Tea Bašić

Centre for Environment, Fisheries and Aquaculture Science | CEFAS

Anadromous salmonids migrate seaward to exploit feeding and growth opportunities in marine habitats, yet how smolt biological characteristics influence their marine migratory behavior remains poorly understood. This study used 9 years of trout (Salmo trutta) population monitoring data from 15,595 tagged age‐0+ parr, 1033 smolts detected migrating d...

In recent decades, the population of European eel Anguilla anguilla has strongly declined and the stock is outside safe biological limits. Freshwater habitat degradation has been cited as a key causal factor in the European eel decline, but there are limited studies assessing the responses of this species to river habitat restoration efforts. This...

The challenge of managing aquatic connectivity in a changing climate is exacerbated in the presence of additional anthropogenic stressors, social factors, and economic drivers. Here we discuss these issues in the context of structural and functional connectivity for aquatic biodiversity, specifically fish, in both the freshwater and marine realms....

Eel Management Plans demand European silver eel (Anguilla anguilla) escapement to the sea of at least 40% of that expected historically in the absence of human impacts. Landlocked lentic waterbodies, such as drinking water reservoirs, host substantial numbers of eel, which could represent a significant contribution to catchment-based conservation t...

WKSMEEL is part of the roadmap defined by the WKFEA (Workshop on the future of eel advice). Experts from Japan, USA, Canada and Europe met to discuss modelling methods and the data necessary to support the development of a spatial assessment of the stock of European eel (Anguilla anguilla). Modelling of the European eel stock is envisioned as a two...

Atlantic salmon Salmo salar is a socio-economically important anadromous fish species that has suffered synchronous population declines around the North Atlantic over the last five decades. Reduced marine survival has been implicated as a key driver of the declines, yet the relative importance of different stressors causing mortality at sea is not...

Fish somatic growth is indeterminate and can be influenced by a range of abiotic and biotic variables. With climate change forecast to increase the frequency of warming and unusual discharge events, it is thus important to understand how these variables currently influence somatic growth and how that might differ for specific age-classes and/ or li...

The Joint EIFAAC/ICES/GFCM Working group on eels (WGEEL) met by correspondence and video conference from September 7 – 10 September and 27 September – 4 October in 2021 to assess the state of the European eel and its fisheries, investigate the effects of contaminants on the reproductive capacity of the eel stock, discuss the findings of WKFEA, furt...

Globally, inland waters emit over 2 Pg of carbon per year as carbon dioxide, of which the majority originates from streams and rivers. Despite the global significance of fluvial carbon dioxide emissions, little is known about their diel dynamics. Here we present a large-scale assessment of day- and night-time carbon dioxide fluxes at the water-air...

The cover image is based on the Short Communication The potential contribution of small coastal streams to the conservation of declining and threatened diadromous fishes, especially the European eel by Gordon Copp et al., https://doi.org/10.1002/rra.3746. Photography by Alan Walker.

Human-generated pressures are continuing to have a detrimental effect on diadro-mous fishes, resulting in legislative initiatives to conserve and manage these species. Field studies to inform these initiatives focus almost exclusively on larger marine, estuarine, and inland waters, neglecting the role of small coastal streams and tributaries in pop...

Environmental changes due to non-native species introductions and translocations are a global concern. Whilst understanding the causes of bioinvasions is important, there is need for decision-support tools that facilitate effective communication of the potential risks of invasive non-native species to stakeholders. Decision-support tools have been...

Environmental changes due to non-native species introductions and translocations are a global concern. Whilst understanding the causes of bioinvasions is important, there is need for decision-support tools that facilitate effective communication of the potential risks of invasive non-native species to stakeholders. Decision-support tools have been...

Suitable gravel availability is critical for the spawning success of lithophilous fishes, including redd builders. Redd construction during spawning can alter substrate characteristics, thereby influencing hydraulic conditions and sediment transport, highlighting the importance of spawning as a zoogeomorphic activity. Here, interactions between red...

Conservation of the critically endangered European eel Anguilla anguilla (Linnaeus, 1758) requires knowledge of silver eel escapement across all eel-producing habitats. Describing eel production from deep waters is especially challenging, thus telemetry studies can be used to detect specific behavioural patterns and aid in designing cost-effective...

Assessments of the trophic consequences of invasive fishes are important for quantifying their ecological impacts on native species more generally. A small-bodied cyprinid fish native to continental Europe and introduced in the 1970s to the U.K, the sunbleak Leuciscus delineatus, has been shown previously to establish closer social associations wit...

The spawning success of lithophilic salmonids is strongly influenced by the fine sediment content (“fines”) of spawning substrates, yet knowledge on the impacts of fines on the spawning of non‐salmonid lithophiles remains limited, despite their ecological and socio‐economic importance in European rivers. Consequently, the aim here was to use an ex‐...

Recruitment of salmonids is a result of density‐dependent factors, specifically egg production in the previous year, and density‐independent environmental processes driven by discharge and temperature. With the plethora of knowledge on major drivers of Atlantic salmon Salmo salar and brown trout Salmo trutta recruitment, there is a requirement to e...

Fine sediments can impact river biota, with egg and larval stages of lithophilic fish particularly sensitive to deposition of sand- to clay-sized particles (‘fines’) in spawning gravels. Mitigation and restoration methods include jetting to cleanse gravels of fines. Despite wide application, impacts of jetting on gravel composition and quality have...

The crossing of freshwater ecosystem boundaries by marine-derived nutrients (MDN) is usually associated with migratory salmonid fishes returning to natal rivers. An alternative source of MDN in fresh waters is the widespread use of pelletised marine fishmeal (“pellets”) by freshwater anglers as they target large-bodied cyprinid fishes, such as Euro...

Hatchery-reared fish are commonly stocked into freshwaters to enhance recreational angling. As these fishes are often of high trophic position and attain relatively large sizes, they potentially interact with functionally similar resident fishes and modify food-web structure. Hatchery-reared barbel Barbus barbus are frequently stocked to enhance ri...

Anthropogenic inputs of fine sediments into freshwater systems can have deleterious effects on freshwater habitats and biota. With regard to lithophilic fish species, fine sediment accrual on and ingress into spawning gravels can detrimentally impact upon reproductive success by for example, abrading and reducing flow delivery to incubating eggs. T...

RationaleDorsal white muscle is the standard tissue analysed in fish trophic studies using stable isotope analyses. As muscle is usually collected destructively, fin tissues and scales are often used as non-lethal surrogates; we examined the utility of scales and fin tissue as muscle surrogates.Methods The muscle, fin and scale δ15N and δ13C values...

Invasive species and anthropogenic sources of allochthonous trophic subsidies can have substantial ecological consequences for freshwater ecosystems, including modifying the diet of consumers and altering food web structure. Here, the diet of an omnivorous cyprinid fish, European barbel Barbus barbus, was assessed in relation to the presence of inv...

The utility of using fish scales collected during stock assessment exercises to assess the trophic relationships of riverine fishes using their stable isotopes of d13C and d15N was tested using three riverine fish communities in England (Rivers Great Ouse, Ivel and Goyt). In each river, European barbel Barbus barbus was an important species, with o...