Article

Visual observations of fish from seamounts of the Southern Azores Region (the Atlantic Ocean)

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Abstract

Results of observations from the underwater inhabited device “Sever-2” of the behavior and distribution of fish on seamounts of the Azores region up to a depth of 1200 m are provided. In the natural habitat, 52 species of fish of 46 genera belonging to 36 families were recorded. In the ichthyofauna of the studied region, bottom (37.0%) and near-bottom (29.2%) species dominate; the proportion of off-bottom and off-bottom-pelagic species is 18.0 and 12.4%, respectively, and pelagic species account for only 3.4%. Pelagic species Scomber japonicus and Trachurus picturatus; off-bottom-pelagic Beryx splendens, Lepidopus caudatus, and Aphanopus carbo; and near-bottom species Zenopsis conchifer, Macrorhamphosus scolapax, Antigonia capros, Capros aper, Anthias anthias, and Callanthias ruber dominate by numbers and the amount of biomass.

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... Contrary to the relatively well-known fish fauna of seamounts and islands around the Azores and Madeira (Arkhipov et al. 2004;Christiansen et al. 2009;Ehrich 1977;Kukuev 2004;Maul 1976;Menezes et al. 2006Menezes et al. , 2009Menezes et al. , 2012Pakhorukov 2008;Santos et al. 1997;Shcherbachev et al. 1985), the ichthyofauna of the Horseshoe Seamount Chain (Fig. 1) and in particular of Ampère Seamount has been little studied until now. Visual observations were conducted on the summit area of Gorringe Bank (Abecasis et al. 2009;Gonçalves et al. 2004) and on the upper and middle slopes at Ampère Seamount and Josephine Bank; the latter was also trawled (Pakhorukov 2008). ...
... Contrary to the relatively well-known fish fauna of seamounts and islands around the Azores and Madeira (Arkhipov et al. 2004;Christiansen et al. 2009;Ehrich 1977;Kukuev 2004;Maul 1976;Menezes et al. 2006Menezes et al. , 2009Menezes et al. , 2012Pakhorukov 2008;Santos et al. 1997;Shcherbachev et al. 1985), the ichthyofauna of the Horseshoe Seamount Chain (Fig. 1) and in particular of Ampère Seamount has been little studied until now. Visual observations were conducted on the summit area of Gorringe Bank (Abecasis et al. 2009;Gonçalves et al. 2004) and on the upper and middle slopes at Ampère Seamount and Josephine Bank; the latter was also trawled (Pakhorukov 2008). Recently, Wienberg et al. (2013) reported some fish species at Coral Patch Seamount from ROV observations above the middle slope. ...
... The results presented here increase the number of fish species described from Ampère seamount substantially. Most of the 34 species collected at and around the Christiansen et al. (2009), Ehrich (1977, Menezes et al. (2009), Pakhorukov (2008, Shcherbachev et al. (1985) JB Josephine Bank, GB Gorringe Bank, SS Seine Seamount, SSAz seamounts south of the Azores a See remark in Table 2 Helgol Mar Res (2015) 69: 13-23 19 seamount in this study are widely distributed in the Atlantic and in the Mediterranean (e.g. Froese and Pauly 2013;Haedrich and Merrett 1988;Menezes et al. 2006Menezes et al. , 2009Menezes et al. , 2012Merrett 1992;Merrett and Marshall 1981;Pakhorukov 2008). ...
Article
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An inventory of benthic and benthopelagic fishes is presented as a result of two exploratory surveys around Ampère Seamount, between Madeira and the Portuguese mainland, covering water depths from 60 to 4,400 m. A total of 239 fishes were collected using different types of sampling gear. Three chondrichthyan species and 31 teleosts in 21 families were identified. The collections showed a vertical zonation with little overlap, but indications for an affinity of species to certain water masses were only vague. Although most of the species present new records for Ampère Seamount, all of them have been known for the NE Atlantic; endemic species were not found. The comparison with fish communities at other NE Atlantic seamounts indicates that despite a high ichthyofaunal similarity, which supports the “stepping stone” hypothesis of species dispersal, some differences can be attributed to the local features of the seamounts.
... Seamounts are also known to provide habitat and foraging ground for fishes, including commercial species. Several studies have characterized the seamount ichthyofauna in regions of the temperate NE Atlantic (e.g., Pakhorukov 2008;Menezes et al. 2009Menezes et al. , 2012Christiansen et al. 2014). Knowledge of the distribution patterns of bathyal and abyssal fish species, however, is generally poor. ...
... Antigonia capros 1 BT Summit 100 SL 17.5 This is the first record for Senghor Seamount, but the species has been caught before in the Cape Verde area at several stations close to the islands (Strømme et al. 1982). The species was common on the Great Meteor Bank and other seamounts south of the Azores (Ehrich 1977;Shcherbachev et al. 1985;Pakhorukov 2008), and at Ampère and Josephine in the Horseshoe seamount chain (Pakhorukov 2008), but has not been reported from the NE Atlantic seamounts Seine, Sedlo and Gorringe (Abecasis et al. 2009;Menezes et al. 2009;Menezes et al. 2012 were reported to occur in the greater Cape Verde region (Trunov et al. 2006;Stevenson and Kenaley 2011;Kukuev et al. 2012). ...
... Antigonia capros 1 BT Summit 100 SL 17.5 This is the first record for Senghor Seamount, but the species has been caught before in the Cape Verde area at several stations close to the islands (Strømme et al. 1982). The species was common on the Great Meteor Bank and other seamounts south of the Azores (Ehrich 1977;Shcherbachev et al. 1985;Pakhorukov 2008), and at Ampère and Josephine in the Horseshoe seamount chain (Pakhorukov 2008), but has not been reported from the NE Atlantic seamounts Seine, Sedlo and Gorringe (Abecasis et al. 2009;Menezes et al. 2009;Menezes et al. 2012 were reported to occur in the greater Cape Verde region (Trunov et al. 2006;Stevenson and Kenaley 2011;Kukuev et al. 2012). ...
Article
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Senghor Seamount is an important fishing ground around the Cape Verde archipelago in the Eastern Central Atlantic. On an experimental field survey in October 2009 and December 2011, a total of 115 deep-sea fishes of 26 species belonging to 18 families were caught on the seamount summit, along the slopes and on the adjacent abyssal plane, using longlines, fish traps, beam trawl and otter trawl. Here we report seven new records for the Cape Verde deep-sea fish fauna. Most species are known from other areas of the Atlantic Ocean, but our findings are an important contribution to our understanding of the distribution of deep-water fish species. The co-occurrence of northern and southern Atlantic ichthyofauna components at Senghor Seamount, and the Cape Verde area in general, can be attributed to the large-scale hydrographic regime with two water masses merging at the Cape Verde Frontal Zone, the North Atlantic Central Water and the South Atlantic Central Water.
... Bluemouth adults are thought to lead a very sedentary life style according to seabed observations and tagging experiments. Between 1982 and 1986, a series of visual observations and trawls performed by R/V Ikhtiandr were carried out to study the ichthyofauna on seamounts of the Southern Azores complex (Pakhorukov, 2008). ...
... Thus, the bluemouth populations from the Porcupine Bank (n = 182) and Alicante (n = 134) were used to compare the success of the five methods in eliminating the size effect on shape variables. These populations were assumed to belong to different stocks based on a) the considerable geographical distance that separates the sampling locations, b) characteristics of the bluemouth such as adult sedentarism (Uiblein et al., 2003;Pakhorukov, 2008) and c) the environment in these locations, for example, the closed circulation patterns in the Porcupine Bank (White et al., 2005) and existence of possible oceanographic barriers such as the Strait of Gibraltar or the Almería-Oran Front (Tintoré et al., 1988). ...
... (1) Isolation (at least partially) due factors like boundary effects of biogeographical limits (e.g., the Strait of Gibraltar between the NE Atlantic and Mediterranean), the species' sedentary behavior (Uiblein et al., 2003, Pakhorukov, 2008, a limited larval dispersal in the pelagic stage (Aboim, 2005) and the geographical distance existing between the different study areas. ...
... A few studies have been carried out on the blue jack mackerel from the Eastern Central Atlantic, including Madeira (Jesus, 1992;Vasconcelos et al., 2006;Faria and Vasconcelos, 2008) and the Azores (Isidro, 1990;Arkhipov et al., 2002;Arkhipov and Mamedov, 2008;Pakhorukov, 2008). Biological studies of T. picturatus from the Canary Islands have been scarce, limited to some information included in technical reports and a few studies from the region (Shaboneyev and Ryazantseva, 1977;Delgado et al., 1983;Bordes et al., 1987;Rivero, 2006;Jurado-Ruzafa and Santamarı´a, 2011). ...
... Predominance of undetermined individuals agreed with the determined recruitment season off Canary Islands between August and December (Jurado-Ruzafa and Santa-marı´a, 2011). Variations in the predominance of males and females could be explained by the ecological behaviour of the species (Arkhipov et al., 2002;Menezes et al., 2006;Pakhorukov, 2008), owing to the fact that females spawn on the ground and are not catchable by fishing gear during spawning season (in winter-spring) as occurs in related species (Abaunza et al., 2003). Planktonic studies have observed these strong trends in the region, being that T. picturatus (Moyano, 2009;). ...
... In further studies it would be interesting to analyse a time period in which spawning events occur in the mid-term, in order to elucidate whether it is one or two differentiable events. On the other hand, results off the Canary Islands differ with the results in the Mediterranean Sea and from the seamounts of the Azores region, where T. picturatus spawns in summer (Lloris and Moreno, 1995;Pakhorukov, 2008), despite Arkhipov et al. (2002) described another spawning peak in the winter season around seamounts of the South-Azores archipelago. ...
Article
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The reproductive cycle of the blue jack mackerel, Trachurus picturatus, had not been described for the Canary Islands. Between March 2005 and March 2006 monthly samples of T. picturatus were collected randomly at the central fishery wharf from the commercial catches of purse-seiners in Tenerife Island waters (Canary Islands). Some 2472 specimens were analysed, with total lengths from 10.4 to 31.9 cm. Although females outnumbered males in summer, males were more abundant in the sex ratio (1.36 : 1). Based on the monthly evolution of the gonado-somatic index and the proportion of mature individuals, the spawning season occurred between January and April, peaking in February. Lengths at first maturity (LFM) were calculated from the maturity ogives by the Gompertz model for all specimens (22.79 cm), for males (21.20 cm) and for females (23.05 cm). In this area the minimum legal size for T. picturatus is actually smaller than the length at first maturity and should be revised to avoid depletion of the stock.
... The near-surface AC forms a meandering pattern directed eastwards with main branches flowing towards Gibraltar to the north and towards the Canary Islands to the south (Johnson and Stevens, 2000) that affects the Josephine Seamount area. The region around the Josephine Seamount is also influenced by the northeastern part of the sub-tropical gyre, whose eastern periphery is the CC (Pakhorukov, 2008). The mesopelagic zone is under the influence of the intermediate North Atlantic water mass (Pakhorukov, 2008), and deeper, under the North Atlantic water. ...
... The region around the Josephine Seamount is also influenced by the northeastern part of the sub-tropical gyre, whose eastern periphery is the CC (Pakhorukov, 2008). The mesopelagic zone is under the influence of the intermediate North Atlantic water mass (Pakhorukov, 2008), and deeper, under the North Atlantic water. Between them, the Mediterranean water flows in the form of long-lived subsurface vortices known as ''meddies'' (Richardson et al., 2000;Pakhorukov, 2008). ...
... The mesopelagic zone is under the influence of the intermediate North Atlantic water mass (Pakhorukov, 2008), and deeper, under the North Atlantic water. Between them, the Mediterranean water flows in the form of long-lived subsurface vortices known as ''meddies'' (Richardson et al., 2000;Pakhorukov, 2008). ...
Article
Full-text available
Mesopelagic organisms play an important role in the vertical carbon flux through diel vertical migrations. The mesopelagic fauna of three NE Atlantic seamounts (Gorringe Bank, Josephine and Seine) and surrounding oceanic waters were sampled. Echogram scrutiny suggests a diel vertical migration of the mesopelagic fauna. Muggiaea atlantica and Meganyctiphanes norvegica were caught at almost every station and thus, appeared to be ubiquitous. Several taxa were only caught in open oceanic stations (e.g. Lampanyctus alatus, Deosergestes corniculum and Acanthephyra purpurea) whereas others appeared uniquely in the vicinity of the seamounts (e.g. Lophogaster sp., Systellapsis pelucida and most of the cephalopod species). Multivariate analyses, based on presence-absence data, indicated significant differences in the mesopelagic community structure among the different seamounts, and between oceanic and seamount waters. Higher species richness was found in oceanic waters compared to seamounts. No significant relationship was found between the environmental variables salinity and fluorescence and the biological data. Even so, the values of these oceanographic parameters over the seamounts are different from those in oceanic waters. Knowledge of diversity and distribution of mesopelagic fauna will improve our understanding of the pelagic realm.
... The near-surface AC forms a meandering pattern directed eastwards with main branches flowing towards Gibraltar to the north and towards the Canary Islands to the south (Johnson and Stevens, 2000) that affects the Josephine Seamount area. The region around the Josephine Seamount is also influenced by the northeastern part of the sub-tropical gyre, whose eastern periphery is the CC (Pakhorukov, 2008). The mesopelagic zone is under the influence of the intermediate North Atlantic water mass (Pakhorukov, 2008), and deeper, under the North Atlantic water. ...
... The region around the Josephine Seamount is also influenced by the northeastern part of the sub-tropical gyre, whose eastern periphery is the CC (Pakhorukov, 2008). The mesopelagic zone is under the influence of the intermediate North Atlantic water mass (Pakhorukov, 2008), and deeper, under the North Atlantic water. Between them, the Mediterranean water flows in the form of long-lived subsurface vortices known as ''meddies'' (Richardson et al., 2000;Pakhorukov, 2008). ...
... The mesopelagic zone is under the influence of the intermediate North Atlantic water mass (Pakhorukov, 2008), and deeper, under the North Atlantic water. Between them, the Mediterranean water flows in the form of long-lived subsurface vortices known as ''meddies'' (Richardson et al., 2000;Pakhorukov, 2008). ...
Conference Paper
Conservation and ecosystem fishery management on seamounts require good understanding of distribution patterns and assemblage of the mesopelagic fauna, which have a key role linking the oceanic and the neritic realm of seamounts, functioning as food source for epipelagic and demersal organisms. Mesopelagic fauna of three NE Atlantic seamounts (Gorringe Bank, Josephine and Seine) was sampled using an Isaacs-Kidd Midwater Trawl (IKMT) and acoustic records. A total of 97 taxa were identified: 52 crustaceans, 33 fish, 6 molluscs and 6 gelatinous organisms, belonging to 37 families. The siphonophore Muggiaea atlantica and the micronektonic crustacean Meganyctiphanes norvegica were caught at almost every station and thus, appeared to be ubiquitous. Several taxa were only caught in open oceanic stations (e.g. the fish Lampanyctus alatus, and the decapod crustaceans, Deosergestes corniculum and Acanthephyra purpurea) whereas other appeared uniquely in the vicinity of the seamounts (such as the crustaceans Lophogaster sp., Systellapsis pelucida and most of the cephalopod species). Multivariate analyses, based on presence-absence data, did not show significant differences among seamounts, day and night or position on the water column, neither detected seamount effect. However, some influence of the three NE Atlantic seamounts studied on the mesopelagic community was detected because higher biodiversity was found in oceanic waters compared to seamounts. In this work, the acoustic signal produced by mesopelagic organism was weakly detected by the echo sounder, probably due to a low level of aggregation of the mesopelagic resonant organisms. Echogram scrutiny suggests a diel vertical migration of the mesopelagic fauna.
... Considering the current number of species reported so far, the Condor seems to harbor more fish species than Seine Menezes et al., 2009), Great Meteor Seamount (Fock et al., 2002a;Uiblein et al., 1999) and other south Azores seamounts (Kukuev, 2004;Pakhorukov, 2008;Shcherbachev et al., 1985), which have summits within the same depth range and were intensively sampled. The observed discrepancy is not easily explained, and falls out of the scope of this work. ...
... Rex et al., 2005), deserving further research. Nevertheless, the fauna from Condor includes many species also known from seamounts south of the Azores and Seine (Menezes et al., 2009;Pakhorukov, 2008;Uiblein et al., 1999), showing the close biogeographic affinities shared by these seamounts within the Macaronesia (Menezes et al., 2006), a subregion of the Lusitania-Mediterranean province in the Northeast Atlantic (e.g. Briggs and Bowen, 2012). ...
... Zooplanktivorous fish are common on the summits of shallow and intermediate subtropical Northeast Atlantic seamounts (i.e. Christiansen et al., 2009;Fock et al., 2002a,b;Kukuev, 2004;Pakhorukov, 2008;Shcherbachev et al., 1985;Uiblein et al., 1999). These fish are expected to occur where the supply of potential prey is abundant and predictable. ...
Article
Distribution of fish assemblages and habitat associations of demersal fishes on the Condor seamount were investigated by analyzing in situ video imagery acquired by the Remotely-Operated Vehicles ROV SP 300 and Luso 6000. A total of 51 fish taxa from 32 families were inventoried. Zooplanktivores (10 species) were the most abundant group followed by carnivores (23 species) and benthivores (18 species). Non-metric multidimensional scaling (MDS) analyses were performed on dive segments to visualize the spatial relationships between species and habitat type, substrate type or depth, with depth being the most significant parameter influencing fish distribution. Four major fish groups were identified from their vertical distribution alone: summit species (generally to <300 m depth); broad ranging species (ca. 200 to 800 m); intermediate ranging slope species (ca. 400 m to 800–850 m); and deeper species (800–850–1100 m). The fish fauna observed at the summit is more abundant (15.2 fish/100 m2) and habitat-specialized than the fish observed along the seamount slope. Down the seamount slope, the summit fish assemblage is gradually replaced as depth increases, with an overall reduction in abundance. On the summit, three species (C. ruber, A. anthias and L. fasciata) had higher affinity to coral habitats compared to non-coral habitats. A coherent specialized fish assemblage associated to coral habitats could not be identified, because most species were observed also in non-coral areas. On the seamount's slope (300–1100 m), no relationship between fish and coral habitats could be identified, although these might occur at larger scales. This study shows that in situ video imagery complements traditional fishing surveys, by providing information on unknown or rarely seen species, being fundamental for the development of more comprehensive ecosystem-based management towards a sustainable use of the marine environment.
