Catching Performance Research Articles

Trade-off between drag and catch performance when designing zooplankton trawls

The aquaculture sector is in pursuit of sustainable and cost-effective raw materials for feed, and the copepod Calanus finmarchicus is a marine zooplankton species of commercial interest because of its high abundance in northern areas. These copepods have the potential to meet the demand for vast quantities of marine raw materials. However, the lack of an energy- and catch-efficient trawl technology has limited the development of this fishery. Therefore, this study investigated the effect of two central trawl net design parameters mesh size and taper angle to identify which values that provide optimal trade-off balance between gear drag and catch efficiency. We conducted flume tank experiments using a series of plankton nets varying in mesh size (250–1000 μm), solidity ratio (0.54–0.76), and taper angle (5°– 30°) to acquire data on gear drag. The same nets were then used in fishing trials to obtain data on their catch performance. This study shows that zooplankton nets with a mesh size of approximately 500 μm and a low taper angle of about 5° provided the best trade-off between drag and catch performance.

Semi-pelagic self-adjusting otter boards: effects on the catching performance of a demersal trawl

In this study, we investigate whether replacing conventional seabed-contacting otter boards with semi-pelagic self-adjusting otter (SAO) boards, which have the ability to maintain a given height above the seabed, affects the catch efficiency of a demersal fish trawl. Experimental fishing trials, using the alternate haul method, were conducted in the Kattegat and Skagerrak with three otter board configurations using conventional seabed-contacting otter boards; the SAO set to maintain a target height over the seabed of 1 m; and the SAO set to maintain a target height of 5 m. Replacing conventional otter boards with SAO resulted in a loss of catch efficiency for haddock ( Melanogrammus aeglefinus), whiting ( Merlangius merlangus), and plaice ( Hippoglossoides platessoides), while no significant difference was found for cod ( Gadus morhua), common dab ( Limanda limanda), and lemon sole ( Microstomus kitt). When comparing the SAO-1 m and SAO-5 m, it was observed that SAO-5 m resulted in a loss of catch efficiency for haddock and plaice, a minimal reduction for cod, and no significant difference for whiting, common dab, and lemon sole.

Sunglass tint does not impact the indoor catching performance of cricket fielders.

Sunglasses are worn by outdoor athletes such as cricketers for many reasons, including comfort and glare reduction, which may help to improve vision. Anecdotally they are purported to have performance-enhancing benefits, but there is a lack of evidence for this. Further, it appears that fielders are the only position in cricket who wear sunglasses. Therefore, this study aimed to compare the catching performance of fielders when wearing three different colour sunglasses tints during an indoor, laboratory-based experiment. Twenty-one male cricketers currently playing for a university or amateur provincial teams in Makhanda, South Africa, who were non-habitual sunglass wearers, were recruited for this study. An optometrist administered pre-screening tests. Players had four testing sessions during which they wore a different colour tint at each session indoors (clear, blue, G30 (rose), and red). Players were required to catch 18 balls projected from a bowling machine. The number of balls caught, as well as the quality of the catch, was recorded. At the final session, they were asked which tint they thought was best. Pre-screening tests showed that the red lens was best for contrast sensitivity and stereopsis. During data collection, sunglass tint did not affect catching performance. The players perceived the red lens as the worst and the G30 as the best. It can be concluded that catching performance indoors is not affected by tint colour.

Using hydrodynamics to modify fishing performance of a demersal fishing gear

This study demonstrates how hydrodynamics can be used to influence the fishing performance of towed demersal fishing gears. Sea trials are performed in the sea star fishery to show how modifications to the gear design alter the hydrodynamics of the turbulent wake and consequently affect the catching performance of trawl gears. The trials are performed on cockle and mussel beds and the effect of the gap between the towing beam and the seabed, and the effect of the size of the beam are investigated. Two different beam sizes are utilized where a large beam reduces the mussel bycatch and increases the sea star catch rate if positioned a suitable distance over the seabed. The catch rate is independent of the distance between the beam and the fishing line within the investigated interval.

Effect of artificial lights on catch efficiency and capture patterns in Asian paddle crab (Charybdis japonica) gillnet fishery

The gillnet fishery targeting Asian paddle crab (Charybdis japonica) is an important commercial fishery in the Yellow Sea of China. However, low catch rates represent a challenge, and solutions for improving the catch efficiency are crucial for economical sustainability in this fishery. Therefore, we tested whether the use of artificial fishing lights could improve gillnet catch performance. Specifically, we investigated the effect of using different colored light-emitting diodes (LED) on gillnet catch efficiency and capture patterns. The results showed that attaching white and blue LED lights to gillnets did not significantly affect the catch efficiency of C. japonica, compared to the conventional gillnets without LED lights attached. However, green LED lights significantly improved catch efficiency of legal-sized C. japonica by an average of 57%. Furthermore, a significant reduction (∼35%) in the catch efficiency of undersized crabs was observed for gillnets equipped with red LEDs; however, without any significant effect on catches of legal-sized C. japonica. Moreover, significant differences were observed for the catch composition of species between gillnets with and without LED lights. The findings of this study can provide insight into potential improvements of the fishing strategies in the C. japonica gillnet fishery.

