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Kenneth L. Campbell - One of the best experts on this subject based on the ideXlab platform.

Skorić Stefan - One of the best experts on this subject based on the ideXlab platform.

  • Allocation of Metals and Trace Elements in Different Tissues of Piscivorous Species Phalacrocorax Carbo
    Archives of Environmental Contamination and Toxicology, 2017
    Co-Authors: Hribšek Irena, Jovičić Katarina, Karadžić Branko, Skorić Stefan
    Abstract:

    Great cormorants ( Phalacrocorax Carbo ) are piscivorous birds, and as apex predators they accumulate high levels of contaminants from the aquatic ecosystems. In the present study, we analyzed distribution of Al, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sr, and Zn in ten tissues (muscle, liver, kidney, spleen, gizzard, heart, skin, lard, breast feathers, and remiges) of the Great cormorants in the Marin Sprud locality, the Danube River, Serbia. Concentrations of elements in tissues were assessed by using inductively coupled plasma optical spectrometry. Linear discriminant analysis indicates that breast feathers and remiges have a high bioaccumulation potential for heavy metals (Cr, Pb, Sr, and Zn). Those tissues had the highest concentrations of lead (Pb) (2.179 ± 0.742; 0628 ± 0.282). Maximum concentrations of mercury (Hg) were detected in liver (30.673 ± 14.081), followed by kidney, for the same element (17.409 ± 5.676), respectively. The overall maximum metal accumulation was observed in breast feathers and remiges, followed by liver and kidney, whereas the minimum values were observed in muscle, skin, and lard. The greatest concentrations of Cr, Ni, Pb, Sr, Zn, and Al were detected in feather tissues. Our study confirms that great cormorant is a good indicator species for monitoring of pollution of river and wetland ecosystems.

  • Allocation of Metals and Trace Elements in Different Tissues of Piscivorous Species Phalacrocorax Carbo
    2017
    Co-Authors: Hribšek Irena, Jovičić Katarina, Karadžić Branko, Skorić Stefan
    Abstract:

    Great cormorants (Phalacrocorax Carbo) are piscivorous birds, and as apex predators they accumulate high levels of contaminants from the aquatic ecosystems. In the present study, we analyzed distribution of Al, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sr, and Zn in ten tissues (muscle, liver, kidney, spleen, gizzard, heart, skin, lard, breast feathers, and remiges) of the Great cormorants in the Marin Sprud locality, the Danube River, Serbia. Concentrations of elements in tissues were assessed by using inductively coupled plasma optical spectrometry. Linear discriminant analysis indicates that breast feathers and remiges have a high bioaccumulation potential for heavy metals (Cr, Pb, Sr, and Zn). Those tissues had the highest concentrations of lead (Pb) (2.179 ± 0.742; 0628 ± 0.282). Maximum concentrations of mercury (Hg) were detected in liver (30.673 ± 14.081), followed by kidney, for the same element (17.409 ± 5.676), respectively. The overall maximum metal accumulation was observed in breast feathers and remiges, followed by liver and kidney, whereas the minimum values were observed in muscle, skin, and lard. The greatest concentrations of Cr, Ni, Pb, Sr, Zn, and Al were detected in feather tissues. Our study confirms that great cormorant is a good indicator species for monitoring of pollution of river and wetland ecosystems.Archives of Environmental Contamination and Toxicology (2017), 73(4): 533-54

David Grémillet - One of the best experts on this subject based on the ideXlab platform.

  • The relationship between sea surface temperature and population change of Great Cormorants Phalacrocorax Carbo breeding near Disko Bay, Greenland
    Ibis, 2010
    Co-Authors: Craig R. White, David Boertmann, David Grémillet, Patrick J. Butler, Jonathan A. Green, Graham R. Martin
    Abstract:

    Arctic seas have warmed and sea ice has retreated. This has resulted in range contraction and population declines in some species, but it could potentially be a boon for others. Great Cormorants Phalacrocorax Carbo have a partially wettable plumage and seem poorly suited to foraging in Arctic waters. We show that rates of population change of Cormorant colonies around Disko Bay, Greenland, are positively correlated with sea surface temperature, suggesting that they may benefit from a warming Arctic. However, although Cormorant populations may increase in response to Arctic warming, the extent of expansion of their winter range may ultimately be limited by other factors, such as sensory constraints on foraging behaviour during long Arctic nights.

