Bola umpan

Bola umpan terjadi saat sekawanan ikan kecil membentuk formasi bundar. Tindakan tersebut adalah sebuah tindakan pertahanan terakhir yang dilakukan oleh ikan berkelompok kecil saat mereka terancam oleh para predator. Ikan berkelompok kecil disantap oleh banyak jenis predator, dan untuk alasan itu, mereka disebut ikan umpan atau ikan mangsa.

• Burgess EA (2006) "Foraging ecology of common dolphins (Delphinus sp.) in the Hauraki Gulf, New Zealand" MSc thesis, Institute of Natural Resources, Massey University.
• Dement J Species Spotlight: Atlantic Sailfish (Istiophorus albicans) littoralsociety.org. Retrieved 28 March 2011.
• Leighton TG, PR White and Finfer DC (2009) "Hypotheses on the acoustics of whales, dolphins and porpoises in bubbly water" Proceedings of the Third International Conference on Underwater Acoustic Measurements, Technologies and Results.
• Fetecau R (2010) "Collective behavior of biological aggregations in two dimensions: a nonlocal kinetic model" Mathematical Models and Methods in Applied Sciences, August 2010.
• Marshall Cavendish Corporation (2004) Encyclopedia Of The Aquatic World Page 164, Marshall Cavendish. ISBN 978-0-7614-7418-0.
• Mate BR (2010). "Sperm whales instrumented with ARGOS-GPS-TDR tags demonstrate coordinated dive behavior suggesting cooperative 'bait-ball' feeding on Humbolt [sic] squids". Proceedings from the 2010 AGU Ocean Sciences Meeting. Diarsipkan dari versi asli tanggal 2012-04-04. 
• Robinson KP, Stevick PT and MacLeod CD (2007) An integrated approach to non-lethal research on minke whales in European waters Diarsipkan 2011-10-02 di Wayback Machine. European Cetacean Society, Special publication series, No 47.
• Robinson KP and Tetley MJ (2007) "Behavioural observations of foraging minke whales (Balaenoptera acutorostrata) in the outer Moray Firth, north-east Scotland" J. Mar. Biol. Assoc. U. K., 87: 85–86. DOI:10.1017/S0025315407054161
• Sfakiotakisa M and Tsakiris DP (2007) "Neuromuscular control of reactive behaviors for undulatory robots" Neurocomputing, 70(10–12): 1907–1913.
• Steiner L (1995) "Rough-toothed dolphin, Steno bredanensis: a new species record for the Azores, with some notes on behaviour" Life and Marine Sciences, 13A: 125–127.
• Waters, Hannah (2010) Now in 3-D: The shape of krill and fish schools Scientific American. Invited commentary, 10 November 2010.

• Queuing up for dinner: Dolphins enjoy sardine feeding frenzy Daily Mail, 15 July 2009. – this article has some spectacular images
• Computer simulations of bait balls
• How Humpback Whales Catch Prey With Bubble Nets ScienceDaily. 24 June 2011.