Ten monthly collections, distributed among three seasons, were taken from July 2000 to June 2001 in the Alvarado lagoonal system, Veracruz, Mexico. Variables measured in situ included dissolved oxygen, salinity, and water temperature. Water samples were collected to determine concentrations of ammonium, nitrates, nitrites, orthophosphates, total phosphorus and chlorophyll a. Collections representing the rainy season were taken in September and October, those for the nortes season were taken in November, December, and January, and dry season collections were taken during February, March, May June, and July. There was seasonal and spatial variation in nutrient concentrations, and they were related to the discharge of the rivers; concentrations increased during the rainy and nortes seasons. Other factors affecting water quality included the constant discharge of organic materials into the system, resuspension of sediments during the nortes season and the biological activity within the system that assimilated the nutrients in the water. The Alvarado lagoonal system has three separate zones based on physicochemical characteristics; Camaronera Lagoon, Buen Pais Lagoon and the urban zone of Alvarado Lagoon, and the river zone in Alvarado Lagoon. RESUMEN Se realizaron diez muestreos durante el periodo comprendido entre Julio de 2000 a Junio de 2001, distribuidos a lo largo de tres estaciones climáticas, en el sistema lagunar de Alvarado, Veracruz, México. Los parámetros que fueron registrados in situ incluyendo oxígeno disuelto, salinidad y temperatura de agua. Al mismo tiempo se colectaron muestras de agua para determinar en laboratorio las concentraciones de amonio, nitratos, nitritos, ortofosfatos, fósforo total y clorofila a. Los meses de colecta que abarcaron las temporada de lluvias fueron tomadas en Julio, Septiembre y Octubre, para Nortes Noviembre, Diciembre, y Enero, y por último, la temporada de secas que correspondieron los muestreos de Febrero, Marzo, Mayo, y Junio. Los nutrientes presentan una variación espaciotemporal presentando relación con: la descarga de los ríos, incrementándose su concentración durante la temporada de lluvias y Nortes; las constantes descargas de agua provenientes de diversas actividades humanas, como son la agricultura y los asentamientos humanos; la resuspensión de los sedimentos durante la temporada de Nortes; y la gran actividad biológica de estaos sistemas que permiten la rápida transformación de la materia orgánica en nutrientes. El sistema lagunar de Alvarado presenta tres zonas diferentes basadas en sus características fisicoquímicas:
Abstract.-The brown shrimp (Penaeus aztecus) fishery is the most important in the Gulf of Mexico. This fishery takes non-target species or by-catch fauna, mainly teleost fishes, which are incidentally captured. Some of the by-catch species has commercial use and the rest of them are discarded. Therefore, it is important to describe the composition of the discarded fauna, to determine the impacts under the ecosystem approach. Discarding catch of shrimp trawls carried out in 2013 on the continental shelf off the State of Veracruz in different depth intervals (22-46 and > 46 m) was analyzed. For each trawl, the shrimp catch, the commercial by-catch and the discarding were recorded and the catch ratios respect to shrimp, were obtained. A discard sample was taken and the species were identified, the total length was taken and the ecological parameters were calculated. The non-parametric multiple dimensional scaling test was performed. A total of 7,178 fishes were collected from 34 families, 46 genera and 51 species. The ratio of commercial species by-catch: shrimp and discard: shrimp was 15.41:1 and 40:1 kg, respectively. The species with high relative dominance were Citharichthys macrops, Synodus foetens, Diplectrum bivittatum, Rhomboplites aurorubens and Upeneus parvus. The species with greater importance index were C. macrops, S. foetens, and D. bivittatum. The 43.14% of the discarded species are used as food and 7.84% as bait. The maximum diversity (H´) was 3.76 bits ind -1 and the trophic level was 4.31. The study of discard composition is a basis to assess the impact generated by the shrimp trawlers and provides guidelines for identify changes in the community structure. Key words: Discard, fishes, shrimp, Alvarado, VeracruzResumen.-La pesquería del camarón café Penaeus aztecus es la más importante en el Golfo de México. En esta pesquería se capturan de manera incidental especies no objetivo compuestas mayormente por peces teleósteos. Es importante describir la composición del descarte, para determinar el impacto de los arrastres camaroneros bajo un enfoque ecosistémico. Se analizó la captura de descarte de arrastres camaroneros realizados en 2013 en la plataforma continental del Estado de Veracruz en 22-46 y >46 m de profundidad. Para cada arrastre se registró la captura de camarón, fauna de acompañamiento comercial, descarte y fauna de acompañamiento. Se tomó una muestra del descarte, se identificaron las especies y se calcularon los parámetros ecológicos de la muestra. Se realizó una prueba de escalamiento dimensional múltiple no paramétrica. De 87 lances de pesca, se analizaron 7.178 organismos correspondientes a 34 familias, 46 géneros y 51 especies. Las especies con mayor dominancia relativa y mayor valor del índice de importancia fueron: Citharichthys macrops, Synodus foetens, Diplectrum bivittatum, Rhomboplites aurorubens y Upeneus parvus. Un alto porcentaje de las especies de descarte (43,14%) presentan uso potencial de alimento y 7,84% carnada. En promedio, la relación Fauna de Acompañamiento Comercia...
