{"created":"2024-04-25T05:05:24.093854+00:00","id":2003260,"links":{},"metadata":{"_buckets":{"deposit":"7e4c25d4-410a-45e5-845d-216bc1470115"},"_deposit":{"created_by":10,"id":"2003260","owners":[10],"pid":{"revision_id":0,"type":"depid","value":"2003260"},"status":"published"},"_oai":{"id":"oai:fra.repo.nii.ac.jp:02003260","sets":["12:14:1716951205920"]},"author_link":["3354"],"control_number":"2003260","item_10002_biblio_info_7":{"attribute_name":"bibliographic_information","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"1985-10","bibliographicIssueDateType":"Issued"},"bibliographicNumberOfPages":"42","bibliographicPageEnd":"42","bibliographicPageStart":"1","bibliographicVolumeNumber":"19","bibliographic_titles":[{"bibliographic_title":"南西海区水産研究所研究報告","bibliographic_titleLang":"ja"},{"bibliographic_title":"Bulletin of the Nansei Regional Fisheries Research Laboratory","bibliographic_titleLang":"en"}]}]},"item_10002_description_5":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"Sepiella japonica SASAKI, Sepiidae, is one of the important fisheries resources in Japan. The Sepiella is distributed in the coastal waters of central and southern Japan, south and west coast of Korean Peninsula and East China Sea. In Japan, it has been found in Tokyo Bay, Mikawa Bay, the Seto Inland Sea, along the coasts of shikoku and Kyoushu and along the coast of the Sea of Japan to the west of Toyama Bay. About 70% of its catches in Japan is landed from the Seto Inland Sea. The author has investigated and elucidated the relationship between the growth and maturity of Sepiella japonica and its migration in the western part of the Seto Inland Sea and the adjacent waters of the Uwa Sea or Uwa Kai. Fisheries of Sepiella japonica In the Seto Inland Sea, some Spepiidae are caught by small trawlnets, ika pots; also called hoop nets and small set nets. Besides these fishing methods, there are gill nets, boat seines, surrounding nets and ika anglings. 88% of the landings of this cuttlefish come from catches by means of small trawlnets, ika pots and small set nets. The average catch (1978-1980) in the six fishing grounds from the innermost Inland Sea area (Hiuchi Nada) to the outer coast (Uwa Sea) indicates that the fishing season extends all the year round. The two main fishing seasons are in spring (May-June) and winter (December-February). The species is caught in the shallower fishing grounds of the Seto Inland Sea in spring and also caught in the Suo Nada to Iyo Nada and the Uwa Sea in autumn and winter. The annual landings of this species roes from the 5,000 ton level in 1975, to the level of 10,000 ton in 1978, but decreased sharply to the level of 3,000 ton by 1980. Growth Sepiella japonica is known to have a one year life span. The samples taken from 1979 to 1980 indicate that there is no difference in the mean body lengths of male and female (the shell length was taken as the body length). The young cuttlefish of about 20-65 mm in body length which appear in the shallow sea along the coast in September grow rapidly to be 30-110 mm by the time they begin to migrate to the deeper waters in October. They continue to migrate to wintering area in December reaching 70-140 mm in body length. Then the growth slows down attaining only 80-115 mm by June. The average body length of the samples caught in the spawning season is largest in April, becoming smaller as time passes. It is assumed that groups growing and maturing more rapidly start to migrate earlier to the spawning grounds. During April and June, the decreasing pattern in in viscera-arm-head weight excluding genital organs and mantle weight resembles closely to the tendency of body weight decrease in the samples of the same body lengths (100-130 mm). This may be due to the exhaustion of spawning. Also, deaths take place in large quantities immediately after the spawning season. From these facts, it is asumed that the life span of the species is one year. Relative growth In order to clarify the growth stages of the species, the following investigations have been carried out. 1) Relatioship between the body length and the body weight, the mantle weight, the shell weight and the liver weight. 