Visual thresholds for feeding and optimum light intensity for larval rearing of Asian seabass, Lates calcarifer (Bloch)
This study examined the retinomotor responses and prey ingestion rates of 10-, 15-, 20- and 30-day-old Asian seabass Lates calcarifer under different light intensities from 0 to 1000 lx to determine the visual thresholds. Subsequently, two age groups of seabass larvae were reared under light in...
| Main Authors: | , |
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| Format: | Article |
| Language: | English English |
| Published: |
Wiley-Blackwell
2014
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| Subjects: | |
| Online Access: | http://irep.iium.edu.my/27860/ http://irep.iium.edu.my/27860/ http://irep.iium.edu.my/27860/ http://irep.iium.edu.my/27860/1/aquaculture_research_2012.pdf http://irep.iium.edu.my/27860/4/27860_visual%20thresholds_scopus.pdf |
| Summary: | This study examined the retinomotor responses and
prey ingestion rates of 10-, 15-, 20- and 30-day-old
Asian seabass Lates calcarifer under different light
intensities from 0 to 1000 lx to determine the visual
thresholds. Subsequently, two age groups of seabass
larvae were reared under light intensities of 10,
100 and 1000 lx to determine the optimum illumination
in hatchery tanks. Retinomotor response
was absent in 10-day-old larvae, but quite marked
in 15- and 20-day-old seabass at 1 lx and higher.
Ingestion of Artemia nauplii by 10-day-old larvae
was almost zero at <1 lx, increased significantly at
1 lx, and was maximal at 10–100 lx. Artemia
ingestion under dim light <1 lx improved with age,
and older larvae took more prey in complete darkness
due to the presence of rod cells (and also free
neuromasts). Larvae from 13 to 26 days group had
similar survival and growth at 10–1000 lx, however,
from 5 to 10 days group showed similar survival
rate with highest weight gain at 100 lx.
Therefore, we recommend that hatchery rearing
tanks be illuminated such that the larvae in the
water are exposed to approximately100 lx. |
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