The model specification, results and diagnostic tests of generalised additive models (i.e. GAM plots) describing the influence of the amount of each species in the catch, the fishing location, depth and season on the amount of dead discards, slipping and total discards in the Madeiran purse-seine fishery over the 15-month period investigated. Landings of this fishery are mostly composed of blue jack mackerel Trachurus picturatus, Atlantic chub mackerel Scomber colias, and small amounts of sardine Sardina pilchardus.

The occurrences of 13 specimens belonging to 9 species of little known marine fishes in the Northeast Atlantic in 2017 and 2018 are reported. Information about the morphology and new findings of Decapterus tabl and Decapterus macarellus (Carangidae), Kyphosus vaigiensis (Kyphosidae), Remora osteochir (Echeneidae), Antigonia capros (Caproidae), Hyperoglyphe perciformis (Centrolophidae), Halobatrachus didactylus (Batrachoididae), Parapristipoma octolineatum (Haemulidae) and Zu cristatus (Trachypteridae) are reported in different locations, where they are categorized as unusual or rare. Morphometric and meristic parameters confirm the identification to species level of each specimen, also supported by DNA barcoding. Histological examination of reproductive tissue is carried out in four specimens to know the sex and their reproductive stage. All species are known from other areas of the Atlantic Ocean, but these findings are an important contribution to understanding their biology and distribution. These include a new northernmost record of Remora osteochir and Decapterus tabl in the eastern Atlantic and the first records of Antigonia capros, Hyperoglyphe perciformis, Halobatrachus didactylus and Parapristipoma octolineatum from Galician waters.

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The common bottlenose dolphin (Tursiops truncatus) is a top marine predator widely dispersed in coastal and pelagic habitats and with a generalist feeding behavior. Yet, information on the trophic ecology of animals inhabiting pelagic environments is still scarce. Using carbon (δ13C: 13C/12C) and nitrogen (δ15N: 15N/14N) stable isotope ratios, we identified and quantified the main groups of prey assimilated by bottlenose dolphins inhabiting an oceanic habitat (Madeira Island, East Atlantic). Bottlenose dolphins assimilated pelagic, schooling fish (such as blue jack mackerel, Trachurus picturatus) and mesopelagic and demersal squids, which reinforces the pelagic dietary composition of insular/oceanic dolphins. Also, intra-seasonal differences were found in their stable isotope ratios, which suggest intraspecific variability in the feeding behavior among individuals living in the same area. Sex was not the main factor contributing to these differences, suggesting the lack of trophic niche segregation between adult males and females in this offshore environment. Nonetheless, further studies including different life stages and information on the ecophysiological requirements are necessary to disclose the factors responsible for the observed variability. This study showed that insular dolphins fed primarily on economically important pelagic prey, highlighting the need of developing management strategies that integrate conservation in fisheries plans.