Ocean Ecosystem and Resources : Status, Trends, and Linkages
Shifts in Species Distributions Associated with Climate Change
Climate change will affect the distribution of all marine species from the base of the food web to apex predators. In general, marine species in the Mid-Atlantic are expected to shift northward, eastward, and/or into deeper water in response to climate change (NEFSC 2015). For all marine species, changes in temperature and seasons could also affect when and where reproduction and migration take place (Link et al. 2015). However, it is a challenge to predict the response of every species, as well as the entire ecosystem, due to differences in each species’ life history, preferred habitat, prey, and external pressures from humans such as harvesting and habitat destruction. The best understanding of species shifts from climate change comes from long-term monitoring programs. While shifts in species distributions are changing the ecology of the region, they are also complicating fishery management by changing the nature of traditional fisheries and opening opportunities to fish for new species in the area.
Shifts in distribution of a substantial number of fish and invertebrate species in the Mid-Atlantic region have been documented based on long-term datasets from research vessel surveys conducted by state and federal resource agencies. Within the region, a significant number of species have moved poleward and/or to deeper water (Nye et al. 2009, Lucey and Nye 2010). These changes have been connected to increasing water temperatures but in some cases (e.g., summer flounder) have also been linked to changes in the age and size composition of the stock and reflect shifts in distribution related to different species movement patterns (Link et al. 2015).
Climate is also changing the distribution of fish larvae, as well as the timing and location of spawning (Walsh et al. 2015). Butterfish and Atlantic mackerel are two species that have shifted in an opposite direction in the Mid-Atlantic Bight – towards shore rather than northward (Walsh et al. 2015). As bottom water temperatures have increased, there is clear evidence that surf clams (an important fishery in the Mid-Atlantic) have shifted into deeper waters at the southern extent of their range (Weinberg et al. 2005). The NOAA Northeast Fisheries Science Center has developed map products that display these findings, including the movement of species along the shelf and across the shelf through time, changes to the location of population cores through time, and animations of changes in abundance through time.
The impacts of other human stressors (historical and present) can complicate the measurement and monitoring of shifts in species distributions because they can confound any clear trends. Studies at the global scale predict that marine biodiversity could be redistributed to different areas within the worlds’ oceans, rather than lost (Molinos et al. 2015).
Selected Sources of Further Information
OceanAdapt: Interactive graphs of species shifts (Rutgers University and NOAA)
Where’s my fish? New tools to visualize climate and other impacts on marine animals (webinar) (Malin Pinsky, Rutgers University)
Warming oceans drive east coast fish to cooler waters (Scientific American)