FISHERY BULLETIN: VOL. 84, NO. 2 



Table 3.— Coefficient of variation (c.v., in percent) of mean catch by species-sex-age 1 

 group at Eureka and Monterey based on the two methods during 1982. 



1 Age-sex groups for which primary sampling units (landings) are >10. 



market categories which is of considerable economic 

 importance. 



COST FUNCTION 



The components c x and c 2 were estimated at 



Consider the cost function 



C = c x n + c 2 nm 



(25) 



where c x is the average cost (in minutes) per boat 

 trip due to transport, contact, and delay in making 

 a contact, c 2 the average cost in data collection 

 (identification of species, sex, length, otoliths, etc.) 

 per cluster within clusters per boat trip and C is the 

 total cost involved in visiting the primary sampling 

 units (boat trips) and collecting data from the n boats 

 with an average of m clusters per boat sampled. 

 Data collected at Tiburon by the California Depart- 

 ment of Fish and Game and the National Marine 

 Fisheries Service show that c = 111.80 min, c 2 = 



58.3 mm so that — = 2 apply. However, from more 



C 2 



recent studies conducted — = 3. 



c 2 



Activity 



Transport 



Contact 



Delay (off loading, etc.) 



Data collection 



Species 1 

 Sex, length 

 Otolith 

 Preparation time 



Percent 



50.0 



5.0 



13.0 



68.0 



Percent 



7.7 



5.8 

 10.8 



7.7 



32.0 



Mean (in minutes) 



81.7 



8.7 



21.4 



111.8 



Mean (in minutes) 



14.0 

 10.6 

 19.7 

 14.0 



58.3 



Excluding samples dominated by single species. 



Minimizing Equation (4) subject to Equation (25) 

 for the optimum allocation we have 



™ opt = 



(26) 



Table 4. — Optimum values of m for estimating species catch per cluster by categories 

 for different variance and cost ratios, 1978. 



'Code numbers of categories which are based on size, species and quality. 



414 



