Population dynamics, habitat use and trapping efficiency of the invasive crab Callinectes sapidus in a Mediterranean hypersaline coastal lagoon

351 Population dynamics, habitat use and trapping efficiency of the invasive crab Callinectes sapidus in a Mediterranean hypersaline coastal lagoon Antonio A. Herrero-Reyes1, Adrián Guerrero-Gómez1, Antonio Zamora-López1, Mar Torralva1, José M. Zamora-Marín1,2 , Francisco J. Oliva-Paterna1 1 Department of Zoology and Physical Anthropology, Faculty of Biology, University of Murcia, CEIR Campus Mare Nostrum (CMN), Murcia, Spain 2 Department of Applied Biology, Centro de Investigación e Innovación Agroalimentaria (CIAGRO-UMH), Miguel Hernández University of Elche, Elche, Spain Corresponding author: Antonio A. Herrero-Reyes (antonioandres.herrer[email protected]) Copyright: © Antonio A. Herrero-Reyes et al. This is an open access article distributed under terms of the Creative Commons Attribution License (Attribution 4.0 International – CC BY 4.0). Research Article Abstract The blue crab (Callinectes sapidus) has rapidly invaded several coastal lagoons along the Western Mediterranean. However, there are still no comprehensive assessments of its population biology, habitat use and trapping efficiency in critical habitats. A two-year study (November 2021 – September 2023) was conducted in a natural corridor zone placed between the hypersaline Mar Menor coastal lagoon and the Mediterranean Sea. Our main goal was to assess the population structure, habitat use and trapping efficiency (four types of traps) of the blue crab. The blue crab shows a population dynamic and structure that reflects its full settlement and reproductive movements across the study area. Most captures corresponded to adults and subadults, peaking in summer, and largest crabs were recorded in November. A significant relationship was found between crab size, habitat type (Cymodocea nodosa meadows, Caulerpa prolifera meadows and bare substrates) and trap effectiveness. Trapping efficiency varied with both habitat characteristics and crab size, showing a positive relationship of juveniles and adults with muddy substrates, while water depth had a negative influence on juveniles and subadults. However, results supported great plasticity at the microhabitat scale. Fyke nets were identified as the most effective trapping method. Trap type significantly affected the number of captures as a function of crab size and sex, with subadults and females being predominantly captured in fyke nets. These findings provide novel insights into the species’ population biology in invaded regions and cost-efficient control methods, enabling the design of priority management strategies in shallow waters to minimize impacts from crab invasions and to ensure ecological integrity. Key words: Callinectes sapidus, control, management, population, Spain, transitional waters Introduction Biological invasions are increasingly recognised as a driver of global environmental change, contributing to biodiversity loss and ecosystem alterations (Roy et al. 2023). Invasive non-native species disrupt native ecosystems (Pyšek et al. 2020), generate substantial economic costs (Zenni et al. 2021) and can even facilitate the spread of human diseases (Guang Li et al. 2019). This issue is further exacerbated in aquatic environments, which face multiple anthropogenic pressures (Borgwardt et al. 2019; Poikane et al. 2020). Moreover, the inherent challenges of detecting and monitoring aquatic invasions and their impacts further exacerbate the Academic editor: Paula Chainho Received: 31 January 2025 Accepted: 11 June 2025 Published: 7 October 2025 Citation: Herrero-Reyes AA, GuerreroGómez A, Zamora-López A, Torralva M, Zamora-Marín JM, Oliva-Paterna FJ (2025) Population dynamics, habitat use and trapping efficiency of the invasive crab Callinectes sapidus in a Mediterranean hypersaline coastal lagoon. In: Anastácio P, Ribeiro F, Chainho P (Eds) Invasions in Aquatic Systems. NeoBiota 102: 351–375. https://doi.org/10.3897/ neobiota.102.148388 NeoBiota 102: 351–375 (2025) DOI: 10.3897/neobiota.102.148388 Advancing research on alien species and biological invasions A peer-reviewed open-access journal NeoBiota 352 NeoBiota 102: 351–375 (2025), DOI: 10.3897/neobiota.102.148388 Antonio A. Herrero-Reyes et al.: Habitat use and trapping efficiency of blue crab in hypersaline coastal lagoon vulnerability of these ecosystems (Gallardo et al. 2015; Guareschi et al. 2021). In the Mediterranean basin, this problem is pronounced, with numerous invasive species establishing populations in marine, transitional, and freshwater habitats (Muñoz-Mas and García-Berthou 2020; Zamora-Marín et al. 2023a, 2023b). The successful establishment of invasive species, particularly within the order Decapoda, is often linked to their auto-ecology and life history traits, including high reproductive output, wide ecological tolerance, and aggressive behaviour (Brockerhoff and McLay 2011; Rato et al. 2021). Among decapods, the Atlantic blue crab Callinectes sapidus Rathbun, 1896, (henceforth, the blue crab), which is considered one of the 100 worst invasive species in the Mediterranean Sea (Streftaris and Zenetos 2006), has become a prominent invader across Mediterranean estuarine and coastal ecosystems (Mancinelli et al. 2021). Native to the Atlantic coast of the Americas, from Canada to Argentina (Millikin and Williams 1984; Nehring 2011; Scalici et al. 2022), this species thrives in diverse aquatic environments ranging from marine waters to estuaries and river deltas. The invasion process of blue crab along European waters, including the Mediterranean basin, the Black Sea, and parts of the Atlantic, highlights its capacity to adapt and expand rapidly in non-native regions (Aydin 2017; González-Ortegón et al. 2022; Castriota et al. 2024). The high ecological plasticity of the blue crab, its broad diet range, and low level of direct competition with native crustaceans have facilitated its rapid spread along the Spanish coast (González-Ortegón et al. 2022; Clavero et al. 2022). The complex life cycle of this species involves differential macrohabitat use, with estuaries and offshore waters acting as key nursery and reproductive grounds, respectively (Ogburn and Habegger 2015). This marked plasticity in habitat selection combines with a generalist feeding strategy that includes predation on both invertebrates and vertebrates, as well as detritus and carrion consumption (Mancinelli et al. 2016; Prado et al. 2022; Ortega-Jiménez et al. 2024; Vivas et al. 2025). Both traits have promoted a significant predation pressure on both commercially important and threatened species in the Spanish coast, such as the European eel Anguilla anguilla (Linnaeus, 1758) (Clavero et al. 2022). As a result of its significant ecological and economic impacts, the blue crab has recently been identified as one of the most problematic aquatic invasive species in the Iberian Peninsula (Oficialdegui et al. 2023). Despite the increasing number of records documenting the ongoing expansion of blue crab in the Mediterranean basin (Mancinelli et al. 2021; Gil-Fernández et al. 2024), there are still significant knowledge gaps on its demographic and ecological characteristics in recently invaded environments (Mancinelli et al. 2017b). So far, few studies provide quantitative data on the abundance and structure of established populations (e.g. Clavero et al. 2022; Marchessaux et al. 2023a, Mancinelli et al. 2024). Furthermore, field studies assessing effectiveness of different fishing methods and mesh size have been rarely conducted (Özdemir et al. 2015; Glamuzina et al. 2021). This lack of methodological assessments hampers efforts to effectively control blue crab populations and mitigate ecological and economic impacts associated with its invasion. In 2004 the blue crab was first documented in the Mar Menor coastal lagoon (Giménez-Casalduero et al. 2016), which is one of the largest hypersaline lagoons in the Mediterranean region. The Mar Menor supports a diverse fishery and provides critical habitats for both commercially valuable and conservation-priority