The heat is on: Gulf of Alaska Pacific cod and climate-ready fisheries

Abstract

Rapidly changing ocean conditions pose substantial challenges for coastal communities, fishermen, and managers. From 2014 to 2016, the Gulf of Alaska (GOA) experienced a marine heatwave and corollary decline in Pacific cod (Gadus macrocephalus). Here, we explore the 2020 closure of the directed Pacific cod federal fishery in the GOA as a case study of the needs and opportunities for managing fisheries in the context of environmental change. We build on climate-ready fishery research and conversations with experienced commercial fishermen, including Alutiiq fishers, and fishery managers to: (i) discuss ecosystem-based management in Alaska, (ii) explore early warning signs and management challenges preceding the decline of Pacific cod, (iii) recommend tools to enhance adaptive capacity in fishery management. We conclude that a strong foundation of science-based management that incorporates ecosystem information and multiple ways of knowing, increased monitoring and evaluation of indicators, and new tools for managers to respond and adapt will be essential to sustainable fishery management. New mechanisms highlighted in this essay include: a GOA Fishery Ecosystem Plan, climate risk and vulnerability analyses, habitat protections, and the development of original metrics, such as food web production or function targets to inform stock assessments and fishery management.

adaptive management, climate-ready fisheries, indicators, marine heatwave, Pacific cod

Introduction

Pacific cod (Gadus macrocephalus) is a fast-growing groundfish and key demersal predator in the Gulf of Alaska (GOA) and Bering Sea (Anderson and Piatt, 1999; Urban, 2012; Barbeaux et al., 2019). Cod is also an important subsistence species and has been harvested in the GOA for at least 4500 years (Maschner et al., 2008; Barbeaux et al., 2019). Pacific cod are essential to the Alaskan ecosystem, economy and culture, and the GOA is currently home to some of the highest value and largest volume ports in the world (Fissel et al., 2019). GOA Pacific cod production volume averaged nearly 150 000 t from 2011 to 2016 (Barbeaux et al., 2019), and the cod fishery typically accounts for roughly one-third of the value of groundfish harvest in the GOA (Barbeaux et al., 2019, 2020; Fissel et al., 2019). In 2017, GOA Pacific cod first wholesale production value was at a 12-year peak, worth an estimated $510 USD million (Fissel et al., 2019). GOA Pacific cod is also a significant protein source for human consumption internationally; the majority of products produced from GOA cod are exported, and 18% of global cod harvest in 2016 came from the GOA (Fissel et al., 2019).

In recent years, this important and productive fishery system has come crashing down around fishermen, managers, and communities. In fall 2019, the National Marine Fisheries Service (NMFS) was forced to close the 2020 directed federal Pacific cod fishery due to low biomass. Though managers never determined that the stock was below the overfished level (OFL; B_17.5%; spawning stock biomass percentage relative to unfished level), it came precariously close in 2020 at B_17.6% (Barbeaux et al., 2019). The cod decline occurred rapidly, from a 12-year peak in value in 2017 to full closure in 2020 (Fissel et al., 2019). The reduction in biomass and closure of the directed federal fishery left cod fishermen in the GOA without their primary source of income and with limited alternatives.

The dramatic declines in Pacific cod biomass and productivity were linked to a series of warm years and marine heatwaves beginning in late 2013 (Barbeaux et al., 2019; Cheung and Frölicher, 2020; Laurel and Rogers, 2020). From the winter of 2013/2014 to 2014/2015, the northeast Pacific experienced the greatest marine heatwave recorded since 1880 (Di Lorenzo and Mantua, 2016; Laurel and Rogers, 2020). Warm conditions returned to the GOA, and in 2019 another, shorter-lived marine heatwave emerged in the North Pacific (Cornwall, 2019; Cheung and Frölicher, 2020). Marine heatwaves are linked with decreases in nutrient supply, net primary production and community production in the northeast Pacific (Whitney, 2015; Yang et al., 2018, 2019; Cheung and Frölicher, 2020). Marine heatwave events globally have increased in frequency, duration, and intensity in response to ocean warming resulting from increased anthropogenic emissions of greenhouse gases (Oliver et al., 2018; IPCC, 2019; Cheung and Frölicher, 2020).

The response of Pacific cod to anomalously warm conditions and weakened nutrient transport in the GOA was rapid and extreme. From 2015 to 2017, GOA Pacific cod biomass and abundance declined by 58 and 71%, respectively (Barbeaux et al., 2019). The hypothesized mechanism of the cod decline was twofold. First, the availability of suitable thermal habitat for hatching GOA Pacific cod was significantly reduced as a result of warm conditions throughout the water column (Walsh et al., 2018; Laurel and Rogers, 2020). Pacific cod hatch success declines substantially in water above or below 4–5°C, and one important characteristic of the recent GOA marine heatwaves was the presence and persistence of warm waters at depth (Laurel and Rogers, 2020). Second, the growth potential of maturing cod was reduced due to increased metabolic demand and reduced prey supply caused by warmer temperatures (Barbeaux et al., 2020). Bioenergetic models by Barbeaux et al. (2020) confirmed that Pacific cod foraging demand was elevated above long-term mean estimates (1978–2018), peaking in 2015. Similarly, Pacific cod body condition from the bottom trawl survey was lowest in 2015, indicating reduced metabolic efficiency (Barbeaux et al., 2020).

