Lepidonotothen Squamifrons Research Articles

Population dynamics and spatial structure of the grey rockcod (Lepidonotothen squamifrons) in the vicinity of Heard Island and the McDonald Islands.

The grey rockcod, Lepidonotothen squamifrons is an important prey species for seals, penguins and Patagonian toothfish (Dissostichus eleginoides) in the Southern Ocean. Across the Kerguelen Plateau, the species was fished to commercial extinction (ca. 152 000 tonnes between 1971 and 1978) prior to the declaration of the French Exclusive Economic Zone in 1979 and the Australian Fishing Zone in 1981. In this study we estimate; age, growth, maturity, sex ratio, body condition (weight-at-length), and population density of grey rockcod using data from 19 trawl surveys from 1990 to 2014. There appeared to be three distinct geographical populations, with differences in biological parameters within each population. This study has identified separate metapopulations within the southern region of the Kerguelen Plateau and we recommend that management should take into account the different characteristics of these populations, and that this meta-population structure may be a factor in why this species required several decades to show signs of recovery.

Species identification and population genetics of the Antarctic fish genera Lepidonotothen and Nototheniops (Perciformes, Notothenioidei)

AbstractAccurate species identification is essential to assess biodiversity and species richness in ecosystems threatened by rapid and recent environmental changes, such as warming in most Antarctic waters. The Lepidonotothen species complex comprises demersal notothenioid fishes which inhabit the shelf areas of the Antarctic Peninsula, the Scotia Arc and sub‐Antarctic islands with a circum‐Antarctic distribution. Species determination in this group has often been problematic. In particular, whether Lepidonotothen squamifrons and Lepidonotothen kempi are valid as separate species has been questioned. In this study, we analysed the genetic variation among four nominal southern polar species within this complex (L. kempi, L. squamifrons, Nototheniops larseni, Nototheniops nudifrons) by means of three different markers (ND2 and tRNA mitochondrial genes and a panel of 16 nuclear microsatellites). We tested whether individuals morphologically assigned to L. kempi showed genetic separation from L. squamifrons. Our analyses indicated a lack of differentiation between L. kempi and L. squamifrons. However, a genetically distinct population was found for L. squamifrons at the Shag Rocks islands near South Georgia. Antarctic and sub‐Antarctic islands are known to be home to many cryptic species and further studies will elucidate if the genetically differentiated population we found potentially originated from this context and can be considered an incipient species. Our analysis contributes to further characterize the species composition of the most abundant fish suborder in the Southern Ocean, which is among the regions most threatened by climate change.

First record of gray rockcod Lepidonotothen squamifrons larvae in the Amundsen Sea, Antarctic: implication for a new spawning ground and early life characteristics

First record of gray rockcod Lepidonotothen squamifrons larvae in the Amundsen Sea, Antarctic: implication for a new spawning ground and early life characteristics

Parasites of Three Closely Related Antarctic Fish Species (Teleostei: Nototheniinae) from Elephant Island

BackgroundStudies of parasite communities and patterns in the Antarctic are an important knowledge base with the potential to track shifts in ecological relations and study the effects of climate change on host–parasite systems. Endemic Nototheniinae is the dominant fish group found in Antarctic marine habitats. Through their intermediate position within the food web, Nototheniinae link lower to higher trophic levels and thereby also form an important component of parasite life cycles. The study was set out to gain insight into the parasite fauna of Nototheniops larseni, N. nudifrons and Lepidonotothen squamifrons (Nototheniinae) from Elephant Island (Antarctica).MethodsSampling was conducted at three locations around Elephant Island during the ANT-XXVIII/4 expedition of the research vessel Polarstern. The parasite fauna of three Nototheniine species was analysed, and findings were compared to previous parasitological and ecological research collated from a literature review.ResultsAll host species shared the parasites Neolebouria antarctica (Digenea), Corynosoma bullosum (Acanthocephala) and Pseudoterranova decipiens E (Nematoda). Other parasite taxa were exclusive to one host species in this study. Nototheniops nudifrons was infected by Ascarophis nototheniae (Nematoda), occasional infections of N. larseni with Echinorhynchus petrotschenkoi (Acanthocephala) and L. squamifrons with Elytrophalloides oatesi (Digenea) and larval tetraphyllidean Cestoda were detected.ConclusionAll examined fish species’ parasites were predominantly euryxenous regarding their fish hosts. The infection of Lepidonotothen squamifrons with Lepidapedon garrardi (Digenea) and Nototheniops larseni with Echinorhynchus petrotschenkoi represent new host records. Despite the challenges and limited opportunities for fishing in remote areas, future studies should continue sampling on a more regular basis and include a larger number of fish species and sampling sites within different habitats.

