Sandfish hatchery techniques - English version - ACIAR

Doliolaria larvae
Main features:
h Dark-brown, barrel-shaped larvae with 5 ciliated
bands around body
h Rapid changes occur inside the body and all adult
features begin to form
h Larvae with 5 hyaline spheres on each side
h Diameter of hyaline spheres: 60–80 µm
h Short transitional phase with decreasing size
before metamorphosis and settlement
h Fast moving
Duration of this stage: 2–3 days
Pelagic and non-feeding larvae
Size range: 420–620 µm
Figure 31. Doliolaria larva.
Pentactula larvae
Main features:
h Dark tubular-shaped larvae with 5 tentacles at
the anterior end and a single posterior foot (for
locomotion)
h Rapid and differential growth
h Moving and crawling over the edge and bottom of
tank, and settlement surfaces (e.g. diatom plates)
Duration of this stage: variable
Benthic, crawling and feeding larvae
(feed on benthic diatoms)
Size range: 330–750 µm
Figure 32. Pentactula larva.
Juveniles
Main features:
h Same shape as adult but with two long tube feet
at the posterior end for early juveniles
h Slow moving and strongly attached to settlement
substrata
h Growth to 4–5 mm in 1 week
Settled and feeding stage (feed on benthic algae and
detritus)
Average initial size: 1 mm
Figure 33. Juvenile.
LARvAL REARiNG
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