[MARMAM] New publication - Oregon whales

[solene . derville]

Dear MARMAM community, 

We are pleased to announce the publication of our study of rorqual whale 
distribution and phenology off the coast of Oregon. 
This publication is part of the OPAL project (for more details see: [ 
https://mmi.oregonstate.edu/gemm-lab/opal-overlap-predictions-about-large-whales-identifying-co-occurrence-between-whales
 | 
https://mmi.oregonstate.edu/gemm-lab/opal-overlap-predictions-about-large-whales-identifying-co-occurrence-between-whales
 ] ) 

Derville S, Barlow DR, Hayslip C and Torres LG (2022) Seasonal, Annual, and 
Decadal Distribution of Three Rorqual Whale Species Relative to Dynamic Ocean 
Conditions Off Oregon, USA. Front. Mar. Sci. 9:868566. doi: 
10.3389/fmars.2022.868566 

Available on open-access: [ 
https://www.frontiersin.org/articles/10.3389/fmars.2022.868566/full | 
https://www.frontiersin.org/articles/10.3389/fmars.2022.868566/full ] 

Abstract: Whale populations recovering from historical whaling are particularly 
vulnerable to incidental mortality and disturbance caused by growing ocean 
industrialization. Several distinct populations of rorqual whales (including 
humpback, blue, and fin whales) migrate and feed off the coast of Oregon, USA 
where spatial overlap with human activities are on the rise. Effective 
mitigation of conflicts requires better foundational understanding of spatial 
and temporal habitat use patterns to inform conservation management. Based on a 
year-round, multi-platform distance sampling dataset (2016-2021, 177 survey 
days, 754 groups observed), this study generated density models to describe and 
predict seasonal distribution of rorqual whales in Oregon. Phenology analysis 
of sightings revealed a peak of humpback whale and blue whale density over the 
Oregon continental shelf in August and September respectively, and higher fin 
whale density in the winter (December). Additionally, we compared rorqual 
sighting rates across three decades of survey effort (since 1989) and 
demonstrate that rorqual whales are strikingly more prevalent in the current 
dataset, including distinct increases of blue and fin whales. Finally, density 
surface models relating whale densities to static and dynamic environmental 
variables acquired from data-assimilative ocean models revealed that summer and 
spring rorqual distribution were influenced by dynamic oceanographic features 
indicative of active upwelling and frontal zones (respectively 27% and 40% 
deviance explained). On the continental shelf, blue whales were predicted to 
occur closer to shore than humpback whales and in the more southern waters off 
Oregon. Summer and spring rorqual models, and humpback whale models, showed 
predictive performance suitable for management purposes, assessed through 
internal cross-validation and comparison to an external dataset (388 groups 
observed). Indeed, monthly hotspots of high predicted rorqual whale density 
across multiple years were validated by independent sightings (80% overlap in 
the summer model). These predictive models lay a robust basis for fine-scale 
dynamic spatial management to reduce impacts of human activities on endangered 
populations of rorqual whales in Oregon. 

Best, 


-- 
Solène Derville (she/her) 
PhD - Marine & Geospatial Ecology 
-- 
101 Promenade Roger Laroque, BPA5 
98848 Noumea cedex, New Caledonia 
Phone: +687 912299 
https://www.researchgate.net/profile/Solene_Derville 

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[MARMAM] New publication

[solene . derville]

Dear MARMAM community, 

We are pleased to announce the publication of our new dugong study in 
Scientific Reports (open access): 

Derville, S., Cleguer, C. & Garrigue, C. Ecoregional and temporal dynamics of 
dugong habitat use in a complex coral reef lagoon ecosystem. Sci Rep 12, 552 
(2022). [ https://doi.org/10.1038/s41598-021-04412-3 | 
https://doi.org/10.1038/s41598-021-04412-3 ] 

[ https://www.nature.com/articles/s41598-021-04412-3 | 
https://www.nature.com/articles/s41598-021-04412-3 ] 

Abstract: Mobile marine species display complex and nonstationary habitat use 
patterns that require understanding to design effective management measures. In 
this study, the spatio-temporal habitat use dynamics of the vulnerable dugong ( 
Dugong dugon ) were modelled from 16 satellite-tagged individuals in the coral 
reef lagoonal ecosystems of New Caledonia, South Pacific. Dugong residence time 
was calculated along the interpolated tracks (9371 hourly positions) to 
estimate intensity of use in three contrasting ecoregions, previously 
identified through hierarchical clustering of lagoon topographic 
characteristics. Across ecoregions, differences were identified in dugong 
spatial intensity of use of shallow waters, deeper lagoon waters and the 
fore-reef shelf outside the barrier reef. Maps of dugong intensity of use were 
predicted from these ecological relationships and validated with spatial 
density estimates derived from aerial surveys conducted for population 
assessment. While high correlation was found between the two datasets, our 
study extended the spatial patterns of dugong distribution obtained from aerial 
surveys across the diel cycle, especially in shallow waters preferentially used 
by dugongs at night/dusk during high tide. This study has important 
implications for dugong conservation and illustrates the potential benefits of 
satellite tracking and dynamic habitat use modelling to inform spatial 
management of elusive and mobile marine mammals. 

