Climate change is causing tuna to migrate, which could spell catastrophe for the small islands that depend on them


Katherine Seto, University of Wollongong; Johann Bell, University of Wollongong; Quentin Hanich, University of Wollongong, and Simon Nicol, University of CanberraSmall Pacific Island states depend on their commercial fisheries for food supplies and economic health. But our new research shows climate change will dramatically alter tuna stocks in the tropical Pacific, with potentially severe consequences for the people who depend on them.

As climate change warms the waters of the Pacific, some tuna will be forced to migrate to the open ocean of the high seas, away from the jurisdiction of any country. The changes will affect three key tuna species: skipjack, yellowfin, and bigeye.

Pacific Island nations such as the Cook Islands and territories such as Tokelau charge foreign fishing operators to access their waters, and heavily depend on this revenue. Our research estimates the movement of tuna stocks will cause a fall in annual government revenue to some of these small island states of up to 17%.

This loss will hurt these developing economies, which need fisheries revenue to maintain essential services such as hospitals, roads and schools. The experience of Pacific Island states also bodes poorly for global climate justice more broadly.

Island states at risk

Catches from the Western and Central Pacific represent over half of all tuna produced globally. Much of this catch is taken from the waters of ten small developing island states, which are disproportionately dependent on tuna stocks for food security and economic development.

These states comprise:

  • Cook Islands
  • Federated States of Micronesia
  • Kiribati
  • Marshall Islands
  • Nauru
  • Palau
  • Papua New Guinea
  • Solomon Islands
  • Tokelau
  • Tuvalu

Their governments charge tuna fishing access fees to distant nations of between US$7.1 million (A$9.7 million) and $134 million (A$182 million), providing an average of 37% of total government revenue (ranging from 4-84%).



Tuna stocks are critical for these states’ current and future economic development, and have been sustainably managed by a cooperative agreement for decades. However, our analysis reveals this revenue, and other important benefits fisheries provide, are at risk.




Read more:
Warming oceans are changing Australia’s fishing industry


Climate change and migration

Tuna species are highly migratory – they move over large distances according to ocean conditions. The skipjack, yellowfin and bigeye tuna species are found largely within Pacific Island waters.

Concentrations of these stocks normally shift from year to year between areas further to the west in El Niño years, and those further east in La Niña years. However, under climate change, these stocks are projected to shift eastward – out of sovereign waters and into the high seas.

Under climate change, the tropical waters of the Pacific Ocean will warm further. This warming will result in a large eastward shift in the location of the edge of the Western Pacific Warm Pool (a mass of water in the western Pacific Ocean with consistently high water temperatures) and subsequently the prime fishing grounds for some tropical tuna.

This shift into areas beyond national jurisdiction would result in weaker regulation and monitoring, with parallel implications for the long-term sustainability of stocks.

Pacific Tuna: Feeling the Heat.

What our research found

Combining climate science, ecological models and economic data from the region, our research published today in Nature Sustainability shows that under strong projections of climate change, small island economies are poised to lose up to US$140 million annually by 2050, and up to 17% of annual government revenue in the case of some states.

The Intergovernmental Panel on Climate Change (IPCC) provides scenarios of various greenhouse gas concentrations, called “representative concentration pathways” (RCP). We used a higher RCP of 8.5 and a more moderate RCP of 4.5 to understand tuna movement in different emissions scenarios.




Read more:
Citizen scientist scuba divers shed light on the impact of warming oceans on marine life


In the RCP 8.5 scenario, by 2050, our model predicted the total biomass of the three species of tuna in the combined jurisdictions of the ten Pacific Island states would decrease by an average of 13%, and up to 20%.

But if emissions were kept to the lower RCP 4.5 scenario, the effects are expected to be far less pronounced, with an average decrease in biomass of just 1%.

While both climate scenarios result in average losses of both tuna catches and revenue, lower emissions scenarios lead to drastically smaller losses, highlighting the importance of climate action.

