Carles Alcaraz

• Ph.D.
• Researcher at IRTA Institute of Agrifood Research and Technology

The mosquitofish (Gambusia holbrooki) is among the most invasive fish worldwide, with well documented ecological impacts on ecosystem functioning and several native taxa. Although it has been suggested that salinity limits the invasive success of mosquitofish, there are few studies on how salinity affects its ecology. We examined differences in lif...

We report the first data on the use of occasionally inundated habitats in a Mediterranean coastal lagoon by the Spanish toothcarp (Aphanius iberus), a cyprinodontid fish in danger of extinction. During a flooding period, we sampled the fish population and the macroinvertebrate community in three contrasting habitats: mats of green algae, open water...

Reversed eutrophication, called oligotrophication, has widely been documented globally over the last 30 years in rivers, lakes, and estuaries. However, the absence of a comprehensive and harmonized dataset has hindered a deeper understanding of its ecological consequences. To address this data gap, we developed the OLIGOTREND database, which contai...

δ¹³C and δ¹⁵N patterns of the blue crab, Callinectes sapidus, and its potential diets, were investigated in eleven localities within four invaded regions of the Spanish Mediterranean (Catalonia, Valencia, Alicante, and Murcia) subjected to contrasting salinities and degrees of connectivity with the open sea. These regions host blue crab fisheries o...

Although variation in effect sizes and predicted values among studies of similar phenomena is inevitable, such variation far exceeds what might be produced by sampling error alone. One possible explanation for variation among results is differences among researchers in the decisions they make regarding statistical analyses. A growing array of studi...

Ecological restoration of non-productive agricultural areas such as field margins has been identified as a key priority to enhance biodiversity and promote multiple ecosystem services within agroecosystems. Field margin restoration is especially important in rice (Oryza sativa, L), a globally important crop which occupies around 15 % of world cropl...

Global change is eroding freshwater biodiversity at higher rates than in any other ecosystem, potentially entailing a parallel degradation of ecosystem functions such as the predation function. However, the relationships between biodiversity and predation effectiveness remain poorly explored in freshwater ecosystems, largely due to the unavailabili...

La vulnerabilidad social ante el cambio climático en el ámbito costero es un tema crucial. Los ciudadanos que viven en estas áreas son conocedores del medio y experimentan directamente los efectos del cambio climático. Escuchar sus opiniones y propuestas debería ser un requisito obligatorio en la puesta en marcha de políticas de gestión integral. L...

Persistent viral infection is a condition of metastability in which the pathogen and the host coexist, where viral replication is held in check, but not cleared. With a clear benefit for the virus at the population level, persistent infections can act as ecosystem modulators (Villareal et al., 2009). Along with the recurring infection goes cell dam...

The European Fish Index EFI+ is the only fish-based multimetric index for the assessment of the ecological status of running waters that is validated and thus applicable across most countries of the European Union. Metrics of the index rely on several attributes of the species present in the fish assemblage, irrespective of their native/alien statu...

The European Fish Index EFI+ is the only fish-based multimetric index for the assessment of the ecological status of running waters validated and thus applicable across the European Union. Metrics of the index rely on several attributes of the species present in the fish assemblage, irrespective of their native/alien status. The abundance of alien...

Although variation in effect sizes and predicted values among studies of similar phenomena is inevitable, such variation far exceeds what might be produced by sampling error alone. One possible explanation for variation among results is differences among researchers in the decisions they make regarding statistical analyses. A growing array of studi...

Rice cultivation is popular in low-lying areas such as deltas, but climate change threatens the viability of the crop. In recent decades, the resilience of deltas to sea level rise (SLR) has been influenced by the reduction of sediment load from rivers due to the construction of dams, disrupting natural deposition in deltaic plains. Sediment and or...

Paddy farming can potentially sequester carbon. However, agricultural practices may alter the stability of the soil organic carbon (SOC) stocks and thereby increase carbon mobilization in the topsoil and subsoil. We hypothesize that both agricultural practices and soil physical–chemical characteristics, mostly those related to the type of the paren...