Effect of gillnet twine thickness on capture pattern and efficiency in the Northeast-Arctic cod (Gadus morhua) fishery

Gillnets are among the most common fishing gears worldwide. They are often made of thin twine, which is prone to wear and tear, limiting the lifespan of the gillnet. This increases gillnet turnover, and consequently increased risk of gear discarding, gear loss, ghost fishing and marine pollution. This might be mitigated by increasing twine thickness, and thereby breaking strength. However, the tolerable increase in thickness for gillnet durability without compromising the catch efficiency is unknown. Therefore, this study conducted gillnet fishing trials under commercial conditions in the Northeast-Arctic cod gillnet fishery analysing and comparing ways of capture and efficiency between gillnets with two different twine thicknesses for two different mesh sizes. The results demonstrated that a 30 % increase in breaking strength and twine stiffness did not affect catch performance. Therefore, thicker gillnet twine can potentially reduce marine litter by plastic debris from damaged and lost gears without compromising catch performance.

No effects of ground-gear diameter on the performance of a south-eastern Australian fish trawl

As part of attempts at improving the selectivity of south-eastern Australian fish trawls, the effects of ground-gear disc diameter on trawl engineering and catching performances were investigated. Three conventional disc diameters (100 mm or 4 in., 178 mm or 7 in. and 254 mm or 10 in.) at the centre third of the ground gear were alternated during 12 days of conventional fishing. There were no significant effects of ground-gear configuration on otter-board spread or the headline height of the trawl. Rather, significant influences were limited to depth affecting positive and negative relationships with otter-board spread and headline height, and speed over the ground evoking a positive effect on otter-board spread. Catches of four retained species (bigeye ocean perch, Helicolenus barathri, pink ling, Genypterus blacodes, ocean leather jacket, Nelusetta ayraud, and tiger flathead, Platycephalus richardsoni) and two discards (smooth whiptail, Malacocephalus laevis and falseband whiptail, Coelorinchus maurofasciatus) and the sizes of three of these species, were not significantly different among ground gears. The results imply minimal benefit in varying conventional ground-gear configurations for reducing unwanted catches.

Every animal matters! Evaluating the selectivity of a Mediterranean bottom trawl fishery from a species community perspective.

Bottom trawl fisheries often catch several species simultaneously. However, most studies addressing the catch performance and selectivity of a specific trawl focus on a few commercially important or most vulnerable species requiring management measures. By contrast, the present study considers the multispecies nature of Mediterranean bottom trawl fisheries through a holistic approach that accounts for the full species community in the catches. Specifically, we evaluated and compared the catch performance of the two codends allowed for this fishery, made of 40 mm square (SM40) and 50 mm diamond (DM50) meshes. Results showed that 50 and 80% of the catch in weight and count numbers, respectively, consisted of species without commercial value, demonstrating that large proportions of the catch are not considered when using the existing approach to evaluate the ecological impact of the fishing activity. Significant differences in catch profiles between the two codends were observed, especially for two commercial flatfish species, Arnoglossus laterna and Citharus linguatula, with larger contributions in the SM40. Further, the SM40 codend had a significantly higher retention, compared to DM50 codend, for specific sizes of Merluccius merluccius and Mullus barbatus. The outcomes of the study can be useful for the Mediterranean bottom trawl fisheries management.

Impact of ground gear design on catch efficiency in demersal trawl fishery

The choice of ground gear design in demersal trawls can significantly affect both catch composition and efficiency. The preference for a specific design depends on the fishing ground. In the North-Eastern Mediterranean, two types of ground gears, Single Line and Double Line are commonly used. Therefore, this study compared the catch performance for trawls using these ground gears during research trials in the Mersin Bay multi-species demersal trawl fishery. Results showed a significant reduction in catch efficiency for common sole (Solea solea) and lizardfish (Saurida lessepsianus) with more juveniles and target-sized individuals being released by the Double Line trawl compared to the Single Line trawl. Contrary, no difference was obtained for red mullet (Mullus barbatus) between the two gears. The present study demonstrates that ground gear design can affect species and size composition in demersal trawl fisheries. Therefore, ground gear design should be considered in the fisheries regulations as well as for demersal sampling trawl configurations.

