Density, distribution and life history characteristics of the mantis shrimp, Squilla empusa, in the muddy sediments of Narragansett Bay, RI

Imam Syuhada, University of Rhode Island

Abstract

The mantis shrimp, Squilla empusa are benthic, megafaunal burrowers and a predatory species. Its abundance is significantly correlated to sediment type. Mantis shrimp reside in self-excavated burrows and established different burrow shapes in the winter and summer seasons. In Rhode Island, mantis shrimp have traditionally not been considered to have commercial value in the fishery. However recently, a new market for this species has emerged from local Asian restaurants in Boston and New York, and several fishermen in Rhode Island are periodically targeting the species in a directed fishery. The mantis shrimp fishery in Rhode Island occurs mainly in Mount Hope Bay. ^ Our study of mantis shrimp density and distribution was conducted in both the winter and summer seasons. In the winter season the study was conducted based on video observations of burrows as an indicators of individual mantis shrimp, while in the summer season, the study was based on repeated trawl surveys, and individual mantis shrimp captured by the trawl were enumerated. In the winter season, we found that the density mantis shrimp burrows or individuals was 1.7 and 1.1 animals/m2 using sequential and continuous data analysis methods, respectively. Across locations, using both the sequential and continuous data analysis methods, we found that mantis shrimp density was significantly different, where Mt. Hope Bay which was dominated with sandy mud sediments had the highest mantis density and Providence River which was dominated with muddy sand sediments had the lowest density. In the summer season, trawl survey yielded very low estimates of mantis density with an average across the locations of 0.02/m2. ^ We found that mantis shrimp experience isometric growth with ln (W(gr)) = −11.129 + 3.00 ln (L(mm)). Females are slightly larger than males in mean length, however the difference is not substantive so as to be considered in growth models. We found that there was seasonal growth in mantis shrimp and the annualized instantaneous growth coefficient (K) is 0.4, and maximum length is 202 mm. Mantis shrimp have 50 % probability of maturity at 120 mm in their second year of life (age 1). We believe mantis shrimp spawn in late winter and early spring. Recruitment to the fishing gear starts in the late fall and early winter in the first year of life, but these small animals are discarded. The mantis shrimp life span is estimated to be 3 years, and only animals in their second and third years of their life are retained in the fishery.^

Subject Area

Biology, Ecology|Biology, Oceanography|Agriculture, Fisheries and Aquaculture

Recommended Citation

Imam Syuhada, "Density, distribution and life history characteristics of the mantis shrimp, Squilla empusa, in the muddy sediments of Narragansett Bay, RI" (2011). Dissertations and Master's Theses (Campus Access). Paper AAI1497494.
http://digitalcommons.uri.edu/dissertations/AAI1497494

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