Viability of frozen algae used as food for larval penaeids

Abstract

Freezing with added chemicals as flocculants and protectants as means of preserving stock cultures was tried with four species commonly used as larval food. The species were Chaetoceros calcitrans, Skeletonema costatum, Tetraselmis chuii , and Isochrysis galbana.

Except in I. galbana , this method successfully preserved the viability of the algae tested. C. calcitrans , was viable up to eighteen months storage; T. chuii , four months; and S. costatum , two months.

Cryophylaxis did not seem to greatly increase the viability of frozen cells except with T. chuii ; however, with the diatoms, viability was preserved regardless of the harvesting flocculant used and whether or nor protectants were added.