Flow, refuge, and invasion: common carp (Cyprinus carpio) behaviour under simulated hydropeaking conditions

Freshwater habitat invaders: Impacts on artificial flow refuge use by native fish under pulsed flows

Swimming, grazing and social behaviour of rohu Labeo rohita (Hamilton) and common carp Cyprinus carpio (L.) in tanks under fed and non-fed conditions

Invasive fish species are a major driver of freshwater ecosystem degradation across the globe. This urgent problem is particularly tough to manage in dammed rivers, where the reestablishment of longitudinal connectivity for native fish is achieved through the placement of fish passage devices, which can open a new corridor for the dispersal of these taxa to previously inaccessible habitats. In an attempt to solve this dilemma and prevent their dispersal, an experimental study was conducted in a full-scale Vertical Slot Fishway (VSF) to assess the passage performance of the common carp (Cyprinus carpio), an invasive non-native cyprinid species widespread in the Iberian Peninsula. With this objective, two configurations were designed and tested, where the main hydraulic parameters that govern fishway operation (discharge, flow velocity, turbulence and slope) were adjusted to exceed design guidelines set for cyprinid species. Common carp passage trials were conducted in configuration VSFh1 and VSFh2 (N=8 in each configuration), varying in water depth - 0.55m and 0.80m, respectively, and both were set up with a high slope (15,2 %), head drop (Δh=0.28m) and volumetric dissipation power higher than literature recommendations (Pv>150 Wm-3). Fish movements were assessed in terms of motivation, transit time and ascent analysis using a time-to-event approach. The hydrodynamic scenarios experienced by fish during the trials were investigated with a computational fluid dynamic (CFD) model. Common carp passage results were compared with the performance of a native cyprinid species, namely the Iberian barbel (Luciobarbus bocagei), and pointed to selective fishway configurations, which hindered invasive fish passage movements, but favored the native species. In both configurations, common carp revealed a lower motivation with a significantly lower probability of performing passage attempts compared to the Iberian barbel. Regarding the ascent movements, none of the common carp tested managed to pass VSFh1 while in VSFh2 only one individual managed to ascend (of 3 that attempted - 33 %). Comparatively, the Iberian barbel managed to ascend both configurations, with VSFh1 showing a higher number (17) of these movements (of 17 that attempted to pass - 100 %). Overall, these promising results point to a selective passage under the tested configurations, specifically configuration VSFh1 that can assist managers in reestablishing river connectivity while deterring the spread of non-native invasive fish. Nonetheless, further studies and field validation are required to reinforce the present findings.

The artificial pulsed flows occurring downstream of hydropower plants due to electricity demand, i.e. hydropeaking, affect habitat selection by fish. This effect is particularly unknown for cyprinids, which are the most representative freshwater fish family in European rivers. This study aimed to evaluate the utility of two types of flow-refuge by Iberian barbel (Luciobarbus bocagei) at an indoor flume (6.5m x 0.7m x 0.8m) as a potential solution to mitigate the effects of pulsed flows associated to hydropower production. Based on previous comprehensive research conducted on cyprinids and with the results of this study, the best type of flow-refuge was selected, up-scaled and implemented downstream of small hydropower plants. Two different approach angles with the flume wall - 45⁰ and 70⁰ - were tested to assess the effectiveness of the created hydraulic conditions on attracting fish to the flow-refuge. For each type we tested a base flow event (7 l.s-1), simulating river natural conditions, and a peak flow event (60 l.s-1), simulating pulsed flows. For each setting, two flow-refuges (downstream and upstream) were installed in the flume and tested with a school of five Iberian barbels. The utility of the flow-refuges was assessed by the frequency and time of use by fish at two distinct flow-refuge locations i.e., downstream (area between the flume and the adjacent flow-refuge walls), and inside (the effective covered area of the flow-refuge). Blood glucose and lactate levels were quantified to identify potential physiological adjustments associated with the pulsed flows and the flow-refuge type. Preliminary results indicate that fish behavior differs according to flow event and the type of flow-refuge. The frequency of a single fish using the flow-refuge was higher in the 45⁰ refuge during pulsed flows than in the 70⁰. Overall, the average time spent inside the flow-refuges was higher during pulsed flows for both types and higher in the 45⁰ refuge.  After the 60 l.s-1 events, the blood glucose and lactate levels were higher than in the 7 l.s-1 events. In addition, lactate levels for the 45⁰ flow-refuge during the 60 l.s-1 events, were the highest when compared to 7 l.s-1 events. These results may be explained by the higher velocities created in the presence of the 45⁰ flow-refuge, shown by ADV results, that favoured individual use and rheotactic behaviour, setting off physiological adjustments, increasing residency time and the efficiency to use the flow-refuge.

