種々の成長段階の帆立貝の環境に対する抵抗性について : 特に鰓織毛運動に対する懸濁浮泥, 酸素欠乏などの影響
Nihon Seitai Gakkaishi
ON BEHAVIOR OF THE SCALLOP UNDER SOME ENVIRONMENTAL CONDITIONS, WITH SPECIAL REFERENCE TO EFFECTS OF SUSPENDED SILT, LACK OF SOLUBLE OXYGEN AND OTHERS ON CILIARY MOVEMENT OF GILL PIECES
Spawned larvae of the scal 星 oP , Pecten ye ・ ・soensiS ∫ AY , in Mutsu Bay, gdew to ebOUt 300 micra of shell length and were attached te the s ψ stratum i ' nearly June . These attached spats , which reach 〔 1 6 ・ 10mm in shelE Iength , turn to bottom life from late Jロ1y. Meanwhile , a high mortality , which h4s not been explained , of these spats was ascertained , such phenomenon was often obsemd during sum ・ mer and early autum 叫 and the ' mortality decrClase ( l i皿 November when the spats
... ained from 30 to 40mm in sheU length . In this paper the behaviofs l of the scalloP6 in var 韋 ous stages of growth were observed under some env 三 ronmental conditions which were of ecological impOrtanee. Gill pieces of 3 × 5mm were cut from t配 gill lame旺a of the 鵬 1且 o卿 nd immersed in sea water , then they crawled on the bl}ttom of the containers , Petri dishes . Thg vel ity of the crawl was measured a 口d the τelative velocity was esti − rnated in cornpalrison with that of the control ones . The results are as follows : 1. CHiary activity of gi豆 1 pieces was decreased considerably by a sman amo 阻 t of suspended sik , especially in the 5Fou scaliop ( Fig.1) . 2. By low tension of soluble oxygen the ciIiary activity of yeung scallepO was s ckened to 15 − 28 per cent after fifteen minutes and 「 the gill piece crawling al 祀 ady stopped at abOut 20 minutes ( Table 1 ) 。 3、 Small pieces of the gi 匡 l were iPPropriately stained with each of vital staining dyes, and then encl 〔 ) seti together with a smalL amo 皿 t of sea water , in a s1na11 respiratory chambe 重o駐 the s 且 ide glass a珮dobse「v ( Xi under the 皿 icroscope . By this methOd the critical intracellular redexpotential limiti dliary activity could be determined ( Table 2) . Young s侃 110p s齢 of 11 − 18 mm in she 旧 ength remained in a hig4 rH value a ロd from these facts it was 正 nferred that they have net yet deyeloped agreater tOlerance tO anaerobic cOnditions ・ 4. Relative ▽ el ity of scalloP gin Pi es in va 「ying sea water co 皿cen と rations showed that the scaHop was a stenohaline a 皿 imalg especially it was so in the young , and a higher $ Peed was observed in the concentrated sea water of 2L49 Cl % ( 38. 172 819S % ) than in normal sea water of 18. 11 Cl % ( 32. 719S % ) ( Fig.2). 5・ Crawli velocity of gi 且 l pieces w 駆 ich were transferred suddenly from ff er 20°C to varying temperatures was d reased , e5P ially in you scallops the crawli WaS stopped by the change of 15℃ , i. e . from 20°to 5℃ ( Tab 夏 e 3 ) . 6. From the facts obtai 龍ed , the abeve ・ mentioned high mor . tality of the spats may be induced by the suspended silt and a 且 ow tension of soluble oxygen caused by the oxidation of organic matter in bOttom mud , water stratificatien of summer calming , circu − latien in early iuturnn dr〔幻 gi Gf bottom丘shery etc. In ( 瓦 tober and Nevember the you scallop might have developed a greater to蓋 eran to such environmental cha es.