著者

上原 匡人 太田 格 海老沢 明彦 立原 一憲

出版者

一般社団法人 日本魚類学会

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

2021

---

<p>Two closely related, commercially important threadfin breams, <i>Nemipterus furcosus</i> and <i>N. peronii</i>, are an essential coastal fishery resource in Okinawa Prefecture. The age, growth, reproductive cycle, and stomach contents from 124 <i>N. furcosus</i> and 37 <i>N. peronii</i>, obtained from November 2011 to December 2015, were examined, age being assessed from sectioned otoliths and gonadal histology. <i>Nemipterus furcosus</i> and <i>N. peronii</i> were the most abundant threadfin breams in Kin Bay and Nakagusuku Bay, Okinawa Island, areas including many coastal tidal flats, where the two species comprised 98.1% of the total number of <i>Nemipterus</i> individuals examined. Overall sex ratios of both species were significantly sex-biased, the apparent lack of transitional gonads implying functional gonochorism. The spawning seasons of both species were estimated as occurring between spring and fall, no immature fishes having been obtained. Age validation using edge-type analyses implied that opaque zones were formed once per year, being valid annual growth increments. Although no intersex differences in maximum length, growth equation, and age range were observed in <i>N. furcosus</i>, <i>N. peronii</i> females were larger and older than males. The greatest ages observed were 4.3 and 7.0 years for <i>N. furcosus</i> and <i>N. peronii</i>, respectively. Both species fed predominantly on crabs, which primarily occupied the inner bays. Over the previous 27 years, the catch per unit effort of <i>Nemipterus</i> has declined in the highly altered environments of Kin and Nakagusuku Bays, suggesting that the decline in the populations of these species at Okinawa Island may be due to coastal fishery practices, environmental decline, and the degradation of suitable habitats. The biological implications for conservation are discussed.</p>

著者

福地 伊芙映 堀部 翔 立原 一憲

出版者

国立大学法人 鹿児島大学総合研究博物館

雑誌

Ichthy, Natural History of Fishes of Japan

巻号頁・発行日

vol.7, pp.15-22, 2021

著者

和田 英敏 福地 伊芙映 宮本 圭 立原 一憲 本村 浩之

出版者

日本動物分類学会

雑誌

タクサ:日本動物分類学会誌 (ISSN:13422367)

巻号頁・発行日

vol.49, pp.67-73, 2020

---

<p>Two specimens (67.5–75.1 mm standard length; SL) of <i>Plectranthias maekawa</i> Wada, Senou and Motomura 2018 (Serranidae: Anthiadinae), previously recorded only the Tokara Islands, Kagoshima Prefecture, Japan, were collected from Okinawa-jima and Yonaguni-jima islands, Okinawa Prefecture, Japan. The present specimens, described herein in detail, represent the first records of the species from Okinawa Prefecture. Although the body depth (% of SL) has been regarded as one of diagnostic characters between <i>P</i>. <i>maekawa</i> and two closely-related congeners (<i>Plectranthias helenae</i> Randall, 1980 and <i>Plectranthias wheeleri</i> Randall, 1980) in the original description of <i>P</i>. <i>maekawa</i>, that of the present new specimens was overlapped with the latter two species (viz., 33.5–37.7% of SL in <i>P</i>. <i>maekawa</i>, 35.5–38.7% SL in <i>P</i>. <i>helenae</i>, and 35.6–37.9% of SL in <i>P</i>. <i>wheeleri</i>). The number of serration on the margins of subopercle and interopercle in <i>P</i>. <i>wheeleri</i> and <i>P</i>. <i>maekawa</i> has also been regarded as a diagnostic character for the two species, but additional specimens described in this study showed that the number of serration changed ontogenetically, and it overlapped in the similar-sized specimens of the two species. However, the validities of other diagnostic characters given in the original description of <i>P</i>. <i>maekawa</i> are reconfirmed in this study (viz., number of pectoral-fin rays, scales on above and below lateral line, morphometrics of body width, head length, third dorsal-fin spine length, caudal-peduncle length and depth, and both coloration of fresh and preserved conditions). In addition, three specimens of <i>P</i>. <i>wheeleri</i> (71.3–83.7 mm SL) from the Okinawa Islands, are reported here as the first records of the species from Okinawa Prefecture; it has been previously recorded from Japan (Sagami Bay, and Tokara and Amami islands), Taiwan, Indonesia, and Australasia.</p>