Pacific cod have historically exhibited ups and downs. The Aleut word for Pacific cod, atxidax, translates to “the fish that stops”, highlighting that Pacific cod stocks historically underwent significant population fluctuations (Maschner et al., 2008; Betts et al., 2011; Barbeaux et al., 2019, 2020). However, the bust the stock experienced in late 2013 was unprecedented in terms of what one fisherman referred to as the “severity of the decline on the fishing grounds”. Another fisherman interviewed said they realized there “were new mechanisms at play” when the temperature stayed warm, and they stopped catching younger fish.

As a species with limited capacity to adapt to increasing temperatures at certain life stages, GOA Pacific cod are an important early warning sign and indicator of the far-reaching socioeconomic and biological impacts of warming ocean temperatures. Fishermen are still struggling with the fallout from the closure and are working to diversify their fishing businesses to stay afloat. This essay is intended to identify the ways in which the current management framework in the GOA was prepared—and unprepared—to detect and respond to the impacts from the marine heatwave and to evaluate novel climate adaptation pathways that support ecosystem and fishery sustainability. To that end, this case study: (i) discusses the current fishery management context in Alaska, (ii) explores early warning signs and management challenges preceding the collapse of the GOA Pacific cod stock, and (iii) identifies tools that could be employed to enhance adaptive capacity and climate resilience in the Pacific cod fishery specifically and fishery management more broadly.

Methods

Following a series of informal dockside conversations in Kodiak, AK, four semi-directed interviews (Bernard, 2006) were conducted with two commercial fishers in the GOA as well as two Alutiiq fishers and members of regional Tribal Councils in the summer of 2020. Respondents were non-randomly selected based on GOA fishing experience (>30 years) and/or Indigenous community affiliations. Respondents were asked three open-ended questions (Bernard, 2006) related to the GOA Pacific cod collapse: (i) experience or perception of early warning signs of Pacific cod decline, (ii) personal or community impacts of GOA Pacific cod fishery collapse, (iii) recommendations for how to improve fishery management in a changing climate. Notes were taken during the interviews. While this “food for thought” essay is not intended to present new data, the authors chose to include interview excerpts in the essay to construct a more layered and diverse discussion of the Pacific cod issue.

Management context

GOA Pacific cod is managed under both state (0–3 nautical miles offshore) and federal jurisdiction (3–200 nautical miles; Exclusive Economic Zone). This essay focuses on the federal fishery management of Pacific cod, which is governed by the Magnuson–Stevens Fishery Conservation and Management Act (Magnuson–Stevens Act). The statute creates eight regional fishery management bodies (Councils) that develop Fishery Management Plans (FMPs) that are, in turn, approved and implemented by the NMFS within the National Oceanic and Atmospheric Administration (NOAA). By law, FMPs must include conservation and management measures that are “necessary and appropriate for the conservation and management of the fishery to prevent overfishing and rebuild overfished stocks, and to protect, restore, and promote the long-term health and stability of the fishery” [16 U.S.C. 1853(a)(1)(A)]. These measures can include, for example, limits on types of gear, areas available to fisheries, and time constraints.

Pursuant to the applicable FMP, managers establish three primary harvest reference points for each target stock: the OFL (overfishing occurs when exceeded), the Acceptable Biological Catch (ABC; the upper limit of acceptable harvests from a biological perspective) and Total Allowable Catch (TAC or catch limits, which must be equal to or less than the ABC) for each fishery (Witherell et al., 2000). If the Pacific cod fishery drops below the OFL (B_17.5%), a rebuilding plan would be established that could include more constraining rules for the directed harvest of Pacific cod and more restrictive bycatch limits for Pacific cod in fisheries targeting other species. This tiered approach overall is intended to ensure that mechanisms are in place to protect stocks against modelling, environmental, and management uncertainties (Witherell et al., 2000; Kvamsdal et al., 2016).

Additional ecosystem-based harvest control rules, which limit catch when the biomass of a target stock falls below an identified reference point, are in place for some species. Pacific cod is subject to a harvest control rule that requires the fishery to be closed when biomass drops below B_20%. This rule is intended to ensure that there is sufficient forage for Steller sea lions (McBeath, 2004). The rule was established in the early 2000s but not invoked until 2020 when Pacific cod biomass was estimated to be below the B_20% threshold (Barbeaux et al., 2019).

