Yoshinori MIYAMOTO, Tamami SAKAI, Masahiko FURUSAWA, Yasuhiko NAITO (2004): Development of high-frequency micro echo sounder. Fisheries Science; Volume 70, Issue 3, Page 381-388
Abstract: The authors have developed a micro echo sounder operating at a frequency as high as 1 MHz, which can be attached to aquatic animals in combination with a depth and temperature sensor to obtain information on the animal's prey as well as its behavior. The performance of the sounder was evaluated in an experimental tank and its detection range was estimated to confirm its effectiveness. The beam width is 5.9� and the maximum detection distance is estimated as 34 m when the target strength of an object animal is 50 dB. Link: http://www.blackwell-synergy.com/links/doi/10.1111/j.1444-2906.2004.00817.x Seiji OHSHIMO (2004): Spatial distribution and biomass of pelagic fish in the East China Sea in summer, based on acoustic surveys from 1997 to 2001. Fisheries Science; Volume 70, Issue 3, Page 389 ff Abstract: Annual acoustic surveys were conducted using a quantitative echo sounder (frequency: 38 kHz) in the East China Sea from July to September of 1997-2001. Three groups of fish were identified from the echograms, based on school shape and swimming depth characteristics: (i) anchovy Engraulis japonicus and round herring Etrumeus teres; (ii) jack mackerel Trachurus japonicus and chub mackerel Scomber japonicus; and (iii) lantern fish Diaphus spp. and pearlside Maurolicus japonicus. The area backscattering strength (Sa) of each group was divided by the total weight of fish species caught in midwater trawls. Anchovy, round herring, jack mackerel, lantern fish and pearlside were the most abundant. The estimated biomass indices of anchovy and round herring were positively correlated with the commercial landings of these species, indicating the usefulness of acoustic surveys. Link: http://www.blackwell-synergy.com/links/doi/10.1111/j.1444-2906.2004.00818.x Sincerly, Sonja Amoser Mag. Sonja Amoser Institut of Zoology, University of Vienna Althanstrasse 14, 1090 Vienna, Austria Tel: +43-1-4277-54515 Mail: [EMAIL PROTECTED]
