Distribution in scandinavian waters
|Maximum length: It is difficult finding
information about the maximum size of the trochophora larvae, but you
can compare the larva with a hair.
Appearance: Trochophora larvae are transparent and can have a round, pear or diamond shape. Around the middle or top of the body, a band of cilia is situated. Often there are several longer hairs sticking out of the top of the body and sometimes even a small tuft at the bottom. The mouth is very distinct and a simple eye is sometimes visible.
Depth: From the surface to unknown depth.
Misc: When the eggs hatch, a larva appears. During this larva stage they seldom resemble adults and furthermore, do not live the same life style. Trochophora larvae are found amongst most groups, for instance polychaetes and molluscs. When the polychaetes trochophora larvae grow, the hind areas are extended and became segmented. This larva stage is called metatrochophora. The molluscs never became segmented during this larvae stage, but cilia in a circular form develope into one or more flaps so the larvae became snail- or mussel veliger.
Trochophora larvae are most noticable during the summer, but can on occasion be seen during the winter. The time spent as pelagic larvae varies greatly between the different specie. The larve live on the nutrients provided by the egg and other small organisms found in the water. The food is caught, transported and sorted by the different cilia that are situated on the body, while other cilia are used for propulsion. A great many larvae are consumed by suspension feeders.
Classification: Trochophora larvae are found amongst certain molluscs, polychaetes and some lesser worm groups and certain bryozoas. The larva pictured above is from the Polynoidae group.