Evolution is the underlying process shaping the world’s
biota. Humans have significantly altered the environment and our activities
have exerted tremendous selective forces on living resources. Harvest is one
of these activities and has the potential to cause rapid evolutionary change
in a variety of important traits and behaviours. Unfortunately, fisheries science
has been slow to acknowledge the occurrence or importance of harvest-induced
evolution; one reason is that genetic changes are believed by many to occur
over extremely long timescales. It is becoming increasingly evident, however,
that evolution can unfold in only a few generations, a timescale that is relevant
ecologically and that should make evolutionary change a concern to managers
of exploited populations.
My research examines the interacting ecological and evolutionary impacts of
humans on fish populations and aquatic communities. I use a combined empirical
and theoretical approach to study those processes which scale from genes to
populations and the aim of my research is to bring an evolutionary perspective
to fisheries science in particular, and to resource management in general.
In collaboration with Dr.
Mikko Heino and Dr.
Ulf Dieckmann, I have been developing the eco-genetic modeling approach.
The goal of this modeling approach is to follow the evolution of quantitative
life-history traits in an ecologically rich setting. In an eco-genetic model,
the ecological and evolutionary timescales are fully intertwined so that the
rate, transients, magnitude, and endpoints of evolution can be examined. The
genetic component of eco-genetic models includes the quantitative inheritance,
heritable variation, and phenotypic expression of life-history traits. The ecological
setting of an eco-genetic model includes density and frequency-dependence, phenotypic
plasticity, and the explicit modeling of processes including individual growth,
maturation, reproduction, inheritance, and mortality. An example eco-genetic
model can be found in Dunlop et al. (2007).
Eco-genetic models are particularly suited to studying fisheries-induced evolution
because they are tightly coupled with the type of empirical data available for
many fish populations, they can be used to follow the evolution of multiple
life-history traits (e.g., genetic determinants of growth, maturation tendency,
reproductive effort), and they can be used to predict the effects of alternative
management measures on the traits, recruitment processes, and population dynamics
of exploited stocks.
Anne Maria Eikeset is developing an eco-genetic model of Northeast Arctic cod, the
world’s largest cod stock. An extension of Ms. Eikeset’s work is
to combine the eco-genetic model with an economic model to explore the economic
impacts of fisheries-induced evolution in Northeast Arctic cod. Dr. Katja Enberg
is using eco-genetic models to explore the ecology and evolution of recovery
in exploited fish populations. Davnah Urbach is working on the evolution of
mating preference and the impact of fishing on sexual selection. Research on
the influence of stock structure on fisheries-induced evolution in Icelandic
cod is being carried out by Heidi Pardoe. With the help of an eco-genetic model,
Dr. Véronique Thériault is researching the influence of fishing
on the evolution of residency in brook charr. Also in development is an eco-genetic
model used to study the influence of marine reserves on the evolutionary effects
of fishing in species which undergo an annual spawning migration.
(2) The assessment and management
of evolving resources
Although there are a growing number of studies examining fisheries-induced
evolution, it is not clear what management actions should be taken to mitigate
these evolutionary effects. In many cases, the most effective management actions
will depend on a variety of factors including the nature of the fishery, the
history of exploitation of the stock, and the life-history characteristics of
a stock.
Both recreational and commercial fishing exert tremendous
selective pressures on fish populations. This photo shows recreational fishing
for Chinook salmon in Owen Sound, Ontario, Canada.
(3) The interplay among evolution, ecology, and
space
Spatial
processes interact with eco-evolutionary dynamics to influence many factors
such as the population dynamics, bioenergetics, species interactions, economy,
and management of living resources. However, while the study of eco-evolutionary
dynamics is beginning to grow, research on the interplay of these dynamics with
spatial processes is still in its infancy.
Space is of obvious importance to species that undergo migrations. Preliminary
research indicates that harvest influences the evolution of residency in salmonids
(Thériault et al. 2008)
and the evolution of migration distance in Northeast Arctic cod (Jørgensen
et al. In press). The efficacy of marine protected areas will
also depend on the interplay between evolution and space and on the bio-economic
impacts of fisheries-induced evolution.
(4) Smallmouth bass life history
My PhD thesis used the smallmouth bass as a study species for examining the
processes governing life history variation in freshwater fish. I continue to
be interested in this fascinating species. The smallmouth bass shows paternal
nest-guarding: after spawning the male remains for up to 6 weeks to guard the
young brood as it develops. The presence of parental care favours large body
size in male parents, a selective force which can alter the evolutionary response
to harvest (Dunlop et al. 2007).
