Burge, Richard

Aquatic Commons

Vessel:  
Dates : 
Loca l i t y :  
Purpose: 
Procedure : 
Resu l t s  : 
S t a t e  of Cal i fornia  - The Resources Agency 
Department of Fish and Game 
Marine Resources Region 
Long Beach, Cal i f o rn i a  
CRUISE REPORT 73-KB-23 
ABALONE INVESTIGATIONS 
Prepared by Richard Burge 
KELP BASS 
September 17-22, 1973 
San Clemente and Santa  Cruz I s l a n d s  
1. To t a g  p ink  and green abalones and t o . i n s p e c t  new 
a r e a s  f o r  survey and tagging s i t e s .  
2. To o b t a i n  gene ra l  in format ion  on abalone cond i t i on ,  
behavior ,  competi t ion,  p reda t ion ,  and environmental 
cond i t i ons .  
3.  To i n s p e c t  r e l e a s e d  popula t ions  f o r  m o r t a l i t i e s  due 
t o  tagging .  
Scuba d i v e r s  picked aba lones  i n  pre-se lec ted  s tudy  a r e a s .  
Abalones were brought aboard t h e  KELP BASS, tagged and 
measured f o r  l e n g t h  and width .  Notes were taken  on each 
abalone concerning apparent  growth r a t e  and gene ra l  con- 
d i t i o n .  Most c u t  abalones were n o t  r e tu rned  a s  t h e i r  sur -  
v i v a l  r a t e  i s  low and t h e  l o s s  of hemocynin appears  t o  
a t t r a c t  p reda to r s .  
Tagged abalones were r e tu rned  t o  t h e i r  home r ee f  and u s u a l l y  
p l an ted  on a  f r e s h  abalone s c a r .  
Moderate s w e l l s  on September 17 a t  China P o i n t ,  San Clemente 
I s l a n d ,  prevented s a f e  d iv ing  ope ra t ions .  We then  moved t o  
North West Harbor, San Clemente I s l a n d ,  t o  t a g  green  abalone 
i n s i d e  Bird Rock; however, Naval underwater demol i t ion  
e x e r c i s e s  prevented d i v i n g  t h e r e .  
Opera t ions  were moved t o  Santa Cruz I s l a n d  on September 18 
t o  t a g  p ink  abalone.  An a d d i t i o n a l  320 p ink  aba lone  were 
tagged a t  our Gull  I s l a n d  s tudy  s i t e ,  i nc reas ing  t h e  tagged 
p ink  abalone popula t ion  t h e r e  t o  908. F i f ty - fou r  (14.4 
pe rcen t )  of t h e  abalone picked were badly  c u t  dur ing  p ick ing  
o p e r a t i o n s  and n o t  r e tu rned ,  wh i l e  43 (11.5 pe rcen t )  were 
c u t  o r  l i g h t l y  b l i s t e r e d .  
S ix t een  t a g  m o r t a l i t i e s  were recovered a t  Gul l  I s l a n d  from 
our  e a r l i e r  (August 10 and 11, 1973) tagging  pe r iod ,  i nc reas -  
i n g  t h e  p reda t ion  l o s s  t o  82 out  of t h e  o r i g i n a l  588 
(13.9 p e r c e n t ) .  The t o t a l  l o s s  t o  d a t e  from t h e  o r i g i n a l  
t agging  ope ra t ions  i n  August, including.  183 no t  r e tu rned  
due t o  bad c u t s  and t h e  8 2  l o s t  t o  p reda to r s  i s  34.4 pe rcen t .  
Th i s  f i g u r e  may be  cons iderably  lower than  t h e  p ick ing  l o s s  
i n f l i c t e d  by s p o r t  d i v e r s  and new commercial d i v e r s ,  a s  t h e  
Department d i v e r s  were a s s i s t i n g  dur ing  t h e s e  ope ra t ions  
were s k i l l e d  abalone p i c k e r s  and they  c a r e f u l l y  r e tu rned  
abalones t o  good s c a r s  and he ld  them u n t i l  they  r e a t t a c h e d .  
A t  Yellow B l u f f s ,  Santa  Cruz I s l a n d ,  we tagged 751 p ink  
abalone i n  25 t o  30 f o o t  depths .  An a d d i t i o n a l  270 
(26.4 pe rcen t )  were mor t a l ly  c u t  and no t  r e t u r n e d ,  wh i l e  
101 (9.9  pe rcen t )  of t h e  picked abalone were l i g h t l y  c u t  
o r  b l i s t e r e d .  Twenty-seven (3.6 percent )  of t h e  751 
r e tu rned  were known t o  be  l o s t  t o  p reda to r s  (sheephead and 
b a t  r a y s ) .  
Personnel  : Marco Mazarovich, Vesse l  Captain 
Richard Burge, Biologis t- in-charge 
S teve  Schu l t z ,  B io log i s t  
Robert Hardy, B i o l o g i s t  
J a c k  Ames, B i o l o g i s t  


Cruise Report 73-KB-23: Abalone Investigations

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Cruise Report 73-KB-23: Abalone Investigations

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