Mississippi River-floodplain connectivity level mediates fish assemblage dynamics

Journal of Limnology, Journal Year: 2025, Volume and Issue: 84

Published: March 11, 2025

The life histories of many Louisiana fishes are tied to the timing, magnitude, and duration Mississippi River flood pulse. Anthropogenic modifications designed control restrict waters have decoupled Louisiana’s floodplains from seasonal pulse, influencing aquatic food web. Culvert rock weir repair within Richard K. Yancey Wildlife Management Area aims improve water quality maintain appropriate depth for native fishes. In this study we conducted high-resolution imaging sonar (ARIS Explorer 3000) monitoring floodplain fish assemblage across seasons prior hydrologic restoration. Imaging sonars may be used obtain quantitative ecological behavioral information without selectivity biases traditional techniques through recording continuous video-like datasets that not constrained by environmental factors such as turbidity. Our first objective was test hypothesis inundation levels proximity affect abundance size class distribution floodplain-associated assemblage. second characterize species composition function each acoustically-detected using historical fisheries collected Department Fisheries. To do so, employed multi-gear mean standardization technique standardizing catch per unit effort passive active gear types dataset in order produce a non-exhaustive list potentially recorded sonar. demonstrated dependent use habitats mediated level, but distance River. results illustrated trend increased detections all classes during high-water connected-spring summer periods, well disconnected-summer periods immediately following Continued will provide additional data better describe complex dynamic patterns exhibit response pulse restoration efforts.

Language: Английский

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Spotting gar using imaging sonar: The effects of river–floodplain habitat connectivity on a lepisosteid assemblage

Transactions of the American Fisheries Society, Journal Year: 2025, Volume and Issue: unknown

Published: March 27, 2025

ABSTRACT Objective Anthropogenic modifications, such as levee construction and other flood control structures, have decoupled Louisiana’s floodplains from the seasonal pulse, influencing aquatic food web dynamics. Many of fish species rely on timing, magnitude, duration Mississippi River pulse to trigger key aspects their life histories. At Richard K. Yancey Wildlife Management Area, 283 ha floodplain are undergoing weir culvert repair retain water depth improve quality for native Louisiana fishes, with particular focus large nongame species, gars (Lepisosteidae). Methods Beginning in summer 2021, we conducted high-resolution imaging sonar monitoring gar abundance, size-class distribution, habitat use across seasons at four sites through a latitudinal gradient decreasing hydrologic connectivity. We tested hypothesis that degree river–floodplain connectivity, mediated by inundation levels proximity River, affects abundance distribution floodplain. Results Our study demonstrated size-class-dependent habitats was level but not distance River. results suggest remaining pools water, when disconnected main-stem river, likely provide both nursery refuge floodplain-associated gar. Conclusions Continued efforts will additional data better describe complex interactions between fishes relation restoration efforts.

Language: Английский

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European seabass, Dicentrarchus labrax, show no significant response to infrared light

Journal of Fish Biology, Journal Year: 2025, Volume and Issue: unknown

Published: April 1, 2025

Abstract Infrared (IR) light is widely accepted as a non‐intrusive lighting for discreet observation but relevant studies are scarce. The response of European seabass Dicentrarchus labrax (Linnaeus 1758) towards IR was tested during laboratory experiments alternating sequences and dark conditions. Swimming trajectories were extracted from hydroacoustic videos behavioural metrics (e.g. speed, bearings) quantified the D. movement patterns. showed no preference nor deterrence light, supporting use an alternative to visible monitoring unbiased behaviour.

Language: Английский

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Fish as a Deformable Solid: An Innovative Method to Characterize Fish Swimming Behavior on Acoustic Videos

IEEE Access, Journal Year: 2024, Volume and Issue: 12, P. 134486 - 134497

Published: Jan. 1, 2024

Acoustic cameras are increasingly used for continuous, non-intrusive recording and counting of fish passage in natural environments artificial structures such as fishways. However, analysing the large number videos recorded is time consuming. Although automatic reading processes have been developed, poor quality acoustic images, including discontinuity signal a single object, challenging. We developed an innovative method videos. Unlike previous methods, it focuses on swimming locomotion instead morphological properties fish. Each image pre-processed to remove discontinuities restore entire body cluster pixels. The set pixels then tracked retrieve movement, independent displacement fish, using mesh solid deformable model. deformation which subjected between each pair frames (i.e., body) summarised map passage. Testing dataset four species strongly suggested that maps species-dependent. These results must be extended other confirm effectiveness identification characterisation their behaviour camera records.

Language: Английский

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Fish abundance is enhanced within a network of artificial reefs in a large estuary

Frontiers in Marine Science, Journal Year: 2024, Volume and Issue: 11

Published: Nov. 22, 2024

Artificial reefs may be created within estuaries for multiple reasons, including habitat enhancement, oyster production, or recreational fishing. While traditional sampling in this environment is difficult due to complex structures and the high turbidity of estuaries, acoustic imaging sonar provides an effective alternative measure abundance size spectra fish community. We sampled eight artificial Pamlico Sound, North Carolina, that are designated as sanctuaries. At each sanctuary, we 26 boat positions along two transects using ARIS sonar, which included control areas outside sanctuaries over featureless bottom. found mean length were greater sanctuary boundaries, but did not observe any significant differences among substrate types Further, dropped near background levels 25 m edge. Size analysis revealed was higher versus every bin community (5 50 cm). However, greatest 10 30 cm fishes. Our results can coupled with previous research on species composition data more fully understand potential role Sound sanctuaries, estuarine general, serve fishing enhancement.

Language: Английский

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Development and operation of a novel non-invasive opto-acoustic underwater fish observatory in Kiel Bight, Southwestern Baltic Sea

Frontiers in Marine Science, Journal Year: 2024, Volume and Issue: 11

Published: Aug. 20, 2024

This study presents a trilateral test array of new opto-acoustic Underwater Fish Observatories (UFOs) that were operated and tested in Kiel Bight as part the “UFOTriNet” project. While hydroacoustic optical techniques have so far been used individually to observe monitor fish stocks, we present coupled hybrid system consisting an device intended scan near-field subsample spatially larger medium-to-far-field, scanned by acoustical device. The consists two residual light amplifying camera modules able detect classify various marine species at high resolution range max 4 meters area. To compensate for this spatial limitation, component 2D imaging sonar with maximum 50 m, albeit lower resolution. Species affiliation, morphometric characteristics other organisms stereo-optically detected classified nearfield, blended activity medium range, projected onto entire insonified area using algorithm. Through synchronous acquisition multiparametric abiotic biotic data, UFO allows automatic, continuous, non-invasive long-term monitoring their habitats regional hotspots. An 86-day sample revealing abrupt shift from clupeid gelatinous plankton dominated regime summer/autumn 2021 Fjord is demonstrate potential applications.

Language: Английский

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