Top 5 Threats to the Mediterranean Sea and How We Can Combat Them

Wednesday, 03 Jul, 2024

The Mediterranean Sea, renowned for its rich biodiversity, is home to over 17,000 marine species, with up to 30% of them unique to the region. Despite its ecological importance, the Med is facing severe challenges. According to the UN Environment Programme (UNEP), approximately 75% of its fish populations are overexploited, and almost half of its top predators -- including marine mammals -- have been lost since 1950. Here are five of the biggest threats confronting the Med and how we are combatting them.

Crew taking apart the illegal fishing gear pulled onto the Sea Eagle. Photo by Claire Foster/Sea Shepherd.
Sea Shepherd crew holding some of the longline and hooks retrieved in the Mediterranean Sea. Photo Helena Constela/Sea Shepherd.
A FAD and fishing net floating in the water. Photo by Jacopo Casati/Sea Shepherd.

1. Fish Aggregating Devices

Illegal Fish Aggregating Devices (FADs) pose a significant threat to the Mediterranean Sea, contributing heavily to overfishing and disrupting marine ecosystems. FADs are man-made structures designed to attract fish. They typically consist of floating materials, such as palm leaves or plastic tanks, which provide shade and create a habitat where fish congregate. The floating part is anchored to the sea floor with long lines made of non-biodegradable materials like polypropylene.

Once a large number of fish have aggregated under a FAD, fishermen encircle the area with nets, capturing all the fish present. This indiscriminate fishing method leads to the capture of both target and non-target species, including endangered marine wildlife and juveniles that have not had the chance to reproduce, thus severely impacting fish populations and biodiversity.

In addition to overfishing, FADs are a major source of plastic pollution. The non-biodegradable materials used in their construction stay in the ocean indefinitely. These materials can entangle marine animals like turtles and whales, leading to injury or death, and contribute to the broader issue of plastic pollution as they degrade into microplastics.

Sea Shepherd’s campaigns have uncovered the extensive use of illegal FADs in the Mediterranean. For instance, in 2018, Operation Siso confiscated 52 illegal FADs and 100 kilometers of polypropylene line within just 178 hours. Over the years, the efforts have intensified, with Sea Shepherd volunteers removing a record 237 illegal FADs in 2021 alone. This relentless effort has highlighted the scale of the problem, with estimates suggesting that over 10,000 illegal FADs are anchored annually in the southern Tyrrhenian Sea, contributing significantly to marine pollution and ecosystem degradation.

A 3m-long blue shark in an illegal driftline is still alive and released on Operation Siso. Photo by Flavio Gasperini/Sea Shepherd.

2. & 3. Drift Nets and Longlines

Drift nets and longlines are notorious for their indiscriminate and destructive nature, ensnaring a wide variety of marine life, including protected species such as sperm whales, dolphins, sea turtles, and sharks. Despite being banned, these fishing methods are still prevalent in the Mediterranean, posing a severe threat to marine biodiversity.

Also known as "walls of death," driftnets are large fishing nets that can stretch for several kilometers. They are left to float freely in the open sea, held up by buoys. Fish and other marine creatures swimming into these nets become entangled in the fine mesh, unable to escape. This method is highly effective in capturing large quantities of fish but often results in a high level of bycatch of unintended species, such as marine mammals, turtles, and even seabirds. The trapped animals struggle to free themselves, often leading to exhaustion, injury, and death. Drift nets were banned globally in 2003 due to their devastating impact on marine ecosystems, but illegal use persists.

Longlines consist of a central fishing line, which can be up to several kilometers long, with shorter lines branching off it. Each branch line is equipped with baited hooks designed to attract fish such as tuna and swordfish. While effective for targeted fishing, longlines also pose significant risks to non-target species, especially sea turtles and seabirds. When left unattended for extended periods, longlines are particularly dangerous because they continue to catch and kill marine life indiscriminately.

Sea Shepherd's operations have consistently targeted these illegal fishing methods. For example, in 2019, our volunteers intercepted and confiscated a 5-kilometer-long illegal drift net in the waters around the Aeolian Islands. Similarly, in 2022, Operation Siso’s volunteers removed 130 kilometers of main line and 2,000 hooks from illegal longlines off the Calabrian coast. Thanks to our efforts, no whales were found entangled over several years.

Octopus freed from a trap by crew on the Sea Eagle. Photo Willem van der Heever / Sea Shepherd Global

4. Octopus Pots

Italy’s Tuscan coast is known for octopus fishing using the “pot” technique: devices made of black plastic pots attached to nylon cables up to 2 kilometers long. These pots, disguised on the muddy seabed, look like safe shelters for the octopuses, where they take shelter and lay eggs. The fishermen just need to pull up the line and empty the pots each time they find their prey inside. The law limits the number of traps allowed on each boat (i.e. 1250 pots) and forbids leaving fishing gear resting on the seabed year-round. However, these laws are often ignored and rarely enforced.