Best, 


-- 
Solène Derville (she/her) 
PhD - Marine & Geospatial Ecology 
-- 
101 Promenade Roger Laroque, BPA5 
98848 Noumea cedex, New Caledonia 
Phone: +687 912299 
https://www.researchgate.net/profile/Solene_Derville 
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[MARMAM] New publication - humpback whale telemetry

[solene . derville]

Dear MARMAM community, 

We are pleased to announce the publication of the following article in 
Scientific Reports: 

Derville, Solène, Leigh G Torres, Alexandre N Zerbini, Marc Oremus, and Claire 
Garrigue. 2020. “Horizontal and Vertical Movements of Humpback Whales Inform 
the Use of Critical Pelagic Habitats in the Western South Pacific.” Scientific 
Reports 10:4871 
[ https://www.nature.com/articles/s41598-020-61771-z | 
https://www.nature.com/articles/s41598-020-61771-z ] 

Abstract 

Humpback whales ( Megaptera novaeangliae ) are known for their nearshore 
distribution during the breeding season, but their pelagic habitat use patterns 
remain mostly unexplored. From 2016 to 2018, 18 humpback whales were equipped 
with depth-recording satellite tags (SPLASH10) to shed light on environmental 
and social drivers of seamount association around New Caledonia in the western 
South Pacific. Movement paths were spatially structured around shallow 
seamounts (<200 m). Indeed, two males stopped over the Lord Howe seamount chain 
during the first-ever recorded longitudinal transit between New Caledonia and 
the east coast of Australia. Residence time significantly increased with 
proximity to shallow seamounts, while dive depth increased in the vicinity of 
seafloor ridges. Most of the 7,986 recorded dives occurred above 80 m (88.5%), 
but deep dives (>80 m, max 616 m) were also recorded (11.5%), including by 
maternal females. Deep dives often occurred in series and were characterized by 
U-shapes suggesting high energy expenditure. This study provides new insights 
into the formerly overlooked use of pelagic habitats by humpback whales during 
the breeding season. Given increasing anthropogenic threats on deep sea 
habitats worldwide, this work has implications for the conservation of 
vulnerable marine ecosystems. 

The article can be downloaded in open access. 

Best wishes, 

-- 
Solène Derville 
PhD - Marine & Geospatial Ecology 
Association Opération Cétacés 
UMR Entropie - Institut de Recherche pour le Développement 
-- 
101 Promenade Roger Laroque, BPA5 
98848 Noumea cedex, New Caledonia 
Phone: +687 912299 
https://www.researchgate.net/profile/Solene_Derville 
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[MARMAM] New publication in Scientific Reports

[solene . derville]

Dear MARMAM community 

We are pleased to announce the publication of our new article about humpback 
whale use of seamounts in the South Pacific. 

Derville, S., Torres, L.G., Zerbini, A.N. et al. Horizontal and vertical 
movements of humpback whales inform the use of critical pelagic habitats in the 
western South Pacific. Sci Rep 10, 4871 (2020). [ 
https://doi.org/10.1038/s41598-020-61771-z | 
https://doi.org/10.1038/s41598-020-61771-z ] 

Abstract: Humpback whales ( Megaptera novaeangliae ) are known for their 
nearshore distribution during the breeding season, but their pelagic habitat 
use patterns remain mostly unexplored. From 2016 to 2018, 18 humpback whales 
were equipped with depth-recording satellite tags (SPLASH10) to shed light on 
environmental and social drivers of seamount association around New Caledonia 
in the western South Pacific. Movement paths were spatially structured around 
shallow seamounts (<200 m). Indeed, two males stopped over the Lord Howe 
seamount chain during the first-ever recorded longitudinal transit between New 
Caledonia and the east coast of Australia. Residence time significantly 
increased with proximity to shallow seamounts, while dive depth increased in 
the vicinity of seafloor ridges. Most of the 7,986 recorded dives occurred 
above 80 m (88.5%), but deep dives (>80 m, max 616 m) were also recorded 
(11.5%), including by maternal females. Deep dives often occurred in series and 
were characterized by U-shapes suggesting high energy expenditure. This study 
provides new insights into the formerly overlooked use of pelagic habitats by 
humpback whales during the breeding season. Given increasing anthropogenic 
threats on deep sea habitats worldwide, this work has implications for the 
conservation of vulnerable marine ecosystems. 

