Contemporary Growth Curves for Individual Humpback Whales in Eastern Australia Using Aerial Photogrammetry

Authors:
Open Access
Publisher website
Google Scholar
Abstract
Growth curves provide critical biological context for understanding life history, population dynamics, and responses to environmental change, yet our understanding of age–length relationships for humpback whales ( Megaptera novaeangliae ) remains largely based on measurements collected during commercial whaling operations from the mid‐20th century. These measurements may not reflect the growth trajectories of present‐day populations that have undergone substantial recovery and ecological change. Here, we establish contemporary, population‐specific, growth curves for eastern Australian humpback whales (breeding stock E1) using noninvasive aerial photogrammetry coupled with photo‐identification sighting histories. Total length measurements were collected from 865 individually identified whales between 2021 and 2024 and for a subset of these individuals, minimum age estimates were derived from long‐term photo‐identification sighting histories. Bayesian growth models were fitted to evaluate age–length relationships across multiple growth functions and age formulations. Growth was rapid during early life and approached an asymptotic adult length consistent with historical estimates for humpback whales in Australia. Predicted length at age 5 (median 10.93 m) and the age at which whales reached 90% of asymptotic length (median 6.58 years) indicated faster juvenile growth and earlier attainment of near‐adult size than reported elsewhere for contemporary Northern Hemisphere populations. The growth parameters and length‐at‐age estimates provide a baseline for demographic inference. Further, they support long‐term monitoring of growth and energetic constraints in a humpback whale population that has undergone one of the most rapid recoveries documented in a large whale species and is experiencing ongoing environmental change.
Funding Information
  • Pacific Whale Foundation

This publication has 23 references indexed in Scilit: