Language：Japanese   Publisher：瀬戸内海環境保全協会  

Language：Japanese   Publisher：Japan Driftological Society  

Marine litter is flowed out from the land area through the river and into the sea. Several survey methods for scattered litter along the coasts and rivers have been created, however these were not effective and efficient survey methods for land based roads cattered litter. In May 2019, we attempted a quantity survey that applied a visual survey method at 43.9 km around Osaka Nanko Port and on 18.9 km around the Osaka city hall. The amount of litter scattered on the roads in both areas was 462 bags and 1bag （20Lbag）. The most scattered area was harbor warehouse area in Osaka Nanko Port with a density of 0.24 bags/10m. A survey of cigarette butts scattering was also attempted on roads in both regions. At the results, 1,795 and 1,183 cigarette butts were scattered in each regions. The largest scattering area of cigarette butts was the main road of Osaka Nanko Port, with a density of 1.10pieces/10m.

DOI： 10.57279/driftological.17.0_5

Language：Japanese   Publisher：湊文社  

Language：Japanese   Publisher：日本工業出版  

Language：Japanese   Publisher：日本工業出版  

Language：Japanese   Publisher：産業開発機構  

Language：Japanese   Publisher：Japan Driftological Society  

Distribution and composition of micro （1.0-4.0mm） and meso （4.0-25.0mm） plastic debris were investigated on 20 beaches of Ago Bay and Gokasho Bay， Mie Prefecture， in September 2014. The total of collected plastic debris were 111,080 items and the plastic fragments accounted for 98.1% of the total number. Micro plastic debris accounted for 89.9% of total number and the average densities were 34,713 pieces per m2. Micro and meso plastic debris of average densities over 50 pieces per m2 were seven items and these were consisted by foamed plastic fragments （96.5%）, capsule of chemical fertilizers （1.6%）, hard plastic fragments（0.7%）, line fragments（0.3%）, plastic film fragments（0.2%）, resin pellets（0.2%） and tips of synthetic lawn（0.1%）. The maximum density of foamed plastic fragments was at Yadoura（158,602 pieces per m2） and the average density（33,499 pieces per m2） was about ten times for the beaches of Ise Bay.

DOI： 10.57279/driftological.15.0_1

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publisher：産業開発機構  

Language：Japanese   Publisher：Japan Driftological Society  

Distribution and composition （items and size） of drifting micro plastics （1mm <） were investigated at 31sites between 10, Aug. and 22, Sep. 2012 on the sea surface of western and central North Pacific Ocean. And distribution and composition （items and size） of grounded micro plastics （1mm <） were investigated at 5 coasts （7 sites） between Jun. 2011 and Jun. 2013 on the beaches of west coast of North America and remote islands in the North Pacific Ocean. The Maximum density of drifting micro plastics was over 130,000 pieces per km2 on the central area of North Pacific Ocean, and the hard plastic fragment was the highest density in this area （average 75.4％）. The Maximum density of grounded micro plastics showed over 60,000 pieces per m2 on the beach of Island of Hawaii, and the hard plastic fragment was the highest density in these sites （over 80％）. Major items of micro plastics on the sea surface of the North Pacific Ocean were hard plastic fragments, and others were filmy plastic fragments, lines and fiber and resin pellets. They were recognized on the beaches of remote islands in the North Pacific Ocean and west coast of North America.

DOI： 10.57279/driftological.13.0_1

Language：Japanese   Publisher：Japan Driftological Society  

Flow and sources of marine litter washed up on the remote island coasts in the North Pacific Ocean and on the west coast of North America were estimated using disposable lighters because those items have the out flow information of country or location. The outflow country can be classified by a body shape and punched codes on the tank bottom, and the outflow location can be distinguished by a shop address or telephone number printed on the tank surface. From August 2003 to December 2014, total of 6,430 lighters were collected on the 124 beaches. Flow of lighters elicited by the relationship from the outflow locations to the collected sites was as follows: The lighters flowed out of the East Asia （include Japan） wash up on the remote islands of Northwest Hawaiian Islands to Hawaiian Islands while drifting eastward in the North Pacific Ocean, and they reach to the west coast of North America, although the number is a little. After 3.11 tsunami, the lighters from east coast of Japan （Tohoku region） increased on the Midway Atoll. Main outflow areas of lighters were the Pacific coast side of East Asia. In Japan, it is same side including those enclosed water area of Tokyo Bay, Ise Bay and Seto Inland Sea.

