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日本産マイワシの初期発育と産卵生態に関する研究
https://fra.repo.nii.ac.jp/records/2010857
https://fra.repo.nii.ac.jp/records/2010857a642cab2-d10a-46b8-bedc-35a567a06da0
| 名前 / ファイル | ライセンス | アクション |
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fra_k_22_87.pdf (8.2 MB)
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| Item type | 紀要論文 / Departmental Bulletin Paper(1) | |||||
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| 公開日 | 2024-10-02 | |||||
| タイトル | ||||||
| タイトル | 日本産マイワシの初期発育と産卵生態に関する研究 | |||||
| 言語 | ja | |||||
| タイトル | ||||||
| タイトル | Studies on Early Development and Spawning Ecology in Japanese Sardine Sardinops melanostictus | |||||
| 言語 | en | |||||
| 言語 | ||||||
| 言語 | jpn | |||||
| キーワード | ||||||
| 言語 | en | |||||
| 主題Scheme | Other | |||||
| 主題 | Japanese sardine; Sardinops melanostictus; early development; spawning ecology; egg abundance | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_6501 | |||||
| 資源タイプ | departmental bulletin paper | |||||
| アクセス権 | ||||||
| アクセス権 | open access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_abf2 | |||||
| 著者 |
松岡, 正信
× 松岡, 正信 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | In the most resource period and decrease one of Japanese sardine Sardinops melanostictus, the early development and spawning ecology of Western Kyushu population were investigated, from biological aspect. Artificial fertilization was undertaken, using adults caught by fishing on the research vessel. Successfully fertilized eggs started cleavage after one hour and five minutes of insemination. In three hours, eggs reached the morula stage and attained to the blastula stage in four hours. Hatching occurred within 30 to 36 hours. Unfortunately, all larvae died within 1.5 days after hatching , probably because of the deterioration of the rearing sea water and high temperature. Wild eggs collected from adjoining areas of Nagasaki Harbor were incubated from AbBa stage at 7.3-26.7℃. At 7.3 and 10.8℃, total and viable hatching rates, survival rate at first-feeding stage and rate of first-feeding success were lower than at 13.8-21.0℃. At 23.5 ℃, these rates were lower than at 13.8-21.0℃, and no normal larvae and no feeding ones were observed at 26.7℃. Eggs were also incubated at salinities of 17.4-53.8. At salinities of 26.1-39.6, total and viable hatching rates were high, mostly over 90%. Viable hatching rate at salinity of 17.4 was considerably low. At salinities of 44.3 and 53.8, total and viable hatching rates were relatively low. Survival rate at first-feeding stage and rate of first-feeding success at salinities of 17.4, 44.3 and 53.8 were lower than at salinities of 26.1-39.6. Incubation and rearing experiments at temperature of 18℃ were undertaken, using wild eggs. Total length of just hatched larvae was 3.44 mm. Fourth day-old larvae after hatching （about 5.7 mm TL） began to eat S type rotifers. 17th day-old larvae reached 9.9 mm TL on the average （range 8.50-11.95 mm）, and the rudiments of the dorsal and caudal fin rays and fin-supports were partly formed. 29th day-old larvae reached 15.37 mm TL（maximum, 20.0 mm）. In groups deprived of food from first-feeding stage, eighth day-old, 12th day-old and 17th day-old after hatching, most larvae could not take rotifers which were given on after three or four days. Developmental process of all cartilages and bones was described, using artificially raised and wild specimens. Changes in feeding and swimming functions were clarified from osteological side, and a developmental step forming four periods and eight phases was prescribed. Differential sequence of red muscle, pink muscle, white muscle and tonic-like fibers in the lateral muscle as an important locomotor organ was investigated. A layer of red muscle fibers was functionally developed at first-feeding stage. Beyond about 20 mm SL, stratification of red fibers, differentiation of tonic-like fibers and mosaic appearance of white fibers occurred. By 30 mm SL, pink fibers and two types of tonic-like fibers were differentiated. The structure of lateral muscle in a 37 mm SL juvenile was complete. Formative process of eye, olfactory organ, taste buds, lateral line system and inner ear was examined. The visual cell layer consisted of only single cones at first-feeding stage. In a 20.9 mm SL larva, rod-like cells and twin cones appeared. Both ciliated and microvillous receptor cells in olfactory organ were found shortly after hatching. Formation of olfactory nostrils and lamellae began at about 20 mm SL. Taste buds first appeared at 11.2 mm NL. Newly hatched larvae were equipped with 12 pairs of neuromasts on the head and trunk. The formation of head lateral line canal commenced at about 20 mm SL and four canals had ossified by 32.5 mm SL. Three semicircular canals formed by first-feeding stage. The structure of inner ear was entirely formed by 32 mm SL. The most spawning period was in March and the most GSI rate of females was over 20. From the ratio of specimens with hydrated eggs or postovulatory follicles at the regressing stage 0 （spawning day）, presumptive example of the average spawning interval was calculated to be from 4 to 6 days. Spawning time and duration of egg development of this species and Japanese anchovy Engraulis japonicus were investigated by 46 time vertical net samplings in the waters off southern Kyushu. Spawning of sardine occurred mainly at about 20:00 on 12 March and during 19:00-20:00 on 13 March, 1991. On the other hand, spawning of anchovy seemed to occur mainly during 00:00-01:00. Spawning times of both species were not overlapped at all. The vertical distribution of sardine eggs was investigated to clarify their spawning depth. Horizontal net tows were simultaneously conducted at five layers of approximately 1 m, 20 m, 40 m, 60 m and 80 m. AA stage eggs （from fertilization to beginning of enlargement of perivitelline space） were mostly collected at 40 m and 60 m depths. This means that the spawning depth was approximately 40-60 m. The spawning depth of Japanese anchovy was considered to be 0-20 m. The spawning depths of both species were not overlapped, also the spawning time. Morphological changes of unfertilized and fertilized sardine eggs were observed continuously. Unfertilized eggs could be divided into three types on the bases of their morphology: a distorted type, a narrow perivitelline-space type and a normal perivitelline-space type. The first type of eggs disintegrated and sank to the bottom of the containers in a short time. The latter two types of eggs formed not only a perivitelline space but also a blastodisc. They disintegrated gradually within 12 hours after stripping. Common to eggs of these three types, the egg membrane finally broke and the eggs contents were mainly lost. The examination of the field-collected eggs shows that some wild eggs were very similar in their morphological characteristics to unfertilized and disintegrated sardine eggs mentioned above. These facts suggest that unfertilized sardine eggs may be commonly present in natural spawning, especially in the area of the south from Kyushu. Short term （from 1 hour to 1 week） variations at the 9 stations in the number of collected sardine eggs were investigated in the adjoining area of Nagasaki Harbor. The maximum variations within 0.5 day were 2.3 or 6.6 times. The maximum variations between days were 2.0 or 5.1 times. The maximum variation at 9 stations was 33.8 times. This result indicates that the number of sardine eggs collected by plankton net changes considerably during short time periods and between adjacent stations, and that the total egg production calculated from spawning survey data may include wide variations. Egg abundance and distributional changes of sardine were studied in the waters around Kyushu from 1979 to 1995. A total 13,138 tows was undertaken for collecting eggs by six prefectural experimental stations and the Seikai National Fisheries Research Institute. The egg abundance was calculated for each 30́ × 30́ square and grouped into three large areas from north to south （AreasⅠ（north of 34˚N）, Ⅱ（34˚-31˚30́ N）, Ⅲ（south of 31˚30́ N））. The total egg number considerably fluctuated from 47×1012 in 1995 to 2,873×1012 in 1987. The fluctuation mainly occurred in AreaⅢ．The egg abundance of this area drastically decreased from 1991, and was only 0.3×1012 in 1995. The spawning month showed secular change. In AreaⅠ, spawning occurred mainly in March in 1979 and 1989, April in 1981-1983, and May in 1984-1987. Spawning after 1988 has occurred in March and April. The main spawning grounds were located in AreaⅠ and AreaⅡ in 1979 and 1980. After 1981, the main spawning grounds gradually shifted to the south, and in 1987 most of the spawning occurred in AreaⅢ. The spawning temperature changed with the shift of the spawning area. In 1979, eggs were spawned in 13-19℃, although spawning occurred at the 21℃ level in 1987. After 1991, the spawning temperature returned to 14-19℃. Although the sardine resource is very low in present, from past events on records, I may presume that it will increase to the maximum size after present to scores of years. | |||||
| 言語 | en | |||||
| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | 資源最大期から減少期における九州周辺海域のマイワシの初期発育過程と産卵生態について，生物学的側面から調査・研究した。調査船上で人工受精を行い，ふ化後1.5日まで飼育し，観察した。天然卵を用いた実験では，全ふ化率，正常ふ化率，摂餌開始期生残率および摂餌率は10.8℃以下および23.5℃以上ではこれらが低下し，明らかに悪影響が認められた。塩分濃度は17.4区では，正常ふ化率が極めて低かった。ふ化直後の仔魚は全長（TL）3.44 mm であった。ふ化後4日目（約5.7 mm TL）には摂餌開始期に達し，S 型シオミズツボワムシを捕食した。17日目に平均9.87 mm TL，29日目に15.37 mm TL（最大20.0 mm TL）となった。絶食条件下においたものでは，3～4日で瀕死状態となった。人工飼育魚と天然魚のシリーズ標本を用いて，全ての軟骨と硬骨の発達過程を記載した。それを基にして，骨格系の発達過程からみた摂餌・遊泳機能の発達を明らかにすると共に，4期8相から成る発育段階を区分した。重要な運動器官である体側筋について，赤色筋，桃色筋，白色筋および tonic-like fibers の発達過程を調べた。感覚器官の内，眼，嗅覚器，味蕾，側線器官および内耳の発達過程を調べた。体側筋系および感覚器官系の発達過程を基に，仔稚魚の生残に最も重要と考えられる摂餌・遊泳機能について骨格系を含めて総合的に検討した。また，発育段階についても，単なる区分ではなく発育の変化の集積として総合的に検討した。産卵盛期は3月で，雌の GSI の最大値は20以上であった。吸水卵または産卵当日の排卵後濾胞を持つ個体の割合から算出される本種の産卵周期は4～6日と推定された。ネット曳網の結果，本種の産卵時刻は20時前後であった。また，同時に採集されたカタクチイワシ卵の分析の結果，両種の産卵時間帯は全く重複しなかった。産卵後間もない卵割前の AA 卵は水深40～60 m で多く採集された。また，カタクチイワシの産卵中心は水深0～20 m であった。卵の発育過程を観察したところ，未受精卵でも囲卵腔が発達して胚盤を形成するものが認められた。これらは後に内部が崩壊して沈降した。薩南海域における産卵調査でもこのような卵が多数採集されたことから，天然海域でも多くの未受精卵が存在するものと推察された。9定点において，1時間～1週間程度の間の採集卵数の短期変動を調べた結果，大きな変動が認められた。1979～1995年の九州周辺海域におけるマイワシの産卵量と卵分布について調べた。産卵量の最低値は1995年の47兆粒，最大値は1987年の2,873兆粒であった。資源の水準により産卵期がずれる傾向があった。また，資源が低水準の時には九州西海域から山陰西部が産卵場となり，高水準の時には薩南海域が主産卵場となることが示された。産卵場の変化に伴い産卵水温も変化することが示された。現在，本種の資源水準はごく低位であるが，資源変動機構を解明するために基礎的研究の継承が必要であろう。 | |||||
| 言語 | ja | |||||
| 書誌情報 |
ja : 水産総合研究センター研究報告 en : Bulletin of Fisheries Research Agency 巻 22, p. 87-183, ページ数 97, 発行日 2008-02 |
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| 出版者 | ||||||
| 出版者 | 水産総合研究センター | |||||
| 言語 | ja | |||||
| ISSN | ||||||
| 収録物識別子タイプ | PISSN | |||||
| 収録物識別子 | 1346-9894 | |||||
| 書誌レコードID | ||||||
| 収録物識別子タイプ | NCID | |||||
| 収録物識別子 | AA11589591 | |||||
| 情報源 | ||||||
| 識別子タイプ | Local | |||||
| 関連識別子 | fra_k_22_87 | |||||
| 関連サイト | ||||||
| 識別子タイプ | URI | |||||
| 関連識別子 | https://agriknowledge.affrc.go.jp/RN/2010751350 | |||||
| 関連名称 | 日本農学文献記事索引（AgriKnowledge） | |||||
| 著者版フラグ | ||||||
| 出版タイプ | VoR | |||||
| 出版タイプResource | http://purl.org/coar/version/c_970fb48d4fbd8a85 | |||||
