Appendix E. Grass shrimp collection, recovery, and processing.
Grass shrimp were collected from salt-marsh habitat adjacent to the University of Southern Mississippi Gulf Coast Research Laboratory (USM GCRL), Ocean Springs, Mississippi, USA, twenty-four hours prior to deployment. Lengths of experimental shrimp (rostrum to telson) were measured to the nearest 0.01 mm using a Mitutoyo model 85 dial calipers. Grass shrimp ranging from 25 to 35 mm length with no visible external parasites were randomly assigned to replicates. Experimental grass shrimp for individual replicates were held separately in labeled Ziploc containers with 1.0 mm Nitex-covered windows. Containers were held in an aerated 80-quart cooler filled with collection site water. Cooler water was exchanged with Middle Bay water over a 2-h period prior to deployment to allow shrimp to adjust to any temperature and salinity differences.
After the experiments were concluded, recovered grass shrimp were identified to species (only P. pugio recovered), and their lengths compared to pretreatment lengths in order to discern experimental animals from new colonists. Recovered and “new” shrimp recruits and were easily distinguished by their sizes. Ranging from 18 mm to 22 mm in length, new shrimp did not reduce the epiphyte load within microcosms (Morgan 1980). All shrimp treatments were equally accessible to new shrimp.
Morgan, M. D. 1980. Grazing and predation of the grass shrimp Palaemonetes pugio. Limnology and Oceanography 25:896–902.