... The purpose of this study was to assess body shape variation among bluemouth and determine putative populations around the Iberian Peninsula (NE Atlantic and Mediterranean) and their relationships. It was hypothesized that the structure of bluemouth populations is affected by: (1) boundary effects of biogeographical limits (e.g., the Strait of Gibraltar), (2) the species' sedentary behavior (Uiblein et al., 2003;Pakhorukov, 2008), (3) a limited larval dispersal in the pelagic stage (Aboim, 2005) and (4) the geographical distance existing between the different study areas. ...
... These banks are also known to be retention areas for eggs and larvae (Dransfeld et al., 2009), which could promote isolation of the bluemouth population from the Porcupine Bank, especially when its biology is also taken into account. Adult specimens of bluemouth are thought to be sedentary (Uiblein et al., 2003;Pakhorukov, 2008;Aboim, 2005 and references therein), its reproduction involves internal fertilization and zygoparity (Muñoz et al., 1999) and the larval dispersive phase is generally not sufficient to allow gene-flow between distant bluemouth populations (Aboim, 2005). However, more samples from locations in between would be needed to see if bluemouth follow a gradient of morphological variation or if there is a clear boundary between these populations. ...
Article
The bluemouth, Helicolenus dactylopterus (Delaroche 1809), is a marine demersal fish that is widely distributed in the Atlantic and the Mediterranean. It is targeted by longline fisheries around the Iberian Peninsula and it is a common by-catch associated with many demersal fisheries. However, limited information exists about the population structure in the NE Atlantic and Mediterranean. Thus, the bluemouth population structure in these regions was studied using a landmark-based geometric morphometric analysis. The purpose was to assess body shape variation among bluemouth and determine putative populations and their relationships. Three populations were identified in the western Mediterranean: two populations in the Alboran basin and another in the northwestern basin (Balearic Sea and Catalonian coast). The population from the central Mediterranean did not seem to be effectively connected to the populations in the western Mediterranean. In the NE Atlantic, our results showed that at least four different bluemouth populations exist in the following areas: Galicia-Cantabrian Sea, Peniche (Portugal), the Gulf of Cadiz and the Porcupine Bank. A connection between bluemouth from the NE Atlantic and Mediterranean was observed, making unlikely that the Strait of Gibraltar acts as a barrier isolating Atlantic and Mediterranean bluemouth populations. The results of this study provide evidence that different bluemouth populations exist, which is relevant for stock assessment and management of this species.
... Due to their more or less isolated location, these structures can be an obstacle to the free circulation of the oceans. This gives rise to different kinds of phenomena and disturbances, including an increase in the speed of sea currents, upwellings, turbulence, Taylor cones, eddies, and even jets in the zones where the seamounts interact with ocean currents (Richardson et al 2000;Kunze & Llewellyn Smith, 2004;White et al., 2007;Pakhorukov, 2008). ...
... Josephine seamount is one of Lusitanian seamounts and represents the westernmost point of east-west trending series of banks and seamounts separating the Tagus and Horseshoe Abyssal Plains also known as Horseshoe seamount chain. It is located to the east of the Mid-Atlantic Ridge and is a component of the Azores-Gibraltar complex (Pakhorukov, 2008). It is oval-shaped with a minimum water depth of 170 m at the southern end and almost flat top surface of ~150 km 2 within the 400m depth contour and ~210 km 2 within the 500m depth contour. ...
Preprint
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in less than 150 words) Madeira-Tore EBSA includes a total of 17 seamounts. Seamounts are hotspots of marine life and in general they represent areas of an enhanced productivity, especially when compared with nearby abyssal areas. This EBSA has a total area of 197431 km 2 with depths ranging from 25m (top of Gettysburg seamount) to 4930m (bottom of Tore seamount). The area includes a proposed Site of Community Importance-Gorringe Bank and an OSPAR High Seas Marine Protected Area-Josephine seamount. All structures included in the Madeira-Tore EBSA fulfill four or more out of the seven EBSA scientific criteria. A total of 965 species are present in this EBSA of which 7% are protected under international or regional law.
... Due to their more or less isolated location, these structures can be an obstacle to the free circulation of the oceans. This gives rise to different kinds of phenomena and disturbances, including an increase in the speed of sea currents, upwellings, turbulence, Taylor cones, eddies, and even jets in the zones where the seamounts interact with ocean currents (Richardson et al 2000;Kunze & Llewellyn Smith, 2004;White et al., 2007;Pakhorukov, 2008). ...
... Josephine seamount is one of Lusitanian seamounts and represents the westernmost point of east-west trending series of banks and seamounts separating the Tagus and Horseshoe Abyssal Plains also known as Horseshoe seamount chain. It is located to the east of the Mid-Atlantic Ridge and is a component of the Azores-Gibraltar complex (Pakhorukov, 2008). It is oval-shaped with a minimum water depth of 170 m at the southern end and almost flat top surface of ~150 km 2 within the 400m depth contour and ~210 km 2 within the 500m depth contour. ...
Technical Report
Full-text available
in less than 150 words) Madeira-Tore EBSA includes a total of 17 seamounts. Seamounts are hotspots of marine life and in general they represent areas of an enhanced productivity, especially when compared with nearby abyssal areas. This EBSA has a total area of 197431 km 2 with depths ranging from 25m (top of Gettysburg seamount) to 4930m (bottom of Tore seamount). The area includes a proposed Site of Community Importance-Gorringe Bank and an OSPAR High Seas Marine Protected Area-Josephine seamount. All structures included in the Madeira-Tore EBSA fulfill four or more out of the seven EBSA scientific criteria. A total of 965 species are present in this EBSA of which 7% are protected under international or regional law.
... Research on seamount fish communities has been conducted in various locations within the OSPAR area, in particular around the Azorean and Meteor seamounts and along the Iberian margin (e.g. Menezes et al., 2006Menezes et al., , 2009Pakhorukov, 2008). Depending on the depth of the seamount, the dominant species are typical deep-sea fish (bathydemersal or bathypelagic) or more shallow species (demersal or benthopelagic). ...
... Compared to geological exploration, early ecological research in the Mediterranean Sea has been sparse: only a few publications are available from the last century (e.g. Perrone, 1982;Strusi et al., 1985;Galil and Zibrowius, 1998). However, recent studies regarding seamount ecology reflect a growing interest for this field in the Mediterranean (e.g. ...
Article
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This work aims at characterising the seamount physiography and biology in the OSPAR Convention limits (northeast Atlantic Ocean) and Mediterranean Sea. We first inferred potential abundance, location and morphological characteristics of seamounts, and secondly, summarized the existing biological, geological and oceanographic in situ research , identifying examples of well-studied seamounts. Our study showed that the seamount population in the OSPAR area (northeast Atlantic) and in the Mediterranean Sea is large with around 557 and 101 seamount-like features, respectively. Similarly, seamounts occupy large areas of about 616 000 km 2 in the OSPAR region and of about 89 500 km 2 in the Mediterranean Sea. The presence of seamounts in the northeast Atlantic has been known since the late 19th century , but overall knowledge regarding seamount ecology and geology is still relatively poor. Only 37 seamounts in the OSPAR area (3.5 % of all seamounts in the region), 22 in the Mediterranean Sea (9.2 % of all seamounts in the region) and 25 in the northeast Atlantic south of the OSPAR area have in situ information. Seamounts mapped in both areas are in general very heterogeneous, showing diverse geophys-ical characteristics. These differences will likely affect the biological diversity and production of resident and associated organisms.
... Resource partitioning through differences in the vertical feeding position was suggested by gut contents and fatty acid biomarkers and is supported by studies on the distribution of fish species at seamounts (Ehrich 1974;Kukuev 2004;Pakhorukov 2008). Near-bottom fish species had higher proportions of oncaeid copepods in their stomachs, whereas calanoid copepods were more abundant in the diet of the more pelagic C. cirrus. ...
... Trophic links taken from the literature are represented by grey arrows. Investigated fish species are listed according to their vertical habitat categories derived from Pakhorukov (2008), Kukuev (2004) and Ehrich (1974). Pelagic organisms that undertake pronounced diel vertical migrations (DVM) are denoted by cross-hatched boxes. ...
