caa a22 4500 469096608 CHVBK 20180323133032.0 cr unu---uuuuu 170328e19920101xx s 000 0 eng 10.1007/BF00319024 doi (NATIONALLICENCE)springer-10.1007/BF00319024 Possible indirect interactions between transient and resident killer whales: implications for the evolution of foraging specializations in the genus Orcinus [Elektronische Daten] [Robin Baird, Peter Abrams, Lawrence Dill] Summary: Two distinct forms of killer whale (Orcinus orca) occur off the coast of British Columbia, Alaska and Washington State. These have different diets, and may be reproductively isolated. Because the primary food of transient whales (pinnipeds) is a potential competitor for the primary food of resident whales (salmon), or for the smaller fishes on which salmon feed, there should be an indirect interaction between the two forms of killer whale. We use simple mathematical models to show that this interaction will be either of a "plus-minus” type, or a "plus-plus” type (indirect mutualism), depending on whether or not pinnipeds and residents are on the same trophic level. In the case of the "plus-minus” interaction, increasing the population density or improving the environmental conditions of transients will increase the population density of residents, while increasing resident populations will reduce the equilibrium population size of transients. In the case of the "plus-plus” interaction, increasing the population density or improving the environmental conditions of transients will increase the population density of residents, while increasing resident populations will reduce the equilibrium population size of transients. In the case of the "plus-plus” interaction, increasing the population density or improving the environmental conditions of transients will increase the population density of residents, and vice versa. Such effects may not be currently manifest due to reduced populations at most levels in the food web. Regardless, considering such indirect interactions may be important for the management of many of the species involved, and can also provide a valuable framework for examining the evolution of the two forms of killer whales. Frequency-dependent indirect interactions, acting in concert with density-dependence within populations and disruptive selection on prey-type specific foraging characteristics, may have favoured reproductive isolation of the two forms of killer whales. We suggest that these two forms of whale are in the process of speciating, i.e., the two forms are incipient species. Springer-Verlag, 1992 Foraging nationallicence Sympatric speciation nationallicence Killer whales nationallicence Indirect interactions nationallicence Baird Robin Behavioural Ecology Research Group, Department of Biological Sciences, Simon Fraser University, V5A 1S6, Burnaby, B.C., Canada aut Abrams Peter Department of Ecology, Evolution and Behavior, University of Minnesota, 318 Church St. S.E., 55455, Minneapolis, MN, USA aut Dill Lawrence Behavioural Ecology Research Group, Department of Biological Sciences, Simon Fraser University, V5A 1S6, Burnaby, B.C., Canada aut Oecologia Springer-Verlag 89/1(1992-01-01), 125-132 0029-8549 89:1<125 1992 89 442 https://doi.org/10.1007/BF00319024 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00319024 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Baird Robin Behavioural Ecology Research Group, Department of Biological Sciences, Simon Fraser University, V5A 1S6, Burnaby, B.C., Canada aut NATIONALLICENCE 700 1- Abrams Peter Department of Ecology, Evolution and Behavior, University of Minnesota, 318 Church St. S.E., 55455, Minneapolis, MN, USA aut NATIONALLICENCE 700 1- Dill Lawrence Behavioural Ecology Research Group, Department of Biological Sciences, Simon Fraser University, V5A 1S6, Burnaby, B.C., Canada aut NATIONALLICENCE 773 0- Oecologia Springer-Verlag 89/1(1992-01-01), 125-132 0029-8549 89:1<125 1992 89 442 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer