説明
Information on oceanic migrations and spawning areas of tropical Pacific freshwater eels (genus Anguilla) is very limited. Lake Letas and its single outflowing river, Mbe Solomul on Gaua Island, Vanuatu, were surveyed for large migrating individuals. Twenty-four Anguilla marmorata (87 to 142 cm), 39 A. megastoma (50 to 131 cm), and 3 A. obscura (119 to 126 cm) were caught. Seven individuals were tagged with pop-up satellite transmitters and released offshore. One A. marmorata migrated 843 km towards the South Equatorial Current. The tag surfaced only 330 km from the point where the smallest leptocephalus has been captured so far. Tags on A. megastoma and A. obscura popped up within the archipelago.
データ レコード
この sampling event リソース内のデータは、1 つまたは複数のデータ テーブルとして生物多様性データを共有するための標準化された形式であるダーウィン コア アーカイブ (DwC-A) として公開されています。 コア データ テーブルには、6 レコードが含まれています。
拡張データ テーブルは2 件存在しています。拡張レコードは、コアのレコードについての追加情報を提供するものです。 各拡張データ テーブル内のレコード数を以下に示します。
この IPT はデータをアーカイブし、データ リポジトリとして機能します。データとリソースのメタデータは、 ダウンロード セクションからダウンロードできます。 バージョン テーブルから公開可能な他のバージョンを閲覧でき、リソースに加えられた変更を知ることができます。
バージョン
次の表は、公にアクセス可能な公開バージョンのリソースのみ表示しています。
引用方法
研究者はこの研究内容を以下のように引用する必要があります。:
Schabetsberger R, Økland F, Aarestrup K, Kalfatak D, Sichrowsky U, Tambets M, Dall’Olmo G, Kaiser R, Miller P I (2024). Oceanic migration of tropical Pacific eels from Vanuatu. Version 1.0. Southwestern Pacific Ocean Biogeographic Information System (OBIS) Node. Samplingevent dataset. https://nzobisipt.niwa.co.nz/resource?r=vanuatu_eels&v=1.0
権利
研究者は権利に関する下記ステートメントを尊重する必要があります。:
パブリッシャーとライセンス保持者権利者は Southwestern Pacific Ocean Biogeographic Information System (OBIS) Node。 This work is licensed under a Creative Commons Attribution (CC-BY 4.0) License.
GBIF登録
このリソースをはGBIF と登録されており GBIF UUID: 58eada0b-0178-454a-a823-45205d42f9fdが割り当てられています。 Ocean Biodiversity Information System によって承認されたデータ パブリッシャーとして GBIF に登録されているSouthwestern Pacific Ocean Biogeographic Information System (OBIS) Node が、このリソースをパブリッシュしました。
キーワード
Samplingevent
連絡先
- メタデータ提供者 ●
- 最初のデータ採集者 ●
- 連絡先
- 最初のデータ採集者
- 最初のデータ採集者
- 最初のデータ採集者
- 最初のデータ採集者
- 最初のデータ採集者
- 最初のデータ採集者
- 最初のデータ採集者
- 最初のデータ採集者
地理的範囲
Vanuatu and surrounding ocean
| 座標（緯度経度） | 南 西 [-15.717, 166.587], 北 東 [-8.77, 173.016] |
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生物分類学的範囲
Eels, genus Anguilla
| Species | Anguilla marmorata, Anguilla megastoma, Anguilla obscura |
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時間的範囲
| 開始日 / 終了日 | 2012-02-02 / 2012-05-02 |
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収集方法
Between 17 January and 2 February 2012, Lake Letas and its outflow were surveyed for silver eels by electrofishing, hooks, hook and line, and fyke nets in collaboration with fishermen from Gaua. The research team (R. Schabetsberger, F. Økland D. Kalfatak, U. Sichrowsky, M. Tambets) then anaesthetized, photographed, and measured the fish before they were either released (17 including tagged fish) or sacrificed (49) and given to local families.
