scholarly journals A machine vision system for tracking population behavior of zooplankton in small-scale experiments: a case study on salmon lice (Lepeophtheirus salmonis Krøyer, 1838) copepodite population responses to different light stimuli

Biology Open ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. bio050724
Author(s):  
Bjarne Kvæstad ◽  
Trond Nordtug ◽  
Andreas Hagemann
Keyword(s):  
Machine Vision ◽  
Developmental Stages ◽  
Vision System ◽  
Behavioral Responses ◽  
Experimental System ◽  
Sea Lice ◽  
Small Scale ◽  
Lepeophtheirus Salmonis ◽  
Salmon Lice ◽  
Light Stimuli

ABSTRACTTo achieve efficient and preventive measures against salmon lice (Lepeophtheirus salmonis Krøyer, 1838) infestation, a better understanding of behavioral patterns of the planktonic life stages is key. To investigate light responses in L. salmonis copepodites, a non-intrusive experimental system was designed to measure behavioral responses in a 12.5-l volume using machine vision technology and methodology. The experimental system successfully tracked the collective movement patterns of the sea lice population during exposure to different light stimuli emitted from alternating zones in the system. This system could further be used to study behavioral responses to different physical cues of various developmental stages of sea lice or other zooplankton.

Thermal delousing in anaesthetised small Atlantic salmon (Salmo salar) post-smolts: A case study showing the viability of anaesthesia prior to delousing for improved welfare during treatment for salmon lice

2021 ◽  
Vol 30 (2) ◽  
pp. 117-120
Author(s):  
O Folkedal ◽  
SO Utskot ◽  
J Nilsson
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Experimental Research ◽  
Acute Stress ◽  
Small Scale ◽  
Lepeophtheirus Salmonis ◽  
Salmon Lice ◽  
Sequence Of Events ◽  
Present Case Study

Delousing treatment for salmon sea lice (Lepeophtheirus salmonis) is considered a significant welfare concern in farming of Atlantic salmon ( Salmo salar), where both industry and legislative bodies prompt for better methods. Currently, the most common method is thermal delousing, where fish are crowded, pumped into a vessel and exposed to ∼28–34°C for ∼30 s. Physical collisions occurring as a result of a loss of behavioural control lead to acute stress. Crowding triggers vigorous escape behaviour as salmon respond not only to treatment but also to being channeled to and from the treatment zone. A sequence of events considered to cause mortality and poor welfare. The present case study was motivated by an urgent need for delousing in groups of small salmon post-smolts in experimental research. For this purpose, a simple, small-scale system for thermal delousing was constructed, including anaesthesia to alleviate behavioural responses. The anaesthetised fish showed little behavioural response to thermal treatment, strong appetite within hours, and negligible mortality. The described method is regarded as a welfare-friendly alternative to industrial delousing in smaller fish groups, for example, in experimental research. We would encourage detailed research aimed towards gaining a deeper under-standing of the welfare effects of anaesthesia prior to treatment for delousing.

scholarly journals A review of the biology and genetics of sea lice

2006 ◽  
Vol 63 (7) ◽  
pp. 1304-1316 ◽  
Author(s):  
Karin Boxaspen
Keyword(s):  
Population Structure ◽  
North Atlantic ◽  
Developmental Stages ◽  
Management Strategies ◽  
Molecular Techniques ◽  
Sea Lice ◽  
Lepeophtheirus Salmonis ◽  
New Research ◽  
And Control

Abstract Studies of the biology of sea lice have been conducted from various perspectives for two decades. For Lepeophtheirus spp., most of the published literature has centred on the economically important Lepeophtheirus salmonis, while for Caligus spp., research has focused on a wider range of species. The most numerous species of Caligus in North Atlantic waters, however, is Caligus elongatus, which is also economically important to salmon farming. Since the last review by Pike, A. W., and Wadsworth, S. L. (1999. Sea lice on salmonids: their biology and control. Advances in Parasitology, 44: 234–337.), research on sea lice has developed considerably, including the application of genetic methods. This new research has focused on life history biology, studying developmental stages under different environmental conditions (e.g. temperature and salinity), behaviour, distribution and the dispersal of free-living stages, monitoring practices, population structure, and modelling. The results of this research have informed risk analyses and allowed the refinement of management strategies to reduce sea lice infestations in wild and farmed populations of anadromous salmonids. Molecular techniques have been used to describe population structure and identify differences in genetic characterization of geographically separate populations and population markers. Research has been initiated to understand the parasite–host relationship at a molecular level and to develop a vaccine against sea lice.

