Shellfish Breeding and Hatchery Management (2+1)

7.2.4 Larvae of Lobster

The size of this larvae is very large, having head, throax, abdominal regions, and is transparent as glass. A large carapace covers the first two thoracic segments and head. Abdomen is very much reduced and may be indistinctly segmented, but without appendages, the antennae and maxillae are degenerated before hatching. The seventh and eight thoracic appendages and abdominal somites are not clearly segmented in the larvae, even though they are well defined in the embryo. The first thoracic appendages are rudimentary and second is uniramous.

The Phyllosoma undergoes several moults before becoming an young lobster(juvenile) and duration of this stage may extend upto 250 days (90-250 days). There are 7-13 Phyllosoma stages(some times a pre-Phyllosoma, and pro Phyllosoma). The larval periods of palinurids ranging from few months to almost 2years before last Phyllosoma stage at about 35 mm in length.

Puerulus stage (7-56 days,I - stage)

After 6-10 months in the planktonic larval stage, the Phylllosoma larva metamorphoses into the Puerulus stage.

It is transparent, free swimming, non feeding post larval stage that moves inshore where it settles to the bottom. Subsequently through ecdysis, Puerulus becomes juvenile lobster which leads a nectonic swimming life with well developed appendages.