New Zealand Journal of Marine and Freshwater Research abstracts

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Hormone-induced maturation in male New Zealand freshwater eels (Anguilla spp.)

P. R. TODD*

Marine Laboratory Department of Zoology Victoria University of Wellington Private Bag Wellington, New Zealand

Abstract Male adult Anguilla australis and A. dieffenbachii caught migrating to sea were held in sea water and induced to mature with injections of human chorionic gonadotrophin. Eye size increased during maturation by a factor of 1.5 in A. australis and 1.2 in A. dieffenbachii from the pre-injection migrant stage. Spawning was observed in 4 of the 42 eels that matured. A. australis matured at between 12 and 28°C and A. dieffenbachii between 12 and 26°C. Minimum maturation times occurred at 26°C for A. australis and 24°C for A. dieffenbachii. Maturation rate and temperature were linearly related in both species. A. dieffenbachii matured more quickly than A. australis at all temperatures; this is probably related to the different state of sexual development of the experimental eels. At the time of seaward migration A. dieffenbachii are more sexually advanced than A. australis.

Keywords Anguilla australis; Anguilla dieffenbachii; hormones; sexual maturity; maturation; temperature.

New Zealand Journal of Marine and Freshwater Research, 1981, Vol. 15 : 237-246 Received 21 May 1981

PDF file of entire paper: medium quality (2622K); (scanned from paper original: notes about this process)

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