Article
Several hypotheses exist about the trophic mechanisms that support fish stocks at seamounts. This study investigated the diets of benthopelagic fish species on the summit plateau of Seine Seamount (NE Atlantic), testing the sound-scattering layer interception hypothesis. A combined approach of gut content, stable isotopes and fatty-acid biomarker analyses was employed. Fish species included zooplanktivores, benthivores, piscivores and species with mixed crustacean/cephalopod/fish diets. Trophic coupling between pelagic food sources and benthopelagic fish consumers was apparent based on three main lines of evidence: (i) dominance of pelagic prey in the guts of zooplanktivores, (ii) stable isotope enrichment of consumers indicative of a pelagic prey source, and (iii) high proportions of fatty acids that are typical of phytoplankton and zooplankton in the storage lipids of fishes and their similarity with fatty acid signatures of pelagic prey. Elevated levels of arachidonic acid in a benthivorous species suggested a minor dietary contribution of rhodophytes. The lack of larger taxa that undergo diel vertical migrations in the fish guts suggests that it is horizontal fluxes of non-, or weakly migrating zooplankton that are the main food supply to the resident fish consumers. Overall, there was no unambiguous support for the trophic blockage hypothesis. Differences in gut contents, trophic position and storage lipid fatty acid signatures of zooplanktivorous fishes indicate some degree of resource partitioning with respect to feeding habitats, prey selection and ontogenetic diet shifts. Irrespective of body size and feeding mode, the benthopelagic fishes occupied intermediate trophic positions between the 3rd and 4th trophic level in a food web composed mainly of omnivorous species.
... In the Western Indian Ocean, it is reported from India to South Africa but not in the Red Sea (Froese & Pauly, 2012). It is found near the bottom or in mid–waters and near seamounts (Pakhorukov, 2008) at depths between 100 and 600 m, but mainly between 200 and 300 metres. It reaches a size of up to 75 cm standard length (Quéro, 1986) and 80 cm TL (Quigley, 2004). ...
Article
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On the occurrence of Zenopsis conchifer (Lowe, 1852) (Osteichthyes, Zeidae) in the Mediterranean Sea.- The capture of four specimens of Silvery John Dory (Zenopsis conchifer), a species recorded in the Mediterranean Sea for the first time in 2006, is reported from the Iberian coast (western Mediterranean). One of the specimens was caught near the Strait of Gibraltar and is probably a vagrant. Despite these catches, there is no evidence of a self- sustaining population, so this species should be considered as alien in the Mediterranean.
... Seamount fish communities have been studied in about 34 seamounts in the north-east Atlantic and about 9 in the Mediterranean Sea. Research on seamount fish communities has been conducted in various locations within the OSPAR area, in particular around the Azorean and Meteor seamounts and along the Iberian margin (e.g.Menezes et al., 2006Menezes et al., , 2009Pakhorukov, 2008). Depending on the depth of the seamount, the dominant species are typical deep-sea fish (bathydemersal or bathypelagic) or more shallow species (demersal or benthopelagic). ...
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This work aims at characterising the seamount physiography and biology in the OSPAR Convention limits (north-east Atlantic Ocean) and Mediterranean Sea. We first inferred potential abundance, location and morphological characteristics of seamounts, and secondly, summarized the existing biological, geological and oceanographic in situ research, identifying examples of well-studied seamounts. Our study showed that the seamount population in the OSPAR area (north-east Atlantic) and in the Mediterranean Sea is large with around 557 and 101 seamount-like features, respectively. Similarly, seamounts occupy large areas of about 616 000 km2 in the OSPAR region and of about 89 500 km2 in the Mediterranean Sea. The presence of seamounts in the north-east Atlantic has been known since the late 19th century, but overall knowledge regarding seamount ecology and geology is still relatively poor. Only 37 seamounts in the OSPAR area (3.5% of all seamounts in the region), 22 in the Mediterranean Sea (9.2% of all seamounts in the region) and 25 in the north-east Atlantic south of the OSPAR area have in situ information. Seamounts mapped in both areas are in general very heterogeneous, showing diverse geophysical characteristics. These differences will likely affect the biological diversity and production of resident and associated organisms.
... This could suggest that the slickhead species were attracted to light given off by bioluminescent animals encountering the trawl gear as it progressed. However, the precise nature of this attraction is unclear, as slickheads appear to avoid submersibles (Pakhorukov, 2008;Pakhorukov and Parin, 2011), and are not commonly seen at baited landers (Trenkel et al., 2004;Preide et al., 2012;Zintzen et al., 2012). Further evidence for optically based foraging is that P. atlanticum is strongly bioluminescent (Herring, 1987), and these were food of both Alepocephalus species from northeastern Chatham Rise. ...
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The food and feeding relationships of mid-slope slickheads in New Zealand waters are little known compared with those from the northern hemisphere. This study examines the feeding relationships of three common slickhead species from approximately 1000 m on Chatham Rise, New Zealand: Alepocephalus antipodianus (Parrot, 1948), A. australis (Barnard, 1923), and Xenodermichthys copei (Gill, 1884). The Alepocephalus species were predominantly benthopelagic feeders with a small benthic component to their diets. Alepocephalus australis fed on pelagic tunicates, notably Pyrosoma atlanticum Péron, 1804. Alepocephalus antipodianus fed on fish and pelagic tunicates, and also crustaceans. Xenodermichthys copei fed primarily on crustaceans. Considerable material was recovered from the intestines of all three species, and much of it was identifiable and only partially digested, including the remains of pelagic tunicates. There was little dietary overlap between the stomach contents of the three slickhead species indicating a degree of niche partitioning. Intestinal contents differed from stomach contents in weight, but not in number of items for all three species. The composition of stomach and intestinal contents differed for A. australis, but not for A. antipodianus or X. copei, which suggests that intestinal contents could be potentially useful in lieu of stomach content. There was a high level of overlap between the intestinal contents of A. antipodianus and A. australis, suggesting a possible closer dietary relationship between these two species than that indicated by stomach contents alone. Despite limitations in sample size and spatial and temporal coverage, the results from this study indicate that the three slickhead species could play an important role in the structuring of the demersal community at mid-slope depths on northeastern Chatham Rise.
... Behavior: Visual observations from the UID (underwater inhabited device) "Server-2", made in the 1980s at the seamounts of the Azores region, reported that this species was sighted on the Meteor Seamount at a depth of 360-460 m lying motionless on the bottom at sites with rocky outcrops, more seldom on sandy seafloor; only at a photoflash did they break away to swim short distances (0.2-0.5 m), moving aside from the UID (Pakhorukov, 2008). This species probably ambushes passing prey at the sea bottom. ...
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In this second paper dedicated to report on deep-sea fishes from Brazilian waters, mainly from Bahia, the presence of one family and three species of Aulopoidei is reported for the first time from Brazilian waters: the aulopid Aulopus filamentosus (royal flagfin), the synodontids Saurida normani and Synodus poeyi (shortjaw lizardfish and offshore lizardfish, respectively). The presence of Synodus saurus and Saurida suspicio in Brazilian waters is discussed, and a key to the Western Atlantic Aulopoidei is provided.
... Such conjecture is also supported by the connectivity role of the overall hydrodynamic circulation of the Mediterranean Sea, characterized by a superficial flow (Modified Atlantic Water (MAW)), from the western to the eastern side and a counter-flow (Levantine Intermediate Water (LIW)) of more saline, deeper water from the eastern to the western basin (Millot et al., 2006). In contrast, the typical poor swimming ability (Pakhorukov, 2008) and patchy occurrence (i.e. likely also reflecting a low catchability sensu Alverson, 1971) of H. mediterraneus, along with the high heterogeneous fishing effort applied to deep-water crustacean fisheries, might determine population differentiation at a local scale. ...
Article
The silver roughy, Hoplostethus mediterraneus is a benthopelagic cosmopolitan fish regularly caught as by-catch of the deepwater crustacean trawl fishery (CTF) in the central–eastern Mediterranean. Monthly samples of silver roughy were sampled from the catches of four commercial trawlers in 2004. Each trawler operated in different fishing grounds (FGs), located off Northern Tunisia, South of Sicily, Malta Islands and in South Levant, for which different exploitation levels are reported. The overall length–frequency distribution (LFD) was constructed, and fishing impact indices (length as percentage of LFD, optimum and maximum length, percentage of mega-spawners and total mortality/von Bertalanffy curvature ratio) were calculated. In spite of an overall acceptable status (juveniles, matures and mega-spawners were present in the catch), sampling data revealed significant differences in LFD shape and status indices between FGs. Those FGs traditionally considered more exploited (Northern Tunisia and South of Sicily) showed a dominance of juveniles, a rarefaction of mega-spawners, a reduction in maximum and asymptotic length and a higher Z/K ratio. Considering the general homogeneity of Mediterranean deep-water habitats, the pelagic dispersal of eggs and the poor swimming capabilities of silver roughy, the present results indicated that deep-water trawling may induce a slow and subtle, although significant, erosion of the older, late maturing and slow growing component of the stocks in the Mediterranean (so-called longevity-overfishing).
... Fish assemblages of the investigated seamounts and banks were numerically dominated by two zooplanktivorous fish, A. anthias and C. ruber, frequently observed in dense mixedspecies shoals. A similar structural pattern was described also in other Mediterranean and Atlantic seamounts and deep-sea rocky habitats (Pakhorukov, 2008;Christiansen et al., 2009;Porteiro et al., 2013;Consoli et al., 2016;Consalvo et al., 2021). ...
