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Analysis of growth and first reproduction of hatchery-reared juvenile Cortez oyster (Crassostrea corteziensis) in northwestern Mexico: Proposal of a minimal fishing size

Abstract:

This study presents complimentary data of early growth and age/size of first reproduction of hatchery-reared Crassostrea corteziensis juveniles cultivated in the field for 9 months. Samples of oysters and gonads were collected monthly to determine absolute growth and growth rates, as well as overall gonad development. At the end, adult oysters ranging 75.6 ± 0.62mm shell height (SH) yielded a mean growth rate of 0.308mmday -1, which is among the highest reported for the species. Gametogenesis began in March-April and spawning occurred during August and September. Males outnumbered females at smaller sizes, but female were more abundant at larger sizes. From planting time in the field, the age/size of first maturity was 3.25 months for males (42mm SH) and 4.5 months for females (54mm SH), with a mean population age of 4.75 months for males (size range 55-59mm) and 5.25 months for females (60-64mm). Based on these results, and the time needed for hatchery care prior planting juveniles in the field (2.25 months), we propose limiting fishing of wild oysters to sizes >65mm height to allow them to breed at least once and contribute to restoring wild populations. © 2011 Blackwell Publishing Ltd.