| Study Extent | Gaua Island (Banks Group, Vanuatu) is the emerged top of a 3000 m high and 40 km wide stratovolcano. The symmetrical cone of approx. 25 km diameter is truncated between 500 and 690 m altitude by an 8.5 × 6 km central caldera. Its active volcano Mt. Garet (979 m a.s.l., 350 m high, base 3 km) towers over the crescent-shaped Lake Letas (100 m depth, 7 × 2 km, 418 m a.s.l.), which is constantly fertilized by the inflow of nutrient-rich, warm volcanic springs. Oxygen is available all the way to the deepest point (100 m), and abundant invertebrate life provides rich food resources (Schabetsberger unpubl. obs.). Migrating eels leave the lake through the outflowing Mbe Solomul River. It falls over a 120 m high cascade (Siri Falls) and bifurcates into 1 larger (18 m3 s−1) and 2 smaller rivers (0.9 and 6.1 m3 s−1) before entering the sea. Flow rates increase significantly during heavy rain. According to the experience of local fishermen, eels predominantly leave Lake Letas during heavy rains and north-westerly winds between January and March but may emigrate throughout the year. A tropical depression hitting the island on 24 January 2012 yielded silvering eels in the lower stretches of the flooding river several days later. |
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Method step description:
- Total length, distance from lower jaw to anus, to dorsal fin, and to gill opening, as well as length of mouth and length of pectoral fin were measured with a measuring tape to the nearest mm. Horizontal and vertical eye diameter was measured to the nearest 0.1 mm with ruler callipers. Weight measurements were taken on a Voltcraft HS-30 balance to the nearest 10 g. All eel species were determined through analysis of body proportions and dentition of the upper jaw (Ege 1939, p. 248–251). Colouration of the total body and the relative size of the eyes (Okamura et al. 2007) were used to classify silver eels. The stomachs of 7 Anguilla marmorata (4 yellow/3 silver) and 13 A. mega stoma (9/4) were opened and checked for contents.
- During the last 3 days of fishing operations, 7 eels with a silvery appearance (1 Anguilla marmorata, 4 A. megastoma, 2 A. obscura) were caught for tagging by local fishermen at the banks of the main river below Siri Falls, where fish are frequently found in shallow water after plummeting over the cascade. The single A. marmorata was caught near the mouth of the river. The tags were put on 3 different species, because we were unable to catch enough silver eels of the original target species A. megastoma. Due to the strong current that prevented the use of other fishing gear, the animals were pulled out from littoral hiding places with metal hooks mounted on wooden poles and pushed into hand-nets, resulting in minor skin lesions (ca. 1 cm) behind the anus. The small wounds were not treated with antibiotics, nor were they sutured to avoid the inclusion of anaerobic germs (F. Økland pers. obs.).
- After measuring, 2 types of satellite pop-up transmitters were deployed. Two eels were tagged with Mini-Pats (Wildlife Computers, Type 1), and the remaining 5 individuals, with X-tags (Microwave Telemetry, Type 2). Type 1 tags were provided for free by the manufacturer, and Type 2 tags were refurbished with new batteries after use in a previous project. The Type 1 tag is 11.5 cm long (excluding antenna), 40 mm wide and weighs 53 g in air. The Type 2 tag measures 12 cm in length, is 32 mm wide, and weighs 42 g.
- The tags were pre-programmed to surface after 3 mo assuming that the eels spawn north of Fiji and migrate with a speed of approximately 15 km d−1, based on the discovery of leptocephali east of Gaua (Kuroki et al. 2008) and the migration speed of similar-sized Anguilla dieffenbachii (Jellyman & Tsukamoto 2002). In case of premature death of the host or detachment of the tag, the transmitters were programmed to initiate a failsafe release mechanism, ascend to the surface, and transmit data. A depth reading deeper than 2100 m (pressure transducer sensor range exceeded) or 4 d of equal depth readings (±10 m) would initiate this mechanism.
書誌情報の引用
- Schabetsberger, R., Økland, F., Aarestrup, K., Kalfatak, D., Sichrowsky, U., Tambets, M., Dall’Olmo, G., Kaiser, R. and Miller, P.I., 2013. Oceanic migration behaviour of tropical Pacific eels from Vanuatu. Marine Ecology Progress Series, 475, pp.177-190.
追加のメタデータ
marine, harvested by iOBIS