Studies on the Maintenance of Adult Squid (Loligo Pealei). I. Factorial Survey

This paper reports a factorial survey of conditions affecting the survival of the squid, Loligo pealei, in laboratory aquaria. Running seawater and continuous illumination were provided to various numbers of animals kept in 520 liter experimental "cells." A total of 468 squid were studied in 16 separate experiments run between May 11 and November 23, 1970.2. Three imposed factors were studied simultaneously in any one experiment. These included feeding, crowding, relative water temperature and "cell" shape. The effects of uncontrolled factors such as ambient seawater temperature, age composition, size and sexual maturity were also evaluated.3. Mean survival of all squid was 87 hours and maximum survival was 666 hours. Analyses of variance demonstrated better than 99% confidence of significance in the factor, "cell" shape (rectangular "cells" produced longer survival than square ones). Mixtures of dissimilar age groups appeared to be detrimental in the survival of the younger group, and breeding animals (one-and two-year olds) did not live as bug as some sexually immature individuals.4. Collisions with the aquarium walls are discussed as likely causes of mortalities. Behavioral observations are used in evaluating the probabilities of these collisions.