2) Changes in the ratio of the mantle weight, the shell weight and the liver weight to the body weight in the course of growth. 3) Changes of condition factor in the course of growth. 4) Changes in the mantle width, the shell height, locular index and length of each arms (1st, 2nd, 3rd and 4th arm) in the course of growth. The principal changes in the body form and the measurements of the main parts of the body are found in cuttlefish with body lengths of 35, 75, 105 and 125 mm. Thus, the growth process can be devided into five stages; juvenile (20-35 mm), young-1st stage (35-75 mm), young-2nd stage (75-105 mm), adult-1st stage (105-125 mm) and adult-2nd stage (above 125 mm). Since the species has few morphological features in the course of development, the changes in relative growths mentioned above were examined collectively in order that the growth pattern and the period of spawning may be understood. Maturity On maturity, the following relationships were examined to elucidate the spawning season and the spawning pattern: Sex ratios, the relationship between egg diameter and maturity stage, quantity of eggs in the gonad during the spawning season, the seasonal changes of maturity factor of each sex, the relationship between the body length and the maturity factor in the spawnihg season. The monthly change of maturity factor show that the spawning season of this species is from April to July. The sex ratio was roughly 1:1 throughout the year. The survey of relationshipbetween the body length and maturity factor by months show that the primary change of  maturity factor occur in male with body lengths of 75 and 125 mm, and in female with body lengths of 120 and 130 mm. The ratio of the weight of nidamental's gland (which stores substances to make eggs adhere to the substrate at the time of spawning) to the body weight increases with the increment of body length when the body length reached the first and second growth stages of adult. The development of eggs become clearly discernible as the ovary develops: Immature eggs of less than 2mm in diameter, maturing eggs of 2-3mm and matured eggs of over 3mm. Spawning occurs many times, and 1,000-1,500 eggs are spawned in the first spawning. The shape of the newly spawned eggs are similar to chicken eggs having the size of 3.7-4.2 mm by 2.9-3.9mm. Migration The discussion on migration is based on the surveys of fishing ground for each growth stage and maturity ecology. These surveys are based on monthly body length composition from the samples obtained through the main fishing methods in the different fishing grounds. Results indicate that from April to July, large cuttlefish migrate from the deeper water to the shallower seas, then the smaller cuttlefish appear in the shallow areas in the coast. From autumn to winter, on the other hand, small cuttlefish migrate down to the deeper waters of the Uwa Sea and Iyo Nada from the bottomed area of the inner waters of the western part of the Seto Inland Sea. The results of the questionnaire survey on fishing methods, fishing grounds and fishing periods conducted at the various fisheries cooperative unions show that the migration from the wintering