Climate change will have wide-ranging effects on different aspects of fisheries management, which will cause challenges and shifts in:

• Abundance & Productivity
• Changes in Distribution & Recruitment
• Conversion or Loss of Essential Habitat

To better understand the needs of marine fisheries managers and other professionals to respond to a changing climate, we released an online survey and collected responses between August 2014 and February 2015:

• Needs Assessment Survey

Abundance & Productivity

Warmer temperatures may lead to reduced health and abundance (Chapin et al. 2014) making current levels of fishing and harvest pressure unsustainable over time. Fisheries managers will need to consider ways to adapt to potential stock declines, such as adjusting quotas and fishing season timing (e.g., earlier or later start), or redefining stock areas (Link et al. 2010; Chapin et al. 2014). Managers may also consider multi-species licensing and permitting systems that allow fishermen to have more flexibility in their target stocks and adjust to shifting species distributions (McIlgorm et al. 2010; Johnson 2012). In the Pacific Islands, current levels of fishing pressure for skipjack (Katsuwonus pelamis) and yellowfin tuna, for instance, are unlikely to be sustainable under future conditions (Guidry and Mackenzie 2011). Managers may need to alter management plans, adjust catch quotas, or end harvest entirely.

Ocean acidification will also impact some fisheries’ productivity levels. In order to help minimize the effects of ocean acidification, managers may be able to take actions such as targeted placement of vegetation and shells (e.g., used oyster shells) that may help absorb CO2 and provide a buffer against corrosive waters (WA Blue Ribbon Panel on Ocean Acidification 2012). Additionally, some hatchery operators will need to monitor and adjust water intake at shellfish production facilities, or even move production facilities to other regions (Barton et al. 2012; Feely et al. 2012). Actions taken on a local scale that minimize coastal erosion and land-based runoff may help alleviate acidification effects by minimizing other sources of stress that exacerbate acidification (e.g., more intense and frequent storms, pollutant runoff, bleaching) (Kelly et al. 2011).

Distribution & Recruitment

Altered distribution of fish populations and changes in recruitment due to climate change will require fisheries managers to employ multiple strategies. To account for potential shifts in species’ ranges, managers may need to consider implementing flexible permitting strategies that allow fishermen to switch between species or target new species (Mills et al. 2013). Managers will need to assess how stocks respond to changing conditions, document range shifts, and potentially alter catch quotas to account for declines or increases in stocks (Schindler et al. 2008; McIlgorm et al. 2010; Sydeman and Thompson 2014). More strictly managing anthropogenic stressors, such as pollution and overfishing, may help protect fish habitat and populations. There will also be a need for managers to assess shifting stocks to determine new boundaries, stock size, and any potential merging that may occur between sub-species that were formerly distinct stocks (e.g., silver hake) (Link et al. 2010). For some species, such as North Atlantic cod, managers may need to consider reducing catch quotas to reduce fishing pressure on already vulnerable stocks in order to increase their resilience to climate impacts (Fogarty et al. 2008). It is possible that new stock assessment protocols may be needed to respond to the changing location and phenology of fish populations (Hansen and Hoffman 2011).

Habitat Conversion or Loss

Climate change will also impact essential fish habitat, including nursery grounds and spawning areas. Managers will have to monitor, manage, protect, restore, and identify new suitable locations of fish habitat. In tropical systems, managers will need to consider how to mitigate the loss of important coral reef and mangrove habitat, including restoring degraded habitats. In addition, actions to reduce non-climate stressors, such as land-based pollution and destructive fishing practices, may help make corals and mangroves less vulnerable to climate stressors (Guidry and Mackenzie 2011; Keener et al. 2012). Technological tools, such as early warning systems to monitor water temperature in order to help predict potential bleaching events and identify more resilient reef areas, may inform or identify useful adaptation strategies (Keener et al. 2012). On the West Coast, remediating actions, such as the removal of physical fish barriers or restoration of freshwater habitat, may help curb habitat loss and protect sensitive salmon populations (CA Fish Passage Forum 2014).

Table 8 presents key challenges to fisheries management posed by climate change categorized by effects on abundance and productivity, distribution and recruitment, and essential habitat, along with potential management approaches to address each challenge.