Bycatch--the incidental catch of nontarget species--is a principal concern in marine conservation and fisheries management. In the eastern Pacific Ocean tuna fishery, a large fraction of nonmammal bycatch is captured by purse-seine gear when nets are deployed around floating objects. We examined the spatial distribution of a dominant species in this fishery's bycatch, the apex predator silky sh...

The influence of multiple anchored fish aggregating devices (FADs) on the spatial behavior of yellowfin (Thunnus albacares) and bigeye tuna (T. obesus) was investigated by equipping all thirteen FADs surrounding the island of Oahu (HI, USA) with automated sonic receivers (‘‘listening stations’’) and intra-peritoneally implanting individually coded acoustic transmitters in 45 yellowfin and 12 bi...

Research surveys attempting to use acoustic devices (i.e. echo sounders and sonar) to avoid bycatch and STFO are significantly hindered by the lack of any way to accurately verify what is actually under their vessel and being recorded on their instruments. Purse seine fishermen have a distinct advantage as they can refine catch estimates with every successful set and no doubt become quite profi...

Research surveys attempting to use acoustic devices (i.e. echo sounders and sonar) to avoid bycatch and STFO are significantly hindered by the lack of any way to accurately verify what is actually under their vessel and being recorded on their instruments. Purse seine fishermen have a distinct advantage as they can refine catch estimates with every successful set and no doubt become quite profi...

Tuna fisheries catch over three million tonnes of skipjack tuna (Katsuwonus pelamis) each year, the majority of which come from purse-seine vessels targeting fish associated with man-made fish aggregating devices (FADs). A significant challenge for fisheries management is to maximize the efficiency of skipjack tuna catches whilst minimizing the bycatch of small and immature bigeye (Thunnus obes...

Large reductions in the abundance of exploited land predators have led to significant range contractions for those species. This pattern can be formalized as the range-abundance relationship, a general macroecological pattern that has important implications for the conservation of threatened species. Here we ask whether similar responses may have occurred in highly mobile pelagic predators, spe...

We formulate and simulation-test a spatial surplus production model that provides a basis with which to undertake multispecies, multi-area, stock assessment. Movement between areas is parameterized using a simple gravity model that includes a "residency" parameter that determines the degree of stock mixing among areas. The model is deliberately simple in order to (1) accommodate nontarget speci...