RV Huxley contribution to the International Council for the Exploration of the Sea (Scotland, the northern section, was treated differently). Fishery investigations began in September 1902 under the directorship of Walter Garstang. The work consisted of systematic exploration of the North Sea trawling grounds at different seasons of the year, together with studies of growth and migration of plaice "Pleuronectes platessa" based on tagging experiments, examination of the food of fish and the nature of the seabed. Detailed catch records from North Sea survey stations between 1902 and 1903 were summarised in a report published by Garstang in 1905. Research continued until
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