Temperature and Food-Ration Optimization in the Hatchery Culture of Juveniles of the Pacific Geoduck Panopea generosa

ABSTRACT This research examined the individual effects of temperature and ration on growth and survival of juveniles of the Pacific geoduck Panopea generosa Gould, 1850, in two separate experiments. Growth parameters measured included shell length, daily shell increment, individual total body wet weight, specific growth rate, individual total body dry weight, and total body ash-free dry weight (AFDW). Larvae in all treatments were fed a binary microalgal diet of Chaetoceros muelleri and Tisochrysis lutea mixed at a 1:1 ratio by AFDW. The temperature experiment examined the effect of four temperatures (7°C, 11°C, 15°C, and 19°C) using two geoduck cohorts. One cohort was comprised of larger juveniles (mean initial shell length ± SE, 3.22 ± 0.05 mm) and the other included smaller individuals (0.54 ± 0.01 mm) which were cultured for 28 days and 21 days, respectively. Using a separate cohort, the foodration experiment examined the effect of nine rations (0.0, 1.0, 2.0, 4.0, 8.0, 16.0, 32.0, 64.0, and 128.0 × 1...