DOI： 10.57279/driftological.13.0_35

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publisher：日本工業出版  

Language：Japanese   Publisher：Japan Society of Civil Engineers  

&nbsp;Marine debris issues have gained a significant concern recently due to their impacts to coastal and marine environments. Knowledge on their abundance, distribution and seasonal variation are still limited in many aquatic environments including Kagoshima bay. This study was conducted in three phases from the year 2010 to 2014. Field study in Oosumi peninsula and along Kotsuki river was conducted on November, 2010 to investigate the abundance and distribution of micro size debris. Then, in Kagoshima bay three field studies were carried out to investigate spatial distribution and seasonal changes of marine debris along its coastline and on sea surface from the year 2011 to 2014. Kagoshima bay opens to the south of Kyushu island and is affected by Kuroshio current which probably carries marine debris into the bay. In addition there are several major rivers which carry debris into the bay. The size of the bay is similar to Tokyo bay, therefore field studies in and along its coastline can be representative study to reveal qualitative and quantitative characteristics of marine debris inside a bay in Japan. As a result, EPS fragments dominated the distribution in almost all surveyed beaches (over 90%). Rainfall and natural disasters (i.e. typhoon) contributed significantly to higher deposition levels of micro debris on beaches.

DOI： 10.2208/jscejoe.71.I_503

Language：Japanese   Publisher：Japan Driftological Society  

In August 1998, massive amounts of marine litter washed up along a stretch of the western coast line of Japans Kyushu region（Satsuma Peninsula in Kagoshima Prefecture）. Soon thereafter, marine litter monitoring began at Fukiagehama Beach on the same coast, and has been conducted monthly for the past 15 years. Since 2009, the monitoring program has provided warning alerts for massive marine litter drift, with the severity of the alerts based on the composition of the source regions and density of the indicator items. In July 2013, very large amounts of marine litter accumulated once again on the same coast. The density of the drift had increased by more than 30-fold compared with last month. The warning alerts for massive marine litter drift were given in this coast line in July 29, 2013 because the density of indicator items was greater than the warning value. The character was that a massive drift from a foreign source was spotted. Disposable lighter was used as an indicator item to identify the source regions as the probable sources of the marine litter. Specifically, the major out flow area was Meizhou City in Guangdong, China. The massive drift was thought to be a result of typhoon Soulik, which caused excessive flooding and destruction in the source regions. In addition to the disposable lighters from China and Taiwan, both blue and orange spindle-shaped plastic floats were used as indicator items from China and Taiwan; the accumulation of these items was estimated to have increased at rates of more than 96-fold, 108-fold, and 52 fold, respectively compared with last month, and some disposable syringes were also found ashore in the surveyed area. However, there are few domestic items. The massive marine drift alert was in place for 5 months until November 2013.

DOI： 10.57279/driftological.12.0_9

Language：Japanese   Publisher：Japan Driftological Society  

Flow and sources of marine litter washed upon the coast of Japan were estimated using the disposable lighter because it has the outflow information of country or location. The outflow country can be classified by a body shape and punched codes on the tank bottom, and the outflow location can be distinguished by a shop address or telephone number printed on the tank surface. From Aug. 2003 to Mar. 2014, total 63, 140 lighters were collected on the total 1,434 beaches（1,384 in Japan, 36 in Taiwan, 9 in Korea, 4 in Russia and 1 in China）. Flow of lighters elicited by the relation ship the outflow location with the collected site was as follows: The lighters flowed out of the Chinese coast from Hong Kong to Shanghai and the west coast of Taiwan mainly wash upon the remote islands area from Yonaguni Island （Okinawa prefecture） to Amami Islands （Kagoshima prefecture） while drifting north ward in the East China Sea, and they inflow to Japan Sea through the Tsushima Strait. A little number of lighters flowed out of western Korea drift southward, however Korean lighters mostly inflow to Japan Sea. The lighters flowing into Japan Sea directly and through the strait drift northward and then outflow to the Pacific Ocean through the Tsugaru Strait. They drift southward along the Tohoku Pacific coast and reach to the area off Ibaraki prefecture. The lighters drifted northward along the west coast of Hokkaido reach to the area off Shiretoko Peninsula in Okhotsk Sea through the Soya Strait. On the pacific coasts from the southern Kyushu to Tokai area, the lighters flowed out of the around inland area mainly wash up. These flows illustrated by the movement of lighters are basically consistent with the ocean currents
around Japan reported in previous oceanographic studies.

