Untitled - CNR

Fishery and Sea Resourceswhile on the other it still considers themas “special waste” (DPR 915/1982, article2, comma 4), a priori forbidding dumpingat sea. Besides the bureaucratic and administrativehassle, even the scientific communityhas diverging attitudes toward theeffects of shipwrecks, with some in favor[38, 39] and some against it [40], becauseof a precautionary approach. The majorreasons which are opposed against sinkingdecommissioned vessels and fishing boatscould easily be refuted [41], using scientificresults and plain common sense (contrastingthe widespread “Petrarch’ principle”,[42]):a) Source of pollution: a real issue for theship that sunk by accident [43], is a nostarter for deliberately sunken vessels,which undergo extensive clean up followinginternationally agreed procedures[44], taking out painting, oil, plastic material,insulation, batteries and any otherpolluting stuff.b) Dangerous for diving: of course, divingin a swimming pool could be safer. . . but wrecks remain the most soughtdestination for underwater exploration[45]; the same international proceduresrequire numerous intervention for thesafety of SCUBA divers (doors arewelded, passages are ample, holes areblocked, spikes and cutting edges arefixed or removed, and so on).c) Incompatible with MPAs: on the contrary,vessels have already be positionedon MPAs bottoms, because they deter illegalfishing (“silent policemen”), offerrefuge to sensible species, permit an ecosustainable fruition of the area.d) Risky for navigation: the preliminary“sector meeting” encompasses all theofficial stakeholders, among whom theCoast Guard; with them, suitable sitesoutside the commercial sea lanes are selected,and a minimum clearance of 15 mis guaranteed.e) Hindering the legal fishing too: it is impossibleto damage the gear involuntarily,because the shipwreck location isknown, fixed in time and space, signaledlocally with buoys and drawn on charts,thus easily avoided.f) Causing ghost fishing: apart from thefact that nets and gear should not beemployed to close to any grasping site,the fishing power of lost nets does notlast long, since they become self entangledon the metallic structures [46];moreover, diving centers working on thewreck are often voluntarily removing thegear snarled on it [47].g) Helping poaching: shipwrecks are effectivelyricher in fish than the surroundingarea, a tempting occasion for poachers.The question whether the wrecks functionvia increased production or just becausethey attract neighboring specimensis debatable [48], [49], [50]); in fact, ifthat is just a “fish concentrate”, poachingwill deplete existing resources, but recentresearch seems to corroborate the thesisof new fish biomass generation [51],[52], [17], and therefore illegal fishing onscuttled wrecks does not worsen the statusquo ante.h) Altering environment and biocoenoses:it has been shown, even on very extendedand complex artificial barriers, that geomorphologicalalterations are limited tothe very proximity of the manufacts, andthat surrounding biological communitiesare unscathered [53].i) Just too “ordinary”: in fact, even beforesinking, vessels are better than classicalconcrete barriers: cost less (ormarginally nothing), are easy to transport,can be readied without disturbingthe neighboring coast; once in water,1932