The impact of trammel nets as an MPA soft bottom monitoring method

With the global increase of marine protected area (MPA) implementation, need for monitoring and evaluation their effectiveness becomes ever more important. Currently there is a severe lack information about protection effects soft-substrate ecosystems. While many different methods have been established hard-substrate ecosystems, most these minimally invasive prove ineffective soft- bottom habitats. Information quantification impact needed to provide decision makers with necessary knowledge choose appropriate feasible methods. In this study we quantify experimental trammel net fishing as method demersal fish community using Arrábida MPA (Portugal) case study. Over 14 biannual sampling campaigns (between 2010 2019) 21,873 individuals 5.61 tonnes were caught. The gear highly effective an average catch per unit effort higher than reported commercial fisheries in adjacent areas. When excluding pelagic species, mortality rates are 41.2% 30.4% numbers biomass, respectively. Most dead belong small, non-protected species relatively little value while conservation target groups such Soleidae Rajidae high survival rates. Due its low size- species-selectivity rate valuable proved be communities. Given on local ecosystem nets good alternative areas where non-extractive not effective. Nevertheless, other enable determination lowest future monitoring.