Settlement, early growth and survival of Haliotis rubra in response to different algal species
S. Daume, A. Krsinich, S. Farrell, M. Gervis-2000
Journal of Applied Phycology, 12 (3-5) : 479-488
(from Current Contents)
Abstract :
Five diatom species were isolated from settlement
plates at Southern Ocean Mariculture, Victoria, Australia (Navicula sp.,
Navicula jeffreyi, Cylindrotheca closterium, Cocconeis sp., Amphora sp.) and
tested in settlement experiments with Haliotis rubra larvae. Settlement was
very low on single species diatom films and varied between 1%-6%. Depending
on the species combination larvae preferred to settle on films with mixed
diatom species than single species films. The highest settlement was
achieved with a mixed film of Navicula sp. and Amphora sp. Five and
ten-day-old germlings of Sporolithon durum induced settlement of the abalone
Haliotis rubra. However, the settlement rate was significantly lower on
germlings than on the whole thallus of the alga. Germlings inoculated with
the diatom Navicula sp. induced higher settlement than films of the diatom
species alone. High settlement of up to 52% was also achieved with germlings
of the green alga Ulvella lens. Settlement was reduced on U. lens squares
inoculated with the diatom Navicula sp. but higher than on films of the
diatom alone. The settlement rate was higher if plates with U. lens were
previously grazed by juvenile abalone. Post-larval growth rates were higher
on monospecific diatom films than on U. lens or on S. durum. The best growth
rate was obtained with Navicula sp. U. lens and S. durum are both good
settlement inducers, but are not sufficient to support rapid growth of young
H. rubra post-larvae. Survival was low on U. lens and on the diatom C.
closterium. We suggest that commercial nursery plates seeded with U. lens
will result in high and consistent settlement, while an inoculum with
Navicula sp. will ensure sufficient food for rapid growth of the
post-larvae.
(Deakin Univ, Sch Ecol & Environm, POB 423,
Warrnambool, Vic 3280, Australia, e-mail: sdaume@deakin.edu.au)