Application of Light-Emitting Diode Lights to Bluefin Sea Robin (Chelidonichthys spinosus) Catch in Pot Fishery in the South Sea, Korea

The bluefin sea robin (Chelidonichthys spinosus), hereafter BSR, is one of the most important fish species in the South Sea of Korea. The production value of BSR in 2020 was USD 4,733,057. The production volume in Korea has shown an annual mean increase of 8.9% since 2010, but the efficiency of the fishing gear decreased due to excessive use. This has led to a decrease in the profitability of fishery operators, and as compensation, the use of fishing gear has further increased through competitive operations. Alternative measures for improving catch performance and reducing the use of fishing gear are needed. As one such measure, LED (Light-Emitting Diode) lights were attached to the pot, and the effects were determined. The field experiment results showed that the catch of BSR was higher for the experimental groups (n = 10–273) using fishing gear with LED lights (red, green, blue, and white) than for the control group (n = 2) (Kruskal–Wallis test, p < 0.05). Among the experimental groups, the pot with green light achieved the largest catch (n = 273). The use of LED lights was found to enhance the catch efficiency of pot fishing gear for BSR.

Management Strategy Evaluation for the Common Spiny Lobster, Palinurus elephas (Fabricius, 1787), Stock in Tunisia

The common spiny lobster, Palinurus elephas (Fabricius, 1787), fishery in Tunisia has been overexploited. This species is currently managed by temporal closures, minimum legal sizes of landings, and the prohibition of catching berried females. This study aims to develop management procedures (MPs) based on the surplus production model to set total allowable catch (TAC) as a management action for the common spiny lobster. Ten MPs ranging from conservative to more relaxed management procedures were evaluated within a management strategy evaluation (MSE) framework. Several scenarios of the operating model were considered to account for uncertainties. Five performance measures were used to evaluate MPs to identify the management strategies that can achieve the prespecified management objective of recovering the stock size as a priority and ensuring high and stable catches. The results of the MSE showed that the conservative management strategies with the highest control points performed well in terms of management objectives with a probability of biomass exceeding the reference point of higher than 90 % but yielded in the lowest catches. On the other hand, relaxed threshold-based management strategies failed in achieving management objectives with 20 % probability of being below the limit reference point. These MSE results also highlighted the trade-off between conservation and catch performance objectives and showed that some moderate management strategies balanced these objectives efficiently.

Testing trapping protocols for detecting the Citrus Longhorn Beetle, Anoplophora chinensis (Coleoptera: Cerambycidae)

AbstractCitrus Longhorn Beetle (CLB), Anoplophora chinensis (Coleoptera: Cerambycidae) is a highly polyphagous species native to eastern and south‐eastern Asia. In 2000, an outbreak of A. chinensis was detected in Lombardy Region (Italy). In 2017, an extensive trapping experiment was conducted at three infested sites in order to evaluate the effectiveness of three variables: trap model (Econex soft cross‐vane trap, Witasek cross‐vane trap and Witasek multi‐funnel trap), trap position (on a wooden pole in an open space or in the canopy of a host tree) and type of lure (ChemTica, Synergy and Glabriwit pheromones). Each combination of variables was replicated five times at each site, giving a total of 270 traps. At the end of the study, 162 adults had been caught, with catches gradually increasing during the month of June to peak in early July. The two cross‐vane traps outperformed the multi‐funnel traps and the Econex traps captured more females than the Witasek traps, probably due to the structure of the collecting funnel. The three lures had similar catch performance, although the best combination was the Econex trap with Synergy blend, due to the remarkable variability in catches observed with Glabriwit blend. Finally, traps set in the tree canopy outperformed traps set on wooden poles. In conclusion, the best protocol was the use of Econex cross‐vane traps baited with Synergy blend and deployed on the canopy of the host trees.

