Implications of Future Northwest Atlantic Bottom Temperatures on the American Lobster (Homarus americanus) Fishery

Abstract

Sea surface temperatures of the northwest Atlantic have warmed dramatically over the last several decades, while benthic temperatures have increased at a slower pace. Here we analyze a subset of the CMIP5 global Earth system model ensemble using a statistical downscaling approach to determine potential future changes in benthic temperatures on the northwest Atlantic continental shelf and slope (<500 m). We put future changes in the context of possible impacts of ocean warming on the high‐value, wild‐caught American Lobster (Homarus americanus) fishery. Future bottom temperatures of the northwest Atlantic under a business‐as‐usual (RCP8.5) and a climate‐policy (RCP4.5) scenario are projected to increase by 0–1.5°C and 1.2–2.4°C by 2050 and 0–1.9°C and 2.3–4.3°C by the end of the century for RCP4.5 and RCP8.5, respectively. H. americanus experiences thermal stress at temperatures above 20°C, and projected increases in temperature is likely to result in changes in the distribution of optimal thermal egg hatching and settlement indicators. Inshore regions of southern New England, where H. americanus biomass and catch have been declining historically, will likely become inhospitable under either future scenario, while thermal egg hatching and settlement indicators will expand offshore and in the Gulf of Maine. These changes imply that members of the fishery based in southern New England may need to recapitalize to larger vessels to prepare for potential changes brought on by future climate warming. Results from the downscaling presented here can be useful in preparing for potential changes to other fisheries or in future climate vulnerability analyses.

The cresting wave: larval settlement and ocean temperatures predict change in the American lobster harvest

“…Furthermore, downscaled projections of sea temperature in coastal areas are increasingly available, enabling finer scale projections (Rheuban et al. ). The challenge will be to find the set environmental factors representing key drivers of population change into the future.…”

“…Similar data are available for a number of fisheries and their environments globally (see FishBase; https://www.fishba se.in/home.htm). 5 Furthermore, downscaled projections of sea temperature in coastal areas are increasingly available, enabling finer scale projections (Rheuban et al 2017). The challenge will be to find the set environmental factors representing key drivers of population change into the future.…”

Trends in Physical Properties at the Southern New England Shelf Break

“…This has impacted the continental shelf ecosystem (Record et al, ; Walsh et al, ) with important economic consequences for the commercial fishing industry. Future projections of bottom temperature for this region indicate significant effects for the lobster industry in particular (Rheuban et al, ).…”

Observational Needs Supporting Marine Ecosystems Modeling and Forecasting: From the Global Ocean to Regional and Coastal Systems

“…For example, Hales et al (2012) were better able to constrain a semi-mechanistic model of the carbonate system in the California current, with reduced error and reliance on non-mechanistic predictor variables. Kavanaugh et al (2017) and Rheuban et al (2017) were able to better predict benthic temperature trends and drivers along the NE continental shelf by first applying a seascape classification that characterized the seasonal shape of water column temperature gradients. Plankton and bacterioplankton community structure are different across dynamic seascapes (Gomez-Pereira et al, 2010;Kavanaugh et al, 2015), with ongoing efforts to validate seascape patterns at higher trophic levels, including endangered species, such as Atlantic Sturgeon (Breece et al, 2016).…”