Everywhere mankind goes, we leave a footprint – a trace of our presence.
People used to believe that the oceans were ‘too big, and too vast’ for our footprint to mean anything. But boy were we wrong.
Marine debris litters our seas, from the polar Arctic to the sunny Caribbean. And it’s not just plastic straws that are the issue – the vast majority of debris in our oceans comes from the fishing industry.
So what exactly is marine debris?
Marine Debris (noun): any persistent solid material that is manufactured or processed and directly or indirectly, intentionally or unintentionally, abandoned into the marine environment.
Single-use plastics, fishing gears, shipwrecks, and microplastics are all different forms that marine debris can take – each harmful in their own unique way.
One specific type of marine debris that we’ll discuss today are Fish Aggregating Devices (FADs for short).
What Are Fish Aggregating Devices?
Fish aggregating devices are artificial floating structures in the sea, designed to attract pelagic fish.
The open ocean is like an endless blue desert – filled with animals that can travel vast distances in search of shelter and food. Any structure floating at sea can become an oasis in these oceanic deserts by creating habitat for life to cling to.
FADs are helpful to open-ocean fishers because they help draw in predators from miles away. They come in a variety of shapes and sizes, and can be made of anything from fishing rope to a buoy!
These artificial structures are designed to mimic natural structures that float across the open ocean, creating habitat for marine life. Sargassum seaweed is one such example that forms a natural open ocean habitat while traveling across the Atlantic Ocean.
FADs can be grouped into two categories:
- Static FADs which are anchored to the bottom of the sea using a weight.
- Free-floating FADs which are not anchored and float about the open ocean.
How exactly do Fish Aggregating Devices work?
Marine plants, small crustaceans and mollusks are attracted to FADs because they provide a solid structure to settle on. These pioneer species are food for other fish wandering the sea, and within no-time smaller fish become attracted to the floating FAD. Predatory fish wandering the sea eventually join the party as they’re attracted to the smaller fish that accumulate here. Thus, an entire ecosystem like the one in sargassum is created.
Fishers use FADs to target specific predatory species: mainly tuna, billfish and dolphin fish.
They deploy these structures in the ocean, equipped with a tracking buoy (image below), and let them soak long enough for life to accumulate.
Problems with FADs – A Danger to Sea Turtles and Marine Mammals
Fishers created and designed FADs for a specific purpose: to target high-value species of marine life.
Unfortunately, these devices can negatively impact other non-target species that gather around them.
Entanglements are the biggest issue that sea turtles face from FADs. Equipment like nets, ropes and lines used to set up FADs can entangle turtles when they come into contact with them. Sea turtles can even injure themselves trying to escape the equipment.
Similarly, marine mammals cam also become entangled by nets, ropes and lines used to construct FADs. Static FADs specifically pose a problem because they have an anchor line which can entangle and/or injure larger marine the mammals.
Like humans, sea turtles and marine mammals can’t breathe underwater, so they need to resurface and receive air. Entanglement in a FAD can lead these animals to drown.
One adverse affect that FADs can even have on species like Tuna, is that they can change the distribution of these animals by leading them into different areas where FADs are present.
Fish Aggregating Devices in the Caribbean
By nature, FADs are easily lost at sea. Whether it be extreme weather, or an encounter with a boat propeller – once lost at sea FADs can travel extreme distances.
The Caribbean and Florida have recently begun to encounter this issue, as FADs used by the Purse-Seine Tuna Fishery off West Africa have been documented washing ashore.
These FADs are traveling across the ENTIRE ATLANTIC OCEAN!
That’s a massive distance, and it shows how this is truly a global marine debris issue. Unfortunately, there are few (if any) regulations put in place globally to regulate the use of FADs in commercial fisheries.
What Can I Do To Help?
If you see a FAD washed up on a beach in The Caribbean or Florida, please note:
- The date,
- Buoy serial number
- And take a photo
And send your report to Nikola Simpson at [email protected]
Article written by Micaela Small and Brian Yurasits, The TerraMar Project