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Paul Brickle - One of the best experts on this subject based on the ideXlab platform.
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corallina corallinales rhodophyta from tristan da cunha and the Falkland Islands implications for south atlantic biogeography
European Journal of Phycology, 2021Co-Authors: Juliet Brodie, Paul Brickle, Stephen J Russell, Leanne A Melbourne, Robert J Mrowicki, Sue ScottAbstract:A molecular and morphological taxonomic study of Corallina (Corallinales, Rhodophyta) from Tristan da Cunha and the Falkland Islands revealed Corallina chamberlainiae J.Brodie & R.Mrowicki sp. nov....
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the fungal ecology of seabird nesting sites in the Falkland Islands indicates a niche for mycoparasites
Fungal Ecology, 2018Co-Authors: Jacob Hargreaves, Paul Brickle, Pieter Van WestAbstract:Abstract Soil fungal communities are complex and heterogeneous, possessing important functions in most terrestrial ecological systems. Their study has been advanced due to the development of high-throughput sequencing, which allow for complex fungal communities to be described with techniques such as metabarcoding. The Falkland Islands contain large populations of breeding seabirds; one such internationally recognised area is Saunders Island, located off the coast of the West Falkland. It contains breeding populations of gentoo penguins ( Pygoscelis papua ), Magellanic penguins ( Spheniscus magellanicus ), black-browed albatross ( Thalassarche melanophris ), king penguins ( Aptenodytes patagonicus ) and western rockhopper penguins ( Eudyptes chrysocome chrysocome ). The fungal communities of these sites were investigated using a fungal metabarcode approach. We found these sites contain a large spatial heterogeneity, with communities that are dominated by saprotrophic fungi. However, we noticed that the most abundant species tended to be known mycoparasites. We hypothesise the fungal communities in system undergo a ‘boom-bust’ cycle of varying alpha diversity which is dependent upon the breeding populations, and driven by highly competitive mycoparasitic fungi.
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A comparison of sampling methods for seawater microplastics and a first report of the microplastic litter in coastal waters of Ascension and Falkland Islands
Marine Pollution Bulletin, 2018Co-Authors: Dannielle S Green, Louise Kregting, David James Blockley, Marushka Da Costa, Bas Boots, Paul Brickle, Quentin G CrowleyAbstract:Abstract To date there is no gold standard for sampling microplastics. Zooplankton sampling methods, such as plankton and Neuston nets, are commonly used to estimate the concentrations of microplastics in seawater, but their ability to detect microplastics is limited by their mesh size. We compared different net-based sampling methods with different mesh sizes including bongo nets (>500 μm), manta nets (>300 μm) and plankton nets (>200 μm and >400 μm) to 1 litre bottle grabbed, filtered (0.45 μm) samples. Concentrations of microplastics estimated using net-based methods were ~3 orders of magnitude less than those estimated by 1 litre grab samples. Some parts of the world with low human populations, such as Ascension Island and the Falkland Islands, lack baseline data on microplastics. Using the bottle grab sampling method we found that microplastic litter was present at these remote locations and was comparable to levels of contamination in more populated coastal regions, such as the United Kingdom.
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winter foraging site fidelity of king penguins breeding at the Falkland Islands
Marine Biology, 2015Co-Authors: Alastair M. M. Baylis, Paul Brickle, Rachael A. Orben, Iain J. Staniland, Pierre A Pistorius, Norman RatcliffeAbstract:Foraging site fidelity has profound consequences for individual fitness, population processes and the effectiveness of species conservation measures. Accordingly, quantifying site fidelity has become increasingly important in animal movement and habitat selection studies. To assess foraging site fidelity in king penguins (Aptenodytes patagonicus) breeding at the Falkland Islands (51.48°S, 57.83°W), we measured overlap in time spent in foraging areas (at a 0.1° × 0.1° grid resolution) between successive foraging trips and foraging route consistency during the creche period. In total, 30 complete foraging trips from seven king penguins were recorded between April and October 2010. King penguins predominantly foraged on the highly productive Patagonian slope, to the north of the Falkland Islands [median foraging trip distance 213 km (SD = 215 km) and duration 12.8 days (SD = 14.7 days)]. Overlap in time spent in an area on consecutive foraging trips ranged between 2 and 73 % (mean 27 %, SD = 22 %). Bearing during the outbound portion of foraging trips was typically highly repeatable for individual birds, but foraging trip duration and distance were not. Travel during the outbound phase of foraging trips was consistent with the direction of the northward-flowing Falkland Current that may act as a directional cue or facilitate rapid transit to foraging areas. Flexibility in foraging trip distances and durations may be a response to changes in resource availability and changes in the energetic requirements of adults and chicks over an extended breeding cycle.
