We carried out this research in two southern European countries (Apulia region, southern Italy and precisely in Lesina lagoon as depicted in Figure 3 , and Algarve region, southern Portugal and exactly in Faro, Olhao, Moncharapaco, Fuseta, Castro marim, Vila Real de Santo António and Monte Gordo as shown in Figure 4 ) ¹ . We based our selection on several scientific and practical considerations, reflecting the relevance of the two locations for the study of the C. sapidus. Concretely, the importance of the two selected study areas could be highlighted by their designations as conservation areas and the active participation of local communities in research and biodiversity conservation.

On the one hand, Apulia region, particularly the Lesina lagoon, offers a unique and diversified environment for studying the impacts of the C. sapidus. This lagoon, located along the southern Adriatic coast, is recognized as an area where the blue crab has already proliferated (Cilenti et al., 2015; Renzi et al., 2020), and is a semi-closed system influenced by both fresh and marine waters. Furthermore, this lagoon ecosystem is heavily exploited by humans, with fishing and aquaculture activities serving as significant sources of income (Breber et al., 2010). Consequently, those activities represent important sources for the economy of local fishery, which could be influenced by the invasion of the C. sapidus (Manzo et al., 2016).

On the other hand, the Algarve region in Portugal, with particular emphasis on the area between Faro and Vila Real de Santo António, offers a diversified coastal context rich in estuarine habitats. The presence of the blue crab in this area, particularly in the Ria Formosa Lagoon and Guadiana estuary, has already raised concerns for the artisanal fishing industry and the local marine ecosystem. Moreover, the Algarve region has been internationally recognized for its biodiversity and ecological value, further emphasizing the importance of understanding the impacts of the blue crab invasion on this delicate ecosystem (Cartaxana et al., 2009; Morais et al., 2019; Vasconcelos et al., 2019).

For the purposes of this research, we used the SEICAT methodology that is a novel standardized system based on human well-being is proposed for categorizing alien taxa according to their socio-economic impacts (Bacher et al., 2018; Probert et al., 2023) as depicted in Table 1 . This approach aims to serve as a practical tool capable of: (i) assessing the magnitude of socio-economic impacts caused by alien taxa; (ii) facilitating cross-regional and cross-taxa comparisons; (iii) predicting potential future impacts of species in target regions and beyond; and (iv) assisting in prioritizing management actions for alien taxa and relevant introduction pathways. Particularly, we selected this approach due to its relevant characteristic of providing transparent and comparable impact measures grounded in clear and explicit definitions (Jeschke et al., 2014).

We gathered information through an interaction with the fishermen ² , from October 2023 to February 2024, engaging 66 valid fishermen, considering the small-scale and artisanal fishing activities in the study areas and, operating at different fishing sites bordering the Lesina lagoon in Apulia region, Ria Formosa lagoon and Guadiana Estuary in Algarve region. Additionally, we used the Equation 1 (Petrontino et al., 2024) considering a margin of error 10%, and a confidence level of 95%, in which we calculated a sample size of 53 respondents and then we decided to increase this value to 66, divided into equal sizes between the selected study areas. However, we conducted also a rapid appraisal survey, revealing that the number of fishermen engaged in small-scale artisanal fishing and having already at least one contact with the concerned aquatic invasive species was 33 and 36 in Apulia and Algarve regions, respectively.

Where: n is the least sample size of artisanal small-scale fishermen in the selected study areas, calculated initially at 53 fishermen. During the survey, we succeed to increase this sample size by interviewing an actual number of 66 fishermen. N is the population size in terms of artisanal small-scale fishermen in the selected study areas (N=119: the total population of artisanal fishermen in the surveyed areas in Apulia is 41, while in the Algarve, it is 78, according to the (European Fllet Register - European Commission, 2023). e: is the considered margin of error (percentage in decimal form: 10%). z: is the z-score (z = 1.96 for a desired confidence level of 95%), and p is the standard deviation (p = 0.5)

