Sunday, May 20, 2012
The shell that lets in light
I found several interesting species which are normally associated with a sandy sea bottom.
The Maltese islands do not have regular tides, but the sea level sometimes goes down by a few centimetres, which in places like Għadira Bay can result in a considerable retreat comparable to a tide.
When this happens one gets the chance to observe more specimens of marine flora and fauna.
The most common seashell on the beach was that of the rayed trough-shell (Mactra stultorum), which is known in Maltese as arzella tal-baħar.
This species belongs to a family of bivalve molluscs commonly known as trough shells or duck clams.
Ten members of this family are found in the Mediterranean but only four species have been recorded around the Maltese islands.
The rayed trough-shell is found in the north, from Norway down the west coast of Europe to the Iberian Peninsula and along the African coasts as far south as Senegal. It is also found along the Mediterranean and Black Sea coasts.
It lives in sandy bottoms from five to 30 metres deep and is often found cast up on beaches. It has a thin and delicate shell through which light can pass, providing one with many opportunities to create beautiful pictures especially early in the morning or late afternoon.
Like many other species of molluscs, the rayed trough-shell is edible and in some places it is collected and sold in markets.
This article was published in The Times on 7.12.11