Direct evidence of limited dispersal of the reef fishParapercis colias (Pinguipedidae) within a marine reserve and adjacent fished areas

Abstract

1. Spillover of organisms from marine reserves may augment adjacent areas, and is often cited as an important reason for the establishment of marine protected areas. Spillover is dependent on residence or limited dispersal of organisms resulting in an increase in their abundance and size within a marine reserve. 2. To investigate movement (i.e. spillover versus residence) we tagged and released 90 blue cod Parapercis colias (Pinguipedidae) at each of four sites, two in and two adjacent to Long Island–Kokomohua Marine Reserve, Marlborough Sounds, New Zealand. The study was done 4–5 years after establishment of the no-take reserve. 3. Abundances of blue cod were similar in and out of the marine reserve, but mean estimated size was 4 cm larger in the reserve than at fished sites. 4. Fewer tag resights were made in the reserve than at fished sites, and tagged blue cod were resighted at greater depths in the reserve than at fished sites. 5. Most resights (75% for fished sites, 73% for reserve sites) were made within 100 m of the tagging sites, and the number of resights declined through time, though tagged individuals were resighted up to 31 months after tagging. 6. The lower number of tag resights at reserve sites, despite the lack of extraction, is consistent with some blue cod at reserve sites moving longer distances than those at fished sites. 7. The greater size of individuals in the reserve and limited dispersal of a proportion of the population show that survivorship of blue cod is increased within marine reserves. 8. Computer simulations based on measured dispersals indicate that even marine reserves of a few hundred metres long-shore extent have the potential to supplement fished populations nearby. 9. These data provide direct evidence of limited dispersal of the most common edible reef fish in the Marlborough Sounds. Blue cod will grow to larger sizes in marine reserves and via spillover will become available to fishers in adjacent areas of contiguous coast. Copyright © 2000 John Wiley & Sons, Ltd.