Thermal sensitivity of cell metabolism of different Antarctic fish species mirrors organism temperature tolerance

Despite cold adaptation, Antarctic fish show lower growth than expected from the van’t Hoff’s Q10 rule. Protein synthesis is one of the main energy-consuming processes, which is downregulated under energy deficiency. Considering the effect of temperature on growth performance, we tested if temperature-dependent cellular energy allocation to protein synthesis correlates with temperature-dependent whole-animal growth and thus thermal tolerance. Cell respiration and energy expenditure for protein synthesis were determined in hepatocytes of the circumpolar-distributed Antarctic eelpout Pachycara brachycephalum after warm acclimation (0 °C vs 5 °C) and, of two notothenioids the sub-Antarctic Lepidonotothen squamifrons and the high-Antarctic icefish Chionodraco hamatus. We used intermittent-flow respirometry to analyse cellular response to acute warming from 5 to 10 °C (P. brachycephalum) and from 1 to 5 °C (L. squamifrons, C. hamatus). Warming-induced rise in respiration was similar between 0- and 5 °C-acclimated P. brachycephalum and between L. squamifrons and C. hamatus. Irrespective of acclimation, warming decreased energy expenditure for protein synthesis in P. brachycephalum, which corresponds to reduced whole-animal growth at temperatures > 5 °C. Warming doubled energy expenditure for protein synthesis in L. squamifrons but had no effect on C. hamatus indicating that L. squamifrons might benefit from warmer waters. The species-specific temperature effect on energy expenditure for protein synthesis is discussed to mirror thermal sensitivity of whole-animal growth performance, thereby paralleling the degree of cold adaptation. Clearly more data are necessary including measurements at narrower temperature steps particularly for C. hamatus and an increased species’ number per ecotype to reinforce presented link between cellular and whole-animal thermal sensitivity.

Early stages of notothenioid fish from Potter Cove, South Shetland Islands

At Potter Cove, King George Island/Isla 25 de Mayo, South Shetland Islands, significant ichthyological research has been conducted in the last three decades, mainly on the general ecology of notothenioid species in demersal stages from young juveniles to adults. Nevertheless, the knowledge of the ichthyoplankton composition in the cove, necessary for the overall comprehension of the dynamics of the fish species life-cycles, remained unexplored. Here, we report the first record of the early stages of Antarctic notothenioids collected in pelagic hauls at Potter Cove in summer 2014 and 2016 at depths of 6–9 m where total bottom depth ranged 30–190 m. The ichthyoplankton was represented by members of the families Harpagiferidae, Nototheniidae and Bathydraconidae. It consists of (1) 37 larval stages (preflexion and postflexion) of the species Harpagifer antarcticus (the most abundant), Psilodraco breviceps, Lepidonotothen squamifrons, Pleuragramma antarcticum and Trematomus scotti, and (2) 15 eggs of Notothenia coriiceps, of which two larvae hatched in the aquarium. Part of this material is illustrated by photographs. The presence of early life stages of fish in the cove is linked to the major influx from the Bransfield Strait and also depends on local environmental conditions (i.e., hydrologic, water circulation). In addition to being a spawning site for Parachaenichthys charcoti, already reported in the literature, nearshore localities of the South Shetland Islands such as Potter Cove appear to also be spawning sites for N. coriiceps, H. antarcticus and Chaenocephalus aceratus.

