2 Dive Sampling Programmes

Dive surveys cover a very wide range of survey designs. The main types of dive surveys covered by this database involve the collection of fish lengths using a variety of survey methods. The main types of survey method represented in this database are:

1. Random dive surveys. The area of interest is divided into sites (often 200m by 200m squares) and allocated a number. Sites are then selected at random. At each selected site, all specimens of the target species in the site are counted and a sample taken to the surface for measuring individual lengths.

2. Fish aggregation surveys. Divers count and estimate sizes of individual target species by eye. Dives are either done on: known aggregations of the target species, e.g., crayfish; random sites; or transects. In some cases, all specimens of the target species within a defined area are caught and brought to the surface for length measurements.

3. Transect dive Surveys. Divers follow a transect line for a set time or distance. For finfish target species, counts and length estimates are made by eye. For other target species, divers may search along a transect using a square quadrat end-on-end. In such cases, counts of abundance of the target species are made, and include a sample taken to surface for measuring. Transects may be pre-defined or random. During random transect dive surveys, at randomly selected sites within a defined area, divers descend to a randomly chosen depth. Beginning in a randomly chosen direction, divers measure and record the occurrence of the target species within a quadrat.

To date, species involved in these surveys include blackfoot paua (Haliotis iris), Yellowfoot paua (H. australis), kina (Evechinus chloroticus), red rock lobsters (Jasus edwardsii), and blue cod (Parapercis colias).