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Yves Cherel - One of the best experts on this subject based on the ideXlab platform.
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Stomach contents of long-finned pilot whales, Globicephala melas mass-stranded in Tasmania.
PLOS ONE, 2019Co-Authors: Isabel Beasley, Yves Cherel, Susan Robinson, Emma Betty, Rie Hagihara, Rosemary GalesAbstract:New data are reported from analyses of stomach contents from 114 long-finned pilot whales mass-stranded at four locations around Tasmania, Australia from 1992-2006. Identifiable prey remains were recovered from 84 (74%) individuals, with 30 (26%) individuals (17 females and 13 males) having empty stomachs. Prey remains comprised 966 identifiable lower beaks and 1244 upper beaks, belonging to 17 families (26 species) of cephalopods. Ommastrephidae spp. were the most important cephalopod prey accounting for 16.9% by number and 45.6% by reconstructed mass. Lycoteuthis lorigera was the next most important, followed by Ancistrocheirus lesueurii. Multivariate statistics identified significant differences in diet among the four stranding locations. Long-finned pilot whales foraging off Southern Australia appear to be targeting a diverse assemblage of prey (>= 10 species dominated by cephalopods). This is compared to other similar studies from New Zealand and some locations in the Northern Hemisphere, where the diet has been reported to be primarily restricted to
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Eastern rockhopper penguins Eudyptes filholi as biological samplers of juvenile and sub-adult cephalopods around Campbell Island, New Zealand
Polar Biology, 2018Co-Authors: J. C. Xavier, Filipe R. Ceia, Yves Cherel, J. P. Queirós, B. Guimarães, R. Rosa, D. M. Cunningham, P. J. Moors, D. R. ThompsonAbstract:Early life-history stages of cephalopods are known to play an important role as prey in food webs of the Southern Ocean, but little information is available about their biology and availability to predators. Top predators, such as penguins, are known to feed regularly on coastal juvenile/sub-adult cephalopods. Using eastern rockhopper penguins Eudyptes filholi as coastal biological samplers, we examined in detail the cephalopod component of their diet in Campbell Island (New Zealand) during two consecutive breeding seasons in order to evaluate (1) the relative importance of cephalopods (by frequency of occurrence, by number and by mass) to the diet of both adult and chick penguins, (2) the habitat and trophic levels of the cephalopods in the region and (3) the status of the juvenile/sub-adult cephalopod community in the waters around Campbell Island. Our results show that eastern rockhopper penguins feed on eight species of juvenile and sub-adult cephalopods, with Onykia ingens , Martialia hyadesi and Octopus campbelli being the most important species by frequency of occurrence, number and mass. Differences between the diets of adult and chick penguins and between breeding seasons were found. Habitat ( δ ^13C) and trophic level ( δ ^15N) information also showed that all cephalopod species (and all studied stages) occupy similar habitat on the Campbell shelf, with M. hyadesi showing lower δ ^15N values than O. ingens and O. campbelli . This study indicates that eastern rockhopper penguins can be valuable biological samplers of local juvenile/sub-adult cephalopods (including poorly known cephalopod species) around Campbell Island when breeding, that these cephalopods were likely to be caught naturally (not from fisheries), providing relevant information for the conservation of these penguins.