Direct consequences of biological invasions on biodiversity and the environment have been largely documented. Yet collateral indirect effects mediated by changes in agri-environmental policies aimed at combating invasions remain little explored. Here we assessed the effects of recent changes in water management in rice farming, which are aimed at b...

Rice cultivation is a major source of methane (CH4) emissions. Intermittent irrigation systems in rice cultivation, such as the mid-season drainage (MSD), are effective strategies to mitigate CH4 emissions during the growing season, though the reduction rates are variable and dependent on the crop context. Aeration periods induce alteration of soil...

Dwarf oysters in the Ebro Delta are only observed growing on local pen shells, Pinna nobilis L., currently under extinction risk. The species identification of these populations is uncertain, given recent genetic classifications of dwarf oysters of Ostrea stentina species complex. Hence, the first objective of this study was to confirm the identity...

Short extreme events have significant impact on landscape and ecosystems in low-lying and exposed areas such as deltaic systems. In this context, this paper proposes a combined methodology for the mapping and monitoring of the flooding and water quality dynamics of coastal areas under extreme storms from Sentinel 2 imagery. The proposed methodology...

Aims To assess 1) the effect of the combination of flooding (winter flooding vs. non-winter flooding; WFL vs NWF) and timing of straw incorporation (early vs late straw incorporation; ESI vs LSI) in the post-harvest of paddy agrosystem, on a year-round global balance of greenhouse gases (GHG) exchanges, i.e. methane (CH4), carbon dioxide (CO2) and...

We provide a unique fish individual body size dataset collected from our own sampling and public sources in north-eastern Spain. The dataset includes individual body size measures (fork length and mass) of 12,288 individuals of 24 fish species within 10 families collected at 118 locations in large rivers and small streams. Fish were caught by one-p...

The Mediterranean brown trout (Salmo trutta complex) is native to basins draining to the Western Mediterranean Sea, and natural populations are currently declining in abundance and distribution due to habitat degradation and introgression with stocked trout of the Atlantic lineage. Data on its life history traits are limited, although is an essenti...

The future success of rice farming will lie in developing productive, sustainable, and resilient farming systems in relation to coexistent ecosystems. Thus, accurate information on agricultural practices and grain yield at optimum temporal and spatial scales is crucial. This study evaluates the potential application of Sentinel-2 (S2) to monitor th...

Sentinel-2 offers great potential for monitoring water quality in inland and coastal waters. However, atmospheric correction in these waters is challenging, and there is no standardized approach yet, but different methods coexist under constant development. The atmospheric correction Case 2 Regional Coast Colour (C2RCC) processor has been recently...

Sea level rise (SLR) is threatening low-lying coastal areas such as river deltas. The Ebro river Delta (Spain) is representative of coastal systems particularly vulnerable to SLR due to significant sediment retention behind upstream dams (up to 99%), thereby dramatically reducing the capacity for deltaic sediment accretion. Rice production is the m...

Dinoflagellates of the genera Prorocentrum and Dinophysis are known producers of toxic compounds belonging to the okadaic acid (OA) group. The ingestion of shellfish contaminated with these toxins causes a human disease named diarrheic shellfish poisoning (DSP). In this study, the first record of Prorocentrum panamense, a potential toxin‐producer s...

Gull eggs are excellent bioindicators of environmental pollution as reflect the contamination levels of coastal areas, especially of persistent and bioacumulative compounds such as perfluoroalkyl substances (PFAS). This study aims to evaluate the geographical distribution and 10-year temporal trends (2009–2018) of 17 PFAS in eggs of two gull specie...

The AWD is an irrigation technology for rice cultivation, consisting in implementing alternate draining and flooded periods over the growing season, that delivers multiple environmental benefits, such as reduced water consumption, CH4 emissions and arsenic (As) grain content, but can be offset by yield losses. The trade-offs between the agronomic a...

