Recursos Marinos y Pesquerías

Distribution and habitat use in coastal decapods [Working paper]

10/05/05 ,

A Pallas, B García-Calvo, A Corgos, C Bernárdez, J
Freire. Inter-specific comparative analysis of distribution and
habitat use patterns of benthic decapod crustaceans in shallow waters. Working paper (v.1, May 2005). [pdf]

ABSTRACT: Coastal areas have been widely considered as
nurseries for many marine species. New approaches to this concept take into
account interactions among environmental variables and ecological variations
related to geographical location, as well as complex life cycles of marine
invertebrates. We present a comparative approach to assess the relevance of
environmental variables on the determination of patterns of distribution and
habitat use of benthic decapod species in coastal areas. We hypothesize that
this approach allows us to infer processes originating these patterns and to
identify the main habitat use models. An intensive fine-grain sampling design
was used to take into account the environmental gradients occurring at
different spatial scales (defined by substrate type, depth, exposure and
geographical location) in a temperate oceanic bay (Ria de A Coruña, Spain). A
high proportion of juveniles were found in most populations, but the results do
not allow us to generalize the idea of coastal areas as potential nurseries,
except for few species with a marked spatial segregation between juveniles and
adults. Larval transport seems to be the main process regulating mesoscale
distribution patterns, while microscale distribution responds to a complex interaction
among different processes, i. e. habitat selection at settlement, differential
mortality among habitats, post-settlement dispersal and ontogenetic habitat
shifts. Sandy substrates showed low-diversity communities dominated by hermit
crabs. In rocky bottoms, variability in spatial patterns was mostly related to
substrate type and geographical location. Caridean shrimps showed higher
densities on flat rock surfaces, with similar juvenile and adult patterns.
Anomuran species occurred mainly on cobbles. Distribution patterns of
brachyurans varied among species, but did not change greatly from juveniles to
adults.