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taken within an area can serve to predict the health of stocks and possible 

 yields. However, the time requirements to gather the necessary volumes 

 of data are greater than the time necessary for a factory fleet to decimate 

 a stock. 



Figures concerning the number of vessels fishing in an area were ex- 

 tremely imprecise, depending on overflight information as well as reported 

 information that was often three years out of date.^''^) Such imprecision 

 had three important effects on assessments: 



• Only when stocks were recognized as threatened were scientists' 

 recommendations adhered to; 



• Calculation of catch/effort coefficients was based on information 

 thatwas known to be incorrect. 



• It became recognized that the time necessary to gather, collate, 

 and analyze catch and effort data exceeded the demands on the part 

 of managers to base their decisions on up-to-date information. 



In addition, assessment theories and procedures were founded on a 

 single-species approach that in and of itself was extremely complex. Intro- 

 duction of hundreds of factory vessels into Subarea 5 in the 1960s drove 

 assessments to consider entirely neglected species. Not only did infor- 

 mation needs increase by several orders of magnitude, but it soon became 

 apparent that fishing activities were having important effects on 

 stocks that had to be included in catch and effort analyses. 



Two examples serve to illustrate this point: 



• As it became clear that factory vessels were catching and keeping 

 quantities of species not being initially sought--bycatch--it was 

 realized that effort coefficients had to reflect the bycatch po- 

 tential of a chosen vessel. 



• Improved electronics increased the searching capacity of vessels. 

 Combined with skill of the skipper, it became very difficult to assess 

 the effects of effort undertaken with such aids as compared to effort 

 undertaken before such aids were developed. 



