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  • 1
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary From October 10, 1979 to August 26, 1981 we investigated the effect of physical disturbance, herbivory and algal-algal competition on the dynamics of the Macrocystis community near Valdivia, Chile. The most abundant herbivore, Tegula atra, was continuously removed from one of two sites with high initial Tegula density (control and Tegula-removal rocks) and added to one of two sites where Tegula was initially absent (Tegula-addition and addition-control rocks). Macrocystis was rare at the beginning of the study. From October 1980 to April 1981 we continuously removed Macrocystis from an additional rock near the addition-control rock. On each site the response of the algal community was monitored by photographing 9, 0.25 m2 permanent quadrats at 2–4 week intervals. Tegula had little effect on Macrocystis and there were no other important herbivores present. Each summer Macrocystis dominated all 4 sites of the Tegula experiment and Tegula migrated towards the intertidal to feed. Macrocystis was reduced each winter by winter storms, the holdfasts (but not the canopy) surviving the first winter but not the second. The Macrocystis removal rock was dominated by lower growing perennial algae, indicating a competitive hierarchy among the algae of the form: Macrocystis〉perennial algae〉ephemeral algae〉encrusting algae. Except for the presence of a competitive hierarchy among the algae and the importance of winter storms, Chilean kelp communities share few of the organizational features of their northern hemisphere counterparts. Marine mammals (excluding man) do not prey on algal consumers (Tegula and the urchin, Loxechinus albus) and these consumers have little effect on perennial macroscopic algae. Urchins apparently feed only on drift algae. Species richness in the algal community is low.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The presence of empty shells of Laternula elliptica that provide refuge sites for juvenile fishes on the soft-bottom surface of South Bay, Antarctica, has been difficult to explain because this bivalve normally lives deeply buried (〉50 cm). L. elliptica individuals unburied and aggregated at the surface by the action of icebergs could be consumed by mobile predators. This paper examines experimentally both burying rates and predation upon unburied L. elliptica in the field at South Bay. Live and intact L. elliptica were hand-collected by diving, and separated in 16 groups of 10 each, and placed on mud-sand bottoms protected from the ice disturbance at a depth of 17 m in South Bay. Eight groups were confined by open wooden frames so as to exclude predators, mainly star-fish and gastropods, the other eight remained as control. Species and number of predators and burying rates were estimated during 23 days. Within the first 24 h, 30% of the bivalves buried themselves, after which, rates fell abruptly. By the end of the day 23, only 60% had successfully buried; of the 40% which remained unburied, 20% were consumed by the following sequence of predators: Odontaster validus, Cryptasterias turqueti, Parborlasia corrugatus, Neobuccinum eatoni and two species of amphipods; all completely consumed one bivalve in 5–7 days. The 20% that remained unburied constituted potential prey though they showed no signs of being attacked by O. validus during the observation period. In addition to serving as prey, L. elliptica provides empty and intact shells used as refuge sites by juvenile fishes.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 80 (1981), S. 241-250 
    ISSN: 1573-5117
    Keywords: antarctic fishes ; amphipods ; food habit ; electivity ; predation ; community organization ; intertidal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The diet of Harpagifer bispinis (Pisces: Nototheniidae) from two localities of the South Shetland Archipelago was studied. Simultaneous to the capture of H. bispinis and at the same sites the availability of food was considered, and amphipod diversity was compared with the density of Harpagifer. It was found that three quarters of the fish fed only on amphipods (mainly Gondogeneia antarctica) and for the rest amphipods were also the main component, even when other prey species were available. The high selectivity of G. antarctica is due to its high mobility and to the fact that Harpagifer is an ambush feeder. At different predator densities the amphipod fraction of the community appears to be highly modified by the predator both numerically and in species evenness. We postulate that Harpagifer can be a key species in structuring the mobile epibenthic community, even when this environment is subject to strong physical stress.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-5117
    Keywords: food habit ; antarctic fishes ; Notothenia gibberifrons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The dietary composition of the antarctic fish Notothenia gibberifrons Lönnberg in a depth gradient was studied, from sea level until 200 meters in South Bay, Doumer Island, West Antarctic. The diet of this species varied across the depth gradient. Stomachs from specimens captured between the surface and 100 m. depth usually contained mobile benthic organisms, principally Amphipods. Those from below 150 m. had eaten almost sesile benthic organisms, principally Bivalvia species. Specimens sampled in the layer between the above-mentioned levels contained a mixture of items, some corresponding to the upper and others to the lower sections. Based on the presented evidence the feeding pattern of this species is discussed.
