Biodiversity of Fishes Understanding Longevity Rainer Froese GEOMAR, Kiel, Germany 8.12.2016

Longevity in Fish Maximum age (tmax) on record for a species Maximum time available for growth and reproduction Used as proxy for natural mortality M ~ 4.5/tmax 1 of 5 criteria to estimate resilience

Taylor (1958) Longevity as age at 95% of L∞ Longevity (years) = 3 / K where t is age, L∞ is the asymptotic body length, K indicates how fast L∞ is approached, and t0 is the hypothetical age at zero length. Taylor, C.C., 1958, Cod growth and temperature., J. Cons. Int. Explor. Mer. 23:366-370.

Longevity vs Taylor’s 3/K 1 : 1 353 species, FishBase 11/2006

Longevity vs Temperature

Longevity vs Maximum Length Maximum age and length known for 1036 species of fishes, FishBase 11/2006

Maximum Length vs Longevity Maximum length and age known for 1036 species of fishes, FishBase 11/2006 (Slope = 0.80, 95% CL = 0.76-0.84, r2 = 0.6124)

L∞ vs tmax within Species 6410 growth studies FishBase 11/2006 Median slope for populations within 141 species = 0.42 (95% CL = 0.39-0.46)

Longevity vs Age at Maturity 1 : 1 tmax ~ 4 * tm Froese and Binohlan 2000

Empirical Equations for Longevity Froese and Binohlan 2000

Longevity vs Environment Diadromous

Longevity vs Habitat

Longevity vs Trophic Level

Facts Relative size at maturity (Lm / Lmax) Fish 0.44 (n=530, 95% LCL =0.421, UCL=0.451) Marine mammals 0.76 (n=9, LCL=0.716, UCL=0.803) Birds 1.0 Relative age at maturity (tm / tmax) Fish 0.24 (n=229, LCL=0.224, UCL=0.253) Marine mammals 0.13 (LCL= 0.0913, UCL = 0.198) Birds 0.05 (LCL=0.0364, UCL=0.0695)

Whale shark vs Fin whale The largest fish, the Whale shark (Rhincodon typus) needs about 9 years to reach maturity at about 5.5 m and 750 kg, and about 60 years to reach a maximum length of 14 m and 12 tons. The fin whale (Balaenoptera physalus) needs about 7 years to reach maturity at a size of about 20 m and about 36 tons, with a maximum size of about 25 m and 70 tons.

Whale shark vs Fin whale

White shark vs Killer whale Great white shark females take about 12 years to reach maturity at 4.5-5 m and about 0.8 tons; they need 36 years to reach a maximum size of 7.2 m and 3.4 tons; Killer whales (Orcinus orca) reach maturity in 6-10 years at 5-6 m length and about 1.8 tons, with the typical size of about 7 m and 3.8 tons reached a few years later.

Great white shark vs Killer whale

Conclusion Because of physics (e.g. gravity), organisms have a ‘bauplan’ or body architecture optimized for a certain average adult size; they maximize their fitness if they reach that size as fast as possible Fish growth is limited by the oxygen-temperature window, and thus they need all their life to reach maximum size Birds and mammals do not have this limitation (air breathers with constant body temperature) and reach maximum size early in life Gills suck, but they last: bowhead whales reach 130 years, cockatoos 60 years, humans 121 years, turtoise 180 years, fish (kois) > 200 years and Greenland shark 600??

Exercises Select one of these species: Orange roughy (Hoplostethus atlanticus) Beluga (Huso huso) Anchoveta (Engraulis ringens) Transparent goby (Aphia minuta) Discuss age (tmax, tm), habitat, food, growth, reproduction, suitability to fishing Use the graphs in FishBase to make your point