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Occurence of fin whale (Balaenoptera physalus) in the Azores archipelago: assessment on its migration behavior and first photo-ID catalogue of the area.

Authors:
Biagio Violi at Menkab: il respiro del mare
Biagio Violi
  • Menkab: il respiro del mare
Rui Peres dos Santos at Centro de Ciências do Mar
Rui Peres dos Santos
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Abstract

The fin whale (Balaenoptera physalus) is one of the most abundant baleen species in Azorean waters. Here we present the first photographical identification (photo-ID) catalogue of this species that occur regularly across the waters of this area, particularly during the spring season. A six-year study, making use of the practice of whale watching, allowed the opportunity to collect new data on fin whale ecology. For each sighting, we collected data on behavior, geographical location, response to boat presence, and photo-ID. In a total of 488 sightings, 933 putative individuals were seen. The main observed behaviors were: travelling (48%) and foraging (29%). Considering the response to boat presence, individuals were largely indifferent (84%) and approached the vessel (11%). A total of 845 images used for photo-ID of porpoises were taken. All images were sorted according to quality criteria (from Q1 to Q5) and only images with a minimum quality of Q4 were used, generating a total of 420 photo-ID images. Through the photo-ID assessment: 214 different individuals were identified, 5 individuals were matched between years and the longest period in a year during which a whale stayed in the same area was 28 days. This first approach shows that fin whales are quite abundant in spring time during the migration from breeding to feeding grounds. Our data also confirm that the whale watching boat presence doesn’t affect the natural behavior of the species. Furthermore, it seems that the seasonal presence of krill in the area attract individuals on an annual basis. It is possible that the Azorean waters act as a corridor for baleen whales. We propose that further studies should focus on better understanding how baleen whales in general, and fin whales in particular, use oceanic islands during their migration.
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Occurrence of fin whale (
Balaenoptera physalus
)
in the Azores archipelago:
assessment on its migration behavior and
first photo-ID catalogue of the area.
Violi B.
violi.biagio@gmail.com
Fin whales are quite abundant in spring time during the migration from breeding to feeding grounds [1].
Our results confirm that Azorean waters act as a corridor for fin whales or baleen whales in general, above all
for travelling/foraging. This is probably a result of the spring bloom in the area [2]
It seems that do not exist a specific feeding ground, before they pursue northward migration.
Our data confirm that the whale watching boat presence doesn’t affect the natural behavior of the species.
A total of 214 different individuals were identified for the first fin whale Azorean Catalogue.
Biagio Violi1,2,3 & Rui Peres dos Santos1
Pictures were sorted following quality
criteria (from Q1 to Q5) and only images
with Q4 and Q5 quality were used,
generating a total of 420 photo-ID
images. We got:
•214 different identified individuals
•5 individuals rematched between years
•28 days the longest period in which a
whale traveled in the same area
RESULTS 2: Photo-ID catalogue
Figure 4. Photo-id catalogue : two individuals recaptured in the South waters of Pico island.
DATASET (from 2012 to 2017)
Obtained trough whale watching activities:
488 sightings
933 individuals
845 images taken for photo-ID
GPS and behavioral data
Why do fin whales across Azores waters?
What do they do?
Does whale watching activity affect their
normal behavior?
How many are they?
Figure 1. Map of Azores archipelago
Azores
•The main observed behaviors among different years were: (T) travelling 48% and (FO) foraging 29%.
•The response to boat presence were largely (I) indifferent 84% and (A) approaching the vessel 11%.
RESULTS 1: Observed behavior and response to the boat presence
Figure 2. Histograms showing data recorded in different years from 2012 to 2017: main behaviors (on the left) and the whale response to the whale watching boat presence (on the right).
0
10
20
30
40
50
60
FO TS TA M R TF SO BR LB SP FL H B NI
Percent of observed behavior (%)
Behaviors
Behavior around Azores waters
2012
2013
2014
2015
2016
2017
0
20
40
60
80
100
A I E
Percent of observed behavior (%)
Behaviors
Response to the boat presence
2012
2013
2014
2015
2016
2017
•Regarding the Sightings information it seems to
exist a specific area (south of Pico) for fin whale
sightings.