Accordingly, we designed a questionnaire ( Supplementary Material A ), to capture SEICAT data, into three different sections. The first section explored the technical characteristics of the fishing enterprise: this section gathered details about the fishing area, duration of professional fishing activity, primary fishing seasons, boat specifications (e.g., registration number, length, gross tonnage, engine power), main fishing gear used, and membership in fishing cooperatives. The second section of the questionnaire focused on collecting opinions and perceptions regarding the consequences of this bio-invasion. It included questions related to well-being implications such as income, expenses, damages to nets and catches, physical injuries, and changes in fishing activity. Specifically, it examined the remodulation of fishing activities in terms of the number of fishers, fishing areas, and the quantity of catch. The third section revealed the socio-economic characteristics of fishermen, including data such as: age, gender, place of residence, family composition, education level, occupations, and annual family income. We ensured that the true impacts based on SEICAT’s semi-quantitative scale could be effectively captured with relatively low uncertainty, provided that robust survey methods were adopted (Probert et al., 2023).

On the one hand, the socioeconomic data, including variables such as gender, age, seniority, income, family size, principal tools, and other occupations, were analyzed using descriptive statistics, including mean, standard deviation, and relative frequency with the IBM SPSS Statistics software version 29. On the other hand, we conducted an Exploratory Factor Analysis (EFA), identifying latent variables, understanding the impact of the blue crab on the well-being and activities of fishermen in the two study areas, and underlying the observed variables in the dataset. In addition, we carried out a Hierarchical Analysis and K-means Cluster Analysis, identifying clusters of respondents with similar characteristics. Before performing the EFA, we also carried out the Kaiser-Meyer-Olkin (KMO) test to verify the adequacy of the sample, determining if the data are suitable for factor analysis, with a p-value less than 0.05, indicating the rejection of the null hypothesis and to conclude that there are significant correlations between the variables. As such, the use of the KMO test and Bartlett’s test of sphericity is crucial in cluster analysis, particularly when EFA is a preliminary step. The objectives of the cluster analysis were to identify and compare the different typologies of fishermen to understand which groups perceived the effects of the blue crab invasion more pronouncedly or less pronouncedly and how various factors influence each other. This approach provided an in-depth overview of the various facets of blue crab impacts, as well as identified any significant differences in perceptions between the fishing communities in the two geographic areas under consideration. Consequently, we obtained a KMO value of 0.558 for Apulia study area, suggesting mediocre sampling adequacy, while for Algarve study area, the KMO value was 0.761, indicating a good suitability. In both cases, the p-value is<0.05, indicating that correlations among variables were sufficiently high for factor analysis. These results validate the data structure, ensuring that it is appropriate to proceed with clustering techniques like K-mean cluster analysis. Moreover, we assessed the normality and homoscedasticity of the data using the Shapiro-Wilk test, which showed no significant deviations from normality for the variables analyzed.

Table 2 provides a comprehensive overview of the socio-economic and operational characteristics of fishermen in the Apulia and Algarve areas, highlighting differences in seniority, fishing practices, boat specifications, cooperative involvement, education levels, secondary occupations, and income distribution. It reveals that the sample surveyed was evenly divided between the two areas under analysis: 50% conduct their fishing activities in the Lesina lagoon, while the remaining 50% operate in several municipalities within the Algarve region. Apulian’s fishermen had almost the same average seniority (42 years) compared to those in the Algarve (41 years). In Apulia, 42% of fishermen fished exclusively in autumn, whereas 58% fished year-round. In contrast, 97% of fishermen in the Algarve fished year-round. The average length of boats was nearly identical, measuring 8 meters in Apulia and 7 in the Algarve. However, boats in the Algarve had higher engine horsepower. In addition, in Apulia, there was greater participation in cooperatives, with 52% of fishermen involved, compared to only 15% in the Algarve. With respect to the socio-economic parameters, the age distribution showed 55% of fishermen were aged between 30-64 years, and 45% were over 65 years in Apulia. In the Algarve, the age distribution was more diverse: 3% were under 30 years, 70% were 30-64 years, and 27% were over 65 years. Moreover, all respondents in both regions were male, and the average household size was three members. In terms of education, 58% of Apulia fishermen had an elementary education, 39% had middle school education, and 3% had high school education. In the Algarve, 85% had middle school education and 15% had high school education. Regarding the occupation aspects, a higher percentage of fishermen in Apulia (36%) had secondary occupations (18% in agriculture and 18% in industry) compared to the Algarve (18%), where the secondary occupation was primarily in food service. In Algarve, 48% of respondents reported an annual income, from fisheries and secondary occupation, between EUR 20,000 and 40,000 and 52% an annual income less than EUR 20,000, while in Apulia, only 39% fall between EUR 20,000 and 40,000, and the remaining 61% hold an annual income less than EUR 20,000.

