Global fisheries need monitoring, but satellites alone won’t help

Almost 80 million tonnes of marine animals are taken from the ocean annually for consumption. Global demand for seafood continues to increase, but it is stretching the ocean’s resources. Scientists estimate that as much as one-third of fished stocks are exploited at biologically unsustainable levels. Which means there is a strong urge to monitor fishing on a global scale.

Bird's eye perspective on a fishing boat

A necessary first step towards improving the sustainability of fisheries is improving our knowledge of global fisheries; for instance, who is doing the fishing, where they are operating, and how much and what species they catch.

“It is becoming increasingly urgent to improve ocean surveillance as nations grow more aggressive in their hunt for disappearing fish stocks..”

Improved fisheries monitoring is essential for healthy marine ecosystems, equitable food provision, and preventing human rights abuses.

The satellite data revolution

Despite the seemingly obvious opportunity to use satellites for monitoring and surveillance of the ocean, current systems have lagged behind their counterparts on land. Now, we are finally making progress with satellite-based technologies for monitoring global fishing activity.

Recent initiatives like Global Fishing Watch provide open-source data on global activity of ships equipped with satellite transponder equipment, but these exciting new maps can distract us from the many boats the satellites can’t see because they don’t have satellite transponder equipment.

“We need more strategic planning to address the undetected vessels and activities that make seafood so untransparent.”

Is it really that hard to detect a ship as long as 15 school buses?

A lot of fishing still takes place from wooden boats powered by sails or oars but at the other end of the spectrum, wartime technologies were redirected to develop industrial fishing fleets into high-tech fish-hunting machines. These ships use sonar to detect fish all the way down to the ocean floor and are equipped with mechanized fishing gears that can extend many kilometres behind the boat and scoop, entangle, or hook any animals that pass by. Smaller supplier vessels often attend these “motherships” at sea, so they are rarely forced to enter ports where it is easier to inspect them.

“Thus, it is surprisingly difficult to trace fishing boats even if they are massive.”

Satellites help… as long as there is co-operation

Satellites offer a promising solution, but satellite data are affected by cloud cover, solar light input angle, and how often the satellite passes overhead.

The two main satellite-based technologies for tracking ships are the Automatic Information System (AIS) and Vessel Monitoring System (VMS).

Both are cooperative systems where a transponder is installed on a vessel and communicates with the shipboard Global Positioning System (GPS). AIS is an open, non-proprietary system with international standards that usually transmits continuously, but it can easily be turned off or hacked. VMS is more difficult to tinker with, but it’s proprietary and has high barriers to data access because the country or shipowner has to hand over the data. More about ships and satellites here.

How does science help?

Despite the limitations of current systems, scientists are making real progress in combining information from AIS and VMS with digital data technologies to crack down on illegal, unreported, and unregulated fishing (IUU).

For example, this study by Ford et al. (2018) developed a spatial statistical model that predicts when vessels are intentionally disabling their AIS transmitters, which typically signals that they are conducting some sort of illicit activity. Souza et al. (2016) developed a similar model that also works from AIS data to predict when a vessel is fishing and what type of fishing is taking place.

What about the little boats?

There is huge opportunity to capitalize on satellite technologies, but industrial vessels pinging information from their AIS or VMS are the low-hanging fruits of ocean surveillance.

Many fishing vessels do not carry satellite transponders and are therefore invisible to data providers such as Global Fishing Watch.

“One of the major “dark spots” in global ocean observation is the Indian Ocean, which has massive “small-scale” fishing sectors that are subject to very little oversight even though many now operate at industrial scales.“

There are more than two dozen fishing countries in the Indian Ocean, not including foreign fleets such as China, Taiwan, and Spain. Many countries are severely limited in their ability to manage fisheries (e.g. Somalia, Yemen).

While these fisheries are not necessarily operating illegally, often because they have minimal regulations to comply with in the first place, small-scale fisheries can have a tremendous impact on marine ecosystems.

What else can we do?

Even if satellite-based technologies improved to the point where every single canoe could be detected, that still only addresses the starting point in the seafood supply chain.

The primary responsibility for monitoring and managing fisheries typically lies with the country where the vessel is flagged and, to a lesser extent, the jurisdiction of the waters where the fishing takes place. There are obvious loopholes in this system, for instance, “flags of convenience” and governance of the “High Seas” — the areas beyond national jurisdiction.

“Additionally, the burden of monitoring fisheries is placed on the supply side (the fishers and fishing countries) leaving the demand side (seafood distributors and consumers) free of any binding obligations to contribute to this difficult task.”

No single solution is going to clean up global fisheries, but fortunately, scientists and managers are expanding on many different technologies from a variety of industries and transferring these developments to fisheries contexts. See this article for an overview of the developments that are most relevant to fisheries’ problems.

Meanwhile, we need to identify the regions and fisheries that are the most urgent gaps to fill in global fisheries monitoring. More coordinated efforts from governments, fishing and seafood companies, non-governmental organizations, and consumers are essential to improve this complicated industry.

Anyone who benefits from fisheries — by eating seafood, eating animals or crops fed or fertilized with fish oil, or by working in an industry related to recreational or commercial fishing — has a direct interest in improving the management of these valuable resources.

Leslie Roberson

by Leslie Roberson

Ocean explorer & PhD Candidate at the University of Queensland, Brisbane, Australia. She identifies opportunities to reduce fisheries impacts on threatened species.