Measurement of abundance of 0+ snapper in SNA 8

Project: Measurement of abundance of 0+ snapper in SNA 8
Project Code: SNA2004/06
Start Date: 1 October 2004
Completion Date: 31 July 2005
Vessel Use: None

Overall Objectives:

1. To provide a time series of abundance indices of 0+ snapper (Pagrus auratus) in SNA 8.

Specific Objectives:

1. To design a survey to estimate the abundance of 0+ snapper in the main west coast harbours.
2. To quantify the relationship between 0+ snapper abundance and habitat in the main west coast harbours.

Note:

The duration of this project will be 10 months, 1 October 2004 to 31 July 2005, so that the results can be reported back to the Snapper Fishery Assessment Working Group before the research planning round in 2005.

Rationale:

General

The snapper fishery is New Zealand’s largest inshore finfish fishery by value. SNA 8 is the second largest snapper fishery with a current TACC of 1500 t. Snapper also form important fisheries for Maori and recreational fishers, but the annual catch is not known reliably. This stock is now dominated by relatively young fish, which makes the prediction of future recruitment important for management.

In the current stock assessment model, yearly recruitment indices are estimated using trawl survey indices and catch at age data sampled from the commercial fisheries. Previous trawl surveys on the west coast have been designed to measure the abundance of 2+ and 3+ snapper. As the snapper recruit at age 3 this limits the predictive power of the stock assessment in terms of providing useful management advice.

Recent work (FRST programme “Fish usage of estuarine and coastal habitats”) has shown that west coast harbours support high numbers of 0+ snapper, and are likely to be the principal nursery grounds for the SNA 8 stock. The development of a time series of recruitment indices for 0+ snapper will allow better prediction of future biomass for management of SNA 8.

The aim of this objective is to design a survey to measure the abundance of 0+ snapper in the main west coast harbours. Surveys will be stratified on the basis of habitat type and 0+ abundance from previous results.

Objective 2

The aim of this objective is to determine the importance of habitat in the west coast harbours for snapper 0+ abundance. The relative importance of each sampled harbour will be determined based on density of juvenile snapper and areas of suitable habitat.

Strategic Relevance

All the objectives in this project are consistent with the Fisheries Resources goal in the Ministry of Fisheries Strategic Research Directions document.

Cost Recovery Information:

The percentage allocation for this project will be attributed to the following Fishstock according to rule 9.1 of the Fisheries (Cost Recovery) Rules 2001:

• SNA 8

The project is estimated to cost between $0 — $50,000.