First record of intraspecific cleaning behavior by the threatened Leuciscidae Squalius alburnoides (Steindachner, 1866) at the Guadiana River basin (Portugal).

Squalius alburnoides (Steindachner, 1866) is an endemic threatened species from the Iberian Peninsula. Here, we report the first observations of intraspecific cleaning behavior in isolated summer pools in the Guadiana River Basin (Portugal). We found that focal S. alburnoides solicited cleaning by adopting an immobile tail-stand position known as "posing," which immediately signaled a response to a few conspecifics that approached and inspect them. Our study expands the list of cleanerfish species in freshwaters, giving emphasis to the importance of mutual positive behavior within an endangered species, particularly when facing seasonal disturbance.

A horizon scan exercise for aquatic invasive alien species in Iberian inland waters.

As the number of introduced species keeps increasing unabatedly, identifying and prioritising current and potential Invasive Alien Species (IAS) has become essential to manage them. Horizon Scanning (HS), defined as an exploration of potential threats, is considered a fundamental component of IAS management. By combining scientific knowledge on taxa with expert opinion, we identified the most relevant aquatic IAS in the Iberian Peninsula, i.e., those with the greatest geographic extent (or probability of introduction), severe ecological, economic and human health impacts, greatest difficulty and acceptability of management. We highlighted the 126 most relevant IAS already present in Iberian inland waters (i.e., Concern list) and 89 with a high probability of being introduced in the near future (i.e., Alert list), of which 24 and 10 IAS, respectively, were considered as a management priority after receiving the highest scores in the expert assessment (i.e., top-ranked IAS). In both lists, aquatic IAS belonging to the four thematic groups (plants, freshwater invertebrates, estuarine invertebrates, and vertebrates) were identified as having been introduced through various pathways from different regions of the world and classified according to their main functional feeding groups. Also, the latest update of the list of IAS of Union concern pursuant to Regulation (EU) No 1143/2014 includes only 12 top-ranked IAS identified for the Iberian Peninsula, while the national lists incorporate the vast majority of them. This fact underlines the great importance of taxa prioritisation exercises at biogeographical scales as a step prior to risk analyses and their inclusion in national lists. This HS provides a robust assessment and a cost-effective strategy for decision-makers and stakeholders to prioritise the use of limited resources for IAS prevention and management. Although applied at a transnational level in a European biodiversity hotspot, this approach is designed for potential application at any geographical or administrative scale, including the continental one.

Hemolymph Glycemia as an Environmental Stress Biomarker in the Invasive Red Swamp Crayfish (Procambarus clarkii).

AbstractSeveral freshwater crayfish species, including Procambarus clarkii, are both ecologically important and commercially important benthic macroinvertebrates, remarkable for their potential to adapt and reproduce but also for their unique abilities to face distinct abiotic and biotic environments and become successful invaders. While much work has been done to study crayfish introductions, less focus has been given to how crayfish cope with pollution and other environmental stressors, in terms of physiological responses, and whether crayfish responses can be used to assess the effective state of their living environment. Here, we used a mixed approach combining laboratory experiments with field data to validate the use of hemolymph glucose as a relevant biomarker of red swamp crayfish (Procambarus clarkii) stress response. Three meaningful sampling locations were chosen across southern Portugal that are representative of different environments where crayfish live and are frequently captured for human consumption but also correspond to different pollution levels. To reference field measurements of glucose levels, we performed two lab-based experiments: (a) crayfish were exposed to different levels of stress (stress challenge) and (b) crawfish were exposed to a maze dispersal test, with or without water. Crayfish glucose levels were responsive to induced stress but were not correlated with dispersal efforts. Wild crayfish's body condition and stress levels responded differently to environmental conditions, with more challenged individuals showing higher glycemia levels but similar body condition. The glucose levels of the more stressed wild crayfish were visually similar to lab-based crayfish subjected to the higher stress levels (electric shocks), while the levels of glucose of crayfish at the less polluted site corresponded to those measured before the start of the challenge (baseline). The maintenance of high levels of glycemia in crayfish inhabiting more challenging habitats is revealing of their higher energetic demand state. Since P. clarkii ia globally distributed and easily sampled invasive species, quantifying its hemolymph glucose levels can be a particularly useful proxy for assessing environmental quality.

