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Published: 11 February 2013

Sea turtles caught up in ghostnets’ random harvest

Britta Denise Hardesty and Chris Wilcox

Each year around 640,000 tonnes of fishing gear is lost or thrown overboard by the fisheries around the world. These ‘ghostnets’ drift through the oceans and can continue fishing for many years. They kill huge numbers of marine mammals, sea turtles and sea birds, and cause significant loss of biodiversity.

Entangled sea turtles being freed from dangerous ghost nets by an Australian Fisheries Management Authority officer.
Credit: AFMA

One study showed fur seal populations declined around 5 per cent each year. Ghostfishing of commercially valuable fish species also reduces food resources.

Ghostnets are a global problem: they’re found even on remote atolls thousands of kilometres from commercial ports. But they are a particular problem in Australia’s Gulf of Carpentaria. Here, ghostnets wash ashore at densities reaching up to three tonnes/km, among the highest in the world.

We don’t know where more than half the nets come from, but of the nets we can identify, most come from fisheries in neighbouring Asian countries. About 4 per cent come from Australia. Because of the large amount of illegal fishing that has occurred in the region, it’s not clear whether they were lost or left behind intentionally.

Ghostfishing in the Gulf is known to kill sharks, crocodiles, and dugongs, as well as other fish and invertebrates. But it is turtles that are most at threat.

Australia is home to six of the world’s seven threatened species of marine turtle. During a recent cleanup of ghostnets on beaches in the Gulf, 80per cent of animals recorded in nets were marine turtles, including Olive Ridley, Hawksbill, Green and Flatback turtles. Getting tangled in ghostnets is one of the most common causes of death for marine turtles in Australia.

It’s expensive to get out on planes and ships, so most of the data we have about marine debris comes not from the sea itself. Instead we use beach clean ups of rubbish washed ashore to estimate what might be drifting out there in the ocean.

In our research, we worked with GhostNets Australia and used data collected by Indigenous rangers on the number of ghostnets found during beach cleanups in the Gulf of Carpentaria. We combined that with a model of ocean currents. This let us simulate the likely paths that ghostnets take to get to their landing spots on beaches in the Gulf.

If you’re a marine turtle, your most likely cause of death is getting tangled in a discarded fishing net.

Beyond finding out where ghostnets occur in the Gulf, we wanted to actually estimate their impact on threatened marine turtles. So we combined our model with data about where turtles exist in the Gulf, using turtle by-catch records from the prawn trawl fishery that operates in the region. We crosschecked our predictions about where turtles would wash ashore tangled in ghostnets with real life data on turtles caught in ghostnets found by the rangers.

This showed us where the hotspots are. Ghostfishing for turtles is concentrated in an area along the eastern margin of the Gulf and in a wide section in the southwest extending up the west coast.

Most ghostnets enter the Gulf from the northwest and move clockwise along its shores. This means we can help protect biodiversity in the region by intercepting nets as they enter the Gulf, before they reach the high-density turtle areas along the south and east coastlines.

Nets arriving here could be monitored by aerial or satellite surveys or coastal surveillance programs. Run from a nearby port, this surveillance could focus on a relatively small area north of the Gulf. Intercepting nets along the northeast of the Gulf should reduce much of their impact: they will no longer sweep through the Gulf and meet turtles along the south and east margins.

Encouraging fishers to recover lost or damaged nets could also reduce the prevalence of ghostnets in our seas. One idea is to offer incentives for fishing boats to return fishing gear. Another is to set up waste disposal sites at ports.

Our work points the way forward for understanding the global threat from marine debris and making predictions that can guide regulation, enforcement, and conservation action.

This approach can easily be expanded to the level of whole oceans for a huge range of different animals, from sea birds to seals. Models that predict global densities of marine debris already exist, thanks to other researchers.

Combining models such as these with species distribution data, even at coarse scales, would show us the global hotspots where marine debris meets commercially valuable or threatened marine species.

This could pinpoint where prevention and clean-ups could really make a difference to biodiversity and help us mitigate the impact of marine debris on the world’s marine wildlife.

Britta Denise Hardesty is a Research Scientist with CSIRO Sustainable Ecosystems and Chris Wilcox a Senior Research Scientist with CSIRO Marine & Atmospheric Research. This article is republished with permission from The Conversation.

Published: 17 December 2012

Make your next holiday a sustainable one

Rosemary Black

It’s holiday time and many of us are heading off overseas, or thinking about where to spend our next vacation. Our choice of destination, accommodation and activities can make a difference to local economies, cultures and environments. Dr Rosemary Black offers some advice on how we can make our holidays more sustainable.

