scholarly journals Satellite tracking reveals novel migratory patterns and the importance of seamounts for endangered South Pacific humpback whales

2015 ◽  
Vol 2 (11) ◽  
pp. 150489 ◽  
Author(s):  
Claire Garrigue ◽  
Phillip J. Clapham ◽  
Ygor Geyer ◽  
Amy S. Kennedy ◽  
Alexandre N. Zerbini

The humpback whale population of New Caledonia appears to display a novel migratory pattern characterized by multiple directions, long migratory paths and frequent pauses over seamounts and other shallow geographical features. Using satellite-monitored radio tags, we tracked 34 whales for between 5 and 110 days, travelling between 270 and 8540 km on their southward migration from a breeding ground in southern New Caledonia. Mean migration speed was 3.53±2.22 km h −1 , while movements within the breeding ground averaged 2.01±1.63 km h −1 . The tag data demonstrate that seamounts play an important role as offshore habitats for this species. Whales displayed an intensive use of oceanic seamounts both in the breeding season and on migration. Seamounts probably serve multiple and important roles as breeding locations, resting areas, navigational landmarks or even supplemental feeding grounds for this species, which can be viewed as a transient component of the seamount communities. Satellite telemetry suggests that seamounts represent an overlooked cryptic habitat for the species. The frequent use by humpback whales of such remote locations has important implications for conservation and management.

2009 ◽  
Vol 6 (3) ◽  
pp. 297-300 ◽  
Author(s):  
Roine Strandberg ◽  
Raymond H. G. Klaassen ◽  
Mikael Hake ◽  
Thomas Alerstam

We investigated the risk associated with crossing the Sahara Desert for migrating birds by evaluating more than 90 journeys across this desert by four species of raptors (osprey Pandion haliaetus , honey buzzard Pernis apivorus , marsh harrier Circus aeruginosus and Eurasian hobby Falco subbuteo ) recorded by satellite telemetry. Forty per cent of the crossings included events of aberrant behaviours, such as abrupt course changes, slow travel speeds, interruptions, aborted crossings followed by retreats from the desert and failed crossings due to death, indicating difficulties for the migrants. The mortality during the Sahara crossing was 31 per cent per crossing attempt for juveniles (first autumn migration), compared with only 2 per cent for adults (autumn and spring combined). Mortality associated with the Sahara passage made up a substantial fraction (up to about half for juveniles) of the total annual mortality, demonstrating that this passage has a profound influence on survival and fitness of migrants. Aberrant behaviours resulted in late arrival at the breeding grounds and an increased probability of breeding failure (carry-over effects). This study also demonstrates that satellite tracking can be a powerful method to reveal when and where birds are exposed to enhanced risk and mortality during their annual cycles.


2005 ◽  
Vol 272 (1572) ◽  
pp. 1547-1555 ◽  
Author(s):  
Michael C James ◽  
Ransom A Myers ◽  
C. Andrea Ottensmeyer

Leatherback sea turtles, Dermochelys coriacea , undertake broad oceanic movements. While satellite telemetry has been used to investigate the post-nesting behaviour of female turtles tagged on tropical nesting beaches, long-term behavioural patterns of turtles of different sexes and sizes have not been described. Here we investigate behaviour for 25 subadult and adult male and female turtles satellite-tagged in temperate waters off Nova Scotia, Canada. Although sex and reproductive condition contributed to variation in migratory patterns, the migratory cycle of all turtles included movement between temperate and tropical waters. Marked changes in rates of travel, and diving and surfacing behaviour, accompanied southward movement away from northern foraging areas. As turtles approached higher latitudes the following spring and summer, they assumed behaviours consistent with regular foraging activity and eventually settled in coastal areas off Canada and the northeastern USA. Behavioural patterns corresponding to various phases of the migratory cycle were consistent across multiple animals and were repeated within individuals that completed return movements to northern waters. We consider the potential biological significance of these patterns, including how turtle behaviour relates to predator avoidance, thermoregulation and prey distribution.


1992 ◽  
Vol 4 (1) ◽  
pp. 31-36 ◽  
Author(s):  
P. A. Prince ◽  
A. G. Wood ◽  
T. Barton ◽  
J. P. Croxall

The movements of two wandering albatrosses, one of each sex, breeding at South Georgia, were tracked using satellite telemetry, particularly to assess whether such birds could be at risk from longline fishing operations in the subtropics. Full details of the performance (number and quality of uplinks) of the Toyocom transmitters are provided, together with data on flight speeds and night and daytime travel by the albatrosses. The female, tracked for seventeen days—covering three foraging trips totalling 13951 km - had a much more northerly distribution than the male, which made two trips to sea during the same period and travelled a minimum distance of 9280 km. On one trip the female frequented the area off Brazil known to be used for longline fisheries. The distributional differences between the sexes support earlier suggestions, based on at-sea observations, that the observed high mortality rates of South Georgian females could be due to a greater likelihood of incidental mortality in longline fishing. These results also show that the presence of females off Brazil can include birds still rearing chicks, rather than simply representing post-breeding dispersal.