Cyclodextrins, cyclic oligomers that form a conical structure with an internal cavity, are proposed as new and sustainable materials for passive sampling of lipophilic marine toxins. Two applicability scenarios have been tested. First, disks containing β-cyclodextrin-hexamethylene diisocyanate (β-CD-HDI) and β-cyclodextrin-epichlorohydrin (β-CD-EPI...

Dinoflagellates of the genera Gambierdiscus and Fukuyoa are known to produce several bioactive compounds including the potent neurotoxic ciguatoxins (CTXs) which are able to accumulate in fish and through the food web. When humans ingest fish contaminated with CTXs, it can result in an intoxication named ciguatera. Although not all the currently re...

The effects of dietary phospholipids (PL) on the performance of juvenile stellate sturgeon (Acipenser stellatus) was evaluated in terms of growth and feed efficiency parameters, muscle and liver fatty acid profiles, activity of digestive and antioxidative stress enzymes, and expression of lipoprotein lipase (lpl) and insulin-like growth factor (igf...

Purpose To assess 1) the cumulative greenhouse gas emissions –GHG- and global warming potential (methane – CH 4 - and nitrous oxide) from rice fields in the growing and fallow seasons, and 2) the environmental and agronomic drivers of CH 4 emissions, and their relative capacity to explain CH 4 variation. Methods A two-year multisite field experime...

Consumption of seafood contaminated with ciguatoxins (CTXs) leads to a foodborne disease known as ciguatera. Primary producers of CTXs are epibenthic dinoflagellates of the genera Gambierdiscus and Fukuyoa. In this study, thirteen Gambierdiscus and Fukuyoa strains were cultured, harvested at exponential phase, and CTXs were extracted with an implem...

Coastal regions are highly dynamic and productive ecosystems with high ecological and economical value. Given the co-existence and interaction of different human activities, both in land and on sea, it is apriority an Integrated Coastal Management (ICM) ensuring their sustainability. In this sense, in the biosphere reserve of the Ebro Delta (NW Med...

The importance of ciguatoxins (CTXs) in seafood safety and their emerging occurrence in locations far away from tropical areas highlight the need for simple and low-cost methods for the sensitive and rapid detection of these potent marine toxins to protect seafood consumers. Herein, an electrochemical immunosensor for the detection of CTXs is prese...

The assessment of population structure and genetic diversity is crucial for the management and conservation of threatened species. Natural and artificial barriers to dispersal (i.e., gene flow) increase populations’ differentiation and isolation by reducing genetic exchange and diversity. Freshwater ecosystems are highly fragmented because of human...

Seagrass are marine flowering plants that form extensive meadows in shallow coastal waters. They play a critical role in coastal ecosystems by providing food and shelter for animals, recycling nutrients, and stabilizing sediments. Therefore, they are widely used as an ideal biological indicator for assessing the health status and quality of coastal...

Shellfish aquaculture has a major socioeconomic impact on coastal areas, thus it is necessary to develop support tools for its management. In this sense, phytoplankton monitoring is crucial, as it is the main source of food for shellfish farming. The aim of this study was to assess the applicability of Sentinel 2 multispectral imagery (MSI) to moni...

Ciguatera fish poisoning (CFP) is one of the most relevant seafood-borne illnesses worldwide. It is caused by the ingestion of fish contaminated by ciguatoxins (CTXs). Primary producers of CTXs are dinoflagellates of the genera Gambierdiscus and Fukuyoa. This study is focused on the development of bioanalytical tools for the detection of Gambierdis...

Ostreopsis cf. ovata is a benthic microalga distributed in tropical and temperate regions worldwide which produces palytoxins (PlTXs). Herein, an electrochemical biosensor for the detection of this toxic microalga is described. The detection strategy involves isothermal recombinase polymerase amplification (RPA) of the target using tailed primers a...

