Marine protected areas can boost fish populations without damaging fishermen’s livelihoods, according to scientists at the University of Cape Town (UCT) who have been studying red roman near Knysna.
Red roman is a sea bream endemic to South Africa, and was a popular fish on restaurant menus until over-fishing led to a significant reduction of stocks.
Many countries have introduced marine protected areas to conserve endangered marine species, much as national parks are designed to protect land-based plants and animals.
But these protected areas have proved controversial, as fishermen feared that closing off parts of their fishing grounds to conserve dwindling fish stocks would force them to travel further to catch fish and make it harder to make a living, UCT’s marine research institute’s Colin Attwood said on Tuesday.
A study by Professor Colin Attwood and his colleagues, published in the journal Nature Communications last month, shows that both fish and fishermen can benefit from marine protected areas.
They analysed 15 years of data on the red roman collected by the Department of Agriculture, Forestry and Fisheries, that covers the period before and after the proclamation of the Goukamma marine protected area between Knysna and Sedgefield.
They found the fishermen’s catch of red roman increased after the marine protected area was declared, but there was no increase in stocks of the fish in any other part of its range.
The scientists suggest there were two mechanisms at play.
Firstly, as fish stocks recovered, the protected fish abandoned their home ranges and strayed outside the marine protected areas, into the range of fishermen. Secondly, there was a boost in egg production in the protected area, and currents carried eggs and young fish beyond its borders.
They also found that the loss of part of the fishermen’s fishing grounds was more than compensated for by an increase in the size of their catches.
The study was relevant to South Africa, where species that had been part of traditional catches for 200 years were severely over-exploited and coastal fishing communities had collapsed, Professor Attwood said. “Many (people) believe that marine protected areas could play a useful role in restoring the abundance of fishes (but) traditional and subsistence fishers are making strong representations to be allowed access to protected areas, citing low catch rates, loss of livelihoods, and in some cases exclusion without consultation.
“The issues are often quite political, but this study has shown that conservation and fishery objectives can both be served by a well-placed marine area .”
The study was also important because it was one of only a handful that had assessed the practical implications of introducing marine protected areas.
Such studies were extremely difficult to conduct, because there was very little time-series data that spans the period before and after the implementation of marine protected areas, Professor Attwood said.