Aloha colleagues,
My coauthors and I would like to share with you a paper
recently published in the journal Frontiers in Marine Science
titled "The occurrence of humpback whales across the Hawaiian
archipelago revealed by fixed and mobile acoustic monitoring." The
paper is presents new findings about humpback whale presence
across the archipelago. it is open access and can be obtained for
free through Frontiers in Marine Science.
Lammers MO, Goodwin B, Kügler A, Zang EJ, Harvey M, Margolina
T, Martinez JA, Merkens K and Hatch LT (2023) The occurrence of
humpback whales across the Hawaiian archipelago revealed by fixed
and mobile acoustic monitoring. Front. Mar. Sci. 10:1083583. doi:
10.3389/fmars.2023.1083583
The occurrence of
humpback whales (Megaptera novaeangliae) across
the 2600 km of Hawaiian archipelago, which include the remote
atolls, banks,
and seamounts of Papahānaumokuākea Marine National Monument
(PMNM), remains
poorly understood. Previous surveys for humpback whales beyond
the main
Hawaiian Islands have been scarce due to limited access and
the challenging
winter conditions typically found in PMNM when whales are
present. To overcome these
limitations, a combination of moored acoustic recorders and a
Wave Glider
autonomous surface vehicle were used to acoustically monitor
eight locations and
survey approximately 1500 km of the Hawaiian archipelago for
the occurrence of
humpback whale song during the 2019-2020 breeding season.
Relative song prevalence was established
using a machine learning tool and by quantifying the level of
song chorusing. A
generalized additive model framework was applied to understand
the associations
between habitat variables and humpback whale song occurrence,
and sound
propagation modeling was performed to examine whether acoustic
propagation
influenced observed patterns. Whale song was recorded at all
monitored and
surveyed locations across the archipelago, albeit in varying
amounts. Among the
locations monitored with moored recorders, the highest and
most sustained
seasonal chorusing levels were measured off Maui followed by
French Frigate
Shoals (Kānemilohaʻi), Hawaiʻi Island, Middle Bank, Oʻahu,
Kauaʻi, Gardner
Pinnacles (Pūhāhonu) and Pearl and Hermes Reef (Holoikauaua),
respectively. The
Wave Glider mission to PMNM revealed that song prevalence was
highest at Middle
Bank and gradually decreased further to the northwest,
reaching a minimum at
Gardner Pinnacles (Pūhāhonu). However, song occurrence
increased again at Raita
Bank, remaining high between Raita Bank and the Northampton
Seamounts. The
results reveal that nearly the entire Hawaiian archipelago is
exploited by
humpback whales during the winter and early spring months.
Moreover, song
occurrence patterns suggest that there may be more structure
in the
distribution of whales in PMNM than previously known and
raises questions about
whether multiple subpopulations occur across the archipelago.
Best wishes,
Marc
--
Marc O. Lammers, PhD
Research Ecologist | Hawaiian Islands Humpback Whale National
Marine Sanctuary
726 S. Kihei Rd. | Kihei, HI 96753 | Ph: +1-808-419-7211 |
marc.lammers@noaa.gov
--------
Affiliate Faculty | Hawaii Institute of Marine Biology
46-007 Lilipuna Rd. | Kaneohe, HI 96744 | Ph: +1-808-375-0010 |
lammers@hawaii.edu