New Zealand Journal of Marine and Freshwater Research abstracts
Embryology and early larval development of orange roughy (Hoplostethus atlanticus Collett)
JOHN R. ZELDIS
National Institute of Water & Atmospheric
Research Ltd
P. O. Box 8602
Christchurch, New Zealand
PAUL J. GRIMES
ALAN C. HART
National Institute of Water & Atmospheric
Research Ltd
P. O. Box 14 901
Wellington, New Zealand
Abstract Orange roughy (Hoplostethus atlanticus
Collett) egg development is described from fertilisation in a series of 29
stages based on morphological criteria. Two early larval stages are also
described. Observations were made of eggs obtained from strip-fertilisation
using trawl-caught adults and from plankton net samples of eggs caught off the
east coast of New Zealand, and then cultured on-board ship. Live eggs of each
stage are described and illustrated with line drawings and photographs and
age-at-stage data are presented. The mean development times from fertilisation
to hatching were 278 h at 8deg.C, 235 h at 10deg.C, and 146 h at 12deg.C. Eggs
cultured at 6deg.C did not hatch. The mean length of the larvae at hatching was
5.33 mm notochord length. Most criteria used in staging are readily observable
with a standard dissecting microscope at x25 magnification using transmitted
light. Damaged eggs are common in egg production surveys for orange roughy. The
staging of damaged eggs is described. Orange roughy eggs can be sorted easily
from plankton samples collected during egg production surveys for orange roughy
biomass, and staged on-board ship before preservation.
Keywords orange roughy; egg development; larval development;
egg production surveys; New Zealand
New Zealand Journal of Marine and Freshwater Research, 1998, Vol. 32:
159-174
0028-8330/98/3201-0159 $7.00/0 (c) The Royal Society of New Zealand
1998
PDF file of entire paper: medium quality (2290K); (scanned from paper original: notes about this process)
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