Impacts /Interactions for Recreational fisheries

Mediterranean fisheries are facing serious challenges: roughly 80% of all assessed stocks are fished outside safe biological limits, and catches are decreasing and professional fleets shrinking across the region. Recreational fisheries can exacerbate this situation in a number of ways.

Increasing fishing effort and its impact on fish stocks

Recreational fishing has been shown to be an important component of fishing mortality across the globe. Failing to include recreational catch estimates in stock assessments can undermine their accuracy and lead to incorrect advice on fisheries management. 
Comprehensive data is lacking, but the EU broadly estimates that recreational fishing represents more than 10% of the total production of all fishing. Illegal fishing also adds extra pressure on fishery resources – this is a problem in most coastal areas and MPAs. 

Impact on vulnerable fish species

Overall, vulnerable species make up nearly 20% of the total recreational catch in coastal waters (including MPAs) of the western Mediterranean. Some recreational fishing methods (e.g. spearfishing,  jigging and trolling) target species – mostly larger individuals  with a high economic value – that are also exploited by artisanal fisheries.  Many of these species – e.g. grouper (E. marginatus), red scorpionfish (S. scrofa) and common pandora (P. erythrinus) – are endangered, and are included in international conventions (e.g. Barcelona, Bern or Washington conventions), laws (e.g. EU Habitats Directive) or lists (e.g. the IUCN Red List). 
There are other environmental impacts associated with recreational fishing:
-  Disruption of trophic chains: Some fish species targeted by recreational fishers are regulative species among marine ecosystems and help control the proliferation of other species, such as sea urchins.
-  Catch-and-release and fish welfare: Certain handling techniques can cause great stress and subsequent death among fish.
-  Potential introduction of exotic species used as bait: The bait market offers several species that have been produced or harvested in other parts of the world. The use of living exotic species as bait by recreational fishers in the Mediterranean is common. Living material can displace endemic species, changing the structure of the trophic chain.
-  Potential environmental impacts of fishing gear lost or abandoned at sea: Lines and nets can remain in the water column as litter and on the seabed for many years still capturing fish, particularly in rocky habitats, resulting in additional mortality of both target and non-target species as well as abrasive action on soft and hard habitats. 
-  Damage to sensitive habitats: Three negative phenomena are observed: 1) Shellfish collectors and shore anglers trampling on the rocks – this may be partly responsible for the disappearance of a number of Cystoseira species in coastal areas. 2) Unintended contact of spearfishers with sessile organisms – inexperienced spearfishers, in particular, tend to come into contact more frequently with coralligenous assemblages. 3) Anchoring on Posidonia meadows – conventional mooring chains scrub the substrate, and can destroy the immediate environment.

More info:
Final recommendations of the PHAROS4MPAs project regarding the recreational fisheries sector in the Mediterranean.