These projected losses compound the existing climate vulnerability of many Pacific Island people, who will endure some of the earliest and harshest climate realities, while being responsible for only a tiny fraction of global emissions.

Large tuna fish on the back of a fishing boat
Fishing access fees make up a large proportion of government revenue for these Pacific Island nations.
Shutterstock

What can be done?

Capping greenhouse gas emissions, and reducing them to levels aligning with the Paris Agreement, would reduce multiple climate impacts for these states, including shifting tuna stocks.

In many parts of the world, the consequences of climate change compound upon one another to create complex injustices. Our study identifies new direct and indirect implications of climate change for some of the world’s most vulnerable populations.




Read more:
The 2016 Great Barrier Reef heatwave caused widespread changes to fish populations


The Conversation


Katherine Seto, Research Fellow, University of Wollongong; Johann Bell, Visiting Professorial Fellow, University of Wollongong; Quentin Hanich, Associate Professor, University of Wollongong, and Simon Nicol, Adjunct professor, University of Canberra

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Tens of thousands of tuna-attracting devices are drifting around the Pacific



Fish are attracted to floating objects, especially with dangling ropes or nets.
WorldFish/Flickr, CC BY-NC-SA

Joe Scutt Phillips, Secretariat of the Pacific Community; Alex Sen Gupta, UNSW; Graham Pilling, Secretariat of the Pacific Community, and Lauriane Escalle, Secretariat of the Pacific Community

Tropical tuna are one of the few wild animals we still hunt in large numbers, but finding them in the vast Pacific ocean can be tremendously difficult. However, fishers have long known that tuna are attracted to, and will aggregate around, floating objects such as logs.

In the past, people used bamboo rafts to attract tuna, fishing them while they were gathered underneath. Today, the modern equivalent – called fish aggregating devices, or FADs – usually contain high-tech equipment that tell fishers where they are and how many fish have accumulated nearby.




Read more:
Sustainable shopping: how to buy tuna without biting a chunk out of the oceans


It’s estimated that between 30,000 and 65,000 man-made FADs are deployed annually and drift through the Western and Central Pacific Ocean to be fished on by industrial fishers. Pacific island countries are reporting a growing number of FADs washing up on their beaches, damaging coral reefs and potentially altering the distribution of tuna.

Our research in two papers, one of which was published today in Scientific Reports, looks for the first time at where ocean currents take these FADs and where they wash up on coastlines in the Pacific.

A yellowfin tuna caught by purse seine fishers. This individual is one of the largest that can be caught using FADs.
Lauriane Escalle

Attracting fish and funds

We do not fully understand why some fish and other marine creatures aggregate around floating objects, but they are a source of attraction for many species. FADs are commonly made of a raft with 30-80m of old ropes or nets hanging below. Modern FADs are attached to high-tech buoys with solar-powered electronics.

The buoys record a FAD’s position as it drifts slowly across the Pacific, scanning the water below to measure tuna numbers with echo-sounders and transmitting this valuable information to fishing vessels by satellite.

Tuna hauled aboard the fishing vessel Dolores. The tuna trade in the Pacific Ocean is worth more than US$6 billion a year.
Siosifa Fukofuka (SPC), Author provided

Throughout their lifetimes FADs may be exchanged between vessels, recovered and redeployed, or fished and simply left to drift with their buoy to further aggregate tuna. Fishers may then abandon them and remotely deactivate the buoys’ satellite transmission when the FAD leaves the fishing area.

The Western and Pacific Ocean provides around 55% of the worlds’ 5 million tonne catch of tropical tuna, and is the main source of skipjack, yellowfin and bigeye tuna worth some US$6 billion annually.

Pacific Islanders with a FAD buoy that washed up on their reef.
Joe Scutt Phillips, Author provided

Fishing licence fees can provide up to 98% of government revenue for some Pacific Island countries and territories. These countries balance the need to sustainably manage and harvest one of the only renewable resources they have, while often having a limited capacity to fish at an industrial scale themselves.

