[MARMAM] NEW PAPER: The most southerly occurrence of humpback whales in the western Weddell Sea

[Angus Henderson]

NEW PAPER: The most southerly occurrence of humpback whales in the western
Weddell Sea

Available free here: https://doi.org/10./mms.13033

Globally, warming oceans are causing marine species to shift poleward
(Melbourne-Thomas et al., 2022
).
The Antarctic Peninsula is a global hotspot for human-induced warming
(Jones et al., 2019
;
Turner et al., 2020
),
evidenced by lessening sea ice conditions (Kumar et al., 2021
),
warming oceans, and the collapse of ice shelves (Etourneau et al., 2019
).
Here,
we detail two new record-breaking sightings of humpback whales in the
western WS. Both sightings were made from ice-breaker class tourist
vessels, which were able to access southerly regions of the western WS
during a summer with a new record low in sea ice extent (February 23, 2022;
Raphael & Handcock, 2022
)
and the now regular breakup of the Larsen A & B ice shelves (Wang et al.,
2022
). The
novel humpback whale sightings were made on December 8 at 1230 UTC (ship's
position: 64.83°S, 59.15°W) and on January 26 at 0944 UTC (ship's position:
65.31°S, 58.98°W) 30 and 90 nmi (56 and 167 km) further south than any
previously reported humpback whale sighting in the western WS (Figure 1
).
Humpback
whales respond to dynamic environmental features (Thiele et al., 2004
)
which likely drive preferred prey aggregations (Herr et al., 2016
;
Santora et al., 2010
)
and thus will likely be able to continue to respond to new extremes in sea
ice conditions like the more regular opening of the western WS (Jena et
al., 2022
).
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[MARMAM] NEW PAPER: Assessing the viability of estimating baleen whale abundance from tourist vessels

[Angus Henderson]

NEW PAPER: Assessing the viability of estimating baleen whale abundance from 
tourist vessels

Angus Fleetwood Henderson, Mark Andrew Hindell,  Simon Wotherspoon , Martin 
Biuw, Mary-Anne Lea, Nat Kelly and Andrew Damon Lowther

Freely available at frontiersin.org/articles/10.3389/fmars.2023.1048869/full

This paper details viability of using tourist vessels to determine baleen whale 
abundance in the southwest Atlantic sector of the Southern Ocean. Thanks to all 
that made this paper possible, and are continuing to make the work possible.

ABSTRACT : Many populations of southern hemisphere baleen whales are recovering 
and are again becoming dominant consumers in the Southern Ocean. Key to 
understanding the present and future role of baleen whales in Southern Ocean 
ecosystems is determining their abundance on foraging grounds. Distance 
sampling is the standard method for estimating baleen whale abundance but 
requires specific logistic requirements which are rarely achieved in the remote 
Southern Ocean. We explore the potential use of tourist vessel-based sampling 
as a cost-effective solution for conducting distance sampling surveys for 
baleen whales in the Southern Ocean. We used a dataset of tourist vessel 
locations from the southwest Atlantic sector of the Southern Ocean and 
published knowledge from Southern Ocean sighting surveys to determine the 
number of tourist vessel voyages required for robust abundance estimates. 
Second, we simulated the abundance and distributions of four baleen whale 
species for the study area and sampled them with both standardized line 
transect surveys and non-standardized tourist vessel-based surveys, then 
compared modeled abundance and distributions from each survey to the original 
simulation. For the southwest Atlantic, we show that 12-22 tourist vessel 
voyages are likely required to estimate abundance for humpback and fin whales, 
with relative estimates for blue, sei, Antarctic minke, and southern right 
whales. Second, we show tourist vessel-based surveys outperformed standardized 
line transect surveys at reproducing simulated baleen whale abundances and 
distribution. These analyses suggest tourist vessel-based surveys are a viable 
method for estimating baleen whale abundance in remote regions. For the 
southwest Atlantic, the relatively cost-effective nature of tourist 
vessel-based survey and regularity of tourist vessel voyages could allow for 
annual and intra-annual estimates of abundance, a fundamental improvement on 
current methods, which may capture spatiotemporal trends in baleen whale 
movements on forging grounds. Comparative modeling of sampling methods provided 
insights into the behavior of general additive model-based abundance modeling, 
contributing to the development of detailed guidelines of best practices for 
these approaches. Through successful engagement with tourist company partners, 
this method has the potential to characterize abundance across a variety of 
marine species and spaces globally, and deliver high-quality scientific 
outcomes relevant to management organizations.


Angus Henderson (he/him)
PhD Candidate
Marine Predator Lab | IMAS | UTAS

Recent papers:
Henderson, A.F., McMahon C.R., Harcourt R., Guinet C., Picard B., Wotherspoon 
S., Hindell M. A.,.
"Inferring variation in southern elephant seal at-sea mortality by modelling 
tag failure."
Frontiers in Marine Science (2020).
https://doi.org/10.3389/fmars.2020.517901



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Re: [MARMAM] Seeking MMOs for deployment on expedition tour vessels in the Antarctic Peninsula

[Angus Henderson]

RE: Seeking MMOs for deployment on expedition tour vessels in the Antarctic
Peninsula.