DOI： 10.57279/driftological.12.0_29

Language：Japanese   Publisher：生物研究社  

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publisher：生物研究社  

Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publisher：Japan Driftological Society  

Effective plans and strategies for mitigating the marine litter issue need to be implemented. It is crucial to have a comprehensive budget in an effort towards addressing this issue. The marine litter budget in the Seto Inland Sea that was the largest closed water area in Japan was therefore estimated. It was realized that, effective and dramatic reduction of marine litter standing stock in this area will be difficult, if promotion of litter collection and prevention of stock build up are the only strategies. Based on these findings, reduction of the marine litter standing stock, effective collection process and sustainable mitigating efforts through the social marketing method are here by discussed.

DOI： 10.57279/driftological.11.0_13

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese  

Language：Japanese   Publisher：鹿児島県自然愛護協会  

type:論文(Article)

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publisher：The Japanese Society of Fisheries Science  

&nbsp;&nbsp;Plastic pipes are a major item of beach litter on the shores of the Seto Inland Sea. They are also frequently seen on the shore of the north Pacific. This paper investigates the scattering of plastic pipes on the coast of the Seto Inland Sea. The pipes are used in oyster farming, and are divided into &ldquo;pipes&rdquo; about 205 mm long used for hanging, &ldquo;broken pipes&rdquo; cut at harvesting time, &ldquo;short pipes&rdquo; about 15 mm long used for spat collection and &ldquo;washers&rdquo; attached to the end of collectors. Scattered pipes were collected from 251 beaches, and the locations of drifting pipes on the sea surface were verified by visual observation from a ship. On average, 7.5 short pipes, 4.5 broken pipes and 2.9 pipes were found per m² of beach. The discovery rate of pipes, broken pipes and washers on the coast was higher in the western part of the Seto Inland Sea than in the eastern part. The average density of pipes and broken pipes floating on the sea surface tended to vary in the same way as their presence on the coast. Short pipes, however, were relatively evenly distributed along the entire Seto Inland Sea coast.<br>

DOI： 10.2331/suisan.77.23

Scopus

Language：Japanese   Publisher：日本沿岸域学会  

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publisher：日本沿岸域学会  

Language：Japanese   Publisher：鹿児島県自然愛護協会  

type:論文(Article)

Language：Japanese   Publisher：日本沿岸域学会  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publisher：日本沿岸域学会  

Language：Japanese   Publisher：生物研究社  

Language：Japanese   Publisher：The Japanese Society of Fisheries Science  

&nbsp;&nbsp;Sampling surveys using a small trawl net were conducted 118 times (May 2003-Oct. 2005) to estimate the distribution and composition of seabed litter at eight stations established in Kagoshima Bay. The sediments collected from the sea bottom contained 54,388 items, 76.9 kg of natural objects and seabed litter. The average density of seabed litter was 2,517 items/km² and 30.3 kg/km² accounting for 3.7% of the total sediments by number. The dominant type of deposited litter on the sea bottom was filmy plastic including plastic bags accounting for 49.0% of seabed litter by number. Seabed litter was found at all stations in Kagoshima Bay whether or not the station was in a fishing ground. The density distribution of filmy plastic was higher in the innermost and central area of this bay similar to the distribution of plant leaves.<br>

DOI： 10.2331/suisan.75.19

Scopus

Language：Japanese   Publisher：日本沿岸域学会  

Language：Japanese   Publisher：瀬戸内海環境保全協会  

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publisher：鹿児島大学  

type:論文(Article)

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：Japanese   Publisher：鹿児島大学  

type:論文(Article)

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：Japanese   Publisher：全国都市清掃会議  

Language：Japanese   Publisher：日本沿岸域学会  

Language：Japanese   Publisher：漂着物学会事務局  

Language：Japanese  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：日本沿岸域学会  

Language：Japanese   Publisher：漂着物学会事務局  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：Japanese   Publisher：海洋水産システム協会  

