Identifying the potential for cross-fishery spillovers: a network analysis of Alaskan permitting patterns

Abstract

Many fishers own a portfolio of permits across multiple fisheries, creating an opportunity for fishing effort to adjust across fisheries and enabling impacts from a policy change in one fishery to spill over into other fisheries. In regions with a large and diverse number of permits and fisheries, joint-permitting can result in a complex system, making it difficult to understand the potential for cross-fishery substitution. In this study, we construct a network representation of permit ownership to characterize interconnectedness among Alaska commercial fisheries due to cross-fishery permitting. The Alaska fisheries network is highly connected, suggesting that most fisheries are vulnerable to cross-fishery spillovers from network shocks, such as changes to policies or fish stocks. We find that fisheries with similar geographic proximity are more likely to be a part of a highly connected cluster of susceptible fisheries. We use a case study to show that preexisting network statistics can be useful for identifying the potential scope of policy-induced spillovers. Our results demonstrate that network analysis can improve our understanding of the potential for policy-induced cross-fishery spillovers.

The small world of global marine fisheries: The cross-boundary consequences of larval dispersal

“…Network analysis has previously been applied to marine systems to describe the connectivity of plankton communities (19), local fishing communities (20,21) and marine reserves (16).…”

Defining the economic scope for ecosystem-based fishery management

“…For instance, the degree to which fishers are able and willing to substitute between fisheries in response to a policy shock could depend on the type of gear used, the fishing area, and the species harvested in other fisheries. Previous work has shown that fishers in Alaska are more likely to jointly permit in fisheries that share the same area and gear ( 35 ); thus, policies implemented in fisheries that do not share gear type and fishing areas with many other fisheries are not likely to generate much leakage. This is true of the rockfish and AFA pollock fisheries, both of which harvest with trawl gear in the Bering Sea and Western/Central Gulf of Alaska, respectively, where there are relatively few other fisheries that use the same gear.…”

“…In contrast, we estimate the scope of leakage (i.e., the set of impacted fisheries), changes in participation beyond the catch-share fishery, and changes in economic connectivity that coincide with catch-share implementation. To explore changes in economic connectivity between fisheries we use network analysis, which has been used in a variety of fisheries-related applications to understand system connectivity and complexity ( 22 , 33 – 35 ).…”

Changes to the structure and function of an albacore fishery reveal shifting social‐ecological realities for Pacific Northwest fishermen

“…At the network‐level used to assess aggregate patterns of fisheries connectivity, network edge density measured the proportion of links in a network that are present in relation to the maximum number of possible links. While edge density is a useful metric for describing interconnectedness, it does not account for the number of vessels driving these connections (Addicott et al., 2019). To assess weighted network connectivity, we relied on average node strength (sometimes referred to as average weighted degree centrality, see Kroetz et al., 2019 and Yletyinen et al., 2018) and average edge weights calculations.…”

“…Where acknowledgement of the human dimensions of marine resource systems does exist, fishers are often treated as uniform elements with little consideration of heterogeneity in goals, strategies and scales of operation (Fulton et al., 2011; Salas & Gaertner, 2004). Rather than existing as specialists, using specific gear types to target specific species, many fishers participate in multiple fisheries within and between years (Addicott et al., 2019). Decisions concerning how to allocate fishing effort are made in response to changes in species abundance and distribution (Cline et al., 2017; Finkbeiner, 2015), shifting regulations (Holland & Kasperski, 2016; Kroetz et al., 2019; Stoll et al., 2016) and market drivers (Kininmonth et al., 2017).…”