This study was aimed to estimate the selectivity properties of multifilament trammel and gillnets for common carp ( Cyprinus carpio L., 1758) in Marmara Lake in Manisa, Turkey. Trammel and gillnets of 4, 6, 8, and 10 cm stretched mesh size and 210 d/2 no twine thickness were tested in the Marmara Lake. In addition, selectivity parameter of 11, 12, 13 and 14 cm mesh size of trammel and gillnets were modelled. SELECT method was used to estimate the selectivity parameters. Experiments were carried out monthly in the three different stations identified eastern, middle and western areas which represent longitudinal length of the lake. A total of 36 trials were conducted both nets. A total of 119 common carps were caught ranges between 11.3 - 49.0 cm total lengths. According to the Bi- normal model, which gave the lowest deviance for both trammel and gillnets, selectivity curves were estimated for 4, 6, 8, 10, 11, 12, 13 and 14 cm stretched mesh size modelled lengths as 12.98, 19.47, 25.96, 32.45, 35.70, 38.94, 42.19 and 45.43 cm for trammel nets, 12.40, 18.60, 24.80, 31.00, 34.10, 37.20, 40.30 and 43.40 cm for gillnets, respectively. When considering minimum landing size (40 cm total length), it is recommended that both nets under 13 cm mesh size should be prohibited for common carp fishery in the Lake Marmara. Keywords: Trammel net, gillnets, common carp Cyprinus carpio, size selectivity, Lake Marmara

The effects of silver nanoparticles (Ag-NPs) sublethal concentrations on common carp (Cyprinus carpio): Bioaccumulation, hematology, serum biochemistry and immunology, antioxidant enzymes, and skin mucosal responses.

Ecosystems worldwide are increasingly being invaded by multiple species, and the rate of biological invasion is accelerating, leading to more interactions among invasive species. One such interaction that has received little attention is the phenomenon of ‘serial replacement’ or ‘over-invasion’, where an established invasive species is supplanted by a second invasive species. Understanding this interaction is important as controlling the second species could inadvertently lead to an increase in the abundance of the first species. We used a hierarchical state-space model to analyse changes in annual abundances (commercial catch-per-unit-effort) of three invasive fish species, tench (Tinca tinca), common carp (Cyprinus carpio) and redfin perch (Perca fluviatilis), in the Murray-Darling River system (MDRS), Australia between 1954–2002. Tench were present at low abundances until the mid-1970 s, before declining to the point of no commercial catch post-1989. This rapid decline coincided with a significant increase in carp abundance, suggesting that carp may have driven the tench decline through habitat modification (particularly the destruction of aquatic plants), consistent with findings from European studies that show the disappearance of tench from ponds with intensive carp farming. Redfin perch populations, were inferred to be much less impacted by the invading carp population. While carp were present in the MDRS for the duration of the study, the rapid increase in carp abundance in the early 1970 s coincided with the introduction of a specific genetic lineage—the “Boolarra strain”. Our analysis provides compelling evidence of serial replacement of long-established tench by invading common carp triggered by the introduction of a novel carp strain.

