The King-Hida method of adjusting for day-night 

 variation in zooplankton volumes was tested. Statistical 

 problems due to a strong bias of hauls taken near noon 

 or midniglit. and. more important, the enormous geo- 

 graphical extent of the EASTROPAC cruises, which 

 covered a great diversity of ecological situations, pre- 

 clude the use of the method. Other methods of normal- 

 izing the data are being examined, but. until a satisfactory 

 method is found, only niglit-time hauls are being used, 

 except for determining concentrations of such organisms 

 as fish larvae which do not undertake diel migrations. 



All EASTROPAC micronekton collections, except 

 those from one cruise, have been sorted into major tax- 

 onomic categories and volumes measured. In addition, 

 about 25 percent of the samples have been sorted for 

 crustaceans down to family level. R.M. Laurs and M. 

 Blackburn (STOR) are collaborating in thesemicronekton 

 studies and have begun some statistical examination of 

 the data. 



A.R. Longhurst has continued his study of vertical 

 distribution of zooplankton in the EASTROPAC area by 

 means of profiles taken with his multiple serial plankton 

 sampler from 500 m. to the surface. These profiles were 

 taken during live cruises, and each contains between 50 

 and 75 subsamples; sorting into major ecological and 

 systematic groups has been completed for the first three 

 cruises. Data from the first cruise have been punched 

 onto computer cards and run througli a program which 

 generates histogram-type vertical profiles for each sorted 

 category. Tliese profiles show a remarkable concordance 

 between widely separated stations within similar ocean- 

 ographic regimes. They also show considerable differ- 

 ences between profiles that are typical of different 

 oceanographic regimes, or different ecological situations. 



G. Mattson 



Zooplankton ecology removing plankton samples from 

 filtering gauzes of new plankton recorder. 



SCRIPPS TUNA OCEANOGRAPHY RESEARCH 



M. Blackburn and his group continue their studies 

 of the relation between tropical tuna and their environ- 

 ment. They have been heavily involved in the field work 

 for EASTROPAC and have contributed in a major way 

 to the data collection. At the same time, they have been 

 completing their analysis of the work which has occupied 

 them for the previous 3 years on the "'local banks" fish- 

 ery for yellowfin and skipjack tunas off the western coast 

 of Baja California. This study is of great importance to 

 the fishery forecasting project described earlier, with re- 

 gard to both the general relation between tuna and their 

 environment, and to the planned extension of this pre- 

 dictive service to cover the fishery for tropical tunas. 



Behavior-Physiology Program 



Each of the four projects within this program is de- 

 voted to a particular aspect of the trophic and behavioral 

 relations of the important commercial fish in the Cali- 

 fornia region. 



The physiology project seeks to understand the en- 

 ergy budgets of our important commercial fishes and of 

 the organisms on which they feed. 



The schooling behavior project is planned to pro- 

 vide information on the internal structure of schools of 

 adult fish, including an understanding of the manner in 

 which fish react to one another and so maintain the struc- 

 ture of a school under varying conditions. 



The feeding behavior project recognizes that the 

 ingestion of food by an individual fish is the climax of a 

 complicated and plastic behavior pattern. This project is 

 planned to describe this behavior, particularly for an- 

 chovy and sardine. 



Finally, the rearing project seeks to develop tech- 

 inques for rearing larval pelagic fish from the egg througli 

 the larval stages and into the subadult stage under ex- 

 perimental conditions in the laboratory. 



PHYSIOLOGY 



R. Lasker's group has continued its studies of the 

 trophodynamics of the Califotnia Current food chain, 

 and Lasker maintained his interest in food chain research 

 during his sabbatical leave at the University of Aberdeen, 

 Scotland, where he investigated a sand-living copepod 

 (Asellopsis intermedial, important in the food chain of 

 Loch Ewe, and a dominant food organism for the flat- 

 fish living there. Since he found that the population of 

 copepods is discrete, spawns during a restricted period, 

 and has short-lived individuals, he was able to complete 

 an analysis of growth, mortality, and recruitment by 

 means of a length-frequency analysis and a carbon budg- 

 et from respiration studies. 



