Will Global Warming Turn The EPO Into The World’s Leading Tuna Catching Ground?

The United Nations Paris Agreement – for the first time – has brought nearly all nations into a common cause to undertake ambitious efforts to combat climate change and adapt to its effects, underlining the massive concerns that global warming is raising around the globe. 

With the United States being the only country to not stand in solidarity, the agreement shows there is major worldwide recognition of this substantial environmental threat, and the worrying impacts it will have on our planet.

As the world temperature rises, it is clearly going to have big impacts not only on the earth as a whole, but on many industries, including the tuna sector, which various nations rely on for a vital economic contribution. As climate change advances, along with it will come massive economic consequences.

Whether you think it is actually happening, or like Donald Trump, you believe it is a hoax, global warming is causing major concern on a global scale, and will shape many future environmental policies around the world. How it could shake up the tuna industry could be evident sooner than many would have expected.

In the Western and Central Pacific, according to a recent study, there will be major changes in terms of tuna stocks and catches; changes that the industry should be prepared for. Are we already seeing the implications, how fast will they strengthen, and what does it mean for the tuna business in the long term?

These are all questions that recent research from the Pacific Community (SPC) sought to answer. The studies of SPC scientists have found that increased ocean temperatures in the WCPO are causing uncomfortable conditions for several key tuna species and that tuna – most evidently skipjack and yellowfin – will move to find cooler areas.

These findings were explained to Atuna by Valerie Allain, Senior Fisheries Scientist at the SPC. She believes that in the next 35 years there will be a notable impact on tuna catches in the WCPO, caused by global warming. Ultimately this could mean serious implications for the major fleets that fish in the region, and also the resource owners, which depend heavily on the sale of fishing rights in their tuna-rich waters.

According to Allain, the major consequence of climate change for the tuna industry will be the displacement of skipjack and yellowfin tuna from the Western Pacific to the Eastern Pacific. Although the most obvious impacts are expected to hit around 2050, the changes will first come gradually.

This is because it has been forecasted by SPC models that there will be a notable decrease of the total biomass of skipjack and yellowfin tuna in the Western Pacific overall. “This is caused mainly by increased temperatures in the ocean…Temperature becomes higher than the range conformable for tuna species and tuna will move to find areas with cooler waters.”

The potential impacts of this are exaggerated by the fact that the WCPO is the largest tuna catching ground in the world, with over 60 percent of the skipjack volume landed globally netted in this region. According to the SPC study, this could change significantly, with a potentially major shift in stocks.

These are stocks that numerous Pacific island nations in the WCPO rely on massively, and in some cases – take PNA country Kiribati for example – revenue from their tuna resources and the fishing rights they sell in their EEZs contribute as much as 80 percent to national GDP.

In the PNA region as a whole, over 50 percent of the global skipjack landings are caught in the eight island nations’ waters, mostly by purse seiners. They buy Vessel Day Scheme (VDS) days for at least USD 8,000 apiece for access to the area. This has substantially boosted the “tuna revenue” earned by these small island developing states, with the VDS also aimed at bringing increased management over their resource to enhance the conservation of tuna stocks.

In 2016 it was stated that the total PNA revenue from its tuna fishery was well over USD 400 million, thanks to the implementation of the VDS. The scheme has been praised by the United Nations Environment Program, stating that it is a substantial contribution to the growth of sustainably caught tuna.

But another climate change impact that could notably lessen the tuna stock concentration in such island nations’ waters, and therefore have serious economic implications, is the “higher stratification of the water column,” stresses Allain. This means there is less mixing between surface water that is “nutrient-poor” and deeper water that is “nutrient-rich” in the WCPO. The nutrients therefore do not reach the surface where there is sunlight and where phytoplankton needs these minerals to grow.

With phytoplankton being at the base of the food chain, if there is less of it, then there is less zooplankton, less small fish and squids, and therefore fewer medium-sized and top predators like tuna, Allain explains.
She adds that the warming of surface water in the Western Pacific has therefore already had both direct and indirect effects on tuna. The direct impact is “uncomfortable” tuna moving to find cooler waters, and the indirect effect is the wider influence on the ecosystem, which in turn impacts tuna stocks.

According to Allain, climate change and these effects predicted by the SPC models, is a long term trend that is taking place in the background. Because of this the industry may not be recognizing the gradual impacts on a daily, monthly or even yearly basis.

When it comes to tuna stocks, this is especially due to the fact that climate change effects are also mixed with the impacts of fishing effort. Changes in the fleet size, capacity, effort, and types of fishing methods, can all have their own implications for tuna stocks, which can potentially mask the effects of climate change to some degree.

As well as this, shorter term environmental influences, like El Niño and La Niña, can cause distinct shifts in annual tuna catch data, which can also weaken the signs of the longer term changes caused by global warming.

When taking El Niño into account, one of the strongest on record in the WCPO was around 2015. This environmental phenomenon causes the warming of the ocean surface around the coast of South America, and tuna stocks in the EPO tend to move further westward and into the waters of the most eastern zones of the WCPO. During the 2015 El Niño period, skipjack catches were strongly abundant in the EEZ of Kiribati especially. Major fleets that had access to the country’s waters – most predominantly the Korean flagged purse seine fleet – saw dramatically increased catches.

