A recent study has proven that creating Marine Protected Areas (MPAs) can have a positive effect on spawning, though drifting larvae, for stocks more than 150 kilometres away.
“We already know that marine reserves will grow larger fish and some of them will leave that specific area, what we call spillover – now we’ve clearly shown that fish larvae that were spawned inside marine reserves can drift with currents and replenish fished areas long distances away”, explained Professor Mark Hixon of Oregon State University on the US west coast, one of the authors of the report.
The species studied was Yellow tang (Zebrasoma flavescens), well known among aquarium buffs and representing 80 percent of all fish caught in Hawaii for the aquarium trade. The popularity brought about nine Marine Protection Areas being set up around the Kohala-Kona coast in 1999.
The yellow tang was chosen for the study for its being non-migratory – if a fish is found more than half a mile away from the reef where it has settled, it must have come there already as a larvae.
Through sophisticated methods – including DNA fingerprinting – the researchers were able to establish that many juvenile fish had travelled up to 114 miles (183 kilometres) away from their parents, some of which were sampled from protected areas.
“This is a direct observation, not just a model, that successful marine reserves can sustain fisheries beyond their borders”, Prof. Hixon said, adding that “the life cycle of our study fish is very similar to many species of marine fish, including rockfishes and other species off Oregon. The results are highly relevant to other regions.”