Date of Award

Spring 2007

Document Type

Legacy Thesis

Degree Name

Bachelor of Science (BS)

Department

Marine Science

College

College of Science

First Advisor

John J. Hutchens, Jr.

Abstract/Description

The role that cephalopods play in marine ecosystems carries great significance. Nearly all cephalopods are known to have short life cycles of rapid growth. They feed voraciously to meet a constant demand for energy. However, at a lower trophic level, some species, including squid, are a crucial prey item for other organisms, including humans. The impact on humans through fisheries is also an important factor affecting cephalopods. As most cephalopods live less than or equal to one year, the seasonal changes of biomass of a species can be dramatic. Numerous abiotic factors may affect cephalopod growth rates. However, little field data exists to examine such relationships. Current methods used to analyze growth of cephalopods include laboratory studies and statolith aging (restricted to squid). Statolith aging is a method of counting concentric growth rings on the statolith of squid and assumes that each ring represents one day in the squid's life. However, this only shows an approximate estimate of growth. The applications of tag and recapture methods to provide squid growth rates over known time intervals were pursued in waters off Bermuda. The effect of salinity on in situ growth of a squid, Sepioteuthis sepioidea, was investigated. Forty nine individuals were recaptured between September 14 and November 7, 2006. Salinity and temperature increased during this time, while average rainfall did not change consistently. At higher salinities, the growth of Sepioteuthis sepioidea appears significantly inhibited. Controlled laboratory analysis should be pursued to compare the effects of salinity upon cephalopod growth as compared with other influencing factors.

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