Biodiversity of Fishes Size Matters ( ) Rainer Froese

2 Extreme Size in Fishes What are the largest fishes on Earth? –FishBase, Tools, World Records 10 largest fishes What are the smallest fishes on Earth? –FishBase, Tools, World Records 10 smallest fishes

3 Why Does Size Matter? Some Things Increase! Predators are larger than their prey FB, FishBase Book, Trophic Ecology, The Predators Table Swimming speed increases with body length FB, FishBase Book, Morphology and Physiology, The Swimming and Speed Tables Fecundity increases with size (Fec = aL b ) median b = 3 FB, Coryphaena hippurus, More information, Fecundity, USA - Florida current, a = 0.252, b = 3.12 calculate Fec for 100 and 200 cm Publications increase with size

4 Why Does Size Matter? Some Things Decrease! Metabolism decreases with size FB, Oreochromis niloticus, More information, Metabolism, Relative oxygen consumption graph Growth decreases with size FB, O. niloticus, More information, Growth, Auximetric graph Natural mortality decreases with size FB, O. niloticus, More information, Growth, M vs. Linf graph Relative brain size decreases with size FB, O. niloticus, More information, Brains, Relative brain weight graph

5 Sometimes Size Doesn’t Matter Size at maturity FB, Oreochromis niloticus, More information, Growth, Reproductive load graph Body proportions FB, O. niloticus, More information, L-L relationship, e.g. SL = a + b TL if a = 0 then SL is a fixed ratio of TL

6 Size Distribution Frequency distribution of maximum lengths in 23,685 species of fishes, Median = 15.9 cm

7 Exercises Discuss with regards to size, phylogeny, habitat and trophic level (FB, Tools, World records): Group 1: 10 largest fishes Group 2: 10 smallest fishes Group 3: 10 fastest fishes (discuss fins) Group 4: 10 oldest fishes