In the North Pacific, the TAC setting process and relevant management measures are also informed by the annual Ecosystem Status Report (ESR) developed by members of the Integrated Ecosystem Assessment Programme within NOAA. The ESR provides information about a range of indicators from physical oceanography and climate to predator and forage indices to human dimensions (Siddon and Zador, 2019). Indicators tracked in the ESR provide contextual ecosystem information for the North Pacific Fishery Management Council (NPFMC) and its technical expert teams preceding the review of groundfish and crab harvest recommendations. There are several tools used in other regions of the North Pacific, including Fishery Ecosystem Plans and an overall cap on groundfish harvest, which are not currently in place in the GOA.

Trouble ahead

Despite a progressive ecosystem-based fishery management (EBFM) programme in Alaska (Levin et al., 2009; Kvamsdal et al., 2016), the challenges posed for Pacific cod by the 2014–2016 GOA marine heatwave created the ultimate “stress test” (Barbeaux et al., 2020) for federal fishery managers and fishermen. Hindsight allows us to spotlight potential warning signs and data gaps that, while difficult to interpret as individual indicators, collectively signalled trouble for the GOA Alaska Pacific cod fishery by late 2017 (Figure 1):

Figure 1.

Timeline of Pacific cod biomass estimates, management, and environmental indicators, 2013–2020.

• Weakened nutrient transport—Anomalous south winds in the winter of 2013/2014 weakened nutrient transport in the eastern North Pacific, which resulted in a substantial decrease in phytoplankton biomass and record-low chlorophyll levels (Whitney, 2015). Weakened nutrient transport and warming conditions have since been linked to reduced forage availability for piscivorous seabirds, groundfish, and marine mammals in the GOA (Savage, 2017; von Biela et al., 2019; Piatt et al., 2020).

• Unusual mortality events (UMEs)—A number of species across trophic levels declined during or shortly after the warm conditions in the GOA in 2014–2016. From the summer of 2015 to the spring of 2016, an estimated 1 million common murres (Uria aalge) died as part of an UME in the Pacific Ocean. Three-quarters of the documented mortalities occurred in the GOA (Piatt et al., 2020). Fin whale (Balaenoptera physalus) and humpback whale (Megaptera novaeangliae) die-offs were identified as an UME from 2015 to 2016 (Savage, 2017), and most recently an estimated 382 grey whales stranded along the coastlines of the western United States, Canada, and Mexico from 2019 to October 2020 (Siddon, 2020). Preliminary findings from whale necropsies suggest emaciation was a factor contributing to mortality for some individuals (NOAA Fisheries, 2021). A fisherman we spoke with as part of this project said that the early seabird and whale die-offs in 2015 and 2016 indicated a GOA system under stress.

• Extended warm conditions in the GOA—The 2015 ESR Report Card stated the GOA was characterized by warm conditions and noted that the Pacific Decadal Oscillation had reached the highest winter value on a record extending back to 1900 (Zador, 2015). In 2016, the ESR summary presentation given to the NPFMC stressed the “continuation of warm conditions” and “reduced productivity” in the GOA (Zador and Siddon, 2016).

• Indications from the fishery—In interviews conducted as part of this essay, fishermen reported they were seeing signs of a change in the ecosystem state and Pacific cod as early as 2015. Public testimony from fishermen at the December 2016 NPFMC meeting noted 2016 “was a very odd year in terms of the fisheries in the GOA because it was the warmest water temperatures we’ve ever seen…The spawn for cod really never happened. At least for trawlers, they never reached their A season [cod] allocations”. At the same Council meeting, another fisher testified, “Things have changed with the warming oceans here. For the first time in a long time the bigger fish disappeared”. Fishermen interviewed for this essay also reported they recall Pacific cod just “weren’t available closer to shore where they had been historically”, they “were not seeing the smaller fish”, and “body conditions were poor”.

• High historic fishing mortality rates and uncertainty—The GOA Pacific cod stock assessment model was changed substantially in 2016, and at that time assessment authors identified structural errors associated with ageing and natural mortality estimates in earlier models (Barbeaux et al., 2019). Retrospective analyses indicated that fishing mortality had been exceeding target reference points (ABC control rule) from 2005–2011 to 2015–2017. Similarly, biomass had historically been overestimated and had been below the B_35% management target from 2008 to 2009. Current Pacific cod models suggest that from 2008 to 2017, there was a decline in recruitment coupled with increased catches (Barbeaux et al., 2019). A similar scenario played out in early 1990s with the collapse of Northwest Atlantic cod (Gadus morhua), when modelling uncertainties, high fishing mortality rates, reduced recruitment and significant environmental changes were identified as drivers of Northwest Atlantic cod declines (deYoung and Rose, 1993; Myers et al., 1996; Fu and Fanning, 2004).