•On the analyses of the Encounter Rate, our data
show´s that it doesn't exist any specific ground for
fin whale observation.
Figure 3. Map of Sighitings and Encouter rate in the study area
Pico
Faial
Pico
Faial
1. FUTURISMO, Portas do Mar, Ponta Delgada, Azores, Portugal
2. Department of Earth, Environment & Life Sciences (DISTAV), Genoa University, Genoa, GE, Italy
3. MENKAB: il respiro del mare NGO, Savona, SV, Italy DA08
References. [1] Silva, M. A., Prieto, R., Jonsen, I., Baumgartner, M. F., & Santos, R. S. (2013). North Atlantic blue and fin whales suspend their spring migration to forage in middle latitudes: building up energy reserves for the journey?. PLoS
One, 8(10). [2] Visser, F., Hartman, K. L., Pierce, G. J., Valavanis, V. D., & Huisman, J. (2011). Timing of migratory baleen whales at the Azores in relation to the North Atlantic spring bloom. Marine Ecology Progress Series, 440, 267-279.
32st Annual Conference, European Cetacean Society 2018, La Spezia, Italy
ResearchGate has not been able to resolve any citations for this publication.
North Atlantic Blue and Fin Whales Suspend Their Spring Migration to Forage in Middle Latitudes: Building up Energy Reserves for the Journey?
Article
Full-text available
The need to balance energy reserves during migration is a critical factor for most long-distance migrants and an important determinant of migratory strategies in birds, insects and land mammals. Large baleen whales migrate annually between foraging and breeding sites, crossing vast ocean areas where food is seldom abundant. How whales respond to the demands and constraints of such long migrations remains unknown. We applied a behaviour discriminating hierarchical state-space model to the satellite tracking data of 12 fin whales and 3 blue whales tagged off the Azores, to investigate their movements, behaviour (transiting and area-restricted search, ARS) and daily activity cycles during the spring migration. Fin and blue whales remained at middle latitudes for prolonged periods, spending most of their time there in ARS behaviour. While near the Azores, fin whale ARS behaviour occurred within a restricted area, with a high degree of overlap among whales. There were noticeable behavioural differences along the migratory pathway of fin whales tracked to higher latitudes: ARS occurred only in the Azores and north of 56°N, whereas in between these areas whales travelled at higher overall speeds while maintaining a nearly direct trajectory. This suggests fin whales may alternate periods of active migration with periods of extended use of specific habitats along the migratory route. ARS behaviour in blue whales occurred over a much wider area as whales slowly progressed northwards. The tracks of these whales terminated still at middle latitudes, before any behavioural switch was detected. Fin whales exhibited behavioural-specific diel rhythms in swimming speed but these varied significantly between geographic areas, possibly due to differences in the day-night cycle across areas. Finally, we show a link between fin whales seen in the Azores and those summering in eastern Greenland-western Iceland along a migratory corridor located in central Atlantic waters.
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Timing of migratory baleen whales at the Azores in relation to the North Atlantic spring bloom
Article
Full-text available
  • Oct 2011
Each year, a phytoplankton spring bloom starts just north of the North Atlantic Subtropical Gyre, and then expands northwards across the entire North Atlantic. Here, we investigate whether the timing of the spring migration of baleen whales is related to the timing of the phytoplankton spring bloom, using 4 yr of dedicated whale observations at the Azores in combination with satellite data on ocean chlorophyll concentration. Peak abundances of blue whale Balaenoptera musculus, fin whale B. physalus, humpback whale Megaptera novaeangliae and sei whale B. borealis were recorded in April–May. The timing of their presence tracked the onset of the spring bloom with mean time lags of 13, 15, 15 and 16 wk, respectively, and was more strongly related to the onset of the spring bloom than to the actual time of year. Baleen whales were actively feeding on northern krill Meganyctiphanes norvegica in the area, and some photo-identified individuals stayed in Azorean waters for at least 17 d. Baleen whales were not observed in this area in autumn, during their southward migration, consistent with low chlorophyll concentrations during summer and autumn. Our results support the hypothesis that baleen whales track the secondary production generated by the North Atlantic spring bloom, utilizing mid-latitude areas such as the Azores as foraging areas en route towards their summer feeding grounds.
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