FISHERY BULLETIN: VOL. 74, NO. 2 



may be able to gain insight into stock- 

 recruitment relations and be able to predict the 

 effects of long-term environmental changes. 

 Some specific recommendations for further work 

 are listed below. 



1. A minimum of three surveys should be con- 

 ducted between late January and early June 

 to monitor initial hatching, production, rate 

 of development, and dispersal of the larvae. It 

 is imperative that survey coverage be ex- 

 tended along the Oregon coast to observe 

 patchiness and alongshore dispersal. A grid 

 of stations to within 30 miles of the coast 

 from at least Cape Blanco, Oreg. to Cape 

 Flattery, Wash, is recommended. A sufficient 

 time series of data is required to adequately 

 assess yearly changes in the larval popula- 

 tions in order to gain insight into mortality 

 processes. Also, a long-term series is needed 

 as a background of knowledge upon which 

 more specialized short-term studies can be 

 based. Six or seven years of plankton sam- 

 pling seems to be a minimum time series for 

 establishing trends, although 10-15 yr are 

 required to substantiate significant differ- 

 ences. 



2. Intensive close-order grid sampling on a 

 short-term basis, following a fairly well- 

 defined and homogeneous "patch" of larvae, 

 should be conducted to assess in more detail 

 mortality and feeding in good and poor areas. 



3. This study emphasizes the need for more de- 

 tailed oceanographic studies in the nearshore 

 environment and how they affect the popula- 

 tion dynamics of organisms living in this 

 zone. In conjunction with larval surveys, cir- 

 culation studies should be expanded during 

 the winter and spring along the Oregon coast 

 to improve the basis for predicting and 

 evaluating dispersal, primary productivity, 

 etc. A continuous program of temperature, 

 salinity, and current measurements are 

 needed of the nearshore currents during the 

 larval period from January through June and 

 particularly the timing and extent of the 

 March- April transition of the Davidson Cur- 

 rent. 



4. Short-term exposure of the larvae to en- 

 vironmental variables such as low salinity in 

 combination with varying temperature, food 

 density, etc. and subsequent transfer to op- 

 timum conditions for long-term observations 



in the laboratory are needed to properly 

 evaluate the effects of these factors. 



5. Detailed descriptions of the three- 

 dimensional composition of the associated 

 plankton communities are needed in terms 

 of the dominant species, size categories, and 

 diurnal variability. Investigations into the 

 contagious distribution of these organisms, 

 mechanisms of initiation and destruction, 

 are central to understanding prey-predator 

 interaction and attempts to model these 

 phenomena. 



6. Fine-mesh (0.165 and 0.053 mm) sampling 

 with the 0.2-m bongo nets should be used 

 concurrently with the 0.7-m bongo nets to 

 examine and answer the questions of food 

 composition and availability utilized by early 

 C. magister larvae. In particular, the inver- 

 tebrate component for both coarse- and 

 fine-mesh samples should be analyzed ini- 

 tially between contrasting years or areas of 

 larval abundance. The use of plankton pumps 

 may be more amenable in this case as fine- 

 mesh nets clog rapidly. 



7. The vertical distribution and diurnal move- 

 ments of C magister larvae throughout its 

 pelagic life is especially important in regard 

 to sampling variability, dispersal, and feed- 

 ing, and should be studied. Do most of the 

 older zoeal larvae, in fact, reside within a few 

 meters of the bottom in the shallow inshore 

 area? 



8. Laboratory studies should be undertaken to 

 analyze the phototactic behavior of the lar- 

 vae at various stages of development to gain 

 a better understanding of their diurnal 

 movements as may be modified by tempera- 

 ture, hunger state, presence of prey and pred- 

 ators, etc. 



9. A new approach is needed in the analysis of 

 larval gut contents. Biochemical techniques 

 of gut material may be used to identify food 

 organisms utilized by the larvae. Energy 

 budgets should be constructed to determine 

 minimum food requirements of the various 

 larval stages. Condition factors indicative of 

 the physiological well-being of larvae may be 

 used to evaluate good versus poor areas and 

 years of feeding. 



10. Potential predators that cooccur with C. 

 magister larvae should be identified and in- 

 gestion rates determined from field and 

 laboratory experiments in order to estimate 



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