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A review on the biodiversity, distribution and trophic role of cephalopods in the Arctic and Antarctic marine ecosystems under a changing ocean
Marine Biology, 2018Co-Authors: José C. Xavier, Yves Cherel, Rui Rosa, Louise Allcock, Rushan M. Sabirov, Martin E. Blicher, Alexey V. GolikovAbstract:Cephalopods play an important role in polar marine ecosystems. In this review, we compare the biodiversity, distribution and trophic role of cephalopods in the Arctic and in the Antarctic. Thirty-two species have been reported from the Arctic, 62 if the Pacific Subarctic is included, with only two species distributed across both these Arctic areas. In comparison, 54 species are known from the Antarctic. These polar regions share 15 families and 13 genera of cephalopods, with the giant squid Architeuthis dux the only species confirmed to occur in both the Arctic and Antarctic. Polar cephalopods prey on crustaceans, fish, and other cephalopods (including cannibalism), whereas predators include fish, other cephalopods, seabirds, seals and whales. In terms of differences between the cephalopod predators in the polar regions, more Antarctic seabird species feed on cephalopods than Arctic seabirds species, whereas more Arctic mammal species feed on cephalopods than Antarctic mammal species. Cephalopods from these regions are likely to be more influenced by climate change than those from the rest of the World: Arctic fauna is more subjected to increasing temperatures per se, with these changes leading to increased species ranges and probably abundance. Antarctic species are likely to be influenced by changes in (1) mesoscale oceanography (2) the position of oceanic fronts (3) sea ice extent, and (4) ocean acidification. Polar cephalopods may have the capacity to adapt to changes in their environment, but more studies are required on taxonomy, distribution, ocean acidification and ecology.
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the cephalopod prey of the weddell seal leptonychotes weddellii a biological sampler of the antarctic marine ecosystem
Polar Biology, 2016Co-Authors: Agustina Negri, A. Corbalán, G A Daneri, Filipe R. Ceia, Nestor Coria, Rui P. Vieira, Yves Cherel, José C. XavierAbstract:Weddell seals, Leptonychotes weddellii, are important apex predators in the food web of the Antarctic marine ecosystem. However, detailed information on their trophic relationships with cephalopods is scarce. Moreover, cephalopods play a key role in the marine environment, but knowledge of their feeding habits is limited by lack of data. Here, we have combined the use of this seal as a biological sampler together with measurements of the stable isotopic signature of the beaks of their cephalopod prey. Thus, the aims of the present study were: (1) to examine in detail the cephalopod portion of the diet of Weddell seals by means of scat analysis and (2) to assess the habitat use and trophic level of the different cephalopod prey taxa identified. From January to February 2009, a total of 48 faecal droppings were collected at Hope Bay, Antarctic Peninsula. Cephalopods were mainly represented by beaks (n = 83) which were identified to the lowest possible taxonomic level. Furthermore, subsamples of beaks were separated for further isotopic analysis. Relative abundance of stable isotopes of carbon (δ13C) and nitrogen (δ15N) was determined by continuous-flow isotope-ratio mass spectrometry. Cephalopods were represented uniquely by octopods of the subfamily Eledoninae. Pareledone turqueti was the dominant prey species followed by the papillated Pareledone species group and Adelieledone polymorpha. We conclude that Weddell seals preyed primarily on benthic prey resources. Furthermore, the relatively similar δ13C and δ15N values in beaks of the three octopod prey taxa suggest that these share the same type of habitat and occupy similar trophic level positions.
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Habitat and trophic ecology of Southern Ocean cephalopods from stable isotope analyses
Marine Ecology Progress Series, 2015Co-Authors: Miguel Guerreiro, Filipe R. Ceia, Yves Cherel, Richard A. Phillips, Pedro Alvito, Rui Rosa, José C. XavierAbstract:Although cephalopods play a critical role in marine food webs both as predators and prey, there is a limited knowledge of several basic aspects of their ecology, including their habitat and trophic level, in the Southern Ocean. We examined the ecological role of several Southern Ocean cephalopod species by analyzing δ13C and δ15N values in lower cephalopod beaks obtained from diet samples of wandering albatross Diomedea exulans from South Georgia (Atlantic Ocean), and from Crozet and Kerguelen Islands (Indian Ocean). Beak δ13C values ranged from −25.7 to −17.9‰, and were used to assign different cephalopod species to the subtropical, sub- Antarctic or Antarctic Zones. Beak δ15N values were more variable among species, ranging from 2.4 to 13.3‰, a difference of ~11‰ that represents approx. 3 trophic levels. Differences among islands in isotope ratios in the same cephalopod species (higher δ15N and lower δ13C values in South Georgia) were attributed to regional oceanographic processes. Antarctic cephalopods occupy niches similar to those found in some pelagic fish, seabirds and marine mammals. As cephalopods are key components in Southern Ocean food webs, these results greatly advance our understanding of the structure, energy and carbon flows in this polar ecosystem.