Language：Japanese   Publisher：The Japanese Society of Fisheries Science  

&nbsp;&nbsp;Expanded polystyrene (EPS) floats are used abundantly for the floats of oyster farming rafts in Hiroshima Bay. This paper investigated the occurrence of stranded debris of foamed plastics, stranding and unsuitable use of EPS floats on the coast of Eta and Kurahashi Islands in the Bay. Stranded debris of foamed plastic was collected from sand samples of 34 sites. Stranded floats on the beach and unsuitably used floats without covers for mooring buoys and fenders on the sea were observed visually at 58 sites along 48.6 km of coastline.<br> &nbsp;&nbsp;The total number of collected debris was 245,656 items. Plastics accounted for 99.9% of the total number. Foamed plastic fragments accounted for 99.5% of the total, the size of under 10.0 mm represented 98.5% of the fragments, and the average density was 44,521.3 pieces per m². Unsuitably used floats totaled 6,760, and the density was 140.7 pieces per harbor. The density of stranded floats was 1.1 pieces per km. The densities of unsuitably used floats, stranded floats and foamed plastic fragments on the coast of Eta Island were higher than those of Kurahashi Island.<br>

DOI： 10.2331/suisan.71.755

Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publisher：Kagoshima University  

In 1986, the Coastal Cleanup by the Center for Marine Conservation started in Texas, USA. In 1989, the International Coastal Cleanup (ICC) has been organized with Canada and Mexico's participants, and Japan has taken part in it from 1990. The International Coastal Cleanup engages people to remove trash and debris from the world's beaches and waterways, to identify the sources of debris, and to change the behaviors that cause pollution. Four coordinators (captains) who initiated the event in Kagoshima in 1999 established Cleanup Kagoshima Office. From 1999 to 2004, the 10,418 volunteers removed the marine debris of 458,699 from Kagoshima coasts. In this report, the results of six years including last year are introduced.

Language：Japanese   Publisher：廃棄物学会  

Language：Japanese   Publisher：漂着物学会事務局  

Language：Japanese   Publisher：廃棄物学会  

Language：Japanese  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publisher：緑書房  

Authorship：Last author   Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)   Publisher：鹿児島女子短期大学附属南九州地域科学研究所  

Publisher：The Japanese Society of Fisheries Science  

Foamed plastic fragments are major beach litters in the world. This paper investigates the occurrence of grounded and buried fragments on the coast of Kagoshima prefecture, Japan. Sand samples were collected for gathering the grounded and buried debris at 77 strand lines on 68 beaches from July 30, 1998 to November 26, 2000. After the sand was stirred in water, floating materials were scooped up with a testing sieve (0.3 mm openings) . Floating man-made debris (e. g. foamed plastic fragments, plastic fragments, plastic resin pellets, etc.) were sorted, dried and divided into three size groups with testing sieves (4.0 mm and 10.0 mm openings) and their numbers were counted. The grounded and buried foamed plastic fragments were verified at 74 strand lines on 65 beaches. Collected beach litter had a total of 80, 655 pieces. Plastics accounted for 99.9% of the total number. Foamed plastic fragments accounted for 92.6% of the total, and the size range 0.3-4.0 mm represented 91.0% of foamed plastic fragments. The highest density was observed on the east coast of Kagoshima Bay, and the average density was 290.4 pieces per liter. Although fragments also existed on the coast of the Amami archipelago in Kagoshima prefecture, the percentage (63.9%) was lower than on the other coast. It was presumed that the origins of the foamed plastic were the fenders of fishing boats and floats of aquaculture pens which had been washed up onto the beaches and weathered into small fragments.

DOI： 10.2331/suisan.68.652

Language：Japanese   Publisher：日本海難防止協会  

Language：Japanese   Publisher：Kagoshima University  

It is very important to utilize radar effectively in order to avoid collisions between vessels and sea kayaks, as well as to be able to find wrecked sea kayaks promptly. To facilitate this, radar cross sections of sea kayaks were measured in the touring, wrecked (drifting) and overturned conditions. The results obtained in this study were as follows : 1. The radar cross section was 0.503m^2-0.017m^2 for a single sea kayak, and 0.725m^2-0.011m^2 for a tandem sea kayak. 2. The radar cross section was largest when the side of sea kayak faced the radar antenna, and was smallest when its bow or stern was towards the antenna. 3. The manned sea kayak gave larger radar cross section than the unmanned ; 6dB at single and 8dB at tandem. 4. The radar cross section and the geometric cross section for each azimuth aspect angle showed almost the same patterns.

