Seagrass planting strategy needed to remove fast food option

January 18, 2016 by Natasha Prokop, Sciencenetwork Wa, Science Network WA
Seagrass planting strategy needed to remove fast food option
Grazed Posidonia plant. Credit: John Statton

Efforts to restore Shark Bay's seagrass meadows by transplanting Posidonia australis at the edge of existing meadows are being hampered because resident fish are using the new seagrass as fast food.

Local researchers found extensive grazing in the zone between the edge of the existing meadow and 10m out from its edge, but negligible grazing pressure further from the meadow edge.

This phenomenon, known as an 'edge effect,' arises because herbivores, like fish, use the existing meadow as a refuge and then venture out and dine on the nearest snack, which in this case happens to be the fledgling seagrass plants.

Shark Bay has one of the largest continuous in the world, according to UWA Oceans Institute researcher Dr John Statton.

These areas provide food for animals like dugongs and sea turtles, habitat for fishes and which buffer beach-eroding wave energy.

But as with many areas in WA Shark Bay has lost seagrass cover due to historical coastal development and, more recently, marine heatwaves.

Because of the slow growth of the impacted seagrass species, natural recovery has been limited.

"You're looking at decades to centuries for some of these species [to recover]," Dr Statton says.

"Which is why we're really pushing for restoration, to help push that process along and to get the seagrasses to recover in a more reasonable timeframe," he says.

Seagrass planting strategy needed to remove fast food option
Posidonia australis fruit. Credit: John Statton

The current study, which determined that plants located near the meadow edge were less likely to survive, may assist in planning future restoration activities.

"If we know that planting a transplant nearby to the is going to result in a lot of grazing…we can put in some intervention measures, to prevent those plants from being eaten," Dr Statton says.

These management strategies could include planting in the less vulnerable 30-50m zone, herbivore exclusion with cages, or planting in dense patches.

Dr Statton and his colleagues are in the process of systematically assessing the ecological processes that might limit establishing seagrasses in degraded areas.

They are primarily investigating a novel approach using seeds, rather than adult cuttings.

He says this technique is showing promise and could prove to be a cost-effective method for large-scale seagrass restoration in WA.

Explore further: Tropical seagrass examined for light pressures

Related Stories

Tropical seagrass examined for light pressures

April 2, 2015

Research into seagrass susceptibility to dredging activities has revealed exactly how fragile some of the tropical marine plants species are when faced with a decreased level of light.

Seagrass restoration paying off for eastern shore

October 30, 2015

Seagrasses are crucial to the health of shallow coastal marine environments, in Virginia and worldwide. Seagrass meadows provide habitat and serve as nursery and feeding grounds to a diverse range of sea creatures – crustaceans, ...

Save the seagrass

August 12, 2014

Seagrass meadows provide the ideal place for young fish to thrive, say NERC-funded scientists researching the importance of these habitats for commercial fishing.

Recommended for you

Cosmic dust forms in supernovae blasts

February 20, 2019

Scientists claim to have solved a longstanding mystery as to how cosmic dust, the building blocks of stars and planets, forms across the Universe.

Earth's atmosphere stretches out to the moon – and beyond

February 20, 2019

The gaseous layer that wraps around Earth reaches up to 630,000 kilometers away, or 50 times the diameter of our planet, according to a new study based on observations by the ESA/NASA Solar and Heliospheric Observatory, SOHO, ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.