Browsing by Author "Machado, Leonardo F."
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- Cleaning activity among Labridae in the Azores: the rainbow wrasse Coris julis and the Azorean blue wrasse Centrolabrus caeruleusPublication . Bertoncini, Áthila A.; Machado, Leonardo F.; Barreiros, João P.; Hostim-Silva, Maurício; Verani, José R.Cleaning interactions among the rainbow wrasse Coris julis and the azorean blue wrasse Centrolabrus caeruleus are presented with photographic registers, as well as the first record of the latter cleaning conspecifics from Azorean shallow rocky reefs.
- Diversity and seasonal changes in the ichthyofauna of rocky tidal pools from Praia Vermelha and São Roque, Santa Catarina, BrazilPublication . Barreiros, João P.; Bertoncini, Áthila A.; Machado, Leonardo F.; Hostim-Silva, Maurício; Santos, Ricardo S.Este trabalho realizou-se entre Abril de 1998 e Maio de 1999 e visou o estudo das comunidades de peixes em duas poças de maré situadas nas praias de Praia Vermelha (PV) e São Roque (SR), Santa Catarina, Brasil. A poça de PV é maior e mais próxima do sub-mareal. Os exemplares foram coletados mensalmente, durante a baixa-mar, com o anestésico quinaldina. Em PV recolheram-se 1287 peixes pertencentes a 19 espécies enquanto em SR foram capturados 553 peixes de 11 species. Em ambas as poças as espécies dominantes foram Bathygobius soporator (Gobiidae), Abudefduf saxatilis (Pomacentridae), Parablennius pilicornis (Blenniidae), Labrisomus nuchipinnis (Labrisomidae) e Epinephelus marginatus (Serranidae). A diversidade e o número de peixes foram maiores nos meses de Verão e correspondem a uma época de recrutamento para as espécies A. saxatilis e E. marginatus.
- Feeding ecology and trophic ontogeny in Epinephelus marginatus (Perciformes: Serranidae) from south BrazilPublication . Machado, Leonardo F.; Daros, Felippe A.; Bertoncini, Áthila A.; Hostim-Silva, Maurício; Barreiros, João P.The stomach contents of 257 specimens of Epinephelus marginatus (197-920 mm TL) obtained between February 1999 and December 2003 in Santa Catarina State (South Brazil) were investigated in order to analyse their diet composition and understand the feeding strategy and interspecific diet overlap. E. marginatus from south Brazil fed mainly on brachyuran crustaceans, followed respectively by teleost fish and cephalopods. In ontogenetic terms the importance of these groups remains practically the same and the feeding strategy also did not show significant shifts. A generalist strategy with heterogeneous feeding is present in all four size classes and the increase of nutritional requirements during the life cycle is satisfied by predating on larger prey instead of a greater number of preys. Changes in the relative importance of the main prey species and brachyuran prey size-range appear to be an important mechanism to prevent dietary niche overlap in E. marginatus from south Brazil.
- Feeding strategy and trophic ontogeny in Scorpaena maderensis (Scorpaeniformes: Scorpaenidae) from the Azores, NE AtlanticPublication . Machado, Leonardo F.; Nunes, Donzília; Ávila, Madaíl; Vieira, Rui P.; Barreiros, João P.Feeding habits of Scorpaena maderensis Valenciennes, 1833 from the Azores archipelago were investigated. The stomach contents of 245 specimens, collected between August 1997 and July 1999, were analysed. Decapod crustaceans and teleost fishes constitute the main food items, revealing a high level of specialization by S. maderensis. Ontogenic shifts and seasonal changes in the diet composition were observed, unveiling the adaptability and opportunistic predatory behaviour of this scorpaenid.
- First record of Alosa fallax (Lacépède, 1803) (Teleostei: Clupeiformes:Clupeidae) in the Azores Archipelago, Portugal (NE Atlantic)Publication . Barreiros, João P.; Vieira, Rui P.; Machado, Leonardo F.This note reports the first record of Alosa fallax (Lacépède, 1803) in the Azores Archipelago (NE Atlantic, Portugal). Being an anadromous species, this occurrence is quite unexpected since there are no suitable breeding habitats for this species in these volcanic islands, isolated and river less. Although A. fallax is known to migrate offshore, it has never been previously reported in oceanic environments. We discuss this occurrence and theorize on the possibility of the species’ being found in Madeira, another Macaronesian Archipelago, albeit much older and closer to European coasts and thus more suitable to be crossed by A. fallax during their migration routes in pelagic environments. With this record, the number of Clupeid fishes for Azorean waters increases to two, the other being the well known and resident Sardina pilchardus.