Language：Japanese   Publisher：Japan Institute of Navigation  

DOI： 10.18949/jinnavi.151.0_79

Authorship：Last author   Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)   Publisher：鹿児島女子短期大学附属南九州地域科学研究所  

Publisher：The Japanese Society of Fisheries Science  

The present conditions of fishing debris used for marine culture (Net-cage raft and frame, foamed float) were observed visually on the coast of Kagoshima Bay. Foamed floats were classified into three types (Grounded floats, Floats for marine use, and Floats for land use). Grounded floats are grounded foamed floats on the coast. Floats for marine use are foamed floats without covers used for mooring buoys, fenders, and fishing floats on the sea. Floats for land use are foamed floats without covers used or stocked on land. Grounded floats were observed on the whole coast of Kagoshima Bay. There were a total of 3, 043 Grounded floats, and the average density of Grounded floats was 10.3 pieces/km. The highest density fishing district was on Ushine (38.9pieces/km). The total number of Floats for marine use was 4, 856, and the total number of Floats for land use was 1, 344. Floats for marine use (80.2%) were used for mooring buoys and fenders of pleasure boats in harbors. The total number of grounded net-cage rafts was 127 pieces, and the total number of frames was 223. These have been mainly grounded around the coast of areas used for agviculture.

DOI： 10.2331/suisan.66.236

Language：Japanese   Publisher：Kagoshima University  

The underwater sound environment in shallow water area was complicated by time and depth under the influences of the biological and artificial noises from land and sea, e.g., trains, cars, feeding, cruising boats, etc. The purpose of this study is to clarify the underwater noise background and the underwater sound environment weighted by auditory sensation of fish in Kagoshima Bay. The emitted noise by drifting and cruising vessels has the largest influence on the underwater sound environment in shallow water area. There were recorded the vertical underwater noise by drifting vessel and approaching noise by cruising vessel. The transmission rays of underwater noise by drifting vessel have two directions, i.e., direct and reflected rays ; interference occurs while receiving the two direction sound waves with a hydrophone simultaneously. As an interference theory of underwater sound in shallow water was obtained as an equation with the range of transmission rays from drifting and cruising vessels to hydrophone for the reflection number. A comparison between theoretical and actual interference was made with a measurement of the ambient noise and traffic value in the heavy traffic area of Kagoshima Port. It was confirmed that the main noise was emitted by vessels, and the characteristic noise was temporal and sharply increased. In the biological noise, the underwater sounds measured in net cages at a culture ground were analyzed by the zerocrossing method to obtain the period change, power, and continuation time of swimming sounds by fish. The audiogram of a bastard halibut Paralichthys olivaceus was measured by a classical respiratory conditioning technique. The hearing response of bastard halibut was also measured by sweeping sound, and clarified the upper limit frequency of hearing. The lowest threshold of bastard halibut was at about 100 Hz and the threshold increased rapidly at 200-400 Hz. The ambient noises are mainly broadband and appears under 3 kHz of fine auditory sensation in fish. The hearing ability differs among fishes, thereby the underwater sound environment also differs. Arrangement was made on the frequency-weighted characteristics for auditory sensation of fish, fish weighting using these audiograms, in comparison with the underwater sound environment and underwater noise level of each fish. The fish weighting of bastard halibut is a type of low frequency with narrow band ; the underwater noise level is strongly affected by emphasis on the interference level of low frequency. The fish weighting of a Japanese horse mackerel Trachurus japonicus is a type of high frequency with wide band ; the underwater sound environment is influenced by the interference with wide band, but a small effect on variation of the underwater noise level.

Language：Japanese   Publisher：Kagoshima University  

This paper deals with beach litters collected along the coast of Kagoshima prefecture from April 1997 to July 1999. One hundred and sixteen persons swept over 9-km shoreline from Iso to Shikine for 26.4 hours. The total beach litters collected were 805.7 kg or 289 bags (4.5 l /bag). The most abundant items were papers and plastics accounting for 408.9 kg (50.6%) or 123 bags (42.5%). On the other hand, the beach litters collected in an area of 100 m^2 on 7 beaches were roughly classified into 117 items. The litters were mainly composed of plastic pieces (11.0%), plastic pellets (34.4%), and foamed plastic pieces (40.5%). About 90% of the total beach litters were fine fragments including plastic pellets. The lowest efficiency of collection on the shoreline was 1.3 m/(p-h) at Kanze in Kagoshima City. In the plastic pellets drifted onto 15 beaches were contained more than 100 pieces in an area of 100 m^2.

