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Another explanation offered by fishermen to explain the decline of bluefish is that striped 

 bass are preying on bluefish. However, bluefish are not a common prey of striped bass of any 

 age. In fact, the opposite is true. Juvenile bluefish prey heavily on many Anadromous species, 

 including striped bass, and once bluefish reach age 1 they compete directly with striped bass. 



For yet another theory, some fishermen have been suggesting that large numbers of bluefin 

 tuna have been attracted to the coast of North Carolina in recent years and that they prey on 

 bluefish. There are no feeding studies to support this hypothesis; and although bluefin certainly eat 

 bluefish, they primarily feed on menhaden and mackerel. It is not yet known whether the bluefin 

 abundance off North Carolina reflects an overall population increase or a localized event. 



While it is possible there is some new, unknown predation pressure on bluefish, there is a 

 lack of data to support this hypothesis. Moreover, the population dynamics of predators near the 

 top of the trophic pyramid are generally influenced more by prey abundance and availability than 

 predation. To address this issue adequately would require past and present feeding analyses of 

 potential bluefish predators, and analysis of the impact of predation on bluefish population 

 dynamics. 



The Subcommittee has also asked us to address environmental conditions such as water 

 temperatures that may be affecting the availability of bluefish, perhaps causing them to move 

 offshore. To address this issue, it would be necessary to determine if bluefish are more abundant 

 offshore. Unfortunately, fishery independent offshore surveys do not capture enough bluefish to 

 reliably estimate offshore abundances. Commercial landings have not declined as sharply as 

 recreational landings. Since most commercial harvest occurs in the EEZ, this suggests that 

 offshore abundance may not have declined as much as inshore abundance. This was supported at 

 Advisory Panel Meetings and Amendment 1 Scoping Meetings held during 1995, when many 

 fishermen stated bluefish were plentiful offshore. However, this could also be somewhat explained 

 by the fact that commercial gear is more efficient and mobile than most recreational gear. 

 Moreover, at a recent meeting of the ASMFC Bluefish Advisory Panel and the MAFMC Bluefish 

 Industry Advisors, many fishermen indicated that abundance was declining offshore and that they 

 were concerned about the condition of the resource. 



DRAFT:Testimony of John H. Dunnigan April 1, 1996 



Subcommittee on Fisheries, Wildlife and Oceans page 5 



