Whale entanglements in fishing gear threaten whale populations, seafood production and long-term sustainability of commercial fisheries. While multiple mitigation strategies to reduce entanglements exist, there has been minimal consideration of the economic impact of these strategies. Here, we estimated retrospective losses to ex-vessel revenues for one of California’s most lucrative fisheries. Overall, we found fishery closures decreased ex-vessel revenue but regional differences in losses revealed interesting trends in the capacity for the fishery to recoup costs. For example, in the NMA, relatively small losses were predicted ($0.3 million in total) for the 2019 season despite an early closure to the season due to whale entanglement risk.
NMA fishers collectively were able to meet predicted revenue for the season despite a shortening of the fishing 2019 season. In the 2020 season however, the NMA did not experience disturbances due to whale entanglements but larger ex-vessel losses (of $3.9 million) were predicted. This suggests that other disturbances such as a delay to the season due to crab meat quality, lost fishing opportunity related to the COVID-19 pandemic, or other unknown factors, had an influence on ex-vessel revenue during the 2020 season. While most of the 2020 season landings in the NMA occurred before COVID-19 arrived in the US, there is evidence that prices in latter part of the season may have been depressed due to loss of export markets for live crab 39 .
In the CMA however, despite landing the majority of crab available during the 2019 season (see Fig. 2c), losses of $9.4 million were experienced across the fishery. This suggests that the closure to the fishery in the spring may have had some other effect on some other effect on income generation despite catch levels further than reducing total fishery catch (e.g. price, or disproportionate losses by those who would usually fish in the spring). In the 2020 season, whale entanglement risk substantially shortened the fishing season in the CMA, through a delay at the beginning of the season and an early closure in the spring. Estimated losses were largest ($14.4 million) during this season. It is likely that COVID-19 pandemic was also responsible for some of this estimated loss in the CMA in the 2020 season 39 .
Closures and other disturbances appear to have been less impactful in the NMA and high price for Dungeness crab may have contributed to the ability of vessels operating in the NMA to withstand disturbances (Supplementary Fig. 2). Prices were particularly high during the summer portion of the season in 2020 during which time the CMA was closed to Dungeness crab fishing (Supplementary Fig. 2). In previous seasons, e.g. during the HAB of the 2016 season, a shift in demand from closed to open management areas (from California to Washington) for Dungeness Crab has been observed40. A similar shift in consumers from the central California region to the Northern California region could explain this increase in price and contribution to revenues in the NMA. This unusual high price late in the 2020 season could also be explained by reopening of industries (e.g. restaurants) that closed early in the COVID-19 pandemic. The NMA did not experience closures due whale entanglement during 2020 and was predicted to have lower than average pre-season abundance (lower catch potential) during 2020 (see Fig. 2.b), while the CMA was predicted to have high catch potential for 2020 (Fig. 2.c).
The CMA also experienced high prices, including decadal high prices for crab during the November-December of the 2019 fishing season (Supplementary Fig. 2). However, losses observed overall across the two seasons suggest the fishery, unlike the NMA, did not get much overall benefit from the high price in 2019 or the high pre-season abundance of crab (i.e. catch potential) estimated for the 2020 season in the CMA. A number of factors may have contributed to a poor season in the CMA including catchability or biology of Dungeness crab as well as external factors such as the COVID-19 pandemic behavioral choice factors (e.g. deciding not to fish)38. Temporally shifting or reducing opportunity for participation through closed periods due to whale entanglement risk exacerbated other impacts on revenues in the CMA which were not as impactful on revenues in the NMA.
The high variability in estimated economic impacts per vessel reported here demonstrates that closures did not affect all vessels equally, similarly to impacts observed following a climate related harmful algal bloom in 2015 which were variable by vessel size and between communities38. This reflects the diverse nature of the Dungeness Crab fishery in behaviour and fishing strategy and highlights the importance of capturing impacts at finer scales than the fishery level alone. A behavioral choice model, for example one that incorporates location or fishing alternative choice given a closure41–43 would be a potential method to better understand how spatial management strategies affect fisher behavior and is recommended as a future analysis to assess trade-offs involving socio-economic risk.