The studied areas exhibited markedly different perceptions of the impact of the blue crab invasion on the well-being of fishermen. On the one hand, in Apulia, the invasion had significantly impacted various aspects of fishing. All respondents confirmed damage to nets (DAMN), with 52% rating it as very significant ( Figure 5 ). Also, increased costs (COST, i.e., due to gear damage, increased fuel consumption, and the need for new equipment to handle blue crabs invasion) were noted by 94% of respondents, and 39% considered this increase as very significant. Moreover, physical damage (DAMP, i.e., fishermen’s injuries/physical harm, necessitating changes in handles practices and possibly protective equipment) caused by the crabs was reported by 82%, with 33% describing the impact as very significant. Additionally, 97% perceived a reduction in the presence of other commercial species (REDP), with 33% rating this as very significant. The increase in working hours (INCRL) was noted negatively by 94% of respondents, with 30% rating it as very significant. Lastly, 97% of fishers noted catch damages (DAMC, i.e., changes in fishing techniques in terms of extensive or severe damages to fishing nets, and increase in working hours to maintain the catch levels) with 24% rated as very significant, and 61% perceived a reduction in income (INC) as negative, with 9% considering it very significant. On the other hand, in Algarve, the impact on well-being had a slightly different negative effect. 67% of fishermen confirmed damage to fishing equipment (DAMN), with the majority, 39%, considering it significant. Increased cost (COST) was reported by 88% of respondents, with 48% considering it very significant. Physical damage (DAMP) was reported by 45%, with 30% rating it as significant. Additionally, only 20% perceived a reduction in other commercial species (REDP), with 21% considering it significant. Moreover, 91% perceived an increase in working hours (INCRL), with 58% rating it as very significant. Furthermore, 67% reported damage to the catch (DAMC), with the majority, 39%, considering it significant, and finally, 52% perceived a reduction in income (INC), with the majority, 39%, rating it as significant.

With respect to the impacts on the fishermen’s activity size, in Apulia, 64% of respondents claim that the invasion has led to abandonment in some fishing areas (ABAN), while 76% report a reduction ( Figure 6 ) in other areas (REDU1). Furthermore, 79% affirm a reshaping of fishing activities (RESH), while 45% state that some fishermen have also abandoned the activity (RNFI). Moreover, 61% report catching less fish following the invasion (FISH). In contrast, in Algarve, 24% of respondents indicate that the incursion has resulted in abandonment in certain fishing zones (ABAN), while 27% note a decrease in others (REDU1). Furthermore, 15% acknowledge a restructuring of fishing operations (RESH), with an additional 15% stating that some fishermen have also discontinued the activity (RNFI). Moreover, only the 30% perceived a negative impact on the amount of catch reporting to catch less fish (FISH). In Apulia, 40% of fishermen sell the crab while 60% discard it. In contrast, in Algarve, 97% of fishermen sell the crab and only 3% discard it. Summing-up, the Figure 7 , based on Table 1 , revealed that the C. sapidus had an overall average negative activity impact on fishing activities. According to SEICAT rules and guidelines, in Apulia, the overall activity impact was categorized as Moderate (MO) while in Algarve, it was considered as Minor (MN).

