The Research in FishBase Rainer Froese IfM-GEOMAR
Classes of Fishes
There are Six Classes of Fishes ClassesCommon ancestor (million y) Orders (n) Families (n) Genera (n) Species (n, %) Myxini (hagfishes) Cephalaspidomorphi (lampreys) Holocephali (chimaeras) Elasmobranchii (sharks and rays) Sarcopterygii (lobe-finned fishes) Actinopterygii (ray-finned fishes) ,64028, Total ,84029, Source: FishBase 09/2006
Key Trait: Size smallmediumlargevery large 23,603 species
What You Eat You Are (+1) Trophic level Phytoplankton Top predators Prey fish Zooplankton * *.*. *.* 10% *
Key Trait: Trophic Level 7,161 species herbi- vore omnivorelow-level predatormid-level predator top- predator
Key Trait: Productivity (modified after Musick 1999) ParameterHighMediumLowVery low r max (1/year)> – – 0.15< 0.05 t d (years)< > 14 Interest rate (%)> 6517 – < 5 K (1/year)> – – 0.15< 0.05 Fecundity (1/year)> 10, – – 100< 10 t m (years)< 12 – 45 – 10> 10 t max (years)1 – 34 – 1011 – 30> 30
Productivity is a Proxy for Metabolism
Trait Correlation: Size vs Troph
Predators are Larger than Prey
Trait Correlation: Size vs Productivity
Phylogeny Limits Traits: Size Hagfish Lampreys Chimaeras Sharks & rays Lobe-finned Ray-finned small medium large very large
Phylogeny Limits Traits: Troph Hagfish Lampreys Chimaeras Sharks & rays Lobe-finned Ray-finned
Occupation of Size-Troph Space
Occupation of Size-Productivity Space
Occupation of Troph-Productivity Space
Occupation of size–productivity– troph-space for 20,480 species of fishes. Full cell width is 1000 species. Source: FishBase 11/2004
Occupation of size–productivity– troph-space for 620 species of sharks and rays. Full cell width is 1000 species. Source: FishBase 11/2004
Life Span and Growth Taylor 1958 Age at 0.95 L ∞ t max = 3/K
Life Span and Size
The Most Important Point in Life where growth rate is maximum where gonad growth rate is maximum where likely reproductive effort is maximum (l t m t function) where reproductive biomass of the cohort is maximum t opt = 1.65 E
The Most Important Point in Life t opt = 1.65 E L opt = 0.67 L ∞ W opt = 0.3 W ∞
Evolution Does Not Miss… 0.67 L ∞ = t opt 0.35 L ∞ = t opt - E live bearers sharks & rays low fecundity high fecundity survival of offspring Related to parent size survival of offspring indepenent of parent size
But Fishing Does… Start before first maturity Double mortality (if not more) E = 1/M Reduce reproductive phase by half Undermine the productivity on which it depends
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