This uncertainty was exacerbated by the lack of a trawl survey in 2016. The Pacific cod stock assessment is informed by two key surveys: the GOA biennial trawl survey (odd years only) and the Alaska Fisheries Science Center (AFSC) longline survey (annual). The annual longline survey is less selective of smaller fish, and the biomass estimate of Pacific cod from the survey (Relative Population Numbers) did not exhibit a marked decline until 2017 (Barbeaux et al., 2019). As such, fishery-independent data, especially for younger cod cohorts, were limited in 2016 without the bottom trawl survey.

Uncertainty in stock assessments is more critical for species that are harvested at or above their TAC levels. Fisheries (such as GOA Pacific cod) prosecuted at maximum levels have a reduced buffer against stock assessment uncertainty and environmental perturbations. In most years from 2003 to 2015 (excluding 2006–2007), the total federal and state Pacific cod catch exceeded the federal TAC for Pacific cod by an average of 19% (Barbeaux et al., 2019). TAC overages in GOA Pacific cod were a result of the mixed state and federal fishery management TAC setting process as opposed to commercial fishery overharvest.

Moving towards climate-ready fisheries

Federal fishery management in Alaska is often considered to be at the forefront of sustainable- and ecosystem-based approaches (Marshall et al., 2018; Holsman et al., 2020). Certainly, managers in the region have taken very important steps, including development of the Bering Sea and Aleutian Islands Fishery Ecosystem Plans (FEPs), creation of an ecosystem vision statement, and implementation of the Arctic FMP. Nonetheless, the current EBFM framework in Alaska was not established to address climate change directly (Holsman et al., 2020). Current EBFM measures may help to buffer against negative changes associated with climate change in the short term; however, simulations under two future emissions scenarios predict spawning stocks will on average decline by 47–70% for pollock (Gadus chalcogrammus) and 23–41% for Pacific cod by end-of-century (2075–2100; Holsman et al., 2020). Managers must continue to explore progressive climate adaptation measures in the short and long term to sustain ecosystem productivity and the socioeconomic systems that rely on these services (Pinsky and Mantua, 2014).

To effectuate that change, it is important to incorporate climate-ready fishery tools that prioritize socio-ecological equity, resilience, and sustainability in the context of the rapid changes and increased uncertainty associated with climate change (Kang et al., 2006; Pinsky and Mantua, 2014; Wilson et al., 2018; Holsman et al., 2019; Karp et al., 2019; Young et al., 2019). A scientifically based approach that considers human dimensions and ecosystem function and incorporates multiple ways of knowing will best enable communities and managers to adapt to changing conditions. Events surrounding GOA Pacific cod point to the dual challenges that climate change will pose for fish stocks and managers as they respond to environmental changes. More specifically, the Pacific cod decline makes apparent several advances that could be implemented to better prepare for coming changes. Increased monitoring, use of indicators and forecasts, incorporation of multiple ways of knowing, and development of adaptive management tools will help managers be more responsive to new information and changing environments.

Monitoring

Accurate and ongoing information about individual stocks and the broader ecosystem is a critical foundation for fishery management in uncertain conditions and can help managers detect and anticipate change. On the whole, fishery management in the North Pacific is data-rich, yet gaps remain. Had a GOA bottom trawl survey been run in 2016, it is likely that the lack of smaller fish and poor recruitment would have provided an earlier and/or stronger signal, thereby giving managers and the fishing industry more time to adjust.

Managers must have more information, not less, which means that the federal government must prioritize funding for surveys. Unfortunately, the opposite has been happening, which has left regional fishery managers to try to prioritize survey needs amidst increasingly limited funding and shifting distributions and productivity for some commercial species. In August 2020, the NPFMC Science and Statistical Committee conducted a joint workshop with the AFSC to discuss research survey planning, prioritization, and funding challenges in upcoming years. Given limited resources, the conversations regarding GOA Pacific cod centred on the trade-off of reducing survey coverage at deeper stations rather than reducing station density. But there is no one-size-fits-all answer, and research indicates that Pacific cod in the GOA tend to move deeper in warmer years (Yang et al., 2019). It will be more challenging to track depth distributions shifts for some groundfish species if the deepest strata are no longer sampled in the GOA. Increased funding is key; until this happens, however, managers and communities must think collaboratively and creatively (as with the 2020 workshop) about maintaining data integrity and minimizing uncertainty in the face of limited resources and changing ocean conditions. Collaborative research with fishing industry, Tribes and Indigenous and coastal communities may reduce data collection costs and increase communication with stakeholders.

In addition to fish surveys, it is imperative that managers also are provided information about other aspects of the ecosystem. As the ocean continues to warm and becomes more acidic, trophic energy flows and food web dynamics are likely to shift, and new ecosystem states may develop (Grimm et al., 2013). Species distribution and productivities will change (O’Connor et al., 2009; Cheung et al., 2013; Nagelkerken et al., 2017; Ullah et al., 2018; Free et al., 2019). The relevance of historical time series to future scenarios may also change (Holsman et al., 2020). As such, continuing regular ecosystem assessments and annual surveys, and expanding to new areas when possible, will be integral to tracking and identifying ecosystem changes and early detection of tipping points. Ensuring connections between stock assessments and ecosystem information is essential, acknowledging that some environmental indicators may be informative to key stock assessment components such as recruitment and mortality (Punt, 2011).

