Data requests may be made to Scott Olszewski, RIDEM Marine Fisheries Section, at Scott.Olszewski @dem.ri.gov
The RI Department of Environmental Management (RIDEM) monitoring data have shown a marked decline in lobster populations since the 1990s, correlating with trends in lobster harvest levels. While trawl surveys showed an increase in lobsters in 2005-2008, that level was not sustained and there have been further declines since then. URI scientists conducting trawl surveys in Rhode Island waters have observed a similar pattern. Results of the ventless trap surveys show either a decreasing or stable abundance in Southern New England.
Explaining Lobster Trends
Rhode Island’s highest ever lobster catch was in 1999, with a total value of over $31.5 million, and there has been a steady decline in landings since then, which has reverberated throughout the state’s lobster industry. In 2015, Rhode Island issued 833 commercial lobster licenses, down from 1302 licenses in 2003. Also during this period, Rhode Island based the number of traps allowed to each licensee on their historic number of traps fished, which further limited fishing effort and the resulting catch. Following the general rules of supply and demand, decreasing the supply of lobsters should lead to increasing price, which can mitigate the impact to the industry. This upward pricing trajectory is what one would expect to see based on Rhode Island landings alone; however, northern New England is seeing a far different trend than southern New England. Maine landed its largest lobster harvest ever in 2015, over 100 million pounds and more than 2.5 times larger than the Rhode Island catch 15 years ago. This means that the regional lobster supply stays high, and the price stays low, further injuring the southern New England’s lobster industry.
Rhode Island’s struggling lobster population cannot be conclusively tied to a single cause. Lobster shell disease is part of the problem as well as increased predation by recently recovered fish populations. Scientists have also found that warming waters are almost certainly a significant culprit. Researchers at Princeton found that lobsters off the northeast coast have been moving 43 miles north per decade. Other studies in Maine found a 2.8mm (0.11 inch) decrease in lobster length for every one degree Celsius (1.8 degrees Fahrenheit) increase in ocean bottom temperature, and decreased survival rate of lobster larvae in warmer waters. Meanwhile, water temperature in Narragansett Bay has increased over two degrees Celsius (3.6 degrees F) since 1960. These results do not bode well for Rhode Island’s lobster industry, making scientifically sound management practices and monitoring of lobster populations even more important in the coming years.