A local villager foraging for shellfish on Atauro Island. The island, 35 km south of Dili and separated from the Timor-Leste mainland, has a population of 8000 living among five villages. Eco-tourism is a major source of income, supplementing subsistence fishing and farming. Adventure Ecotourism students from Charles Sturt University <a href="">visited the Tua Koin ecotourism village</a> to study first hand how local people are <a href="">managing the enterprise sustainably</a>.
A local villager foraging for shellfish on Atauro Island. The island, 35 km south of Dili and separated from the Timor-Leste mainland, has a population of 8000 living among five villages. Eco-tourism is a major source of income, supplementing subsistence fishing and farming. Adventure Ecotourism students from Charles Sturt University visited the Tua Koin ecotourism village to study first hand how local people are managing the enterprise sustainably.
Credit: spiderman_frank/panoramio under Creative Commons CC BY-NC-SA 3.0 licence

For developing countries like Fiji, Thailand and Indonesia, tourism is a major source of foreign income and a potentially significant driver for economic growth. So, while we often hear about cases where tourism may have detrimental impacts on the local environment and communities, it can also provide positive benefits.

Sustainable tourism is tourism that is environmentally, economically and socially sustainable – that means its aim is to minimise impact on the environment and communities, and at the same time contribute positively to local communities.

What can you do to ensure that your tourism experiences are sustainable?

The first thing is to realise you are a vital part of the global tourism industry, and you can help transform the way the world travels by being a responsible traveller.

As a tourist or potential tourist, ask yourself ‘am I contributing to the local community or environment?’ Travel can and should be much more than simply visiting places, taking pictures and buying souvenirs; it can inspire cultural awareness, tolerance, and commitment to environmental responsibility.

Try to minimise your impact on communities and the environment. One of the most important things you can do as a responsible traveller is to make informed choices before and during your trip. With a little planning, you can improve the quality of your trip, while making a real difference to the people and places you visit.

When choosing destinations, accommodation and tour operators, consider which ones work to protect the environment and benefit local cultures and communities.

Do your homework, ask questions, seek out quality products by looking for accredited operators, guides and accommodation, and look for opportunities to give something back to the local community or environment – many tourism operators are supporting community projects and offering travellers the opportunity to get involved.

By exploring alternative travel choices, you can have a unique trip and avoid leaving negative marks on cultures, economies, and the environment, while making a positive impact on the people and places you visit.

Fijian villagers prepare to perform a ceremonial dance for tourists: seeking out genuine cultural experiences is rewarding for both travellers and the local communities.
Fijian villagers prepare to perform a ceremonial dance for tourists: seeking out genuine cultural experiences is rewarding for both travellers and the local communities.
Credit: peachygreen/flickr under Creative Commons CC BY-NC-ND 2.0 licence

Here are some useful dos and don’ts for your next trip away from The International Ecotourism Society. These are useful for holidays in Australia and overseas.

1. The hotel: Ask about environmental policies and practices. Talk with staff about working conditions. Does the hotel support community projects?

2. Language: Learn a few words of the local language and use them.

3. Dress: Read up on local conventions and dress appropriately. In many countries, modest dress is important.

4. Behaviour: Be respectful of local citizens’ privacy. Ask permission before entering sacred places, homes, or private land.

5. Photos: Be sensitive to when and where you take photos/video of people. Always ask first.

6. Environment: Respect the natural environment. Never touch or harass animals. Always follow designated trails. Support conservation by paying entrance fees to parks and protected sites.

7. Animal products: Never buy crafts or products made from protected or endangered animals.

8. Pay the fair price: Don’t engage in overly aggressive bargaining for souvenirs. Don’t short-change on tips for services.

9. Buy local: Choose locally owned lodges, hotels, and B&Bs. Use local buses, car rental agencies, and airlines. Eat in local restaurants, shop in local markets, and attend local festivals/events.

10. Hire local guides: Enrich your experience and support the local economy. Ask guides if they are licensed and live locally. Are they recommended by tour operators?

A book I recently co-edited explores the issues of how sustainable tourism can provide positive benefits to local people and the environment in developing countries. Sustainable Tourism and the United Nations’ Millennium Development Goals: Effecting Positive Change brings together research and examples from around the world of sustainable tourism initiatives.

The UN Millennium Development Goals focus on trying to address global issues like poverty alleviation, primary health care and education for all, environmental sustainability and gender equity. We used this as a framework for the book and explored how sustainable tourism can help support and meet the goals.

We didn’t only have academics writing chapters but sought out local people who actually run sustainable tourism operations in places like Nepal, Costa Rica, Fiji and Indonesia.

I think this book has an important message for tourists from developed countries such as Australia who travel overseas to enjoy the different culture and environment of a developing country – that they can play an important role as responsible tourists and that tourism can help support the health and well-being of local people, assist biodiversity conservation efforts, and preserve local cultural heritage, while also supporting education, equal opportunities for women and basic human rights.

Dr Rosemary Black is a senior lecturer and social researcher in the School of Environmental Sciences at Charles Sturt University specialising in sustainable tourism, heritage interpretation, outdoor recreation and tour guiding. Rosemary previously worked as a park ranger in NSW and adventure travel guide in Nepal, India, China, Tibet and Australia. This is a lightly edited version of an article first published in Open Forum, an independent, non-profit think-tank built around a community blog moderated by Global Access Partners (GAP).

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