scholarly journals Determining the safety range of electrical pulses for two benthic invertebrates: brown shrimp (Crangon crangon L.) and ragworm (Alitta virens S.)

2014 ◽  
Vol 72 (3) ◽  
pp. 973-980 ◽  
Author(s):  
Maarten Soetaert ◽  
Koen Chiers ◽  
Luc Duchateau ◽  
Hans Polet ◽  
Bart Verschueren ◽  
...  
Keyword(s):  
Direct Consequence ◽  
Brown Shrimp ◽  
Crangon Crangon ◽  
Electrical Field ◽  
Electrical Field Strength ◽  
Promising Alternative ◽  
Electric Pulses ◽  
Electrical Pulses ◽  
Tail Flip ◽  
Pulse Polarity

Abstract Pulse trawling is currently the most promising alternative for conventional beam trawls targeting sole and shrimp, meeting both the fisher's aspirations and the need for more environmentally friendly fishing techniques. Before electrotrawling can be further developed and implemented on a wider scale, however, more information is needed about the effects of electrical pulses on marine organisms. The organisms used in the present experiments were brown shrimp (Crangon crangon L.) and king ragworm (Alita virens S.) as model species for crustaceans and polychaetes, respectively. These animals were exposed to a homogeneously distributed electrical field with varying values of the following parameters: frequency (5–200 Hz), electrical field strength (150–200 V m−1), pulse polarity, pulse shape, pulse duration (0.25–1 ms), and exposure time (1–5 s). The goal of this study was to determine the range of safe pulses and thereby also to evaluate the effect of the pulses already being used on commercial electrotrawls. Behaviour during and shortly after exposure, 14-d mortality rates, and gross and histological examination were used to evaluate possible effects. The vast majority of shrimp demonstrated a tail flip response when exposed to electric pulses depending on the frequency, whereas ragworm demonstrated a squirming reaction, independent of the frequency. No significant increase in mortality or injuries was encountered for either species within the range of pulse parameters tested. Examination of the hepatopancreas of shrimp exposed to 200 V m−1 revealed a significantly higher severity of an intranuclear baculoform virus infection. These data reveal a lack of irreversible lesions in ragworm and shrimp as a direct consequence of exposure to electric pulses administered in the laboratory. Despite these promising results, other indirect effects cannot be ruled out and further research hence is warranted.

Tail-flip mechanism and size-dependent kinematics of escape swimming in the brown shrimp crangon crangon

1998 ◽  
Vol 201 (11) ◽  
pp. 1771-1784 ◽  
Author(s):  
SA Arnott ◽  
DM Neil ◽  
AD Ansell
Keyword(s):  
High Speed ◽  
Body Position ◽  
Maximum Velocity ◽  
Brown Shrimp ◽  
Centre Of Mass ◽  
Crangon Crangon ◽  
Size Dependent ◽  
Habitat Specialisation ◽  
Tail Flip ◽  
Kinematic Properties

Tail-flip escape swimming by the brown shrimp Crangon crangon has been investigated across a range of body lengths (11-69 mm) using high-speed video analysis. This has revealed several novel aspects of the tail-flip mechanism when compared with that of other decapod crustaceans that have been studied. (i) The pattern of body flexion in C. crangon produces movement of the cephalothorax as well as the abdomen about the centre of mass. (ii) Shrimps form a 'head-fan' with their antennal scales, in addition to the tail-fan formed by their uropods, apparently for generating thrust during tail-flips. (iii) Shrimps typically swim on their side rather than in an upright body position. It is suggested that these features may be interlinked and derive from habitat specialisation. The kinematic properties of tail-flips were found to vary with shrimp size. As shrimp body length increased, the rate of body flexion and re-extension decreased whilst the duration of tail-flips increased. Mean (and maximum) velocity estimates ranged between 0.4 m s-1 (0.7 m s-1) and 1.1 m s-1 (1.8 m s-1) for shrimps of different sizes. The combined effects of escape behaviour and size-dependent variability in tail-flip kinematics will have important implications with regard to predation risk.

Escape trajectories of the brown shrimp crangon crangon, and a theoretical consideration of initial escape angles from predators

1999 ◽  
Vol 202 (2) ◽  
pp. 193-209 ◽  
Author(s):  
S.A. Arnott ◽  
D.M. Neil ◽  
A.D. Ansell
Keyword(s):  
Gadus Morhua ◽  
Longitudinal Axis ◽  
Brown Shrimp ◽  
Crangon Crangon ◽  
Artificial Stimulus ◽  
Initial Stage ◽  
Natural Predator ◽  
Escape Trajectories ◽  
Tail Flip ◽  
Theoretical Analyses

Tail-flip escape trajectories of the brown shrimp Crangon crangon have been investigated in response to a natural predator, the cod Gadus morhua, and an artificial stimulus. Shrimps escaped by rolling to their left or right during the initial tail-flip of a response, and thereafter swam on their side. As a result of the laterally directed first tail-flip, initial escape angles always lay between 75 degrees and 156 degrees with respect to the (pre-escape) longitudinal axis (anterior=0 degrees) of the shrimp. Symmetrical attacks from either head-on or tail-on produced escapes to the shrimp's left or right in equal proportions, although a contralateral bias did occur if the shrimp experienced a looming object from one side before a symmetrical attack was applied. Lateral attacks produced a significantly greater proportion of contralateral responses than ipsilateral ones. Empirical and theoretical analyses indicate that the initial escape direction is influenced by an interaction between the range of first tail-flip escape angles that the shrimp is capable of performing and the risk of being intercepted by a predator during the initial stage of an escape. Thus, the unpredictability (‘protean behaviour’) of the response may be affected by the conditions of the interaction. Subsequent tail-flips of an escape usually directed the response away from the stimulus, but sometimes escapes were instead steered to the side of the stimulus and then behind it. The probability of each type of escape occurring changed with attack direction. The elements of protean behaviour that have been identified in both the initial and subsequent stages of the escape may prevent predators from learning a fixed pattern of response, but a trade-off occurs when escape trajectories infringe upon zones of high capture risk.