Salmon lice infestations on sea trout predicts infestations on migrating salmon post-smolts

2017 ◽  
Vol 74 (9) ◽  
pp. 2354-2363 ◽  
Author(s):  
Knut Wiik Vollset ◽  
Elina Halttunen ◽  
Bengt Finstad ◽  
Ørjan Karlsen ◽  
Pål Arne Bjørn ◽  
...  
Keyword(s):  
Salmo Trutta ◽  
Negative Binomial ◽  
Predictive Ability ◽  
Current Method ◽  
Sea Lice ◽  
Lepeophtheirus Salmonis ◽  
Fish Farms ◽  
Sea Trout ◽  
Salmon Lice ◽  
Management Advice

Abstract Impacts of sea lice (Lepeophtheirus salmonis or Caligus spp.) on wild salmonids is currently one of the most important issues facing management of fish farms in salmon producing countries in the northern hemisphere. Surveillance of sea lice on wild Atlantic salmon (Salmo salar) is often hampered by the ability to catch enough migrating post-smolts. Therefore, sea lice abundance on anadromous trout (Salmo trutta) is often used to infer sea lice abundance on migrating salmon post-smolt. However, the assumption that there is a relationship between the abundance of lice on salmon and trout has never been tested. Here we use a dataset of sea lice on salmon post-smolt and sea trout that have been caught simultaneously in trawl hauls, to evaluate the correlation in abundance of sea lice between the two species using various statistical models. We demonstrate that trout generally has higher abundances of sea lice than salmon. Average lice per gram fish on sea trout (log transformed) predicted the abundance of lice on salmon best. Negative binomial models of lice counts were preferable to using trout lice counts as direct estimates of salmon lice abundance, and they had better predictive ability than logit models of high (vs. low) lice counts. Including the size of the salmon increased the predictive ability of the model, but these data are not generally available. The effect of salmon weight may have been a direct effect of body size, or an indirect effect of time spent in marine waters. Finally, we predict lower salmon lice counts on migrating salmon with our selected binomial model than with the current method of using trout lice counts as a direct estimator on salmon lice counts, and demonstrate that management advice would change considerably depending on the chosen method.

Ontogenetic changes in visual sensitivity of the parasitic salmon louse Lepeophtheirus salmonis

2000 ◽  
Vol 203 (11) ◽  
pp. 1649-1657 ◽  
Author(s):  
I. Novales Flamarique ◽  
H.I. Browman ◽  
M. Belanger ◽  
K. Boxaspen
Keyword(s):  
Spectral Range ◽  
Developmental Stages ◽  
Polarized Light ◽  
Bright Light ◽  
Visual Sensitivity ◽  
Spectral Irradiance ◽  
Lepeophtheirus Salmonis ◽  
Ontogenetic Changes ◽  
Salmon Louse ◽  
Salmon Lice

The salmon louse, Lepeophtheirus salmonis, is an ectoparasitic copepod of salmonid fishes whose life cycle involves two broadly defined, free-living larval stages, the nauplius and the copepodid. After settling on a host, the copepodid goes through various transformations to become a mobile adult. We recorded swimming responses of free-swimming salmon lice at the naupliar, copepodid and adult stages to the onset (ON) and offset (OFF) of lights of varying spectral irradiance and polarization. Nauplii showed a prominent swim-up OFF response across the spectrum 352–652 nm, but no ON response. Copepodids exhibited a swim-up ON response and a passive (sinking) OFF response across the same spectral range. Adults showed active swim-up responses to both ON and OFF stimuli, although the OFF response was proportionately stronger. The spectral range of the adult ON and OFF responses was the same as that of the copepodids and slightly greater than that of the nauplii, which did not exhibit responses at 652 nm. The absolute sensitivity of copepodids under white light (approx. 10(−13) photons m(2) s(1)) was higher than that of nauplii (approx. 10(−17) photons(−1) m(2)s, OFF response) and that of adult female lice (approx. 10(−14) photons(−1)m(2)s). This suggests that the naupliar visual system is best suited for detection of shadows (e.g. the host) under a bright light field (daylight hours), while copepodids and adults may be more specialized for host detection at crepuscular periods and during the night, when light levels are low. None of the developmental stages responded to the rotation of the plane of polarized light or exhibited any difference in directed response when polarized light was used in place of diffuse light.

Machine Vision Support System for Monitoring Water Quality in a Small Scale Tiger Prawn Aquaculture

2016 ◽  
Vol 20 (1) ◽  
pp. 111-116 ◽  
Author(s):  
Reggie C. Gustilo ◽  
◽  
Elmer P. Dadios ◽  
Keyword(s):  
Water Quality ◽  
Machine Vision ◽  
Vision System ◽  
Quality Parameter ◽  
Water Quality Parameter ◽  
Small Scale ◽  
Quality Level ◽  
Machine Vision System ◽  
Safe Level ◽  
Tiger Prawn

A fuzzy-based machine vision system was designed to support an industrial sensor based small scale tiger prawn aquaculture system. This system is based on the behavioral movements of tiger prawns as they are subjected to different stress levels such as unsafe values of dissolved oxygen, temperature, salinity and ph. Each parameter is carefully adjusted to trigger a change in the normal behavior or movement of tiger prawns. The change in the behavior of the tiger prawn, as seen by the machine vision system, may serve as a level detection or an alarm system that will aid the sensor based system in terms of monitoring the water quality of the aquaculture environment. This machine vision system may be used to trigger the actuators needed to correct the dangerous water quality parameter back to its safe level. This research is done in real time using two basic web cameras to support industry grade sensors in maintaining the safe water quality level for this small scale habitat.

