Humpback whale in the ocean viewed from above, marked with digital photogrammetry lines to measure its body dimensions.
Photo Credit: Courtesy of Griffith University
Scientific Frontline: Extended "At a Glance" Summary: Humpback Whale Growth Rates
The Core Concept: Eastern Australian humpback whales reach 90% of their adult body length by roughly six to seven years of age and attain lengths of approximately 10.9 meters by age five, demonstrating a much faster growth rate than previously thought.
Key Distinction/Mechanism: Instead of relying on historical measurements from the mid-20th century commercial whaling era, researchers used non-invasive drone photogrammetry to precisely measure living whales, capturing data directly from newborns, juveniles, and adults.
Major Frameworks/Components:
- Drone Photogrammetry: The use of aerial drone imagery to non-invasively measure the body length and proportions of 865 individually identified whales between 2021 and 2024.
- Contemporary Growth Curves: The development of updated mathematical models describing the age-to-length relationship in living Eastern Australian humpback populations, establishing that growth is most rapid early in life before slowing as the animal approaches its maximum size.
- Photo-Identification Records: Combining long-term photographic records of individual whales to accurately determine age and track longitudinal growth.
Branch of Science: Marine Biology, Zoology
Future Application: The newly established contemporary growth curves provide a critical biological baseline. Future monitoring will use these curves to assess how whale health, growth, and reproductive timing respond to changing environmental conditions, such as shifting ocean temperatures or prey availability.
Why It Matters: Eastern Australian humpbacks are a major conservation success story. Understanding their exact growth metrics helps determine the population's overall biological health, energy requirements, and long-term viability in a changing climate.
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| PhD Candidate Stephanie Stack. Photo Credit: Courtesy of Griffith University |
Eastern Australian humpback whales reach nearly their full adult size remarkably quickly, a new Griffith University-led study has found, as shown by the first contemporary growth curves for this recovering whale population.
Published in Marine Mammal Science, the study combined drone-based aerial measurements with long-term photo-identification records to track growth across hundreds of whales, ranging from newborn calves to adults more than forty years old.
The research, led by Griffith University PhD candidate Stephanie Stack in collaboration with the Pacific Whale Foundation in Hervey Bay, found eastern Australian humpback whales reached approximately 10.9 meters in length by the age of five and attained 90 percent of their adult body length by about six to seven years of age.
Ms. Stack said the findings suggested eastern Australian humpback whales grew faster than other humpback whale populations studied elsewhere in the world.
“This is faster growth than other humpback whale populations that have been measured,” she said.
“These are also the first contemporary growth curves developed for eastern Australian humpback whales using measurements from living animals, updating knowledge that has relied heavily on measurements collected during the commercial whaling era in the mid-twentieth century.
“These new growth curves establish a baseline for investigating how whale biology may respond to changing environmental conditions.”
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| Photo Credit: Photo Credit: Courtesy of Griffith University |
Researchers collected measurements from 865 individually identified whales between 2021 and 2024 using noninvasive drone photogrammetry.
The dataset included calves, juveniles, and adults, allowing growth during the important early years of life to be measured directly rather than inferred from older animals.
The study found growth was most rapid during early life before gradually slowing as whales approached their maximum adult size.
PhD candidate Stephanie Stack
The new results aligned with historical estimates of adult body size from Australia, suggesting humpback whales have maintained similar adult lengths despite decades of population recovery and environmental change.
Eastern Australian humpback whales are recognized as one of the world’s most successful whale conservation stories, having recovered dramatically since the end of commercial whaling.
Ms. Stack added the new growth curves provided an important benchmark for future monitoring of whale populations, and helped scientists investigate how humpbacks responded to changing ocean conditions.
“As environmental conditions continue to change, having robust biological benchmarks like these will be essential for understanding how whale populations are responding,” she said.
Ms. Stack’s PhD research formed an important contribution to long-term monitoring of Southern Hemisphere humpback whales under the Humpback Whale Sentinel Program.
Published in journal: Marine Mammal Science
Authors: S. H. Stack, T. Fettermann, B. McGovern, and S. M. Bengtson Nash
Source/Credit: Griffith University | Carley Rosengreen
Edited by: Scientific Frontline
Reference Number: mb102326_01
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