The fish assemblages of Alvarado Lagoon Estuary (a complex of coastal lagoons in the state of Veracruz, Mexico) have been surveyed intermittently by different researchers over the last 40 years. Assessing longterm trends in fish assemblage composition for this ecosystem is problematic due to differences in sampling efforts among the survey periods (
The first exotic specimen of Penaeus monodon (tiger shrimp) was recorded in the most important shrimp fishing ground of Veracruz, Mexico. In February 2014, one individual of 29 cm LT was collected at 90 m depth off South-central coast of Veracruz at 22 Km northwest of Coatzacoalcos port and 150 Km southeast from Alvarado. The tiger shrimp was introduced in Cuba in 1986 for cultivation. In 2013 the presence of nine individuals in the Campeche coast was reported. This recording evidence the movement of P. monodon into the Gulf of Mexico which is a concern because of their possible impact on local shrimp populations and their ecosystem.
In the present study, we reared juvenile dark crabs, Callinectes rathbunae under laboratory conditions. We determined growth rate, increase in carapace width, moult consumption, regeneration of appendages, and survival. The crabs were collected in March 2004 from the Alvarado Lagoon System in the state of Veracruz, Mexico. Crabs were transported to the laboratory and acclimated to 5 and 15 psu and a temperature of 25 ± 1 • C. Growth rate was determined by the difference in size at the time interval between the pre-moult and moult stages. Survival was assessed by counting the juvenile crabs during rearing, moult consumption was determined after 24 hours, and regeneration of appendages at the next moult. The size of juveniles ranged from 1.7 to 6.4 cm. Results revealed that carapace increase was greater at 15 psu, being 35.29% for the 1.7-2.8 cm size range. The mean growth rate at 5 psu was 0.33 ± 0.07 mm/day and 0.76 ± 0.12 mm/day at 15 psu. Moult consumption was 50%. A 100% regeneration of appendages was observed after moulting. Survival was best at 15 psu, with 78.31%. RESUMENEn el presente estudio se realizó el cultivo de cangrejos juveniles de Callinectes rathbunae en condiciones de laboratorio. Se determinó la tasa de crecimiento, el incremento en el ancho del caparazón, el consumo de la muda, la regeneración de apéndices y la sobrevivencia. La colecta se realizó en Marzo de 2004 en el Sistema lagunar de Alvarado, Veracruz, México. Los cangrejos fueron transportados al laboratorio y aclimatados a 5 y 15 ups y temperatura de 25 ± 1 • C. La tasa de crecimiento se determinó por la diferencia de talla y el intervalo de tiempo transcurrido entre la premuda y la postmuda, la sobrevivencia por el conteo de cangrejos juveniles durante el tiempo de cultivo, el consumo de la muda después de 24 h y la regeneración de los apéndices a la siguiente muda. El intervalo de talla de los juveniles fue de 1,7 a 6,4 cm. Los resultados mostraron que el 2 ) Crustaceana 80 (2): 161-170 Also available online: www.brill.nl/cr 162 SERGIO CHÁZARO-OLVERA ET AL.incremento en el ancho del caparazón fue mayor en una salinidad de 15 ups con el 35. 29% en el intervalo de talla de 1,7 a 2,8 cm. Las tasa de crecimiento promedio a 5 ups fue de 0,33 ± 0,07 mm/día y a 15 ups fue de 0,76 ± 0,12 mm/ día. El consumo de muda fue del 50%. Se observó un 100% de regeneración de apéndices después de la muda. El porcentaje de sobrevivencia fue mayor a 15 ups con el 78,31%.
This study presents the changes in the agonistic behavior of the crab Callinectes rathbunae parasitized by Loxothylacus texanus, collected in Alvarado Lagoon, Mexico. Alive parasitized crabs were observed in the laboratory for their behavior. Hepatopancreas of the parasitized crabs were fixed for examination. Both crabs with virgin and mature externa were monitored, and their degree of aggressiveness compared. The aggressiveness of the parasitized crabs decreases according to the parasite development. A possible relation with behavior and hepatopancreas infestation is given. In this study it is observed that the crabs with virgin externa are more aggressive than organisms with mature externa. Also, the agonistic behavior of the host decreases according to the development of the parasite. This is the first report where behavioral changes of parasitized crabs caused by a rhizocephalan, degree of development of the parasite and hepatopancreas atrophy are described.
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
<p>The lionfish <em>Pterois volitans</em>, is an predator in coral system, whose diet is composed of small fish and crustaceans, impacting species of ecological and commercial importance. <em>P. volitans</em> is an exotic species in the Gulf of Mexico with high colonization capacity. The present study describes its population structure, type of growth and trophic dynamics. 97 organisms of the PNSAV were obtained, 64 females (185±6,7 mm LP; 257,6±27,8 g) and 22 males (183±15,8 mm of LP; 273,5±62,6 g). Whit the Battacharya model, four size classes were obtained for females (15,3; 25,3; 28,2, and 31,8 cm) and six for males (9,87; 17,95; 22,95; 26,95; 30,95 and 33,95), being the size class 1 for both sexes the most abundant. The length-weight relationship was of the potential type (r<sup>2</sup>=0,9643, b=3,1574 females, and r<sup>2</sup>=0,9843 and b=3,1089 males), and growth of allometric type for both sexes. The growth model that best adjusted to the data was that of Gompertz, (L<sub>∞</sub>=324 mm, k=0,99, t<sub>0</sub>=0,694 females and L<sub>00</sub>=379,4, k=0,468, t<sub>0</sub>=0,719 males). The families of fish identified in the stomach contents were Ophididae, Serranidae, Haemulidae, Pomacentridae, Beloniidae, Achiridae, and crustaceans Portunidae, Penaeidae, Squillida<em>e</em> and Diogenidae. Being <em>Haemulon aurolineatum</em> (Haemulidae) and <em>Xiphopenaeus kroyeri</em> (Penaeidae) the most important prey. The presence of lionfish in the PNSAV is recent, so the information presented in this research will allow us to understand its population dynamics and its adaptation to the PNSAV, contributing to its management and control.</p>
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