Exploitation of fish and shellfish Fisheries are the greatest users of marine resources in the Medi- terranean. Commercial fishing tends to be concentrated in in- shore areas, although there are fisheries for pink shrimp (Penaeus duorarum), deepwater rose shrimp (Parapenaeus longirostris), and hake (Merluccius merluccius) on the continental slope (UNEP/ MAP 2009). Total fish landings increased exponentially from 1950 to 1980, with current production fluctuating around 800.000 tonnes annually (Garcia 2011) during the last three decades. Of that total, 85 % comes from six countries: Italy, Turkey, Greece, Spain, Tunisia and Algeria (UNEP/MAP 2012).
Mediterranean fisheries are primarily coastal. The abundance and distribution of exploited species in coastal waters vary ac- cording to depth, with the continental shelf being the most pro- ductive area. The shelf extends from the coast to a depth of ap- proximately 250 m. Fisheries in this region are highly diversified, although non-industrial fishing from small boats – less than 15 m long – dominates (UNEP/MAP 2009). The entire Mediterranean fishing fleet was estimated at 85.000 boats in 2008 but the real number is likely much higher (Sacchi 2011).
Reproductive capacity of stocks
Many fish species in the Mediterranean are over-exploited as a result of growing pressure from both commercial and recrea- tional fisheries (UNEP/MAP 2012). In the Mediterranean over- all bottom-feeding stocks are dominated by juveniles, which could indicate high fishing pressure (EEA and UNEP 2006). The overfishing of juveniles can lead to changes in population structure, which ultimately affects the sustainability and recov- ery of stocks (UNEP/MAP 2012). Some species also have life cy- cles that make them more vulnerable to over-exploitation, such as slow growth rates and older age of maturity.
Fisheries tend to target larger, more valuable species higher in the food web. As the numbers of higher predators decrease
The main species of fish exploited in the coastal areas are sardine (Sardina pilchardus) and anchovy (Engraulis encrasi- cholus) among the small pelagics, and hake (Merluccius mer- luccius), mullet (Mullus spp.), whiting (Micromesistius pouta- sou), angler fishes (Lophius spp.), sea bream (Pagellus spp.), octopus (Octopus spp.), squid (Loligo spp.), and red shrimp (Aristeus antennatus) among the demersals, and big pelagics like bluefin tuna (Thunnus thynnus) and swordfish (Xiphias gladius). Landings of these species represent 70–80 % of the total fish landings in the Mediterranean. Invertebrates are also exploited, including red coral (Corallium rubrum), many sponge species (Spongia spp., Hypospongia spp.), and natu- ral beds of bivalves (Lithophaga lithophaga, Acanthocardia spp., Callista chione, etc.) (UNEP/MAP 2012).
due to over-exploitation, species further down the food web start to dominate the catch. This is known as “fishing down the food web”. This process appears to have been taking place in the Mediterranean at least since the mid-20th century (Pauly et al. 1998).
Key issues in Mediterranean fisheries
Overexploitation Over-exploitation of fish stocks is reported across the Mediter- ranean. More than 65 % of commercial stocks are fished beyond sustainable limits (UNEP/MAP 2012; Abdul Malak et al. 2011). Although commercial fisheries have the greatest impact, recrea- tional fishing also places pressure on stocks. Some species, such as Atlantic bluefin tuna (Thunnus thynnus) and dusky grouper (Epinephelus marginatus), have been fished to such an extent that they are both listed as Endangered on the IUCN’s Red List (Abdul Malak et al. 2011). Both croaker (Sciaena umbra) and shi drum (Umbrina cirrosa) have been listed as Vulnerable, while Eu- ropean plaice (Pleuronectes platessa), Baltic flounder (Platichthys flesus), European seabass (Dicentrarchus labrax), white grouper (Epinephelus aeneus), swordfish (Xiphias gladius), Atlantic chub mackerel (Scomber colias), and turbot (Psetta maxima) are listed as Near Threatened (Abdul Malak et al. 2011). Of the 86 shark, ray, and chimaera species in the Mediterranean, fifteen are Criti- cally Endangered, nine are Endangered, and eight are Vulnerable (Abdul Malak et al. 2011). Another ten species are listed as Near Threatened (Abdul Malak et al. 2011). Recovery of many stocks has been hindered by factors other than fishing, such as pollu- tion and increasing water temperature.
By catch By catch – the accidental capture of non-target species in fish- eries – is a serious issue in many parts of the Mediterranean. Species not eaten by humans are discarded overboard. Glob- ally, one-quarter to one-fifth of all fish caught is thrown over- board (CMS [no date]). While some of the discards may be eaten by opportunistic ocean feeders, most are wasted (UNEP/MAP 2012). Longlines and driftnets result in significant by catch of sea turtles, marine mammals (especially whales and dolphins), seabirds, and sharks (Abdul Malak et al. 2011).
58 STATE OF THE MEDITERRANEAN MARINE AND COASTAL ENVIRONMENT