デラウェア湾におけるサンドタイガーシャークと大西洋チョウザメの社会性を検証するUDの研究 UD study examines the sociality of sand tiger sharks and Atlantic sturgeon in the Delaware Bay
2022-10-05 デラウェア大学 (UD)
A new study by the University of Delaware shows that sand tiger sharks in the Delaware Bay also tend to travel in cliques whereas Atlantic sturgeon do not. This photo was taken by Tanya Houppermans of Blue Imaging and Exploration and shows sand tiger sharks in North Carolina.
音響テレメトリーデータは、特定のエリア(この場合はデラウェア湾)にある音響受信機の配列の中に、動物にトランスポンダーを設置することで収集される。魚が泳いでくると、トランスポンダーがレシーバーに信号を送り、魚の位置と身分を明らかにする。
大西洋チョウザメの場合は社会性のなさが明らかになった。
大西洋チョウザメが集団を形成している証拠は何もないことがわかった。
サンドタイガーシャークについては、逆の効果が示されました。優先的・回避的な付き合い、徒党の形成がしっかりと証明されているのだ。興味深いことに、彼らは性別によるグループ分けをしなかった。
<関連情報>
- https://www.udel.edu/udaily/2022/october/social-sand-tiger-sharks-atlantic-sturgeon/
- https://www.sciencedirect.com/science/article/abs/pii/S0003347222002287?dgcid=author
河口環境における大西洋チョウザメとサンドタイガーシャークの社会性 The sociality of Atlantic sturgeon and sand tiger sharks in estuarine environment
Robert Roose,Matthew Oliver,Danielle Haulsee,Matthew Breece,Aaron Carlisle,Dewayne Fox
Journal of Animal Behaviour Available online: 20 September 2022.
DOI:https://doi.org/10.1016/j.anbehav.2022.08.008
Highlights
- •We analysed sociality of Atlantic sturgeon and sand tiger sharks in Delaware Bay.
- •Sand tigers exhibited preferential co-occurrence, modularity and maturity assortment.
- •Atlantic sturgeon exhibited little sign of sociality.
- •Sand tigers and Atlantic sturgeon preferentially assorted by species.
- •Environmental variables may influence network formation in short time windows.
Social network analyses are used by ecologists to examine the various drivers of animal social structures. While social behaviours are found throughout the animal kingdom, their roles in structuring marine communities are poorly understood. Comparisons of sociality across marine fishes in the same location and time are rare. A large acoustic telemetry network in Delaware Bay allowed us to analyse the sociality of Atlantic sturgeon, Acipenser oxyrinchus oxyrinchus, and sand tiger sharks, Carcharias taurus. Both species co-occur in the bay, are long-lived, make seasonal migrations and aggregate for unknown reasons. However, these species occupy distinctly different trophic positions and ecological niches. We found little evidence for sociality among Atlantic sturgeon. However, sand tigers exhibited evidence for preferential co-occurrence, modularity and assortment by maturity. In addition, we found that these species preferentially associate with conspecifics. Our findings suggest that sand tigers exhibit a higher degree of sociality than Atlantic sturgeon while in the Delaware Bay. From these findings, we outline the social structures of two evolutionary distinct species while they co-occur in the Delaware Bay. Additionally, we explored the influence that environmental acoustic conditions have on social network metrics and make recommendations for future analyses using acoustic telemetry in estuarine environments.
