4 February 2011

Stunning Lord Howe Island, 700 kilometres north-east of Sydney, was listed as a UNESCO World Heritage Area in 1982. It is widely regarded as a pristine environment, with over 70% of the island protected from development and visitor numbers strictly limited to 400 at any one time.

Skeleton of a Flesh-footed Shearwater chick containing chunks of plastic. Large fragments like these almost certainly cause mortality but tiny particles also release toxins. Photo by Ian Hutton.

Sadly, even remote islands like Lord Howe are not immune to the impacts of human activities. Despite North Bay and iconic Ned’s Beach being repeatedly recognised as some of Australia’s cleanest beaches, these and many of the Lord Howe beaches are now littered with plastic bottles, lids, and derelict fishing gear.

Despite the implementation of strict international legislation aimed at reducing the amount of marine debris originating from ocean and land-based sources (e.g. MARPOL Annex V), debris, particularly plastic, continues to accumulate worldwide with an estimated 20-30 million items entering the ocean each day.

More than 200 seabird species have been reported to ingest plastic debris, presumably mistaking it for food. Adult birds then return to the breeding colony and ‘off-load’ the plastic they ingested to their chicks during feeding. Plastic debris is known to accumulate hydrophobic organic toxins such as polychlorinated biphenyls (PCBs) at up to 106x ambient seawater concentrations.  Once ingested, debris can block or rupture the digestive tract and leak contaminants into the bird’s blood stream resulting in stomach ulcerations, liver damage, infertility, and in many cases, death.

In North America, the now infamous ‘North Pacific Garbage Patch’ has received significant media attention.  The tragic beauty of thousands of dead Laysan Albatross chicks with stomachs full of colourful bottle caps captured by photographer Chris Jordan has contributed significantly to public awareness of this serious issue.

Plastic sand! Middle Beach on Lord Howe Island may be one of Australia's "cleanest". But as this photo shows, particles of plastic debris wash up on every high tide.

In stark contrast, awareness of marine debris impacts in Australia is exceptionally low.  But the truth is, marine debris is here.  In our backyards, threatening our species and oceans and slowly converting our iconic sandy beaches into colourful, yet toxic plastic reservoirs (see image).

In 2009, the Australian government identified the ingestion of plastic debris by marine vertebrates as one of only a handful of ‘Key Threatening Processes’.  The Flesh-footed Shearwater (Puffinus carneipes) is one of many at-risk species, with 90% of chicks on Lord Howe Island having ingested considerable quantities of plastic.

Lord Howe Island is home to the world’s single largest population of Flesh-footed Shearwaters, which declined by more than 50% during 1978-2009. Repeated years of low breeding success are implicated in the decline, likely the result of chick mortality due to the ingestion of plastic.  Plastic-based chemicals almost certainly contribute to this decline, with a recent study showing mercury levels in Flesh-footed Shearwaters to be multiple orders of magnitude above what is known to be toxic to birds.

In collaboration with the Lord Howe Island Board, a field research project has been proposed for February-April 2011 with the aim of quantifying the effect of marine debris on the Lord Howe Island ecosystem, including Flesh-footed Shearwaters, and identifying possible ways to mitigate the impacts.  Project sponsorship is sought from corporations, non-profits, and/or individuals who are passionate about seabird conservation.  Donations can be as little as covering the cost of a flight or the Research Station accomodation fees on Lord Howe.  Interested parties are asked to visit http://www.jenniferlavers.org/donate/

Dr Jennifer Lavers, is a Wildlife Ecologist with CSIRO in Hobart.