Small ocean fish are thriving while humans eat up all their predators

«Little fish have never had it so good, according to research showing how mankind’s taste for big fish such as tuna and shark is allowing the anchovy and sardine to flourish.

Industrialised fishing practices are causing a revolution in the world’s oceans, with numbers of predator fish - which also include swordfish, grouper, North Atlantic cod and salmon - tumbling by 54 per cent in the past four decades. These fish sit at the top of the food chain and are more popular with humans than the smaller species because people find them tastier. Their volume – by weight - has fallen by 67 per cent in the past century, a University of British Columbia study has found.

But the drastic reduction in big fish in recent decades is great news for the smaller prey fish such as pilchards, herrings, sprats and caplin because it has significantly increased their chances of survival. The decline in predators has shored up supplies of once dwindling small fish - including anchovies and sardines - for decades to come.

The volume by weight of smaller fish has more than doubled in the past century. The biggest increases are to be found in those fish that are less popular with humans, such as sticklebacks and Gobies, the research found. Over the same period, the volume of predators fell by 67 per cent.

Despite the flourish small fish populations, scientists are concerned. “This should be a warning bell for the rest of the world. We are still fishing way too much,” said Professor Villy Christensen, lead author of the research paper. “Predators are important for maintaining healthy ecosystems."» (Βλ. σχετικό άρθρο..).

Πριν λίγες μέρες κάποιος με ρώτησε: «τι σημαίνει αλιευτική διαχείριση;» Δεν ξέρω τι κατάλαβε από την απάντησή μου, αλλά θα του πρότεινα να ρίξει μια ματιά στο παραπάνω άρθρο για να καταλάβει το τι ακριβώς ΔΕΝ είναι αλιευτική διαχείριση.