This is a
prestigious lectureship instituted in memory of Cam Stevenson, the long-time
Editor of the Canadian Journal of Fisheries and Aquatic Sciences (CJFAS), published by NRC
Press and is conferred upon a young, energetic and creative researcher
at the cutting edge of an aquatic discipline. Each year a Lecturer is selected
by the Journal's Editorial Board. In the Spring of
each year a call for nominations is sent to the Chairs of Zoology and Biology
departments across
Ecological
speciation: Canadian fishes and the illusion of ubiquity.
Ecological speciation occurs when adaptation to
different environments drives the evolution of reproductive isolation. This
process is thought to have been very important in the evolution of biological
diversity, and Canadian fishes have figured prominently in the theory’s
development and widespread acceptance. Indeed, ecological speciation seems so
rampant in Canadian fishes (sticklebacks, coregonids,
salmonids, osmerids, and centrarchids) that one can get the impression of ubiquity.
Eager to ride on the coat-tails of this exciting work, I have used similar
methods to investigate ecological speciation in lake/stream stickleback and in
Trinidadian guppies. Much to my initial dismay, I have failed to find simple
and strong signatures of ecological speciation. Setting aside the possibility
of personal incompetence, my failure to duplicate previous results may simply
reflect a positive bias in the reporting of ecological speciation. In
retrospect, such a bias seems obvious given that essentially all published studies
of ecological speciation are confirmatory, whereas many populations in
different environments likely show little, if any, hint of incipient
speciation. I argue for the merits of further work on populations that show
little evidence of ecological speciation, thus enabling analyses along a
continuum from zero to complete reproductive isolation. This comparative
approach may help inform the conditions that promote and constrain ecological
speciation. Of particular importance may be the nature of mating systems, the
amount of dispersal, the role of competition, and the genetic basis for
adaptation and reproductive isolation.