6. Social and Environmental Vulnerability

6.1 Climate Vulnerability

The California Current Ecosystem is vulnerable to numerous impacts associated with ocean and climate change including:

• Ocean warming is affecting environmental patterns such as wind and upwelling.
• Scientists have linked the 2014-2015 warm water ‘Blob” in the Eastern Pacific Ocean to the West Coast’s longest and most widespread HAB event in history. Harmful algal blooms (HABs) are becoming more frequent and severe, with some producing domoic acid, a potent neurotoxin that accumulates in the viscera (and in some cases the meat) of shellfish (bivalves, crustaceans) and some finfish and, when ingested, poses human health risks. When HABs die off and decay, they reduce the amount of oxygen in the water, potentially creating “dead zones” which can affect species distributions. During 2015-16, a large and persistent HAB on the West Coast led to unprecedented DA-related season delays and closures for California’s Dungeness and rock crab fisheries, respectively (Source).
• Sea level rise/flooding threatens coastal communities, including port infrastructure, and can exacerbate the impacts of king tides.
• Shifting wind patterns and intensification that result from changes to ocean temperatures and upwelling patterns pose safety risks to fishers.
• Ocean acidification and changing ocean chemistry impact shellfish and associated fisheries.
• Shifts in abundance and distribution can drive highly localized impacts on fishing communities depending on social and economic resilience and management constraints (Source).

Fishing communities’ experiences with ocean and climate change vary greatly depending on environmental, social and economic factors (Source). The impacts of climate change play out shoreside through social and economic networks at the port, in the fishery support and seafood supply system, and throughout the larger community.

Despite these challenges, climate change could create new opportunities for fishers, for example when species shift north into the range vessels operating out of a given port. However, opportunities such as access to new fisheries can be limited by existing management (e.g., restricted access), cost of entry (e.g., for vessels, gear, permits, fishing knowledge/expertise) (Source). Below is a brief description of some of the potential implications for Half Moon Bay’s primary fisheries.

Dungeness Crab

• Ocean warming poses a great risk to the Dungeness crab fishery (Source). Sustained warmer ocean temperatures create ideal conditions for HABs and elevated domoic acid (DA) levels, potentially prompting delays and closures in the commercial and recreational fisheries
• Ocean acidification (OA) poses a threat to the crab fishery, as it is known to cause shell dissolution (Source), decreases in shell width, and increased mortality in crabs (Source).

Coastal Pelagic Species

• Within the coastal pelagic species (CPS) management group, there is wide variability in both species exposure and vulnerability to climate change. In general, the forage fish that constitute CPS are more exposed and sensitive to climate change impacts in the northern and central nearshore regions of the California Current ecosystem, making them more at risk for climate impacts (Source).
• CPS and/or market squid range may temporarily extend further north than previously observed, creating the potential for an expanded fishery (Source).

Market Squid

• Market squid is highly sensitive to changes in ocean conditions, which can cause extreme variability in species abundance and availability to the fishery (based on depth and latitude). Because market squid has a short life span (6-9 months), extended warm water periods could impact species abundance and availability, resulting in extended periods of low catches under shifting ocean conditions.
• Climate change may also result in shifts in suitable habitats for market squid. During the broader scale warm-water “Blob” event of 2014-2015, the species shifted northward and continues to be found in fishable aggregations in northern California and well into Oregon.
• Changes in oxygen levels could impact both embryo and adult habitats (Source).

Salmon

• Salmon are at risk of multiple impacts from climate change. Extreme drought conditions, high flows, and hotter water temperatures impact salmon habitat. Habitat restoration competes with agricultural and other forms of water use. Ocean acidification affects salmon spawning behavior negatively, resulting in lower returns. Warming surface temperatures negatively impact smelt survival. Salmon resilience is limited by the unprecedented rate of change and habitat loss (Source).

Groundfish

• Lower oxygen levels resulting from higher ocean temperatures may impact species distributions along the West Coast (Source).
• Biomass of some species (e.g., sablefish [black cod] is expected to decline under increased ocean temperatures) (Source).
• Deeper water species may be somewhat sheltered from changing conditions with the potential to expand distribution to encompass deeper habitats (Source).

6.2 Community Social Vulnerability Index

NOAA developed a suite of social indicators, the Community Social Vulnerability Index (CSVI), for use in fisheries social impact assessment. These indices address social well-being and sustainability and include measures of vulnerability and resilience for coastal fishing communities. It is important to note that much of the data used to determine CSVI rankings is for US Census Bureau “Census-Designated Places” rather than fisheries per se and therefore reflect the demographics of the wider community, rather than fisheries participants specifically.

Based on 2016 data, Half Moon Bay ranks low vulnerability on the CSVI in terms of most social indices (e.g. labor force, poverty, housing characteristics and personal disruption) however it ranks medium-high as a function of population composition. Half Moon Bay ranks highly vulnerable to urban sprawl. In 2019, the poverty rate was 5.4%, compared to 10.5% nationally. The city had a 63.6% employment rate, compared to 61% nationally. The impacts of climate change are amplified when a community is already socially and economically vulnerable because their ability to adapt to the impacts of climate change on primary fisheries is severely limited.

For more information and a detailed definition of each indicator, go to NOAA Fisheries.