This study describes the current state of the nektonic communities in Terminos Lagoon in relation to the main environmental factors, and documents variations in number of fish species, dominance and abundance, compared to studies performed in 1980. Information on several environmental factors (temperature, salinity, oxygen, pH and transparency) in the Terminos Lagoon between October 1997 and March 1999 allowed the classification of the lagoon into five zones or subsystems. The hydrological characteristics of these subsystems showed spatial differences compared with studies carried out during the 1980s. During the study period, the number of fish species was 105, compared with 154 species reported in the 1980s. Five fish assemblages were identified and appeared to be associated with the five zones or subsystems. Five fish species considered important based on their abundance in the lagoon during the 1980s declined in numbers: pig fish Orthopristis chrysoptera, Atlantic croaker Micropogonias undulates, striped burrfish Chilomycterus schoepfi, spotted seatrout Cynoscion nebulosus and Gulf toadfish Opsanus beta. Six fish species, previously of minor importance, however, were very abundant: star drum Stellifer lanceolatus, Atlantic anchoveta Cetengraulis edentulus, gafftopsail catfish Bagre marinus, sand seatrout Cynoscion arenarius, striped mojarra Eugerres plumieri and ground croaker Bairdiella ronchus. Among the dominant species, the silver croaker Bairdiella chrysoura and the sea bream Archosargus rhomboidalis experienced significant changes in average abundance and distribution patterns. These changes were probably related to the impact of human activities in the Terminos Lagoon and natural variability. # 2005 The Fisheries Society of the British Isles

Cathorops melanopus is the most abundant fish on the west coast of Campeche, Mexico. Its distribution is influenced by water temperature, salinity, and transparency, and it is frequently found in river outlets. To analyze the main biological and ecological patterns of this species, from February 2003 to February 2004 a total of 19,048 specimens were collected using a trawl net at 37 sampling stations along the west coast of Campeche. A subsample was formed of 14,446 randomly selected specimens, and each one was measured and weighed (length range = 35–302 mm, mode = 90 mm; weight range = 0.1–224 g, mode = 6 g). The highest mean abundance values were recorded in May (1.24 ind m–2, 15.31 g m–2, and 12.26 g ind–1), and the lowest in April (0.25 ind m–2, 2.5 g m–2, and 9.9 g ind–1). The parameters of the weight/length model were a = 1 × 10–5 and b = 2.96, with a correlation coefficient of 0.95. The relative condition factor showed a major pulse in July (2.1 × 10–5). The female:male ratio was 1:0.69. Of the 159 females collected, 111 had gonads at maturity stages II and III, and only one was in stage IV. The most common food item was unidentified organic matter, which represented 79% of the total stomach content weight and 92.1% of the encountered food types; the second most abundant food item was crustacean remains (4.8% of the total weight and 10% of the encountered contents). Growth parameters were: L∞ = 317.5 mm, K = 0.45, C = 0.7, WP = 0.16, and t0 = 7.5 × 10–12. Total mortality was 1.22, while natural mortality was 0.65. Recruitment patterns showed a significant pulse between July and August, which together contributed 47.65% of the total number of specimens collected.

Distribution and abundance of fish community in the littoral area of "Los Petenes" Biosphere Reserve, Campeche, Mexico. "Los Petenes" Biosphere Reserve (RBLP) is a critical habitat for many aquatic and terrestrial species. It has the biggest and better conserved seagrass beds, and it represents an important habitat for food, protection and breeding of aquatic organisms, and a temporal refuge for migratory species. The objective of this study was to describe the ichthyofauna diversity in the littoral coastal area of the RBLP, to identify the ecological dominant species, and to analyze the abundance of the fish community and its temporal and spatial changes, and their relationship with some environmental variables. Monthly fish samples were obtained with the aid of trawl nets, from 24 samplings sites distributed along the reserve, between May 2009 and April 2010. The trawl net was operated 288 times and 21 795 individuals with 279.5kg of weight were collected. A total of 46 fish species grouped in 34 genera and 23 families were identified. In a spatial scale, the abundance showed the next ranges: 0.018-0.094ind./m 2 ; 0.249-1.072 g/m 2 and 9.75-19.32g/ind.; the diversity indexes obtained were: H'n=1.46-2.15, J'=0.45-0.71 and D'=2.08-3.92. In a temporal scale, the abundance and diversity ranged between: 0.026-0.066ind./m 2 ; 0.342-0.764g/m 2 and 6.49-22.98g/ind.; H'n=1.76-2.08; J'=0.52-0.64 and D'=3.07-4.18. Eleven dominant species were identified with a representation of the 94.39% in number of individuals, and 89.66% in weight of the total catch. From the total, eight species had economic or commercial importance, especially Lagodon rhomboides and Haemulon plumierii. The cluster analyses identified four fish associations; these results are discussed in order to identify relationships between habitat-species. Finally, the canonical correspondence analysis evidenced an association between H. plumierii with salinity and dissolved solids. The RBLP has high habitat diversity and its fish community has developed strategies to use all the spatial and temporal conditions and to satisfy the needs of their life cycles. Rev. Biol. Trop. 61 (1): 213-227. Epub 2013 March 01.