著者

中村 潤平 福地 伊芙映 立原 一憲 本村 浩之

出版者

一般社団法人 日本魚類学会

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

vol.67, no.1, pp.123-128, 2020

---

<p>Two specimens (227.8–251.7 mm standard length) of the rare grouper <i>Cephalopholis polleni</i> (Bleeker, 1868) were collected off Okinawa-jima and Ishigaki-jima islands, Ryukyu Islands, the species having previously been known from scattered insular localities in the Indo-Pacific Ocean, including the Ryukyu Islands between the Amami and Yaeyama Islands. Although a single specimen of <i>C. polleni</i> had been previously obtained from a fish market in Naha, Okinawa-jima Island, its capture locality was unknown and the specimen is now apparently lost. All other Japanese records of the species were based solely on photographs. Accordingly, the present specimens of <i>C. polleni</i>, described here in detail, from Okinawa-jima and Ishigaki-jima islands represent important specimen-based records of the species from Japan, being the first with precise locality data. A review of previous distribution records of <i>C. polleni</i> from Japanese waters is also provided.</p>

著者

中村 潤平 福地 伊芙映 立原 一憲 本村 浩之

出版者

一般社団法人 日本魚類学会

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

2020

---

<p>Two specimens (227.8–251.7 mm standard length) of the rare grouper <i>Cephalopholis polleni</i> (Bleeker, 1868) were collected off Okinawa-jima and Ishigaki-jima islands, Ryukyu Islands, the species having previously been known from scattered insular localities in the Indo-Pacific Ocean, including the Ryukyu Islands between the Amami and Yaeyama Islands. Although a single specimen of <i>C. polleni</i> had been previously obtained from a fish market in Naha, Okinawa-jima Island, its capture locality was unknown and the specimen is now apparently lost. All other Japanese records of the species were based solely on photographs. Accordingly, the present specimens of <i>C. polleni</i>, described here in detail, from Okinawa-jima and Ishigaki-jima islands represent important specimen-based records of the species from Japan, being the first with precise locality data. A review of previous distribution records of <i>C. polleni</i> from Japanese waters is also provided.</p>

著者

國島 大河 立原 一憲

出版者

一般社団法人 日本魚類学会

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

vol.66, no.2, pp.161-170, 2019

---

<p>The species of <i>Mugilogobius</i> sp. (Japanese name: Izumi-haze) and <i>M. chulae</i> are both common species, sympatrically inhabiting the estuaries and tidal flats of Okinawajima Island. Some species of <i>Mugilogobius</i> has a urea cycle, and their processing ability is higher, especially in northern distributed species, such as <i>M. abei</i> and <i>Mugilogobius</i> sp. It is possible to differentiate their life history traits and habitats on the basis of urea processing ability. However, because little is known in detail of their life history and habitat, <i>Mugilogobius</i> sp. and <i>M. chulae</i> were investigated through monthly sampling conducted on the southern part of the Sashiki Tidal flat and Manko Wetland on Okinawa-jima Island, from January 2012 to January 2013. The spawning seasons of <i>Mugilogobius</i> sp. and <i>M. chulae</i> are from January to October and April to October, respectively, with peaks in the summer period (April to October), indicating that maturity in both species is closely related to changes in water temperature. A comparison with the spawning season of <i>M. abei</i>, a temperate region species, revealed the subtropical species to spawn over a longer period. Estimates of daily age from otolith analyses indicated the possibility of recruitment from other areas, since histological observations revealed mismatches of gonads and birthmonths between different spawning seasons, as estimated by back-calculations of daily age. The longevity of <i>Mugilogobius</i> species was about six months. The study also revealed the growth rate of <i>Mugilogobius</i> sp. to be similar to that of <i>M. chulae</i>. <i>Mugilogobius chulae</i> locally inhabited mangrove habitats, whereas <i>Mugilogobius</i> sp. showed wide habitat use and was less susceptible to decreasing habitat than the former. Accordingly, future conservation of <i>M. chulae</i> is dependent upon suitable mud habitat associated with mangroves.</p>

著者

國島 大河 立原 一憲

出版者

一般社団法人 日本魚類学会

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

2019

---

<p>The species of <i>Mugilogobius</i> sp. (Japanese name: Izumi-haze) and <i>M. chulae</i> are both common species, sympatrically inhabiting the estuaries and tidal flats of Okinawajima Island. Some species of <i>Mugilogobius</i> has a urea cycle, and their processing ability is higher, especially in northern distributed species, such as <i>M. abei</i> and <i>Mugilogobius</i> sp. It is possible to differentiate their life history traits and habitats on the basis of urea processing ability. However, because little is known in detail of their life history and habitat, <i>Mugilogobius</i> sp. and <i>M. chulae</i> were investigated through monthly sampling conducted on the southern part of the Sashiki Tidal flat and Manko Wetland on Okinawa-jima Island, from January 2012 to January 2013. The spawning seasons of <i>Mugilogobius</i> sp. and <i>M. chulae</i> are from January to October and April to October, respectively, with peaks in the summer period (April to October), indicating that maturity in both species is closely related to changes in water temperature. A comparison with the spawning season of <i>M. abei</i>, a temperate region species, revealed the subtropical species to spawn over a longer period. Estimates of daily age from otolith analyses indicated the possibility of recruitment from other areas, since histological observations revealed mismatches of gonads and birthmonths between different spawning seasons, as estimated by back-calculations of daily age. The longevity of <i>Mugilogobius</i> species was about six months. The study also revealed the growth rate of <i>Mugilogobius</i> sp. to be similar to that of <i>M. chulae</i>. <i>Mugilogobius chulae</i> locally inhabited mangrove habitats, whereas <i>Mugilogobius</i> sp. showed wide habitat use and was less susceptible to decreasing habitat than the former. Accordingly, future conservation of <i>M. chulae</i> is dependent upon suitable mud habitat associated with mangroves.</p>

