Census survey approach to quantifying īnanga spawning habitat for conservation and management.

Here, we describe a methodology for quantifying the spawning habitat of īnanga (<italic>Galaxias maculatus</italic>), a protected native fish species. Our approach is demonstrated with a survey of the Heathcote/Ōpāwaho following the Canterbury earthquakes that produced unexpected findings. Spawning habitat was detected over a 2.5 km reach and the area occupied by spawning sites (75m2) was much larger than in previous records (ca. 21m2). Sites dominated by the invasive <italic>Phalaris arundinaceae</italic> were found to support high egg numbers. Spawning has not previously been recorded on this species and it is identified in the literature as a threat to spawning habitat. Considerable spatio-temporal variation was also detected in the location of spawning sites and pattern of egg production. Together, these aspects illustrate the need for a comprehensive survey methodology to reliably quantify spawning habitat. The Heathcote/Ōpāwaho example shows the utility of our census approach for achieving this, and supporting habitat conservation objectives. [ABSTRACT FROM AUTHOR]