Dynamics of the Small-Scale Spatial Structure of a Population of the Spider CrabMaja brachydactyla(Decapoda: Majidae)

The use of new multiparametric observatory platforms for the remote monitoring and exploration of deep-sea ecosystems at day-night and seasonal temporal scales

“…Therefore, one may speculate that the hiding behavior of small individuals under normoxic conditions is the result of predation pressure and of avoidance of intraspecific aggression (by large individuals). That explanation is consistent with the significantly negative linear regression between oxygen levels and the intraspecific segregation index (SSL) and with the strongly significant negative cross-correlation in which the 59% of the variability is explained by the oxygen concentration of the Chapter 2 62 SSL.In fact, predation pressure affects the small-scale spatial distribution of benthic macrofauna (Serpetti et al 2013), as the need for protection against predators is a behavioral driver for strong aggregations of epibenthic decapod crustaceans (Corgos et al 2010). In agreement with the aforementioned distribution of small individuals, we could only detect a very narrow patch or "zone of influence" from the spatial autocorrelation analysis.…”

“…Findings similar to our results have been obtained in spider crabs. Adult spider crabs do not display a clear spatial structure, whereas small individuals are found in strong aggregations (Corgos et al 2010).…”

Factors influencing successful settlement and metamorphosis of the common spider crab Maja brachydactyla Balss, 1922 (Brachyura: Majidae): Impacts of larval density, adult exudates and different substrates

“…Potentially, this may reflect the observation that adult and early juveniles in the wild do not share the same habitats as has been observed for Callinectes sapidus or Carcinus maenas (Forward Jr et al, 1994;Zeng et al, 1997). Field studies have indicated that adult and juvenile M. brachydactyla are segregated spatially (Corgos et al, 2010;Corgos et al, 2011;Le Foll, 1993). Corgos et al (2011) postulated a scenario where juvenile recruitment occurs in shallow coastal benthic areas of less than 5 meters depth, following which post-metamorphic individuals migrate to depths between 5 and 15 meters before migrating to greater depths when the adult stage is reached.…”

“…Moreover, juveniles and adults are segregated spatially, with juveniles usually inhabiting bottoms from 0 to 30 meters depth while adults migrate annually from 50 -200 meters depth to less than 30 meters depth (Corgos et al, 2010;Corgos et al, 2011;Le Foll, 1993). Currently, natural settlement and recruitment sites have not been defined nor has the habitat required by early juvenile stages (< 50 mm) (Corgos et al, 2011;Le Foll, 1993).…”