The GOA is a well-monitored ecosystem relative to other regions that also support important fisheries. As conditions change, surveys become even more critical, and effective monitoring will be a key part of adaptability in many regions globally (Barange et al., 2018). Yet there are challenges associated with monitoring capacity, coordination when a fishery or ecosystem spans multiple jurisdictions; monitoring in all regions must be paired with research to understand the mechanisms of climate impacts on fish stocks and possible adaptive solutions.

New technologies exist that may reduce some of the costs associated with gathering ecosystem information in the long term. Moored and quasi-static unmanned nodes or operations can collect long-term oceanography data. In addition, progressive technologies, like Autonomous Underwater and Surface Vehicles (AUVs; USVs), Unmanned Aerial Vehicles and moored and drifting data collection systems, can be employed (Zolich et al., 2019). For example, the ArcticABC project is utilizing a combination of new moored and mobile autonomous instrumentation to record and collect data on under-ice Arctic ecosystems (Zolich et al., 2018, 2019). Electronic Monitoring systems can also be used to track species composition and bycatch data in some fisheries. One consequence of new sensor technologies in marine research is the increasing demand for high data-rates to process large amounts of ecological data efficiently. Promising new fields to process big data include Machine Learning and Deep Learning, which are broadly defined as dynamic modelling and/or applied algorithms used to solve complex processing problems in big data sets (Beyan and Browman, 2020). The trade-offs of using new technologies must be carefully evaluated as research platforms change. In the end, maintaining current and/or expanding future ecosystem monitoring is expensive; however, the longer-term socioeconomic and cultural costs of failing to detect major marine ecosystem changes as early as possible will be much greater.

Indicator evaluation

In addition to gathering needed information from monitoring and surveys, clear mechanisms, and insertion points for that information into decision-making processes are necessary. One way to start this process is through a comprehensive survey and monitoring scheme that supports the development of socio-ecological and socioeconomic indicators. In this context, indicators are typically quantitative measurements of ecosystem, economic, or species attributes used to assess specific to broad aspects of ecosystem status (Cury and Christensen, 2005; Reed et al., 2017). Indicators have the potential to bridge the gap between data derived from monitoring and management responses.

There are a number of benefits associated with identifying environmental, functional, and/or species-specific indicators as proxies for the overall health of a coupled environment–human system. Using targeted indicators as a proxy for overall ecosystem health and function can be both a cost- and time-efficient measure when the underlying mechanisms are well-understood (Carignan and Villard, 2002). One example is the Pacific Fishery Management Council’s annually updated “stoplight table” in the ESR, which characterizes ocean conditions as they relate to juvenile salmon survival along the US west coast (CCIEA, 2020). The need for indicators is particularly relevant in biodiverse, species-rich systems like the GOA, where it is not possible to monitor all taxa and trophic interactions (Lindenmayer, 1999). Indicator-based management can be used to achieve specific management objectives, including identifying thresholds and tipping points, assessing the efficacy of management measures and detecting both early-stage and long-term ecological changes or shifts (Siddig et al., 2016).

The current Pacific cod stock assessment takes steps towards the development of environmental indicators, including using a bottom temperature and marine heatwave intensity index (Barbeaux et al., 2019). Seabird forage success is another potential environmental indicator of available forage (Barbeaux et al., 2020; Piatt et al., 2020). As our understanding of the mechanisms behind these relationships is strengthened these, and other applicable environmental indices can become climate-derived covariates in future stock assessments.

Catch per unit effort (CPUE) indices may also elucidate trends in Pacific cod biomass estimates and spatial variability. The Pacific cod fishery is a multi-gear fishery, with bottom trawl, longline, pot, and jig components. CPUE and fishery selectivity (the probability of catching fish) varies by gear type and region and can exhibit hyper-stability (Fauconnet and Rochet, 2016; Okamura et al., 2018; Barbeaux et al., 2019; Holsman et al., 2020), which can render CPUE indices challenging to interpret. For instance, CPUE in the western GOA bottom trawl fishery declined as early as 2013 whereas the western GOA pot fishery CPUE did not show a decline until 2017 (Barbeaux et al., 2019).

Fishermen reported that jig and inshore fisheries (some managed by the State) provided an early indication that Pacific cod distribution and biomass were changing during and after the marine heatwave. However, data are more limited for these sectors due to lower observer coverage, and there are fewer mechanisms for the incorporation of state and jig fishery CPUE information in federal fisheries management. CPUE indices are often incorporated in stock assessments (Carruthers et al., 2011), but for multiple-gear type fisheries that exhibit a high degree of spatial variability, the inclusion of fishery-dependent data in the stock assessment is not straightforward. In this example, Pacific cod fishery management would benefit from an enhanced understanding of CPUE indices by gear type as well as additional environmental indicators, such as heatwave intensity or forage availability (Barbeaux et al., 2019).

