- Overfishing: Some species are heavily overfished, which means their populations do not have any chance to recover and are constantly depleting, for example tuna, swordfish, several shark species and many others.
This has a very negative effect on the population of the overfished species but also on the marine ecosystem by damaging its balance and function, and in this way threatening other species in the ecosystem as well
- Bycatch: Not only trawl, drift and purse seine nets but also in the longline fishery, many non-target species get caught, including sharks, dolphins, whales, rays, turtles, birds and many non-target fish species.
The worst you can go for are wild caught shrimps. Try to image the mesh size you need to catch little creatures like shrimps and then try to imagine that you are catching everything else that is bigger than that mesh size. Even consumption of fish from aquaculture is likely to be connected to bycatch, as the fishes are fed with fish meal, which mainly consists of anchovies, tiny fishes that have been caught with nets

Unwanted fish tossed back into the ocean Photo: Brian J. Skerry WWF
- Your health: Not only fish from non-organic aquaculture might contain many ingredients that you do not want in your food.
While fish from non-organic aquaculture is likely to contain heavy metals, antibiotics and organochlorines, some of them with estrogenic effects on your body, also wild caught fish, especially large predators like sharks, tuna and swordfish
- Fairtrade: Many local communities suffer of overfishing effects by large-scale industrial fisheries.
There is not much fish left for them to eat or to sell. For example the traditional swordfish fishery in Southern Italy does not cause any bycatch and is in this way very sustainable, however these fishermen do not have a chance in catching enough fish for their livelihoods if large-scale fisheries continue overfishing
- Habitat destruction: Some fishing methods physically destroy marine habitats. For example dredges are used for the scallop fishery and destroy the seabed and everything that lives on it

Scallop dredged site before and 2 days after. Photo: flyfishing.co.uk