Hopkins Marine Station Student Paper

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Title: Investigation of Octopus rubescens population dynamics: population fluctuations at 200 m depth in Monterey Bay
Student Author(s): Hulvey, Kristin B.
Faculty Advisor(s): Baxter, Charles
%E Watanabe, James
Pages: 33
Location: Final Papers Biology 175H
Date: June 1997
Abstract: In October of 1991, a National Marine Fishery Survey conducted at the 200 m depth contour along a segment of sand-mud canyon bottom between Ascension Canyon and Monterey Canyon in the MOnterey Bay revealed an unuseally large population of Octopus rubescens (852 octopuses ha-1, SE=179.8). When re-sampled in March of 1997 using a remotely operated vehicle (ROV),the O. rubescens population was found to have significantly decreases in size (3 octopuses ha-1, SE=3.2, p<0.001). Fishery effects on predatory rockfish and factors affecting juvenile recruitment wre found to be the most plausible causes for the large 1991 O.rubescens populations. The effect of these factors could not be established for the smaller 1997 populations because of insufficient data. Large increases in numbers of harbor seals, Phoca vitulina, within the bay may be contributin significantly to the O. rubescens decline.