FADs help stabilise catch rates and make fishing fleets more profitable, which in turn generate revenue for these nations.

However, they are not without problems. Catches around FADs tend to include more bycatch species, such as sharks and turtles, as well as smaller immature tuna.

The abandonment or loss of FADs adds to the growing mass of marine debris floating in the ocean, and they increasingly damage coral as they are dragged and get caught on reefs.

Perhaps most importantly, we don’t know how the distribution of FADs affects fishing effort in the region. Given that each fleet and fishing company has their own strategy for using FADs, understanding how the total number of FADs drifting in one area increases the catch of tuna is crucial for sustainably managing these valuable species.

Where do FADs end up?

Our research, published in Environmental Research Communications and Scientific Reports, used a regional FAD tracking program and fishing data submitted by Pacific countries, in combination with numerical ocean models and simulations of virtual FADs, to work out how FADs travel on ocean currents during and after their use.

In general, FADs are first deployed by fishers in the eastern and central Pacific. They then drift west with the prevailing currents into the core industrial tropical tuna fishing zones along the equator.

We found equatorial countries such as Kiribati have a high number of FADs moving through their waters, with a significant amount washing up on their shores. Our research showed these high numbers are primarily due to the locations in which FADs are deployed by fishing companies.

In contrast, Tuvalu, which is situated on the edge of the equatorial current divergence zone, also sees a high density of FADs and beaching. But this appears to be an area that generally aggregates FADs regardless of where they are deployed.

Unsurprisingly, many FADs end up beaching in countries at the western edge of the core fishing grounds, having drifted from different areas of the Pacific as far away as Ecuador. This concentration in the west means reefs along the edge of the Solomon Islands and Papua New Guinea are particularly vulnerable, with currents apparently forcing FADs towards these coasts more than other countries in the region.

FAD found beached in Touho (New Caledonia) in 2019.
A. Durbano, Association Hô-üt’, Author provided

Overall, our studies estimate that between 1,500 and 2,200 FADs drifting through the Western and Central Pacific Ocean wash up on beaches each year. This is likely to be an underestimate, as the tracking devices on many FADs are remotely deactivated as they leave fishing zones.

Using computer simulations, we also found that a significant number of FADs are deployed in the eastern Pacific Ocean, left to drift so they have time to aggregate tuna, and subsequently fished on in the Western and Central Pacific Ocean. This complicates matters as the eastern Pacific is managed by an entirely different fishery Commission with its own set of fisheries management strategies and programmes.

Growing human populations and climate change are increasing pressure on small island nations. FAD fishing is very important to their economic and food security, allowing access to the wealth of the ocean’s abundance.




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We need to safeguard these resources, with effective management around the number and location of FAD deployments, more research on their impact on tuna and bycatch populations, the use of biodegradable FADs, or effective recovery programs to remove old FADs from the ocean at the end of their slow journeys across the Pacific.The Conversation

Joe Scutt Phillips, Senior Fisheries Scientists (Tuna Behavioural Ecology), Secretariat of the Pacific Community; Alex Sen Gupta, Senior Lecturer, School of Biological, Earth and Environmental Sciences, UNSW; Graham Pilling, Principal Fisheries Scientist, Secretariat of the Pacific Community, and Lauriane Escalle, Fisheries Scientist, Secretariat of the Pacific Community

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Sustainable shopping: how to buy tuna without biting a chunk out of the oceans



File 20171205 23047 f6viwh.jpg?ixlib=rb 1.1
Canned tuna is an Australian pantry staple.
NOAA

Candice Visser, University of Wollongong and Quentin Hanich, University of Wollongong

Shopping can be confusing at the best of times, and trying to find environmentally friendly options makes it even more difficult. Welcome to our Sustainable Shopping series, in which we ask experts to provide easy eco-friendly guides to purchases big and small.


