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This study reports the response of snapper Pagrus auratus to the establishment of notake status in a marine reserve around the Poor Knights Islands in northeastern New Zealand. The Poor Knights and 2 reference locations, Cape Brett and the Mokohinau Islands, were sampled biannually for 4 yr using baited underwater video (BUV). Following the implementation of full marine reserve status at the Poor Knights in October 1998, snapper showed significant increases in abundance and biomass relative to fished control locations. This was particularly apparent for large snapper (> 270 mm), whose numbers increased rapidly to levels 7.4 times higher in the final survey compared to the initial pre-reserve survey, and total snapper biomass increased by 818%. There was no significant increase in the abundance, biomass or size of snapper at the reference locations over this time. There was a strong seasonal trend in snapper abundance, with higher numbers in autumn (March/April) compared to spring (September/October). The daily batch fecundity was 11 to 18 times higher at the Poor Knights compared to the reference locations. Once fishing ceased in previously partially protected areas, a rapid recovery of snapper ensued, suggesting that partial fishing regulations are ineffective for protecting targeted species. The speed of increase in snapper density resulted from the immigration of adult fish into the reserve, rather than from within-reserve recruitment.

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SynopsisPhysical factors influencing the distribution and abundance of seven common labrid fishes were examined over four rocky reef locations in northeastern New Zealand. Depth and exposure for each species (both within and among sexes) were related to pectoral fin aspect ratio. Each of the four locations (two mainland and two island) displayed distinct labrid assemblages, which were consistent over time, likely due to the influence of the East Auckland Current. There was a consistent depth-related trend for most species, regardless of location. Several species also showed a sex related depth difference. There was also a trend for some species to be associated with certain levels of wave exposure. For most species, the relationship between pectoral fin aspect ratio and the above physical variables was not as strongly evident in this temperate assemblage as has been previously found in tropical reef fish systems. Although some species did follow the predicted shifts in fin aspect ratio with depth and/or exposure, the observed trends were unrelated to fin aspect ratio for many other species. These findings suggest that wave exposure may not be as important for labrids on northeastern New Zealand reefs as it may be in tropical coral reefs systems. The lower fin aspect ratios for New Zealand labrids, compared to tropical labrids, suggest that New Zealand labrids represent a subset of the total pectoral fin diversity in the Labridae. Consequently, the potential for distinct trends in fin aspect ratio and physical variables to be evident may be reduced.

Notolabrus fucicola Richardson, a large common labrid inhabiting rocky reefs around New Zealand and southern Australia, were collected monthly from December 1996 to February 1998 around Kaikoura, New Zealand. They were found to be asynchronous spawners and followed the typical labrid spring-summer seasonal pattern of reproduction from July to December. Compared with other New Zealand labrids that are protogynous hermaphrodites, N. fucicola was found to be a secondary gonochorist, where individuals change sex before maturation. It is a dichromatic species but not sexually dimorphic. It is also monandric where only one morphological male type is present. Despite finding no transitional gonads, it is still possible that particular environmental or social conditions could induce sex change in at least a small proportion of fishes.