深海生物をワイヤ繋留の籠で採集する試み(予報)

Since 1947 we have been using a RUSSEL-type beam trawl for sampling of the benthos. To collect more abyssobenthic specimens for radionuclide analysis, we operated bottom-set traps at 36°35'N-141°58'E in Nov 27-28, 1981 (Fig. 2). The form of the trap is a frustum. The framework is constructed of 9-mm diameter steel rods; the top ring of 60 cm diam., middle 80 cm and base 90 cm with the depth of 50 cm, connected with 6 rods. The webbing consists of 2 kinds of netting; knotted brown Hi-zex ® (3/12) of 27.5 mm mesh size or knotless green RUSsEL net (polypropylene 400 D/10) of 13.0mm, and base netting is fastened with rubber bands. On both sides of the trap, 2 funneled nonreturn entrances (15-, 22 cm × 20 cm) are fitted up for the ushering of animals into the net. A trap weighs 6.0 kg in air and 4.5 kg in water (Fig. 1). At the top ring of each trap, 4 Hi-kure ® ropes (10-mm diam. × 1 m) were attached and they were united into a Hi-zex ® rope (14-mm) of 3m branch line, and the end of the branch was tied to an eyesplice of Manila rope on main line: Dan-line ® cross rope (18-mm). Traps were connected at intervals of 10 m and a string of 8 traps was joined at intervals of 30m. On the 630m main line, syntactic foam floats were attached at 210 and 420 m from the end with shackles. Instead of the buoy line, we used tapered 10,000 m wire (9, 11, 12-mm diam.). The arrangement of the trap fishing rig: 10,000 m wire-80m line-1st string of 8 traps-2nd-3rd-4th-5th-80m line-50 kg sinker (Fig. 3). We baited one whole mackerel in each of the traps: lot-I mackerel only, lot-II chopped sardine held in a plastic basket, lot-III a luminous plate of ¹⁴⁷Pm (two 120 × 40 × 3mm acryl plates sandwiching 5 spots of 2-mm diam. ¹⁴⁷Pm of 100 μCi), lot-IV a sponge tablet (18-mm diam. × 6 mm) with absorbed odorant oil (Table 1). While the vessel was drifting, the fishing rig was thrown overboard through the slipway at the speed of 0.5 m/s. The vessel might drift off to leeward and after setting, the traps and the sinker with wire might act as an anchor. Due to unfavorable weather, we could not recognize whether the traps were laid down on the sea floor, after paying out the entire 10, 490m. We wound up the wire at the speed of 0.5 m/s while drifting, and pulled in the traps by a stern winch. Between the start of paying out (27th, 14: 45) and the finish of hauling in (28th, 05 : 02), we supposed that about 6, 000 m of wire was laid down and the traps were set on the sea floor for 8 hours (Fig. 2, Table 2). Although the operation was incomplete, we could collect 3. 3 kg specimens of rare crabs, new tooth shells, an abyssal cutthroat, a cusk eel and the catch rate was 0.09 kg/trap, 0.5 individual/trap (Table 4,5). We could not recognize any difference in the catch with the difference in bait and netting. Chionoecetes angulatus RATHBUN 1924 (XII individuals) and Paralomis verrilli (BENEDICT) 1894 (I) were identified by M. TAKEDA, Dentalium sp. nov (II) by T. OKUTANI, Parabassogigas grandis (GÜNTHER) 1877 (I) and Histiobranchus bathybius (GUNTHER) 1877 (I) by A. HATTORI. Specimens of an Octopoda and of an Asterozoa have not been identified yet. Our next plan is to operate at 6, 200 m Site B: 30°N-147°E.

言語

書誌情報

ja : 東海区水産研究所研究報告
en : Bulletin of Tokai Regional Fisheries Research Laboratory

巻 108, p. 9-17, ページ数 9, 発行日 1982-11-30

出版者

東海区水産研究所

言語

出版者

Tokai Regional Fisheries Research Laboratory

言語

ISSN

収録物識別子タイプ

PISSN

収録物識別子

0040-8859

書誌レコードID

収録物識別子タイプ

NCID

収録物識別子

AN00156834

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識別子タイプ

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