Changes in diversity and composition of fish species in the Southern Benguela Ecosystem of Namibian
dissolved oxygen
,
Henties Bay
,
Hierarchical Cluster Analysis
,
Namibian coast
,
Oranjemund
,
Seafloor depths
,
species composition
,
species diversity
,
total body mass
Abstract:
Species diversity and composition of fish in bottom-trawling were investigated in the Namibian waters between Oranjemund and Henties Bay. Sampling followed a systematic transects design, along latitude gradients (28 - 22°S) at different seafloor depths (100 - 500 m). In total 21 transects were sampled containing 105 stations. At each trawled station the whole catch were sorted into species type and the total body mass (kg) of each fish species was recorded. Results indicated significant differences in means of fish species diversity at different seafloor depths. The Hierarchical Cluster Analysis indicated a complex interaction of gradients which have influenced the pattern in species composition. Differences in species diversity of fish at seafloor depths might be a result of absence of disturbances by bottom-trawling at shallower depths. It was concluded that environmental variability’s of the Namibian coast influence fish species composition.
Keywords:
Seafloor depths, species diversity, species composition.
Authors:
Nashima FP.
Institution:
University of Namibia
Corresponding author:
Nashima FP.
Article Citation:
Nashima FP.
Changes in diversity and composition of fish species in the Southern Benguela Ecosystem of Namibian.
Journal of Research in Ecology (2012) 1: 037-043
Dates:
Received: 24 Mar 2012 Accepted: 16 Apr 2012 Published: 28 Jun 2012
License:
This Open Access article is governed by the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which gives permission for unrestricted use, non-commercial, distribution, and reproduction in all medium, provided the original work is properly cited.
References:
Barnard P. (Ed.). 1998. Biological diversity in Namibia: A country study. Windhoek: National Biodiversity task force. 191.
Binu T, Chandrashekara UM and Rajendran A. 2011. Floristic diversity along an altitudinal gradient of Mannavan Shola forest in Southern Western Ghats of Kerala. Journal of Research in Biology 2:101-109.
Brower JE and Zar JH. 1984. Field and laboratory methods for general ecology. 2ndEdition. Dubuque, IA: Wm. C. Brown publishers. 273.
Bruchert V, Currie B, Peard KR, Lass U, Endler R, Dubecke A, Leipe T, Julies E and Zitzmann S. 2006. Biogeochemical and physical control on shelf anoxia and water column hydrogen sulphide in the Benguela coastal upwelling system off Namibia. Past and Present Water Column Anoxia. 161-193.
Dytham C. 2006. Choosing and using statistics: A biologist guide. 2nd edition. Oxford: Library of Congress Cataloging Publication data. 248.
Gordoa A, Heirich L and Rodergas S. 2006. Bycatch: Complementary information for understanding fish behaviour. Namibian Cape hake (M. capensis and M. paradoxus) as a case study. Journal of Marine Science. 63:1513-1519.
Government Gazette. 2000. Namibia Marine resource act 2000. Windhoek, 2000; 6-12. http://209.88.21.36/opencms/export/sites/default/grnnet/MFMR/Laws_and_Policies/docs/ Marine Act 2000.pdf
Krebs CJ. 1989. Ecological methodology. New York: Harper Collins. 620.
Rathod SR. 2011. Impact of elevation, latitude and longitude on fish diversity in Godavari River. Journal of Research in Biology. 4: 269-275.
Magurran AE. 1988. Ecological diversity and its measurement. Princeton: New Jersey. Princeton University press. 179.
McNaughton SJ and Wolf LL. 1970. Dominance and the niche in ecological systems. Science. 167:131-139.
Oelofsen BW. 1999. Fisheries management: The Namibian approach. ICES Journal of Marine Science. 56:999-1004.
Sakko AL. 1998. Biodiversity of marine habitats. In: Barnard, P. Biological diversity in Namibia–a country study. Windhoek: Namibian National Biodiversity Task Force. 24.
Shannon LV. 1985. The Benguela ecosystem. Evolution of the Benguela physical features and processes. Scotland: Aberdeen, University press.