Article
Fish assemblages inhabiting a complex of south Tyrrhenian seamounts and banks were characterized using a remotely operated vehicle (ROV). Fish distribution was assessed through surveying 15 ROV transects. Video segments of each transect were split into two bathymetric ranges, above and below 200 m depth. In total 28 fish taxa belonging to 22 families were recorded. The number of species observed at the Marettimo Banks and the Aceste Seamount was higher compared with the Tiberio and Scuso Seamounts. The number of species recorded in the shallow part (<200 m depth) of the Marettimo Banks and the Aceste Seamount was higher than in the deeper zone (>200 m). Assemblages were numerically dominated by Anthias anthias , Callanthias ruber and Helicolenus dactylopterus . The occurrence of some elasmobranchs of conservation concern, such as Squatina aculeata , Hexanchus griseus , Squalus blainville and Galeus melastomus , was noteworthy. Differences in fish assemblage composition were observed between the Aceste Seamount and the other sites and especially between the two bathymetric ranges. The fish distribution pattern showed significant relationships with bottom slope and some substrate types. A large occurrence of lost fishing gear characterized the sites closest to the coast (the Marettimo Banks and the Scuso Seamount), providing, along with scanty observations of commercially important fishes, evidence of heavy fishing activities. The adoption of conservation and management actions in the investigated seamounts and banks, such as their inclusion in the Natura 2000 network, would be very helpful to protect some threatened elasmobranchs and restore valuable deep-sea habitats.
... The differences in stomach contents and stable isotope ratios between the benthopelagic fishes at Ampère SMT show a resource partitioning through distinct vertical feeding positions and habitat choice (Fig. 7), as suggested in previous studies at other seamounts (Ehrich, 1974;Pakhorukov, 2008;Hirch and Christiansen, 2010;Nishida et al., 2016). Around the summit plateau of Ampère SMT the predominantly zooplanktivorous and mixed-feeding species showed habitat choices associated with their prey preferences. ...
Article
Specific mechanisms, driving trophic interactions between seamount associated fishes and the pelagic community may be highly variable in different seamount systems. This study investigated the trophic structure and the main prey of benthopelagic fishes from the summit and slope regions of Ampère and Senghor, two shallow seamounts in the subtropical and tropical NE Atlantic, and the adjacent deep-sea plains. For the identification of food sources and nutritional links to the pelagic realm a combination of stomach content and stable isotope ratio (δ¹³C and δ¹⁵N) analyses was used. δ¹³C ranged from −22.2‰ to −15.4‰ and δ¹⁵N covered a total range of 8.0–15.9‰. Feeding types of fish species comprised mainly zooplanktivores and mixed feeders, but also benthivores, piscivores, and predator-scavengers. Based on epipelagic particulate organic matter, they occupied trophic positions between the 2nd and 4th trophic level. Differences in stomach contents and stable isotope signatures indicate a resource partitioning among the benthopelagic fish fauna through distinct habitat choice, vertical feeding positions and prey selection. Topographic trapping of vertically migrating zooplankton on the summit seemed to be of minor importance for food supply of the resident near-bottom fishes, rather horizontal current-driven advection of the planktonic prey was assumed as major factor. Vertically migrating micronekton and mesopelagic fishes show up as key players within the food webs at Ampère and Senghor Seamounts and the adjacent deep-sea plains.
... A number of seamounts extends from the Madeira archipelago (33 • N latitude) to the Portuguese mainland exclusive economic zone (EEZ, 38 • N) defined as the Madeira-Tore geologic complex (Morato et al., 2008). This complex provides appropriate conditions for the occurrence of distinctive and diverse benthic communities (Lobo et al., 2016) and provides spawning locations to bentho-pelagic species, as is the case of T. picturatus (Pakhorukov, 2008;Menezes et al., 2009). The Portuguese coast, that extends along the south-western region of the Iberian Peninsula, includes particular oceanographic and environmental attributes, like the Iberian Poleward Current, the Western Iberia Buoyant Plume, with different processes linked to bathymetry, wind regimes and upwelling filaments (Bettencourt et al., 2004;Santos et al., 2007). ...
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The genetic polymorphism and phenotypic plasticity are key in ecology and evolution. The morphological variability of the contour of fish otoliths has been extensively used for the delimitation of stocks. These studies are conventionally based on average phenotype using elliptic Fourier analysis and lineal discriminant analysis as classifier. Considering new analytical options, such as the wavelet transform and non-parametric algorithms, we here analyzed the otolith shape of Trachurus picturatus from mainland Portugal, Madeira and the Canaries. We explore the phenotypic plasticity throughout a latitudinal gradient, establish a hypothesis to explain this plasticity based on the reaction norms, and determine how the use of average phenotype and/or morphotypes influences in the delimitation of stocks. Four morphotypes were identified in all regions, with an increase of phenotypes in warmer waters. The findings demonstrated that stocks were clearly separated with classification rates over 90%. The use of morphotypes, revealed seasonal variations in their frequencies and per region. The presence of shared phenotypes in different proportions among fishing grounds may open new management approaches in migratory species. These results show the importance of the phenotypic diversity in fisheries management.
... The distance from the bottom was generally less than one body length. In a revision of ROV observations of seamount ichthyofauna from south of the Azores (Pakhorukov, 2008), L. fasciata was included in the near-bottom ichthyocenosis (with other 26 species), a group that remains generally 0.5 m to, more seldom, 1.0 m from the bottom. ...
Article
Many fish species are well-known obligatory inhabitants of shallow-water tropical coral reefs but such associations are difficult to study in deep-water environments. We address the association between two deep-sea fish with low mobility and large sessile invertebrates using a compilation of 20 years of unpublished in situ observations. Data were collected on Northeast Atlantic (NEA) island slopes and seamounts, from the Azores to the Canary Islands, comprising 127 new records of the circalittoral Labridae Lappanella fasciata and 15 of the upper bathyal Ophiididae Benthocometes robustus. Observations by divers, remote operated vehicles (ROV SP, Luso, Victor, Falcon Seaeye), towed vehicles (Greenpeace) and manned submersibles (LULA, Nautile) validated the species association to cold water corals (CWC) and large hydrozoans. L. fasciata occurred from lower infralittoral (41. m) throughout the circalittoral, down to the upper bathyal at 398. m depth. Smaller fishes (< 10. cm) tend to form larger schools up to five individuals, with larger fishes (10-15. cm) occurring alone or in smaller groups at greater depths. The labrids favoured areas with large sessile invertebrates (> 10. cm) occurring at < 1 body-length, swimming inside or in close vicinity to the tallest and most complex three-dimensional structure in the field of observation. These included hydrozoans (Polyplumaria flabellata, Nemertesia antennina), CWC (e.g. Antipathella wollastoni, Acanthogorgia armata, Stichopathes sp.), and less frequently sponges (e.g. Pseudotrachya hystrix). B. robustus presented a coral-cryptic behavior, being recorded in the bathyal zone between 350 and 734. m depth, always inside CWC (e.g. Acanthogorgia spp., Antipathella spp., Callogorgia verticillata, Dendrophyllia alternata, Leiopathes spp.), and remaining within the coral branching. B. robustus were collected with baited traps providing biological information and dietary information reinforcing the trophic linkage between the CWC habitat and this predator. Gathered evidence renders CWC and hydroid gardens as Essential Fish Habitats for both species, being therefore sensitive to environmental and anthropogenic impacts on these Vulnerable Marine Ecosystems. The Mediterranean distribution of L. fasciata is extended to NEA seamounts and island slopes and the amphi-Atlantic distribution of B. robustus is bridged with molecular data support. Both species are expected to occur throughout the Macaronesia and Mediterranean island slopes and shallow seamounts on habitats with large sessile invertebrates.
... The differences in stomach contents and stable isotope ratios be- tween the benthopelagic fishes at Ampère SMT show a resource parti- tioning through distinct vertical feeding positions and habitat choice (Fig. 7), as suggested in previous studies at other seamounts (Ehrich, 1974;Pakhorukov, 2008;Hirch and Christiansen, 2010;Nishida et al., 2016). Around the summit plateau of Ampère SMT the predominantly zooplanktivorous and mixed-feeding species showed habitat choices associated with their prey preferences. ...
Article
Specific mechanisms, driving trophic interactions within the pelagic community may be highly variable in different seamount systems. This study investigated the trophic structure of zooplankton and micronekton above and around Ampère and Senghor, two shallow seamounts in the subtropical and tropical Eastern Atlantic, and over the adjacent abyssal plains. For the identification of food sources and trophic positions stable isotope ratios (δ¹³C and δ¹⁵N) were used. δ¹³C ranged from -24.7‰ to -15.0‰ and δ¹⁵N covered a total range of 0.9-15.9‰. Based on epipelagic particulate organic matter, zooplankton and micronekton usually occupied the 1st-3rd trophic level, including herbivorous, omnivorous and carnivorous taxa. δ¹³C and δ¹⁵N values were generally lower in zooplankton and micronekton of the subtropical waters as compared to the tropical region, due to the differing nutrient availability and phytoplankton communities. Correlations between δ¹³C and δ¹⁵N values of particulate organic matter, zooplankton, micronekton and benthopelagic fishes suggest a linear food chain based on a single energy source from primary production for Ampère Seamount, but no evidence was found for an autochthonus seamount production as compared to the open ocean reference site. Between Senghor Seamount and the open ocean δ¹³C signatures indicate that hydrodynamic effects at seamounts may modify the energy supply at times, but evidence for a seamount effect on the trophic structure of the pelagic communities was weak, which supports the assumption that seamount communities rely to a large extent on advected food sources.
... S. pilchardus is a "winterspawner" in the Canary Islands waters, as at the Portuguese coast, where Santos et al. (2001) found a negative effect of the winter upwelling on S. pilchardus recruitment, and Gamito et al. (2015) linked this with landings. Nevertheless, S. colias and Trachurus spp (C group, the other "winter-spawners" at the Canary Islands) do not seem to be negatively affected by the winter-bloom/upwelling, maybe because they spawn in offshore oceanic waters, that are less influenced by coastal processes such as the winter-upwelling (Pakhorukov, 2008;Santos et al., 2012). ...
Article
The main small pelagic fish species targeted by fishers in the Canary Islands are, in order of importance in landings: the Atlantic chub mackerel Scomber colias, horse mackerels Trachurus spp, the European pilchard Sardina pilchardus and sardinella Sardinella spp. In this study we evaluate seasonal relationships between selected oceanographic variables and these landings. Monthly values of Sea Surface Temperature (SST, °C), SST anomaly (SSTA, °C) and chlorophyll a concentration (Chl-a, mg/m3) were obtained for the study area between January 2009 and December 2016, and compared with the seasonal evolution of a landing index compiled from official sale notes. Non-parametric multivariate analyses enabled assessment of the seasonal variation of the catches over the study period. Despite strong interannual variability, different seasonal patterns were observed for each species, with cooler seasons (lower SST and higher Chl-a) characterized by catches of medium-sized species (S. colias and Trachurus spp), and warmer seasons (higher SST and lower Chl-a) by the smaller-sized species (S. pilchardus and Sardinella spp). SSTA appears to explain the unusual seasonal landings.
... From the analysis of historical references, it can be concluded that Russian vessels operated there during the last decades of the 20th century, employing pelagic and bottom trawling as well as purse seining [11]. Russian effort extended later to other seamounts such as the Josephine and the Ampere [11], targeting aggregating deepsea species as the silver roughy Hoplostethus mediterraneus (Cuvier, 1829) and the common mora Mora mora (Risso, 1810) [12]. At present, the Gorringe Bank is home to a Portuguese longline fishery from vessels based on the mainland, mainly in Peniche fishing port, using bottom longlines for the European conger Conger conger (Linnaeus, 1758), wreckfish Polyprion americanus (Bloch & Schneider, 1801) and pelagic longlines for swordfish Xyphias gladius (Linnaeus, 1758). ...
Article
The activity of the Portuguese fishing fleet operating near seamounts of the Madeira Tore geologic complex was analyzed. The main objective is to identify the different fisheries taking place in the area, characterize the spatial patterns of vessels activity and estimate the fishing intensity, thus contributing to better inform management decisions. Vessel Monitoring System (VMS) and e-logbook data for the period 2012–2014 were used. The combined analysis of these data allowed the identification of fishing events and the estimation of the fishing intensity by gear type, as well as the characterization of general patterns relating to fishing operations. A total of 47 vessels displayed fishing activity in the studied area, mainly longliners based either on the mainland or the Madeira archipelago, visiting different seamounts in fishing trips lasting two to three weeks, and a few pole and line bait boats. Bottom and pelagic longlining alternate throughout the year, the former mostly in spring and summer, targeting the wreckfish Polyprion americanus and the European conger, Conger conger, while the latter is carried out in autumn and winter using a surface longline targeting the swordfish Xiphias gladius and a drifting longline set deeper in the water column, targeting the black scabbard fish Aphanopus carbo. A global evaluation of the fishing intensity and estimation of fishing impact in this area calls for the availability of VMS data, elogbooks and landing declarations from non-Portuguese fleets, making monitoring in these areas a top priority to assess the sustainability of human activities.
... All these authors reported similar to our results that the highest numbers of females were found during the spawning season. Several factors can explain this finding, such as growth variations that affect the vulnerability of juveniles to predation, the ecological behavior of the species (Arkhipov et al., 2002;Menezes et al., 2006;Pakhorukov, 2008), temperature that influences sex determination (Conover and Kynard, 1981). Recruitment or migration patterns may also cause changes in the 1:1 sex ratio and lead to a greater capture of a given sex (Vicentini and Ara ujo, 2003;Amenzoui et al., 2006;Silva, 2007). ...
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This work provides for the first time a description of the reproductive biology of Trachurus picturatus in Portuguese continental waters (between 41° 49′ and 36° 57′ latitude North). From January 2010 to December 2016 a total of 7409 individuals were sampled from bottom trawlers operating on the northwestern coast of Portugal. The observed sex ratio was 0.56 in favor of the females. Monthly variations in gonadosomatic index, proportion of actively spawning individuals, hepatosomatic index and Fulton′s condition factor were analyzed. More than 60% of spawning individuals were recorded in the first quarter, corresponding to the highest values of GSI, and Fulton's K and hepatosomatic index increased after the start of spawning. The morphometric relationships between total length and gutted weight showed significant correlations (high determination coefficient, r² > 0.9) and isometric growth ( b = 3) for both sexes. Results indicate that the spawning season of T. picturatus starts in December and extends until April–May, with a peak in March, which agrees with what has been indicated by other authors for the northeast Atlantic. This work provides important biological information on a species that although not subject to stock assessment is currently the 5th species landed by weight in Portuguese continental waters.
... In the eastern Atlantic, C. coelolepis occurs from Greenland and Iceland to South Africa, although records from western central Africa are scarce (Compagno et al., 1991;Vaz, 2015). Its presence has also been reported in the Mediterranean Sea, the Canary Islands, around the Azores and over the mid-Atlantic Ridge (Barría et al., 2015;Catarino et al., 2015;Hareide et al., 2006;Pakhorukov, 2008;Serena, 2005;Veríssimo et al., 2011). In the western Atlantic it occurs from Canada to Cuba, and from Venezuela to northern Brazil (Bigelow & Schroeder, 1948, 1954. ...
Article
The Portuguese dogfish Centroscymnus coelolepis is a wide‐ranging deep‐water shark and a common by‐catch component of the catches of several mid to deep‐water fisheries. In the present study, two new records from the Southwestern Atlantic Ocean are reported based on specimens caught by bottom‐longline fishing vessels operating in the Argentinean‐Uruguayan Common Fishing Zone. Species identification based on morphology and detailed morphometrics, as well as molecular data are presented for one of the specimens. The distribution of the species over the Southwestern Atlantic is discussed on the basis of available bibliography and a thorough revision of museum collections. The records here presented expands the species' previously acknowledged distribution southwards, from around 21° S to at least 38° S, suggesting it occurs continuously along the shelf break of Eastern South America. However, given the limited access to specimens of deep‐water sharks in the region, the abundance and real extent of C. coelolepis distribution in the Southwestern Atlantic as well as its interaction with deep‐water fisheries remain to be fully assessed. This article is protected by copyright. All rights reserved.
... The distance from the bottom was generally less than one body length. In a revision of ROV observations of seamount ichthyofauna from south of the Azores (Pakhorukov, 2008), L. fasciata was included in the near-bottom ichthyocenosis (with other 26 species), a group that remains generally 0.5 m to, more seldom, 1.0 m from the bottom. ...
... A number of seamounts extends from the Madeira archipelago (33 • N latitude) to the Portuguese mainland exclusive economic zone (EEZ, 38 • N) defined as the Madeira-Tore geologic complex (Morato et al., 2008). This complex provides appropriate conditions for the occurrence of distinctive and diverse benthic communities (Lobo et al., 2016) and provides spawning locations to bentho-pelagic species, as is the case of T. picturatus (Pakhorukov, 2008;Menezes et al., 2009). The Portuguese coast, that extends along the south-western region of the Iberian Peninsula, includes particular oceanographic and environmental attributes, like the Iberian Poleward Current, the Western Iberia Buoyant Plume, with different processes linked to bathymetry, wind regimes and upwelling filaments (Bettencourt et al., 2004;Santos et al., 2007). ...
Article
The identification of fish species using otolith shape has been common in many fields of the marine science. Different analytical processes can be applied for the morphological discrimination, but reviewing the literature we have found conceptual and statistical limitations in the use of shape indices and wavelets (contour analysis), being specially worrying in the first case due to their widespread routine use. In the present study, 42 species were classified using otolith shape indices and wavelets and applying traditional and machine learning classifiers and performance measures (accuracy, Cohen’s kappa statistic, sensitivity and precision). Our results were conclusive, wavelets were a more adequate option for the classification of species than shape indices, independently of classifiers and performance measures considered. The artificial neural network and support vector machine provided the highest values for all performance measures using wavelets. In all cases, the measures of sensitivity and precision pointed out a higher confusion between some otolith patterns using shape indices. Therefore, we strongly discourage the routine use of shape indices for the identification of species.
... Numerical dominance of zooplanktivorous fish, such as A. anthias and C. ruber, has been reported in several studies focused on the fish fauna of seamounts in the Mediterranean and the Atlantic (Pakhorukov, 2008;Christiansen et al., 2009;Porteiro et al., 2013 and references therein;Consoli et al., 2016). ...
