Triple-D dredge benthos sampling

Triple-D dredge The Triple-D (Deep Digging Dredge) was developed to quantitatively sample the larger-sized, often more sparsely distributed and longer-lived in- and epifauna. A prototype was described in Bergman and van Santbrink (1994). The Triple-D (2.40* 2.60*1.20 m; weight 1200 kg; towing speed 3 knots) effectively excises a 20 cm deep strip of sediment with a width of 20 cm from the seabed, of which the length of 100 m is controlled by an odometer triggering a pneumatic opening/closing mechanism. The sediment washes through the 7x7 mm meshes of a 6 m net astern the dredge. Catches of the Triple-D representing the fauna in 20 m2 are sorted and identified on board (for technical details Triple-D see https://www.youtube.com/watch?v=O3XIFzbljWk).