Age, growth, and maturity of four New Zealand rattail species / D. Stevens ... [et al.].

Bibliographic references (p. 37-39)

Age, growth, maturity, and biomass trends of four rattail bycatch species, two saddle rattail, Coelorinchus biclinozonalis, Bollonsgass rattail, C. bollonsi, javelinfish, Lepidorhynchus denticulatus, and ridge-scaled rattail, Macrourus carinatus, were studied. Bollonsgass rattail and javelinfish are widespread in New Zealand in depths from about 250 m to 700 and 1200 m respectively. Two saddle rattails are found in the North and South Island and northwest Chatham Rise from 5 to about 500 m depths, and the ridge-scaled rattail is found from about North Cape south from 600 to 1200 m depths. All four species were difficult to age and both within-reader and between-reader agreement was generally low. Maximum observed age estimates were 15 years for two saddle rattail, 24 years for Bollonsgass rattail, 13 years for javelinfish, and 42 years for ridge-scaled rattail. Chapman-Robson estimates of total mortality were 0.54, 0.41, 0.51, and 0.15 respectively. Preliminary estimates of female length and age at first maturity were made from a limited set of gonad staging data. Length and age at first maturity based on weighted data are as follows: two saddle rattail matures at about 31 cm and 2 years of age; Bollonsgass rattail at about 34 cm and 3 years of age; javelinfish at about 35 cm and 3 years of age; and female ridge-scaled rattail at about 56 cm and 11 years of age.

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