species (Pérez-Ruzafa et al. 2020). Despite its legal protection under multiple international and national frameworks (e.g. Ramsar Convention and Natura 2000 network), the Mar Menor has continued to experience significant anthropogenic pressures. Recently, 353 NeoBiota 102: 351–375 (2025), DOI: 10.3897/neobiota.102.148388 Antonio A. Herrero-Reyes et al.: Habitat use and trapping efficiency of blue crab in hypersaline coastal lagoon it became the first European ecosystem to be recognized as a legal entity, granting its explicit rights (Gobierno de España 2022). However, these conservation efforts have not been sufficient to mitigate human-induced impacts, which have escalated in recent years, leading to severe ecological consequences (Álvarez-Rogel et al. 2020). In this context, the blue crab colonization and rapid expansion have exacerbated both ecological degradation and economic losses (Vivas et al. 2025). However, a comprehensive understanding of its population dynamics, habitat preferences, and the suitability of different control measures within this unique hypersaline lagoon remains lacking. This study aims to address these knowledge gaps by assessing key population traits and trapping effectiveness of the blue crab in hypersaline and ecologically sensitive habitats of the Mar Menor coastal lagoon. More specifically, our objectives were: (1) to evaluate spatiotemporal variation in crab abundance and population structure; (2) to determine habitat use and potential effects mediated by season, size and sex of individuals; and (3) to assess the effectiveness of four different trapping methods that could potentially be used for population control. Our findings provide critical insights for managing this invasive species and mitigating its impacts on native biota and local fisheries. Methods Study area The study was conducted in a natural inlet (named “Encañizadas”; Province of Murcia, southeastern Spain) that is a functional and unique natural connection between the Mar Menor coastal lagoon and the Mediterranean Sea. The Mar Menor is one of the largest (136.5 km2) and most iconic coastal lagoons within the Mediterranean basin (Pérez-Ruzafa et al. 2020). Its salinity and water temperature currently range around 41–45 g/l and 13–28 °C, respectively (Pérez-Ruzafa et al. 2019). The Encañizadas area is placed at the northern end of a 21-km long sand bar and is included within the Salinas y Arenales de San Pedro del Pinatar Natural Park. This area also gains protection under international agreements, such as the Convention on Wetlands of International (it is a Ramsar site), Special Protected Areas of Mediterranean Importance and Natura 2000 Network (Robledano et al. 2018). Thus, the Encañizadas area concentrates several estuarine habitats of conservation-concern and endangered species listed in European Directives and international normative (e.g. Sterna hirundo Linnaeus, 1758, Sternula albifrons (Pallas, 1764), Apricaphanius iberus (Valenciennes, 1846) and Anguilla anguilla (Linnaeus, 1758)). A traditional fishing system is still practised in the area, which has contributed to preserving the ecological uniqueness of the Encañizadas as well as enhancing its cultural and ethnographic value (Belando et al. 2014; Robledano et al. 2018). The study area comprises 181 hectares dominated by large flooding surfaces, which are crossed by small sand islets and a network of hypersaline shallow channels with pseudo-tidal influence (Robledano et al. 2018). We divided the study area into two different sampling sectors (Fig. 1). The Mar Menor sector (MM) was in the inland section and was strongly influenced by the littoral dynamics of the lagoon itself, whereas the Mediterranean sector (MED) was mostly influenced by the Mediterranean dynamics. Sampling locations in both sectors were carefully established to ensure a balanced representation of bottom types (i.e. habitat types) characterising shallow waters across the study area. We evenly distributed trapping sites across three different habitat types: (1) vegetated bottoms dominated by Cymodocea nodosa (Ucria) Ascherson, 1870 354 NeoBiota 102: 351–375 (2025), DOI: 10.3897/neobiota.102.148388 Antonio A. Herrero-Reyes et al.: Habitat use and trapping efficiency of blue crab in hypersaline coastal lagoon meadows, (2) vegetated bottoms dominated by Caulerpa prolifera (Forsskål) J.V.Lamouroux, 1809 meadows, and (3) sandy muddy bottoms dominated by areas without vegetation (bare bottoms) (Fig. 1). Bottom habitat classification was defined based on the cartographic information of the submerged biocenosis in the study area (Belando et al. 2014), which was revised and updated prior to the start of the sampling. Blue crab in the Mar Menor The blue crab was first recorded in the Mediterranean in the 1950s, but its occurrence along the Spanish Mediterranean coast is more recent, with the species being documented in the Mar Menor for the first time in 2004 (Giménez-Casalduero et al. 2016). Following its detection in the Ebro Delta in 2012 (Castejón and Guerao 2013), the blue crab rapidly spread across various transitional coastal ecosystems along the Spanish Mediterranean coast (González-Wangüemert and Pujol 2016; Clavero et al. 2022), eventually crossing the Strait of Gibraltar (González-Ortegón et al. 2022). In southeastern Spain, the blue crab has shown a remarkable adaptability, inhabiting a wide range of salinity levels, from nearly freshwater systems to hypersaline environments (Bedmar et al. 2024), such as the Mar Menor coastal lagoon. As mentioned above, the first recorded capture of the blue crab in the Mar Menor dates to 2004, when three specimens were collected in the Encañizadas site. However, the first evidence of a self-maintaining population in the lagoon dates from 2016 (Vivas et al. 2025), when fisheries data confirmed its establishment. Commercial landings increased up to 900 kg in 2018 (Guijarro-García et al. 2019). Given the absence of recorded individuals during the intervening years, it seems reasonable to suggest that the recent demographic explosion of the species in the Mar Menor may be attributed to multiple arrival events. Therefore, the blue crab has had a constant presence in the lagoon for over a decade, with its growing population potentially influenced by habitat changes linked to eutrophication (Guerrero-Gómez et al. 2024). Figure 1. Geographical location of the study area in the Mar Menor coastal lagoon (southeastern Spain). Sampling sectors are framed in dashed-line squares: Mar Menor (MM) and Mediterranean (MED). Distribution of habitat types (Caulerpa prolifera, Cymodocea nodosa and bare substrate) across shallow areas and variation of water depth levels (isobaths) is also depicted. Modified from Belando et al. (2014). 355 NeoBiota 102: 351–375 (2025), DOI: 10.3897/neobiota.102.148388 Antonio A. Herrero-Reyes et al.: Habitat use and trapping efficiency of blue crab in hypersaline coastal lagoon Data collection Sampling visits were conducted every two months from November 2021 to September 2023, thus totalling 12 sampling visits and encompassing two complete annual cycles of monitoring (sampling periods). Both sectors were sampled consecutively (Fig. 1) and traps were deployed for 24 hours on average. We evaluated the crab trapping effectiveness of 4 types of traps (Fig. 2): (1) collapsible cylindrical traps (CCT), consisting of a cylindrical net with two openings placed on rigid folding rings; (2) fyke nets (FN), cone-shaped traps assembled on rigid rings (Glamuzina et al. 2021), which incorporate a 200 cm cloth wall at the entrance to guide fishes into inside; (3) flat ‘bee-hive’ type traps (BHT), a cylindrical plastic-net container with a single entrance on the top; (4) minnow traps (MT), small cylindrical and rigid structures with two entrances at both sides (Harrison et al. 1986). At each habitat type, we deployed three units of each type of trap with the aim of assessing trapping effectiveness in each of the sectors. Accordingly, we deployed a total of 36 traps per sampling sector during each sampling visit: 3 traps x 4 trap types x 3 habitat types. Traps were always