Impacts /Interactions for Small-scale fisheries

At a global scale, SSF support livelihoods in coastal communities and contribute significantly to food security, especially in developing countries. The same is true in the Mediterranean basin, especially in countries with high numbers of small-scale fishers. Despite accounting for only 26% of overall fishery revenue, SSF account for around 59% of all onboard employment in the Mediterranean, a total of some 134,300 jobs, and they represent 80% of the Mediterranean fleet, with some 60,000 vessels. These brought in USD 519 million (24%) of the region’s commercial fishing revenue in 2017.
Despite the fact that the volume of SSF catches are relatively low compared to large-scale commercial fisheries, SSF still have the potential to impact fishing resources and marine ecosystems. While other factors – including climate change, pollution from marine and terrestrial sources and catches from recreational fishers – also contribute to the decline of fish resources, SSF can cause serious impacts when, for example, the fishing effort is very high. Yet they are generally considered to have less ecological impact than industrial fisheries, and are usually seen as more sustainable. 

Potential impacts include: 
-    Altering biodiversity and changing ecosystem functioning by removing key species (e.g. top predators) or specific size classes. Key species are regulative species which help control the proliferation of other species; while larger females have more offspring, reproduce over a longer period and spawn bigger eggs and larvae with better survival rates than smaller females.
-    Targeting species that are classed as vulnerable on the IUCN Red List. In a study carried out in France, Italy and Spain, nearly 50% of the total SSF catch in coastal waters – and 100% in offshore waters – was of vulnerable species.  
-    Size-selective fishing affecting hermaphrodite fish species, such as dusky grouper (Epinephelus marginatus), which can make up a significant portion of the catch. Fishing may disproportionately remove members of one or other sex, altering sex ratios and leading to egg or sperm limitation.
-    Catches below the minimum landing size prevent individuals from reaching maturity and reproducing. There is growing concern that levels of fishing mortality as a result of bycatch and discards threaten the long-term sustainability of many fisheries and the maintenance of biodiversity in many areas. 
-    Habitat degradation with direct and indirect action. Specific fishing techniques (e.g. small-scale dredges) and anchoring destroy or erode vulnerable habitats including seagrass meadows (Posidonia oceanica), coralligenous reef assemblages and deep rocky habitats that contain sessile and fragile organisms such as gorgonians, sponges and corals. 
-    Lost or abandoned fishing gear – such as nets, hooks and lines – also causes harm. So-called ghost gear continues to catch fish, and gear of all kinds can abrade sessile animals like corals and gorgonians. It also represents a significant fraction of marine litter. Oil and antifouling paints are other notable sources of pollution.

Impacts on endangered, threatened or protected species 
Marine mammals are mostly impacted by polyvalent vessels when they’re caught in nets. Small vessels using set nets, demersal longlines or pelagic longlines make up most of the Mediterranean fleet, and likely cause more incidental or intentional deaths of marine turtles than large vessels typically using bottom trawls or pelagic longlines. The total annual bycatch of marine turtles in the Mediterranean is estimated at up to 132,000 individuals, resulting in a potential annual mortality of 44,000. Gillnet, trammel net, longline and bottom trawl fisheries are considered a major threat to the survival of elasmobranch (sharks and rays) populations in the Mediterranean and the Black Sea. Seabird populations are mainly impacted by longliners, while fishing on longliners’ baits.