AB 26:137-148 (2017)  -  DOI: https://doi.org/10.3354/ab00679

Assessing maturity, fecundity and hermaphroditism in blue cod Parapercis colias

K. K. Brandt1,3,*, M. R. Dunn1, S. L. Brouwer

1School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand
2Oceanic Fisheries Programme, Pacific Community (SPC), BP D5, Noumea 98848, New Caledonia
3Present address: 100–104 Stoke Newington High Street, London N16 7NY, UK
*Corresponding author:

ABSTRACT: Macroscopic assessments of maturity from whole fish gonads are well established and routinely used in fisheries research and are important in the estimation of size-at-maturity and the impacts of size-selective fishing. Histological assessment of maturity is more accurate, but much slower, more expensive, and so less frequently conducted. We made a comparison between macroscopic and histological maturity classifications for a diandric protogynous hermaphrodite, blue cod Parapercis colias. The agreement between macroscopic and histological maturity classifications was low. Female and male L50 (length at which 50% of the fish are mature) was estimated from histological data as 23 and 26 cm, respectively. Female spawning frequency was 4.6 d, and mean ± SD relative batch fecundity was 6.5 ± 3.3 hydrated oocytes per gram body weight. A single gonad with both testicular and ovarian tissue was found. Many blue cod were assigned incorrect maturity classifications. These results warrant a study of early gonadal development in blue cod to elucidate if and how sex change takes place. Difficulties in determination of sex and maturity may be most pronounced for species, like blue cod, that have complex maturation patterns. For blue cod, a review of the macroscopic maturity classification key and more thorough technician training are called for.

KEY WORDS: Maturity assessment · Length at maturity · Fecundity · Parapercis colias · Sex change · Histology

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Cite this article as: Brandt KK, Dunn MR, Brouwer SL (2017) Assessing maturity, fecundity and hermaphroditism in blue cod Parapercis colias. Aquat Biol 26:137-148. https://doi.org/10.3354/ab00679

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