Gregory, P. A.

English

Aquatic Commons

Vessel: 
Dates: 
Locality: 
Objectives: 
Operations: 
Results: 
State of California The Resources A~encyp 
Denartment ~f f1~h and Ga~e
 
t1ari ne Resources Region 
California State Fisheries Laboratory
Terminal Island, California 
CRUISE REPORT 69-5-6 
BOTTor1FISH PROGRAr1 
Prepared by P. A. Gregory 
N. B. SCOFIELD 
Departed San Pedro August 25, 1969. 
Returned San Pedro September 30, 1969. 
Northern California from Cape Mendocino to Crescent City. 
To obtain population parameter estimates of Dover sale, Miaro-
stomus pacificus, in the Eureka area by: 
a. Tagging, following a systematic random sampling scheme, 
to obtain fishing mortality estimates. 
b. Collecting age composition data from pre-fishery recruits 
to obtain estimates of natural mortality. 
c. Collecting age-length and age-weight data for von Berta-
lanffy growth estimates. 
Trawling stations were selected along six transects (Figure 1) 
at 20-minute latitude lines between Cape Mendocino and Cape 
Sebastian. The first station on each transect was randomly 
selected between 5 and 25 fathoms with the remaining stations 
spaced at 3 mile intervals to 1,000 fathoms. In all, 68 sta-
tions were established. 
Dover sole, fully vulnerable (356 mm tl and greater) to the 
commercial fishery, were tagged \tlith spaghetti tags. Every 
fifth fish of the first 1,200 fish was double tagged with a 
Petersen disc tag; thereafter every tenth fish was double tagged. 
All Dover sole less than 356 rom tl along with a representative 
sample of fish over 356 mm tl were retained for age-length and 
age-weight studies. 
Thirty-two 10- to 30-minute tows were completed along the first 
four transects (Figure 1); a few stations were deleted due to 
unsuitable bottom. A total of 2,185 Dover sole was tagged from 
depths of 28 to 465 fathoms; the majority was taken between 300~ 
390 fathoms. Jellied Dover sole were encountered in depths over 
300 fathoms, and the incidence of jellied fish increased in 
deeper stations. 
Samples were obtained for studies of age-weight and age-length. 
All fish less than 356mm tl were retained to obtain estimates 
of natural mortality. 
Personnel: R. B. ~titchel1, Vessel Captain L. Quiroll0, Biologist 
P. A. Gregory, Biologist-tn-charge H. Ness~Seasonal Aid 
MRR~TI/135 - lO-20-69/cg J. Crane, Visiting Scientist, U. C., Davis, 8-31 - 10-1 
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Cape Sebastian 
Oregon
--_ .. -- .... .-_-
California 
Trawling Transect-----
Trawl ing Sta tion '" 
Figure 1 


Cruise Report 69-S-6: Bottomfish Program

http://aquaticcommons.org/1953/1/CR_69-S-6.pdf

Cruise Report 69-S-6: Bottomfish Program

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