Direct and indirect impacts from fishing gear Increasingly efficient fishing methods have a significant effect on many species. Changes include vessel engine power, size of gear and vessel characteristics, advances in navigation and fish-locat- ing devices, and the development of fixed-gear fisheries that tar- get the breeding class of several long-lived species in areas not effectively trawled in the past. All of these changes contribute to the decline of fish stocks (UNEP/MAP 2012 and UNEP/MAP/ MED POL 2005). In addition, as fleets are modernised for longer voyages and navigation through rough seas, increased pressures can be expected on species in the open ocean and in deep wa- ters (UNEP/MAP 2012).
The selection of gear type affects both species and habitats. Non-selective fishing gear, such as “tonailles” – nets used for tuna – longlines, driftnets, fine-mesh nets and trawling, are the most harmful (UNEP/MAP 2012). Although driftnets have been banned in the Mediterranean, they are still in use (UNEP/ MAP 2012). Ghost fishing – when lost or abandoned fishing gear continues to catch fish and other animals – is also a prob- lem, most commonly with passive gear (e.g., longlines, gill nets, traps). The lost gear is a threat to marine species and a danger to passing boats if it becomes entangled in their propellers or in their own fishing gear.
Trawling is particularly destructive to benthic communities. It severely alters deepwater coral ecosystems and sea grass meadows and their associated fauna, reducing both the num- ber of species and available habitat (UNEP/MAP 2012; Abdul Malak et al. 2011). Seamounts are particularly sensitive to fish- ing impacts due to their isolation and limited geographic dis- tribution (UNEP/MAP 2012). Regulations limit the use of towed gear at depths greater than 50 m or at distances greater than 3 miles from the coast if the depth is less than 50 m. Despite the regulations, however, illegal trawl fisheries are still widespread (UNEP/MAP/MED POL 2005).
Using dynamite and poison to fish is illegal, but it is still practised in some regions (UNEP/MAP 2012). These non-selective tech- niques kill many non-target species and have significant nega- tive impacts on entire ecosystems (UNEP/MAP 2012).
Artisanal fisheries, aquaculture and mariculture
The Food and Agriculture Organization defines artisanal fisheries as “traditional fisheries involving fishing households (as opposed to commercial companies), using relatively small amount of cap- ital and energy, relatively small fishing vessels (if any), making short fishing trips, close to shore, mainly for local consumption. Artisanal fisheries can be subsistence or commercial fisheries, providing for local consumption or export” (FAO/FD 2010). Ar-
HUMAN PRESSURE, STATE AND IMPACTS ON MEDITERRANEAN ECOSYSTEMS