Growth, Natural Mortality, Length–weight Relationship, Maximum Length and Length-at-first-maturity of the Coelacanth Latimeria chalumnae

Abstract

Based on the re-interpretation of published data, the von Bertalanffy growth function parameters of the coelacanth, Latimeria chalumnae, are estimated as L_∞=218 cm total length, s.e. 23; K=0.059 (year⁻¹), s.e. 0.012; t₀=−3.3 (year), s.e. 0.5, corresponding to a life span of 48 years. The length–weight relationship of the form W=a*TL^∧b, with wet weight (W) in g and total length (TL) in cm, is estimated as a=0.0278, b=2.89, r²=0.893, n=87, range=42.5–183 cm TL. Using extreme value theory, the maximum length for female coelacanths is estimated as 199 cm TL (95% confidence interval=175–223 cm TL) and for males as 168 cm TL (95% confidence interval 155–180 cm TL). Based on data from seven females with embryos or mature eggs, the length-at-first-maturity for females is estimated to be about 150 cm TL, corresponding to an age of about 16 years. Based on the value of t₀=−3.3 years and on the presence of three scale rings found in a newborn coelacanth, the period of embryogenesis lasts for about three years, the longest known in vertebrates. The natural mortality rate is estimated at M=0.12. Population food consumption is found to be 1.4 times the existing biomass per year, and gross food conversion efficiency indicates that only 10% of the consumed food is utilized for somatic growth.