Habitat use by triplefin species (Tripterygiidae) on rocky reefs in New Zealand
Habitat use and nesting sites of 12 triplefin species (Tripterygiidae) were investigated at 26 coastal and offshore rocky reef locations in north-eastern New Zealand. Within these locations, 17 broad-scale habitats and 14 fine-scale habitats were surveyed using visual transects. In terms of broad-scale habitat use, four species, Notoclinops segmentatus, Forsterygion lapillum, Forsterygion varium and Ruanoho whero showed a high similarity in distribution, irrespective of depth or habitat characteristics. The distributions of Bellapiscis lesleyae, Cryptichthys jojettae and Ruanoho decemdigitatus were relatively similar, being primarily confined to shallow habitats providing a high degree of shelter. Forsterygion flavonigrum, Forsterygion malcolmi and Notoclinops caerulepunctus were all predominantly found beyond 10 m, irrespective of habitat characteristics. Despite the majority of species using several distinct fine-scale habitats, a high degree of variation was apparent between species, with the majority of species showing extremely low overlap of fine-scale habitats used. Differences in fine-scale habitat use were not apparent when comparing the nesting sites of species. All nests were found in fine-scale habitats, presumably affording a high degree of shelter from predation and physical disturbance. Interspecific partitioning of spatial resources probably occurs by depth and microhabitat in this species assemblage in north-eastern New Zealand.