Diet composition, feed preferences and mouth morphology of early stage silver therapon (Leiopotherapon plumbeus, Kner 1864) larvae reared in outdoor tanks
2015
Aya, F. A. | Corpuz, M. N. C. | Garcia, L. M. B.
This study examined the diet composition, feeding preferences, and mouth morphology of the silver therapon (Leiopotherapon plumbeus, Kner 1864) larvae under captive conditions. Larvae were reared in outdoor tanks (4 m³) with natural food grown 2 weeks prior to start of larval rearing. Food preference was measured by the Chesson's electivity index (αᵢ). Gut content analysis of larvae sampled between 5 and 25 days after hatching (DAH) showed the dominance in the diet by zooplankton, mainly copepod nauplii, cladocerans and insect larvae. Small fish larvae (5–9 DAH; 3.32–6.29 mm standard length) preferred cladocerans, ciliates and copepod nauplii; whereas older larvae (12–25 DAH; 5.45–19.26 mm standard length) preferred insect larvae over cladocerans and adult insects. The mouth gape size at 5 DAH was 359 μm and increased to 3.75 mm at 40 DAH when body size grew at an average rate of 0.59 mm d⁻¹. The standard length (SL) of L. plumbeus larvae was strongly associated with mouth size (r² = 0.98, P < 0.05), indicating a progressive increase of ingested prey size of the fish larvae. These results clarified the early life feeding ecology of this species, which is essential in developing effective hatchery techniques.
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