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Fishery Bulletin 107(4) 
Figure 3 
(A) Linear catch per 1000 hooks (CPUE) trends for the commercial species 
in the Hawaii based deep-set longline fishery from the generalized additive 
models, 1996-2006: bigeye tuna ( Thunnus obesus ), blue shark (Prionace glciuca), 
mahimahi (Corypliaena hippurus ), sickle pomfret (Taractichtliys steindachneri ), 
skipjack tuna ( Katsuwonus pelamis), albacore (Thunnus alalunga), yellowfin 
tuna ( Thunnus albacares), striped marlin ( Tetrapturus audax), ono ( Acan - 
thocybium solandri), and shortbill spearfish (Tetrapturus angustirostris). (B) 
Annual catch per 1000 hooks (CPUE) and linear regression line for the non- 
commercial species from the observer catch data in the Hawaii based deep-set 
longline fishery, 1996-2006: escolar, (Lepidocybium flavobrunneum) , longnose 
lancetfish (Alepisaurus ferox), and snake mackerel ( Gempylus serpens). 
pelagic species and its predators (billfishes, sharks, and 
large tunas) have decreased concurrently. An increase 
in troll and handline CPUE for mahimahi has been 
observed in the Hawaii fishery since the 1980s (Boggs 
and Ito, 1993). Sickle pomfret and escolar are mesope- 
lagic species whose predators that include deep-foraging 
bigeye and albacore tunas, swordfish, and large sharks 
(Ward and Myers, 2005b). Snake mackerel inhabit both 
the epipelagic and mesopelagic depths and have many 
of the same predators as mahimahi in the epipelagic, 
and sickle pomfret in the mesopelagic depths. We have 
documented declines in relative abundance of bigeye 
and albacore tunas, striped marlins, shortbill spearfish- 
es, and blue sharks, all predators of these midtrophic 
level species. Further, on a Pacific basin scale, biomass 
of top-level predators, tunas and blue shark, has been 
estimated to be at 36-91% of the level they would be in 
the absence of fishing (Sibert et al., 2006). 
In a central Pacific EwE model, a top-down control 
was observed in the simulation (Kitchell et al., 2002; 
Fig. 3). When an increase in longline fishing was simu- 
lated, the biomasses of blue shark, large sharks, brown 
shark, bigeye tuna, yellowfin tuna, albacore, swordfish, 
blue marlin, and other marlins all declined; however, 
