August 17, 2017 — The oceans are getting warmer, and fish are adapting to rising ocean temperatures with their fins and swimming to waters that better suit their temperature preferences. Shifts in the distribution of important coastal fish species are resulting in changes to historical fishing options, new fishing opportunities and new fisheries management challenges.
There are many examples of the distributions of fish species changing in response to the warming oceans, but let’s focus on a few species important to Delaware both past and present. Winter flounder were popular recreational fish decades ago, but they have largely left Delaware waters that are now too warm. Summer flounder and black sea bass remain two of the most sought-after recreational fish in Delaware, but their distribution is gradually shifting northward, with fewer fish available in Delaware waters.
While flounder and black sea bass are examples of changing fish distributions that have decreased fishing opportunities in Delaware, other species seem to be more available in Delaware due to the warming ocean, such as cobia and blueline tilefish, with other southern species likely to become more common in Delaware as our waters continue to warm.
Changing temperatures, changing fish
Winter flounder were a popular, cool weather catch for Delaware’s recreational anglers during the 1960s and 1970s. Delaware was at the southern range of winter flounder distribution and their departure from Delaware waters began soon after those peak years. The number of winter flounder caught during December in Delaware’s Inland Bays by the Division of Fish and Wildlife’s trawl survey declined by more than 90 percent between 1966 and 1981.
Adult winter flounder had virtually disappeared from the trawl survey catches by the early 1990s, with a similar and notable reduction in recreational angler catches. Winter flounder have suffered a steep population decline over the past 20 years and the current winter flounder distribution suggests that this species is still moving north to stay in its preferred temperature range, making it unlikely that they will return to Delaware.
Read the full story from Outdoor Delaware at the Delaware State News