The range of smallmouth bass has been expanding northwards (Dunlop
and Shuter 2006), disrupting native species assemblages (Jackson
2002). As the species invades new lakes and streams, differences in local
environments drive divergence through phenotypic plasticity and genetic adaptation
(Dunlop et al. 2005a,b; 2007). The
smallmouth bass is also an important recreational species and faces pressures
from the expansion of double-crested cormorants (Lantry
et al. 2002) and the invasion of round gobies (Steinhart
et al. 2008) in the Great Lakes.
Mark-recapture survey of nesting male smallmouth bass.
Biography
I completed a Bachelor of Science degree in 1999 at the University
of Guelph, Canada and completed my Ph.D. in 2005 at the University of Toronto,
Canada. My Ph.D. research examined the patterns and processes of life history
variation in harvested freshwater fish. During my Ph.D., I was supervised by
Dr. Brian
Shuter (Ontario Ministry of Natural Resources) and Dr.
Helen Rodd (University of Toronto). In the summer of 2005, I started postdoctoral
research at the International Institute for Applied Systems Analysis (IIASA)
in Austria, under the guidance of Dr.
Ulf Dieckmann in the Evolution and Ecology Program. My research at IIASA
was part of The European Research Training Network on Fisheries-induced
Adaptive Changes in Exploited Stocks. In fall 2006, I moved to Bergen, Norway
to conduct postdoctoral research with Dr.
Mikko Heino at the Institute
of Marine Research and University of Bergen. My current research focuses
on fisheries-induced evolution and is funded by the Norwegian research council
project, “Sustainable
harvesting of marine resources: interactions between demographic, ecological
and evolutionary effects of fishing”.
I owe much of my foundation in fisheries science and aquatic
ecology to the 10 summers I spent working as a student at the Harkness
Laboratory of Fisheries Research in Alqonquin Provincial Park, Ontario,
Canada.
Dunlop, E.S., Orendorff, J.A., Shuter, B.J., Rodd,
F.H., and Ridgway, M.S. 2005a. Diet and divergence of introduced smallmouth
bass, Micropterus dolomieu, populations. Canadian Journal of Fisheries
and Aquatic Sciences 62:1720-1732.
Dunlop, E.S., Shuter, B.J., and Ridgway, M.S. 2005b.
Isolating the influence of growth rate on maturation patterns in the smallmouth
bass, Micropterus dolomieu. Canadian Journal of Fisheries and Aquatic
Sciences 62:844-853.
Dunlop, E.S., Shuter, B.J.. 2006. Native and introduced
populations of smallmouth bass differ in the concordance between climate and
somatic growth. Transactions of the American Fisheries Society 135:1175-1190.
Dunlop, E.S., Shuter, B.J., and Dieckmann, U. 2007.
The demographic and evolutionary consequences of selective mortality: Predictions
from an eco-genetic model for smallmouth bass. Transactions of the American
Fisheries Society 136:749-765.
Jackson, D.A. 2002. Ecological effects of Micropterus
introductions: The dark side of black bass. Black Bass: Ecology, Conservation,
and Management. D.P. Philipp and M.S. Ridgway eds. Bethesda, Maryland, American
Fisheries Society.
Jørgensen, C., Dunlop, E.S., Opdal,
A.F., Fiksen, Ø. The evolution of spawning migrations: The role of individual
state, population structure, and fishing-induced changes. In press Ecology .
Lantry, B.F., and Eckert, T.H., Schneider, C.P., and Chrisman,
J.R. 2002. The relationship between the abundance of smallmouth bass and double-crested
cormorants in the eastern basin of Lake Ontario. Journal of Great Lakes Research
28: 193-201.
Steinhart, G.B., Dunlop, E.S., Ridgway, M.S., Marschall,
E.A. 2008. Should I stay or should I go: Optimal parental care decisions of a nest-guarding
fish. Evolutionary Ecology Research 10:351-371
Thériault, V., Dunlop, E.S., Dieckmann, U.,
Bernatchez, L., Dodson, J.J. 2008. The impact of fishing-induced mortality on the
evolution of alternative life-history tactics in brook charr. Evolutionary Applications 1:409-423.