural spawning of second-generation (F2) breeders were evaluated and biologically described. Three families n = 8 each: 1.45 ± 0.21 kg, 1.33 ± 0.12 kg, and 1.28 ± 0.10 kg from an aquaculture farm were acclimatized in the laboratory until they spawned. A total of 100,000 eggs were incubated per spawning (density: 520 eggs mL-1). Larvae (90 thousand/tank) were seeded with an initial total length (TL) equal to 2.25 mm and fed with enriched rotifers, microalgae produced in helical photobioreactors, and artemia nauplii. Growth, survival, cannibalism, size variability, and deformities obtained were registered. A total of 22,837 juveniles were harvested on day 60 after spawning. During harvest, the juvenile’s total length (TL) was 57.8 ± 7.82 mm, Absolute Growth Rate (AGR) was 0.93 mm d-1, Specific Growth Rate (SGR) was 5.41% d-1, Condition Factor (K) was 1.089, average survival was 8.4 % and total eye deformities were 6.3 %. Methodologies used to obtain natural quality spawning, improvement of live food produced by photobioreactors, and separation by size were effective aspects for the larval culture of the species, although starvation in the first days of exogenous feeding, metamorphosis, and cannibalism continue to be factors affecting final survival.

ABSTRACT Pacific red snapper (Lutjanus peru) is an important commercial species in Mexico with great aquaculture potential; however, digestive physiology is still unknown. Therefore, the objective of the present work was to characterize the digestive proteases of L. peru juvenile using biochemical and electrophoretic techniques. Results showed a higher acid protease activity than the alkaline proteases, trypsin, chymotrypsin, and leucine aminopeptidase (LAP). The optimum temperature for acid proteases was between 30 to 40°C. Trypsin activity showed two maximum peaks of temperature (30 and 50°C), while alkaline proteases, chymotrypsin, and LAP had optimum temperatures of 50, 50 to 60, and 40°C, respectively. Moreover, the optimum pH of acid proteases was between 2 and 3. Also, alkaline proteases, trypsin, chymotrypsin showed pH optimums at pH 6, 9, and 5, respectively, although LAP showed two optimum pH values at 6 and 9. Acid protease zymogram showed three isoforms, totally inhibited by pepstatin A. Alkaline protease zymogram revealed six bands (125.4, 67.2, 57.9, 48.6, 29.8, and 26.9 kDa), which were inhibited by specific serine-proteases and metalloproteases inhibitors. In conclusion, the main digestion in L. peru depends on stomach proteases, which are characteristic of carnivorous fish, followed by intestinal digestion supported mainly by chymotrypsin.

EXTENDED ABSTRACT A sedimentological study of the prograding area of the Paraná River delta (PRD) is here presented with the aim of characterizing the deposits related to the last ~100 yr. of paleoenvironmental evolution and to contribute to facies models of bayhead deltas. Delta deposits are the result of the interaction of various processes and factors (principally hydrological characteristics, waves, tidal action, type and volume of sedimentary discharge, water depth, sea level, climate) that disperse the sediments transported to the river mouth (Wright, 1977). The Paraná River, together with the contribution of the Uruguay River, develops a bayhead delta into the Río de la Plata (RdP) estuary (Fig. 1a). The delta constitutes an extensive plain with a very low gradient, lined by numerous fluvial channels of diverse hierarchy, and a series of distributary mouth bars with a lobate morphology (Figs. 1c, 2). It is a fluvial-dominated delta, regulated by the hydrological regime of its drainage basin and modulated by the estuary dynamics (Iriondo, 2004; Cavallotto et al., 2005). This bayhead delta has a drainage area of 3.000.000 km2. The Paraná river supplies 160 million tons of sediment per year to the delta mouth, with ~145 million tons of suspended sediments (30% clays, 60-65% silts and 5-10% sands) and 15 million tons of sands as bottom load (Sarubbiet al., 2004). In the Uruguay River, the suspended load reaches 7 million tons per year of sediments, with a higher contribution of sandy bottom sediments (Urien, 1972). Several studies revealed a high-constructive dynamic for the Paraná river delta during the last decades, with progradation rates of 30 to 70 m per year since AD 1818 (Soldano, 1947; Codignotto and Marcomini, 1993; Pittau et al., 2007; Leal, 2011; Medina and Codignotto, 2013). In particular, the study area grew an average of 