Collier, P. C.

English

Aquatic Commons

,
 
Vessel: 
Dates: 
Locality: 
Purpose: 
Operations: 
Results: 
State of California - The. ResQurces Agency

Department of Fish and Game
 
Marine Resources Region

long Beach, .California
 
CRUISE REPORT 71-5-7 CRAB 
Prepared by P. C.Collier 
N. B. SCOFIELD 
Depart San Pedro, September 22, 1971
 
Return San Pedro, October 7, 1971'
 
Coastal waters in the San Francisco area from Pt. San Pedro 
. to Bod~·ga·Head. 
1.	 To assess the relative abundance of incoming year
 
classes of the market crab, Cancera ~agi8tera.
 
2.	 To determine the depth distribution of male and female
 
market crabs.
 
3.	 To collect juvenile'petrale sole for the Bottomfish
 
Program.
 
Trawling for .crabs was conducted in inshore areas at depths' 
between 6 and 12 fathoms in Bodega Bay, Fourfathom'Bank, 
and the South Channel area between the Golden Gate and 
Pt. San Pedro (Figures 1 and 2). Trawling was also done 
on two transects at five (5) fathom intervals between 10 
and 50. fathoms in the Gulf of the Farallones. Trans·ect 
number 1 extended from the 10 fathom line near the San 
Francisco Light Buoy to 50 fathoms southeast of the Faral10n 
Islands (Figurel). Transect numb~r 2 ext~nded'from 15 
fathoms 10.8 miles ENE of Pt. Reyes to 55 fathoms· WSW of 
Pt. Reyes (Figure 2)~ 
Eight 40-inch traps were set at each of 18 stations along 
the two transects described above. Six40-inch.trapswere 
set at each of four stations in outer Bodega Bay. After 
setting the traps and trawling, the traps were retrieved 
approximately 24 hours la·ter. Squid and rockfish carcasses 
were· used in conjunction as bait in the traps. 
A total of 1,399 crabs consisting of 1,045 male and 479 fe­
males were caught at 22 trapping stations. Twenty-seven 
percent (278) of the males were of legal size (159 nnn) and 
of these, 79.5 percent were hard, 19.1 percent'were filling 
and 1.4.percent were soft. No juveniles were caught in 
the traps. Juveniles were those crabs 50 mm or less in 
size (1971 year class). 
A sub-legal male tagged at Pt. Molate near Richmond on
 
June 22, 1971 was recaptured 1 mile WNW of Double Pt. on
 
September 30, 1971; a movement of approximately 27 miles.
 