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Winter foraging site fidelity of king penguins breeding at the Falkland Islands
Marine Biology, 2015Co-Authors: Alastair M. M. Baylis, Paul Brickle, Rachael A. Orben, Iain J. Staniland, Pierre Pistorius, Norman RatcliffeAbstract:Foraging site fidelity has profound consequences for individual fitness, population processes and the effectiveness of species conservation measures. Accordingly, quantifying site fidelity has become increasingly important in animal movement and habitat selection studies. To assess foraging site fidelity in king penguins ( Aptenodytes patagonicus ) breeding at the Falkland Islands (51.48°S, 57.83°W), we measured overlap in time spent in foraging areas (at a 0.1° × 0.1° grid resolution) between successive foraging trips and foraging route consistency during the crèche period. In total, 30 complete foraging trips from seven king penguins were recorded between April and October 2010. King penguins predominantly foraged on the highly productive Patagonian slope, to the north of the Falkland Islands [median foraging trip distance 213 km (SD = 215 km) and duration 12.8 days (SD = 14.7 days)]. Overlap in time spent in an area on consecutive foraging trips ranged between 2 and 73 % (mean 27 %, SD = 22 %). Bearing during the outbound portion of foraging trips was typically highly repeatable for individual birds, but foraging trip duration and distance were not. Travel during the outbound phase of foraging trips was consistent with the direction of the northward-flowing Falkland Current that may act as a directional cue or facilitate rapid transit to foraging areas. Flexibility in foraging trip distances and durations may be a response to changes in resource availability and changes in the energetic requirements of adults and chicks over an extended breeding cycle.
Alastair M. M. Baylis - One of the best experts on this subject based on the ideXlab platform.
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framework for mapping key areas for marine megafauna to inform marine spatial planning the Falkland Islands case study
Marine Policy, 2018Co-Authors: Amelie A Auge, Dee P Boersma, Alastair M. M. Baylis, Filippo Galimberti, Andy Black, Paulo Catry, Sarah Crofts, Maria P Dias, Ben Lascelles, Jose Pedro GranadeiroAbstract:Abstract Marine Spatial Planning (MSP) is becoming a key management approach throughout the world. The process includes the mapping of how humans and wildlife use the marine environment to inform the development of management measures. An integrated multi-species approach to identifying key areas is important for MSP because it allows managers a global representation of an area, enabling them to see where management can have the most impact for biodiversity protection. However, multi-species analysis remains challenging. This paper presents a methodological framework for mapping key areas for marine megafauna (seabirds, pinnipeds, cetaceans) by incorporating different data types across multiple species. The framework includes analyses of tracking data and observation survey data, applying analytical steps according to the type of data available during each year quarter for each species. It produces core-use area layers at the species level, then combines these layers to create megafauna core-use area layers. The framework was applied in the Falkland Islands. The study gathered over 750,000 tracking and at-sea observation locations covering an equivalent of 5495 data days between 1998 and 2015 for 36 species. The framework provides a step-by-step implementation protocol, replicable across geographic scales and transferable to multiple taxa. R scripts are provided. Common repositories, such as the Birdlife International Tracking Database, are invaluable tools, providing a secure platform for storing and accessing spatial data to apply the methodological framework. This provides managers with data necessary to enhance MSP efforts and marine conservation worldwide.
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Appendix A. Detailed description of archipelago-wide census methods and count error and southern sea lion (Otaria flavescens) breeding colonies at the Falkland Islands.
