Challenge of monitoring cohesive movement in homing fish using fine-scale 3D positioning

Organisms live in groups on diverse spatial and temporal scales. Living in groups provides various advantages (Krause & Ruxton 2002, Sumpter 2010), such as increasing food search efficiency (Pitcher et al. 1982), reducing predation risk (Partridge 1982, Magurran 1990), and saving locomotion energy (Portugal et al. 2014, Hemelrijk et al. 2015, Marras et al. 2015). Navigational ability enhancement is also an advantage of group movement. For example, pigeons home more efficiently when travelling in flocks than when flying alone (Biro et al. 2006, Dell’Ariccia et al. 2008), and king penguin chicks return to their places of origin more efficiently when travelling in pairs than when moving alone (Nesterova et al. 2014).