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The marine waters around the Azores archipelago have been studied for quite a long time. Deeper areas, however, were historically poorly accessible and only now previously unreported species are recorded regularly. Our monitoring efforts of the Azorean ichthyofauna have recently revealed two cases of indirect evidence of the presence of a cookiecutter shark ( Isistius sp.). The evidence, documented photographically, was in the form of explicit bite marks on two dolphins representing two separate species: the Atlantic spotted dolphin, Stenella frontalis (Cuvier, 1829) and the short-beaked common dolphin, Delphinus delphis Linnaeus, 1758. The two dolphins swam close to Terceira Island. No specimens have yet been collected. The shape, and size of the wounds observed suggest that they were inflicted by a cookiecutter shark. The fresh state of the injuries suggests they were sustained recently in the proximity of the Azores.

Courtship and spawning behaviors of coral reef fishes are very complex, and sufficient sampling effort and proper methods are required to draw informed conclusions on their mating systems that are grounded in contemporary theories of mate choice and sexual selection. We reviewed the recent study by Karkarey et al. (BMC Ecol 17:10, 2017) on the spawning behavior of Squaretail coralgrouper (Plectropomus areolatus) from India and found no evidence to support their findings of alternative reproductive tactics, unique school-spawning involving a single male with multiple females, or inverse size-assortment. The study lacks scientific credibility due to a lack of rigor in the methodology used, misinterpretation of observed behaviors, misinterpretation of the literature, and insufficient data. Their approach led the authors to produce spurious results and profound, invalid conclusions that violate the most basic assumptions of mate choice and sexual selection theory as applied to mating systems in marine fishes.

Pelagic octopods have secondarily left the seafloor and evolved a holopelagic existence. One of the most striking adaptations among a suite of related pelagic octopod families (superfamily Argonautoidea) is their associations with gelatinous zooplankton (jellyfishes and salps). Here, we report a unique interaction between a male octopod ( Haliphron atlanticus ) and a jellyfish ( Pelagia noctiluca ) at the sea surface. The oral-to-oral surface orientation of this encounter and sizes of the animals seem not to fit the explanations of camouflage, shelter, and/or transportation for the octopod or “weapons stealing” strategies observed to date in other pelagic octopods. While maneuvering the jelly, H. atlanticus appears to use the jelly’s marginal nematocystic tentacles for protection. This constitutes further evidence that all four octopod families of the Argonautoidea display various interactions with gelatinous zooplankton.

In recent years Azorean fishermen reported the presence of the smalltooth sand tiger shark, Odontaspis ferox (Risso, 1810), a very rare demersal shark species, associated with insular shelves and slopes, with occasional incursions into shallow waters and of poorly known biology and ecology. There are fourteen new records of this species, between 1996 and 2014, captured by spearfishing, harpoons, hand lines, or entangled in fishing gear in the Azores. These records were analysed and complemented with fishermen interviews, providing new locations and new biological data for this species. Also, specimens photographs were studied and post-mortem analysis were carefully carried out in one individual. This species is rare and captured only as bycatch in shallow waters. More detailed information on this species is critically needed in order to assess its conservation status and implement management guidelines. Bycatch statistics are crucial in this respect.

A specimen of porcupine fish was collected by a fisherman at Terceira Island, Azores (north-eastern Atlantic), and identified as the pelagic porcupinefish, Diodon eydouxii Brisout de Barneville, 1846, a species recently recorded for the first time from the Azores. This record, together with an examination of the first reported specimen, allowed us to compare the external morphology with Pacific specimens. The possibility of this species to be relatively common in the Azores is discussed.

A lutjanid recently captured in Flores Island represents the first documented record of a snapper for the Azores Islands. Since this specimen was not made available to us besides photographs and a muscle sample, a genetic study approach was necessary in order to accurately describe and discuss this somewhat unexpected occurrence. The main objective of this paper was to explain and discuss the presence of this single specimen in this part of the north-eastern Atlantic. The specimen was caught by spear fishers on 30 July 2014 off Flores Island. We analysed all available photographs and a sample of muscle tissue that was taken and preserved frozen to be used for DNA barcoding. The specimen was a reproductively mature female with a total length of 108.7 cm and weighing 14.84 kg. The body depth of the specimen from the Azores was 2.9 in SL and the analyses conducted showed no divergence from the Canary Islands specimen reported by García-Mederos and Tuset (2014) as Lutjanus dentatus (Duméril, 1861) with the body depth of 2.5 in SL, which demonstrates that this character is highly variable and not useful for species identification. The snapper specimen from the Island of Flores is a Lutjanus cyanopterus (Cuvier, 1828) and confirmed as first record for this part of the north-eastern Atlantic. Comparisons with a L. dentatus from the Canary Islands point towards synonymy although the available molecular evidence is too scarce and by no means conclusive.