Perceptions and risk behaviors regarding biological invasions in inland aquatic ecosystems.

Public engagement is vital to effectively manage Invasive Alien Species (IAS) and biosecurity campaigns directed to stakeholders are decisive to raise awareness regarding IAS regulations and problems. To design and implement adequate communication plans, stakeholders' perceptions and risk behaviors regarding IAS need to be monitored by surveys. IAS do not recognize borders and most countries are not biogeographically isolated. Therefore, international information and consensus are necessary when applying measures at a biogeographic scale. Our bilingual survey was performed at the Iberian Peninsula, targeting the general public, decision-makers and other stakeholders, covering all taxa associated to inland aquatic ecosystems. We found differences in IAS' awareness between countries, and between different stakeholder groups. Results showed that the awareness of socioeconomic and human health impacts is substantially lower when compared with impacts on biodiversity. We found that the perception regarding the predation impacts is consistent across groups and countries, while other perceptions differ. The negative socioeconomic impact on angling due to IAS introductions is widely recognized. However, angling is also the activity most referred as positively impacted by IAS due to fish introductions. Most responders knew what IAS are, providing correct species examples. For all three awareness types (Biodiversity, Socio-economic and Human health) the model regressions showed that the most important predictor was the country of provenance of the respondent, followed by Education level for the socio-economic and biodiversity regressions and the stakeholder group in the Human health regression. We can conclude that in Portugal and Spain the general public and other key target-groups have reduced understanding of some threats posed by IAS. We highlight that raising awareness about IAS impacts on humans, namely on socio-economic aspects and human health, may be more effective and it is certainly needed in education campaigns towards IAS.

Emotional behavior in aquatic organisms? Lessons from crayfish and zebrafish.

Experimental animal models are a valuable tool to study the neurobiology of emotional behavior and mechanisms underlying human affective disorders. Mounting evidence suggests that various aquatic organisms, including both vertebrate (e.g., zebrafish) and invertebrate (e.g., crayfish) species, may be relevant to study animal emotional response and its deficits. Ideally, model organisms of disease should possess considerable genetic and physiological homology to mammals, display robust behavioral and physiological responses to stress, and should be sensitive to a wide range of drugs known to modulate stress and affective behaviors. Here, we summarize recent findings in the field of zebrafish- and crayfish-based tests of stress, anxiety, aggressiveness and social preference, and discuss further perspectives of using these novel model organisms in translational biological psychiatry. Outlining the remaining questions in this field, we also emphasize the need in further development and a wider use of crayfish and zebrafish models to study the pathogenesis of affective disorders.

Non-native freshwater fauna in Portugal: A review.

We present the most updated list of non-native freshwater fauna established in Portugal, including the Azores and Madeira archipelagos. This list includes 67 species at national level but corresponds to 84 species records, of which 53 are in the mainland, 23 in the Azores and 8 in Madeira archipelagos. We also discuss the progression of the cumulative number of introductions since 1800 and identify the most probable vectors of introduction, main taxonomic groups and their regions of origin. Furthermore, we review the existing knowledge about ecological and economic impacts, invasion risk and potential distribution of invaders, under present and future climatic conditions, and the applied management actions, including the production of legislation. Along the 20th century the number of successful introductions increased at an approximate rate of two new species per decade until the beginning of 1970s. Since then, this rate increased to about 14 new species per decade. These introductions were mainly a result of fisheries, as contaminants or for ornamental purposes. Fish and mollusks are the taxonomic groups with more established species, representing more than half of the total. Most species (>70%) are native from other regions of Europe and North America. Studies about ecological or socioeconomic impacts are more common for fish, crustaceans and mollusks. Impacts for most amphibians, reptiles and mammals are not thoroughly studied. A few studies on the impacts and management actions of health-threatening mosquitoes are also available. The potential distribution in the Portuguese territory was modelled for 26 species. Only a minority of these models provides projections of distributions under scenarios of future climate change. A comparison of the Portuguese and EU legislation shows large discrepancies in the invasive species lists. Using the EU list and a ranking procedure for the national context, we identify freshwater species of high national concern for which actions are urgently needed.