o 2 



70 



60- 



50 



< 5 



i^9 



LJ 40- 



^ o 30- 



^g 20- 

 z < 



!^ O 



10 



76 77 78 79 80 81 82 83 84 85 86 



YEAR 



Figure 4. Annual median trawl CPUE and Jolly abundance index (+2 standard errors) for Niantic River winter 



flounder from 1976 through 1986. Jolly index and CPUF, adjusted for fish 15 cm and larger in 1983-86 

 and shown by * and A, respectively. 



the catchability of marked and unmarked fish was not equal, sampling eirors of unknown magnitude 

 resulted. Jolly abundance estimates were also compared with those obtained using the Fisher- Ford and 

 Manly-Parr models in 1980 and as results were generally similar, the simpler and more powerful .lolly 

 model remained in use (NUSCo 1981a). 



The latest review (NUSCo 1986a) rigorously examined the model itself, assumptions, reliability of 

 results, and its particular application to the winter flounder population. The Jolly model has been criticized 

 because its flexibility is provided by many unknown parameters which must be estimated. These estimates 

 may be imprecise unless sampling intensity is relatively high (Cormack 1979; Buckland 1980; Nichols et 

 al. 1981; Hightower and Gilbert 1984). The review concluded that sampling intensity and recapture rates 



32 