Spatial distribution pattern and physical – biological interactions in the larval notothenioid fish assemblages from the Bransfield Strait and adjacent waters

AbstractThe Bransfield Strait and adjacent waters represent one of the most important areas of larval retention off the Antarctic Peninsula. The species composition of larval fish assemblages has been described in detail in previous surveys carried out in the area, but the role of environmental parameters influencing the spatial distribution of early life stages was poorly known. By applying generalized additive models and multivariate analyses, we evaluated the role of environmental variables in shaping the small‐scale distribution of larval fish and investigated the spatial structure of the larval assemblage. It consisted of a few dominant notothenioid species, such as Champsocephalus gunnari, Lepidonotothen squamifrons, Lepidonotothen larseni, Pleuragramma antarctica and Trematomus scotti, and several other rarely caught species. Sea water temperature, salinity and sampling depth were the most important factors determining the spatial distribution of fish with different relative contributions, together explaining more than 80% of total deviance observed. Species richness was mostly affected by salinity, probably due to the narrow range of salinity preference by the species. Cluster analysis of abundance and presence data identified six and five distinct groups, respectively, each of them with substantial contributions of single or rarely two species. Differences in reproductive strategies of adult populations and spatial distribution of early life stages driven by different larval behaviour in response to environmental factors contribute to maintaining a well‐structured larval fish assemblage, ensuring spatial and food niche partitioning.

Molecular systematics and taxonomic status of three latitudinally widespread nototheniid (Perciformes: Notothenioidei) fishes from the Southern Ocean.

The taxonomic status of the three nototheniids, Lepidonotothen squamifrons, L. larseni and Gobionotothen marionensis from different localities in the Southern Ocean is re-evaluated at the DNA level. DNA sequence divergences and phylogenetic relationship were estimated using a combined mitochondrial (mtDNA, ND2 and COI) dataset and data for one nuclear gene (S7 intron 1). Phylogenies of both datasets had Lepidonotothen kempi nested within L. squamifrons lineage, with low sequence divergences (0% to 0.4%) between the two nominal species suggesting that they are populations of one species. Therefore, these results do not support the previous splitting of L. squamifrons into different species. Similarly, the L. larseni specimens also represented a single genetic unit (0.3% to 0.6%) with low geographic variation between Atlantic and Indian Ocean specimens, which does not support the splitting of this species into geographically restricted species. The mtDNA phylogeny clearly separated individuals of G. acuta from Kerguelen, Heard and MacDonald Islands from G. marionensis individuals into different clades, with sequence divergence of 2.9% between these clades supporting they are different species.

Multiple independent reduction or loss of antifreeze trait in low Antarctic and sub-Antarctic notothenioid fishes

AbstractAntifreeze glycoprotein (AFGP) in Antarctic notothenioids presumably evolved once at the base of the notothenioid radiation in the Southern Ocean. Some species closely related to the endemic Antarctic notothenioids occur in non-freezing sub-Antarctic waters where antifreeze protection is unnecessary. We examined the antifreeze trait (phenotype and genotype) of these sub-Antarctic species to help infer their evolutionary history and origin. The status of the AFGP genotype (AFGP coding sequences in DNA) and/or phenotype (serum thermal hysteresis) varies widely, from being undetectable in Dissostichus eleginoides and Patagonotothen species from the Falkland Islands, minimal in Marion Island Paranotothenia magellanica and Lepidonotothen squamifrons from the South Sandwich and Bouvet islands, to considerable genotype in the Falkland Islands Champsocephalus esox and Marion Island Harpagifer georgianus. All low Antarctic notothenioid species examined show substantial AFGP trait. Mapping of the AFGP trait status onto ND2 phylogenetic trees of a large sampling of notothenioids revealed that AFGP trait reduction or loss occurred at least three independent times in different lineages.

Cytogenetic diversity of notothenioid fish from the Ross sea: historical overview and updates

Cytogenetics provides a unique platform to study in situ structural, functional, and evolutionary aspects of the genome. As such it holds powerful promise in decoding mechanisms and processes of genome architectural changes and their role in organism’s diversification and evolution. Since the early 80s, such an approach has been applied to the study of the Antarctic notothenioid fishes. In almost three decades, the cytogenetic information has expanded to cover half of the known species inhabiting the high Antarctic waters. Although started 10 years later, cytogenetic studies of species from the Ross sea region have provided valuable contributions to this bulk of knowledge. Here, we synthesize the currently available cytogenetic information on Antarctic notothenioid fishes from the Ross Sea Region, inclusive of both conventional karyotyping and gene mapping. In addition, new karyotypic data on four species (Lepidonotothen squamifrons, Trematomus scotti, T. loennbergii, and T. lepidorhinus) are provided. In discussing these data, specific focus is made on the patterns and subtleties of cytogenetic diversity at inter- and intra-specific levels aiming at contributing to the refinement of the knowledge of fish diversity in a region, the Ross Sea area, whose primary ecological value is widely recognized.

Ecology and distribution of the grey notothen,Lepidonotothen squamifrons, around South Georgia and Shag Rocks, Southern Ocean

AbstractNew information on the biology and ecology of an abundant ‘rockcod’ species,Lepidonotothen squamifrons(family: Nototheniidae), found at South Georgia is presented. Data collected from twenty demersal trawl surveys carried out at South Georgia and Shag Rocks (sub-Antarctic) from 1986–2012 were analysed to investigate distribution, size, maturity and diet. Distribution was patchy with large aggregations in consistent high-density ‘hotspots’ to the east of Shag Rocks and to the west of South Georgia. Fish density was shown to vary between regions of the shelf and between years but there was little evidence of significant changes in catch per unit effort (CPUE) over the duration of the study. Length at first maturity for males and females (37–38 cm, total length) was very similar to that described for the Indian Ocean population. Detailed stomach contents analysis (2005–12) indicated a varied diet dominated by salps/tunicates, but with ontogenetic and depth variations in prey composition.Lepidonotothen squamifronswas shown to be an opportunistic bentho-pelagic forager. Enhanced knowledge of the ecology ofL. squamifronswill be valuable in future research on food web modelling and marine spatial management in the Southern Ocean and to provide baseline data on the ecology of the species in a rapidly changing environment.

Mitochondrial acclimation capacities to ocean warming and acidification are limited in the antarctic Nototheniid Fish, Notothenia rossii and Lepidonotothen squamifrons.

Antarctic notothenioid fish are characterized by their evolutionary adaptation to the cold, thermostable Southern Ocean, which is associated with unique physiological adaptations to withstand the cold and reduce energetic requirements but also entails limited compensation capacities to environmental change. This study compares the capacities of mitochondrial acclimation to ocean warming and acidification between the Antarctic nototheniid Notothenia rossii and the sub-Antarctic Lepidonotothen squamifrons, which share a similar ecology, but different habitat temperatures. After acclimation of L. squamifrons to 9°C and N. rossii to 7°C (normocapnic/hypercapnic, 0.2 kPa CO2/2000 ppm CO2) for 4–6 weeks, we compared the capacities of their mitochondrial respiratory complexes I (CI) and II (CII), their P/O ratios (phosphorylation efficiency), proton leak capacities and mitochondrial membrane fatty acid compositions. Our results reveal reduced CII respiration rates in warm-acclimated L. squamifrons and cold hypercapnia-acclimated N. rossii. Generally, L. squamifrons displayed a greater ability to increase CI contribution during acute warming and after warm-acclimation than N. rossii. Membrane unsaturation was not altered by warm or hypercapnia-acclimation in both species, but membrane fatty acids of warm-acclimated L. squamifrons were less saturated than in warm normocapnia−/hypercapnia-acclimated N. rossii. Proton leak capacities were not affected by warm or hypercapnia-acclimation of N. rossii. We conclude that an acclimatory response of mitochondrial capacities may include higher thermal plasticity of CI supported by enhanced utilization of anaplerotic substrates (via oxidative decarboxylation reactions) feeding into the citrate cycle. L. squamifrons possesses higher relative CI plasticities than N. rossii, which may facilitate the usage of energy efficient NADH-related substrates under conditions of elevated energy demand, possibly induced by ocean warming and acidification. The observed adjustments of electron transport system complexes with a higher flux through CI under warming and acidification suggest a metabolic acclimation potential of the sub-Antarctic L. squamifrons, but only limited acclimation capacities for N. rossii.

Comparative population genetics of seven notothenioid fish species reveals high levels of gene flow along ocean currents in the southern Scotia Arc, Antarctica

The Antarctic fish fauna is characterized by high endemism and low species diversity with one perciform suborder, the Notothenioidei, dominating the whole species assemblage on the shelves and slopes. Notothenioids diversified in situ through adaptive radiation and show a variety of life history strategies as adults ranging from benthic to pelagic modes. Their larval development is unusually long, lasting from a few months to more than a year, and generally includes a pelagic larval stage. Therefore, the advection of eggs and larvae with ocean currents is a key factor modulating population connectivity. Here, we compare the genetic population structures and gene flow of seven ecologically distinct notothenioid species of the southern Scotia Arc based on nuclear microsatellites and mitochondrial DNA sequences (D-loop/cytochrome b). The seven species belong to the families Nototheniidae (Gobionotothen gibberifrons, Lepidonotothen squamifrons, Trematomus eulepidotus, T. newnesi) and Channichthyidae (Chaenocephalus aceratus, Champsocephalus gunnari, Chionodraco rastrospinosus). Our results show low-population differentiation and high gene flow for all investigated species independent of their adult life history strategies. In addition, gene flow is primarily in congruence with the prevailing ocean current system, highlighting the role of larval dispersal in population structuring of notothenioids.

Thermal Tolerance of Antarctic Notothenioid Fishes Correlates with Level of Circulating Hemoglobin

The West Antarctic Peninsula region is experiencing some of the most rapid elevations in temperature of any marine environment. We assessed thermal tolerance of white- and red-blooded Antarctic notothenioid fishes inhabiting these waters, using a modified critical thermal maximum (CT(max)) design. Temperature was elevated acutely from ambient at a constant rate of 3.6°C h(-1), and CT(max) was defined as the temperature where animals lost righting response. CT(max) temperatures of white-blooded icefishes Chionodraco rastrospinosus (13.3° ± 0.2°C) and Chaenocephalus aceratus (13.9° ± 0.4°C) were significantly lower than those of red-blooded fishes Gobionotothen gibberifrons (15.5° ± 0.2°C) and Notothenia coriiceps (17.1° ± 0.2°C). Lepidonotothen squamifrons, a red-blooded species with low hematocrit, exhibited a CT(max) (14.2° ± 0.4°C) that was significantly lower than that of the other red-blooded animals and similar to that of icefishes. A strong relationship between CT(max) and hematocrit (r(2) = 0.76) suggests that the oxygen-carrying capacity of blood may partially dictate acute lethal temperature. Despite a short treatment duration, we detected a rise in the mRNA level of hypoxia response gene HIF-1α in N. coriiceps heart tissue. One-week exposure to 4°C had no effect on the CT(max) of N. coriiceps, indicating an inability to compensate for rising temperature under these experimental conditions. Our results suggest that icefishes are particularly sensitive to temperature elevation because of a lack of hemoglobin and may be a sentinel taxon for climate change.