42-45 m per year between AD 1933-2016 (Marcomini et al., 2018; Fig. 3). The PRD is placed at a temperate zone of southern South America, under a subhumid, mesothermal climate (periods 1981-1990 and 1991-2000; National Meteorological Service, 1992, 2003). Winds are mainly from the northeast and the southeast quadrants (Simionato and Vera, 2002), and are the main forcing of the RdP estuary circulation (Moreira et al., 2016). The estuary experiences a microtidal regime and the wave energy in the inner estuary is low (in average lower than 0.6 m high) and local (Moreira, 2016). Strong southeasterly wind (sudestada), that can last several days, triggers storm surges in the estuary and extensive floods in coastal areas (Seluchi, 1995). On the opposite, when ebb tides are accompanied by intense northeasterly winds, a very low water level happens (Simionato et al., 2004). Fitogeographically, the PRD belongs to the Neotropical region, and the vegetation is strongly influenced by the landscape and the hydrologic regime (Kandus et al., 2006). At the subaerial deltaic plain, plant communities are characterized by riparian forest along the levees and graminoid type plants in the interior, while bulrush colonizes the proximal subaqueous delta (Fig. 4d). Materials and methods include a geomorphologic-temporal evaluation, in-situ survey and sampling of surficial sediments and sediment cores in the lower subaerial and proximal subaqueous delta plains (34° 26’S, 58° 30’ W; Fig. 3), accompanied by lab determinations and then facies analysis. Surficial sediments were sampled with a Snapper dredge and the sediment cores were extracted using 2.5 inches PVC tubes. Grain size was measured with a Malvern Mastersizer Hydro 2000 laser analyzer, after pretreatment to eliminate organic content by soaking samples in hydrogen peroxide solution (H2O2) and rinsed with distilled water. The textural results were statistically processed and evaluated following the Folk and Ward (1957) protocols (Table 1). Due to the common presence of heterolithic sediments and in order to obtain an improved interpretation of the relationship between grain size distribution and sedimentary processes, extreme member (EM) analysis (after Paterson and Heslop, 2015) was applied to identify subpopulations (parametric curve-fitting applying the Weibull distribution; Fig. 5). EM modelling of the studied deposits was guided by geologic criteria and examined in terms of sediment availability and transport-deposition processes, including particle trapping due to bulrush vegetation (a common process in the PRD). The textural characterization by means of ME results a convenient technique to interpret mixed sediments like the here studied. Particularly, it can be useful when the sediment sample are acquired with dredges or augers, methods that produce the loss of sedimentary structures but demand less time and logistics than to extract cores. Sediment cores were described in terms of grain-size, sedimentary structures, color (Munsell, 2000), biological remains, mass magnetic susceptibility (SM, using a Bartington MS2B sensor) and percentage of LOI550 and LOI950. The time constrain for the core successions (ca. 1915-2017) was inferred by means of two main elements: correlation with a sediment core extracted about 15 km to the north of our study area and dated using radionuclide dating (210Pb and 137Cs) by (Schuerch et al., 2016) and the presence and depth of shells of Corbícula fluminea (Table 2), invader bivalve first recorded in the RdP estuary by ca. 1970 (Ituarte, 1981). The vertical growth rate of 1.52 cm per year (since year 1960) estimated for that core, that shows a comparable thickness and grain-size trend and represents a similar subaqueous delta subenvironment (Schuerch et al., 2016), was used in the here study sediment cores (Table 3). In a couple of studied cores there is some inconsistency between the two elements, possibly due to a higher rate of sedimentation. Besides, it is important to notice these estimations are relative age that have a degree of uncertainty due to these organisms not necessary may appear in all the sampled sites. The inferred relationships of grain-size subpopulations and sediment transport-deposition, the analysis of the sediment cores (Figs. 6,7) and the evaluation of the geomorphological setting of surficial and core samples, allow proposing a series of lithofacies (Table 2) and facies associations (Table 4). Core location in a time series of aerial photograph