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^ 0.7 



i ° 6 



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 n 



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c 

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FISHERY BULLETIN: VOL. 84, NO. 1 



200 



50 



— I — 

 100 



— I — 

 150 



T 



200 

 Depth 



250 



— I — 

 300 



350 



400 



[ml 



Figure 5— The abundance of bottom fish (see text) in relation to depth. Solid line represents 

 fish densities with changing depth (measured in meters or fathoms). Error bars are standard 

 errors of means. Three 50-fathom depth zones are indicated, and mean fish densities within 

 these are shown as circled points. 



100 and 150 fathoms, and only 39,000 in the deep- 

 est (150-200 fathom) zone. Roughly 600,000 com- 

 mercially exploitable bottom fish are estimated to 

 comprise the deep-sea hook-and-line resource at 

 Johnston Atoll. Because the fish are spread over a 

 total habitat of 5,165 ha (Table 1), this corresponds 

 to average densities of 118 bottom fish/ha. 



Townsend Cromwell 



Anywhere from 2 to 4 lines were deployed while 

 fishing, resulting in an aggregate 41.8 line-h of 

 fishing effort spread over 23 vessel drifts. A catch 

 of 133 fishes (Table 3) produced an overall CPUE of 

 3.18 fish/line-h. Another 12 fish were hooked but lost 

 to sharks before landing. All species caught while 

 fishing were observed from the submersible with the 

 exception of the bramid, Eumegistus illustris. Deep- 

 water lutjanids predominated (69%), but substantial 

 numbers of serranids (22%) and carangids (8%) were 

 caught, a composition typical of tropical deep slope 

 fisheries worldwide (Talbot 1960; Ralston and Polo- 

 vina 1982; Munro 1983; Forster 1984). 



Species Composition By Location 



Examination of catch data suggested a difference 

 in species composition between upcurrent (sites 5 



Table 3. — Species composition of the bottom fish catch from the 

 Townsend Cromwell at Johnston Atoll. 



and 6) and downcurrent (sites 1-4) locations (Fig. 1). 

 Landings were pooled into these two classes, and al- 

 so by species category into Pristipomoides filamen- 

 tosus, P. zonatus, Epinephelus quernus, and "others". 

 The resulting 2x4 contingency table showed a lack 

 of statistical independence between locations and 

 species (x 2 = 22.36, df = 3, P « 0.005). Examin- 



150 



