In our sea, over 1,000 introduced species have been recorded. They represent between 5% and 10% of the total known to live in it. Many adapt well, proliferate rapidly, and cause ecological and socio-economic impacts: these are known as “invasive exotic species.”
Their arrival can occur in various ways, whether accidental (e.g., through transportation, traveling attached to ships or in ballast water) or intentional (introduced for activities such as fishing or aquaculture).
A significant vector is canals, such as the Suez Canal, which have connected waters with very different characteristics.
Globalization has greatly increased this problem, as has climate change, since the rise in water temperature favors species coming from warmer environments.
We have numerous examples of algae, fish, jellyfish, or crabs, among others, that have arrived in our sea and established themselves successfully. One of them is the lionfish (Pterois miles), a venomous and very voracious predator that severely disrupts native fish populations.
“Other proliferating species include the Chinese mitten crab (Eriocheir sinensis), whose life cycle includes both freshwater and marine environments and which has invaded Europe and North America from its native region in Asia, and the Asian seaweed (Undaria pinnatifida), originating from the Pacific and now established in temperate regions worldwide“. This was recently explained in an interview with Piernext by Xavier Turon, a researcher from CEAB-CSIC.
According to the Report on the Assessment of Invasive Exotic Species and their Control, prepared by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), in which Turon himself participated, invasive exotic species are one of the five main drivers of biodiversity loss and play a significant role in 60% of global plant and animal extinctions. This is because some native species, having not evolved in contact with these newcomers, cannot compete with them; they are displaced and, in the worst cases, die and become extinct.
Beyond the ecological impact, these invasions also have economic consequences, affecting crops, fisheries, and more. It is estimated that they generate costs exceeding 400 billion dollars (data from 2019).
A difficult problem to solve
Addressing this issue is complicated given the context of globalization and global change. However, it can be limited by focusing on the causes that favor the spread of invasive exotic species.
Infrastructure can play a relevant role. For example, specifically regarding the Suez Canal, Xavier Turon explained to Piernext that “re-establishing saline barriers would be effective so that species encounter an impediment to their dispersion“. Ports can also cooperate by establishing inspection and monitoring programs (to prevent newly arrived species from spreading to nearby natural communities). They can exchange information with other ports, both locally and internationally, to warn of the presence of a dangerous species at a certain point. For vessels, it is about ensuring they comply with required regulations for ballast water management.
Knowing the characteristics and life cycles of invasive species is also key. The CEAB-CSIC researcher, in the same interview, mentioned that this knowledge has very important applications: “For example, placing juvenile mussels or oysters for farming a month earlier or later can prevent the settlement of some invasive species on the bivalves”.
And above all, early detection followed by rapid containment and mitigation measures is crucial to control the invasive species and limit its negative impacts as much as possible.
In this regard, the work done by various teams at CEAB-CSIC stands out. They collaborate with different entities (such as the Catalan Water Agency) in early detection, monitoring, and containment measures for invasive exotic species, both in marine and inland waters.
The Center also dedicates efforts to raising awareness and disseminating information on this issue. In addition to coordinating citizen science platforms like Observadores del Mar (which has already helped in the early detection of invasive species), we conduct outreach activities aimed at both directly involved sectors and the general public. For the latter, we are preparing an interactive exhibition scheduled to open this fall at the Maritime Museum of Barcelona.