2016Co-Authors: Alastair M. M. Baylis, Rachael A. Orben, John P. Y. Arnould, Fredrik Christiansen, Graeme C. Hays, Iain J. StanilandAbstract:Detailed description of archipelago-wide census methods and count error and southern sea lion (Otaria flavescens) breeding colonies at the Falkland Islands
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winter foraging site fidelity of king penguins breeding at the Falkland Islands
Marine Biology, 2015Co-Authors: Alastair M. M. Baylis, Paul Brickle, Rachael A. Orben, Iain J. Staniland, Pierre A Pistorius, Norman RatcliffeAbstract:Foraging site fidelity has profound consequences for individual fitness, population processes and the effectiveness of species conservation measures. Accordingly, quantifying site fidelity has become increasingly important in animal movement and habitat selection studies. To assess foraging site fidelity in king penguins (Aptenodytes patagonicus) breeding at the Falkland Islands (51.48°S, 57.83°W), we measured overlap in time spent in foraging areas (at a 0.1° × 0.1° grid resolution) between successive foraging trips and foraging route consistency during the creche period. In total, 30 complete foraging trips from seven king penguins were recorded between April and October 2010. King penguins predominantly foraged on the highly productive Patagonian slope, to the north of the Falkland Islands [median foraging trip distance 213 km (SD = 215 km) and duration 12.8 days (SD = 14.7 days)]. Overlap in time spent in an area on consecutive foraging trips ranged between 2 and 73 % (mean 27 %, SD = 22 %). Bearing during the outbound portion of foraging trips was typically highly repeatable for individual birds, but foraging trip duration and distance were not. Travel during the outbound phase of foraging trips was consistent with the direction of the northward-flowing Falkland Current that may act as a directional cue or facilitate rapid transit to foraging areas. Flexibility in foraging trip distances and durations may be a response to changes in resource availability and changes in the energetic requirements of adults and chicks over an extended breeding cycle.
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Winter foraging site fidelity of king penguins breeding at the Falkland Islands
Marine Biology, 2015Co-Authors: Alastair M. M. Baylis, Paul Brickle, Rachael A. Orben, Iain J. Staniland, Pierre Pistorius, Norman RatcliffeAbstract:Foraging site fidelity has profound consequences for individual fitness, population processes and the effectiveness of species conservation measures. Accordingly, quantifying site fidelity has become increasingly important in animal movement and habitat selection studies. To assess foraging site fidelity in king penguins ( Aptenodytes patagonicus ) breeding at the Falkland Islands (51.48°S, 57.83°W), we measured overlap in time spent in foraging areas (at a 0.1° × 0.1° grid resolution) between successive foraging trips and foraging route consistency during the crèche period. In total, 30 complete foraging trips from seven king penguins were recorded between April and October 2010. King penguins predominantly foraged on the highly productive Patagonian slope, to the north of the Falkland Islands [median foraging trip distance 213 km (SD = 215 km) and duration 12.8 days (SD = 14.7 days)]. Overlap in time spent in an area on consecutive foraging trips ranged between 2 and 73 % (mean 27 %, SD = 22 %). Bearing during the outbound portion of foraging trips was typically highly repeatable for individual birds, but foraging trip duration and distance were not. Travel during the outbound phase of foraging trips was consistent with the direction of the northward-flowing Falkland Current that may act as a directional cue or facilitate rapid transit to foraging areas. Flexibility in foraging trip distances and durations may be a response to changes in resource availability and changes in the energetic requirements of adults and chicks over an extended breeding cycle.
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population trends of gentoo penguins pygoscelis papua breeding at the Falkland Islands
Marine ornithology, 2013Co-Authors: Alastair M. M. Baylis, Sarah Crofts, A C WolfaardtAbstract:The fourth archipelago-wide census of Gentoo Penguins Pygoscelis papua breeding at the Falkland Islands was conducted from 24 October to 8 December 2010. The number of Gentoo Penguins breeding in 2010 was estimated to be 132 321 ± 2 015, the highest number of breeding pairs recorded for this species at the Falkland Islands since the first survey in 1933. The global population of Gentoo Penguins is conservatively estimated to be about 384 000 breeding pairs, of which the Falkland Islands accounts for 34%, probably the largest component of the global population. Annually monitored study colonies accounted for 20% of the total number of Gentoo Penguin breeding pairs at the Falkland Islands in 2010 and proved to be a reliable proxy for archipelago-wide changes in the number of breeding pairs. Recent trends at annually monitored study colonies, combined with archipelago-wide trends, indicate that the number of Gentoo Penguins breeding at the Falkland Islands has increased between 2005 to 2010. However, annual monitoring data also revealed large inter-annual variability in the number of breeding pairs, which makes assessing systematic population changes challenging.
C D Duck - One of the best experts on this subject based on the ideXlab platform.
