Cruise Report 72-KB-13: Jack Mackerel tagging program

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Cruise Report 71-KB-19: Jack mackerel tagging program

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Results of Jack Mackerel tagging study, 1971-75

Methods and materials used to tag and recapture jack mackerel, Trachurus symmetricus, off the coast of southern Ca1ifornia and Baja California, Mexico, are described. Tagging, recapture, and movement data resulting from this program are reported. Analysis of these data indicates substantial movement of jack mackerel within the range of the California fishery and suggests a seasonal inshore-offshore movement pattern. (13pp.

Results of the jack mackerel subpopulation discrimination feasibility study

A report is made on the feasibility of discriminating subpopulations of jack mackerel, Trachurus symmetricus, off of the southern California and Baja California coast. Histochemical, morphometric, and meristic characters are compared from four samples of approximately 200 fish each taken from three areas. The data are analyzed for homogeneity by chi-square tests. Heterogeneity was found only in anal fin ray counts. Recommendations for a comprehensive study are made. (16pp.

A status report on the Jack Mackerel tagging program

Methods and materials used to tag and recapture jack mackerel, Trachurus symmetricus, off the coast of southern California and Baja California, Mexico, are described. Tagging, recapture, and movement data resulting from this program are reported. Analysis of this preliminary data indicates a seasonal inshore-offshore movement pattern for this species within the range of the California fishery. (9pp.

Dungeness crab research program

In 1974, the California State Legislature, recognizing the problem of low yields from the Dungeness crab resource of central California, directed the Department of Fish and Game to conduct an investigation into the causes of the decline. The Operations Research Branch of the Department has conducted preliminary studies and field operations necessary to formulate the Dungeness Crab Research Program. The objectives, research design, and work plans are presented for a 4-year program from July 1, 1975 through August 31, 1979. (38pp.

Dungeness crab research program: Report for the Year 1976

All larval stages of the 1976 year class, with the exception of the 5th zoeal stage, were found in Gu1f waters January through March. The first post-larval stage was collected in San Pablo Bay in May. Fifty percent of 1976 year class crabs entered the Bay complex as compared to nearly 80% in 1975. The 1976 year class appears relatively weak. No electrophoretic polymorphism was found in Cancer magister to be of value in Dungeness crab population determinations. Multi-variate correlations comparing crab landings with an array of oceanographic parameters and the crab density dependent factor were computer-run for both northern and central California. The most significant correlating factors at the time late stage larvae prevail were sea level and atmospheric pressure for central California and, for northern California, the density dependent factor and sea surface temperature. Female crabs held at controlled temperatures indicated gonad maturation and spawning may be induced by increased temperature. Analyses of crab tissues revealed burdens of petroleum hydrocarbons, silver, selenium, cadmium, and PCB's higher in central California crabs, while DDE was found in higher amounts in northern California crab tissue. Thru-flow culture systems were developed which should yield about 163 megalopae of Dungeness crabs in 63 days from 1,200 laboratory hatched zoeae.(46pp.

A checklist of zooplankters from the Gulf of the Farallones and off Northern California

Plankton samples were collected from January through June 1975-80 as part of the Dungeness Crab Research Program. Zooplankters were identified and enumerated from 1975-77 and 1979 samples taken in the Gulf of the Farallones and from 1979 samples off northern California. A checklist of zooplankters found in these samples is presented along with information on location, frequency of occurrence, and density. (57pp.

Fish Bulletin 172. Life History, Environment, and Mariculture Studies of the Dungeness Crab, Cancer Magister, With Emphasis on The Central California Fishery Resource

This report describes the results of the California Department of Fish and Game's Dungeness Crab Research Program (1974–1980) plus several related studies and provides a detailed history of the California fishery. The Dungeness Crab Research Program was developed in response to a severe and sustained decline in central California Dungeness crab landings; this decline is the primary focus of the investigations presented in this report. Research results are presented for life history, environmental, and mariculture studies relating to egg, larval, juvenile, and adult stages of the Dungeness crab. Specific areas of study include stock identification; larval and juvenile dynamics focusing on movement, distribution, relative abundance, age and growth, and predation; impacts of commercial trawl fishing; ocean climate and its effects on life cycle stages and fishery landings; reproduction; pollution such as chlorinated wastewater, toxic trace elements, pesticides and PCB's, and hydrocarbons; and laboratory culture techniques. This report concludes with a summary of the Dungeness crab life cycle and research results and a discussion of management options and further research needs