Abstract. During the years of 1989 and 1990, the yield of the commercial fishery for the catarina scallop, Argopecten circularis (Sowerby, 1835), in Magdalena Bay, was 750 million organisms (5186t of muscles), which were gathered by diving at 12–30m depth. This production is the largest registered to date and accounted for 53% of the total Mexican scallop production since 1981. The formation of large beds in that area is a sporadic phenomenon which needs to be studied. In the present paper, a model to explain the formation of such beds is drawn, in which the bentho‐pelagic red crab, Pleuroncodes planipes (Stimpson, 1860), plays a role as primary substrate for the recruitment of the spat and simultaneously is the active transporter of juveniles into the Bay during the winter months of cold years. Apparently exploitable beds are formed only when temperatures of 16°C or lower, are registered deep inside the Bay for at least 2 months. Relating these findings with short and long‐term temperature fluctuations, it seems possible to predict future exploitable stocks in the area.

No sex-specific difference was found in the weight-to-TL relationship between males and females, nor in W or TL separately. By using the inverse von Bertalanffy equation and parameters described by other authors for the same study area, we determined the age range for individuals captured on the basis of their TL. The age ranged from 0 to 39 years in females and from 0 to 21 years in males. Using a logistic model, the mean length at sexual maturity was obtained for 2,532 males (TL = 190 cm). The quarterly distribution of young of the year and 1-year-old juveniles showed that there is a tendency for these sharks to move

We provide an updated list of the caridean shrimp species from the southern region of the Laguna Madre, Tamaulipas, Mexico, along with a key for taxonomic identification. The survey was conducted in 3 sites during 3 temporal seasons. A total of 2,989 specimens were collected belonging to 12 species, 6 genera, and to the following 4 families: Alpheidae, Hippolytidae, Palaemonidae, and Processidae. Hippolytidae was the most abundant family, followed by Palaemonidae, Alpheidae, and Processidae. The hippolytid Hippolyte obliquimanus Dana, 1852, the palaemonids Palaemon floridanus Chace, 1942, and P. northropi (Rankin, 1898), and the alpheid Alpheus cf. packardii Kingsley, 1880 represent new records for the Laguna Madre and selected areas of the Gulf of Mexico.

Resumen Los poliquetos son uno de los grupos más importantes en el bentos desde cualquier punto de vista. Con el presente estudio se tiene el propósito