Yves Handrich

Bio: Yves Handrich is an academic researcher from University of Strasbourg. The author has contributed to research in topics: Foraging & Aptenodytes patagonicus. The author has an hindex of 36, co-authored 120 publications receiving 3793 citations. Previous affiliations of Yves Handrich include National Institute of Polar Research & Centre national de la recherche scientifique.

Buoyancy and maximal diving depth in penguins: do they control inhaling air volume?

Abstract: Using a newly developed data logger to measure acceleration, we demonstrate that free-ranging king and Adelie penguins only beat their flippers substantially during the first part of descent or when they were presumed to be chasing prey at the bottom of dives. Flipper beating stopped during the latter part of ascent: at 29±9 % (mean ± S.D.) of dive depth (mean dive depth=136.8±145.1 m, N =425 dives) in king penguins, and at 52±20 % of dive depth (mean dive depth=72.9±70.5 m, N =664 dives) in Adelie penguins. Propulsive swim speeds of both species were approximately 2 m s-1 during dives; however, a marked increase in speed, up to approximately 2.9 m s-1, sometimes occurred in king penguins during the passive ascending periods. During the prolonged ascending, oblique ascent angle and slowdown near the surface may represent one way to avoid the potential risk of decompression sickness. Biomechanical calculations for data from free-ranging king and Adelie penguins indicate that the air volume of the birds (respiratory system and plumage) can provide enough buoyancy for the passive ascent. When comparing the passive ascents for shallow and deep dives, there is a positive correlation between air volume and the depth of the dive. This suggests that penguins regulate their air volume to optimize the costs and benefits of buoyancy.

Stroke frequency, but not swimming speed, is related to body size in free-ranging seabirds, pinnipeds and cetaceans

Abstract: It is obvious, at least qualitatively, that small animals move their locomotory apparatus faster than large animals: small insects move their wings invisibly fast, while large birds flap their wings slowly. However, quantitative observations have been difficult to obtain from free-ranging swimming animals. We surveyed the swimming behaviour of animals ranging from 0.5 kg seabirds to 30 000 kg sperm whales using animal-borne accelerometers. Dominant stroke cycle frequencies of swimming specialist seabirds and marine mammals were proportional to mass(-0.29) (R(2)= 0.99, n = 17 groups), while propulsive swimming speeds of 1-2 m s(-1) were independent of body size. This scaling relationship, obtained from breath-hold divers expected to swim optimally to conserve oxygen, does not agree with recent theoretical predictions for optimal swimming. Seabirds that use their wings for both swimming and flying stroked at a lower frequency than other swimming specialists of the same size, suggesting a morphological trade-off with wing size and stroke frequency representing a compromise. In contrast, foot-propelled diving birds such as shags had similar stroke frequencies as other swimming specialists. These results suggest that muscle characteristics may constrain swimming during cruising travel, with convergence among diving specialists in the proportions and contraction rates of propulsive muscles.

Foraging habitat and food intake of satellite-tracked king penguins during the austral summer at Crozet Archipelago

Abstract: The relationsh~ps between the foraging strategy of seabirds, hydrographic features and food availability are poorly understood. We investigated the movements at sea, time spent per oceanic sector, food intake, and d ~ e t of king pengulns Aptenodytespatagonicus in the Crozet Islands (Southern Indian Ocean) during summer, as a function of the position of major frontal zones. Fifteen trips at sea were monitored using satelhte transmitters over 3 austral summers (1992 to 1994). During each season, satellite transmitters were used in conjunction with stomach temperature recorders in order to investigate feeding activity. The at-sea distribution of klng penguins was closely related to the localisation of major hydrographic frontal systems. Intense prospecting areas were observed mainly in zones corresponding to the northern h i t of the Polar Front (50\" to 51°S), southern limit of the Sub-Antarctic Front (44.50' to 45O S], and a zone between 47' and 48\" S. During trips directed south, 2 distinct phases based on travelling speed were detected. The myctophids Electrons carlsbergi, Krefftichtys anderssoni and Protomyctophurn tenisoni dominated the diet. The est~mated average amount of food ingested per day at sea was 2.4 kg. Between 17 and 64 kg of food was captured during 7 to 25 d at sea. Approximately 80% of the food intake occurred during the first phase of the trip. Food intake was related to trip duration and relative amount of time spent in particular oceanic sectors. The sections 47' to 48\" S and 48.5\" to 50.50\" S appeared particularly favorable for food intake, the latter coinciding with the northern limit of the Polar Front. King penguins fed ~ntensively on several distinct patches when traveling towards the Polar Front. The foraging range seems to be related to the foraging success during the first phase of the trip. The foraging strategy of king penguins during the summer favors displacements toward frontal zones where food availability is optimal.

