Development and test of a remotely operated Minisampler for discrete trawl sampling

Systems that take discrete samples of the catch while trawling are widely used in fisheries investigations. We have developed the Minisampler, a relatively small system to be used particularly on small vessels and small trawls. The device is simple, has low weight and is reasonably cheap to make. The Minisampler consists of a tele-command deck unit, a dunking transducer, a stainless steel frame and one or two acoustical trigger-units.

Each of them releases a metal bar that opens/closes a collecting bag. Thus is possible to take two or three remotely controlled discrete samples during a tow. We tested the system successfully in a flume tank and during sea trials from a commercial trawler. The Minisampler is a multi-purpose tool and provides opportunity for new experimental designs to improve scientific work using demersal or pelagic trawls in marine or freshwater environments.