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the size and status of the population of southern sea lions otaria flavescens in the Falkland Islands
Biological Conservation, 2005Co-Authors: David Thompson, Ian Strange, Michael Riddy, C D DuckAbstract:Abstract Pup production of southern sea lions in the Falkland Islands was estimated to be 80,550 (total population ca. 380,000) in 1937, but by 1965 it had fallen to around 6000; a 93% reduction in under 30 years. We describe the results of an aerial survey of part of the breeding population in 1990 and comprehensive ground counts of the entire population in 1995 and 2003. Results indicate that the decline continued. In 1995, 63 breeding and 42 non-breeding groups were found. Pup production was estimated at 2034 pups; less than 2.7% of the 1930s estimate. All known and potential sites were revisited in 2003. 2747 pups were counted at 68 breeding sites, seven of which were new since 1995. Results indicate that between 1965 and 1990 the population reached a minimum of less than 1.5% of the 1937 population. Since then, pup production has increased at a rate of 8.5% p.a. between 1990 and 1995 and at 3.8% p.a. between 1995 and 2003. The Falklands' trajectory is similar to that of the adjacent Argentinian population. The causes of these declines are not clear. Around 44,000 sea lions were killed in the Falklands between 1935 and 1962, more than 500,000 were taken in Argentina in the same period. We present the results of a simple population model which suggests that, if sea lions migrated between the two areas, the combined hunt may explain the initial decline in the Falklands population. However, the continued decline after 1965 is as yet unexplained.
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foraging behaviour and diet of lactating female southern sea lions otaria flavescens in the Falkland Islands
Journal of Zoology, 1998Co-Authors: Dave Thompson, C D Duck, Bernie J Mcconnell, J GarrettAbstract:This study investigated the foraging behaviour, diving behaviour, movements and diet of lactating southern sea lions in the Falkland Islands. They appeared to be primarily nocturnal, benthic foragers hunting at depths ranging from the surf line down to 250 m, and from just off their breeding sites out to 45 km offshore. Occasional longer trips may extend foraging ranges to over 150 km from breeding sites. Attendance patterns suggest that Falklands' sea lions do not haulout simply to feed their pups. Other factors such as predation and thermoregulation may cause them to come ashore. When at sea they travelled at approximately 1 m s −1 , slower than previous studies of otariids indicated. Absence from the breeding site did not imply continuous foraging; all study animals used remote haulout sites away from their pups. Repeated use of the same areas and the short duration of foraging trips suggest that they were able to catch enough food within a fairly small foraging range. Data on diet support the suggestion that lactating sea lions are mainly benthic foragers. They take a wide range of prey species. The most common cephalopods were Loligo gahi , similar in size to those taken by the fishery. There is therefore potential for competition between the sea lion population and the Loligo trawl fishery. There was considerable overlap between the diet of sea lions and those of Gentoo and Magellanic penguins, which suggests that sea lions may compete with both species.
Iain J. Staniland - One of the best experts on this subject based on the ideXlab platform.
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Appendix A. Detailed description of archipelago-wide census methods and count error and southern sea lion (Otaria flavescens) breeding colonies at the Falkland Islands.
2016Co-Authors: Alastair M. M. Baylis, Rachael A. Orben, John P. Y. Arnould, Fredrik Christiansen, Graeme C. Hays, Iain J. StanilandAbstract:Detailed description of archipelago-wide census methods and count error and southern sea lion (Otaria flavescens) breeding colonies at the Falkland Islands
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winter foraging site fidelity of king penguins breeding at the Falkland Islands
Marine Biology, 2015Co-Authors: Alastair M. M. Baylis, Paul Brickle, Rachael A. Orben, Iain J. Staniland, Pierre A Pistorius, Norman RatcliffeAbstract:Foraging site fidelity has profound consequences for individual fitness, population processes and the effectiveness of species conservation measures. Accordingly, quantifying site fidelity has become increasingly important in animal movement and habitat selection studies. To assess foraging site fidelity in king penguins (Aptenodytes patagonicus) breeding at the Falkland Islands (51.48°S, 57.83°W), we measured overlap in time spent in foraging areas (at a 0.1° × 0.1° grid resolution) between successive foraging trips and foraging route consistency during the creche period. In total, 30 complete foraging trips from seven king penguins were recorded between April and October 2010. King penguins predominantly foraged on the highly productive Patagonian slope, to the north of the Falkland Islands [median foraging trip distance 213 km (SD = 215 km) and duration 12.8 days (SD = 14.7 days)]. Overlap in time spent in an area on consecutive foraging trips ranged between 2 and 73 % (mean 27 %, SD = 22 %). Bearing during the outbound portion of foraging trips was typically highly repeatable for individual birds, but foraging trip duration and distance were not. Travel during the outbound phase of foraging trips was consistent with the direction of the northward-flowing Falkland Current that may act as a directional cue or facilitate rapid transit to foraging areas. Flexibility in foraging trip distances and durations may be a response to changes in resource availability and changes in the energetic requirements of adults and chicks over an extended breeding cycle.
