SELF OR SELFISH REGULATION, THE DILEMMA OF CLAM HARVESTING Donatella Del Piero Biology Dept. University of Trieste Italy

Wild clam harvesting is not a fascinating field or so seems: after a rapid investigation on ASFA, provided that only: 95 articles are dealing with, in respect of more than obtained with keyword “fishery”. This may be the effect of the effort devoted to aquaculture, but locally clams may be really important sources (e.g Italy, Spain.) and: the life cycles cover planktonic, meio and macro benthic phases.

Copyright Esa 2003 The area

Chamelea gallina 2.6 cm in length The species

A fishing boat Copyright: federcoopesca

From central to local governance Since the 1995, but really effective after 1997, the direct control of fishermen organized on local basis, transformed the clam fishery management in Italy The Ministry reduced the overall fleet capacity from 764 To: 665 Till 2008

This followed after near a 20 years phase of regulation year after year more severe but “de facto” never accomplished The more important fixed in 1992 the maximum daily catch at 600 Kg. Before: 2.5 metric tons was the “limit”

October-November 1996: The fishery collapsed after a mass mortality a full recovery lacked and: the recruitment was not allowed to consolidate in space or time

After that: We can say that a “moral” question arised: how can we regulate fishery if the hypothetical gain from tight rules may suffer big crises?

The fleet 19 in the Gulf of Trieste ~50 Km² Unofficial landings 2002: ~750 metric tons* 2003: ~684 metric tons* ~ 120 in the Gulf of Venice ~ 216 Km²(110) Unofficial landings 2002: 4229 metric tons 2003: 5641metric tons Source : * Fishermen Organisations and Irepa irepa.org

Present guidelines 250 Kg/pro die and 4 work-days in a week, with no compensation for losses due to bad weather (G.of Trieste) 2 months stop 320 Kg/pro die, 4 work-days (G. of Venice) Stop as above

Survey of 2002 Data obtained from surveys done in the Gulf of Venice and of Trieste in 2002 summarized in a cumulative distribution show mollusks bed at a critical point

Results from the survey The maximum depth (-6 m depth) in the Gulf of Venice is attained on 7 transects (out of 17)

Estimated age

Results from Gulf of Trieste K-S test : D max (Ve-Ts)=0,282, D 0.05 =0,018 the maximum depth was -5 m and in only one transect (out of 10)

Self regulation The reduction of daily landings for better price The self control among fishermen A partially common strategy for sales Restocking processes (doubtful)

The selfish regulation Undersized clams are common on markets The scarcity reduces incoming, so formerly excluded area are under pressure The fishermen in fact asked and obtained to fish between 2.5 and 3 m depth Next step: asking for minimum size reduction?