Report calculates value of fish breeding grounds

A NEW study has, for the first time, put a dollar value on the contribution of Australia’s coastal ecosystems as breeding grounds for fish.

Researchers from Deakin University’s Centre for Integrative Ecology in the School of Life and Environmental Sciences calculated that a single hectare of seagrass supports 55,000 more fish a year compared with a seabed without vegetation.

Lead researcher, PhD candidate Holger Jänes from Deakin’s Blue Carbon Lab, said this represented a commercial value of fish of up to $21,200 per hectare per year.

“Understanding the value of coastal ecosystems is critically important because healthy beds of seagrass, mangrove swamps and tidal marshes sustain larger populations of fish than unhealthy or degraded areas,” Mr Jänes said.

“Mangroves support 19,000 fish per hectare a year and tidal marshes support 1700 fish per hectare a year.”

Mr Jänes said, while the most abundant fish across all three ecosystems were small, non-commercial species such as gobies and glassfish, the highest biomass production and economic value originated from larger, longer-lived fish that were regularly targeted by fisheries such as tharwine, bream and mullet.

“To better conserve, protect, restore and rehabilitate ecosystems degraded by human impact we must know their associated value to human wellbeing,” he said.

“Coastal ecosystems face a range of threats from climate change, coastal development, invasive species and nutrient run-off from farms and other sources.

“Over the past decades, we have lost more than 180sq km of seagrass in Victoria alone and this is a potential loss of fish production of millions of dollars.