Brooks, L., Franklin, T., Franklin, W., Harrison, P., Corkeron, P., and Pollock, K.H. (2024). Humpback whales (Megaptera novaeangliae) in Hervey Bay, Australia: a stopover for females early in their southern migration. Frontiers in Marine Science 11.

In the Southern Hemisphere, humpback whales (Megaptera novaeangliae)

migrate along the extended continental coastlines of Australia, South America,

and South Africa. This study reports on photo-identi cation capture–recapture

data from a long-term survey conducted in Hervey Bay, Queensland, where a

substantial proportion of the population stop over early in the southern

migration. Photo-identi cation data were collected over 10 weeks per year

from 1997 to 2009. The migration through Hervey Bay is dominated and led

by females with high delity to the site. Mature females, yearlings, and immature

whales use the Bay during August, while mature lactating females with calves

dominate during September and October. Complex social behaviours occur

throughout the season and differ between the early and late cohorts. We argue

that the composition of the two cohorts and their distinctively different

behaviours indicate that Hervey Bay is not simply a resting site but an area of

aggregation that serves important social and biological bene ts. A multistate

open robust design model was tted to capture–recapture data to estimate the

annual number of whales visiting the Bay, the permanent emigration rate,

proportions of the visiting population that do not enter the Bay each year, the

number present during each week, and their residency times. The number of

annual visitors to the Bay increased approximately linearly from 857 in 1997 to

2175 at the end of sampling in 2009 with two-thirds migrating through during the

rst half of each season. The population rate of growth may have been slowing by

2009, but there was considerable uncertainty in the trajectory and little basis for

projection into the future. While it is desirable to know the current status of the

Hervey Bay population and what has occurred since 2009, the cost and effort

required make further manual collection and matching of images unlikely. The

development of AI algorithmic matching software may enable further research in future.

The paper is open access and availble to download here:

Humpback whales (Megaptera novaeangliae) in Hervey Bay, Australia: a stopover for females early in their southern migration frontiersin.org