Oral Presentation Australian Society of Fish Biology and Oceania Chondrichthyan Society Conference 2016

Age, growth and maturity of oceanic whitetip shark (Carcharhinus longimanus) from Papua New Guinea (#49)

Brooke M D'Alberto 1 , Andrew Chin 1 , Jonathan J Smart 1 , Leontine Baje 1 2 , William T White 3 4 , Colin A Simpfendorfer 1
  1. Centre for Sustainable Tropical Fisheries and Aquaculture & College of Science and Engineering, James Cook University, Townsville, QLD, Australia
  2. National Fisheries Authority, Port Moresby, Papua New Guinea
  3. CSIRO Oceans & Atmosphere, Hobart, TAS, Australia
  4. Australian National Fish Collection, CSIRO National Research Collections Australia, Hobart, TAS, Australia

Oceanic whitetip sharks (Carcharhinus longimanus) in the Western Central Pacific Ocean have been overfished and require improved assessment and management to enable planning recovery actions. Samples from 103 individuals, 70 males (76.0 – 240 cm TL) and 33 females (128 – 235 cm TL) were used to estimate age, growth and maturity parameters from sharks retained by longline fisheries in Papua New Guinea (PNG). Back calculation was used to account for the low number of juveniles and a multi-model framework with AICC used to estimate growth parameters. The von Bertalanffy growth model (VBGF) provided the best fitting growth model for both sexes. Parameter estimates for males were L∞ = 314 cm TL, k = 0.059 yr-1, L0 = 75.1 cm TL, and L∞ = 317 cm TL, k = 0.057 yr-1, L0 = 74.7 cm TL for females. Maximum age was estimated to be 18 years for males and 17 years for females, with a calculated longevity of 24.6 years and 24.9 years, respectively. Males matured at 10.8 years and 193 cm TL, while females matured at 15.8 years and 224 cm TL. These are the first estimates of life history parameters for C. longimanus from PNG. Carcharhinus longimanus is a slow growing, late maturity species, with regional variation in life history parameters highlighting increased vulnerability to fishing pressure in this region.