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Competing pressures imposed by climate-related warming and offshore development have created a need for quantitative approaches that anticipate fisheries responses to these challenges. This study used a spatially explicit, ecological-economic agent-based model integrating dynamics associated with Atlantic surfclam stock biology, decision-making behavior of fishing vessel captains, and fishing fleet behavior to simulate stock biomass, and fishing vessel catch, effort and landings. Simulations were implemented using contemporary Atlantic surfclam stock distributions and characteristics of the surfclam fishing fleet. Simulated distribution of fishable surfclam biomass was determined by a spatially varying mortality rate, fishing by the fleet was controlled by captain decisions based on previous knowledge, information sharing, and the ability to search and find fishing grounds. Quantitative and qualitative evaluation of simulation results showed that this modeling approach sufficiently represents Atlantic surfclam fishery dynamics. A fishing simulation showed that the captain's decision-making and stock knowledge, and the distribution of fishing grounds relative to home ports controlled the landed catch. The approach used herein serves as the basis for future studies examining response of the Atlantic surfclam fishery to a nexus of simultaneous, complex natural and anthropogenic pressures, and provides a framework for similar models for other resources facing similar pressures.

The Atlantic surfclam (Spisula solidissima) fishery generates approximately USD 30 million in landings revenues annually, distributed across ports throughout the US Mid-Atlantic and Northeast. Overlap between areas of Atlantic surfclam harvests and offshore wind energy leasing make the fishery vulnerable to exclusion and effort displacement as development expands in the region. An existing integrated bioeconomic agent-based model, including spatial dynamics in Atlantic surfclam stock biology, heterogeneous captain behaviour, and federal management processes, was extended to incorporate costs and revenues for fishing vessels and processors and used to evaluate the potential economic effects of offshore wind development on the Atlantic surfclam fishery. Fishing activity and economic outcomes were simulated under different offshore wind energy development scenarios that impose spatial restrictions on Atlantic surfclam vessel fishing and transiting behaviour. Decreases in the number of trips and shifts in the spatial distribution of fishing effort reduced revenues for Atlantic surfclam fishing vessels and processors by ∼3–15% and increased average fishing costs by

Many “wicked” natural resources management problems today are utilizing more collaborative methods of decision making. Through involving stakeholders in decision-making, resource managers can induc...

Place: Lausanne Publisher: Frontiers Media Sa WOS:000517583500001; International audience; The eastern oyster once provided major societal and ecosystem benefits, but these benefits have been threatened in recent decades by large declines in oyster harvests. In many areas, recovery of oyster aquaculture faces significant societal opposition and spatial constraints limiting its ability to meet expectations regarding future food needs and provision of ecosystem services. In Virginia, oyster aquaculture has begun to expand, concurrent with an increase in subaqueous leased areas (over 130,000 acres of grounds are currently leased). Though private leases must in theory be used for oyster production, in practice, they can be held for other reasons, such as speculation or intentional exclusion of others. These factors have led to large variation over time and space in the use of leases in lower Chesapeake Bay; and privately leased grounds are now thought to be underutilized for oyster production. This research examined potential barriers to expansion of oyster aquaculture in Virginia. We first evaluated if a lack of space was limiting industry expansion and quantified temporal and spatial trends in the use and productivity of leases. Then, differences in used and non-used leases were investigated in relation to variables thought to be related to "not in my backyard" attitudes, congestion, speculation, local economic and environmental conditions. Finally, the performance of the Virginia leasing system was compared with those in other states along the U.S. East and Gulf Coasts. We found limited evidence for spatial constraints on aquaculture leasing, but strong evidence for social and regulatory inefficiencies. Although rates of lease use increased from 2006 to 2016, only 33% of leases were ever used for oyster production and about 63% of leaseholders reported no commercial harvests. Non-used leases tended to be smaller, and were found in more populated, high-income regions, consistent with both speculative and exclusionary uses. Virginia had the second lowest level of total production of cultured oysters per leased acre among the states on the East and Gulf Coasts of the United States. These results indicate that there is room for oyster aquaculture expansion in Virginia if societal, regulatory, and economic barriers can be reduced or if existing leased areas are used more efficiently.

Observed production sets in multispecies fisheries are affected by regulatory incentives influencing spatiotemporal fishing decisions. Rights-based output controls can promote selective fis...

Derelict fishing gear is a growing concern in many fisheries and coastal communities. Pots and traps are prevalent forms of derelict fishing gear with numerous documented harmful effects. In the Chesapeake Bay, US, a large blue crab (Callinectes sapidus) pot fishery produces high levels of derelict gear. From 2008 to 2014, 34,408 derelict pots were removed from blue crab fishing areas in Virginia. This research first evaluates whether observed increases in catch rates occurring contemporaneously with the removal program were the result of derelict gear removals. An econometric production model is then used to estimate marginal removal benefits and assess optimal removal levels. Fishing locations with removals during the removal program were estimated to have experienced increases in harvest per pot and harvest per trip of 22.35% and 34.68%, respectively. Optimal removal levels were found to depend on location-specific fishing effort, with high-effort areas yielding greater marginal removal benefits. Fishery productivity gains, though large, were found to last only one year following removals. Assuming a removal cost of $100/pot, the optimal level of removals was estimated to be over 7000 pots/year and would generate productivity gains of ~17–18%, yielding over US $3M in annual net benefits to the commercial fishery. Optimizing mitigation and management strategies for derelict fishing gear and marine debris requires quantitative assessment of the benefits and costs of alternative policy measures.

Local, national, and international efforts to address the issue of derelict fishing gear are often limited by resources and costs. Managers and policymakers have implemented various preventative, impact reducing, and curative measures to decrease derelict fishing gear abundance and impacts, but stakeholder support is essential for success. To identify stakeholder preferences and the most efficient measures to address the issue of derelict blue crab pots in Chesapeake Bay, we distributed a stated preference survey with a discrete choice experiment to 1,032 licensed commercial fishers in Virginia and received a 42% response rate. The choice experiment consisted of hypothetical scenarios with two alternatives that included a combination of derelict pot mitigation activities potentially paired with incentives, and a third alternative for maintaining the status quo. The probability that the average respondent would participate in derelict pot mitigation activities ranged from 0.46 (SE=0.07) for “Recycle at facility on land,” to 0.03 (SE=0.02) for “Pot modification.” Willingness to accept estimates were similarly variable, ranging from US $61 (SE=129) to participate in “Recycle at facility on land,” to US $1,449 (SE=359) for “Pot modification.” Non-monetary management incentives (e.g., bushel limit increase, pot limit increase, or season extension) generally did not induce participation in mitigation activities; however, heterogeneity observed in preferences of fishers could be used to target different segments of the population to participate in specific actions. Addressing the complex problems caused by marine debris, especially derelict fishing gear, is costly, and understanding stakeholder preferences and decision-making can help identify the most cost-effective solution.

Background Pop-up satellite archival tags (PSATs) are a valuable tool for estimating mortality of pelagic fishes released from commercial and recreational fishing gears. However, the high cost of PSATs limits sample sizes, resulting in low-precision post-release mortality estimates with little management applicability. We evaluate the performance of a lower-cost PSAT designed to enable large-scale post-release mortality studies. The tag uses solar rather than battery power, does not include a depth sensor, and transmits daily summaries of light and temperature data rather than high-resolution habitat profiles, contributing to a substantially lower per-unit price. We assessed the tag’s ability to detect mortality while also estimating the post-release mortality of juvenile (119–