Several regional fishery management councils have used ecosystem indicators in management at some level, and these indicators are often linked to ESRs produced by NOAA’s Integrated Ecosystem Assessment teams. Koehn et al. (2020) reviewed ten case studies and determined that nearly all fisheries management analysed used ecosystem indicators as part of implementing EBFM; however, there were relatively few examples where indicators were directly linked to prioritized objectives or used to inform management strategies themselves. This suggests that other Councils could benefit from the use of targeted ecosystem indicators as well as the use of indicators in stock assessments and management decisions (Koehn et al., 2020).

This recommendation comes with an important caveat: not all data (social, cultural) align well with traditional quantitative indicator analyses. Qualitative data can serve as a meaningful metric for marine systems or communities not well-described by quantitative data (Carruthers and Neis, 2011; Barclay et al., 2017). Particularly for a coupled human-ocean system, there are important data sets that do not fit within the bounds of quantitative measurements, and it would be an error to assume that the impacts on communities can be fully measured by current quantitative metrics. It is important to recognize these limitations and work towards including qualitative information and observations in these assessments in addition to more traditional quantitative indicators.

Multiple ways of knowing

GOA fishery management will be improved by expanding data sources and types, including Traditional Knowledge (TK) and Local Knowledge (LK). TK and LK are important sources of information about what is happening on the water and in communities, which can in turn inform fishery managers as they navigate a changing marine ecosystem (Stephenson et al., 2016). In addition, TK can be a critical avenue for detecting major shifts in ecosystem function and trophic structure at longer time scales that may vary from more standard quantitative indicators (Raymond-Yakoubian et al., 2017).

TK is defined as a living body of knowledge acquired and utilized by Indigenous communities and individuals through long-term sociocultural and environmental engagement (Raymond-Yakoubian et al., 2017).

It is deeply rooted in history, time, and place, while also being rich, adaptable, and dynamic, all of which keep it relevant and useful in contemporary life. This knowledge is part of, and used in, everyday life, and is inextricably intertwined with peoples' identity, cosmology, values, and way of life. Tradition—and TK—does not preclude change, nor does it equal only “the past”; in fact, it inherently entails change (Raymond-Yakoubian et al., 2017).

In the North Pacific, there is a significant opportunity to include TK. TK is foundational to an equitable, climate-ready fishery platform in Alaska. As the climate changes, the need for this type of knowledge and way of knowing is even more pronounced. For instance, Alutiiq fishermen we spoke with as part of this study said it is the “rate of change” systems are experiencing that is unprecedented and alarming. Cod is understood to come and go; however, the marine system as a whole is being challenged. These valuable long-term insights enable scientists and managers to think about and address marine resource issues with a unique and layered perspective that considers humans and the ecosystem as a whole over time frames and scales that can exceed conventional data sets.

LK is defined by the NPFMC Local Knowledge, Traditional Knowledge, and Subsistence (LKTKS) Task Force as including the observations and experiences of local people in a region as well as people with significant experience or expertise related to a particular location, species, or fishery.

LK can evolve over time, and it is often acquired over the course of a few generations or less, but it is inherently the product of knowledge formation and dissemination based on personal, shared and inherited experience. It is recognized that bearers of LK are often relatively small groups of people, living in or connected to, a common geographic location who actively engage with the environment through local harvest of wild resources. However, these people may or may not be Indigenous to the area or base their understandings on knowledge that evolves over many generations (St. Martin et al., 2007; Murray et al., 2008; LKTKS Taskforce, 2020).

Fishermen harvesting GOA Pacific cod can provide valuable insights into cod spawning times, distribution and body condition as well as provide real-time ecosystem information from the fishing grounds (Peterson and Carothers, 2013; Stephenson et al., 2016). Fishermen’s experience and LK can also support adaptive management strategies with a unique perspective of developing spatial and/or harvest modifications. For instance, fishermen interviewed as part of this study indicated that more emphasis on harvest limits in specific bays near Kodiak may help prevent localized depletions in state waters. However, the pathways for communicating this information to federal or state managers were either not available or not sought out.

LK is often included in the NPFMC process through testimony and letters presented at meetings. Historically, however, TK has largely been disregarded, and there still is no systematic process for incorporating TK into fishery management. TK and LK surveys and studies are one way to increase representation of Indigenous peoples’ and fishermen’s observations and experiences. Cooperative research and workshops would also foster collaboration and communication between fishing and/or coastal communities and fishery managers. The NPFMC is currently working to better include different types of data through implementation of the Bering Sea Fishery Ecosystem Plan (BS FEP). In particular, the NPFMC is developing an LKTKS Action Module under the BS FEP to identify protocols for incorporation of multiple ways of knowing into fishery management. This work can and should be advanced and extended to the GOA. Opportunities to bolster inclusion of multiple ways of knowing at all regional Councils include increased tribal consultation for relevant issues, tribal representation on Council bodies and Plan Teams, and explicit consideration of TK/LK for applicable management actions.