Language：Japanese   Publisher：The Japanese Society of Fisheries Science  

The target strength (TS) of Japanese horse mackerel was measured by using split-beam echo sounder. The target was kept at the position of dorsal direction incidence and moved across to the beam. Characteristics of TS directivity pattern and measuring precision of position angle by split-beam method were estimated. As a result, TS pattern in pitch plane shows drastic variation. Beside that, the fluctuations of position angle were increased. I took notice the coherent scattering of fish body structures, also examined the difference of phase in carrier wave. And we discussed the relationship between fish body structures and interference.

DOI： 10.2331/suisan.65.414

Scopus

Language：Japanese  

Language：English   Publisher：The Japanese Society of Fisheries Science  

The differences between swimming and feeding activity of recorded underwater sound in summer and winter produced by Japanese horse mackerel in a net pen were analyzed using the one-third octave band method. The small and big-sized fish show the same curve patterns under swimming and bait-eating activity in summer, but in the term of the maximum and minimum level frequencies, it seems slightly different. The swimming sound curve pattern in summer was same as in winter, but there were some different patterns in bait-eating sound. The two respective records obtained simultaneously on the inside and outside of net pen when swimming activity were same in regard to the pattern and sound level, but the records when bait-eating activity were different.

DOI： 10.2331/fishsci.65.398

Scopus

Language：Japanese  

Publisher：The Japanese Society of Fisheries Science  

The underwater noise emitted by a cruising vessel has several transmission rays namely direct ray and reflected rays from the sea bottom and sea surface. Interference occurs when the sound waves are received at a hydrophone simultaneously. Actual interference of underwater noise was observed in sea areas of 24m and 70m depth. Observed underwater noise emitted by an approaching vessel at 9 knots was analyzed every 10 sec at a distance of 0.5 mile from the closest point of approach, and a spectrogram was calculated from the spectrum data. The theoretical interference of underwater noise in shallow water was obtained using an equation that considered the range of transmission path from the cruising vessel to the hydrophone as the reflection number. This report compares the theoretical and actual interference.<br>The characteristics of interference were obtained. Numbers of transmission rays by the theoretical interference (&mu;=0.5) were more than six rays at 0.5 mile away, but at 0.05 mile from tue closest point of approach, the number decreased to two rays. This was becouse the reflected transmission range is much longer than the direct one, so the reflected sound pressure level is lower than the direct sound pressure level at short range. If the reflection number at the sea bottom increased, the reflected sound pressure level decreased in inverse proportion to the reflection number (at the sea bottom) power of &mu;. Therefore, the spectrum pattern will change with the amplitude reflection coefficient at the sea bottom (&mu;). A theoretical interference striped pattern appeared for the shallow water rather than the deep water. Actual interference striped pattern appeared for the aes area of 24m depth at all hydrophone depths and the sea area of 70m depth at 5, 10, 60m hydrophone depths. This conforms with the theoretical pattern for the sea area of 24m depth of all hydrophone depths.

DOI： 10.2331/suisan.64.48

Publisher：JAPAN SOC SCI FISHERIES SCI  

The hearing sensitivities of bastard halibut Paralichthys olivaceus decreased sharply at the frequency band between 200 Hz and 400 Hz. The hearing response of bastard halibut was measured by sweeping sound which the center frequency moves from non-hearing frequency (300-1600 Hz) to hearing frequency (100-200 Hz), and discussed the upper limit frequency of hearing.
The classical conditioning was reinforced by the tone burst sound in a continuous time of 1 s, a frequency of 100 Hz and a sound pressure level of 131 dB. The sweeping sound was projected in five steps at intervals of 5 dB. The sweeping speed of eight types was adjusted with a combination of a start and end of sweeping frequency. The conditioning response was measured as suppression in the respiratory activity by a piezoelectric sensor fitted on the gill cover.
The response to sweeping sound was 82% at the frequency band between 200 Hz and 340 Hz, which agreed with the boundary of the hearing area. The upper limit frequency of hearing of bastard halibut existed under 500 Hz. The hearing response to sweeping sound did not agree with the audiogram of bastard halibut because the sound pressure level fluctuated in the small water tank. The sweeping speed is inversely proportional to the individual difference of the response time.