José C. Xavier - One of the best experts on this subject based on the ideXlab platform.
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A review on the biodiversity, distribution and trophic role of cephalopods in the Arctic and Antarctic marine ecosystems under a changing ocean
Marine Biology, 2018Co-Authors: José C. Xavier, Yves Cherel, Rui Rosa, Louise Allcock, Rushan M. Sabirov, Martin E. Blicher, Alexey V. GolikovAbstract:Cephalopods play an important role in polar marine ecosystems. In this review, we compare the biodiversity, distribution and trophic role of cephalopods in the Arctic and in the Antarctic. Thirty-two species have been reported from the Arctic, 62 if the Pacific Subarctic is included, with only two species distributed across both these Arctic areas. In comparison, 54 species are known from the Antarctic. These polar regions share 15 families and 13 genera of cephalopods, with the giant squid Architeuthis dux the only species confirmed to occur in both the Arctic and Antarctic. Polar cephalopods prey on crustaceans, fish, and other cephalopods (including cannibalism), whereas predators include fish, other cephalopods, seabirds, seals and whales. In terms of differences between the cephalopod predators in the polar regions, more Antarctic seabird species feed on cephalopods than Arctic seabirds species, whereas more Arctic mammal species feed on cephalopods than Antarctic mammal species. Cephalopods from these regions are likely to be more influenced by climate change than those from the rest of the World: Arctic fauna is more subjected to increasing temperatures per se, with these changes leading to increased species ranges and probably abundance. Antarctic species are likely to be influenced by changes in (1) mesoscale oceanography (2) the position of oceanic fronts (3) sea ice extent, and (4) ocean acidification. Polar cephalopods may have the capacity to adapt to changes in their environment, but more studies are required on taxonomy, distribution, ocean acidification and ecology.
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the cephalopod prey of the weddell seal leptonychotes weddellii a biological sampler of the antarctic marine ecosystem
Polar Biology, 2016Co-Authors: Agustina Negri, A. Corbalán, G A Daneri, Filipe R. Ceia, Nestor Coria, Rui P. Vieira, Yves Cherel, José C. XavierAbstract:Weddell seals, Leptonychotes weddellii, are important apex predators in the food web of the Antarctic marine ecosystem. However, detailed information on their trophic relationships with cephalopods is scarce. Moreover, cephalopods play a key role in the marine environment, but knowledge of their feeding habits is limited by lack of data. Here, we have combined the use of this seal as a biological sampler together with measurements of the stable isotopic signature of the beaks of their cephalopod prey. Thus, the aims of the present study were: (1) to examine in detail the cephalopod portion of the diet of Weddell seals by means of scat analysis and (2) to assess the habitat use and trophic level of the different cephalopod prey taxa identified. From January to February 2009, a total of 48 faecal droppings were collected at Hope Bay, Antarctic Peninsula. Cephalopods were mainly represented by beaks (n = 83) which were identified to the lowest possible taxonomic level. Furthermore, subsamples of beaks were separated for further isotopic analysis. Relative abundance of stable isotopes of carbon (δ13C) and nitrogen (δ15N) was determined by continuous-flow isotope-ratio mass spectrometry. Cephalopods were represented uniquely by octopods of the subfamily Eledoninae. Pareledone turqueti was the dominant prey species followed by the papillated Pareledone species group and Adelieledone polymorpha. We conclude that Weddell seals preyed primarily on benthic prey resources. Furthermore, the relatively similar δ13C and δ15N values in beaks of the three octopod prey taxa suggest that these share the same type of habitat and occupy similar trophic level positions.