Article
Demersal fish assemblages on the rocky bottoms of the Aeolian Archipelago were investigated using a Remotely Operated Vehicle (ROV) within the framework of research activities aimed at drawing up the zoning proposal of a new Italian national marine protected area. Visual assessments were conducted around the seven main islands by means of a total of 36 ROV transects. Video material was divided into 3 parts belonging to 3 Archipelago sectors (Western, Central and Eastern) and into 3 depth ranges (20-50, 51-120, 121-190). Thirty taxa of teleosts (29 species and 1 genus) belonging to 16 families were recorded. The assemblages were numerically dominated by some schooling fishes, such as Anthias anthias, Callanthias ruber and Chromis chromis, which exhibited a depth related partitioning of space, and three non-gregarious species, i.e. Serranus cabrilla, Coris julis and Lappanella fasciata. In terms of species composition, the assemblages observed in the sectors of the Archipelago largely overlapped. No significant sector-related differences were detected in fish species richness, diversity and total density. Species composition and the investigated assemblage parameters were significantly affected by depth. The pattern of variation in species richness among depth ranges changed depending on the archipelago sectors. No significant interaction between the factors depth range and sector was observed for species diversity and total density. Diversity values at 20-50 and 121-190 m depth were similar and significantly higher than that at 51-120 m depth. Fish total density showed a clear decreasing trend with increasing depth, though significant differences were detected between the 20-50 and 51-120 depth layers and the deepest one. Overall, the demersal fish assemblage of the Aeolian Archipelago was poorly diversified and depleted, most likely due to overfishing. This information highlighted the importance of the adoption of specific measures aimed at the recovery of overexploited resources and the restoration of the whole marine ecosystems.
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Macrourids are among the most abundant and diverse demersal fishes in all deep oceans, including the Southwestern Brazilian continental slope. Although not targeted by Brazilian fisheries, they suffer impact similar than the target species, being among the most discarded fishes by deep bottom trawling. Trophic Ecology: Data from research surveys and commercial fishing were used to analyze the trophic ecology of four species inhabiting the upper slope of southern Brazil: Coelorinchus marinii, Malacocephalus occidentalis, M. laevis and Lucigadus ori. For the two abundant ones, ontogenetic changes, seasonal variations, intra- and interspecific dietary overlap, parasite fauna and aspects of functional morphology are also described. C.marinii had an extremely diverse diet, preying infauna, epifauna, plankton, necton and carcasses. M.occidentalis fed on larger and nektonic prey, but also included crabs and carcasses in the diet. Both species showed ontogenetic shifts and seasonal variations in diet composition, both leading to changes in intra- and interspecific diet overlap patterns. Species showed quite distinct feeding anatomy and proportions of body with mouth size, reflecting on feeding strategies. There was little interspecific food overlap. In most cases when the diet was more similar there was a spatial segregation. The coexistence of these species appears to be facilitated by the development of different functional morphologies and feeding strategies. A considerable portion of the diet of these species is due to the consumption of carcasses of pelagic and mesopelagic organisms, and even insects, bypassing the benthic trophic web. Conservative (minimum) estimates of the mean weight of carcasses in diet ranged from 3 to 20%, increasing with the size of the predators and towards deeper waters. C.marinii showed a lower consumption of carcasses and a high proportion of mesopelagic fishes and cephalopods, however, the analysis of the feeding morphology and prey size leads to believe that most of these two groups of prey were consumed as carcasses. This source of food bypass the detritus food chains and connect the concentrations of macrourids to fluctuations in the abundance of epi and mesopelagic organisms and to oceanographic processes that increase their concentration and mortality (e.g. mesoscale anticyclonic eddies). Distribution, Biomass and Oceanography: Data from two seasonal bottom trawl surveys were used to provide information on distribution, abundances, densities, size- composition Malacocephalus occidentalis, M. and biomass estimates for seven species: Coelorinchus marinii, laevis, Lucigadus ori, Hymenocephalus billsam, Ventrifossa macropogon and V. mucocephalus. The total biomass was estimated in 5.5 and 8.3 kt respectively in winter-spring and summer-autumn. C.marinii and M.occidentalis ii comprised 98% of the biomass. For these two abundant species, surface maps were made with spawning areas, feeding index, sex and immature/mature ratios, and were related to oceanographic processes, providing insights on strategies and important processes regulating distribution and abundance patterns. Both species showed a marked seasonal variation in the extent and location of spawning areas. Most C.marinii females were mature (90%), suggesting an early maturation during pelagic phase and acquiring demersal habit just prior the onset of maturation, while M.occidentalis showed few matures females and settle to bottom well before maturity. Temperature rather than depth seems to be the main factor regulating the batimetric distribution of both species. We describe three processes responsible for distribution and abundance patterns found in these species. Different patterns of spatial segregation were found in both species, related with depth, sex and maturity. It is suggested that areas with high biomass Macrouridae (scavengers) are induced by zones of occurrence semi-permanent mesoscale processes (e.g. eddies). These processes increase productivity and enable large biomass of short-lived organisms found in the upper layers, and also increase the concentration, mortality and availability of carcasses, favoring scavenger predators. These processes may be responsible for inconsistencies in biomass of megafauna and macrofauna found in some studies, where biomass of megafauna was of the same order of magnitude or larger than macrofauna, contradicting the Eltonian principle. It is suggested that future studies attempt to relate mesoscale processes with the biomass of potential short-lived prey in surface waters and higher biomass of scavengers. This work highlights the importance of the study of ocean dynamics, combining biological and oceanographic observations, trying to understand the role of mesoscale physical processes on the distribution and abundance patterns of species.
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Macrourids are among the most abundant and diverse demersal fishes in all deep oceans, including the Southwestern Brazilian continental slope. Although not targeted by Brazilian fisheries, they suffer impact similar than the target species, being among the most discarded fishes by deep bottom trawling. Trophic Ecology: Data from research surveys and commercial fishing were used to analyze the trophic ecology of four species inhabiting the upper slope of southern Brazil: Coelorinchus marinii, Malacocephalus occidentalis, M. laevis and Lucigadus ori. For the two abundant ones, ontogenetic changes, seasonal variations, intra- and interspecific dietary overlap, parasite fauna and aspects of functional morphology are also described. C.marinii had an extremely diverse diet, preying infauna, epifauna, plankton, necton and carcasses. M.occidentalis fed on larger and nektonic prey, but also included crabs and carcasses in the diet. Both species showed ontogenetic shifts and seasonal variations in diet composition, both leading to changes in intra- and interspecific diet overlap patterns. Species showed quite distinct feeding anatomy and proportions of body with mouth size, reflecting on feeding strategies. There was little interspecific food overlap. In most cases when the diet was more similar there was a spatial segregation. The coexistence of these species appears to be facilitated by the development of different functional morphologies and feeding strategies. A considerable portion of the diet of these species is due to the consumption of carcasses of pelagic and mesopelagic organisms, and even insects, bypassing the benthic trophic web. Conservative (minimum) estimates of the mean weight of carcasses in diet ranged from 3 to 20%, increasing with the size of the predators and towards deeper waters. C.marinii showed a lower consumption of carcasses and a high proportion of mesopelagic fishes and cephalopods, however, the analysis of the feeding morphology and prey size leads to believe that most of these two groups of prey were consumed as carcasses. This source of food bypass the detritus food chains and connect the concentrations of macrourids to fluctuations in the abundance of epi and mesopelagic organisms and to oceanographic processes that increase their concentration and mortality (e.g. mesoscale anticyclonic eddies). Distribution, Biomass and Oceanography: Data from two seasonal bottom trawl surveys were used to provide information on distribution, abundances, densities, size- composition Malacocephalus occidentalis, M. and biomass estimates for seven species: Coelorinchus marinii, laevis, Lucigadus ori, Hymenocephalus billsam, Ventrifossa macropogon and V. mucocephalus. The total biomass was estimated in 5.5 and 8.3 kt respectively in winter-spring and summer-autumn. C.marinii and M.occidentalis ii comprised 98% of the biomass. For these two abundant species, surface maps were made with spawning areas, feeding index, sex and immature/mature ratios, and were related to oceanographic processes, providing insights on strategies and important processes regulating distribution and abundance patterns. Both species showed a marked seasonal variation in the extent and location of spawning areas. Most C.marinii females were mature (90%), suggesting an early maturation during pelagic phase and acquiring demersal habit just prior the onset of maturation, while M.occidentalis showed few matures females and settle to bottom well before maturity. Temperature rather than depth seems to be the main factor regulating the batimetric distribution of both species. We describe three processes responsible for distribution and abundance patterns found in these species. Different patterns of spatial segregation were found in both species, related with depth, sex and maturity. It is suggested that areas with high biomass Macrouridae (scavengers) are induced by zones of occurrence semi-permanent mesoscale processes (e.g. eddies). These processes increase productivity and enable large biomass of short-lived organisms found in the upper layers, and also increase the concentration, mortality and availability of carcasses, favoring scavenger predators. These processes may be responsible for inconsistencies in biomass of megafauna and macrofauna found in some studies, where biomass of megafauna was of the same order of magnitude or larger than macrofauna, contradicting the Eltonian principle. It is suggested that future studies attempt to relate mesoscale processes with the biomass of potential short-lived prey in surface waters and higher biomass of scavengers. This work highlights the importance of the study of ocean dynamics, combining biological and oceanographic observations, trying to understand the role of mesoscale physical processes on the distribution and abundance patterns of species.