DOI： 10.2331/fishsci.64.870

Web of Science

Scopus

Language：Japanese   Publisher：Japan Institute of Navigation  

DOI： 10.18949/jinnavi.137.0_6

Language：English   Publisher：The Japanese Society of Fisheries Science  

This paper examines the differences in the features of sounds produced by yellowtails and amberjacks of different size during swimming and bait-eating activities in a net pen. Recorded underwater sounds were analyzed by the one-third octave band method.<br> The overall underwater ambient noise levels in the Tarumizu and Furue waters were 108.6 dB and 106.4 dB, respectively. The sound levels of yellowtail were 102.8-116.0 dB during swimming and 113.4-124.8 dB during bait-eating. The sound levels of amberjack were 109.4-110.2 dB in the swimming activity and 115.3-121.9 dB in the bait-eating activity. The sound level in the bait-eating activity was higher than that in the swimming.<br> Graphs of one-third octave band analysis of the underwater sounds in the two activities could be classified in four specific patterns. The curve patterns indicated some relationship with sizes of the fish. Frequencies at the minimum sound level in a concave part of the pattern and at the maximum level in the swimming and bait-eating activities were higher for the small-sized fish and vice versa. Both frequencies of the amberjack sounds were lower than those of the yellowtail sounds in the respective sizes and activities.

DOI： 10.2331/fishsci.64.353

Scopus

Publisher：The Japanese Society of Fisheries Science  

Transmission ray of underwater noise emitted by drifting vessel have two direction i.e. direct and reflected rays. Interference occurs to receive the mixed sound wave from both rays at a hydrophone. The present research compares a theoretical interference with the basis of actual measurements of interference.<br>We observed vertically underwater noise emitted by drifting vessel with intervals one meter on 26m depth and 93m depth sea area. Also spectrogram by spectrum data was made in each depth. The results, at both stations the same striped patterns appeared on a range of about 13m and 16m from sea bottom, and on the frequency range of over 50Hz. By theoretical pattern, this spectrum level changed with their phase differences, and the interference relate to the depth of a hydrophone from the sea bottom rather than the depth of sea area. If the frequency increased, the term pattern decreases. That observed patterns coincided with a theoretical interference patterns by both waves at the frequency range of over 100Hz. A great term pattern appeared at the shallow sea area rather than the deep sea.

DOI： 10.2331/suisan.63.213

Language：Japanese  

Language：Japanese  

Publisher：The Japanese Society of Fisheries Science  

Using a classical respiratory conditioning technique, this experiment was carried out to examine the possibility of using a piezoelectric sensor (Kynar; 20mm long, 0.2mm thick) to observe a conditioned response. We used 2 fishes of different body style, the bastard halibut <i>Paralichthys olivaceus</i> and the tilapia <i>Tilapia niloticus</i>. The sensor was fitted on a gill cover to detect the respiratory activity, opening and shutting motion. The heart-beat was detected by ECG. After classical conditioning, the conditioning response was measured as suppression both in the respiratory activity and the heart-beat. The two factors coincided with each other. The method of measuring the respiratory activity by the piezoelectric sensor was found to be very useful for measuring the auditory threshold because of its ease of operation, apparent response and greater signal than that of the ECG.

DOI： 10.2331/suisan.62.40

Publisher：Nippon Suisan Gakkaishi (Japanese Edition)  

DOI： 10.2331/suisan.62.201

Scopus

Language：English   Publisher：鹿児島大学  

Some Biological Aspects of Oceanography

Language：Japanese   Publisher：The Japanese Society of Fisheries Science  

The purpose of this paper is to investigate the auditory threshold of Japanese horse mackerel which is one of the important pelagic fish for Japanese fisheries. The hearing of fish was studied by means of a cardiac conditioning technique. Classical conditioning method was performed with the sound coupled with a delayed electric shock. The threshold was determined by analyzing the elec-trocardiogram. The sensable frequencies ranged widely from 70Hz to 3000Hz which was most stimulative to the Japanes horse mackerel. As the frequency becomes higher than 70Hz, the auditory threshold decreased. At 1000-1500Hz (sound pressure 81-75dB) when the fish's hearing was most sensitive, the threshold tends to increase more than one. Lastly, it was assumed that a round haul netter traffic noise caused an escape action for the fish shoal.

