Angular Substrate Preference and Molting Behavior of the Giant River Prawn, Macrobrachium rosenbergii, and its Implications for Cannibalism Management

Abstract

The Giant River Prawn is an important commercial species from southeastern Asia and has a large global market. It has a complex life cycle in which it undergoes several molting sequences. Many arthropods require firm perches on which they can perform ecdysis. We investigated preference for substrate slope and its influence on ecdysis. We discovered that prawns occupy horizontal surfaces more frequently than others, but during pre-molt and molt stages, they shift their habitat use to non-horizontally sloped surfaces. Here, they will flex their shell and later molt. We recommend modification of cannibalism management in commercial facilities by providing sufficient vertical (strongly preferred) or high-sloped (greater than 30 degrees) surfaces to facilitate ecdysis, while providing much horizontal space for foraging and other activities. This should create habitat separation between foraging and highly susceptible freshly-molted prawns, thus leading to reduced cannibalism-related mortality.\n\nFundingThis work was supported by the USDA Evans Allen Program at Langston University, Project Number USDA-NIFA-OKLUMCCALLUM2017.\n\nDisclosure statementWe acknowledge that there is no financial interest or benefit that has arisen from the direct applications of our research.