Pteropoda
Sampling

The tiny shells of pelagic molluscs can be found along the beach. However, they are not easily visible because of their small size, and are usually overlooked unless occurring in mass accumulations. Because the shells are very fragile only fragments are usually found.

For quantitative and biogeographic studies the most widespread collection method is by nets with a mesh size of 0.3 to 4.0 mm, although 0.05-0.2 mm mesh openings are required for retrieval of juveniles. Whenever possible opening-closing nets which collect animals from pre-determined depth intervals are preferred. Non-closing nets, however, which were used in many collections, still offer a good opportunity to study horizontal distributions. Handling nets requires special care as the shelled as well as naked species are very fragile. The tows should be of short duration to prevent damage. The net should be opened gently and cleaned of its contents with extreme care. Collecting Cymbuliidae requires special care because pseudoconchs easily detach from the soft parts. Scuba diving and sampling/observation from submersibles are modern developments which offer unique opportunities to collect the fragile animals.