Reproductive cycle of the mollusk Atrina maura (Pterioidea: Pinnidae) in a coastal lagoon system of the Mexican South Pacific. From February 1997 to February 1998, random samples of the mollusk Atrina maura were collected on a monthly basis from the Corralero-Alotengo lagoon system, Oaxaca, Mexico. The soft parts were separated from the valve, washed in situ, and placed in a Davison solution. The gonadosomatic index (GSi) and the muscle yield index (MYi) were measured, and the reproductive cycle was characterized by histological cuts. A. maura has two important reproductive periods, one from April to July and another from October to November; there is a resting period from August to September. The reproductive cycle has a direct relationship with the GSi and a reverse relationship with the MYi. There was evidence of a close relationship of the spawning and post-spawning periods with the water temperature (R = 0.991, p ≥ 0.002). Females dominate numerically throughout the year, but the difference is significant (χ²: p≥ 0.05) only in November. Rev. Biol.

RESUMENSe predice numéricamente la circulación inducida por la componente M2 de la marea y el viento en Bahía de los Angeles. La amplitud y la fase de la marea son prácticamente iguales en toda la bahía, las corrientes de marea son del orden de 3 cm/s y las residuales de la marea de 0.5 cm/s. En cambio las corrientes inducidas por el viento alcanzan hasta 25 cm/s en las áreas de intensificación.La configuración de la costa y la batimetría dominan las principales características de la circulación. Para cualquier dirección del viento dominante, se presenta un fuerte intercambio con el exterior, y un giro persistente en la ensenada La Gringa y con la parte central de la bahía. Las zonas de flujo más intenso son el canal sur y la zona costera al sur de la ensenada La Gringa. ABSTRACTThe circulation induced by the M2 component of the tide and wind at Bahía de los Angeles was predicted. The tide amplitude and the phase are practically the same at the bay, the tide currents values are 3 cm/s and the tide residuals 0.5 cm/s. Otherwise, the induced currents by the wind reach until 25 cm/s at the intensification areas. The coast configuration and the bathymetry dominate the main characteristics of the circulation. There is a strong interchange with the exterior to any dominant direction of the wind, and a persistent gyre at the inlet of La Gringa and at the middle of the bay. The most intenses flux zones are the southern channel and the coastal zone to the South of La Gringa inlet. INTRODUCCION 39

For this, fishery catches information was obtained from the artisanal fleet, at six landing sites in the Gulf, and the sex ratio, fork length (FL) and the catch per unit effort (CPUE) were estimated. From all sampling sites, a total of 3 494 females, and 3 877 males were obtained, and dolphinfish size as fork length (FL) ranged from 20.5 to 152cm. Fish size ranged from 25.5 to 148cm furcal length (FL) in males, and 20.5 to 129cm FL in females. The sex ratio (males:females) was 1:1, except in April-May (1:1.5, p<0.05) and November (1:0.5, p<0.05). The sex ratio at different size classes showed a significant bias towards females at smaller sizes (<75cm FL), whereas the males were predominant in larger size classes (>100cm FL). The size structure was bimodal, with a variation in the size average; the modes were defined as the small group (FL=50-55cm) and the large size group (FL=100-110cm). The CPUE showed seasonal changes: values were high for the November-December period, and values were lower for July-August. The seasonal and inter annual variation in the abundance of dolphinfish is probably related to a pre-spawning migration in close relation to the rain-drought regime characteristic of the region, and the associated wind upwelling season of "Tehuanos" in the Gulf of Tehuantepec. Rev. Biol. Trop. 62 (2): 611-626. Epub 2014 June 01.

No abstract

En el Sistema Lagunar Huave, la explotación y la distribución de la captura artesanal de camarón resultaron afectadas por diferencias en la calidad hidrológica (temperatura superficial, salinidad, oxígeno disuelto y turbidez) y la pérdida en la cobertura de manglar. Las mejores condiciones hidrológicas con extensas áreas de manglar fueron observadas en las lagunas Oriental y Occidental, donde el 97% de la captura artesanal de camarón fue obtenida. Las peores condiciones hidrológicas con escasas áreas de manglar fueron registradas al interior (0.35%) y en la entrada (0.85%) del Mar Tileme, donde la captura artesanal de camarón fue escasa, registrando una tasa de mortalidad natural de 0.82 mensual. El período analizado fue de 1999 al 2007, pero de acuerdo con los antecedentes bibliográficos, el reclutamiento marino de camarones juveniles en este sistema lagunar comenzó a descender en el Golfo de Tehuantepec, durante los años ochenta. La presión por pesca fue modificada por las condiciones ambientales imperantes en cada sección del cuerpo lagunar, esta fue “muy baja” en el Mar Tileme, “alta” en las lagunas Oriental y Occidental y “baja” en la Laguna Inferior.Abstract In the Huave Lagoon System, the artisanal exploitation and distribution of shrimp were affected by the loss of hydrological quality (surface temperature, salinity, dissolved oxygenate and turbidity) and mangrove cover. The best hydrological conditions with extensive mangrove areas were observed in the Oriental and Occidental Lagoons, where 97% of artisanal shrimp catches was obtained. The worst hydrological conditions with little mangrove area were recorded within (0.35%) and in the entrance (0.85%) of the Mar Tileme Lagoon, where artisanal shrimp catches were low, recording a natural mortality rate of 0.80 per month. The period analyzed was from 1999 to 2007; however, according to the literature, the marine recruitment of juvenile shrimp in this lagoon system began to decline in the Gulf of Tehuantepec during 1980s. Fishing pressure was modified by the prevailing environmental conditions in each lagoon section. This pressure was “very low” in the Mar Tileme Lagoon, “high” in the Oriental and Occidental Lagoons, and “low” in the Inferior Lagoon.