The effect of light intensity on first feeding of the
spotted sand bass Paralabrax maculatofasciatus (Steindachner) larvae
R. Peña, S. Dumas,
R. Saldivar-Lucio, G. García, A. Trasviña, D. Hernández-Ceballos-2004
Aquaculture Research, 35(4): 345-349
Abstract:
The
effects of light intensity on feeding incidence and prey consumption at
first feeding of spotted sand bass larvae (Paralabrax maculatofasciatus
Steindachner), using four light intensity treatments (0, 100, 400, and 700 lx)
were evaluated. Specimens were fed the rotifer Brachionus plicatilis
at a density of 3 rotifers mL-1. One hour after the
addition of prey, 30±3 (mean±SEM) larvae were sampled from each treatment
aquarium. Feeding incidence was evaluated as the percentage of larvae with
prey in the digestive tract. Feeding intensity was measured as the number of
prey in the digestive tract of the larvae. Histological analysis was carried
out to describe the eye structure at the time of first feeding. Larvae fed
in darkness (0 lx) had a significantly lower (P<0.05) feeding
incidence (1.2±2.2%) and intensity (0.4±0.7 rotifers larvae-1)
than those larvae fed at 100 (28±11%, 1.8±0.2 rotifers larvae-1),
400 (48±10%, 2.4±0.3 rotifers larvae-1), and 700 lx
(52±4%, 2.4±0.1 rotifers larvae-1). Feeding incidence of
the spotted sand bass larvae increased with light intensity while the
feeding intensity showed no significant difference (P>0.05)
between light treatments. Histological analysis of the eye structure showed
that first feeding larvae had well-formed lens along with a retina composed
of pure single cones as photoreceptors.
(Unidad
Piloto de Maricultivos, Centro Interdisciplinario de Ciencias Marinas, PO
Box 592, La Paz, Baja California Sur 23096, Mexico. E-mail: blacklarvae@hotmail.com)