To all those that applied to these previously advertised positions, thank
you for your application, we were overwhelmed with interest in these
positions. These positions are now filled, however, there are still some
applicants to be contacted as we work through the process. This message to
notify interested parties that applications have now closed. The exception
remains those applicants from Argentina or Chile. If you are a resident of
Argentina or Chile, please put through your application.

Cheers,

Angus
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[MARMAM] Seeking MMOs for deployment on expedition tour vessels in the Antarctic Peninsula.

[Angus Henderson]

These positions are unpaid at this stage, however, all travel to and from
departure locations, food and accommodation costs will be covered.
Deployments are across the Antarctic summer period, for a period of 8-12
weeks (further details below).



*Brief Background*



Representing the most rapidly warming region of Antarctica, the western
Antarctic Peninsula (WAP) has a rapidly growing tourist industry and krill
fishery (Bender et al., 2016; Schumann et al., 2013; Spence et al., 2017).
Its ecological significance has been recognised internationally and is the
focus of efforts to establish a Marine Protected Area. As many species
recover from past exploitation, it is important to understand the patterns
of distribution and relative abundance of marine predators on regional
scales. While considerable effort has been expended on understanding key
land-based krill predators such as penguins and seals (e.g., Boyd, 2002),
there has been wide acknowledgement that information on the temporal and
spatial distribution and abundance of cetaceans and other marine mammals
not amenable to land-based study is lacking (IWC Report 2019). Antarctic
whale stocks were hunted to commercial extinction in 20th century (Rocha et
al., 2014) and are understood to be recovering variably (e.g., for humpback
whales, *see* Constantine et al., 2014; Fleming and Jackson, 2011; Noad et
al., 2019; Olavarría et al., 2007). Yet relatively little is known of the
abundance and distribution of baleen whales in the Southern Ocean foraging
grounds.

Distance sampling sets a gold standard for estimating marine mammal
abundance and distribution (Williams et al., 2006). Yet broad-scale
distance sampling surveys are prohibitively expensive in remote Southern
Ocean waters and often produces only one survey estimate per season, that
is subsequently used to characterise the entirety of that season. With
commitments from several Antarctic tour operators, we set out to build on
the pilot survey program initiated during the 2019-2020 season by
standardising a scientifically peer-reviewed distance sampling protocol for
estimation of at-sea cetacean abundance and distribution.



Specific Aims:

(i) Can platforms of opportunity-based distance sampling
efforts be improved and standardised in order to contribute to
understanding Southern Ocean cetacean status and trends.

(ii)What physical ocean properties, environmental variables
and/or krill predictors drive cetacean abundance and distribution at
temporal scales ranging from within-season to interannual.

(iii)  What is the total consumption rate of krill by baleen whales
relative to land-based krill predators and human krill harvest, and how
does this relate to what we know of krill abundance and distribution in
time and space?





*The roles*



We are seeking expressions of interest and commitments (where possible)
from volunteers with experience as marine mammal observers or those
interested in becoming one. This is your opportunity to be one of the very
few people in the world that go to Antarctica. You will have exposure to
the wealth of wildlife and stunning landscapes that make this part of the
Southern Ocean so special and the opportunity to ‘be a tourist’ at times
during the voyage (potentially including landings). Sets of two observers
(one trained/experienced lead MMO and one in training MMO) will be deployed
from Ushuaia and Punta Arenas on expedition tour vessel (200-500
passengers) across the Antarctic summer (Nov-March) in the 2021/22 and
2022/23 season. We are seeking a commitment of 8-12 weeks; this will
include several (3-6) voyages to the Antarctic Peninsula (potentially via
South Georgia, the Falkland islands/ Islas Malvinas and/or South Orkney
Islands), aboard tour vessels. Preference will be given to residents of
Chile and Argentina, and those in closer proximity to voyages departure
locations (Ushuaia and Punta Arenas).



Observers will take distance sampling measurements of whales and other
marine mammals from the bridge of the vessels. MMOs will need to remain
focused and on task for many hours, and at times work to weather windows
across an 18-hour day. It is critical MMOs are organised, focused, take
accurate field recording, and remain on task. Lead MMOs will be responsible
for dictating field effort in response to weather, ensuring quality control
and data management.



Both MMOs will also be required to give a seminar/lecture to guests on
board the vessel as part of our agreement in securing berths for observers.
MMOs will be required to complete a basic level of induction and training
(provided), including the study of marine mammals and birds of the
south-east Atlantic sector of the Southern Ocean.



*Requirements*

·  Professional attitude

·  Excellent verbal, written and interpersonal communication skills

·  Self-motivated with attention to detail

·  Must have the ability to conduct tasks independently

·  Ability