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

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.     

Changes in population parameters and behaviour of blue cod (Parapercis colias; Pinguipedidae) in Long Island—Kokomohua Marine Reserve,Marlborough Sounds,New Zealand

• 1 With the establishment of the 619‐ha Long Island—Kokomohua Marine Reserve in April 1993, a biological monitoring programme designed to investigate changes due to the total no‐take legislation applied to the reserve was initiated.
• 2 Size, distribution and behaviour of blue cod (Parapercis colias; Pinguipedidae) were investigated using baited hooks at reserve and control rubble bottom habitats annually from 1993 to 2000. Blue cod abundance was estimated using visual diver strip transects annually for a period of 9 years from 1992 to 2001.
• 3 A total of 5628 blue cod (2436 reserve and 3192 control specimens) were captured, measured and released. Two years after the reserve was established, the average size of blue cod was 22.4 mm larger inside the reserve compared with control sites outside it.
• 4 Over the duration of the study, the mean length of blue cod captured using baited hooks increased in the no‐take reserve, but declined at the control sites. By the end of the study, in April 2000, the proportion of large blue cod >330 mm in length in the reserve was 35% compared with <1% at the control sites, where recreational fishing activities occurred.
• 5 Blue cod catch rates from experimental fishing in the reserve increased within 11 months of removal of recreational fishing activities and continued to increase up to 47 months, in contrast to the control areas where recreational fishing was permitted, catch rates remained consistently low. Increased catch rates in the reserve were not due to increased blue cod abundance, rather an increase in the proportion of naïve fish in the population.
• 6 From March 1998 to the end of the study, the density of blue cod in the reserve was significantly higher compared with the control sites. This increase was primarily due to an increase in the density of larger blue cod >300 mm length in the reserve and a corresponding small decline in the density of these larger fish at the control sites.
• 7 It is concluded that the cessation of recreational fishing in the reserve had resulted in an increase in blue cod size, catch rate and abundance and also in a change to blue cod behaviour.

Copyright © 2001 John Wiley & Sons, Ltd.     

Evaluation of a Fast Method Based on the Presence of Two Restriction Sites in the Mitochondrial ND5 (mt ND5) Gene for the Identification of Scomber Species

The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus.