Validation of growth zones in stargazer otoliths

Project: Validation of growth zones in stargazer otoliths
Project Code: STA2004/03
Start Date: 1 October 2004
Completion Date: 30 September 2006
Vessel Use: Subject to tender

Overall Objective:

1. To validate growth zones in stargazer (Kathetostoma giganteum) otoliths.

Specific Objectives:

1. To validate growth zones in stargazer otoliths using chemical markers.

Rationale:

General

Giant stargazer, Kathetostoma giganteum, support moderate value, moderate volume fisheries around the South Island. It is presently managed as eight separate stocks, with STA 3, 5, and 7 surrounding the South Island. Furthermore, STA 3 and 7 are managed under the conditions of the Adaptive Management Programme (AMP).

Four studies have been carried out on the age and growth of giant stargazer around the South Island (Table 1). Stargazer otoliths are, however, difficult to read and the protocol used for interpreting them (Sutton 1999) is yet to be validated. Given the immanent stock assessment for STA 7, validation of stargazer growth zones is important.

Table 1: Studies on the age and growth of giant stargazer carried out to date.

Objective 1

Although an otolith margin analysis was carried out by Sutton (1999), the results were inconclusive. A chemical marking experiment is therefore proposed to investigate directly, the annual nature of stargazer growth zones.

Strategic Relevance

The objective of this project is consistent with the Fisheries Resources goal and Strategic Objectives in the Ministry of Fisheries Strategic Research Directions document.

Cost Recovery Information:

The percentage allocation for this project will be attributed to the following Fishstocks according to rule 9.2 of the Fisheries (Cost Recovery) Rules 2001:

• All STA Fishstocks

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