Based on the EFA analysis, two clustering processes have been performed, based on the criterion of minimizing within cluster variance: each fisherman was assigned to the cluster whose centroid is closest, using Euclidean distance as the measure of proximity. Consequently, in Apulia, four clusters of fishermen ( Figure 8 ) have been identified based on their responses to the impacts of the blue crab invasion. The cluster 1 (36% of respondents) and cluster 3 (52% of respondents) are named “Resilient Fishermen” as they both perceive a moderate overall impact. Specifically, cluster 1 is associated with a decline in other commercial species, while the cluster 3 reports physical harm and an increase in work. Cluster 2 (9% of respondents), named “Struggling Fishermen,” was the most affected by the invasion, although they did not declare significant impacts on physical harm or an increase in workload. Furthermore, the cluster 4 (3% of respondents), named “Catch-Concerned Fishermen,” perceives an overall low impact from the invasion, indicating that catch reduction was not relevant for their income, but reports a significant reduction in the amount of catch. In Algarve, four clusters of fishermen ( Figure 9 ) also have been identified based on their responses to the impacts of the blue crab invasion. Cluster 1 (36% of respondents), referred to as “Resilient Fishermen,” experienced a minor impact overall, particularly regarding increased costs, physical harm, and net damage. Cluster 2 (9% of respondents), described as “Moderately Impacted,” faced significant challenges related to increased work, reduced income, and decreased catch. The cluster 3 (52% of respondents), termed “Struggling Fishermen,” reported a highly significant impact, especially concerning the remodeling of fishing activities and areas. Lastly, cluster 4 (3% of respondents), known as “Not Impacted Fishermen,” represents a small group that does not perceive any negative effects. Both in Apulia and Algarve, the most resilient clusters, which were the least affected, had capitalized on new market outlets and valued new market opportunities through the sale of blue crabs. As such, their ability to withstand the initial impacts indicated potential economic adaptation and suggests a capacity for effective response to future challenges posed by the blue crab invasion.

The two study areas, Apulia and Algarve, exhibit markedly different perceptions of the impact of the blue crab invasion on the well-being of fishermen. In Apulia, the invasion has significantly affected all the aspects, including damage to nets, physical damage, reduction in the presence of other commercial species, reduction in catch quantity, consequently, increase in working hours, increased costs, and reduction in income. In particular, the most significant perceived impact is related to damage to fishing nets, reinforcing the hypothesis that this factor is one of the main damages caused by the invasion for fishing operators, as reported in the study conducted in the Marchica lagoon, Morocco (Oussellam et al., 2021). In contrast, in Algarve, the perceived damage to nets is lower, although the most significant perceived impact is represented by the physical damages as described above, increase in working hours increased costs and reduction in income. These findings highlight the broader importance of significant impacts perceived by fishermen in Apulia compared to those in Algarve, where the effects are more concentrated on specific economic and labor-related challenges. Overall, this invasion has significantly impacted fishing techniques in several ways: (i) damage to fishing gear (In Apulia, the invasion has led to extensive damage to fishing nets, while net damage is reported as less severe in Algarve); (ii) changes in working hours (i.e., both areas reported increased in working hours), (iii) altered catch composition (i.e., in Apulia, there has been a decline in other commercial species, likely due to the competition or predation by blue crabs), (iv) reduced catch quantities (i.e., particularly in Apulia, where fishermen reported reduced catch quantities of their traditional target species), (v) increased costs (i.e., both regions reported higher costs associated with fishing activities, likely due to gear repairs, increased fuel consumption from longer working hours, and potentially new equipment needs), (vi) physical harm (i.e., fishermen in both regions reported concerns about physical harm from handling the aggressive blue crabs, which may necessitate changes in handling practices or protective equipment), and (vii) potential shift in target species (i.e., the abundance of blue crabs could lead to targeting this species a new commercial opportunity, especially if markets develop for blue crabs products).

