Gotshall, Dan

Isaacson, Peter A.

English

Aquatic Commons

e. 
The Re.qurces Agency of California 
.. ;,,'. :Department of Fish. and Game 
Marine Resourc.s Operations
California State Fl,herles Laboratory 
. TeI'Ul1nal Islan4, California 
.Cruise RepOrt 64-S-5 Shrimp 
Prepared by Jan Gotshall and Peter A. Isaacsol<l / "" 
~:, .. 
V•.ssel: 
Dates: 
Localities: 
Purpose: 
Results: 
N. B. Scofield 
peparted September 2, 1964 from San Pedro 
Returned September 16, 1964 to San Pedro 
Cpa,tal waters from .,Zuma Beach, Califomia, to. 
Cape Ferrelo, Oregon 
1. To make \,lnderwate1:' observations of the gulf
shrimp trawl in operation and make needed 
adjusDments in doors and net to insure 
maximum fishing efficiency. 
2.  To locate concentrations of pink shrimp,
Pandalus Jordani, for determining population
estfmites and natural mortality rates. . 
3.  To determine size, sex, and weightot shrimp.• 
4.  To save all cephalopods, rare fish, and in-
vertebrate, fo; the State Fisheries Laboratory,
Terminal Island. . 
5.  To identify and record incidentally-caught fish 
and invertebrates. 
6.  To collect stomachs fro1P hake, Merluecius . 
productus, and other species oflncla~tilly­

cauiht !lsh for juvenile shrimp abundance index 
study. " 
One day was spent off ZWI1&. Beach, where tw~ tows were 
made in 8 fathoms. DeparDment SCUBA divers," made 
dives on both tows to observe the n~t in operation.
The doors were function1i1g satisfactorily,but it was 
felt that the foot rope,tI'as fishing, too' far· from the 
bottom. Chain was added which brought it to within 
.4-,6 inches of the bottom. The chain was later removed 
after talks with cODllierci~l'fishermen WQo .... reported
that they fLsh their nets about 12 inclu!s off·. the 
bottom; at the time these chains were removed a tickler 
chain was added to the gear to run about 5 feet in 
front of the center of the lbot rope. Moving pictures 
were taken of the net and the fishes' reactions to 
the net. The width of the net when fishlngwas
esttmated to be 25 feet and the height 6 feet. 
- 2 -
cruise Report 64-8-5 Shr1,alp' 
Fifty-six tows were made in the combined survey 
areas as follows: Zuma Beach, 2 tows; Fort Bragg 
(B-1), 5 tows; Redding Rock-Klamath ~ver.c 42~··tows; 
Oregon border, 7 tows. 'Ibe g~4ru8C!d''',,_ 4J.-foot 
head rope gulf otter trawl With 1-1/2 inch stretch 
mesh in the cod enQ,. Of the tows made 1D_, ..the~ shrimp 
beds, 48 were of 20 minute duration and 6 1asted30 
minutes. On 15 of the tows, a 1/2-1nc~:>. s.tre.tch mesh 
liner -was used to. capture juvenile shr1mp: ,and 
detendae escapement of adults. The tows were made 
in depths ranging from 8 to 165 fathoma. 
An average of 229 pounds of juvenile. $~1JDp per hour 
was caught 1n the liner. These juveniles averaged 
734 to .the pound. The .average escapement of ,adu1ts 
into the liner amouated to 10.8 percent: and ranged 
from 1.0 petcentto 44.4 percent. Adults in the ./; 
liner averagecl ....l10 pe; pound. Seventy.percent of the 
adults 1n the liner were l-year-olds; 29.2 percent 
were 2-year-olds; and 0.8 perceDt, 3-year-olds. 
Area A. The seven tows made on the bed lying aD 
the Oregon-California bord'er yield'ed aD average 
catch per hour of 112 pounds. The total area was 
estimated to enc~a88 16 square miles ~and cOiltain 
159,393 pounds of shr~. 
The bed 1y1ng off n_tl\.River and RecidlDgllock was 
estimated to cODtain 1 1671,856. pounds of shrimp in 
an area of 67 squareJD11es. The average catch per
hour was 267 pounds; raaging from 50 to 855 .pouads. 
The average count per pound for both beds was 84 and 
ranged from 64 to 111. one-year"olds foxaed-;i52 •.6 
percent by number. of :the population: of···· both j)$dSj 2-
year-olds 42.5 perceDt, and 4.9 percent;.·were·~;3-years 
old. .. 
Head roe was oblJerved in 90. 7 perct;!ot of the. females 
and 40.3 percent of the traDs1tlona18.,_~ "J;pcLdeatal 
fish ~atche8 at t~, were quite he~. S'leader sole, 
LIf!setta ai1!s ,appeared in all oftbeq,wa; Dover 
soe~ IIlcrostOll&1s pac;1f1cus, appeared t~9G j»ercent 
of the tows· ~ sr_eDsEiflpe rockfish.. Se!)utocies
e10n atus, ionpose 'skate, J.l.ja rhina, eel pouts, 
r on cortezlanas, ~d LrCOGOpsllalaCifica, slim 
scu p n, Ldiitliiis 1,"lOrellus, and e ~ared in 
over 60 percent of .t&j boWs. In all, 46 species of 
fish were identified in the tows. 
,...,:. 
- 3 -
Cruise Report 64-S-5, Shrimp 
Twenty-eight dogfish, Sgualus acanthi.., weEe tagged
in cooperatio~'With the AiDirtcan·lnst:lbite ox 
Biological Sciences shark tagging proar-.'; 
Area B-1: Five tows were made on the~M:~ 1 bed. 
'file average catch per hour was 139 p0UD4.~wtth the 
best tow of 428 pounds per hour 10cate4 ,8.5~1C!s 
SSW of cape Vizcaino. The count per.poundT~ed 
between 77 and 87 with an average of 80.4. Ooe-
year-olds formed 44.8 percent by number of ~e 
samplestaken 2-year-olda 52.0 percent, and 3.2 
percent were j -year-olds. 
Several rare and unusual fishes were saved for 
special study. A collection was also'#~ J)f
representative invertebrates found in,association 
wi th shrimp. 
"r..-el: R. B. Mitchell Vessel Captain
i '" D. Gotshall, BIolOgist-in-charge! September 6-12 
P. Isaacson, September 2-12, Bio ogist~in-charge 
September 2-5. . 
K. Ujita, seasonal aid, September 6-9 
J.Robinson, Oregon Fish Cqmmission, September 5-12 
, Terry Egan Humboldt Stand4rd, September 9 
Douglas Di!l, Humboldt Standard, September 9 
N. B. SCOFIELD 
64-5-5 OREGONAREA ~An 
CALIFORNIA 
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st. George 
~40' 
124°20' 
Klamath 
River. 
5 mi les PACIFIC OCEA~ 
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fl. B. SCOFIELD 
6~S-5 . 
AREA 8-1 
'X = Com'm'erc ia I ~ .at tiMe of 
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\ CALIFORNI A 
Tows in Area 
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Cruise Report 64-S-5 Shrimp

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Cruise Report 64-S-5 Shrimp

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