‘By-catch’- A problem of the industrial shrimp fishery in Ghana
Ghana has an important Industrial Shrimp Fishery which is based at the Tema fishing port. In March, 1996, I joined two of the shrimp trawlers (MV Benhill 10 and MV Benhill 3) to sea on a normal commercial fishing trip. Data was collected from three fishing grounds, off the Ghanaian coast, on the catch, by-catch and discards in addition to observations of fishing practices and behaviour. Except for times of mechanical failure or the need for repairs, trawling tended to be for long periods and were continuous throughout day and night. The trawlers fished in shallow waters (depths of between 18 and 37 m) and close to shore (between 2.8 and 4.0 nautical miles). The fish and invertebrate catches were diverse both at night and during the day. Catches also included substantial quantities of litter and occasional catches of sea snakes, sharks and a sea turtle. There was an enormous but variable amount (both in weight and numbers) of by-catch in hauls. A large portion of the by-catch was discarded with most of them already dead. The discards consisted mostly of small individuals which were either juveniles of commercial species or species which were of no commercial value. The practice of catching and discarding portions of the catch back into the sea, with little chance of survival, is viewed as posing a great ecological problem for the marine environment off the Ghanaian coast.