Recruitment of Pinna nobilis (Mollusca: Bivalvia) on artificial structures

Abstract

The fan mussel Pinna nobilis is a long lived species endemic to the Mediterranean Sea and is considered one of the biggest bivalve molluscs of the Mediterranean. A multitude of threats has provoked a great reduction in P. nobilis populations. To increase the knowledge about the recruitment period and number of Pinna nobilis recruits, two types of recruitment devices were deployed in July 2007 on a Marine Protected Area of Palma Bay, Mallorca (western Mediterranean). A total of 614 juveniles of P. nobilis , with a mean length and width of 2.76±0.04 and 1.10±0.01 cm respectively, were collected inside the artificial microhabitat generated by the knots of ‘device Type I’. Similarly, 691 P. nobilis were recruited with a mean length and width of 5.38±0.08 and 2.10±0.04 cm respectively from ‘device Type II’. Moreover, in the year 2007, the present study determined that P. nobilis recruitment takes place between the last week of August and the first week of September. This study produces some crucial information for effective protection and conservation of the fan mussel. Moreover, a Pinna nobilis artificial recruitment with seed collectors would permit an alternative tool for field studies without compromising the concentration of the vulnerable populations of this mollusc.