A groundbreaking study led by international researchers, including experts from the University of Auckland's School of Biological Sciences, has revealed that the brutal legacy of commercial whaling continues to influence humpback whale behaviour even 50 years after its cessation. Published in the prestigious journal Current Biology on February 27, 2026, the research demonstrates how population recovery from near-extinction has shifted mating dynamics, with older males now dominating reproductive success.

Humpback whales (Megaptera novaeangliae), renowned for their acrobatic breaches and haunting songs, were decimated by whaling across the Southern Hemisphere. In the waters of Oceania—which span from New Caledonia to French Polynesia—the population plummeted to fewer than 200 individuals by the 1970s due to relentless hunting. This demographic bottleneck not only threatened their survival but also altered social structures, including how females select mates. As numbers rebound, scientists are uncovering how these historical traumas echo through generations.

🦭 The Devastating History of Whaling in Oceania

Commercial whaling peaked in the early 20th century, with humpback whales targeted for their oil, meat, and baleen. In Oceania, historical records indicate pre-whaling abundances exceeded 14,000 individuals, but by 1966, fewer than 360 remained—a 97% decline. New Zealand played a peripheral role, with shore-based stations and passing factory ships contributing to the slaughter, though primary grounds were Antarctic feeding areas and tropical breeding calving grounds like New Caledonia.

The 1963 international moratorium on Antarctic whaling and 1985 global ban allowed recovery. Today, Oceania's humpbacks number around 5,000-10,000, with annual increases of 10-12% in some stocks. Yet, the population remains vulnerable, facing ship strikes, fishing gear entanglements, and climate change impacts on krill prey.

• Pre-whaling estimate: >14,000 humpbacks in Oceania.
• 1970s low: <200 breeding females.
• Current trajectory: Recovering but not yet at carrying capacity.

This context underscores why University of Auckland (UoA) marine biologists are pivotal in tracking long-term recovery, contributing data crucial for IWC (International Whaling Commission) assessments.

Unpacking the UoA-Led Study: Methods and Innovations

The study, titled "Changes in age-related sexual selection in a humpback whale population recovering from exploitation," drew on 19 years of data (2000-2018) from New Caledonia's breeding grounds, collected by NGO Opération Cétacés. Researchers catalogued 1,606 whales, genotyping 962 males via skin biopsies for paternity and identity.

Key innovation: Epigenetic clocks—molecular age estimators from DNA methylation patterns in skin samples—aged 485 males with ~4.5-year precision. Behavioural observations spanned 1,717 encounters in seven contexts: singing (long-range attraction), solitary escorting (close female following), competitive groups (physical jostling), and more.

UoA's Dr Emma Carroll and Dr Ellen Garland provided expertise in genetics and acoustics, while Dr Luke Rendell (visiting) aided behavioural analysis. Paternity was assigned using 15 microsatellite loci, identifying 66 fathers for 79 calves.Explore research roles in marine biology at NZ universities.

Key Findings: From Youthful Breeding to Elder Dominance

During low abundance (2000-2008, ~562 whales), the population was young-skewed (left-skewed age pyramid). Younger males (9-23 years) sired disproportionately, buffering inbreeding—a survival adaptation post-bottleneck.

By 2009-2018 (higher abundance, ~1,291 whales), age structure evened out, with older males (≥23 years) over-represented in successful tactics: singing (p<0.001), solitary escorting (p<0.001), and paternity (63% simulations showed excess ≥23-year-old fathers). Mean paternal age rose; skew remained low (1.13-1.22), indicating broad success but age-graded.

• Low density: Relaxed age selection; young males ~equal chance.
• High density: Older males leverage experience/size for 70% competitive group paternity.
• Population mean age: 20.6 years; <1.5% >40 years.

"Whaling casts a very long shadow," notes UoA's Dr Emma Carroll. "Even 50 years later, the effects are still working their way through the population."

Photo by Jeroen van de Water on Unsplash

UoA's Pivotal Role in Global Whale Research

Waipapa Taumata Rau University of Auckland stands at the forefront of cetacean studies in the Pacific. The Marine Mammal Research Group collaborates internationally, leveraging NZ's strategic position for Southern Ocean monitoring. Dr Carroll's work on cultural evolution in whale songs and Dr Garland's on population genetics exemplifies UoA's impact.Discover university opportunities in New Zealand.

This study builds on prior UoA efforts, like Oceania humpback photo-ID catalogues, informing policy. For aspiring marine researchers, UoA offers PhD scholarships in ecology via scholarships and hands-on fieldwork.

Implications for Conservation and Genetic Diversity

The shift risks reducing genetic diversity if older males monopolize breeding, echoing bighorn sheep dynamics post-hunting. However, low skew suggests resilience. Climate change exacerbates pressures: warmer waters alter migration, prey, and breeding success.

Recommendations: Enhance long-term monitoring, reduce entanglements (NZ reports 20+ annually), and protect breeding grounds. IWC quotas and MPAs (Marine Protected Areas) are vital.Read UoA's full news release.

Broader Context: Whaling's Global Legacy

Similar patterns emerge elsewhere: North Atlantic humpbacks show age-biased success post-recovery. Fin whales in Pacific lost 99% effective population size. NZ's subantarctic right whales, hunted to ~50 females, recover slowly (~3% annually).

UoA contributes to global efforts, partnering with Oregon State and Curtin University. For students, career advice on marine research paths.

Stakeholder Perspectives: From NGOs to Policymakers

Opération Cétacés' Claire Garrigue praises the epigenetic tools: "Long-term data unlocks hidden dynamics." Dr Franca Eichenberger (St Andrews): "Continued monitoring is crucial." NZ DOC (Department of Conservation) uses such insights for threat management.

Photo by Jusdevoyage on Unsplash

• NGOs: Advocate expanded calving ground protections.
• Governments: Integrate into EEZ (Exclusive Economic Zone) plans.
• Academia: Calls for AI in photo-ID scaling.

Future Outlook: What Lies Ahead for Humpback Recovery

Projections: Oceania humpbacks could reach 15,000 by 2040 if threats abate. Challenges include ocean noise doubling migration stress. Solutions: Tech like passive acoustics, international treaties. UoA's upcoming projects on song evolution promise more revelations.

For researchers eyeing research assistant jobs, NZ unis offer prime fieldwork in pristine waters.

Actionable Insights for Marine Scientists and Students

1. Pursue epigenetic training—key for non-invasive ageing.
2. Contribute to citizen science: NZ Whale Watch apps.
3. Advocate policy: Support MPAs via petitions.
4. Explore careers: University jobs in NZ biology depts.

This UoA study exemplifies how higher education drives conservation, positioning NZ as a hub for cetacean excellence. Check Rate My Professor for UoA marine faculty insights, browse higher ed jobs, and access career advice.