Van Zyl BJ. 2000. A decade of Namibia fisheries and biodiversity management. 21-24. http://www.unep.org/bpsp/Fisheries/Fisheries%20Case%20Studies/VANZYL. pdf .
Species diversity and composition of fish in bottom-trawling were investigated in the Namibian waters between Oranjemund and Henties Bay. Sampling followed a systematic transects design, along latitude gradients (28 - 22°S) at different seafloor depths (100 - 500 m). In total 21 transects were sampled containing 105 stations. At each trawled station the whole catch were sorted into species type and the total body mass (kg) of each fish species was recorded. Results indicated significant differences in means of fish species diversity at different seafloor depths. The Hierarchical Cluster Analysis indicated a complex interaction of gradients which have influenced the pattern in species composition. Differences in species diversity of fish at seafloor depths might be a result of absence of disturbances by bottom-trawling at shallower depths. It was concluded that environmental variability’s of the Namibian coast influence fish species composition.
Keywords:
Seafloor depths, species diversity, species composition.
Authors:
Nashima FP.
Institution:
University of Namibia
Corresponding author:
Nashima FP.
Article Citation:
Nashima FP.
Changes in diversity and composition of fish species in the Southern Benguela Ecosystem of Namibian.
Journal of Research in Ecology (2012) 1: 037-043
Dates:
Received: 24 Mar 2012 Accepted: 16 Apr 2012 Published: 28 Jun 2012
License:
This Open Access article is governed by the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which gives permission for unrestricted use, non-commercial, distribution, and reproduction in all medium, provided the original work is properly cited.
References:
Barnard P. (Ed.). 1998. Biological diversity in Namibia: A country study. Windhoek: National Biodiversity task force. 191.
Binu T, Chandrashekara UM and Rajendran A. 2011. Floristic diversity along an altitudinal gradient of Mannavan Shola forest in Southern Western Ghats of Kerala. Journal of Research in Biology 2:101-109.
Brower JE and Zar JH. 1984. Field and laboratory methods for general ecology. 2ndEdition. Dubuque, IA: Wm. C. Brown publishers. 273.
Bruchert V, Currie B, Peard KR, Lass U, Endler R, Dubecke A, Leipe T, Julies E and Zitzmann S. 2006. Biogeochemical and physical control on shelf anoxia and water column hydrogen sulphide in the Benguela coastal upwelling system off Namibia. Past and Present Water Column Anoxia. 161-193.
Dytham C. 2006. Choosing and using statistics: A biologist guide. 2nd edition. Oxford: Library of Congress Cataloging Publication data. 248.
Gordoa A, Heirich L and Rodergas S. 2006. Bycatch: Complementary information for understanding fish behaviour. Namibian Cape hake (M. capensis and M. paradoxus) as a case study. Journal of Marine Science. 63:1513-1519.
Government Gazette. 2000. Namibia Marine resource act 2000. Windhoek, 2000; 6-12. http://209.88.21.36/opencms/export/sites/default/grnnet/MFMR/Laws_and_Policies/docs/ Marine Act 2000.pdf
Krebs CJ. 1989. Ecological methodology. New York: Harper Collins. 620.
Rathod SR. 2011. Impact of elevation, latitude and longitude on fish diversity in Godavari River. Journal of Research in Biology. 4: 269-275.
Magurran AE. 1988. Ecological diversity and its measurement. Princeton: New Jersey. Princeton University press. 179.
McNaughton SJ and Wolf LL. 1970. Dominance and the niche in ecological systems. Science. 167:131-139.
Oelofsen BW. 1999. Fisheries management: The Namibian approach. ICES Journal of Marine Science. 56:999-1004.
Sakko AL. 1998. Biodiversity of marine habitats. In: Barnard, P. Biological diversity in Namibia–a country study. Windhoek: Namibian National Biodiversity Task Force. 24.
Shannon LV. 1985. The Benguela ecosystem. Evolution of the Benguela physical features and processes. Scotland: Aberdeen, University press.
Van Zyl BJ. 2000. A decade of Namibia fisheries and biodiversity management. 21-24. http://www.unep.org/bpsp/Fisheries/Fisheries%20Case%20Studies/VANZYL. pdf .
