%0 Journal Article 
%A Almeida, M.J.
%A González Gordillo, Juan Ignacio
%A Flores, A.V.V.
%A Queiroga, H.
%T Cannibalism, post-settlement growth rate and size refuge in a recruitment-limited population of the shore crab Carcinus maenas.
%D 2011
%U http://hdl.handle.net/10498/16692
%X Previous studies on intra-specific interactions among green shore crabs have been undertaken in very large
populations, in which individuals concentrate at high densities in physically complex substrates. Under
such conditions, cannibalism and interference competition often override initial density patterns delivered
by larval supply. In this study, we focused on a Carcinus maenas population receiving a low supply of settlers.
We reported crab abundance in habitats of different physical structure, and measured cannibalistic interactions,
in different substrates, at a prey density expected only after a major recruitment event. Different predator
and prey sizes were used to verify if juveniles froma critical range attain a size refugewhen coexistingwith subadults,
which are still commonly found in the nursery habitat. Virtually no juvenile shore crabs were found on
sandy habitats, and differences between sparsely and densely vegetated cover were only detected shortly after
a settlement pulse, indicating that nursery habitats are under their carrying capacity most of the time. Even
under extreme high densities, cannibalism on juveniles of 10 mm carapace width (CW) remained undetected,
and predation on crabs half this sizewas only significant in lowand mediumZostera cover,when larger predators
(20–25 mmCW)were included in experimental plots. The allometricmodel predicted the non-linear decrease of
predation rate as a function of relative prey size, with a nearly asymptotic value of one prey consumed each 5 d
by one predator in a square metre, when relative prey size attains 0.6. Such a relationship is expected for ‘cruising’
predators which rely on encounter rate. Growth estimates obtained using time series of the catch of distinct
juvenile stages in artificial collectors indicated that crabs surviving 50 d after settlement have attained a size refuge
from predation by larger conspecifics
%K Habitat structure
%K Juvenile growth
%K Nursery habitat
%K Predation
%K Relative prey size
%K Shore crab
%~ Universidad de Cádiz