Grid-net design that successfully reduces discarded catch and damage to benthic species in the veined rapa whelk beam trawl fishery

Eryaşar A. R.

MARINE BIOLOGY RESEARCH, vol.19, no.1, pp.1-12, 2022 (SCI-Expanded)

  • Publication Type: Article / Article
  • Volume: 19 Issue: 1
  • Publication Date: 2022
  • Doi Number: 10.1080/17451000.2022.2123523
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aquatic Science & Fisheries Abstracts (ASFA), BIOSIS, CAB Abstracts, Environment Index, Geobase, Veterinary Science Database
  • Page Numbers: pp.1-12
  • Recep Tayyip Erdoğan University Affiliated: Yes


In this study, a grid-net design (GND) with three different bar spacings was compared with the

commercial beam trawl used in the veined rapa whelk fishery to minimize the discarded catch

amount and the loss of commercial product. In addition, the damage and mortality rates of the

species that entered the tested fishing gear were determined to understand whether the

tested fishing gear has a possible negative effect on benthic species. In the grid-net design,

a rectangular metallic grid positioned 6 cm off the ground substituted half of the codend to

allow the escape of discard species. Sea trials were carried out in the south-eastern Black

Sea between 13 and 24 October 2021. Results showed that the discarded catch amount was

significantly reduced by each GND (P < 0.05). Compared with the commercial fishing gear,

the reductions in the discarded catch amounts (in terms of number) were 91.6%, 92.2%, and

95.0% for 22, 25, and 28 mm GNDs, respectively. The minimum commercial product loss was

determined at 22 mm GND. In addition, it was seen that each GND compared to commercial

gear caused statistically significantly less damage and mortality on the discarded species. In

conclusion, 22 mm GND was the most successful design among the tested gears in

minimizing commercial product loss and reducing the discarded catch amount.

Recommendations are given for this design to be adopted by the commercial fleet.