Assessing impacts of a notorious invader (common carp Cyprinus carpio) on Australia's aquatic ecosystems: Coupling abundance-impact relationships with a spatial biomass model

The present study was conducted on two species of cyprinid fish: Common Carp (Cyprinus carpio) and grass Carp (Ctenopharyngodon idella). The study includes the effect of increasing salinity on survival rate, oxygen consumption, glucose and total protein levels in blood plasma, energy usage, food consumption and growth rate. Common carp show more resistance to increasing salinity with 90% survival rate in 15 g/l salinity. While grass carp did not survive increasing in salinity more than 5 g/L. Increasing salinity was accompanied with decreasing total protein in blood plasma, increasing blood glucose, increasing oxygen consumption rate and increasing energy usage. Food intake was also decrease with increasing salinity which results in decreasing growth rate for both fish species. This study showed that salt stress negatively affect food intake, energy usage and decrease growth rate.

The potential of lateral refuges for Iberian barbel under simulated hydropeaking conditions

Diel rhythmicity of grazing, swimming, resting andsocial interactions of rohu (Labeorohita)(weight66.5^68.3g) and common carp (Cyprinus carpio)(79.9^82.0g) were observed in1m 2 simulated ponds usingvideoimages. Fishbehaviour was monitored duringafull24-hperiod,startingat08:00hourswitha15-minrecording, whichwas repeated every 3h. Rohu spentmoretimegrazingduringthedaythanatnight.Graz-ingactivity peakedat thebeginningandat the endofthe day. Grazing and resting of rohu were negativelycorrelated.Commoncarpgrazeddayandnight,show-ing no distinctgrazing peak. Considering thegrazingtime of rohu and common carp, a feeding schedulewithtwofeedingtimesat07:30and16:30hoursmightbeappropriateforbetterfoodintakeandconversioninrohu^commoncarppolyculturesystem.Keywords: swimming, grazing, behaviour, rohu,commoncarpIntroductionTogether, rohu Labeo rohita (Hamilton) and commoncarp Cyprinus carpio (L.) contribute 26% (rohu 11%,commoncarp15%)ofthetotalworldfreshwateraqua-culture production outside China (FAO 2005). Nowa-days, rohu^common carp polyculture is being widelypracticed in South Asia. Rohu is a highlyappreciatedconsumption ¢sh, fetching good market prices (Dey,Paraguas, Bhatta, Alam, Weimin, Piumsombun,Koeshandrajana,DungSRahman,Wahab& Verdegem 2007), while common carp is gainingquick popularity as a bottom feeder in South Asiabecause it has a faster growth rate than the nativebottom feeder mrigal Cirrhinus cirrhosus (Bloch)(Milstein,WahabRRahman2006).The eiects of addition of arti¢cial feed and diier-ent densities of common carp on natural food avail-ability, food intake and growth and production inrohu ponds were studied (Rahman, Verdegem,Nagelkerke,Wahab, Milstein & Verreth 2006). It wasobservedthatbotharti¢cialandnaturalfoodsareim-portant for the growth of rohu and common carp.Thepondstudyshowedsynergisticeiectsonnaturalfood availability in rohu^common carp polyculture.The question was raised as to whether the observedsynergism was mainly caused by increased naturalfoodavailabilityorbyachange in feedingbehaviour.Behaviouralstudiesinpondsaredi⁄cultduetohighturbidityand, consequently, low visibility.Therefore,to be able to observe the feeding behaviour, pondtreatments were simulated in aquaria.The eiects ofarti¢cial feed applicationand diierent stocking den-sities of common carp (0, 1 and 2tank

Innate immune response against an oomycete pathogen Aphanomyces invadans in common carp (Cyprinus carpio), a fish resistant to epizootic ulcerative syndrome

Regulation of glucose and lipid metabolism by insulin and glucagon in vivo and in vitro in common carp Cyprinus carpio L.

Molecular characterizations, immune modulation, and antibacterial activity of interleukin-17A/F1a and interleukin-17A/F1b in common carp Cyprinus carpio

Growth performance and immune status in common carp Cyprinus carpio as affected by plant oil-based diets complemented with β-glucan