With the purpose of finding a suitable methodology for chl-a monitoring at Ebro Delta bays using space-borne remote sensing, this study aims to explore the performance of the Sentinel-2 multispectral instrument (S2/MSI) spectral bands and the derived spectral indices for chl-a retrieval. The proposed approach uses both TOA and bottom of atmosphere...

Ostreopsis is a toxic benthic dinoflagellate largely distributed worldwide in tropical and temperate areas. In the Mediterranean Sea, periodic summer blooms have been reported and have become a serious concern due to their direct impact on human health and the environment. Current microalgae identification is performed via light microscopy, which i...

Radiotelemetry was used to investigate seasonal movement and home range of brown trout Salmo trutta (size range 188–420 mm fork length, N = 30) in two reaches of the Noguera Pallaresa River (Ebro Basin, north‐east Spain) subjected to different flow regulation schemes. NP‐1 reach is a bypassed section with near natural flow conditions, whereas the d...

River deltas are ecologically and economically valuable coastal ecosystems but low elevations make them extremely sensitive to relative sea level rise (RSLR), i.e. the combined effects of sea level rise and subsidence. Most deltas are subjected to extensive human exploitation, which has altered the habitat composition, connectivity and geomorpholog...

Dispersal is a critical determinant of animal distribution and population dynamics, and is essential information for management planning. We studied the movement patterns and the influence of habitat and biotic factors on Mediterranean brown trout ( Salmo trutta ) by mark-recapture methods in three headwater streams of the Ebro Basin (NE Iberian Pe...

[This corrects the article DOI: 10.1371/journal.pone.0198081.].

Paddy rice fields are one of the most important sources of anthropogenic methane. Improving the accuracy in the CH4 budget is fundamental to identify strategies to mitigate climate change. Such improvement requires a mechanistic understanding of the complex interactions between environmental and agronomic factors determining CH4 emissions, and also...

Monthly emission rates of C-CH4 (average, mg m-2 h-1, ± SE) in each monitored commercial rice field (P1 –P15) in the growing season, from May to September (Top), and in the fallow season, from October to December (Bellow). (TIF)

Kellogg’s-LIFE agreement for sampling rice fields. (PDF)

2015_CH4 Ebre Delta Raw data. (XLSX)

El Delta del Ebro (Cataluña, España) es uno de los humedales más importantes y complejos en el Mediterráneo occidental; el 65% (4,700ha) de su superficie total se destina al cultivo de arroz. Los arrozales son una fuente importante de emisiones de gases de efecto invernadero (GEI), ya que contribuyen de un 5 al 20% de las emisiones antropogénicas g...

To study the influence of temperature (4, 6, and 12 °C) on the development of brown trout (Salmo trutta) from hatching to the end of metamorphosis, an analysis of allometric growth patterns was conducted to identify two different groups of individuals, namely developmental phases at total lengths (TL) ranging from 2.72 cm at 4 °C to 2.22 cm at 12 °...

El arroz cultivado en condiciones de inundación es uno de los principales contribuyentes a las emisiones antropogénicas de gases de efecto invernadero (GHG), en particular el metano (CH4). El proyecto Life + EBRO-ADMICLIM (2014-2018) pone en marcha acciones piloto de adaptación y mitigación del cambio climático en el delta del Ebro (Cataluña, Españ...

The hydrological connectivity between the salt marsh and the sea was partially restored in a Mediterranean wetland containing isolated ponds resulting from former salt extraction and aquaculture activities. A preliminary assessment provided evidence that ponds farther from the sea hosted very large numbers of the endangered Spanish toothcarp, Aphan...

Fish abundances per year and zone. Abundances of fish species at each study year and zone. Each row indicates numbers of individuals within a given fykenet.

Supplemental data in cohort analysis of Aphanius iberus.

Annex I. Temporal changes in the study area. (A) In 1860, the northern coast of the Alfacs Bay (see also Fig. 1) was fully fingered by salt marsh which connected with a much larger lacunar system (nowadays the Encanyissada and Tancada lagoons constitute remaining portions). (B) In 1927 to (C) 1954, the salt pans were already built but the loss of s...

