Tag recapture data have shown that many fish species display nomadic behaviour, moving to areas outside the reserve where they can be caught by fishermen. In addition, the protection afforded by reserves allow fish to reach larger sizes than fish outside reserves. This is because the biggest and most aggressive fish are usually removed from the population in heavily fished areas. Some fish change sex during their life, so removal of the largest fish may cause a shortage of one sex if the population is overexploited. Protection from fishing allows the poplulation to maintain a balanced sex ratio and a good mix of genes.
Reserves also allow fish to reach their breeding age.
Fish eggs and larvae are transported out of the reserve by ocean currents, thereby replenishing fish stocks in neighbouring areas. If you catch a tagged fish, please remove the tag and return it, together with information on the date, location and size of the catch, to the address on the tag. Your input will help scientists to determine growth rates and migratory movements of fish species important to both recreational and commercial fishermen. The eggs and larvae of Sea Bream are planktonic, so they are at the mercy of currents which disperse them to areas outside the marine reserve. In this way marine reserves supplement fish yields and contribute to the maintenance of the stock in heavily exploited areas White Steenbras Juvenile White Steenbras do not move considerably and are therefore protected by large reserves.