While some fishermen clusters in both regions reported significant impacts, others demonstrated greater resilience or even opportunities in terms of selling blue crabs due to this invasion. Additionally, these results indicate the hypothesis for differentiated approaches in managing and adapting to the consequences of the blue crab invasion to meet the specific needs of fishing communities in different regions. This hypothesis can be derived from the fact that different types of fishing are practiced in Algarve and Apulia. In Apulia, crab fishing is not selectively practiced (Cilenti et al., 2024), whereas in Algarve, there is already targeted crab fishing, such as for the Cancer pagurus known as brown crab (Leitão et al., 2023). Consequently, the blue crab invasion appears to be less significant for those who are already using appropriate gears and are less vulnerable to damage from its presence. In the Algarve, where the product is actively fished, sold, and consumed, albeit to a lesser extent (Minor, according to the SEICAT scale), there is a perceived negative impact on fishermen. Even though the impact is considered minor, it remains negative because not all fishermen are equipped with appropriate fishing gear, leading to damage to catches of other commercial species.

Unlike Algarve, where nearly all fishermen (99% of those interviewed) sell the crabs, in Apulia, only a minority recognize its commercial value, driven by consumer preferences, and consequently market value of this product This suggests that, unlike in Apulia, Algarve has a tradition of crab fishing, where the species is abundant, valued, and widely consumed, making it easier for fishermen to sell their catch. Despite the known organoleptic properties and the well-established and expanding market in areas where it is native (Nanda et al., 2021), economic value varies regionally. In the USA, the blue crab is a well-recognized marine resource of high economic interest (Zohar et al., 2008), and similarly in Asia (Rabaoui et al., 2021). However, along the Adriatic coasts, artisanal fisheries are currently struggling to find solutions to cope with established crab populations since some years, but also growing exponentially in the last two or three years. Unlike the Algarve region, in Apulia there is no established supply chain for this product yet, and it is not widely consumed due to the lack of a consumption tradition. Fishermen are not equipped with appropriate fishing gear, leading to a more significant perceived impact. In this sense, the reduction of its population through commercial exploitation for human consumption in Italy, as has already been developed in several countries such as Egypt (Abdel Razek et al., 2016), Greece (Kevrekidis et al., 2023), Turkey (Ayas and Özogul, 2011; Harlıoğlu et al., 2018), Tunisia (Ennouri et al., 2021), and the USA (Sharov et al., 2003), may constitute one of the best comprehensive management controls of this threat (Marchessaux et al., 2023). Most efforts to measure and compare these impacts typically adopt utilitarian approaches by assigning monetary values to their costs (Zavaleta, 2000; Reinhardt et al., 2003; Born et al., 2005). However, quantifying socio-economic impacts in monetary terms is often challenging and may overlook important dimensions of human well-being. Previous endeavors to standardize socio-economic impacts using non-monetary metrics (e.g., GISS: Nentwig et al., 2010; Harmonia+: D’hondt et al., 2015) have struggled due to diverse descriptions of impact scenarios, complicating comparisons across impact categories.

The findings of this study are consistent with the hypotheses concerning the negative impacts associated with the invasion of C. sapidus (Nehring, 2011; Mancinelli et al., 2017), in relation to all the factors considered, as suggested and by the SEICAT methodology of Bacher et al. (2018). Specifically, artisanal small-scale fishermen have been recognized as the key target group to understand the effect of invasive species, considering their background and first-hand experience with the issue (Johnson, 2011; Vidal et al., 2020). Comparing studies conducted in other countries such as France and Tunisia (Marchessaux et al., 2023), where artisanal fishermen have been engaged to estimate the impacts of blue crab invasion, our study also confirms similarities, especially the negative influence on fishing activities and the reduction of other commercial species in the catch and associated income. However, in Portugal, these latter two factors are perceived to a significantly lesser extent. Conversely, our study does not fully align with the observations from the study conducted by Cerri et al. (2020) in Croatia, Italy, and Montenegro, where only a minority of the interviewed fishermen perceived a negative effect on fishing and the environment. This discrepancy is likely related to the positive trend of the invasion over the past five years, which has influenced the intensity and significance of the impacts. Finally, our observations, based on the perceptions of fishermen, align with the assessments of indirect damage caused by C. sapidus in Italy where it is estimated that the invasion of C. sapidus has led to an income decrease of about 30%, which could translate to a total economic loss of approximately EUR 200.000,00 per year (Cannarozzi et al., 2023).

