New Use of FishBase Data: Estimating the intrinsic rate (rmax) of population increase Rainer Froese GEOMAR 14th FishBase Symposium Amphitheatre Rouelle, MNHN 9 September 2016, Paris, France

Question If you were granted the wish to know one number for every species on Earth, what number would you pick?

Answer For every population, there is one number that summarizes maximum size, longevity, maturity, mortality, somatic growth, and reproductive success: rmax The maximum intrinsic rate of population increase

Thomas Robert Malthus (1766 – 1834, English Economist)  

World Population Growth "The power of population is indefinitely greater than the power in the earth to produce subsistence for man"

Pierre François Verhulst (1804 – 1849, Belgian Mathematician)   (1844)

Logistic Curve Properties BioDivPopGrowthMSY.xls

Importance to Conservation How fast populations can recover from a depleted state is determined by rmax Doubling time = log(2) / rmax ̴ 0.7 / rmax rmax = 0.7 → 1 year rmax = 0.07 → 10 years

Milner Baily Schaefer (1912 – 1970, US Fisheries Scientist)    

The Schaefer Model BioDivPopGrowthMSY.xls

Life History Correlates of rmax rmax = 2 Fmsy (Schaefer 1954) rmax ̴ 2 M because M ̴ Fmsy (Gulland 1971) rmax ̴ 3 k because k ̴ 2/3 M (Jensen 1996) rmax ̴ 9/tmax because tmax ̴ 3/k (Taylor 1958) rmax ̴ 3.3/tgen because tgen ̴ 1/k (Roff 1984) rmax = f(Fecundity < 1000) (Musick 1999) These relations were used to predict rmax in FishBase for currently close to 1000 species:

Resilience

rmax vs Size

Differences by Class

Climate

Freshwater vs Marine

Environment

Migratory Behavior

Phylogenetic Uniqueness

Next Steps Include published estimates of rmax in FishBase Use a Bayesian hierarchical approach to estimate rmax for all species [ Beware what you wish for…]

Thank You