Fish behaviour in response to a midwater trawl footrope in temperate reservoirs

Sajdlová, Zuzana; Draštík, Vladislav; Jůza, Tomáš; Říha, Milan; Frouzová, Jaroslava; Čech, Martin; Vašek, Mojmír; Muška, Milan; Blabolil, Petr; Tušer, Michal; Kratochvíl, Michal; Mrkvička, Tomáš; Balk, Helge; Kubečka, Jan

doi:10.1016/j.fishres.2015.06.025

Cited by 10 publications

(2 citation statements)

References 31 publications

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“…Seining can be applied only in water of moderate depth without large submerged structures (Říha et al ., 2008). Trawling is used to catch fish in open water or close to the bottom (Sajdlová et al ., 2015). Electrofishing can be applied where there is submerged vegetation or other bottom obstacles, but its efficiency is restricted to shallow, relatively clear waters (Blabolil et al ., 2020).…”

Section: Introductionmentioning

confidence: 99%

A comparative study of three fishery methods for sampling the invasive topmouth gudgeon (Pseudorasbora parva) in ponds

Kajgrová

Drozd

Regenda

et al. 2023

Journal of Fish Biology

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Invasive fish threaten ponds' ecological status and their ecosystem services, therefore obtaining a representative sample of fish community composition is fundamental to fishery management, research and nature conservation. Estimates of the size distribution, density and biomass of the topmouth gudgeon (Pseudorasbora parva) model species of invasive fish in three ponds were compared among three sampling methods: electrofishing, fish‐trapping and throw‐netting. The study illustrates that the invasive fish, P. parva, can be detected by all tested fishing methods, yet our results clearly showed that there are pronounced differences among methods in population characteristic estimates. Electrofishing and throw‐netting gave biased information on the size distribution of P. parva. Fish‐trapping and throw‐netting gave reasonable P. parva density and biomass estimates, while electrofishing clearly underestimated it. All tested methods showed a body size increment of P. parva between summer and autumn sampling sessions, yet neither throw‐netting nor electrofishing recorded an increment in its density. Our study showed that fish‐trapping is the most reliable and affordable method to estimate invasive P. parva population characteristics in ponds despite more time‐demanding sampling. The success depends on the mesh size of sampling gear, operator skill and habitat structure. The cost‐effectiveness of the selected methods and the importance of invasive fish monitoring in ponds is discussed. The sampling gear must be considered carefully according to the aim of the monitoring.

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Section: Introductionmentioning

confidence: 99%

A comparative study of three fishery methods for sampling the invasive topmouth gudgeon (Pseudorasbora parva) in ponds

Kajgrová

Drozd

Regenda

et al. 2023

Journal of Fish Biology

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“…The combinations of gear modifications are almost infinite and warrant sea trials to assess their efficiency. Variability in fish behavior among areas, seasons [ 6 , 7 ] and in the net depending on gear configurations such as vertical openings [ 8 , 9 ], prevent straightforward extrapolation of results to other case studies.…”

Section: Introductionmentioning

confidence: 99%

Toward elimination of unwanted catches using a 100 mm T90 extension and codend in demersal mixed fisheries

et al. 2020

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Most European fishing fleets will need to drastically reduce their unwanted catches to comply with new rules of the common fisheries policy. A more practical way to avoid increasing on-board sorting time and issues linked to storage capacity is to prevent unwanted catches in the first place. We assessed the selectivity properties of an experimental fishing gear that combined a 100 mm T90 cylinder with 130 meshes in the extension and a 100 mm T90 codend of 33 meshes (experimental gear) compared to a 100 mm diamond mesh extension and codend (control gear) during commercial trips using twin trawls. Analysis of the relative size composition of catches indicated a significantly higher escapement of small fish of several target species (e.g. Lepidorhombus whiffiagonis, Melanogrammus aeglefinus, Raja spp, and Lophius spp) and non-target species (e.g. Capros aper and Gurnards spp) from the T90 experimental trawl compared to the control trawl (n = 49 hauls), resulting in a significant reduction of unwanted catches of Gadidae, Triglidae, and Caproidae. In contrast, nonnegligible commercial losses of small grade target gadoid species were observed. Mixed general linear models showed that the proportion of ray, haddock and anglerfish retained per length class decreased with increased tow duration. The T90 experimental gear will perform at a commercial level when targeting monkfish, megrim, rays and large haddock, however fishers are not likely to use this gear when targeting smaller-bodied species such as cephalopods, small haddock, whiting (Merlangius merlangus) and hake (Merluccius merluccius), because the gear is likely to allow large numbers to escape. Selectivity studies often focus on a short list of target species; however, catches of non-target species under quota can be problematic for some fisheries. For example, under the implementation of the Landing Obligation catches of boarfish could choke the French whitefish demersal fisheries in the Celtic sea, as France has no national quota for that species. The device tested constitutes an efficient solution to mitigate catches for such non-target schooling fish.

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Spatiotemporal response of pelagic fish aggregations in their spawning grounds of middle Yangtze to the flood process optimized by the Three Gorges Reservoir operation

Tao

Yang

Cai

et al. 2017

Ecological Engineering

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Fish behaviour in response to a midwater trawl footrope in temperate reservoirs

Cited by 10 publications

References 31 publications

A comparative study of three fishery methods for sampling the invasive topmouth gudgeon (Pseudorasbora parva) in ponds

A comparative study of three fishery methods for sampling the invasive topmouth gudgeon (Pseudorasbora parva) in ponds

Toward elimination of unwanted catches using a 100 mm T90 extension and codend in demersal mixed fisheries

Spatiotemporal response of pelagic fish aggregations in their spawning grounds of middle Yangtze to the flood process optimized by the Three Gorges Reservoir operation

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