GIRI, T.; Texas A&M University: The occurrence of epibiota on the peppermint shrimp, Lysmata wurdemanni, and the effect of salinity changes on grooming behaviour

Exposed substrata in marine environments are quickly colonized (fouled) by sessile organisms, such as protozoans, bryozoans and barnacles. Since hard substrate may be a limiting resource, epibiota will often attach to the external surfaces of benthic organisms. Peppermint shrimp (Lysmata wurdemanni) with considerable epibiota attached were collected along a rocky groin in Galveston, Texas during Spring 2001. The fouling organisms were identified as epistylidid ciliates, bryozoans (Membranipora sp.) and estuarine barnacles (Balanus improvisus). Barnacles were predominantly found on the carapace and abdomen of shrimp, with the largest barnacles estimated to be between 20 and 26 days old. It was hypothesized that a large increase in precipitation, and a subsequent decrease in salinity along the Gulf of Mexico coast, created conditions optimal for the settlement of barnacle cyprids while also suppressing grooming behaviour in L. wurdemanni. In a controlled study, a decrease in salinity resulted in a general reduction in total grooming activities. An examination of specific grooming behaviours found that L. wurdemanni significantly decreased grooming of the carapace, pereiopods and anteroventral region, but did not significantly decrease grooming of other body areas. Changes in salinity appear to alter the pattern of grooming activity, and may allow subsequent colonization by epibiotic organisms.