Underwater Observation of Puffer Lagoscephalus Behavior to Pot Trap.

Fuwa, Shigeru; Ooishi, Takuya; Ishizaki, Munechika; Imai, Takehiko

doi:10.2331/suisan.64.171

Cited by 3 publications

(4 citation statements)

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“…The diameter of the outer funnel is 180 mm and the entrance ring frame was interconnected with 22 wires of 180 cm long and 1 mm in diameter. This trap is commonly used to catch puffer fish 10–14 …”

Section: Methodsmentioning

confidence: 99%

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Fundamental studies on the hydrodynamic resistance of small pot traps

2004

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The hydrodynamic resistance of small pot traps has been conducted in order to establish some basic information. The specific objectives of the study was to measure the hydrodynamic force and estimate the critical setting condition for traps. Five types of traps with different materials were used in the experiment: a netted semi-cylinder shape, a wire semi-cylinder shape, a heart shape, a box shape, and a cylinder shape. The hydrodynamic force of each trap was measured in a flume tank. Flow speeds in the flume tank were 0.1, 0.2, 0.3, 0.4, and 0.5 m/s. Attack angles for this study were 0, 15, 30, 45, 60, 75, and 90 degrees. At an attack angle of 0 degrees the main axis of the trap was parallel to the water flow and at 90 degrees it was vertical. The values of the hydrodynamic drag coefficient varied with traps: netted semi-cylinder shape, 2.75-5.96; wire semi-cylinder shape, 2.81-4.49; heart shape, 2.77-3.66; box shape, 2.39-2.97; and for cylinder shape, 3.57-3.67. The flow speed (0.5 m/s) was effective to set the netted semi-cylinder, wire semi-cylinder, box, and cylinder shaped traps. The same flow speed applied to the heart-shaped trap was only effective to a maximum of 30 degrees attack angles and below.

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Section: Methodsmentioning

confidence: 99%

“…This trap is commonly used to catch puffer fish. [10][11][12][13][14] The heart-shaped trap ( Fig. 1c) was constructed completely from bamboo strips.…”

Section: Experimental Materialsmentioning

confidence: 99%

Fundamental studies on the hydrodynamic resistance of small pot traps

2004

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“…The diameter of the outer funnel was 180 mm and the entrance ring frame was made of 22 wires 180 mm long and 1 mm diameter. This trap is commonly used to catch puffer fish in Kagoshima Prefecture 5–9 …”

Section: Methodsmentioning

confidence: 99%

“…This trap is commonly used to catch puffer fish in Kagoshima Prefecture. [5][6][7][8][9] The heart shaped trap was constructed completely from bamboo strips. This trap is usually used in Manado, North Sulawesi, Indonesia.…”

Section: Experimental Materialsmentioning

confidence: 99%

Fundamental study on the flow speed distribution around small traps

et al. 2005

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This study measured the flow speed distribution using actual small traps to investigate the effects of their materials and shapes by analyzing the characteristics of the water flow patterns around them. Five types of trap (netted semi-cylinder shaped, wire semi-cylinder shaped, heart shaped, box shaped, and a cylinder shaped traps) constructed from different materials were used in the experiment. The flow speed distribution around each trap was measured in a flume tank. Flow speeds in the flume tank were 0.1, 0.2, 0.3, and 0.4 m/s. The webbing of the traps was different in shape and had various diameters of twine. The diameters of twine ranged from 0.55 to 1.00 mm. The relationship between the solidity ratio of the twine and flow distribution of the traps was also analyzed. For the netted semi-cylinder shaped and cylinder shaped traps, the area of reduced flow speed extended along the downstream area and its width slightly increased with distance from the trap's entrance. The heart shaped trap is shown to have the largest solidity ratio and this resulted in a high reduction of the flow speed downstream from the trap.KEY WORDS: flow ratio, flow speed distribution, solidity ratio, trap.

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Particle filter for automated measurement of chub mackerel trajectory using stereo vision

Sakamoto

Komeyama

Tamaru

et al. 2018

NSUGAF

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The behavior ofˆsh in the vicinity ofˆshing gear and in an aquaculture tank should be analyzed to understand their responses to materials such as nets, tank walls, and other physical objects. To monitor the 3D trajectory of targetˆsh in recorded videos automatically and thereby reduce the workload of scientists, we used a particlê lter as a state-space model, which is an image processing technique, to analyze video. The behavior of a single chub mackerel of fork length of 0.34 m was monitored using stereo vision cameras in an experimentalˆsh tank.Theˆsh body in the recorded video was binarized using threshold and background subtraction methods of image processing. Then, a segmented image of theˆsh body including color information was generated by obtaining the product of the raw image and binarized image. The segmentedˆsh body was automatically tracked in the video recorded by the stereo camera using a particleˆlter. The 3D trajectory of theˆsh was calculated using direct linear transformation methods based on the 2D trajectories in the stereo image. The trajectory was smoothed using the Kalmanˆlter to minimize measurement error in estimatedˆsh position. Thus, using the proposed method based on image processing, we automatically obtained the 3D trajectory of the targetˆsh. Although the wave eŠect inˆeld observation remains an issue in applying this method toˆsheries research, it can be put to immediate use in tank experiments.

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Underwater Observation of Puffer Lagoscephalus Behavior to Pot Trap.

Cited by 3 publications

References 0 publications

Fundamental studies on the hydrodynamic resistance of small pot traps

Fundamental studies on the hydrodynamic resistance of small pot traps

Fundamental study on the flow speed distribution around small traps

Particle filter for automated measurement of chub mackerel trajectory using stereo vision

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