Assessment of stable isotopic signatures as a means to track the exchange of sea lice (Lepeophtheirus salmonis) between host fish populations

2011 ◽  
Vol 68 (7) ◽  
pp. 1243-1251 ◽  
Author(s):  
Susan Dean ◽  
Claudio DiBacco ◽  
Robert Scott McKinley
Keyword(s):  
First Generation ◽  
Developmental Stages ◽  
Fish Population ◽  
Fish Populations ◽  
Sea Lice ◽  
Lepeophtheirus Salmonis ◽  
Host Fish ◽  
Isotopic Signatures ◽  
Stable Isotopic ◽  
Over Time

The viability of stable isotopic carbon (δ13C) and nitrogen (δ15N) signatures to track the exchange of sea lice, Lepeophtheirus salmonis , between hosts was tested. It was predicted that nonfeeding sea lice would experience lowered δ13C signatures and enriched δ15N signatures owing, at least in part, to moulting during development. It was also predicted that newly settled parasitic first generation sea lice (late stage copepodids) would retain isotopic signatures indistinguishable from their natal host fish population. During this laboratory study, δ13C signatures of nonfeeding sea lice developmental stages declined over time, while the δ13C signature of chalimus III sea lice was not significantly different from fin and gill signatures of their natal hosts, thus providing an isotopic link to their natal host fish population. In contrast, δ15N analysis did not show promise as a tracer in this study, as host fish populations did not display distinct δ15N signatures. These results suggest that δ13C signatures may be applied to identify sources of sea lice epizootics and potentially quantify the exchange of sea lice between cultured and wild salmon populations.

scholarly journals Sea lice prevention strategies affect cleaner fish delousing efficacy in commercial Atlantic salmon sea cages

2020 ◽  
Vol 12 ◽  
pp. 67-80 ◽  
Author(s):  
K Gentry ◽  
S Bui ◽  
F Oppedal ◽  
T Dempster
Keyword(s):  
Atlantic Salmon ◽  
Sea Lice ◽  
Small Scale ◽  
Faroe Islands ◽  
Biological Control Agents ◽  
Prevention Strategies ◽  
Cleaner Fish ◽  
Salmon Lice ◽  
Multiple Structures ◽  
Production Period

Over the last 2 decades, cleaner fishes have been employed to remove external sea lice parasites from Atlantic salmon Salmo salar in sea cages. Norway, Scotland, Ireland, and the Faroe Islands combined now use ~60 million cleaner fish per year. While small-scale experiments demonstrate the efficacy of cleaner fishes, industrial-scale sea cages have multiple structures and conditions that create different environments, which may impact cleaner fish efficacy and welfare. Here, in commercial sea cages, we investigated if 4 different anti-lice strategies impacted the delousing efficacy, physical condition, and behaviour of cleaner fish (corkwing wrasse Symphodus melops). The strategies tested were: (1) cleaner fishes only; (2) cleaner fishes and functional feed; (3) cleaner fishes, functional feed, and deep lights and feeding; and (4) cleaner fishes, functional feed, deep lights and feeding, and lice skirts. Corkwing wrasse were sampled from 3 cage-level replicates of each anti-lice strategy 3 times over 2 mo. Lice levels on salmon were recorded every 3 to 4 wk. Only 11% of corkwing wrasse had salmon lice in their gut, with individual wrasse having up to 72 lice in their stomach. Wrasse in cages encircled by lice skirts consumed one-ninth as many lice as those in other anti-lice treatments and had less overall impact on the number of lice per salmon. Fin, skin, mouth and eye condition, K factor, and observed cleaning behaviours of corkwing wrasse were similar across all anti-lice strategies. Our results demonstrate that different in-cage anti-lice strategies altered the magnitude of lice consumption in corkwing wrasse at this site and for this production period. Moreover, while a small proportion of corkwing wrasse appear to target lice as prey, most individual corkwing wrasse were ineffective biological control agents in a full-scale farm setting.

Multifunctional stereoscopic machine vision system with multiple 3D outputs

2020 ◽  
Keyword(s):  
Machine Vision ◽  
International Symposium ◽  
Fast Track ◽  
Vision System ◽  
Machine Vision System ◽  
Stereoscopic Displays ◽  
Electronic Imaging

Fast track article for IS&T International Symposium on Electronic Imaging 2020: Stereoscopic Displays and Applications proceedings.

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