Haulsee Danielle E, Fox Dewayne A, Breece Matthew W, Brown Lori M, Kneebone Jeff, Skomal Gregory B, Oliver Matthew J
College of Earth, Ocean, and Environment, University of Delaware, Lewes, DE, 19958, USA.
Department of Natural Resources, Delaware State University, Dover, DE, 19901, USA.
Sci Rep. 2016 Sep 30;6:34087. doi: 10.1038/srep34087.
Complex social networks and behaviors are difficult to observe for free-living marine species, especially those that move great distances. Using implanted acoustic transceivers to study the inter- and intraspecific interactions of sand tiger sharks Carcharias taurus, we observed group behavior that has historically been associated with higher order mammals. We found evidence strongly suggestive of fission-fusion behavior, or changes in group size and composition of sand tigers, related to five behavioral modes (summering, south migration, community bottleneck, dispersal, north migration). Our study shows sexually dimorphic behavior during migration, in addition to presenting evidence of a potential solitary phase for these typically gregarious sharks. Sand tigers spent up to 95 consecutive and 335 cumulative hours together, with the strongest relationships occurring between males. Species that exhibit fission-fusion group dynamics pose a particularly challenging issue for conservation and management because changes in group size and composition affect population estimates and amplify anthropogenic impacts.
对于自由生活的海洋物种，尤其是那些远距离洄游的物种而言，复杂的社会网络和行为很难被观察到。通过植入声学收发器来研究沙虎鲨（Carcharias taurus）的种间和种内相互作用，我们观察到了一种历史上与高等哺乳动物相关的群体行为。我们发现有强有力的证据表明，沙虎鲨存在裂变融合行为，即群体大小和组成的变化，这与五种行为模式（夏栖、向南洄游、群体瓶颈、扩散、向北洄游）有关。我们的研究表明，在洄游过程中存在两性异形行为，此外还提供了证据，证明这些通常群居的鲨鱼可能存在独居阶段。沙虎鲨在一起的时间长达连续95小时、累计335小时，其中雄性之间的关系最为紧密。表现出裂变融合群体动态的物种给保护和管理带来了特别具有挑战性的问题，因为群体大小和组成的变化会影响种群估计，并放大人为影响。