Western Antarctic fish species and biomass diversity

Of the 168 fish species living in the Western Antarctic, 104 species belonging to 20 families occur in the South Shetland area: 39 species from 10 families have been found in the Admiralty Bay, 91 species (29 families) in theSouth Georgia area; the South Orkney region hosts 74 species from 18 families while the near Antarctic Peninsula shelf 71 species from 19 families. The respective figures were lower in the Southern Sandwich area, amounting to 44 species from 17 families. Endemic species amounted to 61.2%, the remaing 38.8% being cosmopolitan. The South Georgia area and the neighbouring Shag Rocks area differed also in the composition and biomass of several commercially harvested fish species, such as Pseudochaenichthys georgianus Norman, 1937, Notothenia rossii Richardson, 1844, Patagonotothen guntheri Norman, 1937 or Lepidonotothen squamifrons Gunther, 1880. The South Shetland and Antarctic Peninsula regions were also distinguished from the South Georgia region by the presence of Champsocephalus gunnari Lonnberg, 1905 and above all, by the biomass of Gobionotothen gibberifrons Lonnberg, 1905, which is present in the former, but not found in the latter of the areas.

Seasonal relative abundance of fish larvae inshore at Îles Kerguelen, Southern Ocean

Ichthyoplankton sampling was conducted seasonally with 36 surveys between spring 1989 and spring 1992 in four bays in the Kerguelen archipelago: Morbihan, Baleiniers, Choiseul and Audierne. Golfe des Baleiniers is open to the shelf whereas Choiseul and Audierne are long fjords. Golfe du Morbihan is a very large and protected area open to the shelf at its eastern end. Larvae of neritic species were abundant outside whereas larvae of inshore species were abundant inside the Golfe du Morbihan. Larval Lepidonotothen squamifrons were detected during summer every year whereas larvae of Champsocephalus gunnari were observed in only two years, mainly in the northern coastal zone. For both species, our results support coastal spawning grounds in addition to those on the shelf slope. Larvae of the mesopelagic fish Krefftichthys anderssoni were dominant primarily during winter; this was linked to homogenisation of the water column over the shelf and the coastal zone. Larvae of Notothenia cyanobrancha were present throughout the year everywhere, which is linked to the year long pelagic earlylife-history phase.

The composition of the coastal fish fauna around Elephant Island (South Shetland Islands, Antarctica)

The composition of the coastal fish fauna around Elephant Island (northern South Shetland Islands) was investigated during seven bottom trawl surveys of FRV “Walther Herwig”, FV “Polarstern” and FRV “Yuzhmorgeologiya” from 1981 to 1998. Low-Antarctic (or lesser or peri-Antarctic) fish species were the predominant element of the coastal fish fauna. Large-scale fishing from 1978 to 1981 reduced stock sizes of the most abundant species Champsocephalus gunnari and Notothenia rossii to the extent that only a small fraction of the initial stock remained. After the period of intensive fishing, Gobionotothen gibberifrons became the most abundant species around the island. The by-catch species, which had probably been less affected by harvesting, recovered by the end of the 1980s/beginning of the 1990s. Fish biomass was highest in the 100- to 400-m depth range. An MDS plot revealed the existence of five groups of species that overlapped in their distribution to some extent. One important factor that separated the five groups was depth. Other factors that might have been important in structuring the vertical distribution of the fish fauna, such as bottom topography and sediment type, could not be investigated. Species composition was dominated by a few abundant low-Antarctic species. In four of the five groups, G. gibberifrons was by far the most abundant species, after C. gunnari and N. rossii had been largely eliminated due to fishing. Only in the 100- to 200-m depth range was C. gunnari more abundant than G. gibberifrons. In the 400- to 500-m depth stratum, a high-Antarctic species, Chionodraco rastrospinosus, and Lepidonotothen squamifrons, a species of Patagonian origin which lacks antifreeze glycopeptides, gained some importance. Species richness showed a positive trend with increasing depth. Evenness and Hill's N1 index were highest in the shallowest and deepest depth strata. Hill's N2 index was lowest in depth strata 3 and 4, which had the most even distribution of the abundant fish species.