Economic cost of mitigation
Many strategies that prevent fishery interactions with marine mammals exist, including gear reductions or modifications, depth limitations and dynamic or seasonal time-area closures15–21, 44. In the case of the California Dungeness crab fishery, only two options were enacted in the 2019 and 2020 seasons to mitigate against entanglements of marine life with Dungeness crab gear: delays to the start of the crab season in the winter and early closures in spring due to overlap with whale distribution in fishing grounds. These delays and closures can have differential impacts on the fishery as the fishing season is not heterogeneously prosperous. An example is that closures during the holiday season (Nov-Dec) when Dungeness crab is traditionally consumed can cause substantial lost revenue opportunity for fishers at a time when price and demand is highest28,40. Across the fishery, based on observed vessel level revenues during the 2011–2018 baseline period, vessels earned an average of 62.33% (SD 24.04) of annual ex-vessel revenue during the first month of the season (15th Nov-15th Dec for the CMA/ 1st Dec-31st Dec for the NMA). After April 1st, vessels earn on average earn 10.54 % (SD 18.9) of annual ex-vessel revenue. This average, based only on vessels that historically have actively participate past April 1st, (283 vessels in the NMA, 346 vessels in the CMA) rises to 20.36 % (SD 13.3) of ex-vessel revenue. Thus while the majority of the overall fisheries revenue is taken at the start of the season, an April 1st closure could still have a substantial impact on the revenues of active fishing vessels in the spring. The strong seasonal dynamics of the Dungeness crab fishery, largely driven by rapid depletion of legal sized crab, mean that the timing of management actions can have important impacts on fishing revenues. The number of vessels that participate in the spring is larger in the CMA than the NMA and thus could account for some of the difference in impacts observed between the two management areas.
A shift in effort for Dungeness crab fishing due to delays or closures can also impact revenues gained from participating in other fisheries. During the 2015-16 HAB event, estimates of revenue losses by crabbers participating in other fisheries were equal in magnitude to losses estimated from Dungeness crab revenues alone31. Timing of closures could have differential impact on vessels with different strategies. For example vessels that target crab throughout the season could be most impacted by early closures in the spring vs diversified vessels missing the window of opportunity for crab at the beginning of the season due to a delay. Determination of economic risk for the fishery, at a minimum, should consider timing of closures in addition to total revenue losses, in order to quantify losses that will be felt at the individual vessel level.
Our analysis does not capture finer temporal scale economic impact further than annual ex-vessel revenue which may have real-time impacts during periods when the fishery is closed, which occur despite delayed revenue accumulation suggesting lower or no overall impact. Closures to the Dungeness crab fishery during 2015-16 caused economic hardship throughout coastal communities, directly impacting the fishing industry, involving processors, market workers and deckhands and also impacting the hospitality, retail and tourism sectors28–30, 40. These economic impacts to communities were coupled with welfare issues related to economic loss, stress associated with finding adaptive strategies or employment, as well as cultural identity and removal of social activity within communities29. Impacts of lost fishing opportunity also depend on social vulnerability (e.g. levels of poverty, wealth education levels, labor force structure, population composition) and fishery reliance30. Socio-economic impacts from whale mitigation measures could permeate into communities further than our analysis (based on ex-vessel revenue only) conveys, and further investigation into these community level impacts is necessary to understand and sustain an equitable fishery supply chain even where there is no absolute revenue loss.
