Hostname: page-component-cd9895bd7-fscjk Total loading time: 0 Render date: 2024-12-25T13:36:47.519Z Has data issue: false hasContentIssue false
  • English
  • Français

Influence of Food and Predatory Attack on Mysid Swarm Dynamics

Published online by Cambridge University Press:  11 May 2009

D.A. Ritz ,
J.E. Osborn  and
A.E.J. Ocken
D.A. Ritz
Affiliation:
Department of Zoology, University of Tasmania, Box 252C, GPO Hobart, Tasmania, Australia.
J.E. Osborn
Affiliation:
Department of Surveying and Spatial Information Systems, University of Tasmania, Box 252C, GPO Hobart, Tasmania, Australia
A.E.J. Ocken
Affiliation:
Department of Zoology, University of Tasmania, Box 252C, GPO Hobart, Tasmania, Australia.
Get access Rights & Permissions [Opens in a new window]

Extract

Using video and image analysis techniques we analysed the response of swarms of the mysid Paramesopodopsis rufa to food and predatory attack. After food was added to the tank, mysid aggregations initially (up to 45 s) increased in volume. Subsequently volume decreased significantly until it was smaller than the initial level. After a period of ~12 h during which no food was added, the swarm expanded to near its original volume. These changes are interpreted as resulting from a need by individuals to optimize food capture and protection. The pattern of volume changes in response to food was independent of aquarium size but the magnitude of the changes was reduced in a smaller tank.

Predatory attacks on mysid swarms were simulated using a model fish which ‘swam’ a single pass along the tank driven by an electric motor. Models (latex-covered real preserved fish), represented two different attack styles: ambush (seahorse Hippocampus abdominalis); and lunging (Australian salmon Arripis trutta). ‘Swimming’ speeds resembled those measured for real fish i.e. 0·5–2·0 cm s-1 for seahorse and 15 cm s-1 for salmon. Again changes in swarm volume were recorded. No obvious response by the swarm to the approaching seahorse was apparent; the aggregation simply parted to allow the fish through. No tailflips were seen among the mysids. The swarm resumed the original volume rapidly after the fish had passed. Approach of the salmon was evidently detected from further away, escape reactions were frequent and energetic, and tailflipping was common. After the fish had passed, it took longer for the original swarm volume to be restored. These results suggest that seahorse ambush techniques have evolved to minimize warning of the predator's approach. When the salmon ‘menaced’ the swarm at seahorse speeds, it appeared the mysids still reacted as though it was a ‘normal’ salmon attack so the fright response was not just a function of speed of attack.

Dynamic changes in swarm volume seem to be a useful simple index of motivational state of individuals.

Type
Research Article
Information
Journal of the Marine Biological Association of the United Kingdom , Volume 77 , Issue 1 , February 1997 , pp. 31 - 42
Copyright
Copyright © Marine Biological Association of the United Kingdom 1997

