We studied the activities both of digestive enzymes in the small intestine of the herring gull (Larus argentatus) and a tapeworm Diphyllobothrium dendriticum (Cestoda: Diphyllobothriidae) residing in the intestine. It was found that D. dendriticum infects the medial section of the small intestine of the herring gull. Such localization of D. dendriticum is caused by the maximal activity of proteases and glycosidases and by the high rate of membrane and cavitary digestion in this section. The activity of protease and glycosidase in gulls infected with D. dendriticum is decreased. The activity of proteases in the fractions desorbed from the tegument surface of D. dendriticum is significantly higher than that of glycosidases.
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J Anim Ecol
January 2025
Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada.
Pulsed resources resulting from animal migrations represent important, transient influxes of high resource availability into recipient communities. The ability of predators to respond and exploit these large increases in background resource availability, however, may be constrained when the timing and magnitude of the resource pulse vary across years. In coastal Newfoundland, Canada, we studied aggregative responses of multiple seabird predators to the annual inshore pulse of a key forage fish species, capelin (Mallotus villosus).
View Article and Find Full Text PDFSci Rep
November 2024
Department of Behavioural Ecology, University of Wrocław, Sienkiewicza 21, 50-335, Wrocław, Poland.
Hybridization is a common phenomenon in birds, particularly between closely related species, when reproductive isolation mechanisms are insufficiently developed. Hybrids differ from the parental species in genetic, morphological, and behavioural traits. However, the migration patterns of hybrids have been scarcely studied.
View Article and Find Full Text PDFChemosphere
November 2024
Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Directorate, Science and Technology Branch, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Ottawa, ON, Canada; Department of Chemistry, Carleton University, Ottawa, ON, K1S 5B6, Canada. Electronic address:
Methoxylated polybrominated diphenoxybenzenes (MeO-PB-DPBs) are little known contaminants except in North American Great Lakes herring gull tissues and egg samples. MeO-PB-DPBs in gulls originate not via aquatic bioaccumulation pathways but instead likely via transformation of the tetradecabromo-1,4-diphenoxybenzene (TDB-DPB) flame retardant (FR). TDB-DPB was formerly produced as SAYTEX-120 in North America and is still produced in Asia.
View Article and Find Full Text PDFSci Total Environ
November 2024
Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS - La Rochelle Université, 17000 La Rochelle, France.
Mercury (Hg) is a naturally occurring highly toxic element which circulation in ecosystems has been intensified by human activities. Hg is widely distributed, and marine environments act as its main final sink. Seabirds are relevant bioindicators of marine pollution and chicks are particularly suitable for biomonitoring pollutants as they reflect contamination at short spatiotemporal scales.
View Article and Find Full Text PDFJ Hazard Mater
September 2024
Environment and Climate Change Canada, National Wildlife Research Centre, 1125 Colonel By Drive, Ottawa, K1A 0H3 Ontario, Canada.
The objectives of this research were to assess ingested plastics and accumulated heavy metals in four urban gull species. Additionally, the relationships between ingested plastics and selected demographic and health metrics were assessed. Between 2020-2021 during the non-breeding seasons, 105 gulls (46 American herring gulls (HERG, Larus argentatus smithsonianus), 39 great black-backed gulls (GBBG, Larus marinus), 16 Iceland gulls (Larus glaucoides), 4 glaucous gulls (Larus hyperboreus)) were killed at a landfill in coastal Newfoundland and Labrador, Canada, as part of separate, permitted kill-to-scare operations related to aircraft safety.
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