Solving Ariadne’s thread in the blue crab invasion to turn it to a true paradigm of circular economy: eco-biological traits and valorization of by-products to enhance fisheries value, a scoping review

The blue crab (*Callinectes sapidus*) has emerged as one of the most problematic invasive species in the world, particularly following its introduction to the Mediterranean in the mid-20th century. This situation presents a complex challenge, not unlike the mythological tale of Ariadne’s thread, where the solution lies in guiding us through a labyrinth of ecological and economic implications. Recent research, including insights from our prior work on the integrated ecological and biochemical approach to the management of the invasive blue crab Callinectes sapidus in a Po Delta lagoon, reinforces the necessity of redirecting our focus toward human consumption as a means of controlling this invasive species. This not only addresses the ecological threats posed by the blue crab but also opens new avenues for sustainable fisheries.

The scoping review highlights how the blue crab's ecological adaptability and high nutritional value can be leveraged for economic gain, transforming a liability into an asset. By valorizing by-products, such as shells traditionally considered waste, we can tap into high-value markets for bioactive compounds like chitin and chitosan. These compounds have applications across various industries, including food production and animal husbandry. However, the current underdevelopment of blue crab fisheries in Europe, largely due to consumer attitudes and restrictive regulations, underscores the disconnect between potential and practice. The review emphasizes the need for proactive strategies to change perceptions and regulations surrounding this species, thus turning the tide in favor of a circular economy.

Moreover, the implications of climate change cannot be overlooked. As the blue crab continues to establish itself in new regions, its adaptive traits suggest a potential for continued spread. This persistence indicates that instead of viewing blue crabs solely as an invasive threat, we should also consider how their exploitation could contribute to ecological balance. The circular valorization of blue crab by-products not only promotes sustainable fishing practices but also reinforces the importance of integrating ecological understanding with economic strategy. The urgency of addressing invasive species through innovative solutions is a critical aspect of marine stewardship that all stakeholders must embrace.

As we look ahead, the success of initiatives like these will depend on collaborative efforts among researchers, policymakers, and the fishing industry. Changing consumer attitudes toward the blue crab and supporting regulatory frameworks that facilitate its exploitation will be vital. The question remains: will we seize this opportunity to transform a challenge into an economic and ecological advantage? By leveraging the insights gained from ongoing research and focusing on circular economy principles, we can create a more resilient marine ecosystem while enhancing the value of our fisheries. The blue crab saga is a compelling reminder that with innovative thinking and collaborative effort, we can navigate the complexities of invasive species management and turn potential crises into opportunities for sustainable development.