Examining engineering performance of midwater trawl with different horizontal spread ratio, floatage, and weight parameters: A case study of model net for Antarctic krill fisheries

It is necessary to investigate the effectiveness of the midwater trawl in reducing fuel consumption and increasing catch performance for the development and improvement of the Antarctic krill fisheries. A 1/35 scale trawl model for Antarctic krill fisheries was designed based on modified Tauti's law and tested in a flume tank, and the effects of flow velocity, horizontal spread ratio, sinking force, and the ratio of buoyancy to fishing line weight on its engineering performance were analyzed in this study. The results indicated that the lower flow velocity and the ratio of buoyancy to fishing line weight conducted to the greater hydrodynamic forces and geometrical performances. The higher horizontal spread ratio and sinking force were found to have exhibited the greater drag force, net mouth opening, wing-end spread, bridle angle, net mouth area, swept area, and volume covered by trawl net. It was revealed that the engineering performance of the midwater trawl (minimal ratio between drag and swept area) was efficient when the horizontal spread ratio was at 0.55 (corresponding to the trawl horizontal opening of 64.65 m in full-scale), the sinking force was at 97.96 g (600 kg of full-scale), and the ratio of buoyancy to fishing line weight was at 4.2 and 2.6 compared to those actually used during Antarctic krill fishing. In addition, the study demonstrated that the modification of the horizontal spread ratio, sinking force, and the ratio of buoyancy to fishing line weight can be one alternative to improve the geometrical shape performance of the midwater trawl net that could improve catchability of the trawl net.

Catching performance and catching efficiency of siliconized baits in hand line fishery

The present study investigated the catching performance and catching efficiency of natural mud shrimp (alive) (Upogebia pusilla), siliconized mud shrimp and siliconized pellet in handline fishing. The trials were performed in Kıyıkışlacık Village of Muğla province. The main body of the handline is Ø 0.50 mm, leader and snood are Ø 0.27-0.30 mm, the snood length and distance are 10 cm and 20 cm, respectively. Each handline has 3 hooks and the hook type is 4 no straight. Catches from natural mud shrimp, siliconized shrimp and siliconized pellet bait retained separately, sorted by species and weighed as. 0.01 g sensitivity and measured as the total length. Totally 590 individuals from 30 different species in total were caught including; 28 bony fish (93.33%), and 2 cephalopods (0.66%). While natural mud shrimp captured the 50.7% of fish, 44.7% and 4.6% were caught with siliconized mud shrimp and siliconized pellet, respectively. CPUE values of natural mud shrimp, siliconized shrimp and silicon pellet were calculated as 1.57 n/h, 1.38 n/h and 0.14 n/h, respectively. In addition, YPUE values were determined as 121.84 g/h, 137.73 g/h and 7.62 g/h for natural mud shrimp, siliconized shrimp and silicon pellet, respectively. Despite the fact that the number of individuals that a live mud shrimp catch in a unit of time is high, it was found out that the weight is more in a unit of time when silicone mud shrimp is used. It was concluded that using of siliconized mud shrimp has a high capacity of catching performance and catching efficiency and can be used as bait when natural mud shrimp cannot be utilized as alive or unable to be supplied, due to the weather conditions and time restrictions.

Recovery-from-extinction effects in an anuran amphibian: renewal effect, but no reinstatement.

Recovery-from-extinction effects in which a conditioned response returns after extinction have been shown in mammals, birds and fish. Thus, these effects appear to be conserved among vertebrates; however, they have yet to be investigated in amphibians. Using prey catching conditioning in the fire-bellied toad (Bombina orientalis), we tested if renewal and reinstatement occurred after extinction when subjects were respectively re-exposed to the context or reinforcer used during conditioning. For renewal, a different context was used during extinction and thus renewal tests assessed if external contextual cues associated during conditioning stimulated prey catching performance. For reinstatement, the reinforcer withheld during extinction was simply delivered again prior to a test assessing if internal cues associated with recent prey consumption stimulated prey catching performance. Conditioning followed a fixed ratio 5 schedule of reinforcement, where five attempts to capture a cricket stimulus displayed on a computer screen were reinforced by delivery of a single live cricket. Performance was measured as the time to reach five prey catching attempts. A significant improvement in prey catching performance during conditioning followed by deterioration with extinction was seen in the experiments. Upon return to the context used for conditioning after extinction, toads showed a renewal effect whereby they displayed faster performance during testing compared to the end of extinction. Conversely, toads showed no reinstatement effect because pre-feeding of a cricket did not influence performance during the test that followed extinction. Reinstatement could have been lost in amphibian phylogeny due to secondary simplification of the nervous system.

