New research shows that a fifth of the world’s biggest fisheries depend upon healthy seagrass meadows. The meadows are also crucial for small-scale fisheries.

Seagrasses are marine flowering plants that form extensive meadows in shallow seas on all continents except Antarctica. A study by scientists at Cardiff University and Stockholm University shows that seagrasses should be recognised and managed to maintain and maximise their role in global fisheries production.

In the Mediterranean, seagrass covers less than 2% of the sea floor, but seagrass-associated fish and invertebrate species comprise 30%–40% of the total value of commercial fisheries landings

One of the author’s of the study, Dr Leanne Cullen-Unsworth commented: “Seagrass meadows support global fisheries productivity by providing nursery habitat for commercial fish stocks such as tiger prawns, conch, Atlantic cod and white spotted spinefoot”.

As well as providing a nursery for commercial fish species, seagrass provides shallow water habitat for harvesting invertebrates. Seagrass invertebrate fisheries provide a source of essential protein for some of the most vulnerable people in tropical coastal communities. Invertebrate gleaning activity is expanding globally and although it’s a significant global activity, often conducted by women and children, it is not usually included in fishery statistics and rarely considered in resource management strategies.

Seagrass harvesting

Seagrasses also support fisheries in adjacent and deep water habitats, by creating expansive fishery habitat rich in fauna, and by providing nourishment to adjacent fisheries.

The potential value of seagrass meadows in supporting food security remains largely underappreciated, says Dr Cullen-Unsworth. In particular there is disparity between the significant economic benefits supplied by the seagrass nurseries and the poor levels of funding and management afforded to prevent seagrass degradation. She continued
“The coastal distribution of seagrass means it is vulnerable to a multitude of both land and sea based threats, such as land runoff, coastal development, boat damage and trawling. There is a global rapid decline of seagrass and when seagrass is lost there is strong evidence globally that fisheries and their stocks often become compromised with profound negative economic consequences. To make a change, awareness of seagrasses role in global fisheries production must pervade the policy sphere. We urge that seagrass requires targeted management to maintain and maximise their role in global fisheries production.”

Dogfish in Seagrass

Seagrass meadows are currently experiencing rapid decline with loss estimated at around 7% of their global distribution annually

There is now an app for Mapping Seagrass

Divers around the world can become citizen scientists who contribute to marine conservation with just a few taps of their phone. Get along to Seagrass Spotter and make your contribution.

Further Reading

Seagrass meadows support global fisheries production, Richard K.F. Unsworth Lina Mtwana Nordlund Leanne C. Cullen-Unsworth. Conservation Letters, 21 May 2018

Photos: © 2018 The Authors. Conservation Letters published by Wiley Periodicals, Inc. (CC BY 4.0)

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