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Winter foraging site fidelity of king penguins breeding at the Falkland Islands
Marine Biology, 2015Co-Authors: Alastair M. M. Baylis, Paul Brickle, Rachael A. Orben, Iain J. Staniland, Pierre Pistorius, Norman RatcliffeAbstract:Foraging site fidelity has profound consequences for individual fitness, population processes and the effectiveness of species conservation measures. Accordingly, quantifying site fidelity has become increasingly important in animal movement and habitat selection studies. To assess foraging site fidelity in king penguins ( Aptenodytes patagonicus ) breeding at the Falkland Islands (51.48°S, 57.83°W), we measured overlap in time spent in foraging areas (at a 0.1° × 0.1° grid resolution) between successive foraging trips and foraging route consistency during the crèche period. In total, 30 complete foraging trips from seven king penguins were recorded between April and October 2010. King penguins predominantly foraged on the highly productive Patagonian slope, to the north of the Falkland Islands [median foraging trip distance 213 km (SD = 215 km) and duration 12.8 days (SD = 14.7 days)]. Overlap in time spent in an area on consecutive foraging trips ranged between 2 and 73 % (mean 27 %, SD = 22 %). Bearing during the outbound portion of foraging trips was typically highly repeatable for individual birds, but foraging trip duration and distance were not. Travel during the outbound phase of foraging trips was consistent with the direction of the northward-flowing Falkland Current that may act as a directional cue or facilitate rapid transit to foraging areas. Flexibility in foraging trip distances and durations may be a response to changes in resource availability and changes in the energetic requirements of adults and chicks over an extended breeding cycle.
Vladimir Laptikhovsky - One of the best experts on this subject based on the ideXlab platform.
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distribution and reproduction of the patagonian toothfish dissostichus eleginoides smitt around the Falkland Islands
Journal of Fish Biology, 2006Co-Authors: Vladimir Laptikhovsky, Alexander I. Arkhipkin, Paul BrickleAbstract:Population characteristics of the Patagonian toothfish Dissostichus eleginoides were investigated based on material collected from both trawl and longline fisheries in Falkland Islands' waters. The fish occurred between 56 and 2122 m and attained 225 cm total length (L T ). Males matured earlier, L T at 50% maturity was 86 cm for males v. 90 cm for females. Subadult fish foraged at depths of 600 m. Spawning occurred on slopes of the Burdwood Bank at c. 1000 m depth with a minor peak in May, and a major peak in July to August. Males arrived at the spawning grounds first. Between spawning peaks both sexes remained around the Burdwood Bank with males occurring at greater depths than females. The Patagonian toothfish in south-east Patagonia and the Falkland Islands had a long juvenile and sub-adult period in the relatively shallow and warm waters of the outer shelf and upper slope unlike that of juveniles in other Patagonian toothfish populations. The migratory life style of the south-west Atlantic population is probably very different from that of other populations, which tend to be resident as they are inclined to inhabit the waters around oceanic Islands and sea mounts with narrow shelf areas.
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the patagonian toothfish fishery in Falkland Islands waters
Fisheries Research, 2005Co-Authors: Vladimir Laptikhovsky, Paul BrickleAbstract:Abstract This paper examines and provides updated information on the status of toothfish stocks within Falkland Islands conservation zones and also provides a historical perspective of the fishery. The Patagonian toothfish has been taken as a bycatch since the trawl fishery was established in the Falkland Islands. However, specialised exploitation of the Patagonian toothfish started with the opening of the Falkland Islands Outer Conservation Zone (FOCZ) in 1994 when demersal longliners started to target this species at depths of greater than 600 m. When compared to trawlers, analysis showed that longline catches were higher in weight but not numbers. Generally longline catches comprised fish of greater than their length at 50% maturity whereas this situation is rare in catches taken by trawlers. Longliner CPUE peaked in the first year of the fishery and gradually declined until 2000–2001 after which it remained relatively stable with a small increase in 2003–2004. The latter is attributed to a strong year class born in 1994. Toothfish recruitment in the Falkland Islands was found to be very variable. Strong year classes seem to occur every 4–5 years. The mean size of toothfish has decreased since the onset of the longline fishery. This decrease mainly occurred between 1994 and 1999, since then the size of toothfish in catches has remained relatively stable. Fox and Schaefer production models show a strong decline in biomass with the current stock size at about 50% of its unexploited state. It is concluded that the fishery is still just within its limits of sustainable use.