Management change

Monitoring, indicator development and evaluation, and incorporating different ways of knowing are foundational components needed to advance climate-ready fishery management in the GOA and globally. To effectuate change on the water, however, the information gathered in the processes described above must translate to knowledge-based and precautionary management actions.

The list below highlights promising new areas and recommendations to build capacity in climate readiness in GOA fishery management:

• GOA FEP—Managers must learn from the GOA marine heatwave and the closure of the federal Pacific cod fishery and begin to implement the management tools needed to support fisheries and fishing communities in a volatile climate. One clear step is to advance the use and implementation of FEPs, which have been a primary tool to operationalize EBFM in US fisheries (Levin et al., 2018; Marshall et al., 2018). In 2018, the NPFMC adopted the BS FEP to serve as a tool for the “continued incorporation of ecosystem goals and action into management” (NPFMC, 2020a). Two Action Modules are being developed under the framework of the BS FEP: (i) Climate Change, and (ii) LKTKS. These modules are intended to provide information and recommendations to address fishery and key species vulnerability to climate change to enhance the resilience in fishery management and to develop protocols for improved incorporation of LK and TK in management (NPFMC, 2020). Managers should develop an FEP for the GOA and think proactively about ways that management can adapt to utilize the information and recommendations developed through an FEP process.

• Knowledge-based decision-making and co-production of knowledge—Fishery management will be improved by utilizing multiple types of knowledge. Including TK in fishery management decisions is supported by the Magnuson-Stevens Act, and TK will contribute to NPFMC processes by “minimizing impacts of management to subsistence communities, creating open and transparent processes, and improving ecosystem-based fisheries management frameworks” as well as many other benefits (Raymond-Yakoubian et al., 2017). TK should be on equal footing with Western science, and co-production of knowledge approaches can assist in considering fisheries and communities within larger ecosystem contexts (Raymond-Yakoubian et al., 2017). Tribal representatives, TK holders, and scientific TK experts must have equitable voices throughout the NPFMC process and must be at the centre of developing methods and processes for including TK throughout fishery management processes.

• Tools to address uncertainty—In 2018, the NPFMC’s Scientific and Statistical Committee requested improved transparency in identifying criteria for reducing ABC from the maximum permissible ABC (Dorn and Zador, 2020). In response, an NMFS working group developed a risk classification matrix for assessing four primary considerations: assessment, population dynamics, ecosystem, and fishery performance. Such considerations are intended to capture risk or uncertainty not accounted for in the stock assessment itself (Dorn and Zador, 2020). The 2019 Pacific cod stock assessment reported that three out of four (assessment, population dynamics, environmental) risk categories were substantially increased, suggesting the GOA Pacific cod ABCs should have been set below the maximum level if the fishery were to open (Barbeaux et al., 2019). This approach has gained traction in the Council process, and in 2020 all full stock assessments include these “Risk Tables” to inform ABC determinations. As this process continues to be standardized and developed, the “Risk Tables” can provide a meaningful risk assessment tool that can support precautionary management actions and should be extended to stock assessments and harvest specifications in other regions.

• Climate and indicator informed stock assessments—Ecosystem and Socioeconomic Profiles (ESPs) have recently been developed for a number of groundfish and crab stocks in Alaska, including sablefish, GOA pollock, Eastern Bering Sea and GOA Pacific cod, Bristol Bay Red King Crab, and St. Matthew Island Blue King Crab. These new profiles are included as an appendix in stock assessment evaluation reports and are intended as a standard framework to assist scientists and managers in incorporating ecosystem and socioeconomic indicators within the stock assessment process (Shotwell et al., 2019). ESPs have the potential to bridge the gap between ecosystem and socioeconomic research, stock assessment, and eventual management outcomes. ESPs should continue to be developed for all stocks for which there are sufficient data. Where stock-specific data are insufficient to support an ESP, this process will highlight information needs.

• GOA Management Strategy Evaluations (MSEs)—MSEs and Vulnerability Assessments are additional tools that can provide strategic climate guidance to decision-makers in Alaska and in other regions. MSEs utilize a simulation-based approach to explore various management options and identify trade-offs within management objectives (Fulton et al., 2014). Vulnerability Assessments can address risks and vulnerability at numerous scales depending on the project objective, ranging from ecological risk assessment to coastal community vulnerability assessments. The Alaska Climate Change Integrated Modeling project (ACLIM) has been used to predict and evaluate physical, biological, and fishery responses to projected climate scenarios in the Bering Sea (Holsman et al., 2020). Developing similar MSEs and Vulnerability Assessments in the GOA will aid in identifying clear thresholds and management responses ahead of time such that management is most responsive to the changes happening and the populations or species most vulnerable (Busch et al., 2016; Colburn et al., 2016).