grounds to the spawning areas takes about three months. On the contrary, it takes three and a half months for small cuttlefish to migrate from the bottomed area of shallow seas to the deeper waters of wintering grounds. The relationship between the catch amount of spawning groups and that of wintering groups was examined to determined to the relationship between the amount of spawning adult and the young progeny resources. From this survey, it is assumed that there are close relationships between the wintering adults and the spawners which migrated up to the shallow seas and also bet ween young cuttlefish and the adult groups which migrated down to the deep wintering grounds. The conclusions drawn from these facts are as follows: Adult cuttlefish migrate from the deep sea of the west coast of Iyo Nada and the Uwa Sea to the shallow seas of the western part of the Seto Inland Sea for spawning. The reproductive maturation occur during the end of March and early April. Spawning begins in all spawning grounds from the end of April to early May. Distribution and Migration by Growth Stages Migration ecology by growth stages was elucidated collectively from the information on each environmental factor in fishing ground. 1) Spawning stage: The spawning season was from April to July with the full season from May to June in the shallow sea of the inlet. The water temperature at this time is 10.8-22.8°C and salinity was 30.60-33.40 ‰. As the eggs of this species are adhesive, an egg develops in the same environmental condition as in the spawning grounds. 2) Young-1st stage: Juveniles being hatched in the spawning grounds grow to 35 mm in body length reaching the first stage of youth. The distribution expands from the shallow waters to a little deeper area. The water temperature and salinity of the area are 23,2-27.8°C and 31.22-32.95‰. The species of this stage show greatest increment in body length and weight. The cuttlefish of this stage are caught by small set nets and small trawlnets. 3) Young-2nd stage : In this stage, the increment of body length slows down. Although gonad weight of both male and female are still very small, it is in this stage that the differences between male and female gonads become discernible. The water temperature was 15.5-23.6°C and salinity was 31.82-33.95 ‰ at the depth of 7-10m. In this stage, the cuttlefish are caught by small set nets and small trawlnets. 4) Adult-1st stage: The growth increment of this stage, which is 105-120 mm in body length, is smaller than the previous stage. The same can be said about the body weight. Testis develop and spermatophore appear in the spermatophoric sac. Gonad weight increase at the end of this stage and eggs mature constantly though matured eggs are not yet found in the oviduct. The wintering migration start at the beginning of this stage and cuttlefish reach the wintering ground at the end of the stage. The water temperature is 8.3-13.5°C and salinity is 32.68-34.15‰ at the depth of 30-40 m. The cuttlefish of this stage are caught by Ika trawlnets. 5) Adult-2nd stage: Cuttlefish of body length over 125mm show smallest growth rate. Gonad oviduct weight increase rapidly in this stage and matured eggs are found in the oviduct. Nidamental's gland weight also increase rapidly and is ready for spawning at the middle of this stage. The cuttlefish mature as the migration for spawning begins. The water temperature is 7.6-12.4 °C and salinity is 33.00-33.78 ‰ in the surrounding waters where cuttlefish of this stage migrate for spawning. The cuttlefish of this stage are caught by Ika trawlnets and Ika anglings. Also, the cuttlefish just before spawning are caught by small set nets and small trawlnets. On the spawning season, the cuttlefish in this latter course of growth further are caught by ika pots.","subitem_description_language":"en","subitem_description_type":"Abstract"},{"subitem_description":"西部瀬戸内海及び宇和海に分布するシリヤケイカについて,その成長·成熟過程と移動回遊生態との関係を明らかにした。