![]() The shark that went to Hawaii had a distinct diel pattern, with days spent at ~450–470 m and nights at ~250–300 m and almost no time in surface waters, corresponding with the diel migration of a specific portion of the deep scattering layer. The shark that moved south along the Baja Peninsula spent progressively more time in deep water but came to the surface daily. Movement patterns and shifts in vertical habitat and use are likely linked to shifts in prey availability and oceanography. Data collected indicate the potential for large-scale movements and the need for international dialogue in any recovery efforts.Ī long history of human interaction has resulted in the decline of many species of marine megafauna including turtles, tunas, cetaceans, rays and sharks ( Springer et al., 2003 Lewison et al., 2004 Marshall et al., 2006 Bradshaw et al., 2008 Dulvy et al., 2008 Croll et al., 2016 ISC, 2016). This list includes the second largest shark, the basking shark ( Cetorhinus maximus, Gunnerus, 1765), that can reach 12 m in length and is named for its habit of swimming slowly at the surface ( Compagno, 1984 Priede, 1984 Sims, 2008 McFarlane et al., 2009). Similar to many marine mammals, targeted fisheries for basking sharks in the Pacific Ocean ended decades ago ( McFarlane et al., 2009). ![]() ![]() However, while a number of marine mammal populations have rebounded ( IWC, 1998 Summarized in Carretta et al., 2009), there is no obvious increase in basking shark populations in the Pacific Ocean ( McFarlane et al., 2009). ![]()
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