Multivariate allometry patterns and length at metamorphosis (Lm) were determined in Acipenser stellatus by means of principal component analysis from 12 morphometric characters. The multivariate analysis differentiated three growth stanzas: the prelarval, larval, and early juvenile stages. The prelarval stage comprised the period from hatching (9.7...

The zebra mussel (Dreissena polymorpha Pallas, 1771) and the quagga mussel (D. rostriformis Deshayes, 1838) are successful invasive bivalves with substantial ecological and economic impacts in freshwater systems once they become established. Since their eradication is extremely difficult, their detection at an early stage is crucial to prevent spre...

Climate change and sea level rise (SLR) are global impacts threatening the sustainability of coastal territories and valuable ecosystems such as deltas. The Ebro Delta is representative of the vulnerability of coastal areas to SLR. Rice cultivation is the main economic activity in the region. Rice fields occupy most of the delta (ca. 65%) and are v...

The aim of this work was to characterize stress coping styles of Senegalese sole (Solea senegalensis) juveniles and breeders and to select an operational behavioural screening test (OBST) that can be used by the aquaculture industry to classify and select between behavioural phenotypes in order to improve production indicators. A total of 61 juveni...

The hydrological connectivity between the salt marsh and the sea was partially restored in a Mediterranean wetland containing isolated ponds resulting from former salt extraction and aquaculture activities. A preliminary assessment provided evidence that ponds farther from the sea hosted very large numbers of the endangered Spanish toothcarp, Aphan...

The hydrological connectivity between the salt marsh and the sea was partially restored in a Mediterranean wetland containing isolated ponds resulting from former salt extraction and aquaculture activities. A preliminary assessment provided evidence that ponds farther from the sea hosted very large numbers of the endangered Spanish toothcarp, Aphan...

The aim of this work was to characterize stress coping styles of Senegalese sole (Solea senegalensis) juveniles and breeders and to select an operational behavioural screening test (OBST) that can be used by the aquaculture industry to classify and select between behavioural phenotypes in order to improve production indicators. A total of 61 juveni...

Peixos continentals de Catalunya (Inland fish of Catalunya) is the first book exclusively dedicated to the fish of the fluvial systems of Catalunya, and is the result of many years of enthusiastic dedication to learning about the country’s inland fish and the ecology of the habitats in which they live. The main part of the book is concerned with th...

Among coastal systems, deltas are particularly sensitive to relative sea-level rise (RSLR) where the risk is exacerbated because of land subsidence and anthropogenic pressures (e.g. land uses, levees or dikes). RSLR threats deltaic areas with flooding, salt stress, wetland loss and decreased agricultural production. The Ebro Delta (320 km2) is one...

The combined effects of temperature and seawater acidification were investigated across larval stages of the European flat oyster Ostrea edulis, from veliger sizes released by gravid individuals to spat. Simultaneous experiments were also conducted to investigate the potential effects of reduced pH levels on bacterial growth that could provide a mo...

1. Studies quantifying the content of fine particulate matter (organic and inorganic) retained in macrophyte stands are scarce. Thus, little is known about the relationship between retention of fine particulate matter and macrophyte architecture, especially in rivers. Here, we quantified the amount of organic and inorganic fine particulate matter r...

The spatial distribution of benthic macroinvertebrate community in relation to environmental factors was studied along the Ebro Estuary (NE Iberian Peninsula), a salt wedge Mediterranean estuary. Both ordination methods and generalized additive models were performed to identify the different benthic assemblages and their relationship to abiotic fac...

Freshwater ecosystems are among the most affected by anthropogenic disturbances, and fish have several advantages for monitoring them, such as the response at larger temporal and spatial scales and its visibility to the society. This chapter summarizes our experience in developing fish-based indices in Catalonia. We describe some differences observ...

