|Increased gonad ratio in the blue mussel, Mytilus edulis, exposed to starfish predators|
Reimer, O. (1999). Increased gonad ratio in the blue mussel, Mytilus edulis, exposed to starfish predators. Aquat. Ecol. 33(2): 185-192
In: Aquatic Ecology. Springer: Dordrecht; London; Boston. ISSN 1386-2588, more
Asterias rubens Linnaeus, 1758 [WoRMS]; Mytilus edulis Linnaeus, 1758 [WoRMS]
The presence of invertebrate predators can induce morphological, physiological, and behavioural changes in sessile marine prey species. In this study, I investigated whether the risk of predation can alter the reproductive effort in the blue mussel Mytilus edulis. In the field, I cultured blue mussels in the presence and in the absence of the starfish, Asterias rubens, using enclosures with two compartments. Two experiments were performed with field periods of 19 and 30 days, respectively. After the field exposure, the mussels were examined for weight of flesh and gonad tissue. In both experiments, the starfish-exposed mussels developed a significantly larger gonad to flesh ratio, compared with that of the unexposed control mussels. After 30 days, the exposed mussels had also lost flesh weight significantly, probably due to spawning. These changes suggest that M. edulis accelerates the gonad development and/or increases its reproductive effort in the presence of predators. Predator-inducible adjustment of life-history characters should be a beneficial trait for this sessile species, that typically encounters a high and variable predation pressure.