  • Flexible foraging techniques in breeding Cormorants Phalacrocorax Carbo and Shags Phalacrocorax aristotelis : benthic or pelagic feeding?
    Ibis, 2008
    Co-Authors: David Grémillet, G. Argentin, B. Schulte, B. M. Culik
    Abstract:

    A total of 8772 dive durations were recorded during 117 diving bouts in five Cormorants Phalacrocorax Carbo and five Shags Phalacrocorax aristotelis breeding at the Chausey Islands, France. Diet of the birds was assessed by analysis of 526 pellets containing 13,016 otoliths. Radio-tracking data indicated that Cormorants fed exclusively on pelagic fish during social fishing (5% of the trips) and executed 11% pelagic and 60% benthic dives during the remaining 95% of the trips. In Shags, 44% of all trips were pelagic, and the remaining 56% included 9% pelagic and 67% benthic dives. The proportions of benthic to pelagic dives varied widely between dive sequences of single birds and between individuals and sexes in both species. The prey spectrum of the Cormorants contained both pelagic (29%) and benthic fish (67%) and confirmed considerable flexibility in foraging. In Shags, birds may adjust their diving patterns to accommodate the behaviour of their main prey, sandeels Ammodytidae (87% of all prey). We propose that the wetability of plumage may explain this flexibility.

  • Unusual feather structure allows partial plumage wettability in diving great cormorants Phalacrocorax Carbo
    Journal of Avian Biology, 2005
    Co-Authors: David Grémillet, Christophe Chauvin, Rory P. Wilson, Yvon Le Maho, Sarah Wanless
    Abstract:

    The great cormorant Phalacrocorax Carbo is thought to have a wettable plumage, providing low body insulation during foraging. Great cormorants should thus be constrained by water temperatures, and show high energy requirements. Surprisingly, this species has one of the widest breeding distributions of all diving birds, and does not require more food than these other species. We explored this apparent paradox by comparing the insulative properties of body plumage in four subspecies of great cormorants ranging from tropical to polar regions. We found that all subspecies retained an insulating air layer in their plumage, which was, however, much thinner than for other species of diving birds. Detailed examination of the plumage showed that each cormorant body feather has a loose, instantaneously wet, outer section and a highly waterproof central portion. This indicates that the plumage of great cormorants is only partly wettable, and that birds maintain a thin layer of air in their plumage. Our findings suggest an unusual morphological-functional adaptation to diving which balances the antagonist constraints of thermoregulation and buoyancy.

  • catch per unit effort foraging efficiency and parental investment in breeding great cormorants Phalacrocorax Carbo Carbo
    Journal of Materials Science, 1997
    Co-Authors: David Grémillet
    Abstract:

    The feeding ecology of breeding great cormorants (Phalacrocorax Carbo Carbo) was studied in 8 males and 6 females using automatic nest-balances and a radio-tracking system. Birds were shown to be extremely efficient predators with median catch per unit effort of 15.2 g of fish taken per minute spent underwater (n=89; gross foraging efficiency 3.25) in males and 9.0 g min −1 in females (n=91; gross foraging efficiency 3.46). Mean daily food intake was also high (828±166 g, n=7 in males and 829±271 g, n=6 in females) and was positively related to brood biomass. Catch per unit effort was not related to foraging range, showing that birds do not tend to visit distant foraging areas to compensate for prey stock depletion around the breeding site. Furthermore, breeding adults responded to increasing food requirements of the brood by increasing the number of foraging trips per day, but maintained constant foraging effort, load size and catch per unit effort. Parents thus increased their overall foraging effort and food intake but kept their body mass constant.