Personnel: 
MRR-Lal.l45 
11-19-71/cg 
- 2 - • 
Trawling produced a total catch of 7,815 crabs, of which, 
98 were female, 262 were males, and 7,455 were juveniles. 
Three percent (8) of the males were of legal size and of 
t.hese 12 percent (1) were soft. A .to·tal of. 99.9 percent 
of the juveniles were caught in Bodega Bay. A sample of 
16 juvenile petrale sale was saved for Bottomfish Investi­
gation. 
A comparison of numbers and sizes of crabs trapped at 
various depths on the two transects reveals that in gen~ral 
at shallower depths the greater the number of crabs were 
caught (Tables 1 and 2). .on transect numb"er 1, 88 percent 
of the trapped crabs were caught in 25 fathoms of wa·ter or 
less. Transect ntlmber 2 showed a similar pattern· with 84 
percent of the crabs being trapped at depths of 30 fathoms 
or less. 
Tony Black, Vessel Captain 
P. C. Collier, Biologist-in-charge 
W. A. Dahlstrom, Biologist, September 27 
Gary Lawton, Project Transition Aid 
TABLE 1 
Crab Depth 'Distribution by Area 
CRUISE 71-8-7 CRAB 
Transect Number 1 -Farallones 
Trap Catches 
Depth 
in 
Fathoms Total No. 
Average Size 
(Carapace Width) 
mm 
Size Range 
(Carapace Width) 
mIn 
L 
cf 
8L 
rJ ~ 
T 
r!~ 
L 
c! 
8L 
rJ ~ 
T 
cf9 
L 
c! 
SL 
cf ~: , 
10 44 169 59 272 166.8 . 140.3 132.1 142.8 
160 
to 
185 
116 
to 
158 
108 
to 
166 
15 30 183 47 260 168.5 140.4 130.4 141.8 
160 
to 
199 
100 
to 
158 
114 
to 
171 
20 35 107 43 185 169.5 142.8 131.2 145.2 
159 
to 
195 
121 
to 
158 
108 
to 
177 
25 21 21 28 70 173.9 140.9 142.4 151.4 
165 
to 
205 
129 
to 
158 
107 
to 
172 
30 6 1 8 15 176.2 152 166 169.1 
169 
to 
189 
-
152 
-
146 
to 
178 
35 2 1 6 9 179·5 152 161 164.1 
173 
to 
186 
-
152 
-
149 
to 
168 
40 
45 
3 
. 
4 
0 
3 
13 
47 
16 
54 
179.6 
179 
-
152 
155.8 
154 
160.3 
155.4 
172 
to 
189 
165 
to 
190 
-
148 
to 
158 
126 
to 
171 
122 
to 
171 
50 1 1 8 10 180 149 157 159 
-
180 
-
149 
132 
to 
171 
*55 - - - - - - - - - - -
*55= No samples taken 
L = Legal 
8L. = Sub-legal 
T = Total 
, 
TABLE 2 
Crab Depth Distribution by· Area 
CRUISE 71-8-7 CRAB 
Transect Number 2 - pt. Reyes 
Trap Catches 
Depth 
in 
Fathoms Total No. 
Average Size 
(Carapace Width) 
rom 
Size Range 
(Carapace Width) 
mm 
L 
cf 
8L 
c! ~ 
T 
.c!~ 
L 
cf 
8L 
cf ~ 
T 
cf\./ 
L 
cf 
8L 
c:! ~ 
* 10 - - - - - - - - - - -
15 6 13 52 71 163."8 143.7 155.6 154.1 
159 
to 
168 
122 
to 
158 
110 
to 
175 
20 
25 
11 
17 
8 
2 
48 
18 
67 
37 
168.7 
171.1 
146.8 
155 
157.8 
157.4 
153.3 
163.5 
161 
to 
180 
159 
to 
190 . 
131 
to 
154 
154 
to 
156 
107 
to 
176 
144 
to 
187 
30 16 2 22 40 178.2 143.5 163.2 168.2 
159 
to 
193 
134 
to 
153 
131 
to 
178 
35 3 1 13 17 168.3 158 160.4 161.7 
167 
to 
171 
-
158 
-
152 
to 
179 
40 5 0 7~ 12 187 - 162.,4 172.6 
169 
to 
198 
-
-
-
143 
to 
177 
45 2 
-
2 4 186.5 . 
- 157· 171.7 
180 
to 
193 
-
-
-
151 
to 
163 
50 2 - - 2 182.5 - - 182.5 
182 
to 
183 
-
-
-
_. 
-
-
55 - - 7 7 - - 165 165 
-
-
-
-
-
-
155 
to 
185 
*10 = No samples taken. 
L = Legal 
'S1 ::: Sub-legal 
T = Total 

r-i 
l' 
.... 
,2milesl Crab Cruise "'J 
71-8-737°50' I 
/1 ./o 
o 
o ./ Fourfathom 
'~ 
N 
" B~nk/ 
/ \\ 
San Francisco,. 
~.I
'i>/.
Light Buoy..···· \ 
.® "'. "'. \. '~  ".,.10 fms. 
'-'e'
'--.., '~,,' ",. ..... _.\~e.'  S. E· Farallon Islands ... 
\ 
\." 
" \ 
e.
...• ~,II, , '~  \ 
'''-:" _e e, •••• I",~ 
\ 
\; 
l 
I 
Point / 
San Pedro~  
Crab traps \ 
Crab, trawl \ 
\ . 
I 
, 
~'igure  1 

----
---
---
Crab Cruise 12 Miles I71-8-7 
Bodega Bay 
C'rab trawl 
.. . . . ... C'rab traps 
-~ 
o 
(Y) 
C\J 0 
r-t 38 10 
' 
50 fms 
Drakes BayPoi.nt 
Reyes 
...... -.. 
......... 
--- ....~ 
Figure 2 



Cruise Report 71-S-7: Crab

http://aquaticcommons.org/2045/1/CR_71-S-7.pdf

Cruise Report 71-S-7: Crab

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