Fisheries conservation on the high seas: linking conservation physiology and fisheries ecology for the management of large pelagic fishes

Abstract

Physiological tools provide a mechanistic basis for understanding fundamental and applied ecology of tunas, billfishes, and pelagic sharks. In this synthesis, we review several templates for the interdisciplinary interactions between physiologists and fisheries scientists and highlight three areas of successful collaborations that directly benefit pelagic fisheries management.

Projections of climate‐driven changes in tuna vertical habitat based on species‐specific differences in blood oxygen affinity

“…Resource managers will benefit from information on the physiological mechanisms controlling habitat use when making decisions for tuna fisheries in a changing climate (e.g., Brill & Lutcavage, ; Horodysky et al., , ; McKenzie et al., ). Ocean warming and changes in the depths of the oxycline could have dire consequences for the movements, distribution, and abilities of tunas to withstand various levels of fishing mortality if the frequency of competitive interactions increases or prey have refuges from predation.…”

“…Recent observations show oxygen concentrations decreasing in the Eastern Tropical Pacific Ocean (Schmidtko, Stramma, & Visbeck, 2017;Stramma, Johnson, Sprintall, & Mohrholz, 2008), but there were no changes in oxygen concentrations in the model mean state for the region over the same period (Bopp et al, 2013). Cabr e, Marinov, Bernardello, and Bianchi (2015) Resource managers will benefit from information on the physiological mechanisms controlling habitat use when making decisions for tuna fisheries in a changing climate (e.g., Brill & Lutcavage, 2001;Horodysky et al, 2015Horodysky et al, , 2016McKenzie et al, 2016). Ocean warming and changes in the depths of the oxycline could have dire consequences for the movements, distribution, and abilities of tunas to withstand various levels of fishing mortality if the frequency of competitive interactions increases or prey have refuges from predation.…”

“…Mechanistic analysis helps reveal regional and temporal patterns in tunas' habitat and vertical movement (e.g., Horodysky, Cooke, & Brill, 2015;Horodysky, Cooke, Graves, & Brill, 2016;Lehodey et al, 2011). Physiological thresholds for blood oxygen binding have been mapped in the ocean as the P 50 depth (Mislan, Dunne, & Sarmiento, 2015).…”

Changing how we approach fisheries: A first attempt at an operational framework for ecosystem approaches to fisheries management

“…If a change in physiology were indicated by the diagnostics, one would need to proceed in a more bifurcated flow chart to evaluate whether the changes were declines or increases in various individual size and vital rate features (Figure ; Horodysky, Cooke, & Brill, ; Horodysky, Cooke, Graves, & Brill, ; Young et al, ). In effect, for each step in the flow chart, an evaluation of each subsequent metabolic process would result in either a change in SA model parameterization, a change in F (increase or decrease depending upon the direction of the physiological change), or if a decline, specific gear or area closure measures (Table ‐Physiology.VI).…”

Reflections and progress in conservation physiology

“…Thus, physiological knowledge can inform development of policy options for management of marine fishes (McKenzie et al ., 2016) including, for example, Pacific salmon (Patterson et al ., 2016) and pelagic fisheries (Horodysky et al ., 2016). Potential applications were also the core theme of the highly successful ‘Conservation Physiology’ themed 3 day symposium at the Society for Experimental Biology conference held in Brighton, UK last summer.…”