baited with fresh chicken to promote crab attraction and to allow for an increased trapping effectiveness. During trap retrieval, we recorded the number of blue crabs captured per trap and their sex based on their apron shape (Jivoff and Hines 1998). Carapace width (hereafter CW) was measured between the two most external lateral spines by using a vernier calliper (± 1 mm). Additionally, we also recorded species-level abundance and richness data of other non-target animal taxa unintentionally captured by traps. For each sampling event, water temperature (°C), conductivity (µS/cm), salinity (g/l), dissolved oxygen (mg/l), and oxygen saturation (%) were measured three times Figure 2. Illustration of the different trap types used for blue crab sampling across shallow waters of the Mar Menor coastal lagoon (SE Spain). A. Collapsible cylindrical trap (CCT); B. Minnow trap (MT); C. Flat ‘bee-hive’ type trap (BHT); D. Fyke net (FN). Length, height, mesh size and entrance diameter (Ø) of each trap type is indicated. Trap entrances are marked in red. 356 NeoBiota 102: 351–375 (2025), DOI: 10.3897/neobiota.102.148388 Antonio A. Herrero-Reyes et al.: Habitat use and trapping efficiency of blue crab in hypersaline coastal lagoon at each habitat type per sampling sector by using a multiparameter WTW® Multi340i or HACH® HQ30d. Submerged habitat variables were recorded at trap level. Using the trap position as the centre of a square of 10 m2 surface area, six variables related to microhabitat structure and presence of refuge for fauna were considered: submerged vegetation cover per m2 (%), water depth (cm), percentage of substrate size categories, according to Bain and Stevenson (1999): mud, sand, gravel, pebble and boulder. Submerged vegetation variables were visually assessed always by the same observers. Water depth was manually recorded by using a 1-cm marked portable stick. Data analysis The relative abundance of the blue crab was computed as capture per unit effort (hereafter CPUE), which was calculated as the number of individuals captured per trap per 24 hours. The maturity stage of crabs was classified in age classes (i.e. juveniles, subadults and adults) based on CW size, since this measurement has been successfully proven as a proxy of crab maturity (Fisher 1999). Following Ju et al. (2003), size-based age classes were established into three main categories: juveniles (CW < 80 mm), subadults (80 mm ≤ CW < 120 mm) and adults (CW ≥ 120 mm). A model calibration was performed to determine whether habitat (i.e. habitat type) and trapping effectiveness are both or separately linked with the size (i.e. size classes), or with the sex of the blue crabs. Furthermore, sex was modelled according to its potential relationship with sampling sector and trapping effectiveness. Four hypotheses were tested for every model to assess the influence of size or sex with these factors (Suppl. material 1: table S1). Log-Gaussian Generalized Additive Models (GAMs) were performed using the “mgvc” package (Wood 2011) for modelling effects from habitat and trapping effectiveness, using sampling period, month, type of trap, habitat type, dissolved oxygen, water temperature, salinity, water depth, mud cover and the cover of the meadow as predictive variables. For the sampling sector and trapping effectiveness, we considered as predictor variables the “sampling period” (e.g. 2021/22), “month”, “trap type”, “sampling sector” and “habitat type”. Hence, response variables were CPUE based on the age classes and sex. Model ranking and selection were based on the estimate of the standard correction to Akaike’s Information Criterion (AICc), to reduce biases caused by small sample size (Miller et al. 2023). When model comparisons yielded an inadequate support for the identification of the best model (AICc difference lower than 2), then the most parsimonious formulation (i.e. the model retaining less interactions) was selected (Cavanaugh and Neath 2019). Additionally, the deviance explained was calculated as a measure of model fitting. A stratified pairwise sampling (Tukey adjustment) from package “emmeans” (Lenth 2020) was also carried out to assess the relationship between the factors. All statistical analyses were conducted through the R free software (R Core Team 2023). Results Environmental variables Our environmental assessment reflected the hypersaline nature of the study area (Table 1), with an average salinity of 42.3 g/l in the sector with greater lagoon influence (MM), which was slightly higher than the recorded in the more 357 NeoBiota 102: 351–375 (2025), DOI: 10.3897/neobiota.102.148388 Antonio A. Herrero-Reyes et al.: Habitat use and trapping efficiency of blue crab in hypersaline coastal lagoon Mediterranean-influenced sector (MED). Water temperature remained homogeneous across both sectors, showing similar mean values and a temporal range between a minimum of 12.5 ± 0.1 °C (MM, January 2022) and a maximum of 35.2 °C ± 0.1 °C (MM, July 2022). The shallow nature and dominance of finegrained substrate of the study area are also reflected in habitat structure parameters, with mean depths not exceeding 64.3 ± 1.5 cm and substrates predominantly composed of muds and sands (Table 1). Abundance and population structure A total of 1981 specimens from 31 different taxa of macrofauna were caught over the study period (November 2021 – September 2023). From the total captures, 538 individuals corresponded to C. sapidus being the second dominant species behind the native shrimp Palaemon elegans (819 captures) (Suppl. material 1: table S2). Our results revealed the highest abundance of Callinectes sapidus during the warmer months in both sampling sectors (Suppl. material 1: table S4), with July and September totalling 25.6% and 39.3% of total catches (juveniles included), respectively. This temporal pattern was particularly pronounced in the MED sector, which exhibited a significantly lower number of captures as compared to the MM sector (75.9% of total captures in MM) (Figs 3, 4). Moreover, although the sex-ratio was dominated by males in most of the sampling events (Fig. 3), the MED sector recorded higher female catches within the study area, particularly in warmer months. However, this sector showed either negligible or no captures during the remaining sampling months (November, January, March, and May). Furthermore, ovigerous females (n = 4) were only captured in the MED sampling sector. Out of the total captures, 400 individuals were males and 135 were females, with 3 undetermined specimens, resulting in a sex ratio of 2.96:1 (males:females). However, markedly evident differences were observed between sampling sectors (Fig. 4), with sex ratios of 4.41:1 in MM and 1.15:1 in MED. The target population was dominated by subadults (49.8% of total catches) and adults (37.6%) specimens, whereas juveniles comprised a lower portion of the population (12.6%). Months Table 1. Summary table of the environmental characteristics and the microhabitat structure metrics. Data for the two sampling periods and the whole study period are presented in different columns, providing mean values ± standard error separately for the two sampling sectors: Mar Menor (MM) and Mediterranean (MED). Environmental variables Nov 2021 – Sept 2022 Nov2022 – Sept 2023 Nov 2021 – Sept 2023 MM MED MM MED MM MED Water temperature (°C) 21.2 ± 0.7 20.2 ± 1.1 21.6 ± 0.7 22.7 ± 0.6 21.4 ± 0.5 22.7 ± 0.5 Conductivity (µS/cm) 63.0 ± 0.2 51.2 ± 2.2 63.1 ± 0.2 57.5 ± 0.3 63.0 ± 0.1 57.6 ± 0.2 Salinity (g/l) 42.2 ± 0.2 34.1 ± 1.4 42.4 ± 0.3 38.2 ± 0.1 42.3 ± 0.1 38.3 ± 0.1 Dissolved oxygen (mg/l) 10.4 ± 0.5 10.4 ± 1.6 9.3 ± 0.3 9.2 ± 0.3 9.9 ± 0.3 10.4 ± 0.8 Oxygen saturation (%) 115.4 ± 5.6 102.2 ± 5.4 106.0 ± 4.0 104.8 ± 3.8 111.2 ± 3.6 109.6 ± 2.7 Water depth (cm) 44 ± 0 54.4 ± 1.7 43.6 ± 1.0 64.3 ± 1.5 42.3 ± 0.7 59.5 ± 1.2 Mud substrate (%) 37.9 ± 1.5 17.9 ± 1.0 26.9 ± 1.5 11.8 ± 0.7 32.3 ± 1.1 14.9 ± 0.7 Sand substrate (%) 59.0 ± 1.3 76.6 ± 1.7 68.8 ± 1.4 88.0 ± 0.7 64.0 ± 1.0 82.4 ± 1.0 Gravel substrate (%) 3.1 ± 0.4 0.7 ± 0.2 3.8 ± 0.4 0.1 ± 0.1 3.4 ± 0.3 0.4 ± 0.1 Pebble and boulder (%) 0.0 ± 0.0 0.0 ± 0.0 0.0 ± 0.0 0.0 ± 0.0 0.0 ± 0.0 0.0 ± 0.0 Submerged vegetation cover (%) (C. prolifera)95 ± 1.2 97.1 ± 0.7 97.3 ± 0.8 72.8 ± 3.0 96.1 ± 0.7 86.1 ± 1.8 Submerged vegetation cover (%) (C. nodosa)74.6 ± 3.1 78.7 ± 2.2 79.7 ± 2.3 99.2 ± 0.3 77.2 ± 1.9 89.6 ± 1.4 Submerged vegetation cover (%) (Bare) 2.6 ± 0.6 1.5 ± 0.4 1.1 ± 0.2 0.3 ± 0.2 1.9 ± 0.3 0.9 ± 0.2 358 NeoBiota 102: 351–375 (2025), DOI: 10.3897/neobiota.102.148388 Antonio A. Herrero-Reyes et al.: Habitat use and trapping efficiency of blue crab in hypersaline coastal lagoon Figure 4. Spatial differences between study sectors in CPUEs (A) and CW (B) values of blue crabs according to sex in the Mar Menor coastal lagoon. Values of captures per unit effort (CPUEs) and carapace width (CW) are shown as mean ± standard error. Both spatial approaches address the two study sectors separately: Mediterranean (MED) and Mar Menor (MM). Figure 3. Spatiotemporal variation in the number of captures of blue crabs in Encañizadas according to sex. Crab sampling was conducted throughout two complete sampling periods (2021/22 and 2022/23). Columns correspond to months whereby crab samplings were carried out, whereas rows represent captures for each sampling period in each of the two sampling sectors: Mar Menor (MM) and Mediterranean (MED). The dashed line distinguishes the three size classes (juveniles, subadults and adults). 359 NeoBiota 102: 351–375 (2025), DOI: 10.3897/neobiota.102.148388 Antonio A. Herrero-Reyes et al.: Habitat use and trapping efficiency of blue crab in hypersaline coastal lagoon with highest activity for C. sapidus (May to September) showed the greatest CW size range in the studied population, particularly in the MM sector. In the MED sector, only the sampling conducted at the end of the warm periods displayed a wide size range (Fig. 3; mean CW: 111.6 ± 2.6 mm), with a high abundance of adults and subadults. During the colder months, the size distribution was dominated by larger individuals, with the highest CW recorded in November in the MM sector (mean CW: 136.3 ± 2.7 mm). The largest individuals recorded corresponded to two males (CW: 171 mm; both captured in MED during September 2023), while the smallest individual was also a male (CW: 21 mm) recorded in MED during September 2023. The capture of different size classes was influenced by habitat type and trapping effectiveness, a pattern reflected from the dependence observed in the best fitted model (Suppl. material 1: table S3). Most of the blue crabs were caught in the MM sector, with only 130 individuals from the MED sector. In addition, there were no catches in the MED sector in five sampling months. Both results showed the strong influence of the study sector (lagoon or marine) on both crab presence and abundance. In fact, GAM model fitting analyses indicated that the best explanatory model for catches considers a significant relationship between the sampling sector and the sex of captured individuals (Suppl. material 1: table S3). The pairwise test showed that there were not significant differences in the abundance of males and females in the MED sector, while the abundance of males in MM sector was significantly higher than females. The test also demonstrated that blue crab females showed a significant preference for the MED sector, whereas males demonstrated a clear selection for the MM sector (Suppl. material 1: fig. S1). According to the coefficients of the best model (Suppl. material 1: table S3), major differences in sex-ratio were found between study sectors. Habitat use Based on the low number of captures obtained from the MED sector, analyses of habitat use and trapping effectiveness were conducted exclusively considering captures from the MM sector, which provides a reliable representation of the blue crab population in the study area. The habitat type was found to exert an influence on the catches of blue crabs (Fig. 5), particularly significant in the case of subadults and adults. The habitat type with the highest crab abundance was found to be bare substrate, showing this one as the most suitable for trapping the species. In contrast, vegetated habitat dominated by C. prolifera showed the lowest abundance (Fig. 5). The best fitted GAM model revealed that selection of habitat type by blue crabs relied on size (Figs 5, 6, Suppl. material 1: table S3). The influence of bare substrate was more significant for the subadult size class, but weaker for adults, which also showed a higher selection for vegetated habitats dominated by C. nodosa. Juveniles showed a significant preference for bare substrate, but just with respect to C. prolifera meadows (Suppl. material 1: fig. S2). In addition, the results showed a significant influence of the microhabitat structure on the abundance of the different size classes. According to the model smoothers (Fig. 6), an effect of prevailing substrate was found, with a significant effect of muds, mainly on juvenile and adult abundance. Water depth also showed a significant effect on size class abundance, with lower juvenile and subadult abundance in deeper waters, this relationship being particularly more marked for juveniles (Fig. 6). 366 NeoBiota 102: 351–375 (2025), DOI: 10.3897/neobiota.102.148388 Antonio A. Herrero-Reyes et al.: Habitat use and trapping efficiency of blue crab in hypersaline coastal lagoon structure of FN likely contributed to a higher biomass of captures and a broader size range, as already reported by Atar et al. (2002) for hoop nets (structurally similar to FN). Our ‘bee-hive’ type traps (BHT) were ineffective. Despite the excellent swimming ability of blue crabs (Houlihan et al. 1985), the top-entry design of BHT may further reduce their effectiveness in shallow waters. Minnow traps (MT) exclusively captured small juveniles (maximum CW of 64 mm), accounting for 23.5% of the total juvenile captures. This likely reflects the low abundance of juveniles rather than trap performance. Furthermore, MT prevents predation from larger conspecifics once small-sized crabs are inside the trap, making this trap type suitable for prolonged sampling events aimed to identify recruitment areas. Although cannibalism in blue crabs has been demonstrated (Hines 2007; Bromilow and Lipcius 2017), no evidence of this was observed inside the traps during our study (e.g. carcasses or remains). Juveniles could display avoidance behaviour towards traps containing adult crabs (Moir and Weissburg 2009), which would also explain their low capture rate. The mesh size and cloth wall of FN may reduce juvenile evasion by predators, while their preference for live prey over carrion (Seitz et al. 2011) could also influence the success of capture. No significant differences were observed between FN and CCT in capturing juveniles or adults. However, FN were slightly more effective for subadult crabs (Suppl. material 1: fig. S3) and in capturing females (Suppl. material 1: fig. S4), likely due to the cloth wall facilitating the entry of mobile individuals, particularly during spawning migrations. This is supported by the fact that 57.2% of adult females were captured using FN. Management recommendations In the Mediterranean Sea and associated coastal lagoons, such as the Mar Menor, the blue crab is a highly impactful invasive species with well-documented negative effects on local ecosystems (Mancinelli et al. 2017b; Clavero et al. 2022) and socio-economic activities (Glamuzina et al. 2021). Previous studies have highlighted the urgent need to implement effective management measures aimed to mitigate these impacts. Promoting commercial exploitation of blue crab populations offers a promising approach to control their abundance while offsetting economic losses in invaded areas (Marchessaux et al. 2023c; Mancinelli et al. 2024). However, commercial exploitation should be complemented with targeted management actions aimed to control blue crab populations in ecologically sensitive habitats (Mancinelli et al. 2017a). Minimizing ecological and economic impacts should be a primary goal of post-invasion management strategies. These strategies must be tailored to the species’ life history and the environmental conditions of the invaded ecosystem, targeting specific size classes and sexes. For example, identifying spawning corridors is crucial for an effective control, as targeting trapping efforts into these areas could significantly reduce the reproductive output of invasive populations. Our study underscores the complex interplay of ecological, physiological, and behavioural factors driving habitat selection in the blue crab. Sound management implications can be drawn from our results to optimize trapping protocols in shallow spawning corridors. A higher fishing pressure should be applied during warmer months when crab activity peaks, and traps should be deployed in predominantly unvegetated, muddy substrates or mixed habitats with patches of C. nodosa. FN and CCT were the most effective traps, with FN performing better for capturing a wider range of 367 NeoBiota 102: 351–375 (2025), DOI: 10.3897/neobiota.102.148388 Antonio A. Herrero-Reyes et al.: Habitat use and trapping efficiency of blue crab in hypersaline coastal lagoon size classes and being particularly effective for the capture of females. Future studies should explore alternative trap materials, mesh sizes, and entrance designs to enhance trapping effectiveness and to boost control strategies. Our results provide baseline information on blue crab population dynamics, habitat use and trapping efficiency in high salinity waters, which can inform monitoring and management in other invaded regions. By improving trapping protocols and integrating ecological knowledge, control strategies can be tailored to efficiently manage blue crab populations while minimizing impacts on native biodiversity and local fisheries. Acknowledgements The authors are grateful to other members of the Department of Zoology and Physical Anthropology of the University of Murcia for their help in field sampling and laboratory processing, particularly to Antonio Guillén Beltrán and Patricio López Martínez de la Plaza. We would like to thank the Aquatic Environment Section of the Scientific and Technical Research Area of the University of Murcia (SEMA) for the logistical support provided in this project and Salinas y Arenales de San Pedro del Pinatar Regional Park for facilitating access to the study area. We also thank the anonymous reviewer, as well as Giorgio Mancinelli and the editorial team, for their helpful comments that improved the original version of this manuscript. Additional information Conflict of interest The authors have declared that no competing interests exist. Ethical statement No ethical statement was reported. Use of AI No use of AI was reported. Funding Part of this research was supported by the Environmental Service and Mar Menor Service of the Government of the Autonomous Community of Murcia (CARM, Spain) and the contracts “Estudio, valoración y seguimiento de la ictiofauna y análisis de relaciones con otros grupos faunísticos. Estudio, valoración y seguimiento de la especie de cangrejo exótica invasora, Callinectes sapidus, de áreas someras e intermareales del Mar Menor” and “Estudio y seguimiento espaciotemporal de poblaciones faunísticas de gestión prioritaria (ictiofauna y la especie invasora Callinectes sapidus): Situación actual en zonas someras e intermareales del Mar Menor”. This study was also partially supported by the LIFE INVASAQUA project (Aquatic Invasive Alien Species of Freshwater and Estuarine Systems: Awareness and Prevention in the Iberian Peninsula) (LIFE17 GIE/ES/000515) funded by the EU LIFE Program. A.A. H-R. is supported by a predoctoral grant funded by University of Murcia (R-483/2023). J.M. Z-M. is supported by a postdoctoral grant funded by the Generalitat Valenciana and the European Social Fund Plus (CIAPOS/2023/129). Author contributions Antonio A. Herrero-Reyes: Writing – original draft, review & editing, Investigation, Methodology, Formal analysis, Data curation. Adrián Guerrero-Gómez: Methodology, Formal analysis, Investigation, Writing – review & editing. Antonio Zamora-López: Methodology, Formal analysis, 368 NeoBiota 102: 351–375 (2025), DOI: 10.3897/neobiota.102.148388 Antonio A. Herrero-Reyes et al.: Habitat use and trapping efficiency of blue crab in hypersaline coastal lagoon Investigation, Writing – review & editing. Mar Torralva: Investigation, Writing – review & editing, Funding acquisition, Project administration. José Manuel Zamora-Marín: Investigation, Supervision, Writing – original draft, Writing – review & editing. Francisco José Oliva-Paterna: Investigation, Funding acquisition, Supervision, Writing – review & editing, Validation. All authors have reviewed and contributed to improve the text and figures. Author ORCIDs Antonio A. Herrero-Reyes https://orcid.org/0000-0001-7358-9205 Adrián Guerrero-Gómez https://orcid.org/0000-0002-0790-1667 Antonio Zamora-López https://orcid.org/0000-0002-4337-1018 Mar Torralva https://orcid.org/0000-0003-1517-3337 José M. Zamora-Marín https://orcid.org/0000-0002-7021-267X Francisco J. Oliva-Paterna https://orcid.org/0000-0001-8288-5321 Data availability All of the data that support the findings of this study are available in the main text or Supplementary Information. References Aguilar R, Hines AH, Wolcott TG, Wolcott DL, Kramer MA, Lipcius RN (2005) The timing and route of movement and migration of post-copulatory female blue crabs, Callinectes sapidus Rathbun, from the upper Chesapeake Bay. Journal of Experimental Marine Biology and Ecology 319: 117–128. https://doi.org/10.1016/j.jembe.2004.08.030 Álvarez-Rogel J, Barberá GG, Maxwell B, Guerrero-Brotons M, Díaz-García C, Martínez-Sánchez JJ, Sallent A, Martínez-Ródenas J, González-Alcaraz MN, Jiménez-Cárceles FJ, Tercero C, Gómez R (2020) The case of Mar Menor eutrophication: State of the art and description of tested Nature-Based Solutions. Ecological Engineering 158: 106086. https://doi.org/10.1016/j.ecoleng.2020.106086 Aronhime BR, Brown KM (2009) The roles of profit and claw strength in determining mussel size selection by crabs. Journal of Experimental Marine Biology and Ecology 379: 28–33. https://doi. org/10.1016/j.jembe.2009.08.012 Atar HH, Ölmez M, Bekcan S, Seçer S (2002) Comparison of three different traps for catching blue crab (Callinectes sapidus Rathbun 1896) in Beymelek Lagoon. Turkish Journal of Veterinary and Animal Sciences 26(5): 1145–1150. https://journals.tubitak.gov.tr/veterinary/vol26/iss5/26 Aydin M (2017) First record of Blue Crab Callinectes sapidus (Rathbun 1896) from the Middle Black Sea Coast. Turkish Journal of Maritime and Marine Sciences 3: 121–124. Bain MB, Stevenson NJ (1999) Aquatic Habitat Assessment. American Fisheries Society 224. Bedmar S, Oficialdegui FJ, Clavero M (2024) Far‐reaching blues: Long‐distance migration of the invasive Atlantic blue crab. Aquatic Conservation 34(4): e4136. https://doi.org/10.1002/aqc.4136 Belando MD, Ruiz JM, García‐Muñoz R, Ramos‐Segura A, García P (2014) Cartografía de la vegetación sumergida del enclave natural de las Encañizadas del Mar Menor. Instituto Español de Oceanografía (Centro Oceanográfico de Murcia) y Asociación de Naturalistas del Sureste, 1-17. Bembe S, Liang D, Chung JS (2017) Optimal temperature and photoperiod for the spawning of blue crab, Callinectes sapidus, in captivity. Aquaculture Research 48: 5498–5505. https://doi. org/10.1111/are.13366 Borgwardt F, Robinson L, Trauner D, Teixeira H, Nogueira AJA, Lillebø AI, Piet G, Kuemmerlen M, O’Higgins T, McDonald H, Arevalo-Torres J, Barbosa AL, Iglesias-Campos A, Hein T, Culhane F (2019) Exploring variability in environmental impact risk from human activities across aquatic 369 NeoBiota 102: 351–375 (2025), DOI: 10.3897/neobiota.102.148388 Antonio A. Herrero-Reyes et al.: Habitat use and trapping efficiency of blue crab in hypersaline coastal lagoon ecosystems. The Science of the Total Environment 652: 1396–1408. https://doi.org/10.1016/j. scitotenv.2018.10.339 Brockerhoff A, McLay C (2011) Human-Mediated Spread of Alien Crabs. In: Galil B, Clark P, Carlton J (Eds) In the wrong place - alien marine crustaceans: distribution, biology and impacts. Invading Nature - Springer Series in Invasion Ecology, Dordrecht, 27–106. https://doi. org/10.1007/978-94-007-0591-3 Bromilow AM, Lipcius RN (2017) Mechanisms governing ontogenetic habitat shifts: Role of tradeoffs, predation, and cannibalism for the blue crab. Marine Ecology Progress Series 584: 145–159. https://doi.org/10.3354/meps12405 Carr SD, Tankersley RA, Hench JL, Forward RB, Luettich RA (2004) Movement patterns and trajectories of ovigerous blue crabs Callinectes sapidus during the spawning migration. Estuarine, Coastal and Shelf Science 60: 567–579. https://doi.org/10.1016/j.ecss.2004.02.012 Castejón D, Guerao G (2013) A new record of the American blue crab, Callinectes sapidus Rathbun, 1896 (Decapoda: Brachyura: Portunidae), from the Mediterranean coast of the Iberian Peninsula. BioInvasions Records 2: 141–143. https://doi.org/10.3391/bir.2013.2.2.08 Castriota L, Falautano M, Perzia P (2024) When nature requires a resource to be used—The case of Callinectes sapidus: Distribution, aggregation patterns, and spatial structure in northwest Europe, the Mediterranean Sea, and adjacent waters. Biology 13: 1–26. https://doi.org/10.3390/biology13040279 Cavanaugh JE, Neath AA (2019) The Akaike information criterion: Background, derivation, properties, application, interpretation, and refinements. Wiley Interdisciplinary Reviews: Computational Statistics 11: 1–11. https://doi.org/10.1002/wics.1460 Clavero M, Franch N, Bernardo-Madrid R, López V, Abelló P, Queral JM, Mancinelli G (2022) Severe, rapid and widespread impacts of an Atlantic blue crab invasion. Marine Pollution Bulletin 176: 113479. https://doi.org/10.1016/j.marpolbul.2022.113479 Davis AR, Benkendorff K, Ward DW (2005) Responses of common SE Australian herbivores to three suspected invasive Caulerpa spp. Marine Biology 146: 859–868. https://doi.org/10.1007/ s00227-004-1499-z Dittel AI, Epifanio CE, Fogel ML (2006) Trophic relationships of juvenile blue crabs (Callinectes sapidus) in estuarine habitats. Hydrobiologia 568: 379–390. https://doi.org/10.1007/s10750006-0204-2 Eggleston DB, Bell GW, Amavisca AD (2005) Interactive effects of episodic hypoxia and cannibalism on juvenile blue crab mortality. Journal of Experimental Marine Biology and Ecology 325(1): 18–26. https://doi.org/10.1016/j.jembe.2005.04.023 Fisher MR (1999) Effect of Temperature and Salinity on Size at Maturity of Female Blue Crabs. Transactions of the American Fisheries Society 128: 499–506. https://doi.org/10.1577/1548-86 59(1999)128%3C0499:EOTASO%3E2.0.CO;2 Florido R, Sánchez AJ (2010) Effect of seagrass complexity, prey mobility, and prey density on predation by the blue crab, Callinectes sapidus (Decapoda, Brachyura). Crustaceana 83: 1069–1089. https://doi.org/10.1163/001121610X521217 Gallardo B, Clavero M, Sánchez MI, Vilà M (2015) Global ecological impacts of invasive species in aquatic ecosystems. Global Change Biology 22: 151–163. https://doi.org/10.1111/gcb.13004 Gil-Fernández A, Rodilla M, Prado P, Falco S (2024) Early life stages of the invasive Atlantic blue crab Callinectes sapidus in the Western Mediterranean Sea. Estuarine, Coastal and Shelf Science 296: 108593. https://doi.org/10.1016/j.ecss.2023.108593 Giménez-Casalduero F, Ramos Esplá AA, Izquierdo Muñoz A (2016) Invertebrados marinos alóctonos en el Mar Menor. In: León VM, Bellido JM (Eds) Mar Menor: una laguna singular y sensible: evaluación científica de su estado. Instituto Español de Oceanografía, Ministerio de Economía y Competitividad, Madrid 6: 157–178. 370 NeoBiota 102: 351–375 (2025), DOI: 10.3897/neobiota.102.148388 Antonio A. Herrero-Reyes et al.: Habitat use and trapping efficiency of blue crab in hypersaline coastal lagoon Glamuzina L, Conides A, Mancinelli G, Glamuzina B (2021) A comparison of traditional and locally novel fishing gear for the exploitation of the invasive atlantic blue crab in the eastern adriatic sea. Journal of Marine Science and Engineering 9(9): 1019. https://doi.org/10.3390/jmse9091019 Gobierno de España (2022) Ley 19/2022, de 30 de septiembre, para el reconocimiento de personalidad jurídica a la laguna del Mar Menor y su Cuenca. BOE 237. González-Ortegón E, Berger S, Encarnação J, Chairi H, Morais P, Teodósio MA, Oliva-Paterna FJ, Schubart CD, Cuesta JA (2022) Free pass through the pillars of hercules? Genetic and historical insights into the recent expansion of the Atlantic Blue Crab Callinectes sapidus to the West and the East of the Strait of Gibraltar. Frontiers in Marine Science 9: 918026. https://doi.org/10.3389/ fmars.2022.918026 González-Wangüemert M, Pujol JA (2016) First record of the atlantic blue crab Callinectes sapidus (Crustacea: Brachyura: Portunidae) in the Segura river mouth (Spain, southwestern Mediterranean Sea). Turkish Journal of Zoology 40: 615–619. https://doi.org/10.3906/zoo-1511-23 Guang Li Z, Tang YY, Limpanont Y, Wu ZD, Li J, Lv ZY (2019) Zoonotic parasites carried by invasive alien species in China. Infectious Diseases of Poverty 8: 1–17. https://doi.org/10.1186/ s40249-018-0512-6 Guareschi S, Laini A, England J, Barrett J, Wood PJ (2021) Multiple co-occurrent alien invaders constrain aquatic biodiversity in rivers. Ecological Applications 31: 1–8. https://doi.org/10.1002/eap.2385 Guerrero-Gómez A, Zamora-López A, Torralva M, Zamora-Marín JM, Guillén-Beltrán A, Oliva-Paterna FJ (2024) Population dynamics of resident fish in a coastal lagoon under eutrophication-mediated habitat changes. Mediterranean Marine Science 25: 621–640. https://doi.org/10.12681/ mms.38054 Guijarro-García E, Vivas M, García E, Barcala E, Trives M, Muñoz A (2019) Atlantic blue crab (Callinectes sapidus Rathbun, 1896) in a protected coastal lagoon in SE Spain. In XX Iberian Symposium on Marine Biology Studies (SIEBM XX). Frontiers in Marine Science. https://doi. org/10.3389/conf.fmars.2019.08.00196 Harrison TD, Ramm AEL, Cerff EC (1986) A low-cost effective trap for use in sampling aquatic fauna. Aquaculture 58: 145–149. Hines AH (2007) Ecology of juvenile and adult blue crabs. In: Kennedy VS, Cronin LE (Eds) The Blue Crab: Callinectes Sapidus, 565–654. Hines AH, Lipcius R, Haddon A (1987) Population dynamics and habitat partitioning by size, sex, and molt stage of blue crabs Callinectes sapidus in a sub-estuary of central Chesapeake Bay. Marine Ecology Progress Series 36: 55–64. https://doi.org/10.3354/meps036055 Houlihan DF, Govind CK, El Haj A (1985) Energetics of swimming in Callinectes sapidus and walking in Homarus americanus. Comparative Biochemistry and Physiology 82: 267–279. https://doi. org/10.1016/0300-9629(85)90853-9 Hyman A, Chiu G, Seebo MS, Smith A, Saluta G, Lipcius R (2024) Ontogenetic Patterns in Juvenile Blue Crab density: Effects of Habitat and Turbidity in a Chesapeake Bay Tributary. Marine Ecology Progress Series 729: 135–150. https://doi.org/10.3354/meps14490 Jivoff P, Hines AH (1998) Female behaviour, sexual competition and mate guarding in the blue crab, Callinectes sapidus. Animal Behaviour 55: 589–603. https://doi.org/10.1006/anbe.1997.0646 Johnson DS (2022) Beautiful swimmers attack at low tide. Ecology 103(10): e3787. https://doi. org/10.1002/ecy.3787 Ju SJ, Secor DH, Harvey HR (2003) Demographic assessment of the blue crab (Callinectes sapidus) in Chesapeake Bay using extractable lipofuscins as age markers. Fish Bulletin 101: 312–320. Kampouris TE, Porter JS, Sanderson WG (2019) Callinectes sapidus Rathbun, 1896 (Brachyura: Portunidae): An assessment on its diet and foraging behaviour, Thermaikos Gulf, NW Aegean Sea, Greece: Evidence for ecological and economic impacts. Crustacean Research 48: 23–37. https:// doi.org/10.18353/crustacea.48.0_23 371 NeoBiota 102: 351–375 (2025), DOI: 10.3897/neobiota.102.148388 Antonio A. Herrero-Reyes et al.: Habitat use and trapping efficiency of blue crab in hypersaline coastal lagoon Kevrekidis K, Kevrekidis T, Mogias A, Boubonari T, Kantaridou F, Kaisari N, Malea P, Dounas C, Thessalou-Legaki M (2023) Fisheries Biology and Basic Life-Cycle Characteristics of the Invasive Blue Crab Callinectes sapidus Rathbun in the Estuarine Area of the Evros River (Northeast Aegean Sea, Eastern Mediterranean). Journal of Marine Science and Engineering 11(3): 462. https://doi. org/10.3390/jmse11030462 Lenth R (2020) Emmeans: Estimated Marginal Means, aka Least-Squares Means. R package version 1.4.5. Mancinelli G, Glamuzina B, Petric M, Carrozzo L, Glamuzina L, Zotti M, Raho D, Vizzini S (2016) The trophic position of the Atlantic blue crab Callinectes sapidus Rathbun 1896 in the food web of Parila Lagoon (South Eastern Adriatic, Croatia): A first assessment using stable isotopes. Mediterranean Marine Science 17: 634–643. https://doi.org/10.12681/mms.1724 Mancinelli G, Chainho P, Cilenti L, Falco S, Kapiris K, Katselis G, Ribeiro F (2017a) On the Atlantic blue crab (Callinectes sapidus Rathbun 1896) in southern European coastal waters: Time to turn a threat into a resource? Fisheries Research 194: 1–8. https://doi.org/10.1016/j.fishres.2017.05.002 Mancinelli G, Chainho P, Cilenti L, Falco S, Kapiris K, Katselis G, Ribeiro F (2017b) The Atlantic blue crab Callinectes sapidus in southern European coastal waters: Distribution, impact and prospective invasion management strategies. Marine Pollution Bulletin 119: 5–11. https://doi. org/10.1016/j.marpolbul.2017.02.050 Mancinelli G, Bardelli R, Zenetos A (2021) A global occurrence database of the Atlantic blue crab Callinectes sapidus. Scientific Data 8: 1–10. https://doi.org/10.1038/s41597-021-00888-w Mancinelli G, Lago N, Scirocco T, Lillo OA, De Giorgi R, Doria L, Mancini E, Mancini F, Potenza L, Cilenti L (2024) Abundance, size structure, and growth of the invasive blue crab Callinectes sapidus in the Lesina Lagoon, Southern Adriatic Sea. Biology 13: 1051. https://doi.org/10.3390/ biology13121051 Marchessaux G, Gjoni V, Sarà G (2023a) Environmental drivers of size-based population structure, sexual maturity and fecundity: A study of the invasive blue crab Callinectes sapidus (Rathbun, 1896) in the Mediterranean Sea. PLoS ONE 18: 1–23. https://doi.org/10.1371/journal. pone.0289611 Marchessaux G, Chevalier C, Mangano MC, Sarà G (2023b) Larval connectivity of the invasive blue crabs Callinectes sapidus and Portunus segnis in the Mediterranean Sea: A step toward improved cross border management. Marine Pollution Bulletin 194: 115272. https://doi.org/10.1016/j. marpolbul.2023.115272 Marchessaux G, Mangano MC, Bizzarri S, M’Rabet C, Principato E, Lago N, Veyssiere D, Garrido M, Scyphers SB, Sarà G (2023c) Invasive blue crabs and small-scale fisheries in the Mediterranean sea: Local ecological knowledge, impacts and future management. Marine Policy 148: 105461. https://doi.org/10.1016/j.marpol.2022.105461 Miller CR, Hyman AC, Shi DH, Lipcius RN (2023) Assessment of treatment-specific tethering survival bias for the juvenile blue crab Callinectes sapidus in a simulated salt marsh. PLoS ONE 18(10): e0289398. https://doi.org/10.1371/journal.pone.0289398 Millikin MR, Williams AB (1984) Synopsis of biological data on blue crab, Callinectes sapidus Rathbun. FAO Fisheries Synopsis, 38. Moir F, Weissburg MJ (2009) Cautious cannibals: Behavioral responses of juvenile and adult blue crabs to the odor of injured conspecifics. Journal of Experimental Marine Biology and Ecology 369: 87–92. https://doi.org/10.1016/j.jembe.2008.10.026 Muñoz-Mas R, García-Berthou E (2020) Alien animal introductions in Iberian inland waters: An update and analysis. The Science of the Total Environment 703: 1–10. https://doi.org/10.1016/j. scitotenv.2019.134505 Nehring S (2011) Invasion History and Success of the American Blue Crab Callinectes sapidus in European and Adjacent Waters. In: Galil BS, Clark PF, Carlton JT (Eds) In the Wrong Place - 372 NeoBiota 102: 351–375 (2025), DOI: 10.3897/neobiota.102.148388 Antonio A. Herrero-Reyes et al.: Habitat use and trapping efficiency of blue crab in hypersaline coastal lagoon Alien Marine Crustaceans: Distribution, Biology and Impacts. Springer Netherlands, 607–624. https://doi.org/10.1007/978-94-007-0591-3_21 Oficialdegui FJ, Zamora-Marín JM, Guareschi S, Anastácio PM, García-Murillo P, Ribeiro F, Miranda R, Cobo F, Gallardo B, García-Berthou E, Boix D, Arias A, Cuesta JA, Medina L, Almeida D, Banha F, Barca S, Biurrun I, Cabezas MP, Calero S, Campos JA, Capdevila-Argüelles L, Capinha C, Casals F, Clavero M, Encarnaçao J, Fernández-Delgado C, Franco J, Guillén A, Hermoso V, Machordom A, Martelo J, Mellado-Díaz A, Morcillo F, Oscoz J, Perdices A, Pou-Rovira Q, Rodríguez-Merino A, Ros M, Ruiz-Navarro A, Sánchez MI, Sánchez-Fernández D, Sánchez-González JR, Sánchez-Gullón E, Teodosio MA, Torralva M, Vierira-Lanero R, Oliva-Paterna FJ (2023) A horizon scan exercise for aquatic invasive alien species in Iberian inland waters. The Science of the Total Environment 869: 161798. https://doi.org/10.1016/j.scitotenv.2023.161798 Ogburn MB, Habegger LC (2015) Reproductive Status of Callinectes sapidus as an Indicator of Spawning Habitat in the South Atlantic Bight, USA. Estuaries and Coasts 38: 2059–2069. https://doi.org/10.1007/s12237-015-9962-2 Ortega I, Ibeiro CF, Rodrigues LS, Rodrigues MA, Dumont LFC (2020) Habitat use in different life and moulting stages of Callinectes sapidus (Decapoda, Portunidae) in South Brazilian estuarine and marine environments. Journal of the Marine Biological Association of the United Kingdom 100: 79–91. https://doi.org/10.1017/S0025315419001085 Ortega-Jiménez E, Cuesta JA, Laiz I, González-Ortegón E (2024) Diet of the Invasive Atlantic Blue Crab Callinectes sapidus Rathbun, 1896 (Decapoda, Portunidae) in the Guadalquivir Estuary (Spain). Estuaries and Coasts 47: 1–11. https://doi.org/10.1007/s12237-024-01344-9 Özdemir S, Gökçe G, Çekic M (2015) Determination of Size Selectivity of Traps for Blue Crab (Callinectes sapidus Rathbun, 1896) in the Mediterranean Sea. Tarim Bilimleri Dergisi 21: 256–261. https://doi.org/10.1501/Tarimbil_0000001327 Parreira F, Martínez-Crego B, Lourenço-Afonso CM, Machado M, Oliveira F, Manuel dos Santos-Gonçalves J, Santos R (2021) Biodiversity consequences of Caulerpa prolifera takeover of a coastal lagoon. Estuarine, Coastal and Shelf Science 255: 1–7. https://doi.org/10.1016/j. ecss.2021.107344 Pérez-Ruzafa Á, Marcos C, Gilabert J (2005) The ecology of the Mar Menor coastal lagoon: A fast changinc ecosystem under human pressure. In: Gönenç IE, Wolflin JP (Eds) Coastal Lagoons: Ecosystem Processes and Modeling for Sustainable Use and Development. CRC Press, Florida, 392–422. Pérez-Ruzafa Á, Marcos C, Bernal CM, Quintino V, Freitas R, Rodrigues AM, García-Sánchez M, Pérez-Ruzafa IM (2012) Cymodocea nodosa vs. Caulerpa prolifera: Causes and consequences of a long-term history of interaction in macrophyte meadows in the Mar Menor coastal lagoon (Spain, southwestern Mediterranean). Estuarine, Coastal and Shelf Science 110: 101–115. https://doi.org/10.1016/j.ecss.2012.04.004 Pérez-Ruzafa A, Campillo S, Fernández-Palacios JM, Garcia-Lacunza A, García-Oliva M, Ibañez H, Navarro-Martínez PC, Pérez-Marcos M, Pérez-Ruzafa IM, Quispe-Becerra JI, Sala-Mirete A, Sánchez O, Marcos C (2019) Long-term dynamic in nutrients, chlorophyll a, and water quality parameters in a coastal lagoon during a process of eutrophication for decades, a sudden break and a relatively rapid recovery. Frontiers in Marine Science 6: 26. https://doi.org/10.3389/fmars.2019.00026 Pérez-Ruzafa Á, Pérez-Marcos M, Marcos C (2020) Coastal lagoons in focus: Their environmental and socioeconomic importance. Journal for Nature Conservation 57: 125886. https://doi.org/10.1016/j.jnc.2020.125886 Poikane S, Salas Herrero F, Kelly MG, Borja A, Birk S, van de Bund W (2020) European aquatic ecological assessment methods: A critical review of their sensitivity to key pressures. The Science of the Total Environment 740: 140075. https://doi.org/10.1016/j. scitotenv.2020.140075 373 NeoBiota 102: 351–375 (2025), DOI: 10.3897/neobiota.102.148388 Antonio A. Herrero-Reyes et al.: Habitat use and trapping efficiency of blue crab in hypersaline coastal lagoon Prado P, Peñas A, Ibáñez C, Cabanes P, Jornet L, Álvarez N, Caiola N (2020) Prey size and species preferences in the invasive blue crab, Callinectes sapidus: Potential effects in marine and freshwater ecosystems. Estuarine, Coastal and Shelf Science 245: 106997. https://doi.org/10.1016/j.ecss.2020.106997 Prado P, Ibáñez C, Chen L, Caiola N (2022) Feeding