The article is open access in Scientific Reports. Please do not hesitate to get 
in touch with us if you have any questions (s.dervi...@live.fr or [ 
mailto:claire.garri...@ird.fr | claire.garri...@ird.fr ] ). 

-- 
Solène Derville 
PhD - Marine & Geospatial Ecology 
Association Opération Cétacés 
UMR Entropie - Institut de Recherche pour le Développement 
-- 
101 Promenade Roger Laroque, BPA5 
98848 Noumea cedex, New Caledonia 
Phone: +687 912299 
https://www.researchgate.net/profile/Solene_Derville 
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[MARMAM] New publication: Whales in warming water

[solene derville]

Dear MARMAM community,

We are pleased to announce the publication of the following article in 
Global Change Biology:


*Derville, S., Torres, L.G., Albertson, R., Andrews, O., Baker, C.S., 
Carzon, P., Constantine, R., Donoghue, M., Dutheil, C., Gannier, A., 
Oremus, M., Poole, M.M., Robbins, J. & Garrigue, C. (2019) Whales in 
warming water : Assessing breeding habitat diversity and adaptability in 
Oceania ’ s changing climate. Global Change Biology, 1–16. 
https://doi.org/10./gcb.14563*



Abstract

In the context of a changing climate, understanding the environmental 
drivers of marine megafauna distribution is important for conservation 
success. The extent of humpback whale breeding habitats and the impact 
of temperature variation on their availability are both unknown. We used 
19 years of dedicated survey data from seven countries and territories 
of Oceania (1,376 survey days), to investigate humpback whale breeding 
habitat diversity and adaptability to climate change. At a fine scale (1 
km resolution), seabed topography was identified as an important 
influence on humpback whale distribution. The shallowest waters close to 
shore or in lagoons were favored, although humpback whales also showed 
flexible habitat use patterns with respect to shallow offshore features 
such as seamounts. At a coarse scale (1° resolution), humpback whale 
breeding habitats in Oceania spanned a thermal range of 22.3–27.8°C in 
August, with interannual variation up to 2.0°C. Within this range, both 
fine and coarse scale analyses of humpback whale distribution suggested 
local responses to temperature. Notably, the most detailed dataset was 
available from New Caledonia (774 survey days, 1996–2017), where 
encounter rates showed a negative relationship to sea surface 
temperature, but were not related to the El Niño Southern Oscillation or 
the Antarctic Oscillation from previous summer, a proxy for feeding 
conditions that may impact breeding patterns. Many breeding sites that 
are currently occupied are predicted to become unsuitably warm for this 
species (>28°C) by the end of the 21st century. Based on modeled 
ecological relationships, there are suitable habitats for relocation in 
archipelagos and seamounts of southern Oceania. Although distribution 
shifts might be restrained by philopatry, the apparent plasticity of 
humpback whale habitat use patterns and the extent of suitable habitats 
support an adaptive capacity to ocean warming in Oceania breeding grounds.



The paper may be downloaded on 
https://onlinelibrary.wiley.com/doi/full/10./gcb.14563
Feel free to contact me directly for a PDF copy: solene.dervi...@ird.fr 



Best,

--
Solène Derville
PhD - Marine & Geospatial Ecology
Association Opération Cétacés
UMR Entropie - Institut de Recherche pour le Développement
--
101 Promenade Roger Laroque, BPA5
98848 Noumea cedex, New Caledonia
Phone: +687 912299
https://www.researchgate.net/profile/Solene_Derville

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[MARMAM] New publication: Comparative cetacean distribution models

[solene derville]

Dear MARMAM community,

We are pleased to announce the publication of the following article in 
Diversity and Distributions:


*Derville S, Torres LG, Iovan C, Garrigue C. Finding the right fit: 
Comparative cetacean distribution models using multiple data sources and 
statistical approaches. Divers Distrib. 2018;00:1–17. 
https://doi.org/10./ddi.12782*


***Abstract***
*Aim. *Accurate predictions of cetacean distributions are essential to 
their conservation but are limited by statistical challenges and a 
paucity of data. This study aimed at comparing the capacity of various 
statistical algorithms to deal with biases commonly found in 
nonsystematic cetacean surveys and to evaluate the potential for citizen 
science data to improve habitat modelling and predictions. An endangered 
population of humpback whales (Megaptera novaeangliae) in their breeding 
ground was used as a case study.