DOI： 10.2331/suisan.61.695

Scopus

Language：Japanese   Publisher：The Japanese Society of Fisheries Science  

The underwater noise emitted by fishing boats is one of the main noise sources in coastal fishing grounds. This paper intends to investigate the underwater noise emitted by fishing boats, by means of measuring both drifting and cruising noise for small trawlers and medium purse seiners.<br> The spectrum of noise when drifting showed some harmonics (line component spectrum) of basic frequency which corresponded to the main engine and generator revolution pitch. The noise at cruising showed a powerful continuous component spectrum above 50 Hz frequency zone to the propeller influence as well as line components spectrum. It dominated when applied to full speed ahead and astern. The sound spectrogram of underwater noise emitted by fishing boats when cruising showed furthermore doppler phenominon and interference. These functions at cruising were influenced by distance from noise source, depth, reflection number, main engine and generator revo-lution, and cruising speed.

DOI： 10.2331/suisan.61.553

Scopus

Publisher：The Japanese Society of Fisheries Science  

Auditory thresholds of the tilapia <i>Tilapia niloticus</i> in a quiet water tank were investigated using a classical conditioning procedure in a stable temperature container converted into an acoustic chamber. The classical conditioning procedure followed Ishioka's method. Tilapia could hear a sound band width ranging from 100Hz to 1500Hz with maximum sensitivity 300Hz where the threshold was below 103.5dB (0dB re 1&mu;Pa). The background noise in the range of measurement frequency were in a low level of 37-47dB (0dB re 1&mu;Pa/&radic;Hz), and signal/noise ratio in this investigation was above 50dB. Nevertheless the audiograms for tilapia from 100Hz to 1000Hz were significantly higher than in the red sea bream. It is evident that the auditory capacity of tilapia is poor, as compared to that of the red sea bream tested by the same method.

DOI： 10.2331/suisan.61.320

Publisher：The Japanese Society of Fisheries Science  

The paper describes the period change, power, and continuation time of swimming sounds by fish. The underwater sounds measured in net cages at the Hayato culture ground were analyzed with the zero-crossing method.<br> The results show that: 1) the swimming sound of fish schools had periods from 4ms to 100ms; 2) histograms of zero-cross periods for yellowtail and amberjack were sharp with one mode; red sea bream, mode with a shoulder; amberjack, bimode; and tiger puffer, mode; 3) high-speed swimming sounds by large-size fish consisted of pulse waves of narrow-range periods; 4) the swimming sounds of small and/or altering-speed fish largely changed in period; 5) the present method makes. it possible to separate swimming sounds of fish from ambient noise and to detect small power swimming sounds by fish such as tiger puffers.

DOI： 10.2331/suisan.60.201

Language：Japanese  

Language：Japanese   Publisher：鹿児島大学  

type:論文(Article)

Publisher：The Japanese Society of Fisheries Science  

We tried to analyze the spectrum of echo scattering patterns from individual fish, in order to clarify the cause of periodic changes in dorsal aspect scattering patterns. Targets of individual fish of three species were measured in three states, whole, without bladder, and skeleton. The power spectrum was calculated from scattering patterns which transformed to distanceamplitude co-ordinates from incidence angle-amplitude co-ordinates. The elemental patterns and power proportion of each frequency band were calculated by using convolution integration of the power spectrum and filter-fuction in the frequency region. Analysis shows that a relationship was observed between fish species, or fish figure, and the characteristics of the changing period.

DOI： 10.2331/suisan.59.1701

Language：Japanese   Publisher：鹿児島大学  

type:論文(Article)

Language：Japanese   Publisher：鹿児島大学  

type:論文(Article)

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)   Publisher：産業開発機構  

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)   Publisher：瀬戸内海環境保全協会  

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Meeting report  

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：Japanese  

Language：Japanese   Publisher：日本沿岸域学会  

CiNii Books

Language：Japanese   Publisher：日本沿岸域学会  

CiNii Books

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)   Publisher：海洋水産システム協会  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：廃棄物学会  

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)   Publisher：緑書房  

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)   Publisher：日本海難防止協会  

Event date： 2011.11

Language：Japanese  

Venue：東京都  

国内学会

Event date： 2011.10

Language：Japanese  

Venue：高知県黒潮町  

国内学会

Language：Japanese   Presentation type：Symposium, workshop panel (nominated)