The Southeast and Caribbean region hosts a diversity of marine ecosystems, from tropical coral reefs and subtropical bays to brackish marshes and tidelands, throughout its eight coastal states (North Carolina, South Carolina, Georgia, Florida, Alabama, Mississippi, Louisiana, and Texas), the Commonwealth of Puerto Rico, and the U.S. Virgin Islands. Climate impacts on fisheries in the region will vary from loss of nursery habitat due to sea level rise to increases in the extent of hypoxic areas.

Some of the largest effects on marine fisheries will occur due to increasing air and sea temperatures, more frequent and intense storms, and sea level rise, and resulting effects on species and habitat. Temperature changes are projected to increase the risk of coral bleaching events, incidence of disease (e.g., ciguatera fish poisoning), northward range shifts, potential invasions of tropical fish in subtropical waters, and competition between tropical and native species. Increasing storm intensity and frequency will likely degrade critical habitat (e.g., estuaries, coral reefs) and fisheries infrastructure, as well as impact fishermen safety. Nearshore and estuarine salinity may increase during periods of drought, reducing the amount of suitable fish habitat. Sea level rise will also be a major factor for the region, particularly given the flat topography of the Gulf Coast, and may lead to loss of tidal flats, wetlands, and estuaries used by finfish and crustaceans.

Impacts on Commercial Fisheries

Commercially important fisheries in the Southeast and U.S. Caribbean include South Atlantic menhaden (Brevoortia tyrannus), dolphinfish (Coryphaena hippurus), yellowfin tuna (Thunnus albacares), shrimp, and reef fish and shellfish. In general, changes in temperature, storms, sea level rise, and changes in ocean chemistry (i.e. pH and salinity) will affect species and degrade essential fish habitat. Increasing sea temperatures will likely cause northward shifts of commonly fished pelagic species in the Caribbean, such as dolphinfish and yellowfin tuna (PRCCC 2013), and potential invasions of tropical species that may stress and outcompete native fish populations (Twilley et al. 2001; Needham et al. 2012).

Greater regional storm frequency and intensity may damage fisheries infrastructure (Needham et al. 2012), and cause the loss of important coastal, wetland, and mangrove habitats (Twilley et al. 2001; Ning et al. 2003). South Atlantic menhaden are a common prey source for larger finfish and depend on protected wetland and estuarine areas for larvae and juvenile rearing (Carter et al. 2014); with the degradation and/or loss of these critical habitats, menhaden will likely experience reduced productivity, which will have cascading impacts on other fisheries (Anderson et al. 2013).

In the Gulf of Mexico, shrimp are the most commercially valuable species and are likely to experience fluctuations in yield due to a variety of climate stressors (Twilley et al. 2001). Brown (Farfantepenaeus aztecus) and white shrimp (Litopenaeus setiferus) that use estuaries as nursery habitat could experience declines due to sea level rise, higher levels of nutrient runoff, and increasing saline conditions due to periods of drought and warmer temperatures (Ning et al. 2003). Further compounding these issues, ocean acidification and hypoxia are likely to cause declines in shellfish populations throughout the region (Ning et al. 2003; Needham et al. 2012; Anderson et al. 2013).

Reef fish constitute a major portion of Caribbean fisheries; in a survey of active fishermen in Puerto Rico, 77% reported targeting reef fish (Matos-Caraballo and Agar 2008). Coral reef degradation due to the combined effects of coral bleaching and acidification will lead to declines in commercially valuable fish (e.g., parrotfish, snappers, grouper) and shellfish (spiny lobster [Panulirus argus] and conch [Strombus gigas]) that depend on reefs for foraging, spawning, and protection (Mahon 2002; Valdés-Pizzini et al. 2010). Similar threats face reef fish in coral reefs in the Gulf of Mexico and Florida Keys.

Reduction in the three-dimensional complexity of coral reefs from bleaching, increased macgroalgal cover, and increased erosion of reefs driven by storm intensity is likely to lead to altered behavior and decreased abundance and diversity of reef fish (Mahon 2002; Cooley and Doney 2009; Simpson et al. 2011). Increases in sea temperatures and harmful algal blooms may lead to higher rates of coral disease and toxins in reef fish, such as ciguatera fish poisoning, which is caused by a toxic dinoflagellate (Tester et al. 2010); this dinoflagellate is expected to have a wider distribution as the oceans warm and therefore will pose a higher threat to consumers (Tester et al. 2010; Carter et al. 2014).

Impacts on Recreational Fisheries

Recreational fishing is highly valuable to the economy of the Southeast and Caribbean. It is a multibillion-dollar industry in Florida (Anderson et al. 2013), generates $25 million annually in the U.S. Virgin Islands (Valdés-Pizzini et al. 2010), and supports approximately 200,000 recreational fishermen in Puerto Rico (Page et al. 2013). One of the largest impacts on recreational fisheries will be shifts in species ranges (Cheung et al. 2010; Link et al. 2010); recreational anglers and operators will lose access to popular species and may begin targeting new species (Doney et al. 2014).

Shifting species ranges could result in economic losses for recreational fishing operators (Roessig et al. 2004), although these may be offset as opportunities for recreational catch of new tropical and subtropical species emerge. Climate-driven changes in fish abundance, distribution, and diversity could lead to a decrease in opportunities for recreational fishermen, and economic losses to recreational operators, such as charter boat operators.

Impacts on Subsistence & Traditional Fisheries

In the Gulf of Mexico and Caribbean, fishing is culturally important to many communities and local economies (Needham et al. 2012; Valdés-Pizzini et al. 2010). In Louisiana, coastal tribes depend on fishing for sustenance, livelihood, and cultural heritage, and have already experienced drastic declines in fish availability due to disasters such as Hurricane Katrina and the Deepwater Horizon oil spill (NAU 2014). In Puerto Rico, many local fishermen are self-employed, fish close to home, and use fishing as the primary source of income for their families (MatosCaraballo and Agar 2008); many of these fisheries are mainly artisanal with fishermen using traditional gear such as hook-and-line, traps, and net fishing techniques that have been used for centuries (ValleEsquivel et al. 2011).

Although Caribbean fisheries are not strictly subsistence, they operate at a much smaller scale than large commercial fishing operations in other parts of the region, and therefore are likely to be strongly impacted by fish population changes, such as declines in reef fish or northward range shifts of pelagic species. Further deterioration of coastal ecosystems and declines of multiple finfish and shellfish stocks is likely to impact the culture and economies of these local fishing communities.

Impacts on Aquaculture

In the South Atlantic, shellfish aquaculture is an important component of the economy, with notable species groups including clams and oysters (Anderson et al. 2013). Aquaculture operators may experience potential declines in farmed species due to rising sea temperatures, increased disease susceptibility, decreased pH and oxygen levels, and inundation of coastal facilities due to sea level rise (Anderson et al. 2013). In the Gulf of Mexico, aquaculture of small bait, food fish, and shellfish (e.g., shrimp, oysters, crawfish) is a valuable regional industry (Twilley et al. 2001) and likely to experience similar declines.