Something fishy on the high seas

July 25, 2018

Halifax, NS - It could be considered the global CSI for high seas fisheries. In two new groundbreaking studies, researchers from Dalhousie University, Global Fishing Watch and SkyTruth have applied cutting-edge technology to map exactly where fishing boats may be transferring their catch to cargo vessels at sea.

Known as transshipment, the practice increases the efficiency of fishing by eliminating trips back to port for fishing vessels. However, as it often occurs out of sight and over the horizon, it creates major challenges, including enabling illegal, unreported and unregulated (IUU) fishing.

"Because catches from different boats are mixed up during transshipment, we often have no idea what was caught legally and what wasn't," said Kristina Boerder, a PhD student in Dalhousie University's Department of Biology and lead author on the Science Advances paper, published this week.

Transshipment can also facilitate human rights abuses and has been implicated in other crimes such as weapons and drug trafficking. It often occurs in the high seas, beyond the reach of any nation's jurisdiction, and where policy-makers and enforcement agencies may be slow to act against an issue they cannot see. By applying machine learning techniques to vessel tracking data, researchers are bringing unprecedented transparency to the practice.

"So far, this practise was out of sight out of mind, but now that we can track it using satellites, we can begin to know where our fish truly comes from," says Dr. Boris Worm, a Marine Biology Professor in Dalhousie's Faculty of Science, and co-author of the Science Advances paper.

By using the same sophisticated machine learning technology and satellite identification systems originally developed to map the global footprint of fishing from space, researchers at SkyTruth and Global Fishing Watch were able to track the behavior of refrigerated cargo vessels (reefers); determine when and where transshipment occurs; and which fleets are most involved in this practice. These basic findings and the associated dataset were published this week in the journal Frontiers in Marine Science.

Researchers at Dalhousie University, collaborating with SkyTruth, built upon this work to identify for the first time the fishing vessel types and fisheries most involved in transshipment, as well as what proportion of high seas catch is transshipped versus landed directly. They also traced seafood supply chains for tuna fisheries in the Indo-Pacific. Together these publications provide the most complete, global view of transshipment to date and demonstrate what is possible through interdisciplinary collaboration.

"These unprecedented studies serve as examples for how big data experts, NGOs and academics can come together to address critical, global challenges that were up to now too large, too complicated, or simply too hard to observe", says Nate Miller, a Data Scientist at SkyTruth and author on both papers.

Between 2012 and the end of 2017, the Dalhousie team observed 501 reefers meeting with 1856 fishing vessels in 10,510 likely transshipment events worldwide, with trawlers (53%) and longliners (21%) involved in the majority of cases. They discovered that although transshipment is occurring in all oceans and across 42 Exclusive Economic Zones (EEZ), it is more common in distinct hot spot areas, including off West Africa, Russia and in the tropical Pacific.

"I think this really touches everyone who eats fish, and at a time when people are more concerned about where their food comes from, this knowledge will be really helpful," added Boerder. "A better understanding of what happens to seafood before it reaches our plates will hopefully help consumers buy legally and sustainably caught fish without a 'fishy' past."

The research also highlights novel ways to trace seafood supply chains and identifies priority areas for improved trade regulation and fisheries management at the global scale. The studies mark the first step towards better visibility into the often shadowy practice of transshipment. An improved understanding of transshipment can help governments, NGOs and academia to support both regional and global efforts to strengthen monitoring and enforcement to eliminate illegal fishing.

"I believe we are entering a new age of fisheries management, where for the first time in our history we can truly see what goes on beyond our shores," said Dr. Worm.
"Identifying global patterns of transshipment behavior" is freely available in Frontiers in Marine Science. "Global hot spots of transshipment of fish catch at sea" is available in Science Advances. Download supporting visual assets to use with the release here.

Dalhousie University

Founded in 1818, Dalhousie University is Atlantic Canada's leading research-intensive university and an international ocean sciences hub. The Lab of Senior Author Boris Worm focuses on how marine biodiversity is distributed across the globe, how it changes over time, and how its loss can be prevented. Fishing can cause major impacts on marine biodiversity, and together with Global Fishing Watch, the Worm lab is conducting studies into the interactions of fishing with marine protected areas, biodiversity hotspots, migratory species, and the global effects of fishing on biodiversity.

Global Fishing Watch

Global Fishing Watch is an international non-profit organisation committed to advancing the sustainability of our oceans through increased transparency. By harnessing cutting edge technology, our mapping platform allows anyone to view or download data and investigate global fishing activity in near real-time, for free. Global Fishing Watch was founded in 2015 through a collaboration between Oceana, SkyTruth and Google. Our work is made possible thanks to the support of our funding partners and technology and data providers.


If you can see it, you can change it. SkyTruth hopes this illustration of global fishing activity, made available on a public map for the first time, will prompt people to ask questions about how well our ocean and its living resources are being managed and protected. Founded in 2001, SkyTruth's mission is to share the view from space in order to motivate people to protect the environment. We're driven by the belief that better transparency leads to better management and better outcomes for people and the planet. To learn more, check out what we do and how we work at

Global Fishing Watch

Related Fisheries Articles from Brightsurf:

Assessing El Niño's impact on fisheries and aquaculture around the world
New report presents the main regional consequences caused by the five types of the climate pattern.

Dissolved oxygen and pH policy leave fisheries at risk
In a Policy Forum, ''Dissolved oxygen and pH criteria leave fisheries at risk'' published in the April 24 issue of the journal Science, Stony Brook University's Dr.

Fisheries management is actually working, global analysis shows
Nearly half of the fish caught worldwide are from stocks that are scientifically monitored and, on average, are increasing in abundance.

Meeting the challenges facing fisheries climate risk insurance
Insurance schemes with the potential to improve the resilience of global fisheries face a host of future challenges, researchers say.

Healthy mangroves help coral reef fisheries under climate stress
Healthy mangroves can help fight the consequences of climate change on coral reef fisheries, according to a University of Queensland-led study.

Study champions inland fisheries as rural nutrition hero
Researchers from MSU and the FAO synthesize new data and assessment methods to show how freshwater fish feed poor rural populations in many areas of the world.

For global fisheries, it's a small world after all
Even though many nations manage their fish stocks as if they were local resources, marine fisheries and fish populations are a single, highly interconnected and globally shared resource, a new study emphasizes.

New study maps how ocean currents connect the world's fisheries
It's a small world after all -- especially when it comes to marine fisheries, with a new study revealing they form a single network, with over $10 billion worth of fish each year being caught in a country other than the one in which it spawned.

Federal subsidies for US commercial fisheries should be rejected
A pending rule change proposed by the US National Marine Fisheries Service would allow the use of public funds to underwrite low-interest loans for the construction of new commercial fishing vessels.

Sustainable fisheries and conservation policy
There are roughly five times as many recreational fishers as commercial fishers throughout the world.

Read More: Fisheries News and Fisheries Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to