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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The diet and feeding of the pelagic goby, sufflogobius bibarbatus, off Namibia

Riaan Brinley Cedras January 2009 (has links)
<p>The general diet of Sufflogobius bibarbatus in the northern Benguela upwelling ecosystem was investigated from gut content analysis in two separate studies. The first study was conducted over two 48 h diel sampling stations onboard the RV Dr. Fridtjof Nansen during a dedicated cruise conducted in January 2006, whilst the second was conducted on cruises of opportunity aboard the RV Welwitschia during 2001 and 2002. The results of both studies indicate that S. bibarbatus has a fairly generalised diet, feeding on benthic and pelagic animals for the most part: phytoplankton was uncommonly reported from the 3739 fish examined. Larger fish ate primarily benthic organisms, whereas smaller individuals include substantial number of pelagic organisms in their diet. There would appear to be a clear relationship between the environment occupied by individuals and their diet: large fish are predominantly demersal and display limited vertical migration, whilst small fish are thought to be more pelagic. Results strongly indicate that this species is opportunistic. The present study sheds new light on the ecology of the species, which is becoming increasingly important in the region.</p>
2

The diet and feeding of the pelagic goby, sufflogobius bibarbatus, off Namibia

Riaan Brinley Cedras January 2009 (has links)
<p>The general diet of Sufflogobius bibarbatus in the northern Benguela upwelling ecosystem was investigated from gut content analysis in two separate studies. The first study was conducted over two 48 h diel sampling stations onboard the RV Dr. Fridtjof Nansen during a dedicated cruise conducted in January 2006, whilst the second was conducted on cruises of opportunity aboard the RV Welwitschia during 2001 and 2002. The results of both studies indicate that S. bibarbatus has a fairly generalised diet, feeding on benthic and pelagic animals for the most part: phytoplankton was uncommonly reported from the 3739 fish examined. Larger fish ate primarily benthic organisms, whereas smaller individuals include substantial number of pelagic organisms in their diet. There would appear to be a clear relationship between the environment occupied by individuals and their diet: large fish are predominantly demersal and display limited vertical migration, whilst small fish are thought to be more pelagic. Results strongly indicate that this species is opportunistic. The present study sheds new light on the ecology of the species, which is becoming increasingly important in the region.</p>
3

The diet and feeding of the pelagic goby, sufflogobius bibarbatus, off Namibia

Cedras, Riaan Brinley January 2009 (has links)
Magister Scientiae - Msc (Biodiversity and Conservation Biology) / The general diet of Sufflogobius bibarbatus in the northern Benguela upwelling ecosystem was investigated from gut content analysis in two separate studies. The first study was conducted over two 48 h diel sampling stations onboard the RV Dr. Fridtjof Nansen during a dedicated cruise conducted in January 2006, whilst the second was conducted on cruises of opportunity aboard the RV Welwitschia during 2001 and 2002. The results of both studies indicate that S. bibarbatus has a fairly generalised diet, feeding on benthic and pelagic animals for the most part: phytoplankton was uncommonly reported from the 3739 fish examined. Larger fish ate primarily benthic organisms, whereas smaller individuals include substantial number of pelagic organisms in their diet. There would appear to be a clear relationship between the environment occupied by individuals and their diet: large fish are predominantly demersal and display limited vertical migration, whilst small fish are thought to be more pelagic. Results strongly indicate that this species is opportunistic. The present study sheds new light on the ecology of the species, which is becoming increasingly important in the region. / South Africa
4

Studies on the integrated feeding of Sufflogobius bibarbatus (von Bonde, 1923) in the Northern Benguela ecosystem using fatty acid biomarkers and stable isotopes (513C, 515N, 834S)

Bank, Megan Geralda van der January 2010 (has links)
Magister Scientiae (Medical Bioscience) - MSc(MBS) / The present study employs a multi-tracer approach to shed light on the integrated feeding of the bearded goby Sufflogobius bibarbatus. The study was conducted between 31 March and 10 April 2008 at two 48 hour stations off the Namibian coast, namely inshore(station A, 120 m) and offshore (station B, 180 m). Isotopes of 513C and 515N suggest that the goby diet at station A and B at the time of the study was primarily composed of the jellyfish Chrysaora fulgida and Aequorea forskalea, which comprised up to 73.85 % and 70.36 % of the goby diets respectively. However the importance of these cnidarian prey items, together with adult euphausiids, benthic polychaetes and shrimp varied with goby size, point of collection and habitat. Spatially pooled 534S results suggest that the sulphidic benthic sediment (containing diatoms and sulphur bacteria) overlying the central shelf off Namibia may contribute 34.2 % to the diet of the goby and that the goby may be able to drive sulphides from the benthos. Fatty acid analyses were limited to data collected only at station B and they suggest that gobies retrieve most of their essential fatty acids from pelagic zooplankton. Furthermore, small gobies at station B were high in the copepod markers 20:1ω9 and 22:1ω11, but their larger counterparts were high in the diatom FA 20:4ω6, 20:5ω3, diatom marker ratios 16:1/16:0 and 20:5ω3/22:6ω3 suggesting that small gobies fed more on pelagic copepods while large gobies fed directly on sedimented diatoms on the benthos. Fatty acid analyses also provided support for sulphur bacterial and jellyfish-feeding amongst gobies. The study highlights the advantages of using multiple trophic tracers to compliment each other, and identifies the bearded goby as an opportunistic feeder that plays an important role in terms of energy transfer within the northern Benguela ecosystem.

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