“These shorter term events (eg. El Niño) can have a strong impact that is more obvious than the long term trend, which is more subtle and developing in the background,” Allain reiterates. This means that while fleets can see the obvious consequences of short term water warming or cooling, they may be less aware of the longer term impact that water temperatures can have on their business.
At a certain time these more gradual changes will become very clear in the WCPO, the SPC predicts, and much easier for boatowners to see. Allain talks of an “obvious decrease in [skipjack and yellowfin] biomass due to climate change from 2050-2080.”

That said, the potential increase in El Niño/La Niña frequency and/or strength due to climate change will possibly cause an even more immediate impact, she adds.

In the WCPO, the effect on tuna biomass will vary from zone to zone, the models show. “With the expected movement of fish towards the eastern side of the Pacific, decrease in biomass is expected in the equatorial western countries, while increase is expected in the eastern and more subtropical countries,” says Allain.

Equatorial Western Countries

While WCPO fleets are likely to see their business suffer from the trend, it is predicted that improved fishing conditions will prevail in the EPO.

Allain reiterates that it will obviously have an influence on catches in the WCPO, but also the on-shore industry-related facilities, including canneries reliant on supply from the region.

In turn with the displacement of tuna from the currently rich WCPO zone, the Eastern Pacific will likely notice increased abundance of tuna stocks. And in the long term this could see the region become the major tuna catching ground globally, if climate change impacts continue.

Some boatowners may have already seen a shift, or are expecting the looming changes, realizing the benefit of having their seiners registered to both the WCPFC and the IATTC. This allows them to choose which catching ground to pursue in light of the fishing conditions.

Such activity has been observed most notably from the United States purse seine fleet in recent years. Around 10 Tri Marine-owned seiners started fishing in the EPO in 2015, pushed by disrupted PNA access and also El Niño conditions that were producing strong catch rates in the EPO.

To date, they continue to fish in both ocean regions, depending not only on the current fishing conditions in each, but also on conservation measures like the WCPO FAD ban and the EPO purse seine closure.

Boatowners that have the benefit of being registered to both areas could therefore be the biggest winners if and when SPC’s predictions start to more obviously show themselves. As well as this, the fleets that are most active in the EPO, like the Ecuadorian and Mexican flagged fleets, could see substantially boosted catches.

If this is the case, and the displacement occurs at much stronger rates in years to come, it will see tuna stocks moving out of EEZs, where countries can make revenue off their resources, and into the high seas, where current conservation measures are weaker. Also, high seas access is free for all vessels, meaning that no countries will be making money off the increased fishing effort.

The impact of this on the small island Pacific nations of the PNA and beyond, would be catastrophic if the SPC predictions prove correct. They could lose a resource that provides their economic backbone. At the same time, distant water fishing nations setting their nets on the boosted stocks in the EPO, under free high seas access, will likely be the ones to benefit most substantially from the shift.

But the influences will also come in terms of the tuna market of course; the major tuna catch volumes that are currently netted in the WCPO are landed in their majority in Bangkok, the largest tuna production hub globally. However, in recent years, the presence of other production centers like Ecuador’s Manta and Mexico’s Mazatlán in the tuna industry has become even stronger.

With increased catches expected to prevail in the Eastern Pacific Ocean, and vessels likely to send their raw material to the nearest major ports, locations like Manta and Mazatlán could therefore grow in importance on a global scale. This in turn would lessen the importance of the biggest WCPO processing sites, not just Bangkok, but also General Santos City and PNG.

However, for the EPO fleets and canneries to reap the benefits of an environmental impact that will have disastrous implications on parts of the globe, could be bittersweet. It is likely that even if EPO fleets see stronger catches for some time, much stricter conservation measures will need to be implemented by the IATTC on the high seas, to make sure that potentially increased fishing does not threaten the long term sustainability of these stocks.

But while it is probable that many boatowners will be keen to switch their operations from the WCPO to the EPO if these changes start to occur, current measures in place could substantially limit this.
A source told Atuna that both RFMOs – the WCPFC and the IATTC – have implemented capacity resolutions. This means that they have a limit on the number of vessels each country can register to each RFMO. As well as this, the EPO purse seine closure was extended for the first time this year, to relieve pressure on major tuna populations and, if conservation measures keep strengthening, the chances for the fleet to benefit from more abundant stocks could be minor.

According to Allain, the impacts of climate change on tuna populations are already occurring and both the displacement of the stocks and stratification of the water column are showing their signs. Notably increased catches in the EPO this year may go some way to support this, as well as reports of slow catch and short supply in the Western Pacific. However, longer term data will need to be assessed before any clear conclusions can be drawn.

There is some opportunity for the tuna industry to avoid this predicted fate, but it will take concerted global effort, not just from our sector, but from the major nations worldwide, to reverse the effects. The model used by SPC relates to “business as usual”, Allain says. This is based on the world continuing to emit greenhouse gases at the current rate, and if we manage to decrease our emissions dramatically as soon as possible, she thinks the impact expected for the tuna industry could possibly be mitigated.

Recent global gatherings indicate that the recognition and concern around this major environmental threat is growing, and with all but one nation joined together to work out the efforts needed to combat it, there are positive signs of potentially slowing down the impacts.

From Pacific island nations in the WCPO, the push will likely be even stronger, not just for the sakes of their rich tuna and fishery resources, but for their land and their general existence, with catastrophic global warming effects already starting to show.

Over the next 100 years, if climate change continues at today’s pace, the rising sea levels that are coming with it could completely engulf some small island nations. And Kiribati, arguably the richest tuna resource owner in the world, is expected to be the first to go.