Role of bay, fjord and seamount on the early life history of Lepidonotothen squamifrons from the Kerguelen Islands

Among the Kerguelen Islands' demersal fish, larvae of Lepidonotothen squamifrons are dominant during the summer over the island shelf and surrounding seamounts. Distribution of larval stages from different scientific surveys confirmed the position of the two known spawning grounds (south of the Kerguelen shelf and at the Kerguelen-Heard bank) and may indicate other spawnings on the Skiff bank and in bays and fjords. Different larval cohorts were observed for the shelf and the coastal zone whereas a unique one was observed for Skiff and Kerguelen-Heard seamounts. Larvae from the spawning ground south of the Kerguelen shelf appear in early summer and show a northwards dispersal to the northeastern nearshore zone, the Baleiniers Gulf, following the scheme of fish migration shown by Harden-Jones. Later on, larvae from the northern inshore spawning zone occur in the same area, which presumably then avoid intraspecific competition with the previous larvae. Larval distribution and migration strategy seemed to be in accordance with the island mass or seamount effect under a regular current.

Day and night mesopelagic fish assemblages off the Kerguelen Islands (Southern Ocean)

Mesopelagic fish assemblages were investigated in the Polar Frontal Zone off the Kerguelen Islands during summer 1995, in parallel with a king penguin tracking study. During the day, the upper offshore water layers (0–200 m) have low potential prey diversity and abundance with only three fish species: a lanternfish, Krefftichthys anderssoni, a member of the Muraenolepididae, Muraenolepis marmoratus, and the early stages of the nototheniid, Lepidonotothen squamifrons. The mesopelagic fish community, including the typical myctophids, first appears in the deeper layer (300 m). At night, the surface layer (50 m) is invaded by the mesopelagic Myctophidae Electrona antarctica, Gymnoscopelus braueri, G. piabilis, G. fraseri, G. nicholsi, Protomyctophum bolini and P. tenisoni. Deeper (>100 m), a cline of species assemblages from the coast to offshore is observed.

Food and feeding ecology of the neritic-slope forager black-browed albatross and its relationships with commercial fisheries in Kerguelen waters

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 207:183-199 (2000) - doi:10.3354/meps207183 Food and feeding ecology of the neritic-slope forager black-browed albatross and its relationships with commercial fisheries in Kerguelen waters Yves Cherel*, Henri Weimerskirch, Colette Trouvé Centre d¹Etudes Biologiques de Chizé, UPR 1934 du Centre National de la Recherche Scientifique, 79360 Villiers-en-Bois, France *E-mail: cherel@cebc.cnrs.fr ABSTRACT: Food and feeding ecology of black-browed albatrosses Diomedea melanophrys rearing chicks was studied during 2 austral summers (1994 and 1995) at the Kerguelen Islands. Dietary analysis and satellite tracking were used to estimate potential interactions with commercial fisheries in the area. Fish comprised 73% by fresh mass of albatross diet; other significant food items were penguins (14%) and cephalopods (10%). Twenty-one species of fish (232 individuals) were identified and included mainly nototheniid and channichthyid species. The most important were Dissostichus eleginoides (18.3% by reconstituted mass), Channichthys rhinoceratus (16.9%), Lepidonotothen squamifrons (11.6%), and to a lesser extent, Bathyraja sp. (4.5%) and Notothenia cyanobrancha (4.5%). The cephalopod diet was dominated by 3 taxa, the ommastrephid squids Todarodes sp. (7.6%) and Martialia hyadesi (3.6%), and the octopus Benthoctopus thielei (2.4%). Satellite tracking indicated that during trips lasting 2 to 3 d, albatrosses foraged mainly over the outer shelf and inner shelf-break of the Kerguelen Archipelago. Birds moved to northern, eastern and southern waters, but never to the western Kerguelen shelf where there was a commercial longline fishery for D. eleginoides. Interactions with trawlers targetting D. eleginoides and Champsocephalus gunnari were of minor importance in the northern shelf. There, offal from D. eleginoides was available to the birds; fish and cephalopod bycatch were negligible. Most of the natural prey of black-browed albatrosses are primarily benthic and semipelagic organisms not known to occur near the surface. Since we demonstrate that most of them were not scavenged behind fishing vessels, the way albatrosses catch demersal organisms remains a mystery. KEY WORDS: Cephalopods · Benthic prey · Diet · Fish · Procellariiformes · Satellite tracking Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 207. Online publication date: November 22, 2000 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2000 Inter-Research.