Hypothermia in foraging king penguins

Abstract: The ability to dive for long periods increases with body size1, but relative to the best human divers, marine birds and mammals of similar or even smaller size are outstanding performers. Most trained human divers can reach a little over 100 m in a single-breath dive lasting for 4 min (ref. 2), but king and emperor penguins (weighing about 12 and 30 kg, respectively) can dive to depths of 304 and 534 m for as long as 7.5 and 15.8 min, respectively3,4,5. On the basis of their assumed metabolic rates, up to half of the dive durations were believed to exceed the aerobic dive limit, which is the time of submergence before all the oxygen stored in the body has been used up4,6,7. But in penguins and many diving mammals7,8, the short surface intervals between dives are not consistent with the recovery times associated with a switch to anaerobic metabolism4. We show here that the abdominal temperature of king penguins may fall to as low as 11 °C during sustained deep diving. As these temperatures may be 10 to 20 °C below stomach temperature, cold ingested food cannot be the only cause of abdominal cooling. Thus, the slower metabolism of cooler tissues resulting from physiological adjustments associated with diving per se, could at least partly explain why penguins and possibly marine mammals can dive for such long durations.

Stress in birds due to routine handling and a technique to avoid it

Abstract: The stress that might result in animals from the routine handling that most experimental studies involve, e.g., weighing, injecting, and blood sampling, is usually assumed to be minimal when the animals look quiet. However, the intensity of this stress remains largely ignored. We have developed a system that allows blood samples to be taken from freely behaving geese without entering the animal room. In these entirely undisturbed geese, the humoral indexes of stress, i.e., blood levels of catecholamines, corticosterone, and lactate, were as low or even lower than the lowest values previously reported for birds. Remarkably, the mean basal values for epinephrine and norepinephrine were 90-fold and 5-fold, respectively, below the lowest values in the literature. Stress-induced variations in pH that would have concealed detection of nutrition-induced changes in pH were eliminated. In contrast, even though the birds looked quiet during a short 5-min routine handling procedure, to which they had been accustomed for weeks, there was a dramatic increase in the level of humoral indexes of stress. These increased severalfold within only 2 min, and the return to initial values could take up to 1 h. Acid-base balance was also disrupted. Thus, in studies on animals, the absence of stress cannot be deduced from only behavioral observations. Only a system for taking blood without human interference may enable stress-free investigations.

Modern Applied Statistics With S

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Applied Linear Regression Models

Abstract: (1991). Applied Linear Regression Models. Journal of Quality Technology: Vol. 23, No. 1, pp. 76-77.

Stress and Decision Making under the Risk of Predation: Recent Developments from Behavioral, Reproductive, and Ecological Perspectives

Abstract: Publisher Summary This chapter reviews the present empirical and theoretical work on antipredator decision making. The ways in which predators influence the behavioral decisions made by their prey is now the subject of a large and growing literature. Some notable recent advances include clear demonstrations that antipredatory decision making (1) may influence many aspects of reproductive behavior, (2) has demonstrable long-term consequences for individual fitness, and (3) may influence the nature of ecological systems themselves. There have also been many advances in the theory of antipredator behavior, which should provide a sound conceptual basis for further progress. Attention is needed for further work on the effects that predator and prey have on the other's behavioral decisions. The range of reproductive behaviors influenced by the risk of predation also requires much more investigation. Work on the long-term costs of antipredator decision making needs more empirical documentation and greater taxonomic diversity. Work on the ecological implications of antipredatory decision making has only scratched the surface, especially with regard to population-level effects and species interactions. Theoretical investigations should also play a prominent role in future work.