Habits and Short-Term Mobility Patterns of Blue Crab, Callinectes sapidus, Across Invaded Habitats of the Ebro Delta Subjected to Contrasting Salinity. Estuaries and Coasts 45: 839–855. https://doi. org/10.1007/s12237-021-01004-2 Pyšek P, Hulme PE, Simberloff D, Bacher S, Blackburn TM, Carlton JT, Dawson W, Essl F, Foxcroft LC, Genovesi P, Jeschke JM, Kühn I, Liebhold AM, Mandrak NE, Meyerson LA, Pauchard A, Pergl J, Roy HE, Seebens H, van Kleunen M, Vilà M, Wingfield MJ, Richardson DM (2020) Scientists’ warning on invasive alien species. Biological Reviews of the Cambridge Philosophical Society 95: 1511–1534. https://doi. org/10.1111/brv.12627 R Core Team (2023) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. https://www.r-project.org/ Ramach S, Darnell MZ, Avissar N, Rittschof D (2009) Habitat use and population dynamics of blue cerabs, Callinectes sapidus, in a high-salinity embayment. Journal of Shellfish Research 28: 635–640. https://doi.org/10.2983/035.028.0328 Rato LD, Crespo D, Lemos MFL (2021) Mechanisms of bioinvasions by coastal crabs using integrative approaches – A conceptual review. Ecological Indicators 125: 107578. https://doi.org/10.1016/j.ecolind.2021.107578 Robledano F, Esteve MA, Calvo JF, Martínez-Paz JM, Farinós P, Carreño MF, Soto I, Avilés M, Ballesteros GA, Martínez-Baños P, Zamora A (2018) Multi-criteria assessment of a proposed ecotourism, environmental education and research infrastructure in a unique lagoon ecosystem: The Encañizadas del Mar Menor (Murcia, SE Spain). Journal for nature conservation 43: 201–210. https://doi.org/10.1016/j.jnc.2017.10.007 Roy HE, Pauchard A, Stoett P, Renard-Truong T, Bacher S, Galil BS, Hulme PE, Ikeda T, Kavileveettil S, McGeoch MA, Meyerson LA, Nuñez MA, Ordonez A, Rahlao SJ, Schwindt E, Seebens H, Sheppard AW, Vandvik V (2023) Summary for policymakers of the thematic assessment of invasive alien species and their control of the Intergovernmental Platform on Biodiversity and Ecosystem Services. https://doi.org/10.5281/ zenodo.8314303 Ruas VM, Rodrigues MA, Dumont LFC, D’Incao F (2014) Habitat selection of the pink shrimp Farfantepenaeus paulensis and the blue crab Callinectes sapidus in an estuary in southern Brazil: Influence of salinity and submerged seagrass meadows. Nauplius 22: 113–125. https://doi.org/10.1590/s0104-64972014000200005 Rueda JL, Salas C (2003) Seasonal variation of a molluscan assemblage living in a Caulerpa prolifera meadow within the inner Bay of Cádiz (SW Spain). Estuarine, Coastal and Shelf Science 57(5–6): 909–918. https://doi.org/10.1016/S0272-7714(02)00421-3 Ruiz GM, Hines AH, Posey MH (1993) Shallow water as a refuge habitat for fish and crustaceans in non-vegetated estuaries: An example from Chesapeake Bay. Marine Ecology Progress Series 99: 1–16. https://doi.org/10.3354/meps099001 Sánchez-Jerez P, Cebrián CB, Esplá AAR (1999) Comparison of the epifauna spatial distribution in Posidonia oceanica, Cymodocea nodosa and unvegetated bottoms: Importance of meadow edges. Acta Oecologica 20(4): 391–405. https://doi.org/10.1016/S1146609X(99)00128-9 Sánchez-Moyano JE, Estacio FJ, García-Adiego EM, García-Gómez JC (2001) Effect of the vegetative cycle of Caulerpa prolifera on the spatio-temporal variation of 374 NeoBiota 102: 351–375 (2025), DOI: 10.3897/neobiota.102.148388 Antonio A. Herrero-Reyes et al.: Habitat use and trapping efficiency of blue crab in hypersaline coastal lagoon invertebrate macrofauna. Aquatic Botany 70(2): 163–174. https://doi.org/10.1016/ S0304-3770(00)00144-3 Sandoz M, Rogers R (1944) The effect of environmental factors on hatching, moulting, and survival of zoea larvae of the blue crab Callinectes sapidus Rathbun. Ecology 25: 216–228. https://doi.org/10.2307/1930693 Scalici M, Chiesa S, Mancinelli G, Rontani PM, Voccia A, Nonnis Marzano F (2022) Euryhaline Aliens Invading Italian Inland Waters: The Case of the Atlantic Blue Crab Callinectes sapidus Rathbun, 1896. Applied Sciences 12(9): 4666. https://doi.org/10.3390/ app12094666 Seitz RD, Marshall Jr LS, Hines AH, Clark KL (2003) Effects of hypoxia on predator-prey dynamics of the blue crab Callinectes sapidus and the Baltic clam Macoma balthica in Chesapeake Bay. Marine Ecology Progress Series 257: 179–188. https://doi. org/10.3354/meps257179 Seitz RD, Knick KE, Westphal M (2011) Diet selectivity of juvenile blue crabs (Callinectes sapidus) in chesapeake bay. Integrative and Comparative Biology 51: 598–607. https:// doi.org/10.1093/icb/icr098 Streftaris N, Zenetos A (2006) Alien marine species in the Mediterranean - the 100 “worst invasives” and their impact. Mediterranean Marine Science 7(1): 87–118. https://doi. org/10.12681/mms.180 Taylor DL, Fehon MM (2021) Blue Crab (Callinectes sapidus) Population Structure in Southern New England Tidal Rivers: Patterns of Shallow-Water, Unvegetated Habitat Use and Quality. Estuaries and Coasts 44: 1320–1343. https://doi.org/10.1007/ s12237-020-00867-1 Taylor DL, Fehon MM, Cribari KJ, Scro AK (2022) Blue crab Callinectes sapidus dietary habits and pre dation on juvenile winter flounder Pseudopleuronectes americanus in southern New England tidal rivers. Marine Ecology Progress Series 681: 145–167. https://doi.org/10.3354/meps13909 Verdiell-Cubedo D, Oliva-Paterna FJ, Torralva-Forero M (2007) Fish assemblages associated with Cymodocea nodosa and Caulerpa prolifera meadows in the shallow areas of the Mar Menor coastal lagoon. Limnetica 26: 341–350. https://doi.org/10.23818/ limn.26.29 Vivas M, García-Rodríguez E, Muñoz-Vera A, Barcala E, Guijarro-García E (2025) Effect of the invasive blue crab (Callinectes sapidus Rathbun, 1896) in a protected coastal lagoon. Estuaries and Coasts 48: 1–13. https://doi.org/10.1007/s12237-024-01436-6 Williams AB (1954) Marine decapod crustaceans of the carolinas. Fish Bulletin 432. http://www.biodiversitylibrary.org/page/3253134 Wood SN (2011) Fast stable restricted maximum likelihood and marginal likelihood estimation of semiparametric generalized linear models. Journal of the Royal Statistical Society. Series B, Statistical Methodology 73(1): 3–36. https://doi.org/10.1111/j.14679868.2010.00749.x Zamora-Marín JM, Herrero-Reyes AA, Ruiz-Navarro A, Oliva-Paterna FJ (2023a) Non-indigenous aquatic fauna in transitional waters from the Spanish Mediterranean coast: A comprehensive assessment. Marine Pollution Bulletin 191. https://doi.org/10.1016/j. marpolbul.2023.114893 Zamora-Marín JM, Ruiz-Navarro A, Oficialdegui FJ, Anastácio PM, Miranda R, García-Murillo P, Cobo F, Ribeiro F, Gallardo B, García-Berthou E, Boix D, Medina L, Morcillo F, Oscoz J, Guillén A, Herrero-Reyes AA, Aguiar FC, Almeida D, Arias A, Ayres C, Banha F, Barca S, Biurrun I, Cabezas MP, Calero S, Campos JA, Capdevila-Argüelles L, Capinha C, Carapeto A, Casals F, Chainho P, Cirujano S, Clavero M, Cuesta 375 NeoBiota 102: 351–375 (2025), DOI: 10.3897/neobiota.102.148388 Antonio A. Herrero-Reyes et al.: Habitat use and trapping efficiency of blue crab in hypersaline coastal lagoon JA, Deltoro V, Encarnação J, Fernández-Delgado C, Franco J, García-Meseguer AJ, Guareschi S, Guerrero-Gómez A, Hermoso V, López-Cañizares C, López-Soriano J, Machordom A, Martelo J, Mellado-Díaz A, Moreno JC, Olivo del Amo R, Otero JC, Perdices A, Pou-Rovira Q, Quiñonero-Salgado S, Rodríguez-Merino A, Ros M, Sánchez-Gullón E, Sánchez MI, Sánchez-Fernández D, Sánchez-González JR, Soriano O, Teodósio MA, Torralva M, Vieira-Lanero R, Zamora-López A, Oliva-Paterna FJ (2023b) A multi-taxa assessment of aquatic non-indigenous species introduced into Iberian freshwater and transitional waters. NeoBiota 89: 17–44. https://doi.org/10.3897/ neobiota.89.105994 Zenni RD, Essl F, García-Berthou E, McDermott SM (2021) The economic costs of biological invasions around the world. NeoBiota 67: 1–9. https://doi.org/10.3897/neobiota.67.69971 Supplementary material 1 Supplementary information Authors: Antonio A. Herrero-Reyes, Adrián Guerrero-Gómez, Antonio Zamora-López, Mar Torralva, José M. Zamora-Marín, Francisco J. Oliva-Paterna Data type: docx Copyright notice: This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited. Link: https://doi.org/10.3897/neobiota.102.148388.suppl1