- First record of Polyprion oxygeneios (Perciformes: Polyprionidae) for the southwest Atlantic Ocean and a northernmost range extension.Publication . Barreiros, João P.; Machado, Leonardo F.; Hostim-Silva, Maurício; Sazima, Ivan; Heemstra, Phillip C.The hapuka Polyprion oxygeneios (Schneider & Foster) (Fig. 1) is an important deep-water commercial fish species, caught mainly off Australia, New Zealand, Juan Fernandez Archipelago off Chile, the Tristan da Cunha Group of the South Atlantic (Sepúlveda & Pequeño, 1986; May & Maxwell, 1986; Paulin et al., 1989; Paxton et al., 1989; Andrew et al., 1995) and incidentally caught off Chilean Patagonia (Nakamura et al., 1986). The distribution of P. oxygeneios is exclusively southern circum-global, intemperate-cold waters from 28_ to 43_ S (Paxton et al., 1989). Polyprion oxygeneios (Polyprionidae; Nelson, 1994) is mainly a demersal species with a depth range of 50–450 m, occurring over ‘rough’ ground from the central shelf to the upper slope (Paxton et al., 1989). It reaches 150 cm total length (LT) and may weigh up to 100 kg, its juveniles being found near the surface, probably associated with drifting material in a way similar to that recorded for Polyprion americanus (Bloch & Schneider) (Paxton et al., 1989; Saldanha, 1995). This paper reports the first record of P. oxygeneios from the south-west Atlantic.
- First record of Seriola fasciata, in the Azores. A northernmost occurrence in the NE AtlanticPublication . Machado, Leonardo F.; Barreiros, João P.Première capture de Seriola fasciata (Carangidae) aux Açores. Il s’agit de l’occurrence la plus septentrionale en Atlantique nord-est. Un spécimen de Seriola sp., inconnu de l’archipel des Açores, a été capturé par un chasseur sous-marin près de l’île Terceira. Après comparaison des caractères morphologiques, le spécimen a été identifié comme Seriola fasciata, espèce non encore enregistrée pour le nord-est de l’océan Atlantique au nord de Madère.
- Habitat use by the juvenile dusky grouper Epinephelus marginatus and its relative abundance, in Santa Catarina, BrazilPublication . Machado, Leonardo F.; Bertoncini, Áthila A.; Hostim-Silva, Maurício; Barreiros, João P.The dusky grouper (Epinephelus marginatus) is a species whose stock management deserves special attention. It has an important role in hard-bottom ecosystems and, as a protogynous hermaphrodite; it is especially susceptible to overfishing. Data on the species’ use of habitat, and on the way environmental and behaviour parameters influence its abundance can help to improve management and conservation strategies. The aim of this study was to evaluate the influence of bottom type, temperature and species behaviour on the abundance of E. marginatus, using a quadrate for visual census. An area of 80 mq., divided between rocky shore, rocky outcrop and sandy habitats was surveyed monthly. Densities of juveniles were: 1.16 groupers mˉ² over the rocky shore and 1.47 groupers mˉ² over the rocky outcrop, while no groupers were found over sand. Analysis of the yearly variation in abundance revealed a migratory pattern of dispersal and gathering. All size groups observed in this study were below the first maturation length.
- In situ observation of sexual reproduction of Holothuria tubulosa Gmelin 1788 (Echinodermata: Holothuroidea) in the Azores (NE Atlantic)Publication . Andrade, Áthila A.; Machado, Leonardo F.; Barreiros, João P.; Paulay, Gustav; Cardigos, Frederico[...]. In the Azores, H. tubulosa spawning occurs in the summer months (so far observed in July and August) during the afternoon, which may follow the annual pattern, during warm sea temperatures (22–26°C) and being synchronous in both sexes, as stated by Despalotovic et al. (2004) in the Adriatic Sea. [...]
- Juvenile Sphyraena viridensis, preyed by the lizard fish Synodus saurus. A new predatory association from the AzoresPublication . Barreiros, João P.; Cardigos, Frederico; Soares, Marta S. C.; Machado, Leonardo F.Les juvéniles de Sphyraena viridensis, proies de Synodus saurus, une nouvelle association prédateur-proie aux Açores. Au cours d’un travail sur l’écologie (comportement, alimentation et reproduction) du poisson lézard, Synodus saurus, aux Açores (Atlantique NE) nous avons découvert, dans plusieurs contenus stomacaux, des exemplaires postlarvaires et des juvéniles de la bécune à bouche jaune Sphyraena viridensis. Non seulement cette découverte nous a permis d’obtenir, pour la première fois, des postlarves de cette espèce de barracuda mais nous avons réussi à décrire une action de prédation d’un poisson épibenthique envers une espèce pélagique.