Background & Approach
Our current study is focusing on two species of marine crabs: the intertidal/ estuarine crab, Carcinus maenas and the subtidal edible crab, Cancer pagurus. We are exposing crabs for 12 months to a reduction in salinity and an elevation in pCO2, either alone or in combination to mimic the conditions that they might experience in the near future i.e. 2100.
C. maenas is remarkably tolerant of a range of environments,has a wide geographical distribution and is highly invasive outside of Europe. It can compete and displace native crab species, is an important predator of molluscs and can influence community diversity. C. maenas is capable of regulating the ion concentrations of its body fluids down to an external salinity of 30% seawater by increasing activity levels of the key ion transporting enzymes.
C. pagurus is a shallow water species inhabiting European rocky shores from tidal levels (juveniles) down to 50-100m (adults). It is commercially important in the UK accounting for for £1 million of shellfish landings per annum in Wales alone. Despite its commercial value, relatively little is known about its physiology apart from the fact that it is conforms to changes in salinity, and the juveniles are better at surviving in dilute seawater rather than the adults.
Our overall aim is to more fully understand the interactions between environmental change, physiological homeostasis, and the associated energetic restraints and trade-offs. We are interested to see whether compensation for environmental change in the most tolerant species may compromise other energy demanding processes, such as immune performance, reproduction and growth, all of which may lead to population decline and changes in community interactions and structure. Studies are being conducted at different stages of development from larvae to juvenile crabs.