MEPS 491:137-151 (2013)  -  DOI: https://doi.org/10.3354/meps10456

ABSTRACT: Transplantation of mussels Mytilus galloprovincialis to Wellington Harbour and Cook Strait (central New Zealand) was carried out to test for bottom-up control (food limitation) of intertidal community structure and scarcity of mussels. Analysis of water-column variables revealed that mean turbidity and chlorophyll a concentrations were 3 and 10 times higher, respectively, in Wellington Harbour than in Cook Strait. The responses of transplanted mussels reflected the water-column properties: mortality of Wellington Harbour mussels was very low whereas mortality of Cook Strait mussels was significantly greater, and all components of shell growth and soft tissue condition were higher for Wellington Harbour than Cook Strait mussels. These results are consistent with bottom-up control of mussel abundance, as mediated by feeding activity, body condition and energy balance. The results demonstrate how pronounced differences in localised coastal conditions may influence temperate rocky intertidal community structure on spatial scales of hundreds of metres, and how this influence may explain differences in community composition on spatial scales of many kilometres.

KEY WORDS: Mytilus galloprovincialis · Food limitation · Bottom-up control · Coastal processes · Growth · Condition index · Mortality