La Reserva de la Biósfera Los Petenes (RBLP) se localiza en la costa de Campeche, en el Golfo de México. En este ecosistema destacan la fauna nectónica por su abundancia y diversidad, y la amplia cobertura de pastos marinos. El objetivo del presente trabajo fue analizar las asociaciones de los peces dominantes en un marco de variabilidad ambiental temporal (época de secas y época de lluvias) y nictemeral (día y noche). Se realizaron seis campañas de muestreo entre diciembre 2010 y octubre 2011, en un sitio ubicado cerca de Isla Jaina en la región central de la RBLP. Se recolectaron muestras biológicas cada 2 h en un período de 24 h y se realizaron mediciones de temperatura, salinidad, oxígeno disuelto y pH del agua. Se identificaron todos los peces, determinando a las especies dominantes. Las asociaciones interespecíficas y las relaciones entre abundancia y variables ambientales se establecieron mediante técnicas estadísticas de clasificación y ordenación. Se capturaron 10 602 peces con un peso conjunto de 163.62 kg, identificando 44 especies, agrupadas en 33 géneros y 23 familias, de las cuales, 14 resultaron dominantes, destacando la abundancia de Haemulon plumierii. Los dendrogramas específicos construidos por época climática y ciclo nictemeral permitieron identificar tres grupos funcionales. El análisis de correspondencias canónicas para la época de secas destacó relaciones entre salinidad y pH con la abundancia de Eucinostomus gula, Acanthostracion quadricornis y Haemulon aurolineatum. En la época de lluvias, se asoció el oxígeno disuelto con Lagodon rhomboides. No se encontraron diferencias significativas entre las agrupaciones por época climática.

RESUMEN. La comunidad de peces en el sur del golfo de México es abundante y diversa y sus componentes se encuentran afectados por la captura incidental de la pesquería del camarón siete barbas. El presente trabajo describe y analiza los patrones de variación espacial y temporal de la abundancia y diversidad de la comunidad de peces, identificando las especies con dominio ecológico. Los muestreos se realizaron mensualmente entre febrero 2006 y enero 2007 en 37 sitios localizados desde la desembocadura del sistema Grijalva-Usumacinta hasta la desembocadura del sistema Chumpam-Balchacah al interior de la Laguna de Términos, en el estado de Campeche al sur del golfo de México. Se realizaron 444 arrastres experimentales con una red de prueba camaronera y se capturaron 26.386 peces con un peso conjunto de 407,1 kg. Se identificaron 94 especies agrupadas en 65 géneros y 38 familias. La abundancia y diversidad de la comunidad de peces se analizó en escalas espacial y temporal en términos de densidad (ind m ), índice de diversidad (H´n), riqueza de especies (DMg) e índice de equidad (J'). En cuanto a abundancia se distinguieron los altos valores registrados en agosto y septiembre, en sitios cercanos a las desembocaduras de los sistemas Grijalva-Usumacinta y Palizada-Del Este. La especie más importante en términos de abundancia fue el bagre Cathorops melanopus. Los intervalos de variación de los índices de diversidad en escala espacial fueron: H´n = 0,5-2,8 bits; Dmg = 2,6-5,3 sp. ind -1 y J´= 0,1-0,8 bits. En escala temporal los intervalos fueron H´n = 1,8-2,6 bits; Dmg = 5,1-6,7 sp. ind -1 y J´= 0,4-0,6 bits. Se identificaron nueve especies dominantes con 16.840 individuos y un peso conjunto de 278,5 kg, equivalente al 63,8% de la captura total. Palabras clave: abundancia, diversidad, peces, especies dominantes, Campeche, México. Spatial and temporal variability of fish community abundance and diversity off the coast of Campeche, MexicoABSTRACT. The fish community of the southern Gulf of Mexico is abundant and diverse, and its components are affected by the bycatch of the seabob shrimp fishery. The spatial and temporal abundance and diversity patterns of the fish community are described and analyzed in this paper, and the ecologically dominant species are identified. Monthly sampling was carried out from February 2006 to January 2007, at 37 sites located between the mouth of the Grijalva-Usumacinta system to the mouth of the Chumpan-Balchacah system inside the Terminos Lagoon, in the state of Campeche, southern Gulf of Mexico. Using an experimental trawl net, 444 experimental hauls were done, and 26,386 individuals were caught with a joint weight of 407.1 kg. In total, 94 species were identified, grouped in 65 genera and 38 families. The abundance and diversity of the fish community was analyzed on spatial and temporal scales in terms of density (ind m 2 ), biomass (g m 2 ), average weight (g ind -1 ), diversity index (H'n), species richness (Dmg), and evenness (J'). The abundance was high in August and September at sit...