TY - JOUR
T1 - Effects of experimental harvesting on recruitment of an alien mussel Mytilus galloprovincialis
AU - Robinson, Tamara B.
AU - Branch, George M.
AU - Griffiths, Charles L.
AU - Govender, Anesh
N1 - Funding Information:
We would like to acknowledge the National Research Foundation and the Department of Environmental Affairs and Tourism: Marine and Coastal Management Branch who funded this research through the Sea and the Coast Programme II. Additionally, the Marine Biology Research Institute at the University of Cape Town and the Andrew Mellon Foundation provided much appreciated financial support. Barbara Xavier, Paula de Coito, Eleanor Yeld, and Hannah Medd are thanked for their help in the field. [SS]
PY - 2007/6/29
Y1 - 2007/6/29
N2 - Successful fisheries management is underpinned by an understanding of the processes that underlie the population dynamics of exploited stocks. This study considered the effects of experimental harvesting on recruitment of Mytilus galloprovincialis along the west coast of South Africa, where harvesting of this alien species is being contemplated. In particular, the role of settlement habitat availability in the form of adult mussels was analysed. To track the effects of a spectrum of harvesting intensities, five treatments were implemented: F = 0 (i.e. a control), F = 0.3, F = 0.6, F = 0.9 and F = 1. At these harvesting intensities 0%, 30%, 60%, 90% or 100% of mussel biomass was removed respectively at the outset of the experiment. A significant negative exponential relationship (p < 0.01) was found between M. galloprovincialis recruit density and harvesting intensity, with intensities greater than F = 0.3 dramatically reducing recruitment. This pattern was recorded throughout the intertidal zone and remained temporally constant over 2 years. Significant positive linear relationships (p < 0.01) between recruit density and adult mussel biomass or density indicate a strong correlation between availability of settlement habitat and recruitment. It is likely that the high recruit density recorded at low harvesting intensities (2000-20 000 per 0.01 m2) exceeds the level required for population maintenance. However, if settlement habitat is eliminated or significantly reduced, as was achieved by F = 0.3 or above, recruitment may become limiting. Thus, to protect stock replenishment, harvesting of M. galloprovincialis in this region should take place at intensities less than F = 0.3.
AB - Successful fisheries management is underpinned by an understanding of the processes that underlie the population dynamics of exploited stocks. This study considered the effects of experimental harvesting on recruitment of Mytilus galloprovincialis along the west coast of South Africa, where harvesting of this alien species is being contemplated. In particular, the role of settlement habitat availability in the form of adult mussels was analysed. To track the effects of a spectrum of harvesting intensities, five treatments were implemented: F = 0 (i.e. a control), F = 0.3, F = 0.6, F = 0.9 and F = 1. At these harvesting intensities 0%, 30%, 60%, 90% or 100% of mussel biomass was removed respectively at the outset of the experiment. A significant negative exponential relationship (p < 0.01) was found between M. galloprovincialis recruit density and harvesting intensity, with intensities greater than F = 0.3 dramatically reducing recruitment. This pattern was recorded throughout the intertidal zone and remained temporally constant over 2 years. Significant positive linear relationships (p < 0.01) between recruit density and adult mussel biomass or density indicate a strong correlation between availability of settlement habitat and recruitment. It is likely that the high recruit density recorded at low harvesting intensities (2000-20 000 per 0.01 m2) exceeds the level required for population maintenance. However, if settlement habitat is eliminated or significantly reduced, as was achieved by F = 0.3 or above, recruitment may become limiting. Thus, to protect stock replenishment, harvesting of M. galloprovincialis in this region should take place at intensities less than F = 0.3.
KW - Alien species
KW - Harvesting
KW - Mussel
KW - Mytilus galloprovincialis
KW - Recruitment
KW - South Africa
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U2 - 10.1016/j.jembe.2006.12.019
DO - 10.1016/j.jembe.2006.12.019
M3 - Article
AN - SCOPUS:33947713257
SN - 0022-0981
VL - 345
SP - 1
EP - 11
JO - Journal of Experimental Marine Biology and Ecology
JF - Journal of Experimental Marine Biology and Ecology
IS - 1
ER -