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management of the Falkland Islands multispecies ray fishery is species specific management required
Journal of Northwest Atlantic Fishery Science, 2004Co-Authors: R C Wakeford, David J Agnew, J. Pompert, D A J Middleton, Vladimir LaptikhovskyAbstract:A multispecies commercial fishery for rajids has been managed in Falkland Islands waters since 1987. In the absence of detailed biological knowledge and catch-at-age data, management policies currently consider a single assemblage rather than individual species. Simple production models with aggregated catch and effort data are used to estimate sustainable levels of exploitation. Biological data, now available from recent research surveys and an ongoing observer program, provide an opportunity to examine the potential impact of the rajid fishery at a species level. This in turn will help determine whether current management policies are still appropriate. An updated assessment of the northern ray population indicates that the assemblage has been surprisingly robust to fluctuations in fishing pressure. A spatial analysis of the relative abundance of animals showed no evidence of local depletions in biomass. At a species level, a declining trend in the relative abundance of three species (Bathyraja griseocauda, B. multispinus, and an undescribed Bathyraja sp. 3) was found at the same time as an increase in two Rajid species (R. doellojuradoi and R. flavirostris). A preliminary analysis of the distribution and movements of R. flavirostris, coupled with length frequency and maturity data, suggest that this species has a broad distribution, which, unlike B. griseocauda, may not form a resident population within Falkland Island waters. While no loss of diversity has been reported, closure of the once heavily exploited area to the south of the Islands provides at least one refuge for species such as B. griseocauda.
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ontogenetic changes in the feeding habits and dietary overlap between three abundant rajid species on the Falkland Islands shelf
Journal of the Marine Biological Association of the United Kingdom, 2003Co-Authors: Paul Brickle, Vladimir Laptikhovsky, J. Pompert, A. BishopAbstract:The ontogenetic changes in the diet and dietary overlap of three commercially important rajid species inhabiting the slope and shelf waters of the Falkland Islands were investigated. The white dotted skate (Bathyraja albomaculata) was a specialized amphipod and polychaete feeder. The broad nose skate (B. brachyurops) had a diverse diet, consuming a wide variety of crustaceans and fish. The grey tail skate (B. griseocauda) also had a broad diet but consumed a high proportion of amphipods and isopods (e.g. Serolis spp.). Larger individuals of the latter species were more piscivorous and consumed more squid. The diets of all three species showed a marked variation with ontogeny. Dietary overlap was greatest for smaller animals (<30 cm disk width), after which each species became more specialized in their diets. Smaller animals also showed some differences in depth of distribution, which may be an adaptation to reduce inter-specific competition.
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variation in the diet of the patagonian toothfish with size depth and season around the Falkland Islands
Journal of Fish Biology, 2003Co-Authors: Alexander I. Arkhipkin, Paul Brickle, Vladimir LaptikhovskyAbstract:The ontogenetic and seasonal variations in the feeding spectrum were studied in 756 specimens of the Patagonian toothfish Dissostichus eleginoides (16-159 cm total length, L T ) collected on the shelf, continental slope and bathyal waters (67-1960 m depth range) around the Falkland Islands between April 1999 and August 2002. On the shelf, small toothfish ( 60 cm L T ) switched their diet to other large pelagic fishes occurring near the bottom (Macruronus magellanicus and Micromesistius australis australis), again taking mostly one prey item at a time. The diet of medium-size D. eleginoides on the shelf varied seasonally depending on the abundance and migrations of the major prey species. Patagonotothen ramsayi was abundant in the diet throughout the year, whereas L. gahi appeared only from February to October during its offshore seasonal migrations to the depth range of D. eleginoides. During November to January, L. gahi migrated inshore to spawn and disappeared from the toothfish diet, being substituted by M. australis australis which dispersed on the shelf after spawning. After its ontogenetic descent to the lower part of the continental slope (500-1000 m depths), toothfish took less active (than on the shelf) fishes such as Antimora rostrata whilst also feeding on active near-bottom macrourids and skates. In their deepest habitat (>1000m depths), toothfish became a typical opportunistic predator, feeding mainly on relatively small and inactive fishes, squids and prawn-like crustaceans Acanthephyra pelagica and Thymops birsteini. Decrease in hunting activity with depth could be related to a specific adaptation to keep neutral buoyancy by increase of lipid content in white muscles of D. eleginoides with size.