This study shows that the impacts measured, mainly from a socio-economic point of view – which is treated by the SEICAT protocol – while the ecological impacts on the environment have not been the object of the study, are still perceived as negative, allowing to hypothesize and confirm that limiting the population expansion of C. sapidus, or containing it where it is already established, requires urgent management actions (Rotter et al., 2020). The first preliminary action for enabling an effective mitigation plan is early detection and monitoring in non-invaded areas. Informative campaigns on non-indigenous species carried out within research projects have facilitated the collection of initial and subsequent records (Falautano et al., 2020). The solution to the problem and this control management measure must, however, adopt a holistic approach, as suggested by Castriota et al. (2022) for the Pacific blue crab Portunus segnis. This includes: (i) the dissemination of appropriate fishing equipment and practices, along with demonstrations of their use, in line with EU Regulation 1380/2013. For example, the adoption of wire traps (Özdemir et al., 2015; Glamuzina et al., 2021), (ii) the promotion of blue crab in the market as a high-value fishery resource, accompanied by awareness campaigns to encourage its consumption, which can help reduce pressure on the local ecosystem (Falautano et al., 2020), (iii) the establishment of supply chains to facilitate the sale of the product by fishermen, reducing waste through circular economy activities such as chitin and chitosan extraction for various applications, primarily in the pharmaceutical and food industries (Hamdi et al., 2018; Casadidio et al., 2019). Moreover, the category of fishermen is generally resistant to change and adaptation to new measures and innovations. Therefore, another important management measure should be to implement: (iv) informative campaigns, training, and awareness programs, and to increase (v) public and private management programs to regulate control measures at national and international levels (Mancinelli et al., 2017). Furthermore, possible solutions and mitigation strategies may include the: (i) use of acoustic traps to track the movements of blue crabs; (ii) managing of the gates in the Lagoons inlet channels, to limit the entry of blue crabs larvae and the exit of adults for spawning; (iii) fishing for blue crabs during the fishing ban period of other species, and, (iv) adopting alternative fishing gears with larger mesh sizes.

The public and firm-side implications of a study about the socioeconomic threat posed by the blue crab to fishermen are manifold and significant. With respect to public implications, this includes: (i) public awareness: the study will contribute to informing the public and relevant authorities about the negative socioeconomic impact of the blue crab on the fishing community and local economy; (ii) resource management policies: the study’s findings may influence the development of marine resource management policies and strategies to mitigate the harmful effects of the blue crab on the fishing sector (Maggio et al., 2022). In terms of firm-side implications, this includes: (i) economic sustainability of fishermen: the study will help fishermen to understand better the economic challenges they face due to the presence of the blue crab and may provide useful information to adapt their fishing practices (Berkes et al., 2007); (ii) identification of diversification opportunities: the research may suggest diversification opportunities for affected fishermen, such as the development of new fishing techniques or the promotion of alternative income sources (Kasperski and Holland, 2013). In this direction, fishermen may adopt various strategies to market the blue crabs effectively: (i) direct sales to consumers at local markets, roadside stands or through community-supported fisheries, helping them to obtain better process by cutting out middlemen; (ii) wholesale to restaurants and retailers (i.e., establish relationships with them, ensuring a steady demand and often allows for bulk sales); (iii) online sales (i.e., e-commerce, expanding their markets reach beyond local areas); value-added products (i.e., such blue crabs cakes, soups, sauces, diversifying their offer and increasing their income); (iv) sustainable practices by stressing their sustainable fishing practices, leading to attract environmentally conscious consumers); (v) participation in festivals and events seafood to promote their products and connect with potential customers. As a result, these potential marketing strategies would help fishermen to maximize their profit and ensure a sustainable supply of blue crabs. Overall, this provides an empirical basis for management measures and interventions to mitigate the socioeconomic impacts of the blue crab on the fishing community and local economy, thereby contributing to the well-being of both individuals and the marine ecosystem (Kleitou et al., 2021).