Non-native fishes are known to cause economic damage to human society and are considered a major threat to biodiversity loss in freshwater ecosystems. The growing concern about these impacts has driven to an investigation of the biological traits that facilitate the establishment of non-native fish. However, invalid assessment in choosing the appro...

Abstract: Trophic ecology is essential to understand ecosystem functioning and structure and assist biological conservation. Here we investigate, for the first time, the feeding ecology of Aphanius farsicus, a cyprinodontid fish endemic of a single landlocked river basin in central Iran. We sampled monthly a population of this fish species during a...

Biodiversity is currently declining in the Med-iterranean, particularly in freshwater ecosystems. The Iberian Peninsula is not an exception with many fish species threatened or endangered. This is the case of Parachondrostoma arrigonis, which has experienced a marked reduction of more than 80 % in both number and area of occupancy in the last 20 ye...

The zebra mussel, Dreissena polymorpha, is among the most invasive organisms worldwide, with well-documented economic and ecological impacts. In Spain, it was first detected in the Riba-roja Reservoir (Ebro River) in the summer of 2001. Although it has been suggested that mussel density determines its invasiveness and impact, there are few studies...

Hatchery reared beluga (Huso huso) were observed from hatching until the juvenile stage in order to analyse their early development and allometric growth patterns using bivariate and multivariate allometric analyses for different body regions (e.g. head, trunk, tail) and test whether there existed similarities in the growth patterns of beluga compa...

River deltas are of paramount importance in terms of ecological and economic values. They are characterized as having fertile soils, and are consequently well-endowed for agricultural production. A significant portion of rice is produced in deltaic areas, especially in Southeast Asia and the Mediterranean. Deltas are particularly sensitive to globa...

We report the first description of the ontogenic development of the axial skeleton and unpaired fins of hatchery reared bay snook (Petenia splendida, Perciformes: Cichlidae) from hatching (5.3–5.5 mm in standard length, SL) to the juvenile stage (16.1–17.5 mm SL) by means of alcian blue-alizarin red staining. The study of axial skeleton development...

Allometric growth and ontogeny were studied in thick-lipped grey mullet Chelon labrosus reared in mesocosms from 1 to 71 day post hatching (dph). Multivariate allometric analysis of morphometric growth distinguished three distinct developmental stanzas separated by two morphometric metamorphosis lengths (Lm1 = 4.46 ± 0.06 mm; Lm2 = 28.56 ± 1.04 mm)...

Fish communities of the estuarine areas of the Ter and Daró rivers is very similar to the closest estuarine area of the Fluvià-Muga. Compared to other Mediterranean estuaries such as the Ebro delta, the fish community of Ter-Daró is relatively poor. The missing species compared to the Ebro delta are mostly of marine colonization. Unlike the Ebro es...

Suspended load dynamics were analyzed for the period 2007-2009 in a semi-meandering cross-section under different hydrological conditions. Samples were collected at four different points of the cross-section. During "low discharges" (≤ 600 m³/s) suspended load samples were collected at-a-monthly basis, whereas at "high discharges" (> 600 m³/s) samp...

The knowledge of capture efficiency and side effects of electrofishing is essential for research and monitoring of stream fish populations. Differences amongst electrofishing crews have hardly been investigated and are particularly important given the on-going implementation of the Water Framework Directive and wide-ranging exchange of data worldwi...

We experimentally examined the predator-prey relationships between juvenile spotted sorubim Pseudoplastystoma corruscans and young-of-the-year invasive and native fish species of the Paraná River basin, Brazil. Three invasive (peacock bass Cichla piquiti, Nile tilapia Oreochromis niloticus, and channel catfish Ictalurus punctatus) and two native (y...

The lower Ebro River (Catalonia, Spain) has recently undergone a regime shift from a phytoplankton dominated to a macrophyte-dominated system. This shift is well known in shallow lakes but apparently it has never been documented in rivers. Two initial hypotheses to explain the collapse of the phytoplankton were considered: a) the diminution of nutr...