Research
JERVIS BAY: AN AREA OF SIGNIFICANCE FOR SOUTHWARD MIGRATING HUMPBACK WHALE COW/CALF PAIRS?
Introduction In the southern hemisphere, the east Australian population of humpback whales (Megaptera novaeangliae) has shown a significant increase in growth over the last decade.
Their current range has expanded with sightings now recorded in areas where humpback whales had previously been limited, due to a vast history of intense whaling efforts in the early 20th century along the Australian coastline, including Jervis Bay.
Humpback whales of Jervis Bay
Jervis Bay is one of a few east coast locations that witness both the northern and southern migrations, as humpback whales follow the near shore migration corridors that provide whales with protection from rough seas, predators and conspecifics.
Distribution patterns of migrating humpback whales (Megaptera novaeangliae) in Jervis Bay, Australia: A spatial analysis using geographical citizen science data
Eleanor Bruce a, b,*, Lindsey Albright a, Scott Sheehan c, Michelle Blewitt b,c
a Geocoastal Research Group, School of Geosciences, University of Sydney, Madsen Building F09, 2006, NSW, Australia
b University of Sydney Institute of Marine Science (USIMS), University of Sydney, Australiac Marine Mammal Research, PO Box 117 Huskisson, Jervis Bay, NSW, 2540, Australia
A b s t r a c t
Increases in east Australian humpback whale populations, specifically in areas where sightings were previously infrequent, highlight the importance of understanding the usage patterns and habitat preferences for resting grounds along migration pathways. This study investigates the spatio-temporal distribution of humpback whales in Jervis Bay, Australia, based on pod composition, providing insight on the role of this shallow coastal embayment for mother-calf pods during the southern migration to polar feeding grounds. Geographical citizen science-based sighting data, collected from a commercial whale-watch platform during the 2007-2010 migration seasons, were used to examine variations in bay usage and pod composition. Differences in the distribution patterns of mother-calf and non-calf pod sightings were examined using spatial cluster analysis. The impact of sampling bias, introduced through non-specialist volunteer collected data, on spatial cluster detection was simulated. Observation error and spatial sampling bias may affect local spatial cluster detection. Sampling processes with potential to contribute to this bias should be recorded in the survey design of geographical citizen science based data collection programmes. Mother-calf pods showed a significant preference for the shallow waters of Jervis Bay during October and November, indicating the bay may function as a preferred resting location during their southern migration with important marine management implications.
