AGARUM KELP BEDS AS NURSERY HABITAT OF SPOT PRAWNS, PANDALUS PLATYCEROS BRANDT, 1851 (DECAPODA, CARIDEA)

The spot prawn, Pandalus platyceros Brandt, 1851, predominantly uses kelp beds of Agarum sp. as nursery habitat in waters of southern British Columbia. Census data indicate interannual fluctuations in numbers of shrimp settling into nurseries. Analysis of size samples indicates settlement primarily in May and June, with lesser rates of settlement through the summer. Growth of about 3 mm CL per month can occur through summer and fall, with juveniles apparently emigrating from nurseries, starting in the fall, at sizes of 16-20 mm CL. Juveniles which fail to reach such size before winter remain in the nursery habitat, with slower overall growth at about 1 mm CL per month. This difference in duration of residence in kelp bed nursery habitat, together with different juvenile growth rates, leads to the conclusion that the age of spot prawns at a given size will be variable. Due to this variable early life history and growth, length frequency modes of spot prawns could include a mixed age group.