Christian-Albrecht Universität zu Kiel Leibniz Institut für Meereswissenschaften Habilitationsschrift Life-History Strategies of Recent Fishes: a Meta-Analysis vorgelegt von Dr. Rainer Froese Kiel, November 2005 1 Table of Content Abstract ...................................................................................................................................... 4 Introduction ................................................................................................................................ 6 Material and Methods............................................................................................................... 11 Results and Discussion............................................................................................................. 13 Key Components of Life-history Strategies......................................................................... 13 Phylogeny......................................................................................................................... 13 Size................................................................................................................................... 14 Trophic Level ................................................................................................................... 16 Productivity ...................................................................................................................... 17 Relationships between Size, Trophic Level and Productivity.............................................. 22 Available Combinations of Traits: Life-History Strategies ................................................. 25 Life-history Strategies as a Function of Phylogeny ............................................................. 33 Building the Database for All Fishes ................................................................................... 45 Modelling Trophic Levels................................................................................................ 45 Modelling Productivity .................................................................................................... 47 Constraints in Life-history Space Revisited......................................................................... 56 Phylogeny and Strategies Revisited ..................................................................................... 60 A Chronology of Life-history Strategies.............................................................................. 66 Life-history Strategies and Environment ............................................................................. 70 Salinity ............................................................................................................................. 70 Climate Zones .................................................................................................................. 80 Life-history Strategies and Aquatic Ecosystems.................................................................. 91 Zoogeographic Realms..................................................................................................... 91 Oceans ............................................................................................................................ 101 Habitats........................................................................................................................... 109 Life-history Strategies and Functional Morphology .......................................................... 119 Body shape ..................................................................................................................... 119 Brain Size ....................................................................................................................... 129 Life-history Strategies and Behaviour................................................................................ 136 Reproductive guild ......................................................................................................... 136 Distributional range........................................................................................................ 144 Migratory behaviour....................................................................................................... 144 Life-history Strategies and Human Impact on Fishes ........................................................ 151 Resilience to Fishing Pressure........................................................................................ 151 Status of Threat .............................................................................................................. 153 How to Measure Success of Life-history Strategies .......................................................... 159 Abundance...................................................................................................................... 159 Area of Distribution ....................................................................................................... 167 Impact............................................................................................................................. 174 Some Meta-Analyses.............................................................................................................. 178 Critique of Data and Methods ............................................................................................ 178 General Properties of Life-History Strategies.................................................................... 179 Testing of Selection Theories............................................................................................. 180 Correlations of Life-history Strategies with Functional Morphology, Behaviour, and Resilience ........................................................................................................................... 184 Competition........................................................................................................................ 185 Number of Higher Taxa and Strategies as a Function of Species Richness ...................... 186 Relationship between Numbers of Species and Numbers of Strategies............................. 189 More Research Needed ...................................................................................................... 192 2 Summary ................................................................................................................................ 194 Size................................................................................................................................. 194 Productivity .................................................................................................................... 194 Trophic level .................................................................................................................. 194 Life-history Strategies.................................................................................................... 194 Influence of Phylogeny on Life-history Strategies ........................................................ 195 Selection Theories.......................................................................................................... 195 Correlations with Functional Morphology, Behaviour and Resilience.......................... 195 Success of Life-history Strategies.................................................................................. 195 Acknowledgments.................................................................................................................. 197 References .............................................................................................................................. 198 3 Abstract This study explores life-history strategies of recent fishes based on a data set that is two orders of magnitude larger than those used in previous studies. Trophic level, size and productivity were taken as key traits and proxies for many other closely related traits. Size was strongly correlated with most life-history traits of fishes and also with morphological characters, behaviour, and preferred environmental conditions. Size was also a good predictor of placement on the r-K continuum. Productivity was derived from growth, age at maturity, maximum age, and fecundity data. It was positively correlated with metabolism and level of activity and was also an indicator for placement of species on the r-K continuum. It was strongly correlated with most life-history traits of fishes and also with morphological characters, behaviour, and preferred environmental conditions. It was negatively correlated with status of threat. The position of species in the food web was shown to restrict life-history options. The addition of trophic level as an orthogonal axis on the r-K continuum revealed unoccupied regions such as the combination of small size and high productivity with either herbivory or top-predatory, and the combination of very large size and very low productivity with herbivory. Discrete classes of size, trophic level and productivity were used to define 80 life history strategies. Only 50 of these strategies were used by recent species, with an exponential decline in species’ numbers from the most to the least used strategies. This decline is interpreted as an exponential increase in constraints associated with less-used strategies. Analysis of trade-off or constraint curves in life-history space revealed unoccupied areas as well as local maxima, i.e., areas occupied