Biodiversity of Fishes Understanding Longevity Rainer Froese GEOMAR

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 t 0 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, Fish. Base 11/2006

Longevity vs Temperature

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

Maximum Length vs Longevity Maximum length and age known for 1036 species of fishes, Fish. Base 11/2006 (Slope = 0. 80, 95% CL = 0. 76 -0. 84, r 2 = 0. 6124)

L∞ vs tmax within Species 6410 growth studies Fish. Base 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 Fish. Base to make your point