Cannibalism, post-settlement growth rate and size refuge in a recruitment-limited population of the shore crab Carcinus maenas

Abstract

M.J. Almeida), nacho.gonzalez@uca.es (J.I. González-Gordillo), guca@usp.br (A.A.V. Flores), henrique.queiroga@ua.pt (H. Queiroga). 0022-0981/$see front matter

Hide and seek: habitat-mediated interactions between European green crabs and native mud crabs in Atlantic Canada

“…As addressed in detail below, it is also plausible that habitat and the occurrence of green crab cannibalism events (Moksnes 2004;Almeida et al 2011) play a role in these interactions, and that was the reason to assess both factors in our experiments.…”

Conspecific cues affect stage-specific molting frequency, survival, and claw morphology of early juvenile stages of the shore crab Carcinus maenas

“…Direct effects of conspecific cues on overall fitness parameters are apparently restricted to megalopae and the first two juvenile stages. Faster metamorphosis and slightly higher growth rates in cued crabs, made possible by a shorter intermolt period at stage 2, may respectively allow settling on appropriate habitat (e.g., Forward et al, 2001;Simith & Diele, 2008) and reaching a size refuge from predation first (e.g., Moksnes, 2004;Almeida et al, 2011). Also, higher molting frequency allow enhanced allometric growth, and thus faster development of morphological attributes of putative adaptive significance, such as the case made here on alternative claw shape.…”

“…Morphological defenses developed after persistent exposure to predators (e.g., Lively, 1986;Trussell, 2000) are just one kind of a wide variety of chemically induced responses (Agrawal, 2001). In species prone to cannibalistic interactions, such as Carcinus maenas (L.), where predators are 3-5 times larger than their prey (Moksnes et al, 1998;Moksness, 2002;Almeida et al, 2011), morphological change of defensive organs, i.e., their chelipeds, would hardly deter any attacks. However, chelipeds are also used for handling food (Hughes & Elner, 1979;Mariappan et al, 2000).…”

“…Because inter-cohort cannibalism in juvenile C. maenas is frequent (Moksnes, 2004;Almeida et al, 2011), decreased growth in early recruits when exposed to adult cues could indicate reduced foraging activity, which probably imply in reduced predation risk in natural conditions. In an opposite strategy, enhanced growth will allow cued juveniles to attain a size refuge from predation earlier, even at the expense of higher mortality owing to excessive metabolic demand (Bayne, 2000;Mangel & Munch, 2005).…”

PopulationDynamics of Green Crabs (Carcinus maenas) -- A Review

“…Megalopae settle out of the plankton in protected areas of the intertidal zone. Juvenile crabs prefer gravel or cobble areas or mussel beds where they can shelter under rocks and seaweed to avoid predation and cannibalism [29,[61][62][63][64][65][66][67][68][69][70][71]. As crabs age they move into lower intertidal and subtidal zones, where they are able to shelter under rocks and boulders and macroalgae in rocky areas and amidst eelgrass and fouling communities or in burrows along Spartina banks in estuaries.…”