Fig. 9

Population trends in the Argentinean surf clam M. mactroides: mean abundances from the present study (1: 2005; 2: 2006) compared with historical records (3: Coscarón 1959; 4: Olivier et al. 1971; 5: Bastida et al. 1991; 6: Mabragaña 1997) and landing data (histogram: Coscarón 1959). Ⓐ indicates mass mortality of M. mactroides in South America (in March 1993: Odebrecht et al. 1995), Ⓑ and Ⓒ unexplained mass mortality events in Argentina (in November 1995: Fiori and Cazzaniga 1999; in September 2004: Thompson and Sánchez de Bock 2007, respectively). Grey area shows the period when M. mactroides was commercially fished, the white area is the period when the clam fishery was closed