Climate change is causing significant shifts in marine ecosystems, particularly around Greek waters.
Rising temperatures are driving invasive species such as fish and jellyfish to migrate from warmer regions like the Indian Ocean and the Pacific Ocean to the cooler Mediterranean Sea.
These migrations are facilitated by pathways such as the Suez Canal, bringing new environmental challenges to the Mediterranean region.
One of the most problematic species is the bluespotted cornetfish (Fistularia commersonii). This invasive fish has wreaked havoc in the Mediterranean by preying primarily on the eggs of native fish species, significantly disrupting local marine life.
Its rapid spread and high reproductive rate have positioned it as a major threat, especially in the eastern Mediterranean, altering the delicate balance of marine biodiversity.
Climate change and its rapid effects
March 2024 marked a significant milestone as one of the warmest months in recorded history.
According to the EU Copernicus Climate Change Service, temperatures were 1.68 degrees Celsius (35 degrees Fahrenheit) higher than pre-industrial times.
This recent warming trend is not just a statistical anomaly. It represents the tenth consecutive month of record-high temperatures, a concerning pattern for marine ecosystems.
Warmer waters in regions such as the Aegean Sea have become a new norm.
Marine scientists point to these rising temperatures as a critical factor in the movement of marine life.
A particular concern is the increase in marine species migrating from the Red Sea through the Suez Canal into the Mediterranean.
This migration, known as the Lessepsian migration, is significantly altering the Mediterranean biosystem.
The typically cooler waters of the Aegean Sea warming up serve as an invitation for these invasive species to thrive.
This phenomenon illustrates the profound impact climate change has on marine biodiversity, prompting shifts in species distribution and ecosystem dynamics.
Invasive fish in Greek waters
In recent years, the waters around Greece have become new habitats for invasive fish species from the Red Sea and Indian Ocean.
Notable among these newcomers are the lionfish and the silver-cheeked toadfish, both known for their venomous nature and potential threats to native marine life and humans.
The lionfish, originating from the western Indo-Pacific region, is a formidable predator. This species competes with native fish like snapper and grouper for resources, disrupting the local ecosystem.
Additionally, lionfish prey on vital species such as algae-eating parrotfish, leading to unchecked seaweed growth on reefs, which further destabilizes the marine environment.
Physically, lionfish can reach up to 35 centimeters (14 inches) in length.
They are identifiable by their distinctive venomous fins. Their dorsal fin comprises thirteen long, stiff spines and nine to eleven soft rays, while the anal fin features three long spines and six to seven soft rays.
The silver-cheeked toadfish, known scientifically as Lagocephalus sceleratus, has also been making its presence felt in Greek seas.
Named for their resemblance to toads, these fish belong to the Batrachoididae family, which means “frog-shaped” in Greek. They are particularly dangerous due to their tetrodotoxin content, a potent poison found in their ovaries, skin, muscles, and liver, serving as a defense mechanism against predators.
The mating calls of toadfish, which alert dolphins to their presence, further complicate their relationship with the ecosystem.
Despite their toxicity, which deters many predators, invasive toadfish populations are swelling, posing a continuous challenge to marine life balance.
Both species underscore the drastic impacts of climate change and shifting marine environments.
Environmental shifts facilitate the spread of these invasive species, bringing unforeseen challenges to the biodiversity of Greek waters.
Health Hazard
Pufferfish, also known as blowfish or bubblefish, belong to the Tetraodontidae family and are famously toxic.
Although a delicacy in Japan and China, their consumption can pose serious health risks.
Pufferfish defend themselves by inflating their elastic stomachs with water, turning into an almost inedible ball. Some species have spines on their skin as an additional line of defense.
Despite these protective measures, they are still hazardous.
Eating these fish can result in severe health consequences like paralysis, heart failure, and respiratory failure, which can be fatal.
On the islands of Crete and Kalymnos, there have been cases where aggressive blowfish have sent swimmers to hospitals for surgery after encounters in the water.
Health risks from pufferfish include:
- Paralysis: Can affect muscles and organs.
- Cardiac Issues: Heart failure.
- Respiratory Problems: Potentially leading to death.
- Surgical Interventions: Required after aggressive encounters.
Blowfish also harm the environment by damaging fishing nets, compounding the economic and health challenges they pose.
Their presence in new waters, driven by changing climate conditions, continues to be a cause for concern.
