Multivariate Empirical Contrasts Across 11 Northern Hemisphere Ecosystems

Multiple drivers of productivity in fishery ecosystems simultaneously interact to determine overall production levels.  These drivers reflect the triad of factors influencing fisheries production including fisheries, the environment, and trophodynamics.  Teasing apart the copious processes that dampen, amplify, modulate or enhance fisheries production requires a concurrent examination of a suite of indicators; a comparative approach to ecosystems also has merit in elucidating the relative dynamics of these processes.  Here we briefly describe and present a suite of biological indicators, loosely centered around fisheries production, as derived from standard fisheries independent and dependent surveys for 11 northern hemisphere ecosystems.  We also describe and present indicators that capture important fisheries drivers, environmental drivers, and trophodynamic drivers.  These represent common indicators that are beginning to be adopted more broadly in an international context.  More germane, we used a suite of multivariate (MV) statistical methods to explore relationships among the various biotic response indicators relative to the three types of driver indicators.  We also elucidated relative prominence among the drivers using these MV methods.  Further, preliminary examination of “tipping points” was explored.  Our results indicate that fishing pressure is typically a prominent feature and that in some ecosystems environmental perturbations can also be quite prominent, dependent upon local oceanographic conditions.  Yet we condition the interpretation of these generic findings in the context of the histories and nuances found in each ecosystem.  We discuss the ramifications for use in ecosystem-based fisheries management, with a consensus across ecosystems, MV methods, and indicators that a broad range of factors, based upon readily extant information, are worth regularly monitoring.