Relative Catch Performance of Two Gear Modifications Used to Reduce Bycatch of Undersized Fish and Shrimp in Mediterranean Bottom Trawl Fisheries

AbstractThe catch of large quantities of sublegal‐sized fish and shrimp is a pervasive feature of bottom trawl fisheries, particularly in the Mediterranean demersal mixed fisheries where regulations traditionally allow small mesh sizes. To address these concerns, two bottom trawl net selectivity trials were carried out in 2019 and 2020 on fishing grounds worked by the trawl fleet of Spanish Mediterranean, under normal commercial operating conditions with volunteer trawlers of the local fleet. The traditional otter bottom trawl employed in the demersal mixed fishery was modified with a 50‐mm T90 panel on the extension piece under two different configurations (front of the extension piece and back of the extension piece). A second modification consisted of inserting a selective grid in the extension piece of the standard bottom trawl net. The species investigated in the demersal mixed fishery were European Hake Merluccius merluccius, Red Mullet Mullus barbatus, Striped Red Mullet Mullus surmuletus, and the deepwater rose shrimp Parapenaeus longirostris. Important selectivity improvements were observed for European Hake and deepwater rose shrimp, particularly in the selective grid trial, where 95% and 100%, respectively, of undersize specimens escaped through the grid. The design with the T90 panel in the back of the extension piece allowed for a reduction of 35% of sublegal‐sized individuals of European Hake, but no difference was gained in the sizes of both Mullus spp. retained in the cod end. The adoption of these gear modifications might contribute to reducing discards of sublegal‐sized fractions of the fisheries target species.

Individuals With Intellectual Disabilities Rely on Somatosensory Information Rather Than Visual Information to Catch a Ball.

According to the literature, persons with intellectual disabilities have poor motor control in tasks in which motor anticipation is needed. Our study aimed to assess their motor behavior during interceptive tasks (a tennis ball interception with external-and-oneself throw conditions). A stick-bar was used as a reference or to support cloth to occlude a ball's trajectory. Catch performance and interceptive behavior were analyzed (26 persons). The results show that high/low values of the initial approaching movement led to successful/successful catches, respectively. Our results are in line with the literature about the impact of poor motor control on performance in those with intellectual disabilities. We suggest that low anticipation may relate to problems in real-life situations.

Variable Practice May Enhance Ball Catching Skills in Some but Not All Children With DCD

Children with DCD exhibit many motor issues including ball catching, which have not been addressed clinically. The purpose of this study was to examine if variable practice can improve one-handed catching performance of five boys with DCD with severe (M = 11.1 years, SD = .7) and moderate movement problems (M = 11. 7 years, SD = .9). Both groups attended 12 sessions, with 8 blocks of 10 attempts, across four different ball velocities. Children with moderate issues caught more balls at post- and transfer test, as compared to pre-test. Kinematic profiles showed that both groups exhibited stable configuration of the catching arm; however, only children with moderate issues increased (peak) velocity, degree of spatial adaptations, and extended the pre-programmed ballistic phase of the action. Thus, variable practice appeared to be effective for children with moderate issues but not those with severe problems. In line with VPH hypothesis, these improvements were due to strengthening of the schema responsible for spatial and temporal adaptations of the end effector.

Catch Performance of Deep Water Cast Nets Used for Whiting along the Turkish Coast of the Black Sea (Turkey)

Deep water cast net fishing is regarded as a traditional method that has been used since antiquity in the Eastern part of the Black Sea. Unlike ordinary cast nets, it is used in deep waters from shallow up to 140 meters for catching whiting (Merlangius merlangus euxinus). In this study, important findings were obtained about the operational success and duration, catch efficiency and composition of traditional deep water cast nets. The highest operation success rate was obtained from 60 to 120 meter depth with 84.2%. The highest mean CPUE was established at 0.42 kg/operation in August. The catch rate of whiting, the main target species of the study, of the total catch was calculated as 98.8%. In this study, the effect of deep water cast nets on the ecosystem was also investigated. According to the findings, fishing season and operation depth significantly affect the catch per unit effort. In terms of ecosystem-based fisheries management due to high selectivity, the low impact of ghost fishing and high survival rate of the individuals, the deep water cast net fishing was found to be beneficial. It is recommended that the performance of deep water cast nets on different species in different seas should be investigated.

Use of technology in sports- a boon or bane?

Sports has grown into a big industry these days. The professional approach to sports, its commer-cial value and spectator interests has brought about substantial changes in how a sport is played and viewed. These changes has brought about eye catching performances from the players and with more and more spectators enjoying sports, the need to judge the application of laws, rules and regulations governing such sports has also changed drastically. The pressure on umpires, referees and judges to be error free is like never before. Given such circumstances how a game is being evolved, how the spectator’s interest is being cultivated and how the impact of any decision is felt by a player concerned is becoming more critical than ever before. With this background a survey was initiated to gather the opinion of various stakeholders to arrive at some logical conclusion on how technology in influencing Law, Rules and Regulations of Sports and Games and if it needs to be so. A specific questionnaire was designed and circulated among interested participants not only locally but across the world. The responses supported the use of technology in sports today though some of the participants felt that technology may not be an answer as a foolproof method to overcome human error.