Migratory speed and pattern of Littorina scabra on mangrove trees Sonneratia alba during incoming and outgoing tides in Tanjung Tiram, Ambon Bay

Abstract

Migratory behaviour in Littorina scabra (Linne 1758) was studied in a mangrove ecosystem and observations were made in their natural habitat or in situ observation in Tanjung Tiram, Ambon. Migratory speed and pattern of L. scabra of different sizes (small and large) particularly in mangrove Sonneratia alba were observed throughout of the February 19th to March 11th 2019 during the day and night on incoming or outgoing tides and these are usually a 3 hours (270 minutes) observation. Marked snails were used to track the position to investigate their migratory direction and speed during advancing and receding tides. Those organisms migrate up and down the trees following the tidal cycles. This study indicates that small size organisms which live on leaves, branches or trunks move faster than the big organisms and they move faster during the incoming tide than outgoing tide. For a big size L. scabra, they move slower during the incoming tide than the outgoing tide. This behaviour indicates that they move faster to avoid immersion during incoming tide than during the outgoing tide when they move slower because they are searching for food. The migration trials showed different patterns for all sizes of L. scabra and this pattern seems to be influenced by the area of surface they occupy such as leaves, branches or trunks. They tend to move forward in one direction (almost straight line) when they are on a small surface such as trunks and on the larger surface such as leaves and braches most L. scabra of all sizes make different trial patterns such zig-zag.