Projected Impacts of Climate Change – Potential Winners and Losers
Projections for Atlantic cod under a high greenhouse gas emissions scenario to the year 2100 suggest that cod in the U.S. NES LME will be vulnerable to a loss of thermal habitat from Georges Bank to the southern limits of its present-day range (Figure 23).
In the Gulf of Maine, the early life history survival of cod is projected to decline with increasing ocean temperature, rendering the stock more vulnerable to high fishery mortality rates. Projected yields of cod in the Gulf of Maine under various temperature conditions and various levels of fishing mortality show a robust, negative influence of warming temperature on yield (Figure 24).
A study using a mechanistic individual-based model (IBM) for larval cod in Georges Bank projected the impacts of climate change on larvae survival, weight, and fraction of occurrence in the years 2000-2049 and 2050-2099 (Kristiansen et al., 2014). The projected decrease in large phytoplankton productivity and increase in ocean temperature by the end of this century are suggested to reduce larval cod survival and weight while increasing their occurrence in the upper water column (upper 15 m) where predation rates can be higher (Figure 25).
A coupled climate-population model for Atlantic croaker was developed based on the hypothesis that croaker recruitment is a function of overwintering temperatures in the estuary habitats of juveniles.
Using 14 global climate models, the climate-population model projects that the spawning biomass of Atlantic croaker in the U.S. NES LME will increase by 60% to 100% by the year 2100 if present-day levels of fishing mortality are maintained.
Concomitantly, the center of population biomass is projected to shift 50 to 100 km northward, all together increasing maximum sustainable yield by 30% to 100% (Figure 26).