Life-history evolution in harvested populations: the importance of species interactions Anna Gårdmark 1*, Ulf Dieckmann 2 and Per Lundberg 1 1. Dept. Theoretical Ecology, Lund University 2. Adaptive Dynamics Network, IIASA, Austria *. Currently at: Population Biology, Dept. Evolutionary Biology, Uppsala University 1 (11)

2 (11) = large potential selection force  reproduce earlier  grow slower (become smaller)  change migration or swimming behaviour magnitude of commercial harvesting several traits have major impact on yields Why bother about evolution? selective mortality theory: fishing cause earlier maturation and smaller body size observations: genetic changes in age- and size-at-maturity in NorthSea plaice and NorthEast Arctic cod

2 (11) Why bother about evolution? Mean age-at-maturation (Data from Heino et al. 2002) observations: genetic changes in age- and size-at-maturity in NorthSea plaice and NorthEast Arctic cod

2 (11) = large potential selection force  reproduce earlier  grow slower (become smaller)  change migration or swimming behaviour magnitude of commercial harvesting several traits have major impact on yields Why bother about evolution? selective mortality only studied in single species! theory: fishing cause earlier maturation and smaller body size observations: genetic changes in age- and size-at-maturity in NorthSea plaice and NorthEast Arctic cod Mean age-at-maturation

predator resident prey mutant prey 3 (11) fishing = dynamic selection pressure e.g. prey-regulated predation Density-dependent species interactions

Model: evolution of age-at-maturation 4 (11) fishing predation Evolving trait age-at-maturation 1y2y ³3y reproduction survival

Model: evolution of age-at-maturation 4 (11) fishing Evolving trait age-at-maturation 1y2y ³3y reproduction survival

Model: evolution of age-at-maturation 4 (11) fishing predation Evolving trait age-at-maturation 1y2y ³3y reproduction survival

Model: evolution of age-at-maturation 4 (11) fishing predation Evolving trait age-at-maturation 1y2y ³3y reproduction survival

Model: evolution of age-at-maturation 4 (11) fishing predation Evolving trait age-at-maturation 1y2y ³3y reproduction survival

Model: evolution of age-at-maturation 4 (11) fishing predation Evolving trait age-at-maturation 1y2y ³3y reproduction survival

5 (11) Effects of fishing and predation (1) Fishing of 2- and 3-y-olds causes earlier maturation 123 Constant predation on 2- and 3-y-olds causes earlier maturation 123 Fishing and prey-dependent predation on age 1 predation has no effect, fishing of 2- and 3-y-olds causes earlier maturation 123

6 (11) Effects of fishing and predation (2) Fishing and prey-dependent predation on age 2 predation causes earlier maturation, fishing of 1-y-olds causes later maturation, fishing of 2- and 3-y-olds has no effect 123

Fishing and prey-dependent predation on age 2 7 (11) a * = age-at-maturation Fishing causes either: (1) later maturation or (2) has no effect on age-at-maturation 123 Predation on age 2 (attack rate) Harvest proportion 01 h2h2 h3h a*= 3a*= 3 a*= 2a*= 2 a*=2a*=2 a*= 3a*= h1h1 a*= 3a*= 3 a*= 2a*= 2 = both species extinct = predator extinct = species coexist 1

8 (11) Effects of fishing and predation (2) Fishing and prey-dependent predation on age 3 evolutionary effect depends on the strength of predation and fishing 123 Fishing and prey-dependent predation on age 2 predation causes earlier maturation, fishing of 1-y-olds causes later maturation, fishing of 2- and 3-y-olds has no effect 123

Fishing and prey-dependent predation on age (11) a * = age-at-maturation Fishing causes either: (1) later maturation, (2) earlier maturation or (3) bistability Predation on age 3 (attack rate) Harvest proportion 1 01 h2h2 h3h a*= 3a*= 3 a*=2a*=2 a * = 2 or 3 a*=2a*=2 a*= 3a*= h1h1 a*= 3a*= 3 a*=2a*=2 = both species extinct = predator extinct = species coexist

10 (11) Conclusions Evolutionary response to harvesting depends on species interactions harvesting of a prey that is predated can have ambiguous evolutionary effects on age-at-maturation (1. earlier maturation, 2. later maturation, 3. change depend on age-at-maturation in unharvested population) if… predator is dependent on the prey (e.g. for growth) predator selectively feeds on intermediate aged or oldest prey predation has significant impact on prey dynamics

Thank you! Ulf Dieckmann, ADN, IIASA, Austria Mikko Heino, Institute for Marine Research, Bergen, Norway Jörgen Ripa, Lund University, Sweden FORMAS, Sweden Kungliga Fysiografiska Sällskapet, Sweden Contact: 11 (11)