and Google Earth® images (Fig. 3) and previous delta models and concepts (mainly those by Wright and Coleman, 1973; Coleman and Wright, 1975; Wright, 1977; Orton and Reading, 1993) were applied in the facies analysis. Principally, the theoretical model of friction-dominated effluents proposed by Wright (1977) can be applied to the PRD, developed in a shallow basin (inner estuary is less than 4 m deep; Urien, 1972; Fig. 2) that promotes turbulent bed friction. The distributary mouth bars are laterally extensive (several km2), with very low slope (Fig. 4a-c) and crossed by shallow tidal channels. Bars are made up of massive or horizontal laminated beds forming heterolithic beds (sandy and muddy silt) and few fine-very fine sand and silty sand (bar crest) (Facies association F1, Table 4; Figs. 6, 7). This is interpreted as quick accumulation of tractive sediments, due to friction at the shallow river mouth, and then reworked by semidiurnal tidal currents and exceptional storm surges and accompanied by settling of fines from suspension. Once these shoals are stabilized by bulrush vegetation the sedimentation is dominated by suspension and particle trapping by vegetation (Fig. 4d), with eventual very low currents. Finally, the bar becomes an island of the lower subaerial delta plain, dominated by accumulation from flooding events. During this final stage clayey silt and silty clay, with the largest values of LOI550 of all core sediments, are deposited by flooding from the distributary channels (Facies association F5). Facies association F2 represents high energy deposition of sand and silty sand, usually with shells, due to exceptional storm surges or fluvial flooding. Deposits of interdistributary bays (Fig. 4e), included in facies association F4, are dominated by horizontal and heterolithic laminated, clayed silt with low LOI550 (Figs. 6,7). Deposits of subaqueous distributary channel (Fig. 4f) are fine-very fine sand and silty sand interlayered with silt and muddy silts with heterolithic laminations (Facies association F3a, Figs. 6,7). In core D11-T2 a succession with interbedded fine-very fine sand and sandy silt-silt with inclined heterolithic stratification (HIS) was identified (Facies association F3b, Fig. 7), and interpreted as subaqueous channel deposits, developed next to distributary bars (Fig. 3e). The textural characterization by means of ME proves to be a convenient technique to interpret mixed sediments like the here studied. Particularly, it can be useful when the sediment sample are acquired with dredges or augers, methods that produce the loss of sedimentary structures but demand less time and logistics than to extract cores. The proposed lithofacies and facies association will allow to systematize the sedimentological studies of the DRP and research of prograding deposits of bayhead deltas fed by big rivers with a sandy silt load.

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ABSTRACT This study was conducted to evaluate juveniles’ Ocyurus chrysurus (13.7 ± 0.45 g initial weight) to utilize lipid as an energy source on growth, feed efficiency, body composition, digestive and hepatic enzyme activities. Four diets of two protein levels (40 and 50%) with two lipid levels (6 and 12%) and 2% of digestible carbohydrates were formulated. Fish were fed for 60 days to apparent satiation at a stocking density of 10 fish per tank (100 L). Growth gain of fish fed 50% dietary protein was higher than of fish fed 40% dietary protein (P < 0.05). However, feed efficiency was significantly higher at 12 than 6% of dietary lipid. Whole-body lipid and glycogen in the liver increased dramatically with dietary lipid content-alkaline protease activity trend increased as dietary protein increased. Trypsin activity increased significantly as dietary lipid decreased, whereas chymotrypsin activity showed the opposite trend (P < 0.05). Bile salt-dependent lipase activity trend towards increasing as dietary energy decreased. Glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconate dehydrogenase (6PGDH), and fructose-1, 6-biphosphatase (FBPase) significantly increased with increasing dietary lipid levels. However, alanine aminotransferase (ALT) activity increased with dietary protein content. On the other side, pyruvate kinase (PK) activity increased with both dietary protein and lipid content. This study indicates that high dietary lipid (12%) improved the feed efficiency but did not reduce dietary protein demand in juveniles O. chrysurus.