Interacciones tróficas de las seis especies de peces más abundantes en la pesquería artesanal en dos bahías del Pacífico Central Mexicano

Trophic interactions of the six most abundant fish species in the artisanal fishery in two bays, central Mexican Pacific. We surveyed the trophic components in six species of Bahía de Navidad and Bahía de Chamela: Microlepidotus brevipinnis, Caranx caballus, Haemulon flaviguttatum, Lutjanus guttatus, L. argentiventris and Mulloidichthys dentatus. Two main seasonal periods were considered: 1) North Equatorial Counter Current NECC period influence (T1) and 2) California Current CC period influence (T2). In Bahía de Navidad 78 prey taxa were identified in the stomachs. From July to December (T1), 64 prey taxa were found, and from January to June (T2), 45 prey items. In Bahía de Chamela 93 prey items were identified; 74 during T1 and 60 during T2. The highest prey number was found in the stomachs of M. dentatus during T1 in Bahía de Navidad and the lowest prey number (7) was recorded in H. flaviguttatum in Bahía de Navidad in the same period. Crustaceans were the most frequently recorded prey items, followed by fishes, mollusks, polychaetes, and echinoderms in both seasonal periods and sites. The six fish species studied are considered as specialist feeders due the low values of the niche breadth index. There was little similarity among the diets. Rev. Biol. Trop. 58 (1): 383-397. Epub 2010 March 01.

Se analizaron los componentes tróficos de las seis especies de peces más importantes en la captura de la pesquería artesanal en las Bahía de Navidad y Chamela, ubicadas en la costa de Jalisco, México. Las especies estudiadas fueron Microlepidotus brevipinnis, Caranx caballus, Haemulon flaviguttatum, Lutjanus guttatus, Lutjanus argentiventris y Mulloidichthys dentatus. Se consideraron dos periodos de estudio de acuerdo a las pautas hidroclimáticas y los patrones de producción biológica en la zona: periodo de influencia de la Contracorriente Norecuatorial (T1), y periodo de influencia de la Corriente de California (T2). En Bahía de Navidad se identificaron 78 presas en total para las seis especies. En el periodo comprendido entre julio y diciembre (T1) se identificaron 64 presas y 45 de enero a junio (T2). En Bahía de Chamela se identificaron 93 presas, encontrando 74 presas en el periodo T1 y 60 presas para el periodo T2. El mayor número de presas se encontró en M. dentatus con 34 presas en el periodo T1 de Bahía de Chamela y el menor número fue en H. flaviguttatum en T1 de Bahía de Navidad con solo 7 presas. Los crustáceos fueron las presas de mayor presencia en la dieta, seguidos por peces, moluscos, poliquetos y equinodermos, en ambos periodos y sitios de muestreo. Las seis especies analizadas se consideran como especialistas, dados los bajos valores del índice de amplitud de nicho en ambos periodos y sitios de muestreo.

The fish species composition and variation of catch from the small-scale gillnet fishery before, during and after the 1997-1998 ENSO event, central Mexican Pacific

In the tropical and subtropical coastal zone, were highly diverse fish communities occur, it is important to study the small scale fisheries exploiting these communities. For this study, 219 fishing days were carried out in Bahia de Navidad, Jalisco, Mexico. Four gillnets with different mesh sizes (76.2, 88.9, 101.6 and 114.3 mm) were used for the fishing operations, from April 1994 to March 1995 and from January 1998 to December 2000. A total of 26126 organisms weighting 11680 kg were caught. One hundred and eighty three species belonging to 57 families and 19 orders were identified. Ten species accumulated more than 60% of the total abundance and biomass, the remaining species (173) individually contributed with less than 2% of the total abundance and biomass. The most important species in the catch were Microlepidotus brevipinnis, Caranx caballus, Haemulon flaviguttatum, Scomberomorus sierra, C. caninus, C. sexfjasciatus, Lutjanus guttatus and L. argentiventris. The catch per unit of effort showed a large variation during the study, both in number and biomass. On average, 110 fishes and 48.5 kg fishing day(-1) were caught. The maximum values were recorded during January and October 1998 (250 fishes and 100 kg fishing day(-1)), and the minimum values were recorded during September and November 1994 (25 org. and 10 kg fishing day(-1)). The total abundance and biomass was lower during the 1994-95 period (F=6.16, 8.32, P<0.05). There were statistically significant differences among the annual catch from each gillnet. All the environmental changes caused by the ENSO event had ecological and economic effects that can be rated from moderate to severe.

Se llevaron a cabo 219 días de pesca experimental en la Bahía de Navidad, Jalisco, México. Se utilizaron cuatro redes de enmalle de diferente luz de malla (76.2, 88.9, 101.6 and 114.3 mm de luz de malla), de abril de 1994 a marzo de 1995 y de enero de 1998 a diciembre de 2000. En total se capturaron 26126 organismos que pesaron 11680 kg. Fueron identificadas 183 especies pertenecientes a 57 familias y 19 órdenes. Diez especies acumularon más del 60% de la abundancia y biomasa total, el resto de las especies (173) individualmente aportaron menos del 2% de la abundancia y biomasa total. Las especies más importantes en la captura fueron Microlepidotus brevipinnis, Caranx caballus, Haemulon flaviguttatum, Scomberomorus sierra, C. caninus, C. sexfasciatus, Lutjanus guttatus y L. argentiventris. La captura por unidad de esfuerzo mostró una gran variación durante todo el periodo de estudio, tanto en número de organismos como en biomasa. En promedio se capturaron 110 organismos/día de pesca (48.5 kg/día de pesca). Los valores máximos se registraron durante enero y octubre de 1998 (250 peces y 100 kg por día de pesca), y el mínimo se registró durante septiembre y noviembre de 1994 (25 organismos y 10 kg por día de pesca). La abundancia y biomasa total fue menor durante el periodo 1994-1995 (F=6.16, 8.32, P<0.05). Se encontraron diferencias estadísticamente significativas entre la captura anual de las diferentes redes. Los cambios ambientales provocados por el evento ENOS tuvo efectos que pudieran considerarse de moderados a severos, tanto ecológicos como económicos.

Ictiofauna de la pesquería ribereña en Bahía de Navidad, Jalisco, México, asociada al evento El Niño 1997-1998 / Ichthyofauna fisheries in BahÝa de Navidad, Jalisco, Mexico, associated to the El Niño event 1997-1998

The ichthyofauna fished in BahÝa de Navidad, Jalisco, Mexico in the Central Pacific was surveyed during 1998. Six thousand nine hundred and fourty-four organisms of 130 species were caught which weighted 3,231 kg. Nearly 30 of the species belonged to Carangidae. Haemulidae and Sciaenidae. The most important species in number and biomass were Microlepidotus brevipinnins, Caranx caninus and C. caballus. Species number, abundance and biomass fluctuated during the year. The largest number of species was caught in June (61), the minimum in March (33). January had the maximum abundance (1,397 organisms), while the minimum was obtained during August (251). The maximum biomass values were from January (556.5 kg), and the lowest from August (114.7 kg). Eighteen species accumulated 87 of the total abundance, while 20 species represented 86.3 of the biomass. There were large in differences species number, abundance and biomass nets of different mesh size.