DELAYED GROWTH OF MUSSEL (MYTILUS-EDULIS) AND SCALLOP (PECTEN-MAXIMUS) VELIGERS AT LOW-TEMPERATURES

Veliger larvae of M. edulis (L.) from Menai Straits, North Wales [UK], were maintained for up to 2 mo. during 1981 at 5.degree. C and then grown on to metamorphosis at 17.degree. C. Larvae so treated showed similar low mortality and equivalent spat production to control larvae. Growth rate at 17.degree. C was less in treated larvae than in controls, but treated larvae grew a little during the period at low temperature. Larvae of P. maximus (L.) from the Irish Sea suffered high mortality at low temperature but larvae surviving 2 wk at 8.degree. C could be grown on to spat at 17.degree. C. The longevity of M. edulis larvae is discussed in relation to the genetic homogeneity of adult populations around the UK.