ABSTRACT The objective of this study was to analyze the brachyuran crab assemblages associated with shrimp fishing on the central-southern coast of Veracruz. Information was collected using 46 trawls organized within nine fishing quadrants. The total catch shrimp, bycatch, and discard were recorded and standardized (CPUE kg h−1). Value index by species, species richness, diversity using Shannon and Weaver index, and equitability were determined. A total of 3055 individuals were collected, which corresponded to nine families, 13 genera, and 14 species. Achelous spinicarpus species were identified at the greatest relative abundance (77.74%). Four new species records for the zone: Hepatus pudibundus, Iliacantha liodactylus, Leiolambrus punctatissimus, and Platylambrus granulatus. Species richness varied according to fishing quadrant and depth interval assessed. The highest value of species richness was eight, and observed Margalef species richness index values ranged from 0 to 2.23. The diversity values ranged from 0 to 2.41 bits ind−1; this may indicate that a few species share the greatest impact of trawling. The presence of lagoon systems was determined to define a portion of the composition of the assemblage. Understanding assemblage structure is important to improve knowledge on the impact of shrimp trawling activity on the ecosystem.

Abstract We evaluated the composition, distribution, and abundance of the decapod genera at different developmental stages of larvae and adult macro-crustaceans along the coastline of the Parque Nacional Sistema Arrecifal Veracruzano, SW Gulf of Mexico. Collections were made using light traps. Temperature, salinity, oxygen, and pH were measured in situ. The samples were fixed with 70 % alcohol, separated, and identified by developmental stage and genus level with specialized literature. The Olmstead-Tukey test, the Shannon-Wiener diversity index, and Pielou equitability test were applied. Canonical correlation and cluster analysis were performed. In total, 20,049 individuals of 56 stage-genera were collected, with Potimirim Holthuis, 1954 postlarvae being the most abundant ones. The most abundant taxa were Potimirim at Playa Martí, Macrobrachium Spence Bate, 1868 at Plaza de la Soberanía, and Pachygrapsus Randall, 1840 at Playa Villa del Mar and Playa Tortugas. At Playa Villa del Mar, the highest diversity was found (3.47 bits*individuals-1), and this is related to the complexity of the site. In May, the greatest diversity (3.64 bits*individuals-1) was found, related to the time of reproduction of most of the stage-genera. Most stage-genera were classified as rare. Cluster analysis resulted in two groups, one containing taxa found in cold and wet months and the other of taxa found in dry months. Thus, the dynamics of the taxocene structure is determined by the lifecycles of the species, responding to the migration, reproduction, and colonization of each stage-genera.

ABSTRACT Background: The Parque Nacional Sistema Arrecifal Veracruzano (PNSAV) is in the southern Gulf of Mexico and supports an important shrimp fishery based on three species of Dendrobranchiata: the brown shrimp, Penaeus aztecus, the white shrimp, P. setiferus and the pink shrimp, P. duorarum. Objective: Analyze the distribution and abundance of P. aztecus during the mysis stage and determine its relationship with environmental factors in the PNSAV. Methods: We measured temperature, salinity, and dissolved oxygen in situ. The planktonic samples from four transects were collected during cold fronts and rainy weather conditions from 2011 to 2013. Results: In rainy conditions the temperature varied from 27.49 ± 0.46 to 29.98 ± 0.02°C, salinity from 32.18 ± 0.06 to 35.40 ± 0.52, and dissolved oxygen from 3.64 ± 0.13 to 6.18 ± 0.64 mgL-1; during cold fronts the temperature varied from 23.21 ± 0.05 to 25.74 ± 0.37 °C, salinity from 34.59 ± 0.39 to 35.84 ± 0.17, and dissolved oxygen from 4.04 ± 0.06 to 6.02 ± mgL-1. The highest average density with 6,938 ± 326 mysis 100 m−3, was found during rainy season in 2011 in the southern transect nearshore, followed by 3,321 ± 339 mysis 100 m−3 in the offshoresouth-central transect during cold fronts weather conditions in 2013, and 3,056 ± 236 mysis 100 m−3 in the south-central foreshore transect during cold fronts weather condition in 2011. Conclusions: The highest density of P. aztecus during mysis stage was recorded in southward foreshore area from PNSAV, during rainy conditions and related to large values of dissolved oxygen concentrations.

RESUMEN Antecedentes: El Parque Nacional Sistema Arrecifal Veracruzano (PNSAV) está ubicado en el sur del Golfo de México y soporta una importante pesquería de camarones basada en tres especies de Dendrobranchiata: el camarón café, Penaeus aztecus, el camarón blanco, P. setiferus y el camarón rosado, P duorarum. Objetivo: Analizar la distribución y abundancia de P. aztecus en estadio de mysis y determinar su relación con los factores ambientales en el PNSAV. Métodos: Se midió la temperatura, la salinidad y el oxígeno disuelto in situ. Se recolectaron muestras planctónicas de cuatro transectos durante frentes fríos y condiciones climáticas lluviosas de 2011 a 2013. Resultados: La temperatura varió de 27.49 ± 0.46 a 29.98 ± 0.02 °C, la salinidad de 32.18 ± 0.06 a 35.40 ± 0.52 y el oxígeno disuelto de 3.64 ± 0.13 a 6.18 ± 0.64 mgL-1 en época de lluvias. Durante los frentes fríos, la temperatura varió de 23.21 ± 0.05 a 25.74 ± 0.37 °C, la salinidad de 34.59 ± 0.39 a 35.84 ± 0.17 y el oxígeno disuelto de 4.04 ± 0.06 a 6.02 ± mgL-1. La densidad media más alta fue de 6,938 ± 326 mysis 100 m−3, que se encontró durante las lluvias en 2011 en el transecto sur, cercano a la costa, seguido por 3,321 ± 339 mysis 100 m−3 en el transecto centro-sur, costa afuera durante los frentes fríos en 2,013 y 3,056 ± 236 mysis 100 m−3 en el transecto centro-sur durante los frentes fríos en 2011, en la zona de la costa. Conclusiones: La mayor densidad de mysis de P. aztecus se registró en la zona de playa al sur del PNSAV, durante las condiciones de lluvia y se relacionó con el aumento de las concentraciones del oxígeno disuelto.