New Zealand Journal of Marine and Freshwater Research abstracts
Induced spawning and early ontogeny of New Zealand freshwater eels (Anguilla
dieffenbachii and A. australis)
P. MARK LOKMAN
GRAHAM YOUNG
Department of Zoology
University of Otago
P. O. Box 56
Dunedin, New Zealand
email: mark.lokman@stonebow.otago.ac.nz
Abstract Knowledge on the reproductive biology of New Zealand
freshwater eels (
Anguilla australis Richardson and
A. dieffenbachii
Gray) is limited to changes associated with gametogenesis in the adults;
details pertaining to embryonic and larval development are not available, but
are of obvious benefit for a better understanding of the eel life history and
for artificial propagation programmes, whether for aquaculture or conservation
purposes. Therefore, eels were artificially matured and eggs fertilised with
sperm from either species to investigate early ontogeny. Only eggs from
A.
australis hatched successfully after c. 45 h of incubation at room
temperature, yielding larvae of c. 2.5 mm in length. Larvae survived
for up to 5 days, by which time they had attained a length of 5.3 mm.
Scanning electron microscopy of 1- and 2-day-old larvae revealed the presence
of prominent free neuromasts on the head and along the flanks. Although
hatching of New Zealand eels was achieved for the first time, it is strongly
recommended that hormone treatment be initiated immediately following capture,
well before ovarian atresia starts.
Keywords induced spawning; Anguilla spp.; eel; New
Zealand; fertilisation; hatching
M99002
Received 18 January 1999; accepted 15 September 1999
PDF file of entire paper: medium quality (2644K); (scanned from paper original: notes about this process)
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