This week our Marine Biologist, Jess, discusses one of the biggest threats to marine life; ghost nets, and how this deadly marine litter is affecting the turtles in our Atoll Marine Centre.
Whilst the majority of the turtles we receive at Atoll Marine Centre are illegally kept hatchling or juvenile Green Turtles, this year we’ve received record numbers of injured Olive Ridley turtles. At the beginning of December 2016 a fisherman found a large Olive Ridley sea turtle caught in a ghost net, with deep lacerations around her fin, which ended in an amputation. We named her Nema; she was the first of 13 injured Olive Ridley’s arriving at Atoll Marine Centre within the following 8 months.
A timeline of the 13 injured turtles we have received in the last 8 months
Ghost nets are fishing nets that have been left or lost in the sea. They have become one of the greatest killers in the ocean and now pose a serious threat to marine life all over the world. Hundreds of kilometers of fishing nets are abandoned annually and can take up to 600 years to degrade. It’s estimated that these fishing nets make up a whopping 10% (640,000 tonnes) of litter in the ocean, leading to devastating impacts on the environment. In the Maldives, fishing nets are illegal, with only pole and line methods utilized by fishermen, however when the monsoons change, an influx of ghost gear washes through from surrounding countries such as Pakistan, India, and Sri Lanka.
The shocking injuries Stitch received from a ghost net
When discarded, abandoned or lost at sea, nets become caught on coral reefs, smothering and destroying coral, wiping out whole ecosystems while they move in the current. Some nets drift further into the open ocean continuing to catch fish, which is known as ‘ghost fishing’. This is often where the nets catch other marine mammals, seabirds and turtles ,who get trapped and die. With the weight of the animals the nets sink to the seafloor where scavengers feed on the carcasses, the weight is then lifted, and the net floats back into the water column for the cycle to start again and continue to cause further damage.
The destructive Ghost Fishing Cycle. (Source: Olive Ridley Project)
There are many ‘ghosts’ in the marine environment including overfishing and acidification, connected with greenhouse gases, and the increase of anoxic ‘dead zones’ as a result of run off filled with fertilizers. Ghost gear is part of the array of challenges which must be addressed urgently to protect the ocean from anthropogenic impacts.
8 out of the 13 turtles we’ve received have had fins amputated and 9 out of 13 have been suffering from buoyancy syndrome, injuries directly caused from ghost nets. When caught in the ghost nets turtles often inflate themselves with air as a stress response, in order to protect themselves from drowning. This air then gets trapped between the carapace (shell) and the organs, causing them to float. 9 months later, and Nema, our first Olive Ridley, is still very buoyant and cannot dive. Although she is healthy, we have to wait for her to naturally release the air to release her, as she would currently starve on the ocean surface if she were let back into the ocean. Some of our turtles have lost their buoyancy overnight and some have taken months, unfortunately the reasons behind their recovery is still a mystery. We are currently taking Nema out into the sea, giving her more opportunities to practice her diving, and we are seeing promising improvements, so we hope it won’t be long now!
Nema during one of her diving rehabilitation sessions in the ocean
We have received turtles up to 30kg, a size bigger than our centre was designed to accommodate. Many have been transferred to and from the Olive Ridley Project and we are now building bigger tanks more suited to their needs (if you wish to help donate to this cause, please visit our Go Fund Me page). We’ve also began re-purposing ghost nets we find and have started selling keyrings and bracelets in our gift shop with bowls and animals next on our to-do list!
Don’t forget – 80% of ocean rubbish comes from land! Here’s a quick picture of how long it takes some general household goods/common marine debris to decompose. Please think twice about purchasing single use plastics and always remember to reduce, reuse and recycle.
By Jess Kalisiak