RECORD OF SARDINE EGGS, 1957 



A listing of aU hauls containing sardine eggs in the 1957 plankton samples 

 obtained on CCOFI cruises is contained In table n. The eggs at each station are 

 reported by age in days (A to D; see below) for two categories, normal and total. 

 Abnormal eggs have embryos that are stunted and misshapen, either due to 

 mechanical Injury during collection (rupture of the vitelline membrane) or to a 

 diseased condition of the eggs. Deteriorating eggs are eggs in such poor condi- 

 tion that they cannot be classified with certainty. 



The age categories into which sardine eggs are separated are the following: 



A - Eggs spawned within 24 hours of colleQiipn 



B - Eggs spawned within 24. 1 to 48 hours of collection 



C - Eggs spawned within 48. 1 to 72 hours of collection 



D - Eggs spawned within 72,1 to 96 hours of collection 



Unclassified (Unci.) - deteriorating eggs that cannot be aged with certainty, 



A dash (-) in table n indicates that the category was not represented at a 

 station, either actually or potentially. 



Considerable publicity has been given to the warming that occurred in the 

 CCOFI area during 1957 and which has continued to the time of writing this 

 report - May 1959 (Progress Report, 1 July 1956 to 1 January 1958, California 

 Cooperative Oceanic Fisheries Investigations, sponsored by the State of Cali- 

 fornia Marine Research Committee, pp. 7-26). The temperatures at which sar- 

 dine eggs were obtained during 1957 are given by month and area in text table 3. 

 A comparison with average "spawning" temperatures by area for the preceding 

 six years (1951-1956) foUows: 



1957 season 



Area 



Number of 

 observations 



Average 

 temperature 



Average 

 temperature 

 (1951-1956) Difference 



60-77 (complete season) 3 



80-93 (complete season) 16 



97-107 (complete season) 15 



110-120 (main spawning period) 11 



(late season spawning) 16 



123-137 (main spawning period) 8 



(late season spawning) 6 



140-157 (complete season) 



13.4 

 15.0 

 15.4 

 16.4 

 20,8 

 16.6 

 21.0 



14.7 

 15.1 

 15.4 



18,1 

 15.7 

 18.0 

 18.7 



+0.3 

 +0.3 

 +1.0 

 +2,7 

 +1.1 

 +3.0 



18 