Article
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Biological aspects of sailfin dory, Zenopsis conchifer, were studied from 839 individuals obtained from deep-sea commercial bottom trawling off southern Brazil at depths up to 526 m in 2002 and 2003. Samples included fish from 101 mm Lt and 15 g up to 640 mm Lt and 2,9 g. The sex-ratio was 50% at 150 mm Lt and between 300–350 mm Lt, with females outnumbering males in the remaining size classes. Reproductive activity seems to peak between July and August (austral winter). Size at attainment of 50% maturity (Lt50) was 311 mm Lt in females. The mean length and maturity of the specimens increased with depth, suggesting that larger fish concentrate in deeper waters.
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This work aims at characterising the seamount physiography and biology in the OSPAR Convention limits (North-East Atlantic Ocean) and Mediterranean Sea. We first inferred potential abundance, location and morphological characteristics of seamounts, and secondly, summarized the existing biological, geological and oceanographic in-situ re-5 search, identifying examples of well-studied seamounts. Our study showed that the seamount population in the OSPAR area (North-East Atlantic) and in Mediterranean Sea is large with around 1061 and 202 seamount-like features, respectively. Similarly, seamounts occupy large areas of about 1 116 000 km 2 in the OSPAR region and of about 184 000 km 2 in the Mediterranean Sea, which is much larger than previously 10 thought. The presence of seamounts in the North-East Atlantic has been known since the late 19th Century but overall knowledge regarding seamount ecology and geology is still relatively poor. Only 37 seamounts in the OSPAR area (3.5 % of all seamounts in the region), 22 in the Mediterranean Sea (9.2 % of all seamounts in the region) and 25 in the North-East Atlantic south of the OSPAR have in-situ information. Seamounts 15 mapped in both areas are in general very heterogeneous, showing diverse geophysical characteristics. These differences will likely affect the biological diversity and produc-tion of resident and associated organisms.
Article
Benthopelagic fishes were sampled during three cruises to Seine Seamount, NE Atlantic, using bottom trawls and an epibenthic sledge. A total of 16 fish species were caught on the summit plateau of the seamount at 160–180 m depth, belonging to 15 different families. Four species were common to all types of trawls, whereas the other species were found only in part of the catches. Most fish caught were small species and typical for shelf and seamount communities. The most abundant fish was the snipefish, Macroramphosus spp., which was important also in terms of biomass. The population structure (size classes and length/weight relationships) of the five most abundant species (Macroramphosus spp., Capros aper, Anthias anthias, Callanthias ruber and Centracanthus cirrus) shows that usually two or three size classes, probably representing age groups (year classes), were present, and that growth rates were high. A stomach content analysis of these fishes revealed a predominance of pelagic prey, mainly small copepods. No indications for a seamount effect in terms of enhanced biomass or topographic blockage were found.
Fish from Nazca and Sala y Gómez Ridges
  • N V Parin
  • G A Golovan
  • N P Pakhorukov
N. V. Parin, G. A. Golovan', N. P. Pakhorukov, et al., " Fish from Nazca and Sala y Gómez Ridges (Based on Materials of the Cruise of R/V Ikhtiandr), " in Fish of the Open Ocean (IOAN SSSR, Moscow, 1980), pp. 5–18.
per an hour of trawling
  • Pshenichnyi
per an hour of trawling (Pshenichnyi et al., 1986;
Large individuals stayed at the light and shady boundary, and small fish allowed the device to approach them at a distance of 3–4 m and then rapidly at a rate of up to 2 m/s left the zone of visibility of an observer
  • Shcherbachev
0 m from the ground, preferring sites with a bro-ken bottom configuration. Large individuals stayed at the light and shady boundary, and small fish allowed the device to approach them at a distance of 3–4 m and then rapidly at a rate of up to 2 m/s left the zone of visibility of an observer. They occurred in trawl catches on Hyéres, Plato, Atlantis, and Ampere seamounts, the depth of 460–900 m (Ehrich, 1977; Shcherbachev et al., 1985; our data). In the area of banks of the Azores archipelago, the species periodically forms large com-mercial aggregations where its catches comprise 30–40 t
Visual Observations of Distribution and Behavior of Fish from the Kyüsyü-Palau Ridge
  • G A Golovan
  • N P Pakhorukov
  • Yu V Chmovzh
G. A. Golovan', N. P. Pakhorukov, and Yu. V. Chmovzh, " Visual Observations of Distribution and Behavior of Fish from the Kyüsyü-Palau Ridge, " in Underwater Studies for Biooceanological and Fish Management Purposes (VNIRO, Moscow, 1989), pp. 96–103.
Distribution and Behavior of Deepwater Fish in the Region of the Kuril Islands
  • G A Golovan
  • N P Pakhorukov
  • V N Sysa
G. A. Golovan', N. P. Pakhorukov, and V. N. Sysa, " Dis-tribution and Behavior of Deepwater Fish in the Region of the Kuril Islands, " Biol. Morya, No. 1, 70–72 (1990).
Myctophidae of the World Ocean
  • V E Bekker
Observations of the Behavior of Wreckfish Polyprion amerisanus (Schneider) (Serranidae),” Vopr
  • A A Glukhov
  • M P Zaferman
  • A. A. Glukhov
Bericiformes of the World Ocean
  • A N Kotlyar
Family Myctophidae. Fishes of the Western North Atlantic
  • B G Nafpaktites
  • R H Backus
  • J E Gradoch
Ichthyofauna of Seamounts of Boreal and Subtropical Zones of the Northern Atlantic
  • E I Kukuev
  • E. I. Kukuev
Visual Observations of the Fish of the Error Seamount in the Western Tropical Part of the Indian Ocean
  • N P Pakhorukov
  • O N Danilyuk
  • N. P. Pakhorukov
Mesobenthal and Mesobenthopelagic Fish of Some Seamounts in the Western Tropical Part of the Indian Ocean
  • N Yu
  • N V Shcherbachev
  • N P Parin
  • A S Pakhorukov
  • Piatrovskii
A Preliminary Review of Ichthyofauna of Nazca and Sala y Gomez Ridges
  • N V Parin
  • N. V. Parin
Biotopic Classification of Bottom-Associated Fishes Inhabiting the Thalassic Epimesobenthic Zone of the World Ocean (Based on Visual Observations from Manned Submersibles
  • N V Parin
  • N P Pakhorukov
  • N. V. Parin
Bottom and Near-Bottom Fish of the Rio Grande Plateau (the southwestern part of the Atlantic Ocean
  • N V Parin
  • Yu N Shcherbachev
  • N P Pakhorukov
  • N. V. Parin
Fish Resources of the Talassobathyal of the Atlantic Ocean
  • B N Pshenichnyi
  • A N Kotlyar
  • A A Glukhov
  • B. N. Pshenichnyi
On the Structure of the Population of Oceanic Mackerel Trachurus picturatus picturatus (Bodwich
  • I E Shaboneev
  • E I Ryazantsev
  • I. E. Shaboneev
Composition of Bottom and Near-Bottom Ichthyocenoses of Seamounts of the Southern Part of the North Atlantic Ridge
  • N Yu
  • E I Shcherbachev
  • V I Kukuev
  • Shlibanov
Die Fishfauna der Grosen Meteor Bank
  • S Ehrich
Behavior and Distribution of Bottom and Near-Bottom Fish on the Emperor Seamount Chain (the Pacific Ocean
  • N P Pakhorukov
  • N. P. Pakhorukov
Commercial Ichthyofauna of Seamounts of the World Ocean
  • N V Parin
  • N P Pakhorukov
Deepwater Near-Bottom Fish from the Walvis Seamount and Adjacent Regions
  • N P Pakhorukov
  • N. P. Pakhorukov
Distribution and Behavior of the Bottom and Demersal Fish of the Rio Grande Plateau (the Atlantic Ocean
  • N P Pakhorukov
  • N. P. Pakhorukov
Underwater Observations on Deepwater Fish of the Atlantic Ocean in the Region of the Sierra Leone Rise
  • N P Pakhorukov
  • N. P. Pakhorukov
Distribution and Behavior of Fish on Banks of the Southern-Azores Region
  • N P Pakhorukov
  • N. P. Pakhorukov
Composition of Bottom and Near-Bottom Ichthyocenoses of Seamounts of the Southern Part of the North Atlantic Ridge
  • Yu N Shcherbachev
  • E I Kukuev
  • V I Shlibanov
  • Yu. N. Shcherbachev
Fish from Nazca and Sala y Gómez Ridges (Based on Materials of the Cruise of R/V Ikhtiandr
  • N V Parin
  • G A Golovan
  • N P Pakhorukov
  • N. V. Parin
Mesobenthal and Mesobenthopelagic Fish of Some Seamounts in the Western Tropical Part of the Indian Ocean
  • Yu N Shcherbachev
  • N V Parin
  • N P Pakhorukov
  • A S Piatrovskii
  • Yu. N. Shcherbachev