Age and growth of the whale shark (Rhincodon typus) in the north-western Pacific

Abstract

This study estimated age and growth of the largest extant fish, the whale shark (Rhincodon typus) by counting vertebral band pairs from 92 specimens comprising 43 males (2.68–9.88 m total length [TL]), 30 females (1.60–7.02 m TL), and 19 unsexed individuals (2.83–6.67 m TL) taken by Taiwanese commercial fisheries during 2001–06. Growth band pairs up to 25 and 42 were counted for a 6.38-m TL female and a 9.88-m TL male, respectively. Using marginal increment ratio and centrum edge analysis, band pairs were postulated to be formed twice a year. The two-parameter von Bertalanffy growth function provided the best fit without significant differences between sexes. Growth parameters were calculated for both sexes as L∞ = 16.80 m TL, k = 0.037 year–1; annual band pair formation would modify these parameters to L∞ = 15.34 m TL, k = 0.021 year–1. Using data reported in another study for 50% size at maturity for males (8.1 m TL), and the largest immature and smallest mature females (8.7 and 9.6 m TL, respectively) in the Indo-Pacific, these TLs converted to ages at maturity of 17 years for males and 19–22 years for females. The longevity was calculated to be 80.4 years.

Enhancing insights into foraging specialization in the world's largest fish using a multi‐tissue, multi‐isotope approach

“…While these growth rates are of similar magnitude to estimates for wild R. typus , typically in the 20 to 40 cm/yr range (Hsu et al. , Norman and Morgan ), higher rates could be expected due to better nutrition in the aquarium. Indeed, growth as high as 75 cm/yr was observed for the maturing #3 in the present study, while another captive R. typus in Taiwan (67 cm/yr) also grew markedly faster than wild averages (Leu et al.…”

“…Annual growth approaching such high rates are only predicted to occur in the wild in young R. typus (e.g., 60 cm/yr at age 1 yr and BL ~ 120 cm), with rates likely declining below 30 cm/yr by age 19 (BL ~ 890 cm; Hsu et al. ). While the growth of the aquarium individuals may not be directly comparable to the observations of Hsu et al.…”

Whale Shark (Rhincodon typus) Seasonal Occurrence, Abundance and Demographic Structure in the Mid-Equatorial Atlantic Ocean

“…Female sharks commonly reach maturity at larger sizes than males. Whale shark females smaller than 9.0 m dissected in India [89,90] and South Africa [91] were all immature, while the smallest mature female observed in Taiwan was 9.6 m [92]. Geographic differences in size at maturity have been observed in other shark species [93–95] and may also occur for whale sharks given the information above.…”

The return of “Stumpy” the whale shark: two decades and counting

“…According to length‐at‐age estimates for whale sharks taken in Taiwanese commercial fisheries (Hsu et al . ), Stumpy and Zorro would have been between 14 and 15 years old when first recorded and would be projected to grow ~0.30–0.40 m per year. If correct, this suggests that Stumpy and Zorro are now in their late 30s, yet their growth has been negligible over the past two decades.…”

“…Citizen science has demonstrated that whale sharks exhibit a high degree of site fidelity, and with longevity conservatively estimated to be at least 80 years (Hsu et al . ), there is the opportunity for this iconic species to be the focus of long‐term natural history studies. The analysis of photographic databases is becoming increasingly popular with citizen scientists, who have gathered information on climate change, invasive species, ecological restoration, and population ecology (Silvertown ).…”