Tuna is the most popular canned fish eaten in Australia and one of the most popular fish produced worldwide. The total catch of tuna in 2013 was about 7.4 million tonnes.

Tuna is a massive industry and most of this catch ends up in cans. But while each can of tuna might look similar, the environmental impacts of different brands vary. So, with a sea of “eco-friendly” labels and choices, how do you know which is the most sustainable?


Read more: Australian endangered species – Southern Bluefin Tuna


Almost all Australian canned tuna is imported

Australia produces large amounts of high-end seafood such as rock lobster, abalone and fresh tuna, but most of this doesn’t end up in our supermarkets – it is exported to countries willing to pay more. Instead, roughly 70% of all seafood eaten in Australia is imported. Most of this includes lower-value products such as frozen fish, frozen prawns and canned tuna.

Cans of tuna line the supermarket shelves. Which one is the choice for the sustainable shopper?
www.shutterstock.com

Australia is a major market for canned tuna. Almost all of the canned tuna sold here comes from Thailand, which processes about half of the world’s tuna supply. It is now almost impossible to buy Australian-produced canned tuna since large-scale production in Australia ended in May 2010.

While it is not unusual for a developed country to import large amounts of seafood, Australia is failing to meet international standards for sustainable seafood trade. Australia has strict requirements for seafood exports, but seafood imports are largely unregulated. This means it can be difficult to know if the imported seafood you buy was caught sustainably or even legally.

Catching 7.4 million tonnes of tuna

High global demand drives unsustainable fishing practices. These practices include overfishing, issues related to bycatch (which is the accidental catch of other marine animals like dolphins, turtles and seabirds), and “illegal, unregulated and unreported” (IUU) fishing. Now, 77% of the world’s fisheries are fished at their limit or beyond.

Of the many different types of tuna species, skipjack tuna is the most sustainable option.
FAO

Unsustainable fishing practices have devastating effects on the health of the marine ecosystem and the livelihoods of fishers. With this in mind, it is more important than ever to know about the origin of your fish.

Some species of tuna are fished at sustainable rates, whereas others are overfished. The most common species that end up in cans are skipjack and yellowfin tuna. Both of these species have sustainable stocks in the Western and Central Pacific Ocean (WCPO). Skipjack also has sustainable stocks in the Indian Ocean. Higher-value species such as bigeye and bluefin varieties are usually reserved for sushi and sashimi markets. Southern bluefin tuna is overfished and is listed as critically endangered by the IUCN.


Read more: Australian endangered species: southern bluefin tuna


The type of catch matters

The most sustainable fishing methods for tuna are “pole-and-line” and “FAD-free purse seine”. However, each method has a catch.

Pole-and-line fishing is used to catch tuna species one fish at a time.
Paul Hilton/Wikimedia Commons, CC BY-SA

Pole-and-line fishing is the traditional method of using a pole, line and hook to catch fish. The rate of bycatch is small because fishers can catch and release non-tuna species. However, bait fish are used to attract the tuna, which can have a large impact if the bait fish is not caught in a sustainable way. Due to the labour-intensive nature of pole-and-line fishing and dependence on bait fish, this method makes up only a small proportion of the total tuna caught and is unable to supply tuna in large amounts.

Purse seine catches tuna by surrounding them with a net and hauling the catch up to the ship. When a FAD device is used, bycatch can also be caught.
FAO

Purse seine fisheries use a large net to surround a school of fish. In recent years purse seiners have increasingly used fish aggregating devices (FAD) to attract tuna and increase their efficiency. However, FADs also attract bycatch and juvenile tuna and are poorly regulated. Therefore, only purse seine fisheries that set on free-swimming schools of tuna are considered sustainable.

Quick guide to better tuna

Quick guide: The right can of tuna.
Author provided

What can you do?

1. Read the label

Examine the details on the back of the can for tuna species, fishing method and catch location. There are sustainable options for each of these categories.

