Pacific island countries are behind a study to gauge the amount of plastic waste that is dumped at sea by tuna fishing vessels working in the Western and Central Pacific Ocean (WCPO).

The study is also judging how well vessel operators are complying with the main rule to control marine pollution in the WCPO. This is the Western and Central Pacific Fisheries Commission (WCPFC) conservation and management measure (CMM) 2017-04. The rule, which came into effect on 1 January 2019, prohibits the dumping of any plastics into the ocean.

The study into the disposal of plastic waste has been commissioned by the Oceanic Fisheries Management Project (OFMP2) of the Pacific Islands Forum Fisheries Agency (FFA). It is preliminary to FFA member considering possible ways of strengthening CMM 2017-04.

FFA has noted that, despite WCPFC’s “excellent step towards curbing drastic levels” of plastic marine pollution, “the reality of current plastic disposal methods is in stark contrast to the intention of the measure”.

The Chief Technical Officer of the OFMP2 for FFA, Hugh Walton, said that, although the passing of CMM 2017-04 was a “landmark win” for FFA members, it had not necessarily equated to a decrease in the amount of waste dumped at sea. Countries had had more than a year from the adoption of the CMM in 2017 to consider the means needed once it came into force.

Clause 2 of the CMM states that: “CCMs shall prohibit their fishing vessels operating in the WCPFC Convention Area from discharging any plastic (including plastic packaging, items containing plastic and polystyrene) but not including fishing gear.”

Mr Walton said most of the other clauses did not prohibit actions, but merely encouraged signatories to prohibit their vessels from dumping waste at sea. And there was no mechanism to enforce clause 2.

“We hope this study will point to ways we can align the intention and the reality of waste disposal,” Mr Walton said.

One of the three consultants doing the study is fisheries adviser Francisco Blaha, who worked on commercial fishing vessels for many years. He has teamed up with Robert Lee, who also has a lot of experience on fishing vessels, and Alice Leney, a hands-on expert in waste disposal in the WCPO.

“We all come from operational experience,” Mr Blaha said.

“We believe it is important that we understand what it is like working in the industry. This is partly because we can’t go onto the vessels at the moment so we have to do a desktop study only.

“But also because there is this whole belief that fishers dump waste at sea by pure malice. We know what it’s like on the boats and we know that’s not true.

“People do things because there are incentives to do it that way, or because they don’t know a better way. Space is always a problem on fishing boats, so we need to consider what the main sources of plastic waste other than fishing gear, how much plastic waste is produced, and what is currently done with it in different fleets and jurisdictions. Then we can think about better ways to deal with plastics. How can people be incentivised, with the limited options of surveillance that exist at the moment? That, in a nutshell, is what we are investigating.”

On a purse-seine tuna fishing vessel, buoys, netting, and used plastic salt bags. Photo: Francisco Blaha.
Once emptied of their salt, plastic salt bags are often re-used in the construction of fish-aggregating devices. Photo: Francisco Blaha.

The study team is building on what is known about the disposal of waste plastics at sea from a 2018 study commissioned by FFA and a 2017 study from the Secretariat of the Pacific Regional Environment Programme.

“We already have quite a lot of problems with rubbish. If we’re going to take fishing vessel waste back to land, this will have a big impact on the rubbish on the islands. Other than Suva, all the other dumps are saturated: there is no more room. The highest point of Marshall Islands is the rubbish dump.”

The study team will look to quantify how much plastic waste is generated in the exclusive economic zones of FFA members and in the nearby high seas, and group it by sources such as vessel size, gear used (longline or purse seine) and the number of crew members. They will look at estimate volumes produced, disposed of overboard and brought ashore. They will investigate the impact in the ports that attract a great deal of fishing traffic of disposing of waste there.

Then they will summarise the mechanisms for disposal that could be applied, and recommend strategies and practices that will lead to better application of the present regulatory frameworks.

“If we look by type of vessel, the area where we have the biggest volumes is longlining, as there are numerous fleets. But also purse-seine is quite remarkable,” Mr Blaha said.

“There is only 5% observer coverage on longliners, but from what we know, about 60% of what goes into the water is plastic. On purse-seiners, with 100% observer coverage, it’s 37%.

“We have identified that the main source of plastic waste for longliners is the liners in the bait boxes, and for purse-seiners, it’s the salt bags.” (Salt is used to make a brine that is used in freezing the fish.)

He said it was difficult to estimate the volume of these items, because there were so many variables to take into account.

“Let’s look at longlining. How many hooks get soaked into the ocean? There were over 800 million of them in the WCPO in 2019. Then we work out bait size and weight, and adjust for the type of tuna being caught. For tropical tunas, you may be baiting 100 hooks per box, but for albacore it may be 150 hooks, so the number of boxes used varies,” Mr Blaha said.

“With the salt bags in the purse-seine fleet, it is complicated by cultural variations in the ways people operate, for example in how the brine is prepared or how much you reuse the brine, or if you flood wells for unloading.

“With crew waste, we look at crew-generated plastics: food wraps, cups, water bottles. The totals depend on the number of crew, not just on the gear on the vessels,” he said.

Volumes were less difficult to calculate when vessels came into ports than if they stayed on the high seas, although there were still many variables to consider.

“It’s way more complex that we ever thought it would be – and we knew it would be complex,” Mr Blaha said.

“This study is the first step. This is an area that is only going to grow. It needs to be fine-tuned in the future. But for this step, we wanted to make sure that whoever reads this knows we considered as much as we can for the estimates, that this is not a back-of-the-envelope estimate.

“How any recommendations can be enforced is always the big question in anything related to fisheries.”

One way to verify compliance with CMM 2017-04 might be to strengthen the capture of marine pollution data using the electronic monitoring cameras on board that are increasingly being used on fishing vessels to help monitor compliance with other fishing rules.

The team was also exploring an idea that visitors to national parks in countries such as New Zealand and Australia are familiar with: that you take out with you what you brought in.

“If the carriers bring the bait, bring the salt bags, they can take them away again, as carriers may have incinerators on board, or at least more space. We are also exploring the idea of bonds: they get their bond money back when they show that the rubbish has gone back with them,” Mr Blaha said.

As with a study FFA has commissioned on illegal, unreported and unregulated fishing, a draft of the marine pollution report will be discussed at the annual FFA Monitoring, Control and Surveillance Woking Group meeting at the end of March, with the final report to be presented to the annual meeting of the Forum Fisheries Committee in May.