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Fenton, G.E., 1996. Diet and predators of Tenagomysis tasmaniae Fenton, Anisomysis mixta australis (Zimmer) and Paramesopodopsis rufa Fenton from south-eastern Tasmania (Crustacea: Mysidacea). Hydrobiologia, 323, 31–44.CrossRefGoogle Scholar
Jakobsen, P.J. & Johnsen, G.H., 1988. The influence of food limitation on swarming behaviour in the waterflea Bosmina longispina. Animal Behaviour, 36, 991–995.CrossRefGoogle Scholar
Larsson, P. & Dodson, S., 1993. Chemical communication in planktonic animals. Archiv für Hydrobiologie, 129, 129–155. [Review.]CrossRefGoogle Scholar
Metillo, E.B. & Ritz, D.A., 1993. Predatory feeding behaviour in Paramesopodopsis rufa Fenton (Mysidacea: Crustacea). Journal of Experimental Marine Biology and Ecology, 170, 127–141.CrossRefGoogle Scholar
Misund, O.A., 1993. Dynamics of moving masses: variability in packing density, shape, and size among herring, sprat, and saithe schools. Journal of Marine Science, 50, 145–160.Google Scholar
Murtaugh, P.A., 1984. Variable gut residence time: problems in inferring feeding rate from stomach fullness of a mysid crustacean. Canadian Journal of Fisheries and Aquatic Sciences, 41, 1287–1293.CrossRefGoogle Scholar
Nicol, S., 1986. Shape, size and density of daytime surface swarms of the euphausiid Meganyctiphanes norvegica in the bay of Fundy. Journal of Plankton Research, 8, 29–39.CrossRefGoogle Scholar
O'brien, D.P., 1987a. Description of escape responses of krill (Crustacea: Euphausiacea), with particular reference to swarming behaviour and the size and proximity of the predator. Journal of Crustacean Biology, 7, 449–457.CrossRefGoogle Scholar
O'brien, D.P., 1987b. Direct observations of the behaviour of Eitphausia superba and Euphausia crystallorophias (Crustacea: Euphausiacea) under pack ice during the Antarctic spring of 1985. Journal of Crustacean Biology, 7, 437–448.CrossRefGoogle Scholar
O'brien, D.P., 1988a. Direct observations of clustering (schooling and swarming) behaviour in mysids (Crustacea: Mysidacea). Marine Ecology Progress Series, 42, 235–246.CrossRefGoogle Scholar
O'brien, D.P., 1988b. Surface schooling behaviour of the coastal krill Nyctiphanes australis (Crustacea: Euphausiacea) off Tasmania, Australia. Marine Ecology Progress Series, 42, 219–233.CrossRefGoogle Scholar
O'brien, D.P., 1989. Analysis of the internal arrangement of individuals within crustacean aggregations (Euphausiacea: Mysidacea). Journal of Experimental Marine Biology and Ecology, 128, 1–30.CrossRefGoogle Scholar
O'brien, D.P. & Ritz, D.A., 1988. The escape responses of gregarious mysids (Crustacea: Mysidacea): towards a general classification of escape responses in aggregated crustaceans. Journal of Experimental Marine Biology and Ecology, 116, 257–272.CrossRefGoogle Scholar
O'brien, D.P., Tay, D. & Zwart, P.R., 1986. Laboratory method of analysis of swarming behaviour in macroplankton: combination of a modified flume tank and stereophotographic techniques. Marine Biology, 90, 517–527.CrossRefGoogle Scholar
Partridge, B.L., Pitcher, T.J., Cullen, J.M. & Wilson, J., 1980. The three-dimensional structure of fish schools. Behavioural Ecology and Sociobiology, 6, 277–288.CrossRefGoogle Scholar
Pitcher, T.J. & Parrish, J.K., 1993. Functions of shoaling behaviour in teleosts. In Behaviour of teleost fishes (ed. T.J., Pitcher), pp. 363–439. London: Chapman & Hall.CrossRefGoogle Scholar
Ritz, D.A., 1994. Social aggregation in pelagic invertebrates. Advances in Marine Biology, 30, 155–216.CrossRefGoogle Scholar
Ritz, D.A., 1996. Costs and benefits as a function of group size: experiments on a swarming mysid, Paramesopodopsis rufa. Mechanisms and functions. In Animal groups in three dimensions (ed. J.K., Parrish et al.). Cambridge University Press (in press).Google Scholar
Robinson, C.J. & Pitcher, T.J., 1989a. The influence of hunger and ration level on shoal density, polarization and swimming speed of herring, Clupea harengus. Journal of Fish Biology, 34, 631–633.CrossRefGoogle Scholar
Robinson, C.J. & Pitcher, T.J., 1989b. Hunger motivation as a promoter of different behaviours within a shoal of herring: selection for homogeneity in fish shoal? Journal of Fish Biology, 35, 459–460.CrossRefGoogle Scholar
Romey, W.L., 1995. Position preferences within groups: do whirligigs select positions which balance feeding opportunities with predator avoidance. Behavioural Ecology and Sociobiology, 37, 195–200.CrossRefGoogle Scholar