著者

立原 一憲 四宮 明彦 木村 清朗 今井 貞彦

出版者

日本生態学会

雑誌

日本生態学会誌 (ISSN:00215007)

巻号頁・発行日

vol.38, no.2, pp.159-167, 1988-08-31

---

Observations on the development of aggressive behavior of Japanese perch, Coreoperca kawamebari, were made over a 1-year period. Newly hatched larvae aggregated at the water surface and showed no aggressive behavior. Several days after yolk sac absorption, larvae dispersed from the water surface to the substrate and began to feed and fight. Chasing and lateral displays as seen in adult fish were firstly observed at this time, and a dominance hierarchy was evident at 50 days after hatching. Dominant individuals formed their territories after 50 days and gradually enlarged them as body size increased. The behavioral ontogeny of this fish is divisible into four phases, i. e. aggregation, dispersion, developing of aggressive behavior and territorial phases, and these correspond with four different stages of growth, namely prelarva, postlarva, juvenile and young stages, respectively.

著者

石川 哲郎 高田 未来美 徳永 圭史 立原 一憲

出版者

日本生態学会

雑誌

保全生態学研究 (ISSN:13424327)

巻号頁・発行日

vol.18, no.1, pp.5-18, 2013-05-30

---

1996〜2011年に、沖縄島の266河川において、外来魚類の定着状況と分布パターンを詳細に調査した結果、13科に属する30種1雑種の外来魚類を確認した。このうち、温帯域から熱帯域を含む様々な地域を原産とする合計22種(国外外来種19種、国内外来種4種)が沖縄島の陸水域で繁殖していると判断され、外来魚類の種数は在来魚類(7種)の3倍以上に達していた。繁殖している外来魚類の種数は、20年前のデータと比較して2倍以上に増加していたが、これは1985年以降に18種もの観賞用魚類が相次いで野外へ遺棄され、うち10種が繁殖に成功したことが原因であると考えられた。外来魚類の分布は、各種の出現パターンから4グループに分けられた:極めて分布が広範な種(カワスズメOreochromis mossambicusおよびグッピーPoecilia reticulata)、分布が広範な種(カダヤシGambusia affinisなど4種)、分布が中程度の広さの種(マダラロリカリアPterygoplichthys disjunctivusなど5種)および分布が狭い種(ウォーキングキャットフィッシュClarias batrachusなど20種)。外来魚類の出現頻度と人口密度との間には正の相関が認められ、外来魚類の出現パターンと人間活動との間に密接な関係があることが示唆された。外来魚類は、導入から時間が経過するほど分布を拡大する傾向があったが、その速度は種ごとに異なっていた。特に、日本本土やヨーロッパにおいて極めて侵略的な外来魚類であると考えられているモツゴPseudorasbora parva、オオクチバスMicropterus salmoidesおよびブルーギルLepomis macrochirusの分布拡大が遅く、外来魚類の侵略性が導入された環境により異なることが示唆された。沖縄島の陸水域において新たな外来魚類の導入を阻止するためには、観賞用魚類の野外への遺棄を禁ずる法規制の整備と共に、生物多様性に対する外来生物の脅威について地域住民に啓発していくことが重要である。

著者

立原 一憲 Obara Emi

出版者

水産増殖談話会

雑誌

水産増殖 (ISSN:03714217)

巻号頁・発行日

vol.51, no.3, pp.295-306, 2003-09-20

---

カワスズメOreochromiss mossambicusは、1954年に沖縄島に移入された後、野外に逃げ出して定着し、現在では多くの河川で優占種となっている。ここでは本種の卵内発生の経過と飼育条件下における稚魚への成長に伴う外部形態および骨格系の発達を記載した。カワスズメ卵は、1997年6月4日に沖縄島の小那覇川で採集した口内保育中の親から得た。卵は平均長径2.72mm、平均短径1.96mmの楕円型で、受精後88時間30分で孵化した。孵化後6日、体長4.0mmで遊泳し始め、12日後に稚魚に達した。本種の骨格の主要な要素は、孵化後25日には全て形成された。