On the one hand, the long-term implications for fishing communities may include an economic impact in terms of: (i) reduced income (i.e., fishermen in both regions have reported lower incomes due to the decline in other commercial species and the increased costs associated with repairing damaged gear and longer working hours); (ii) increased costs (i.e., there are higher operational costs due to gear damage, increased fuel consumption, and the need for new equipment to handle blue crabs; (iii) market adaptation (i.e., some fishermen may need to adapt by targeting blue crabs as a new commercial species, which could require market development and consumer education efforts); (iv) changes in fishing practices as described above, and (v) social and psychological impact (i.e., stress and uncertainty, which the invasion has led to increased stress and uncertainty among fishing communities, impacting their overall well-being and quality of life). On the other hand, the long-term implications for the marine ecosystem may include; (i) biodiversity and species interactions (i.e., decline in native species: the presence of blue crabs has led to a decline in other commercial species, likely due to competition and predation; disruption of trophic relationships: the blue crabs, being omnivorous and aggressive, can alter the food web dynamics by preying on a variety of organisms and competing with native species for resources); (ii) habitat alteration (i.e., ecosystem changes: the aggressive nature and high fecundity of blue crabs can lead to significant changes in habitat structure and function, potentially affecting the ecological balance of the invaded areas) and, (iii) potential for further spread (i.e., rapid expansion, which the blue crab population is expanding rapidly along the southern coast of Portugal and into the Mediterranean Sea, indicating a potential for further ecological and economic impacts in new areas).

Interviewing fishermen presents significant challenges, as many are unwilling to participate in interviews, as verified also during this study. Additionally, the methodology relies on participants’ perceptions, which can vary and be influenced by the presence or absence of the blue crab at the time of the interviews, in which the Lesina population had been interviewed in an earlier phase of the blue crabs’ invasion time course (Cannarozzi et al., 2023). Although seasonal variations and the subjective nature of fishermen’s experiences also pose challenges an effective collaboration with stakeholders is crucial for understanding the impacts and consequences of biological invasions (Rayon-Viña et al., 2022). However, a detailed analysis of the extent of damage inflicted by this phenomenon on professional fishing activities remains an area requiring further exploration. Consequently, future research should test various proposed solutions and evaluate the adaptability of fishermen and the market. This includes exploring circular economy solutions and sustainable adaptation practices like alternative fishing methods (Jabeur et al., 2022). Additionally, further studies should analyze the effectiveness of adopted strategies to identify weaknesses and suggest improvements, considering the dynamic economic, social, and environmental differences. Research on the blue crab exploitation, such as the production of soft-shell blue crabs for enhancing the commercial value of the species and the reuse of by-products and circular economy practices, such as chitin exploitation, is recommended (Cilenti et al., 2024; Tamburini, 2024). Furthermore, studying the willingness and capacity of fishermen to adapt to changes, and how this adaptability can be enhanced, is critical. Resistance to change and innovation among fishermen can hinder progress. Evaluating the “willingness to change” and the rapidity of adaptation among fishermen, along with assessing social aspects across different regions, is essential for future research (Rahman et al., 2022). Consequently, future studies should focus on identifying and addressing these challenges, followed by testing the implementation and effectiveness of the adopted strategies. This can be achieved by developing long-term output and outcome indicators, in line with the recommendations of General Fisheries Commission for the Mediterranean - GFCM/42/2018/7 (FAO, 2018). This approach will help evaluate the practical implementation and effectiveness of the measures, ultimately promoting sustainable fishing practices in affected areas. Finally, the determination of the pressure of the invasion would allow figuring out the exact perception by the fishermen of the two studied areas. In this direction, and to the best of our knowledge, there is a lack of statistical data focusing on the estimates of the abundance of blue crabs, and of their density across the two areas that also would be needed to overcome this last limitation of the study.