November 5, 2018 — NOAA researchers studying the 85 percent decline between 1980 and 2010 of the four most commercially-important bivalve mollusks — eastern oysters, northern quahogs, softshell clams, and northern bay scallops — have identified the causes.
Along with the sharp decline in commercially important bivalves, there has been a corresponding decline in the numbers of fishermen (89 percent) who harvested the bivalves, said researchers with NOAA’s National Marine Fisheries Service.
The bivalve declines are in contrast to the previous three decades (1950–80) when the combined landings of the same bivalves were much higher and the trend in each of their annual landings was nearly level, decade by decade.
The only exceptions to the declines were seen in the harvest of northern quahogs in Connecticut and American lobsters in Maine. However, the numbers of American lobster landings have fallen precipitously – as much as 98 percent – from southern Massachusetts to New Jersey.
The researchers also found during the course of the study that a number of groups of marine and land animals have also experienced large shifts in abundance since the early 1980’s.