SAIAB Features » Modelling the effects of climate change on the distribution of shared fishery species in the subtropical Western Indian Ocean

Recorded distributions of slinger, scotsman and catface rockcod (from Heemstra and Heemstra, 2004).      Localities in South Africa and Mozambique in which genetic samples have been collected for all three study species       (Left to right) Mr Rui Mutombene (Mozambique IIP collaborator), Ms Christine Coppinger (MSc Student) and local fish market sellers in Maputo fish market in Mozambique 

Climate change that is linked to the build-up of greenhouse gases and aerosols in the atmosphere is now a widely accepted phenomenon that has lead to increases in surface air and ocean temperatures over the last 50 years (IPCC, 2007). As fish cannot maintain a constant body temperature, and in most cases their body temperature is the same as the water around them, the most obvious changes associated with increasing sea temperatures will be shifts in the distribution and abundance of species or fish assemblages according to their thermal tolerance and ability to adapt (Clark, 2006; Harley et al. 2006). Climate change may pose an even greater threat to species with limited dispersal capabilities (such as endemic species) and to fish stocks under intense exploitation, with depleted stocks, as a result of reduced genetic diversity.

This study uses a species distribution model to explore the extent to which the range of three shared fisheries species endemic to the subtropical Western Indian Ocean might shift in response to climate change (Refer to Figure 1a for the current distribution of these species). Distribution models have been used to predict the effects of climate change on the range of terrestrial species but are less common for marine species. It is important to also understand the existing ‘genetic variation’ which provides the raw material for adaptation as well as the connectivity among different areas and populations of species. Genetic analyses are being undertaken to discover if these species will extend their distribution northwards and whether their overall range may contract or expand. Analyses of historical demographic patterns relative to current distributions will be central to understanding the responses of marine species to changes in their habitats associated with climate change. This project will be completed in 2012.

Research Team:

Principle Investigators:

Dr Monica Mwale, SAIAB

Dr Nicola James, SAIAB

Co-investigators:

Dr Barend Erasmus, WITS University, Johannesburg, South Africa

Dr Almeida T. Guissamulo, Natural History Museum, Universidade. Eduardo Mondlane, Maputo, Mozambique

Mr José S. Halafo, Instituto Nacional de Desenvolvimento da Aquacultura  (INAQUA), Maputo, Mozambique

 

slinger (Chrysoblephus puniceus)                    catface rockcod (Epinephelus andersoni)                  scotsman (Polysteganus praeorbitalis) 



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