シリヤケイカの漁業:西部瀬戸内海におけるシリャケイカの年間漁獲量(1980)の88%は小型底曳網,イカかご漁業及び小型定置網で漁獲されている。燧灘から宇和海に至る6水域では周年漁獲されるが,春季(4~7月)と秋~冬季(10~3月)が主漁期である。春季には内海の奥部各水域で多獲され,秋~冬季には周防灘~伊予灘及び宇和海で多獲される。1976~'80年の年間漁獲量は,1975年の5,000トン台から1978年の10,000トン台に増大し,翌々年には3,000トン台に激減した。成長:シリヤケイカは雌雄の体長に大差がない。本種の成長を月別にみると,9月に浅海沿岸域に体長20~65mmの稚·幼イカが出現し,その成長は極めて速い,沖合水域へ移動を始める10月には30~110mmに成長し,越冬場への移動終了期の12月までには,70~140mmに成長する。12月以降の成長は極めてゆるやかで,翌年春季の6月には80~155mmとなる。産卵期の体長は4月当初に大きく,月の経過に伴って小さくなる。このことは成長がよく,早く成熟した群から順次移動を起し産卵場へ来遊するものと考えられる。4~6月の産卵期においては,生殖器管重量を除いた腕~頭~内臓部重量及び外套重量の経時的減少が,体重の減少傾向に近似していることから,産卵期における体力の消耗の激しさが推察され,産卵期以降によく見られる多量斃死現象とから,本種の寿命は満1年と推定される。相対成長:体長に対する体重,外套重量,甲重量,肝臓重量の関係及び外套重量,甲重量,肝臓重量等の体重に対する割合の変化,肥満度の変化,甲幅,甲高,無輪帯率の変化,各腕長の変化等を解析し,体形及び体部位の主要な変化が,体長35mm,75mm,105mm,125mmに生じていることから,本種の発育過程は稚·幼イカ期(35mm>),若イカ1期(35~75mm),若イカ2期(75~105mm),成イカ1期(105~125mm),成イカ2期(125mm≤)の5期に区分される。成熟:本種の性比は,1年を通してみると概ね1:1である。生殖腺熟度指数の月別変化から,産卵期は4~7月と推定され産卵は何回かに分けて行われる。初回の産卵数は約1,000~1,500粒である。輸卵管から放出された直後の卵の形状は鶏卵に類似し,その長径は3.7~4.2mm,短径は2.9~3.9mmである。この卵は黒色を呈する。移動回遊:宇和海及び伊予灘西岸の沖合域で越冬し,2月下旬頃までに成長,成熟したイカは,3月下旬~4月上旬に越冬場から,西部瀬戸内海奥部の内湾性浅海域にむけて成熟の進んだイカから順次産卵のための移動を開始し,4月中旬には産卵場に分散的に回遊する。4月下旬から5月上旬にかけて各地産卵水城で産卵が始まる。6月中旬から8月中旬に孵化し,干瀉及びそれに続く浅海域で若イカに成長したイカは,その後急速に成長しながらさらに沖合の水域に移動する。成長の進んだ群から順次南下·越冬回遊を始め,12月上旬には伊予灘西岸の沖合域を経て,宇和海を中心とする豊後水道北部深部水域へと集積的に回遊する。発育段階別生息環境:産卵場である内湾性浅海域の水温は 10.8~22.8℃で, 塩分は30.60~33.40‰である。体長3~35mmの稚幼イカ期の生息域は,産卵場周辺の干瀉~砂泥域に限られ,その水温は14.3~28.9℃,塩分は31.22~32.95‰である。体長35~75mmに成長した若イカ1期のイカの生息域は,干瀉につづく浅海の沖合域であり,その水温は23.2~27.8℃,塩分は31.22~32.95‰である。体長75~105mmに相当する若イカ2期のイカの生息域の水深は7~10mであり,その水温は15.5~23.6℃,塩分は31.82~33.95‰である。成イカ1期つまり体長105~120mmに相当するイカに成長する頃から越冬回遊が始まり,この期の終期に越冬場に到達する。この生息域の水深は30~45mで,環境水温は8.30~13.50℃,塩分は32.68~34.15‰である。体長120~125mmの成イカ2期は,産卵回遊期に当り水温は7.60~12.40℃,塩分は33.00~33.78‰である。","subitem_description_language":"ja","subitem_description_type":"Abstract"}]},"item_10002_publisher_8":{"attribute_name":"出版者","attribute_value_mlt":[{"subitem_publisher":"南西海区水産研究所","subitem_publisher_language":"ja"},{"subitem_publisher":"Nansei Regional Fisheries Research 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カズオ","creatorNameLang":"ja-Kana","creatorNameType":"Personal"}],"familyNames":[{"familyName":"Ueda","familyNameLang":"en"},{"familyName":"上田","familyNameLang":"ja"},{"familyName":"ウエダ","familyNameLang":"ja-Kana"}],"givenNames":[{"givenName":"Kazuo","givenNameLang":"en"},{"givenName":"和夫","givenNameLang":"ja"},{"givenName":"カズオ","givenNameLang":"ja-Kana"}],"nameIdentifiers":[{"nameIdentifier":"3354","nameIdentifierScheme":"WEKO"}]}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"jpn"}]},"item_resource_type":{"attribute_name":"item_resource_type","attribute_value_mlt":[{"resourcetype":"departmental bulletin paper","resourceuri":"http://purl.org/coar/resource_type/c_6501"}]},"item_title":"シリヤケイカの成長，成熟及び移動生態に関する研究","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"シリヤケイカの成長，成熟及び移動生態に関する研究","subitem_title_language":"ja"},{"subitem_title":"Studies on the Growth, Maturation and Migration of the Shiriyake-ika, Sepiella japonica SASAKI.","subitem_title_language":"en"}]},"item_type_id":"10002","owner":"10","path":["1716951205920"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2024-04-25"},"publish_date":"2024-04-25","publish_status":"0","recid":"2003260","relation_version_is_last":true,"title":["シリヤケイカの成長，成熟及び移動生態に関する研究"],"weko_creator_id":"10","weko_shared_id":-1},"updated":"2025-04-17T06:18:11.070828+00:00"}