*Location.* New Caledonia, Oceania.
*Methods. *Five statistical algorithms were used to model the habitat 
preferences of humpback whales from 1,360 sightings collected over 14 
years of nonsystematic research surveys. Three different background 
sampling approaches were tested when developing models from 625 
crowdsourced sightings to assess methods accounting for citizen science 
spatial sampling bias. Model evaluation was conducted through 
cross‐validation and prediction to an independent satellite tracking 
dataset.
*Results.* Algorithms differed in complexity of the environmental 
relationships modelled, ecological interpretability and transferability. 
While parameter tuning had a great effect on model performances, GLMs 
generally had low predictive performance, SVMs were particularly hard to 
interpret, and BRTs had high descriptive power but showed signs of 
overfitting. MAXENT and especially GAMs provided a valuable complexity 
trade‐off, accurate predictions and were ecologically intelligible. 
Models showed that humpback whales favoured cool (22–23°C) and shallow 
waters (0–100 m deep) in coastal as well as offshore areas. Citizen 
science models converged with research survey models, specifically when 
accounting for spatial sampling bias.
*Main conclusions.* Marine megafauna distribution models present 
specific challenges that may be addressed through integrative 
evaluation, independent testing and appropriately tuned statistical 
algorithms. Specifically, controlling overfitting is a priority when 
predicting cetacean distributions for large‐scale conservation 
perspectives. Citizen science data appear to be a powerful tool to 
describe cetacean habitat.


The paper may be downloaded on 
https://onlinelibrary.wiley.com/doi/abs/10./ddi.12782
Feel free to contact me directly for a PDF copy: solene.dervi...@ird.fr 



Best,

--
Solène Derville
PhD student - Spatial Ecology
UMR Entropie - Institut de Recherche pour le Développement
Université Pierre et Marie Curie
Association Opération Cétacés
--
101 Promenade Roger Laroque, BPA5
98848 Noumea cedex, New Caledonia
Phone: +687 912299
https://www.researchgate.net/profile/Solene_Derville

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[MARMAM] New Publication: Social segregation of humpback whales

[solene derville]

Dear Marmam community,

We are pleased to announce the publication of the following article in the 
Journal of Mammalogy:

Solène Derville, Leigh G Torres, Claire Garrigue;*Social segregation of humpback whales in contrasted coastal and oceanic 
breeding habitats*,/Journal of Mammalogy/, , gyx185,https://doi.org/10.1093/jmammal/gyx185


Abstract: Maternal habitat preferences of humpback whales (Megaptera 
novaeangliae) are well documented from decades of coastal research but oceanic 
areas have received less attention. Whales breeding in New Caledonia occupy 
both ecosystems: a coastal reef complex (South Lagoon) and oceanic seamounts 
(Southern Seamounts). Generalized additive models were applied to 20 years of 
boat-based whale observations (n = 1,526) to describe habitat preferences and 
permissive home range estimations were used to explicitly model spatial 
segregation in relation to social context. Groups with calves (n = 206) 
preferred shallow coastal waters throughout the season in the South Lagoon, 
whereas no habitat segregation was observed between groups with (n = 74) and 
without calves (n = 140) in the Southern Seamounts. As a result, spatial 
overlap between groups with and without calves was more common in the Southern 
Seamounts than the South Lagoon. Despite a lack of social segregation around 
seamounts, mother-calf pairs were proportionally more frequent in the Southern 
Seamounts (27%) than in the South Lagoon (16%). Photographs of the calves’ 
dorsal flanks were analyzed to compare age and ecological markers across sites. 
Calves appeared older in the Southern Seamounts than in the South Lagoon but no 
difference in scarring or shark bites was found across sites, suggesting that 
calves experienced similar lifestyles and may move between offshore and coastal 
waters during the breeding season. This study highlights the flexible 
habitat-use patterns of breeding humpback whales and raises new questions about 
the environmental and social drivers of their presence in offshore breeding 
grounds.

The paper may be downloaded on 
https://academic.oup.com/jmammal/advance-article/doi/10.1093/jmammal/gyx185/4820410

Feel free to contact me directly for a PDF copy: solene.dervi...@ird.fr

Best,

--
Solène Derville
PhD student - Spatial Ecology
UMR Entropie - Institut de Recherche pour le Développement
Université Pierre et Marie Curie
Association Opération Cétacés
--
101 Promenade Roger Laroque, BPA5
98848 Noumea cedex, New Caledonia
Phone: +687 912299
https://www.researchgate.net/profile/Solene_Derville

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