RV Platessa the central basin. The RV "Platessa" (LT205) was in service with Ministry of Agriculture, Fisheries and Food (United Kingdom) from April 1946 until June 1967, during which time she participated in more than 473 separate research campaigns. She was primarily confined to the southern North Sea, but with occasional forays into the Irish Sea and English Channel, especially in the 1960s. The RV "Platessa" (LT205) was overwhelmingly dedicated to research on North Sea herring and North Sea Plaice. This work included the tagging of more than 12,000 plaice during the 1950s, 7000 during the 1960s. In addition, large numbers of
Demersal fish benthic fish are denser, with negative buoyancy so they can lie on the bottom without any effort. Most demersal fish are benthopelagic. As with other bottom feeders, a mechanism to deal with substrate is often necessary. With demersal fish the sand is usually pumped out of the mouth through the gill slit. Most demersal fish exhibit a flat ventral region so as to more easily rest their body on the substrate. The exception may be the flatfish, which are laterally depressed but lie on their sides. Also, many exhibit what is termed an "inferior" mouth, which means that the mouth