Lobster and Fishes of Long Island Sound
Lobster, which thrive in cold water, have become less common. Lobster landings in Connecticut have declined dramatically from a high of over 3.7 million pounds in 1998 to just over 110,000 pounds in 2018 (most recent data) – almost a 97 percent drop. The decline in lobsters was also confirmed by DEEP’s spring and fall trawl surveys. Researchers investigated several possible causes for the dramatic downturn in lobster populations since 1998 including disease, changes in water quality, changes in climatic conditions and other human impacts to the Sound such as the presence of insecticides. Scientists did not detect pesticides in lobsters collected in 2014, leaving the warming waters as the most likely cause for Connecticut's lobster decline.
As noted above, DEEP surveys marine fish, squid and lobster populations every spring and fall by towing nets from a research vessel. The chart shows the average number of fish species caught in each tow during the spring and fall surveys combined. The well-documented trend toward species that favor warm water is apparent.
A study of 686 species, published in 2018, projects the shifts in thermal habitat for fish species all along the North American continental shelf. The impacts of warmer water temperatures have had mixed effects on finfish found in Connecticut waters. As discussed above, the trend indicates that the mean number of warm adapted species increased significantly while the average number of cold-adapted species declined since 1984. Overall, finfish diversity in Long Island Sound remains high, indicating that the Sound is healthy and that a strong balance of species is able to exploit the full mix of resources available throughout this ecosystem.
Technical Note: * Data from 2010 are missing because no fall survey was conducted that year. Finfish species captured in the CT DEEP Long Island Sound Trawl Survey were divided into adaptation groups based on their temperature tolerance and seasonal spawning habits. New data for finfish species for 2019 added June 1, 2020.