Integrating what? Levels of marine ecosystem-based assessment and management

Abstract

Integrated assessment requires examination of factors across biological hierarchies, taxonomic groups, ocean-use sectors, management objectives, and scientific disciplines. The articles in this theme set represent attempts to clarify and elaborate upon what integrated assessments are, with a particular emphasis on how they are being implemented. The aim of this themed article set is to clarify the use of integratedassessment terminology and demonstrate, by presenting case studies, examples in which integrated ecosystem assessments serve as useful tools to implement ecosystem-based management (EBM) while also identifying challenges that must be overcome for this to succeed. In theory, EBM seeks to address the various natural and anthropogenic pressures faced by the key components of marine systems simultaneously. EBM also attempts to account for “cumulative impacts” that might otherwise be overlooked. Nascent attempts to implement EBM highlight the need—in practice—to address trade-offs across multiple objectives for a given system, in a coordinated and comprehensive manner. During the past decade, the discussion over EBM has shifted from “what is it and why should we do it” (Link, 2002; Browman and Stergiou, 2004, 2005) to “how can we do it and when can we operationalize it” (Arkema et al., 2006; Link, 2010; Berkes, 2012). Marine EBM (e.g. Levin and Lubchenco, 2008; McLeod and Leslie, 2009) and similar ecosystem-based efforts for more specific ocean-use sectors, such as ecosystem-based fisheries management (EBFM; e.g. Pikitch et al., 2004; Link, 2010) or integrated coastal-zone management (e.g. Cicin-Sain and Knecht, 1998; Moksness et al., 2013), have become the mandated approach to managing ocean resources. EBM is a major policy objective of many marine-oriented organizations—as is clear from a perusal of the strategic plans of organizations such as ICES, PICES, FAO, UNEP, and NOAA. The need for integrated assessments frequently arises in the context of discussions over implementing EBM. The term “integrated assessments” is perceived as mysterious and ultimately unhelpful because it suffers from a plurality of definitions and it is used in a multitude of contexts—i.e. it has high linguistic uncertainty. That is why we pose the question in the title of this introduction: what are we integrating and, hence, what are we assessing? Returning to the EBM context for sustainably managing marine resources, we note that there are, in fact, multiple levels at which an “ecosystem approach” can be adopted in practice. To illustrate, we focus on the fisheries sector. There are levels of application for EBM that focus solely on fish stocks, levels that focus on fish stocks but with ecosystem considerations incorporated, ecosystem levels that focus solely on the fisheries sector but for the full system of fisheries and stocks, and the full set of ocean-use sectors impacted by and impacting the fisheries sector (Table 1). For example, consider forage stocks such as small pelagic fish. For an ecosystem approach to fisheries (EAF) that takes a stock focus, one would need to consider the effects of environmental factors (e.g. temperature changes or NAO events) and ecological factors (e.g. predator removals or models of multispecies interactions) in addition to targeted fisheries removals to truly grasp what is driving the population dynamics of such stocks. Using the same type of focal species as an example, for EBFM that takes a system focus in the fisheries sector, one would have to consider not only the impacts of other factors on these forage stocks, but also the dynamics of these forage stocks on other parts of the ecosystem. For instance, there are seabirds or marine mammals that have some form of protected or conservation status and that are highly dependent on small pelagic forage fish. There are commercially targeted groundfish that are also major predators of these small pelagic forage fish. There are also multiple fisheries operating on both the groundfish and the small pelagic species. In such a case, clearly a more integrated, “bigger picture” evaluation of the