The Effect of Climate Variability on Gray Whales (Eschrichtius robustus) within Their Wintering Areas.

The environmental conditions of the breeding and feeding grounds of the gray whale (Eschrichtius robustus) fluctuates at inter-annual scales in response to regional and basin climate patterns. Thus, the goals of this study were to assess if there are any relationships between summer sea ice on their feeding ground and counts of gray whale mother-calf (MC) pairs at Ojo de Liebre Lagoon (OLL); and if El Niño Southern Oscillation (ENSO) influences the winter distribution of gray whales MC pairs in the three primary breeding lagoons of OLL, San Ignacio Lagoon (SIL) and Santo Domingo Channel north of Bahia Magdalena (SDCh). Maximum February counts of MC pairs were compared with the length of the open-water season at the Bering Sea during the previous year.

Statistical inference for extinction rates based on last sightings.

Rates of extinction can be estimated from sighting records and are assumed to be implicitly constant by many data analysis methods. However, historical sightings are scarce. Frequently, the only information available for inferring extinction is the date of the last sighting.

[Impact of surface temperature and salinity on the recruiting of the pink shrimp Farfantepenaeus duorarum (Decapoda: Penaeidae), in Sonda de Campeche, Gulf of Mexico].

We studied the long term effects of two environmental variables, salinity and surface temperature, on the pink shrimp (Farfantepenaeus duorarum) population in the southern Gulf of Mexico, considering the relationship between recruiting and the concurrent shrimp stock depletion of the last two decades. Our data were collected from 1969 to 1991. Recruitment has been clearly declining, particularly in the 1970s, with an accentuated drop since the 1980s.