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Habitat and trophic ecology of Southern Ocean cephalopods from stable isotope analyses
Marine Ecology Progress Series, 2015Co-Authors: Miguel Guerreiro, Filipe R. Ceia, Yves Cherel, Richard A. Phillips, Pedro Alvito, Rui Rosa, José C. XavierAbstract:Although cephalopods play a critical role in marine food webs both as predators and prey, there is a limited knowledge of several basic aspects of their ecology, including their habitat and trophic level, in the Southern Ocean. We examined the ecological role of several Southern Ocean cephalopod species by analyzing δ13C and δ15N values in lower cephalopod beaks obtained from diet samples of wandering albatross Diomedea exulans from South Georgia (Atlantic Ocean), and from Crozet and Kerguelen Islands (Indian Ocean). Beak δ13C values ranged from −25.7 to −17.9‰, and were used to assign different cephalopod species to the subtropical, sub- Antarctic or Antarctic Zones. Beak δ15N values were more variable among species, ranging from 2.4 to 13.3‰, a difference of ~11‰ that represents approx. 3 trophic levels. Differences among islands in isotope ratios in the same cephalopod species (higher δ15N and lower δ13C values in South Georgia) were attributed to regional oceanographic processes. Antarctic cephalopods occupy niches similar to those found in some pelagic fish, seabirds and marine mammals. As cephalopods are key components in Southern Ocean food webs, these results greatly advance our understanding of the structure, energy and carbon flows in this polar ecosystem.
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Cephalopod fauna of South Pacific waters: new information from breeding New Zealand wandering albatrosses
Marine Ecology Progress Series, 2014Co-Authors: José C. Xavier, Yves Cherel, Kath Walker, Graeme Elliott, David ThompsonAbstract:Cephalopods play an important ecological role in the Southern Ocean, being the main prey group of numerous top predators. However, their basic ecology and biogeography is still poorly known, particularly in the lightly sampled Pacific sector of the Southern Ocean. We collected and analysed information on cephalopods in that area, using Antipodean and Gibson’s wandering albatrosses (Diomedea antipodensis antipodensis and D. antipodensis gibsoni, respectively) breeding at Antipodes Islands and Auckland Islands, respectively, in the New Zealand subantarctic islands as samplers, as they are known from tracking studies to cover huge areas of the Pacific sector of the Southern Ocean (Antipodean wandering albatrosses mostly forage east of New Zealand, whereas Gibson’s wandering albatrosses forage west of New Zealand). A total of 9111 cephalopod beaks, from 41 cephalopod taxa, were identified from boluses (voluntarily regurgitated items by chicks). The families Histioteuthidae (e.g. Histioteuthis atlantica) and Onychoteuthidae (e.g. Moroteuthis robsoni) were the most important cephalopods numerically and by reconstructed mass, respectively, in both wandering albatross species. Combining this information with previously gathered data on cephalopods in the Atlantic and Indian sectors of the Southern Ocean, we provide evidence from predators of the circumpolar distribution of numerous key cephalopod species in the Southern Ocean, and provide new information on poorly known cephalopods (i.e. relevance in the diet of wandering albatrosses, sizes consumed, biodiversity in the South Pacific, assemblages according to predator breeding sites) in one of the most remote ocean areas in the planet.
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Cephalopods in marine predator diet assessments: why identifying upper and lower beaks is important
ICES Journal of Marine Science, 2011Co-Authors: José C. Xavier, Richard A. Phillips, Yves CherelAbstract:Cephalopods are components of the diet of many predators worldwide. They are identified mainly using their chitinized upper and lower beaks, but because it has been assumed that the number of upper and lower beaks would be the same in predator diet samples, more effort has been put into creating keys for the lower beaks, which are more easily identifiable from morphology. A test is made of whether the number of upper and lower beaks differs in diet samples collected from a major cephalopod predator, the wandering albatross (Diomedea exulans), potential biases in the estimation of predator diets are assessed, and upper: lower beak ratios in published studies of other seabirds, seals, whales, and fish from different parts of the world reviewed. The ratio of upper to lower beaks in diet samples from wandering albatrosses varied greatly in a single year (from 69.6% more lower beaks to 59% more upper beaks), and between years (from 0.5 to 32.1% more upper beaks), and biases were greater for certain cephalopod species, resulting in underestimation of their relative importance. Future studies need to consider using both upper and lower beaks to improve the assessment of the contribution of different cephalopods to predator diets.
P L Pascoe - One of the best experts on this subject based on the ideXlab platform.
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the diet of sperm whales physeter macrocephalus linnaeus 1758 off the azores
Philosophical Transactions of the Royal Society B, 1993Co-Authors: M. R. Clarke, Helen R Martins, P L PascoeAbstract:Stomach contents from 17 sperm whales, 15 males and two females, caught during commercial activities in 1981-1984 in the Azores region were identified and measured. A total of 28 738 cephalopods and 16 fish were represented in the collections. In addition, there were tunicates in two whales and man-made products in three whales. None of the stomachs were empty. Flesh was present in 94.1% and indigestible fragments alone, including mandibles (beaks) of cephalopods, were present in 5.9% of the stomachs. Twelve species of cephalopod were represented by flesh and 40 species were represented by lower beaks. The cephalopod families contributing food to the whales in this region are, in order of their contribution by estimated mass, the Octopoteuthidae (39.8%), the Histioteuthidae (32.7%), the Architeuthidae (12.1%), the Lepidoteuthidae (4.5%), the Ommastrephidae (3.4%), the Pholidoteuthidae (2.1%), the Cycloteuthidae (1.9%), the Cranchiidae (1.7%) and eight other families each contributing less than 1% by mass. Presence of Gonatus beaks in the stomachs show which whales have migrated southwards to the Azores just prior to capture and the presence of a large Megalocranchia species possibly shows which whales have migrated from higher latitudes off Iceland. However, the presence of Teuthowenia maculata shows which whales came north from the West coast of Africa, just prior to capture. The modal mass of cephalopods consumed is 400-450 g which represents 0.00001 of the whales' body mass. 77.5% of the species eaten have luminous organs and 82% of the species are neutrally buoyant. It seems likely that the sperm whale is obtaining 77% of its food by swimming through luminous shoals of slow-swimming, neutrally bouyant squids and only about 23% by chasing faster swimming, larger cephalopods. Cephalopods not previously recorded from the North Atlantic are Onychoteuthis borealijaponicus, and Histioteuthis bonnellii corpuscula. Histioteuthis?miranda may have been collected by the whales much further south than the Azores. Species not recorded previously in the diet of sperm whales in the North Atlantic are Ommastrephes bartrami, Gonatus steenstrupi, Histioteuthis?miranda, H. bonnellii corpuscula, H. meleagroteuthis, Discoteuthis laciniosa, Mastigoteuthis species, Chiroteuthis species,?Helicocranchia, Liocranchia reinhardti, and?Liguriella.
Michele K. Nishiguchi - One of the best experts on this subject based on the ideXlab platform.
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A combined approach to the phylogeny of Cephalopoda (Mollusca)
Cladistics, 2004Co-Authors: Annie R. Lindgren, Gonzalo Giribet, Michele K. NishiguchiAbstract:Cephalopoda represents a highly diverse group of molluscs, ranging in habitat from coastal regions to deep benthic waters. While cephalopods remain at the forefront of modern biology, in providing insight into fields such as neurobiology and population genetics, little is known about the relationships within the group. This study provides a comprehensive phylogenetic analysis of Cephalopoda (Mollusca) using a combination of molecular and morphological data. Four loci (three nuclear 18S rRNA, fragments of 28S rRNA and histone H3 and one mitochondrial cytochrome c oxidase subunit I) were combined with 101 morphological characters to test the relationships of 60 species of cephalopods, with emphasis within Decabrachia (squids and cuttlefishes). Individual and combined data sets were analyzed using the direct optimization method, with parsimony as the optimality criterion. Analyses were repeated for 12 different parameter sets accounting for a range of indel ⁄ change and transversion ⁄ transition cost ratios. Most analyses support the monophyly of Cephalopoda, Nautiloidea, Coleoidea and Decabrachia, however, the monophyly of Octobrachia was refuted due to the lack of support for a Cirroctopoda + Octopoda group. When analyzing all molecular evidence in combination and for total evidence analyses, Vampyromorpha formed the sister group to Decabrachia under the majority of parameters, while morphological data and some individual data sets supported a sister relationship between Vampyromorpha and Octobrachia. Within Decabrachia, a relationship between the sepioids Idiosepiida, Sepiida, Sepiolida and the teuthid Loliginidae was supported. Spirulida fell within the teuthid group in most analyses, further rendering Teuthida paraphyletic. Relationships within Decabrachia and specifically Oegopsida were found to be highly parameter-dependent. � The Willi Hennig Society 2004.