As increasingly large extents of the global oceans are being managed through spatial measures, it is important to identify area characteristics underlying network distributions. Studies discerning spatial patterns in marine management have disproportionately focused on global networks. This paper instead considers the single country context of Japan to illuminate within-country drivers of area-based conservation and fishery management. A dataset containing potentially relevant socioeconomic, environmental, and fisheries factors was assembled and used to model prefecture-level counts of marine protected areas (MPAs) and territorial use rights for fisheries (TURFs) throughout Japan's waters. Several factors were found to significantly influence the number of TURFs in a particular area, whereas MPA patterns of use remain largely unexplained. TURFs are frequently noted as more suitable for managing fisheries of low mobility species and our analysis finds greater use of TURFs in areas that rely heavily on benthic catch. The number of trading ports was also found to be positively related to TURF distributions, suggesting economic infrastructure may influence the use of this fisheries management tool. In-line with global analyses, MPA patterns of use were not found to be significantly related to any of the potential explanatory variables after correcting for the number of statistical comparisons that were carried out. Differences in our ability to model the use of TURFs and MPAs may arise due to the narrower objectives associated with the former (e.g., income, employment) in comparison to the often broad and varied goals that motivate use of the latter.

A limited ability to target or avoid individual stocks complicates successful output management in multispecies fisheries. For vessels in these fisheries, reducing harvest of one species often requires simultaneous reductions in harvest of other stocks. The extent to which multispecies allocation targets can be met may depend critically on harvesters’ ability to substitute production across species. We introduce a measure of compositional control that captures the level of forgone production resulting from imperfect selectivity. This metric is then applied to data from the New England multispecies groundfish fishery and used to test for evidence of limited selectivity in the composition of individual vessel daily landings. Results indicate that increases in landings of one species generally require simultaneous increases in landings of other species — a finding that suggests difficulty in substituting production across groundfish species. Our measure is seen to vary widely through time as well as across vessels and species and may be affected by both environmental conditions and incentives created through management. The model developed here should hold value for managers and researchers seeking to assess interstock economic trade-offs in multispecies fisheries.

WOS:000502881300007; Beginning in the 1990's, Chile implemented an extensive Territorial User Rights for Fisheries (TURFs) network that now comprises nearly 1,000 TURFs. This network provides a rare opportunity to examine spatial and temporal trends in TURF use and impacts on surrounding open access areas (OAAs). In this analysis, landings of keyhole limpet (Fissurella spp.), kelp (Lessonia spp.) and red sea urchin (Loxechinus albus) were used to estimate catch-per-unit effort (CPUEs) and catch-per-unit area (CPUAs) indices inside and outside TURFs by fishing cove. For these species, CPUEs and CPUAs in 2015 were significantly higher inside TURFs. However, temporal trends analyzed with a linear mixed effects model indicate that CPUAs inside TURFs have been significantly decreasing since 2000 for keyhole limpet, red sea urchin and for loco (Concholepas concholepas), while in OAAs this measure only decreased for limpet. An elastic net regression was used to better explain catches in OAAs during 2015, including a variety of variables related to the characteristics and activity of proximal TURFs. Results indicate that exogenous factors unrelated to TURF management were the primary drivers of catches in OAAs during 2015 but that factors related to proximal TURFs appear to have a slight negative impact that grows over time. Collectively, these results indicate that while TURFs are associated with higher catch rates than surrounding OAAs, catch rates appear to be decreasing over time and, though limited, the impact of TURFs on surrounding OAAs may be negative. These findings suggest a need for a more nuanced and dynamic approach to spatial management on benthic resources in Chile.

An Agent-Based Model comprising a fish stock, a fishing fleet and a fish market is used to investigate the combined effects of environmental and market variability on the structure of a fishery. Over 15-year simulations, agents make daily fishing decisions and annual entry, exit, and investment decisions based on the fishery's past economic outcomes and their individual risk preferences and opportunity costs (e.g., an alternative source of income). Environmental variability is simulated through fishing success variability while market variability is simulated through changes in the elasticity of the demand curve (i.e., the responsiveness of market prices to changes in daily landings). Our findings indicate that changes in variability lead to changes in economic and biological conditions of the fishery by influencing the composition of risk preferences within the fleet. Counter to expectations, market stability did not dampen the negative impacts of environmental variability but rather stimulated over-investment and increased harvesting by a small number of risk-seeking fishers. Results from this research suggest that climate-driven increases in fisheries variability, coupled with increases in market integration that act to reduce local price signals, may lead to inefficient investments and reduced fishery resources.

