Response of soft-bottom macrobenthic assemblages to artisanal trawling fisheries in a subtropical estuary

Trophic structure of a nektobenthic community exploited by a multispecific bottom trawling fishery in Northeastern Brazil

“…Particularly concerning the bottom trawling, direct food web effects are associated to the reduction of species richness and abundance [ 17 – 19 ], however, important indirect consequences are usually disregarded [ 20 ]. The capture of non-targeted species by bottom trawling may be a potential risk for the ecosystem sustainability, not only by removing predators of high trophic level, but also prey of lower trophic levels, as the untargeted invertebrates [ 14 , 21 – 23 ]. For example, a decline in prey availability for demersal fishes, could potentially reduce food intake and body condition [ 24 ], causing a trophic cascade effect, changing the ecosystem control equilibrium, either top-down or bottom-up, or even reaching the extreme collapse of the ecosystem [ 25 – 27 ].…”

Spatial and temporal variations of sediments in a subtropical microtidal estuary

“…Declining biological productivity along with strong winter storms facilitates erosion, creating a cycle of erosion and deposition (Dyer et al, 2000). It has been reported that on shallow areas of the Patos Lagoon estuary occurs a decrease of macrofauna during winter periods (Bemvenuti & Netto, 1998;Rosa & Bemvenuti, 2006;Ortega et al, 2018), which can be extended to spring at high precipitation periods with consequent decrease on salinities (Colling et al, 2007, Ortega et al, 2018. The years 2015-2017 were years of high rainfall mainly in the spring, causing decline of the macrofauna (Ortega et al, 2018), which could facilitate together with the strong winds the erosion of the sediment of the shallow sites and their deposition in deeper zones.…”

“…In addition, this classification is supported by the topobathymetric maps published by Alves et al, (2018Alves et al, ( , 2019) that shows a submerse bank extending from the Marinheiros Island that makes the bathymetry complex, mainly at the east margin of the Cavalos Island. Sites 1P-3P and 1C-3C were considered shallow zones and sites 4P, 4C and 5C deeper zones (Modified from Ortega et al, 2018). Figura 1.…”

“…Pontos 1P-4P pertencem à área da ilha da Pólvora e os pontos 1C-5C pertencem à área da ilha dos Cavalos. Pontos 1P-3P e 1C-3C foram considerados zonas rasas e os pontos 4P, 4C e 5C zonas mais profundas (Modificado de Ortega et al, 2018).…”

Toward Ecosystem-Based Assessment and Management of Small-Scale and Multi-Gear Fisheries: Insights From the Tropical Eastern Pacific

“…Fisheries authorities in Colombia banned the use of bottom trawls more than 10 years ago (INCODER, 2004) but fishers continue to use it since there is low enforcement capacity and high market demand for the main target species (small-sized shrimp species). On the other hand, a recent study on the effects of small-scale bottom trawling in similar estuarine environments in Brazil found that observed differences in the structure of macrofaunal communities seemed to be more related to natural variability than to the degree of trawling impact (Ortega et al, 2018). These authors discussed whether those communities could be adapted to a highly dynamic and frequently disturbed estuarine environment, which could also be the case of the benthic communities in Buenaventura that have sustained a bottom trawl fishery for more than 30 years.…”