The influence of habitat availability and adult density on non-diadromous galaxiid fry settlement in New Zealand
Authors: Jellyman; McIntosh
Source: Journal of Fish Biology, Volume 72, Number 1, January 2008 , pp. 143-156(14)
Abstract:This study investigated factors controlling settlement and initial density of two species, Galaxias vulgaris and Galaxias paucispondylus (Galaxiidae), in New Zealand streams. Factors affecting maximum fry abundance were assessed at 10 sites (eight streams) differing in habitat characteristics and the presence or absence of introduced brown Salmo trutta and rainbow trout Oncorhynchus mykiss. Regression analysis indicated that conspecific adult numbers, extent of backwater habitat and brown and rainbow trout density were the most important factors determining initial fry density. Experimental additions of backwater habitat increased fry settlement tenfold compared with control reaches, demonstrating that the area available for fry settlement had a substantial effect on fry abundance. Results from this study indicate that fry settlement may be a critical limiting phase for some non-diadromous galaxiid populations. Increasing settlement area to enhance fry retention offers a practical conservation tool for fisheries managers that may aid conservation of threatened fishes like galaxiids.
Document Type: Regular Paper
Affiliations: School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
Publication date: January 1, 2008