Uwe Piatkowski - One of the best experts on this subject based on the ideXlab platform.
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influence of temperature and salinity on the trace element incorporation into statoliths of the common cuttlefish sepia officinalis
Marine Biology, 2007Co-Authors: Karsten Zumholz, Uwe Piatkowski, A Thor E H Hansteen, Peter CrootAbstract:The use of statolith chemistry to trace migration pathways and distinguish populations of cephalopods is based on the assumption that the elemental composition of statoliths is influenced by physicochemical properties of the ambient environment. However, such influences have not been investigated experimentally up until now. This study presents the first microchemical analyses of cephalopod statoliths obtained from laboratory experiments under different controlled temperature and salinity conditions. Our results show that statolith chemical composition is strongly related to both salinity and temperature in ambient waters. The Ba/Ca ratio is negatively related to temperature and shows no relation to salinity. The I/Ca ratio is positively related to temperature and negatively to salinity. No Sr/Ca relation was found to either salinity or temperature, suggesting that the well-established proxy strontium is not as useful in cephalopod statoliths as in other biomineralized aragonites. Microanalysis of trace elements, however, shows an enormous potential for field studies on distribution, migration and stock separation of cephalopods. Furthermore, Synchrotron X-ray Fluorescence Analysis is introduced as a promising novel method for statolith analysis, providing a spatial resolution of typically 10–15 μm combined with detection limits down to 0.5 ppm.
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stomach contents of a northern bottlenose whale hyperoodon ampullatus stranded at hiddensee baltic sea
Journal of the Marine Biological Association of the United Kingdom, 1998Co-Authors: R. Lick, Uwe PiatkowskiAbstract:The stomach of a female northern bottlenose whale, Hyperoodon ampullatus (Odontoceti: Ziphiidae) stranded at Hiddensee Island, western Baltic Sea, on 23 August 1993 contained 7465 cephalopod beaks (4934 upper and 2531 lower). The lower beaks were identified, their rostrallengths were measured and used to estimate size and mass of the cephalopods consumed by the whale. Alllower beaks belonged to one species, the boreoatlantic gonate squid Gonatus fabricii (Cephalopoda: Teuthoidea) indicating a mean squid mantle length of 21·9 cm and a mean squid wet mass of 220·7 g. The total squid biomass in the whale's stomach represented by the lower beaks was 598·6 kg. Assuming that all upper beaks belong to G. fabricii, the squid biomass taken by the whale was estimated to be 1089 kg. Besides the beaks partly digested squid gladii, spermatophores and 15 specimens of the fish parasite Sphyrion lumpi (Crustacea: Copepoda) occurred in the stomach. No fish remains were found.
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On the distribution of pelagic cephalopods in the Arabian Sea
Bulletin of Marine Science, 1991Co-Authors: Uwe Piatkowski, Wolfgang WelschAbstract:From April to June of 1987 R/V Meteor collected zooplankton and micronekton samples in the northeastern part of the Arabian Sea. One hundred and fifty-seven cephalopod specimens were captured by oblique IKMT hauls through water depths from 1,000 to 0 m and identified to the lowest possible taxon. Thirteen species of nine families were recorded. The majority of the specimens were early life stages of pelagic oceanic species. The cranchiid squid Liocranchia reinhardti was the dominant form (108 specimens) followed by the enoploteuthid squids Abraliopsis lineata (22) and Abralia marisarabica (9). Size-frequency compositions and maps of the geographical distribution are compiled for the most abundant species. The data reveal a tropical cephalopod fauna and will improve the poor knowledge on the distribution patterns of pelagic cephalopods in the Indian Ocean.