47 



The current conceptual model of recreational fishing form suggests 

 the following relations: 



a) net benefits per user depend, inter alia on total fishing 

 trips and average catch per trip; and 



b) stock size in any year depends on stock size in the 

 previous year, biological recruitment, and recreational 

 harvest. 



These basic relationships suggest that, at a minimum, the following data are 



needed for managing recreational fisheries according to the OSY concept: 



1) data on the total number of fishermen; 



2) data on the average number of fishing outings per 

 participant; 



3) data on the average catch per outing; 



4) data which would permit estimation of per capita or 



per user demand functions, including distance travelled, 

 average cost per trip, and number of trips to different 

 sites; 



5) socio-economic data on fishermen; 



6) population dynamics data. 



Information from items (l)-(5) could be used to estimate OSY for a particular 

 species. However, given the nature of recreational fishing, such data are 

 difficult and expensive to obtain. In contrast to the commercial fishery, 

 sports fishing is an exceedingly diffuse undertaking, since the individual 

 participants do not gather in a central place of exchange (markets in com- 

 mercial fisheries) which facilitates data collection. Sports fishermen do 

 not have a strong economic incentive to keep records, as do commercial 

 fishermen, and thus data gathered from sports fishermen must rely on their 

 ability to recall information. The accuracy of recall data is subject to the 

 desire to catch fish. Another difficulty with gathering data items (l)-(6) 



