On Physiological Aspects of Black spot Appearance in Shrimp

Abstract

The incidence of black spots in shrimp was once again investigated, with emphasis on physiological aspects such as molting cycle stages, sex and influence of traumatism on live shrimp during storage in ice. Appearance of stronger discoloration in females, with a statistical significance, followed a tendency similar to the one observed in lobsters. Inflicted injury did not always induce discoloration in shrimp stored in ice, but when shrimps have been submitted to heavy traumatism and/or blow, discoloration was found to show as far as the superficial muscle. On the other hand most of the common natural appearance of black spots remained in the shell after peeling, and those left off on the superficial muscle could be scrapped off the black membranes. Anesthetizing of live shrimps in iced water before beheading, that is, application of Euthanasia treatment, showed to have an effective bearing in inhibiting formation of melanin, such as done in the case of lobsters. © 1984, The Japanese Society of Fisheries Science. All rights reserved.