A trans-ecosystem fishery: Environmental effects on the small-scale gillnet fishery along the Río de la Plata boundary

Trophic ecology of young‐of‐the‐year elasmobranchs in a critical habitat within the Río de la Plata outer estuarine waters

“…However, it is important to highlight that the choice of gillnets as sampling method may have played a part in overestimating diet results for these two prey, which are important components in the catch of the small‐scale fishery sampled in this study (Jaureguizar et al . ). This is because sevengill sharks can feed upon entangled prey before getting caught, as observed in gillnet deployments conducted in California (Ebert 1991a) and Western Australia (Braccini ).…”

“…Fishermen use demersal gillnets (nylon 0.6 mm, mesh size 90–120 mm) to catch a range of fish resources from which at least 12 chondrichthyan species are usually caught as target or bycatch (see full list in Jaureguizar et al . ). As described by Jaureguizar et al .…”

“…As described by Jaureguizar et al . (), an average monthly fishing trip by season showed the following characteristics: distance to the coast where the nets were soaked ranged from 3443.1 ± 2048 m (spring) to 5106.7 ± 2197 m (autumn), the soak time ranged from 8.7 ± 8.1 h (winter) to 21.2 ± 4.5 h (summer) and the net length ranged from 375 ± 181.1 m (summer) to 691.6 ± 322 m (autumn).…”

“…This nearshore area undergoes seasonal influence of the Río de la Plata discharge and supports a small‐scale fishery, named as ‘trans‐ecosystem’ fishery because of the fluctuating estuarine or marine predominant conditions that define the inter‐annual variation in its catch species composition (Jaureguizar et al . ) and CPUE of at least one small shark ( Mustelus schmitti , De Wysiecki et al . ).…”

Highest catch of the vulnerable broadnose sevengill shark Notorynchus cepedianus in the south‐west Atlantic

“…Even though catches of N. cepedianus are rather rare events in the SWA, seasonal variations in its occurrence have been observed. In a recent study of gillnet fisheries across adjacent waters of Samborombón Bay, Jaureguizar et al (2015) reported that these sharks were more frequently encountered during austral spring compared with the rest of the year. Seasonal fluctuations in its abundance were also observed in Anegada Bay (40 ∘ S) and Rio Deseado (48 ∘ S), probably because N. cepedianus use these areas for breeding purposes (Lucifora et al, 2005;Cedrola et al, 2009).…”