• Translating marine forecasts to management—Hobday and Pecl (2014) identified the GOA as one of roughly 50 areas that are climate change “hotspots” based on rapid ocean warming conditions in the last 50 years and model predictions indicating warming conditions will persist. This study notes that regions with heavy human dependence or reliance on commercial fisheries may be most vulnerable to climate change but will also provide important opportunities for lessons learned and marine ecological forecasting (Hobday and Pecl, 2014; Pethybridge et al., 2020). Marine forecasting technology has expanded significantly in the last decade. Emerging model forecasts are generally based on marine climate and physics. Therefore, an intermediate “translation step” is required to convert physical forecasts to biologically relevant (and eventually) management-relevant information (Payne et al., 2017). In the GOA and elsewhere, this “translation step” will require a sound mechanistic understanding of species responses to environmental change and will inherently build upon the indicator evaluation work described above in Indicator evaluation section. Stakeholder engagement, from inception to results, of marine ecological forecasts will enhance the uptake and utility of the information in fishery and management decision-making (Payne et al., 2017).

• GOA ecosystem production and function—Unlike the Bering Sea Aleutian Islands, the annual optimum yield (OY) cap on groundfish removals in the GOA has not been constraining since its adoption in 1987 (NPFMC, 2020b). This gap leaves room for the implementation of a more progressive form of climate-informed, region-wide ecosystem-based harvest limit (in addition to species-specific TACs) that considers broader ecosystem production and function across all trophic levels (Tam et al., 2017; Vallina et al., 2017; Holsman et al., 2020). Guild level-biomass estimates, trophic dynamics indices, and/or fish community mean lengths are examples of indicators relevant to structural and functional ecosystem attributes as they respond to climate change (Tam et al., 2017). In late fall 2020, the NMFS initiated a large-scale integrated modelling project to evaluate the drivers of system-level productivity under climate change and to identify potential fisheries management responses in the GOA (M. Dorn, pers. comm.). As GOA ecosystem indicators are better developed, they should be used to inform a revised GOA FMP OY cap that directly considers regional productivity and function.

• GOA habitat protections—Protecting Alaska’s benthic and coastal habitats will help buffer communities and the marine species depended upon from the impacts of climate change (Etnoyer and Morgan, 2006; Ruckelshaus et al., 2013). While a large portion of the eastern GOA is closed to bottom trawling, additional benthic habitat, and coastal protection measures will only benefit user groups and marine ecosystems in the long term.

Conclusions

Sea surface temperatures are projected to increase substantially in the next 100 years (IPCC, 2019). From 1925 to 2016, marine heatwave days increased by 54% globally, and this trend is predicted to continue (Oliver et al., 2018). Fishery participants and managers must think critically about how to develop climate-ready fisheries in the short and long term in the context of increasing scientific uncertainty (Kritzer et al., 2019). As marine heatwaves become more frequent and severe, our current understanding of species relationships and interactions must change and adapt (Barbeaux et al., 2020; Holsman et al., 2020). Additional research is needed to identify how climate-ready fishery management can better account for socioeconomic considerations and equity to ensure that management changes reduce community vulnerability as opposed to exacerbate it.

The decline of Pacific cod in the GOA resulting from an extended marine heatwave laid bare the challenges ahead. Even in a relatively well-managed and data-rich fishery context, there were particular challenges associated with detecting change and initiating management response on a time scale that would have minimized impacts to the stock and fishery participants. Continued and/or expanded surveys, and ways to more thoroughly respond to information from LK and TK sources, would aid in detecting change earlier. Continued research on links between environmental drivers and stock performance, like that of the relationship between temperature and Pacific cod hatch success, are increasingly valuable. Similarly, a better understanding of ecological relationships and how prey availability for target stocks may change in the context of events like marine heatwaves is needed. Continued development of indicators that can be tied to management through mechanistic understanding and operationalized through the use of reference points and triggers, could aid in initiating timely management adaptations. Failure to heed the lessons of the GOA Pacific cod experience will mean repeated fisheries disasters causing long-term losses, whereas successful development of climate-ready fishery management will help reduce the likelihood, severity, and consequences of future disruptions from environmental change.

Data availability

The interview data underlying this article cannot be shared publicly in order to ensure the privacy of the individuals who participated in the study.

Acknowledgements

We thank Steve Barbeaux and Henry Huntington for their advice and constructive comments on this essay as well as the anonymous reviewers for their helpful recommendations. Thanks for Patricia Chambers for her technical asstistance. We also thank the respondents for their thoughtful answers during interviews.

Peterson Williams, M. J., Gisclair B. R., Cerny-Chipman, E., LeVine, M., and Peterson, T. 2021. The heat is on: Gulf of Alaska Pacific cod and climate-ready fisheries. – ICES Journal of Marine Science, 00: 000–000.

Contribution to the Themed section: ‘Exploring adaptation capacity of the world’s oceans and marine resources to climate change’