  • Energetics of underwater swimming in the great cormorant (Phalacrocorax Carbo sinensis)
    Marine Biology, 1995
    Co-Authors: D. Schmid, David Grémillet, B. M. Culik
    Abstract:

    Resting metabolic rate (RMR), energy requirements and body core temperature were measured during underwater swimming in great cormorants (Phalacrocorax Carbo sinensis) at the zoological garden in Neumunster, Germany, using gas respirometry and stomach temperature loggers. We used a 13 m long still water canal equipped with a respiration chamber at each end. Birds swam voluntarily in the canal at a mean speed of 1.51 ms-1. Power input during underwater swimming averaged 31.4 W kg-1. Minimal costs of transport of 19.1 J kg-1 m-1 were observed at a speed of 1.92 m s-1. Body core temperature was stable in all birds within the first 60 min spent in the canal. After that, body temperature dropped at a rate of 0.14°C min-1 until the birds voluntarily left the water. Our data indicate that great cormorants spend 2.7 times more energy than Adelie penguins (Pygoscelis adeliae) during underwater swimming. This can be essentially attributed to their poor insulation, their mode of locomotion underwater and differences in streamlining. RMR on land was related to body mass via VO2=0.691 M0.755 (where VO2 is O2-consumption in litre h-1 and M is body mass in kg). In order to quantify the effects of external devices on energy consumption during underwater swimming, we tested a dummy data logger attached to the back of the cormorants as well as a ring on the leg. The ring had no apparent influence on the swimming energetics of the cormorants. In birds equipped with dummy loggers, swimming speed was not significantly influenced, but both power input and costs of transport increased by a mean of 19% for swimming speeds between 1.4 and 1.8 m s-1.

B. M. Culik - One of the best experts on this subject based on the ideXlab platform.

  • Flexible foraging techniques in breeding Cormorants Phalacrocorax Carbo and Shags Phalacrocorax aristotelis : benthic or pelagic feeding?
    Ibis, 2008
    Co-Authors: David Grémillet, G. Argentin, B. Schulte, B. M. Culik
    Abstract:

    A total of 8772 dive durations were recorded during 117 diving bouts in five Cormorants Phalacrocorax Carbo and five Shags Phalacrocorax aristotelis breeding at the Chausey Islands, France. Diet of the birds was assessed by analysis of 526 pellets containing 13,016 otoliths. Radio-tracking data indicated that Cormorants fed exclusively on pelagic fish during social fishing (5% of the trips) and executed 11% pelagic and 60% benthic dives during the remaining 95% of the trips. In Shags, 44% of all trips were pelagic, and the remaining 56% included 9% pelagic and 67% benthic dives. The proportions of benthic to pelagic dives varied widely between dive sequences of single birds and between individuals and sexes in both species. The prey spectrum of the Cormorants contained both pelagic (29%) and benthic fish (67%) and confirmed considerable flexibility in foraging. In Shags, birds may adjust their diving patterns to accommodate the behaviour of their main prey, sandeels Ammodytidae (87% of all prey). We propose that the wetability of plumage may explain this flexibility.

  • Energetics of underwater swimming in the great cormorant (Phalacrocorax Carbo sinensis)
    Marine Biology, 1995
    Co-Authors: D. Schmid, David Grémillet, B. M. Culik
    Abstract:

    Resting metabolic rate (RMR), energy requirements and body core temperature were measured during underwater swimming in great cormorants (Phalacrocorax Carbo sinensis) at the zoological garden in Neumunster, Germany, using gas respirometry and stomach temperature loggers. We used a 13 m long still water canal equipped with a respiration chamber at each end. Birds swam voluntarily in the canal at a mean speed of 1.51 ms-1. Power input during underwater swimming averaged 31.4 W kg-1. Minimal costs of transport of 19.1 J kg-1 m-1 were observed at a speed of 1.92 m s-1. Body core temperature was stable in all birds within the first 60 min spent in the canal. After that, body temperature dropped at a rate of 0.14°C min-1 until the birds voluntarily left the water. Our data indicate that great cormorants spend 2.7 times more energy than Adelie penguins (Pygoscelis adeliae) during underwater swimming. This can be essentially attributed to their poor insulation, their mode of locomotion underwater and differences in streamlining. RMR on land was related to body mass via VO2=0.691 M0.755 (where VO2 is O2-consumption in litre h-1 and M is body mass in kg). In order to quantify the effects of external devices on energy consumption during underwater swimming, we tested a dummy data logger attached to the back of the cormorants as well as a ring on the leg. The ring had no apparent influence on the swimming energetics of the cormorants. In birds equipped with dummy loggers, swimming speed was not significantly influenced, but both power input and costs of transport increased by a mean of 19% for swimming speeds between 1.4 and 1.8 m s-1.

I. J. Linn - One of the best experts on this subject based on the ideXlab platform.