While commercial and recreational fisheries are often considered to compete with one another, in the Atlantic bluefin tuna fishery along the U.S. east coast individual fishermen are permitted to fish either commercially or recreationally on a trip-by-trip basis. How these individuals choose to fish can affect whether the fishery adheres to domestic bluefin tuna regulations and could impact the United States' ability to comply with international management measures. We applied a contingent sequential stated choice survey to bluefin tuna fishermen to identify key factors governing disposition decisions, evaluate the impact of inertia (habit formation), and forecast future harvest patterns. Those who primarily fished recreationally demonstrated more opportunistic harvest tendencies than their commercial counterparts, who were more stable in their preference to harvest fish for sale. Simulations based on model results indicated that fish disposition (harvest commercially, harvest recreationally, or release) varied widely based on regulatory, individual, and fishery characteristics. Such results can help managers to forecast harvest patterns and adopt regulatory tools to ensure that harvest remains within prescribed limits.

Fisheries economists typically assume recreational anglers make decisions that maximize individual angler utility, which may depend on fishery and regulatory conditions. Under this framework, changes in regulations can lead to target species substitution by anglers in response to shifts in expectations of trip utility. A stated preference survey was developed and distributed to recreational cobia (Rachycentron canadum) anglers in Virginia to explore the effects of regulatory change on angler decision-making, species targeting, and resulting economic outcomes. The survey included a series of hypothetical choice scenarios, where respondents were asked to select their most preferred alternative after being presented with different fishing trips targeting cobia, red drum (Sciaenops ocellatus), or summer flounder (Paralichthys dentatus). Seven regulatory treatments of the survey were distributed, providing anglers a variety of species targeting tradeoffs. A mixed logit model was used to estimate angler preferences associated with hypothetical trip attributes and regulatory environment. Changes in angler welfare resulting from changes in cobia regulations were then assessed. Anglers were found to prefer targeting cobia to red drum or summer flounder under status quo management. Increases in catch, average weight of catch, and legal harvest of cobia were also found to provide anglers greater improvements in trip utility compared to increases in these attributes for trips targeting red drum or summer flounder. The economic effects of regulatory change were asymmetric because restrictive regulations were found to reduce angler welfare whereas liberalizing regulations had no significant effects. Increased availability of alternative target species was found to dampen the negative welfare effects of restrictive cobia regulations due to predicted target species substitution by anglers.

Pot fisheries occur worldwide with a significant proportion of the gear becoming derelict. Derelict pots induce detrimental ecological and economic impacts, and more recently were found to reduce blue crab harvests in the Chesapeake Bay commercial fishery. We simulated the presence of derelict pots near actively fished pots in seasonal field experiments to quantify the effect derelict pots have on blue crab harvest. Derelict pots reduced harvests by 30% during the summer, but not during the fall. Female blue crab capture rates were consistently lower when derelict pots were present; while capture rates of the less abundant males were not negatively affected by derelict pots. Variable responses to derelict pots may be due to seasonal differences in female and male blue crab behavior and movements. The costly effect that derelict pots have on harvest should be investigated in other pot fisheries to recognize the magnitude and mechanisms behind these impacts.

Every year, millions of pots and traps are lost in crustacean fisheries around the world. Derelict fishing gear has been found to produce several harmful environmental and ecological effects, however socioeconomic consequences have been investigated less frequently. We analyze the economic effects of a substantial derelict pot removal program in the largest estuary of the United States, the Chesapeake Bay. By combining spatially resolved data on derelict pot removals with commercial blue crab (Callinectes sapidus) harvests and effort, we show that removing 34,408 derelict pots led to significant gains in gear efficiency and an additional 13,504 MT in harvest valued at US $21.3 million—a 27% increase above that which would have occurred without removals. Model results are extended to a global analysis where it is seen that US $831 million in landings could be recovered annually by removing less than 10% of the derelict pots and traps from major crustacean fisheries. An unfortunate common pool externality, the degradation of marine environments is detrimental not only to marine organisms and biota, but also to those individuals and communities whose livelihoods and culture depend on profitable and sustainable marine resource use.