These illegal octopus pots contribute to the severe overfishing of octopus populations, and disrupts the marine food chain, affecting species such as the endangered Mediterranean monk seal, which relies heavily on octopuses for food.

Sea Shepherd's Operation Siso has been instrumental in combating the illegal use of octopus pots. In 2022, Sea Shepherd confiscated over 7,672 illegal octopus pots from the seabed in the Tuscan archipelago, marking the largest seizure of such traps in the Mediterranean Sea. This has contributed to the years-long efforts made by the conservation community to bring back the Mediterranean Monk seal. Earlier this year the International Union for Conservation of Nature (IUCN) published the good news that the Monk Seals have been reclassified in its Red Data list from “endangered” to the less critical category of “vulnerable”.  

Getting dirty to save marine wildlife: Sea Eagle crew pulled in thousands of illegal octopus pots, checking them one-by-one. Photo Claire Foster/Sea Shepherd.

5. Plastic Pollution

Plastic pollution poses a huge threat to the Mediterranean, impacting marine life through entanglement and ingestion. Abandoned, lost, or discarded fishing gear (ALDFG), commonly known as ghost nets, continues to catch and kill marine life long after it is lost. These ghost nets, along with other marine debris, can be mistaken for food by marine animals, leading to internal injuries, blockages, and starvation.Plastic marine debris also washes up onto beaches where sea turtles lay their eggs, blocking hatchlings from reaching the water.

All kinds of marine debris, including single-use plastic items like cutlery, bottles, and bags, break down into microplastics over time. These particles, less than 5 millimeters in size, pose a significant long-term threat to marine species and ecosystems. Ingested by various marine organisms, microplastics cause physical harm and toxic exposure, and lead to bioaccumulation up the food chain, affecting larger predators and humans. Extremely durable and harder to clean up because of their size, microplastics can persist in the marine environment for decades, continually impacting marine life. The best way to combat them is to prevent plastics from getting into the ocean in the first place.

A baby loggerhead turtle safely reaches the sea. Photo Sea Shepherd Italia.

Sea Shepherd's Direct Action to Protect the Med

Sea Shepherd has several campaigns patrolling on land and at sea to protect the Med, from the Plemmirio Marine Reserve in Sicily and the Aeolian Islands in the Tyrrhenian Sea, to the Tuscan and Calabrian coastlines.

Operation Siso, named after a sperm whale that died entangled in an illegal driftnet with a stomach full of plastic, has been crucial in removing illegal fishing gear and plastic pollution. Since 2018, Sea Shepherd volunteers have worked closely with local authorities, such as the Italian Coast Guard and the Guardia di Finanza, to identify and remove illegal fishing gear and ALDFG, including thousands of kilometers of fishing lines and drift nets from the waters around the Aeolian Islands. Sea Shepherd's record-breaking removal of 237 illegal FADs helped remove materials contributing to microplastics from the sea.

Sea Shepherd's relentless efforts are crucial in mitigating these threats and promoting the recovery of marine life in the Mediterranean. Continued vigilance and enforcement are essential to protect this fragile marine ecosystem. Through collaboration with local authorities, Sea Shepherd continues working tirelessly to protect the Mediterranean Sea and its marine wildlife, preserving its rich biodiversity for generations to come.

Sea Shepherd cut up the ghostnets retrieved on Operation Siso for safe disposal. Photo Lukas Georgio/Sea Shepherd.

Call to Action: Join Us in Making a Difference

Despite many challenges, positive changes are happening thanks to collective efforts. Here are some ways you can help make a difference:

1. Eliminate or greatly reduce fish and other animal products from your diet: Reducing the demand helps decrease overfishing and bycatch.
2. Cut single-use plastic usage: Every bit of plastic avoided is one less piece that could end up in the ocean.
3. Wear our sustainable merch: Directly support life-saving operations with our eco-friendly products.
4. Support our campaigns: Help us in the fight against Illegal, Unreported, and Unregulated (IUU) fishing and plastic pollution in the Mediterranean.

Together, we can ensure a sustainable future for the Mediterranean Sea and its incredible biodiversity. Every action counts, and with your support, we can continue to protect this vital marine environment for generations to come!

The Sea Eagle crew rest after pulling in a boatload of illegal fishing gear. Photo Claire Foster/Sea Shepherd.
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