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  • 5
    Publication Date: 2021-05-19
    Description: Chile holds globally important colonies of endangered and endemic seabird species, and globally vulnerable nonbreeding species visit its waters. One of the major threats for seabirds in Chilean waters is the impact of fishing activities, both industrial and artisanal, which overlap with seabird breeding and foraging areas. Bycatch in fisheries threatens 27 identified species and two groups of unidentified albatrosses and penguins, with the Black-browed Albatross Thalassarche melanophrys as the species most related to bycatch events. Responding to the international call for the voluntary adoption of a plan to reduce the impacts of fisheries on seabirds, Chile generated a National Plan of Action (PAN-AM/Chile) to monitor seabird bycatch, and to mitigate threats to seabirds with emphasis on industrial longline fisheries. Following the successful reduction of seabird bycatch in the demersal longline fishery for Patagonian toothfish Dissostichus eleginoides , with zero individuals caught during 2006, Chile is extending the PAN-AM/Chile to include other fisheries that use gear known to cause incidental mortality, such as trawl, purse seine, and gillnets. This initiative is supported by actions associated with the creation of a national scientific committee for biodiversity, and new collaborative research platforms under the auspices of the Chilean Undersecretariat for Fisheries and Aquaculture
    Description: Chile cuenta con importantes colonias a nivel global de especies de aves marinas endémicas y en peligro, así como especies no reproductivas globalmente vulnerables que visitan sus aguas. Una de las mayores amenazas para las aves marinas en aguas chilenas es el impacto de las actividades pesqueras, tanto industriales y artesanales, las cuales se sobreponen con áreas de reproducción y alimentación de aves marinas. Estas amenazan 27 especies identificadas y dos grupos de albatross y pingüinos no identificados, con el Albatros de ceja negra Thalassarche melanophrys como la especie más relacionada a eventos de captura incidental. Respondiendo al llamado internacional para la adopción voluntaria de un plan para reducir los impactos de las pesquerías en aves marinas, Chile generó un Plan de Acción Nacional (PAN-AM/Chile) para monitorear la captura incidental de aves marinas y mitigar amenazas con énfasis en pesquerías industriales de palangre. Seguido a la exitosa reducción de la captura incidental en la pesquería demersal de palangre para Bacalao de profundidad Dissostichus eleginoides, con cero individuos capturados durante 2006, Chile está ampliando el PAN-AM/Chile para incluir otras pesquerías que usan artes de pesca con conocida mortalidad incidental, tales como arrastre, cerco y redes agalleras.
    Description: Published
    Keywords: Seabirds ; By catch
    Repository Name: AquaDocs
    Type: Journal Contribution , Not Known
    Format: pp.1-12
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  • 6
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    In:  http://aquaticcommons.org/id/eprint/8942 | 403 | 2012-06-27 16:54:54 | 8942 | United States National Marine Fisheries Service
    Publication Date: 2021-06-29
    Description: Feeding habits and feeding strategy of red rockfish (Sebastes capensis) were studied from fish captured along most of the range of this species in coastal waters of South America. Stomach contents of 613 individuals, collected during 2003, were analyzed. Fish were obtained from six locations along the Chilean (23°S to 46°S) and Argentinian (43°S) coasts. The main prey items were Mysidacea (75.06% IRI), Osteichthyes (6.29% IRI),and Rhynchocinetes typus (6.03% IRI). Predator sex and size did not significantly affect the diet, but significant differences were found between locations. Four geographical areas, discriminated by prey occurrence and frequencies, were determined: three on the Pacific coast and one on the Atlantic coast. These areas correspond roughly with biogeographic zones described for the Chilean and southern Argentinian coasts. The feeding strategy index (FSI) indicated a specialized feeding strategy for S. capensis for most of its range. However, the FSI does not include the behaviour of a predator, and the FSI must be interpreted carefully for fishes like S. capensis that are passive ambush feeders. The abundance and availability of different prey may explain both the geographic differences in dietary composition and the specialized feeding strategy of S. capensis.
    Keywords: Biology ; Ecology ; Fisheries
    Repository Name: AquaDocs
    Type: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 489-497
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  • 7
    Publication Date: 1977-08-01
    Print ISSN: 0018-8158
    Electronic ISSN: 1573-5117
    Topics: Biology
    Published by Springer
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  • 8
    Publication Date: 1981-06-01
    Print ISSN: 0018-8158
    Electronic ISSN: 1573-5117
    Topics: Biology
    Published by Springer
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  • 9
  • 10
    Publication Date: 2013-06-01
    Print ISSN: 0716-078X
    Electronic ISSN: 0717-6317
    Topics: Biology , Geosciences
    Published by BioMed Central
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