A shallow-water fish assemblage, over a soft, sandy bottom, at Canto Grande, Santa Catarina, Brazil, was sampled with a beach seine. Sampling was undertaken at 3 h intervals over 24 h on a bimonthly basis between April 1996 and February 1997. There was a seasonal variation in the number of species, density of fishes and biomass with the highest values in February (38 species, 257.6 fish 1000 m−2, 2286.4 g 1000 m−2). A total of 67 species, belonging to 56 genera and 33 families were collected and the assemblage was dominated by seven species belonging to three families: Atherinella brasiliensis (Atherinidae); Brevoortia pectinata, Harengula clupeola and Sardinella brasiliensis (Clupeidae); Anchoviella lepidontostole, Cetengraulis edentulus and Lycengraulis grossidens (Engraulidae). Species diversity (H′) and equitability (J′) were medium to high throughout the year due to the low dominance. The largest change in the assemblage structure occurred between winter months (July and August) and the other seasons. None of the dominant species can be classified as a resident. Main predators were Pomatomus saltator (winter) and Trichiurus lepturus (summer). Most of the species observed were either juvenile fish or small pelagic and strongly gregarious species.

A shallow-water fish assemblage, over a soft, sandy bottom, at Canto Grande, Santa Catarina, Brazil, was sampled at bimonthly intervals with a beach seine. Sampling was undertaken at 3 h intervals over 24 h on a bimonthly basis between April 1996 and February 1997. Each monthly set of samples was divided into day and night catches. A total of 67 species, belonging to 56 genera and 33 families, were collected. From these, ten occurred only in the day catches and 18 only at night. There was seasonal variation and day/night differences in the number of species (49/57), density of fishes (63.3/62.4 fish 1000 m⁻²). and biomass (316.3/626.9 g 1000 m⁻²). The highest values occurred in summer night samples (182.1 fish 1000 m⁻², 1893.0 g 1000 m⁻²). In terms of density both day and night catches were dominated by Lycengraulis grossidens while in terms of biomass day catches were dominated by Harengula clupeola and night catches by Trichiurus lepturus. Despite a slight tendency for greater night values, species diversity (H') and evenness (J') were not significantly different between the two periods. The largest change in the assemblage structure occurred between winter months (July and August) and the other seasons, especially due to the distribution of the main predators found Pomatomus saltator (winter and night) and Trichiurus lepturus (summer and night). Most of the species observed were either juvenile fish or small pelagic and strongly gregarious species. A comunidade de peixes de fundos móveis arenosos de Canto Grande, Santa Catarina, Brasil, foi estudada por amostragens bimensais com recurso a redes de praia. As amostragens realizaram-se durante períodos de 24 h com intervallos de 3 h, numa base bimensal entre Abril de 1996 e Fevereiro de 1997. Cada conjunto mensal de amostras foi dividido em capturas diurnas e nocturnas. Colectaram-se 67 espécies de peixes, correspondendo a 56 géneros e 33 famílias. De entre estas espécies, 10 ocorreram apenas de dia e 18 exclusivamente de noite. Verificou-se uma variação sazonal e diferênças dia/noite no número de espécies (49/57), densidade de peixes (63.3/62.4 peixes 1000 m⁻²) e biomassa (316.3/626.9 g 1000 m⁻²). Os valores mais elevados verificaram-se nas amostras nocturnas de Verão (182.1 peixes 1000m⁻², 1893.0 g 1000m⁻²). Em termos de densidade, tanto as amostras diurnas como as nocturnas foram dominadas por Lycengraulis grossidens enquanto que em termos de biomassa as amostras diurnas forma dominadas por Harengula clupeola e as nocturnas por Trichiurus lepturus. Apesar de se notar uma certa tendência para valores nocturnos mais elevados, a diversidade (H') e equitabilidade (J') não foram significativamente diferentes entre os valores de dia e de noite. A maior variação na estrutura da comunidade ocorreu entre os meses de Inverno (Julho e Agosto) e as outras estações, devido sobretudo à distribuição dos principais predadores Pomatomus saltator (Inverno e noite) e Trichiurus lepturus (Verão e noite). A maior parte das espécies observadas foram juvenis ou pequenos peixes pelágicos fortemente gregários.

Although global biodiversity is declining, local ecosystems are not systematically losing diversity, but rather experiencing rapid turnover in species.