The megazoobenthos of the Scotia Arc islands
Megabenthic epifauna composition and distribution from the Scotia Arc islands based on data collected during the Antarctic summer of 1986-87 is presented. Samples were taken from bottom trawl catches at 345 stations (29 at Shag Rocks, 104 at South Georgia, 8 at the South Sandwich Islands, 93 at the...
| Published in: | Scientia Marina |
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| Main Author: | |
| Format: | Article in Journal/Newspaper |
| Language: | English |
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Consejo Superior de Investigaciones Científicas
1999
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| Online Access: | https://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/view/901 https://doi.org/10.3989/scimar.1999.63s1171 |
| Summary: | Megabenthic epifauna composition and distribution from the Scotia Arc islands based on data collected during the Antarctic summer of 1986-87 is presented. Samples were taken from bottom trawl catches at 345 stations (29 at Shag Rocks, 104 at South Georgia, 8 at the South Sandwich Islands, 93 at the South Orkney Islands, 46 at Elephant Island, and 65 at the South Shetland Islands), from 26 to 643 m depth. Among the most striking features of the faunistic composition of the area, pointed out by multivariate analysis, are the singularity of Shag Rocks, closer to the Magellan region, and of the volcanic South Sandwich Islands, as well as the similarity of South Georgia and the South Orkney Islands and that of the islands nearest to the Antarctic continent, especially Elephant Island and the South Shetlands Islands. This similarity is due to the higher frequency and abundance of the most characteristic taxa in the Antarctic epibenthos, such as sessile suspension feeders (sponges, calcareous bryozoans, pennatulids, crinoids), and motile fauna with a wide variety of trophic strategies (asteroids, holothurians, pycnogonids, large isopods and gammarids). These data confirm the fact that the long-lived suspension-feeder communities, demosponges and hexactinellids, characteristic of the Antarctic epibenthos stretch to the eastern shelf of South Georgia without reaching the north-west of this island, the South Sandwich Islands, and Shag Rocks. Some of the zones with rich communities of sessile filter-feeders, long-lived sponges or reef formations of calcareous bryozoans or serpulids should be proposed as Specially Protected Areas. En el presente trabajo se ofrece una visión de conjunto sobre la composición y distribución de la epifauna megabentónica en las islas del Arco de Escocia. Los datos proceden de las capturas de la campaña española ‘Antártida 8611’, que en 1986-87 realizó 345 arrastres de fondo en la zona (29 en Shag Rocks, 104 en Georgia, 8 en Sandwich, 93 en Orcadas, 46 en Elefante y 65 en Shetlands) a profundidades comprendidas entre 26 y 643 m. Entre los hechos mas interesantes que ponen de manifiesto los análisis multivariantes se encuentran la particularidad de Shag Rocks, el área más próxima a la región de Magallanes, y de las volcánicas islas Sandwich, así como la similaridad de Georgia del Sur y Orcadas y de las islas cercanas al continente antártico, en especial Elefante y Shetlands. Esta similaridad viene determinada por la mayor frecuencia y abundancia de los taxones más característicos del epibentos antártico, tanto suspensívoros sésiles (esponjas, briozoos calcáreos, pennatúlidos, crinoideos), como móviles y con variedad de estrategias tróficas (asteroideos, holoturoideos, picnogónidos, grandes isópodos y gammáridos). La información permite constatar la extensión de las comunidades de suspensívoros de larga vida, demosponjas y hexactinéllidas, características del epibentos antártico, hasta la plataforma este de Georgia, sin que alcancen el noroeste de esta isla, las islas Sandwich, ni los islotes Shag. Algunas de las zonas con ricas comunidades de filtradores sésiles, esponjas de larga vida o formaciones arrecifales de briozoos calcáreos o serpúlidos, podrían ser propuestas para su designación como Áreas Especialmente Protegidas. |
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