NEW APPROACHES TO THE BEHAVIORAL ECOLOGY OF DECAPOD CRUSTACEANS USINGTELEMETRY AND ELECTRONIC TAGS

Decapod crustaceans have complex life histories and behaviour ire aspe cts such as foraging, mating and reproduction, moulting and growth, ha bitat selection and migration. New technologies have enabled us to use an individual, field-based approach to analyze these problems, althou gh they have been less developed in decapods than in marine vertebrate s. These new possibilities are discussed here mainly from a biological point of view. There is a brief review of previous applications of te lemetry to analyze habitat selection, foraging behaviour, energetics, moulting site selection and migrations in decapods, and two case studi es are discussed in more detail. The first one refers to the study of differences in habitat use and movement patterns in juveniles and adul ts of coastal species that show ontogenetic habitat shifts, related to differences in selective pressures affecting both life history stages (predation risk, and growth and reproduction optimization). The secon d case study is dedicated to the migratory patterns in spider crabs co mbining telemetry and electronic tags. Operational limitations in trac king make it impossible to get detailed information on movement patter ns during migration, which in turn involve an important bathymetric gr adient and a change in the oceanographic environment (mainly temperatu re). Monitoring depth and temperature in the immediate habitat of the animals, using electronic data storage tags recovered by the fishery, allow for movement patterns to be modeled using supplementary informat ion on the topography and hydrography of the study area. This approach is being tested using both telemetry and electronic tags simultaneous ly.