The best approach is to opt for skipjack before yellowfin or other tuna varieties. Next, choose tuna caught using “pole-and-line” or “FAD-free purse seine” before “longline” or “purse seine”. Then, check for tuna caught in the Western Central Pacific Ocean – this may appear on the can as FAO Nr. 71. If the can doesn’t at least identify the species or fishing method, it’s probably not worth your time.

2. Consider eco-labels over unverified self-claims

Eco-labels and eco-claims often feature prominently on tuna cans. Eco-labels are market-based tools used to promote sustainable practices. Decoding them can seem challenging, but it doesn’t have to be.

Dolphin-safe labels only focus on the impacts of fishing on dolphins.
NOAA

First, it is important to recognise that a dolphin-safe label is not a sustainability label. It focuses only on the impacts of fishing on dolphins. Dolphin-safe doesn’t consider tuna catch levels or other socio-environmental impacts. Most importantly, it doesn’t require independent third-party verification.

In contrast, some newer eco-labels consider a wider set of impacts including target species stock levels, impact on other species and even the social impact on fishers – such as fair pay and work conditions.

So far, MSC is the only label to be recognised by the Global Sustainable Seafood Initiative (GSSI), but keep in mind this label is not without criticism.

Look for MSC certification that is sustainable and eco-friendly.
deckhand/flickr, CC BY-NC-ND

In recent months, the MSC-certified Pasifical brand has been criticised because its FAD-free purse seine sourced tuna are transported on vessels that can also catch FAD-caught purse seine tuna. Some commentators argue that this enables unsustainable FAD-caught fisheries to continue operating.

On the other hand, MSC has the strongest chain of custody. It can trace every can of tuna from the supermarket shelf all the way back to the fishery. It’s not clear whether the original criticism was driven by competition for supermarket shelf space, as some industry insiders have claimed.


Read more: Here’s why your sustainable tuna is also unsustainable


3. Download seafood guides

Various online guides are also available to help consumers choose sustainable seafood options. These guides rank and recommend seafood using a stoplight system. The recommendations are based on available scientific research or a defined set of criteria.

In Australia, Greenpeace publishes a Canned Tuna Guide that ranks available brands. Australia’s Sustainable Seafood Guide provides recommendations for seafood generally.

Guides are also produced by Monterey Bay Aquarium Seafood Watch for the US, Ocean Wise for Canada and WWF’s Fish Forward Project for South Africa and several countries in the EU and Asia.

4. Future technologies, supply chains and transparency

While the steps above assist with making sustainable seafood choices, it doesn’t help if the fish you’re buying has been mislabelled. There is still uncertainty related to transparency and traceability in the supply chain.

To help combat this problem, Coles has partnered with WWF to ensure the seafood it sells is sustainably sourced. Aldi has also introduced an initiative called “Trace Your Tuna” to link tuna to its catch location.

New applications that use tracking data are also developing. Apps are available that scan QR codes and barcodes to provide consumers with extra information about the origins of lots of different products including seafood. These include Oziris in Australia, ThisFish in Canada and the Seafood Traceability System offered by the Korean government.

Simultaneously, new initiatives such as Global Fishing Watch are providing open access to vessel movement data, providing tremendous opportunities for transparency and traceability.

The ConversationIn short, the easiest way to make a sustainable choice when buying canned tuna is to check the contents label and look for a credible eco-label. If you have a little more time, it might be worthwhile to check out seafood recommendation guides or to download a product tracking app on your smartphone.

Candice Visser, PhD Candidate, University of Wollongong and Quentin Hanich, Associate Professor, University of Wollongong

This article was originally published on The Conversation. Read the original article.

Shark Numbers Growing off Eastern Australia


Shark numbers appear to be growing off the east coast of Australia. In recent days large numbers of sharks, including Tiger Sharks have been spotted of the southeastern coast of Queensland at Teewah, feasting on large schools of baitfish and tuna.

For more information on sharks visit:

http://www.removesharknets.com/

http://www.sharksinternational.org/