Hopkins Marine Station Student Paper

Browse Titles | Search Citations & Abstracts

(full paper is archived in the Miller Library)

Title: Assessment of net damage to market squid eggs: a lab and field study
Student Author(s): Mathes, Chris
Faculty Advisor(s): Baxter, Chuck
%E Gilly, William
Pages: 30
Location: Final Papers Biology 175H
Date: June 1987
Keywords: biology of cephalopods
Abstract: Squid boats in the Monterey squid fishery utilize Italian lampara nets that have chains as lead-lines. Two experimental half-purse seine nets are the other type of gear used (spring, summer 1987). Squid egg cases were collected and then damaged with the assumption that gear net lead-lines drag across/through egg masses and potentially cause an increase in squid egg mortality. Egg cases traumatized mid-way through development experienced a higher estimated percentage of mortality (EPM) than those damaged at early or late stages, for low levels of damage (0 and .21 kg). Misdeveloped embryos occured most freqently in these mid-stage egg cases. Higher levels of damage (1.2, 2.1, and 3.0 kg) resulted in significant increases of EPM for all three stages. Field work included an observation aboard one of the squid boats that had a half-purse-seine net. Pelagic organisms were 100% of this catch, suggesting that this net did not drag the bottom significantly during this particular set. Variation of developmental stages within three egg clusters suggests that larger egg masses may have variation within. Attempts to restrict fishing above egg masses in mid-stages would be futile because of the mixture of stages within these egg clusters or egg masses.