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This document provides an introduction to the fish ageing database age, and is a part of the database documentation series produced by NIWA.
Currently, otoliths represent the primary source of ageing material in Marine Research. Other ageing materials; e.g., scales, vertebrae, teeth, spines and statolith are rarely taken. Ageing data are derived from four main sources:
- The Scientific Observer Programme (SOP) provides otoliths from catch sampling, principally for hoki, southern blue whiting, hake, and up until early in the 1992-93 fishing season orange roughy. Additional high priority species include gemfish, ling, stargazers, red cod, jack mackerels, and silver warehou. Many other middle depth species are also sampled to a lesser extent.
- The Stock Monitoring Programme (SMP) provides ageing material by market sampling. Primarily hoki, red cod, and orange roughy otoliths were collected, with some black cardinalfish also sampled. Additionally kahawai and jack mackerels are also sampled. Orange roughy and black cardinalfish market samples ceased in the 1991-92 sample year, and red cod in the 1992-93 sample year. Recently snapper otoliths have been obtained through market sampling.
- Research voyages provide an ongoing source of otoliths. These voyages cover a wide range of species including hoki, orange roughy, black and smooth oreos, hake, ling, red cod, and southern blue whiting. A large number of inshore species are also sampled.
- Historic catch and market sampling data and ageing programmes are now becoming established on the age database. Age data for bluenose and alfonsino caught through the 1980's and data for snapper caught in the 1970's are on the age database.
To date several species have been read, including, hoki, hake, southern blue whiting, ling, red cod, kahawai, gemfish, silver warehou, elephantfish, freshwater eels and snapper. Some species; e.g., orange roughy and smooth oreo are currently catalogued and stored pending the development of a validated reading method. All otoliths gathered, irrespective of their priority, are inventoried and then catalogued, with a brief description of their location and status.
Access to information contained within the age database can be requested using the RDM@maf.govt.nz mailbox.