scholarly journals Evaluating the efficacy of technical measures: a case study of selection device legislation in the UK Crangon crangon (brown shrimp) fishery

2008 ◽  
Vol 65 (2) ◽  
pp. 267-275 ◽  
Author(s):  
Tom L. Catchpole ◽  
Andrew S. Revill ◽  
James Innes ◽  
Sean Pascoe
Keyword(s):  
Brown Shrimp ◽  
Crangon Crangon ◽  
Shrimp Fishery ◽  
The North ◽  
Ex Post ◽  
Wide Range ◽  
The Uk ◽  
The Impact ◽  
Technical Measures

Abstract Catchpole, T. L., Revill, A. S., Innes, J., and Pascoe, S. 2008. Evaluating the efficacy of technical measures: a case study of selection device legislation in the UK Crangon crangon (brown shrimp) fishery. – ICES Journal of Marine Science, 65: 267–275. Bycatch reduction devices are being introduced into a wide range of fisheries, with shrimp and prawn fisheries particularly targeted owing to the heavy discarding common in these fisheries. Although studies are often undertaken to estimate the impact of a technical measure on the fishery before implementation, rarely have the impacts been assessed ex post. Here, the efficacy of the UK legislation pertaining to the use of sievenets in the North Sea Crangon crangon fishery is assessed. Three impacts were evaluated: on fisher behaviour (social), on the level of bycatch (biological), and on vessel profitability (economic). An apparent high level of compliance by skippers was identified despite a low level of enforcement. The estimated reduction in fleet productivity following the introduction of the legislation was 14%, equalling the mean loss of Crangon landings when using sievenets calculated from catch comparison trawls. Sievenets did reduce the unnecessary capture of unwanted marine organisms, but were least effective at reducing 0-group plaice, which make up the largest component of the bycatch. Clearly the legislation has had an effect in the desired direction, but it does not address sufficiently the bycatch issue in the Crangon fishery.

scholarly journals Predictive framework for codend size selection of brown shrimp (Crangon crangon) in the North Sea beam-trawl fishery

PLoS ONE ◽  
2018 ◽  
Vol 13 (7) ◽  
pp. e0200464 ◽  
Author(s):  
Juan Santos ◽  
Bent Herrmann ◽  
Daniel Stepputtis ◽  
Claudia Günther ◽  
Bente Limmer ◽  
...  
Keyword(s):  
North Sea ◽  
Brown Shrimp ◽  
Beam Trawl ◽  
Crangon Crangon ◽  
Size Selection ◽  
Trawl Fishery ◽  
The North ◽  
Sea Beam ◽  
The North Sea ◽  
Selection Of

Organotins in North Sea brown shrimp (Crangon crangon L.) after implementation of the TBT ban

Chemosphere ◽  
2012 ◽  
Vol 86 (10) ◽  
pp. 979-984 ◽  
Author(s):  
Y. Verhaegen ◽  
E. Monteyne ◽  
T. Neudecker ◽  
I. Tulp ◽  
G. Smagghe ◽  
...  
Keyword(s):  
North Sea ◽  
Brown Shrimp ◽  
Crangon Crangon

scholarly journals Demulsification of Liquid Membrane Emulsion using High Voltage Glass Coated Electrode in Batch System

2017 ◽  
Vol 10 (1) ◽  
Author(s):  
N. Othman ◽  
A. Ahmad ◽  
M. A. Piramali
Keyword(s):  
High Voltage ◽  
Liquid Membrane ◽  
Alternate Current ◽  
Cost Effective ◽  
Electrical Field ◽  
Electrical Field Strength ◽  
Oil Emulsion ◽  
Internal Phase ◽  
The Stability ◽  
Time Required

Demulsification is one of the key processes in emulsion liquid membrane application. This study involved the effect of electrical field on demulsification of water in oil using batch high voltage demulsifier system. This technique widely used because of its advantages of easy manipulation of applied field direction and strength, offers cost–effective separation and minimal environmental impact combined with mechanical simplicity. Influence of various values of frequency (400–1500 Hz) and voltage was studied experimentally using Alternate Current (AC) High Voltage Demulsifier with insulated electrode. The emulsion consists of kerosene as organic phase, sulfuric acid as internal phase and span 80 (3 and 5 w/v %) as a surfactant. The effect of emulsion preparation such as homogenizer speed, internal phase and surfactant concentrations on the stability of water–in–oil emulsion was also investigated. The results showed that the attractive forces between the water droplets under an electrical field increase by raising the applied electrical field strength. Meanwhile, the time required for the emulsion to separate and coalescence under electrical field increased when the stability of emulsion increased.

Sign in / Sign up

Export Citation Format

Share Document