Balancing socio-economic impacts against whale entanglement risk is challenging given the legally protected status of whale populations. However, potential economic losses reported here should motivate the development of mitigation measures (through cooperative innovation between industry, researchers and managers) that allow fishery production to be optimized whilst ensuring successful whale protection. At present, entire management areas, which constitute large regions of the coast, are closed in response to whale entanglement risk in California. Investigating how to minimize the spatiotemporal footprint of closures, such as by defining high risk zones dynamically based on fine-scale information on whale density and fishing effort, could provide an alternative mitigation structure. This could better consider the economic and conservation trade-offs while still being sensitive to changing environmental conditions. The introduction of dynamic zone closures, often broadly referred to as dynamic ocean management, has been demonstrated to reduce risk whilst minimizing lost fishing opportunities21,45−47, especially when environmental variability is high or species have a dynamic distribution 48 . Moreover, analysis of policy instruments to reduce whale entanglements with the American lobster fishery on the US Northeast coast found that economic costs of risk reduction could be 20% lower when mitigation decisions considered fishing opportunity costs alongside non-monetary benefits (biological risk), compared to non-monetary benefits alone 46 . Dynamic zone closures requires spatially and temporally explicit information on whale density and fishing effort which can be costly to attain. However, revenue losses for Dungeness crab estimated here for the 2019 and 2020 seasons are on a par with losses experienced during the HAB period. During the delays to the 2016 fishing season an estimated $26.1 million was lost from ex-vessel revenues from all species that crab fishers target, including $13.6 million from Dungeness crab alone 31 , requiring $25 million in government aid. Whale mitigation under the RAMP regulation will potentially delay or close the fishery year after year with uncertain economic impact that cannot be sustainably resolved with government aid. Development of tools to mitigate against economic loss while achieving whale protection will be necessary to come to a sustainable solution. This can only be achieved by first including economic loss in risk assessments. Doing so may also provide balance to partnerships between fishery managers and fishers.
In any one season, the Dungeness crab fishery may experience disturbance from crab meat quality delays, HAB related food safety concerns, as well as natural fluctuations in crab availability and catchability. During the 2020 fishing season, disturbances also included the COVID-19 pandemic, which disrupted markets, supply chains and fishing activities. Many of these disturbances are unpredictable and add to the uncertainty of how an additional disturbance due to whale entanglement mitigation might impact the fishery economically. Moreover, in a changing climate, warm ocean conditions expected with higher intensity and frequency49 as are shifts in whale distributions in response to changing environmental conditions and changing distribution of prey11. The legal mandate of a whale entanglement mitigation program will result in future fishery delays and closures, as fishery managers try to prevent another serious spike in entanglements. In this fishery, current triggers to open and close are based on a range of factors, but ultimately depend on the number of whales present within a management region. Currently, a running average of 5 or more humpback whales over a one-week period within a region may cause a closure recommendation by fishery managers27. Surveying whale distribution and abundance is difficult because small boat and aerial surveys (considered ideal for a reliable snapshot) are extremely weather dependent. When no whale surveys are conducted a closure may be considered as a precautionary management measure due to unknown risk. Yet, the RAMP process lacks the socio-economic information needed to consider the socio-economic risk to the fishing community. Similarly, if more than one whale is entangled in a season that could trigger a closure of the entire fishing season again with no consideration of the socio-economic risk. Results presented here highlight that the economic effects and risk to fishing communities should be considered when designing whale entanglement mitigation programs. Regulators are obligated to protect Humpback whales, blue whales and Leatherback turtles using the best available science but have a number of regulatory options available to them which include depth restrictions, gear restrictions or modifications and fleet advisories27. Having this economic information will facilitate the ability of managers, as set out in the RAMP regulation (subsection d4)27, to consider the socio-economic impact if deciding between management measures that equivalently reduce entanglement risk.
We have used two fishing seasons as an example of the economic impacts of these new whale entanglement regulations which will be implemented each year going forward. This analysis, along with the community experiences documented following the HAB closures in 2015, provide an example of the economic impact of closures implemented on such spatial and temporal magnitudes. Synthesis of ex-vessel revenues is not a complete picture of the socio-economic impacts of regulations, but it provides a starting point for protecting both whales and fishing communities. While reported whale entanglements remain higher than pre-2014 totals, reported whale entanglements in California have declined markedly in the years following the 2014–2016 large marine heatwave (Fig. 1b). This is a success for this fishery and attributed to increased awareness, development of best practices for fishing gear and the mitigation program to protect whales. We now need to be successful at protecting and mitigating the socio-economic impacts to fishery participants and the fishing communities they support.