2012 ◽  
Vol 461 ◽  
pp. 223-232 ◽  
Author(s):  
LA Hawkes ◽  
J Tomás ◽  
O Revuelta ◽  
YM León ◽  
JM Blumenthal ◽  
...  

2021 ◽  
Author(s):  
Michelle Modest ◽  
Ladd Irvine ◽  
Virginia Andrews-Goff ◽  
William Gough ◽  
David Johnston ◽  
...  

Abstract Background: Despite exhibiting one of the longest migrations in the world, half of the humpback whale migratory cycle has remained unexamined; until this point, no study has provided a continuous description of humpback whale migratory behavior from a feeding ground to a breeding ground. We present new information on the satellite derived offshore migratory movements of 16 humpback whales from Antarctic feeding grounds to South American breeding grounds. Satellite locations were used to demonstrate migratory corridors, while the impact of departure date on migration speed was assessed using a linear regression, and a Bayesian hierarchical state-space animal movement model was utilized to investigate the presence of feeding behavior en route. Results: 35,642 Argos locations from 16 tagged whales from 2012-2017 were collected. The 16 whales were tracked for an average of 38.5 days of migration (range 10-151 days). The length of individually derived tracks ranged from 645–6,381 km. Humpbacks were widely dispersed geographically during the initial and middle stages of their migration but convened in two bottleneck regions near the southernmost point of Chile as well as Peru’s Illescas Peninsula. The state space model found almost no instances of ARS, a proxy for feeding behavior, along the migratory route. The linear regression assessing whether departure date affected migration speed found suggestive but inconclusive support for a positive trend between the two variables. No clear stratification by sex or reproductive status, either in migration speed, departure date, or route choice, was found.Conclusions: Southern hemisphere humpback whale populations are recovering quickly from intense commercial whaling and, around the Antarctic Peninsula, are doing so in the face of a rapidly changing environment. The current lack of scientific knowledge on marine mammal migration is a major barrier to cetacean conservation. This multi-year study sets a baseline against which the effects of climate change on humpback whales can be studied across years and conditions and provides an excellent starting point for the investigation into humpback whale migration.


2021 ◽  
Vol 12 ◽  
Author(s):  
Stanca M. Ciupe ◽  
Brittany P. Boribong ◽  
Sarah Kadelka ◽  
Caroline N. Jones

The highly controlled migration of neutrophils toward the site of an infection can be altered when they are trained with lipopolysaccharides (LPS), with high dose LPS enhancing neutrophil migratory pattern toward the bacterial derived source signal and super-low dose LPS inducing either migration toward an intermediary signal or dysregulation and oscillatory movement. Empirical studies that use microfluidic chemotaxis-chip devices with two opposing chemoattractants showed differential neutrophil migration after challenge with different LPS doses. The epigenetic alterations responsible for changes in neutrophil migratory behavior are unknown. We developed two mathematical models that evaluate the mechanistic interactions responsible for neutrophil migratory decision-making when exposed to competing chemoattractants and challenged with LPS. The first model, which considers the interactions between the receptor densities of two competing chemoattractants, their kinases, and LPS, displayed bistability between high and low ratios of primary to intermediary chemoattractant receptor densities. In particular, at equilibrium, we observe equal receptor densities for low LPS (< 15ng/mL); and dominance of receptors for the primary chemoattractant for high LPS (> 15ng/mL). The second model, which included additional interactions with an extracellular signal-regulated kinase in both phosphorylated and non-phosphorylated forms, has an additional dynamic outcome, oscillatory dynamics for both receptors, as seen in the data. In particular, it found equal receptor densities in the absence of oscillation for super-low and high LPS challenge (< 0.4 and 1.1 <LPS< 375 ng/mL); equal receptor densities with oscillatory receptor dynamics for super-low LPS (0.5 < LPS< 1.1ng/mL); and dominance of receptors for the primary chemoattractant for super-high LPS (>376 ng/mL). Predicting the mechanisms and the type of external LPS challenge responsible for neutrophils migration toward pro-inflammatory chemoattractants, migration toward pro-tolerant chemoattractants, or oscillatory movement is necessary knowledge in designing interventions against immune diseases, such as sepsis.


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