1,379 research outputs found
Reisinger Jenő könyve
No full texthttp://www.lib.unideb.huDebreceni Egyetem Egyetemi és Nemzeti Könyvtár"Reisinger Jenő könyve" felirat R kezdőbetűjén karikaturisztikus holló-figura, amint csőrével éppen az előtte levő nyitott kódexből próbálja kitépni az ex librist. A holló lábánál készítői névjel.metszetPetr
Reisinger Jenő ex librise
No full textVadászhttp://www.lib.unideb.huDebreceni Egyetem Egyetemi és Nemzeti KönyvtárSapkás férfi oldalnézetből, "R" és "J" betűkön áll. Jobbra kis méretű képek, ezekből egyet a figura a bal kezében tart. Körben felirat: Ex libris Reisinger Jenő. Jobbra készítő névjele.metsze
Population size estimate of Indo-Pacific bottlenose dolphins in the Algoa Bay region, South Africa
No full textThis study estimates the population size of Indo-Pacific bottlenose dolphins (Tursiops aduncus) in the Algoa Bay region on the Eastern Cape coast of South Africa. Mark-recapture analyses were performed on photo-identification data collected on 54 occasions during a 3-yr-study period. Using a photographic data set of over 10,000 ID-images, 1,569 individuals were identified, 131 of which were photographed on more than one occasion. Using the POPAN formulation in the software program MARK, a total population of approximately 28,482 individuals (95% CI = 16,220-40,744; CV = 0.220), was estimated (estimate corrected for the proportion of distinctive individuals in the population). This is the largest population estimate to date for this species along the South African coast, suggesting that the bottlenose dolphins inhabiting the Algoa Bay region represent part of a substantially larger population that ranges along a considerable length of the South African coast. © 2009 by the Society for Marine Mammalogy.link_to_subscribed_fulltex
Vagrant Antarctic fur seals at Gough Island in 2009
No full textThe Antarctic fur seal Arctocephalus gazella at
Gough Island (40°20 S, 09°54 W) in the South Atlantic Ocean, first seen in October/November 2005, was recorded again in September–October 2009. Up to three different individual Antarctic fur seals were sighted on a single day, on a particular beach. A total of seven different individuals were recorded over a 3-week period, well before the onset of the breeding (pupping) season of the resident population of Subantarctic fur seals A. tropicalis. Positively identified
individuals were all male, mostly subadult and lean. Only a fraction (»20%) of the available beaches was searched, and it is unknown if the Antarctic fur seals were still present at Gough Island during the austral summer breeding season of southern fur seals
Goose barnacles on seals and a penguin at Gough Island
No full textDuring a survey of seals in September and October
2009 at Gough Island, South Atlantic Ocean, we
recorded goose barnacles (Lepas australis) attached to the pelage of two of the 12 elephant seals (Mirounga leonina) inspected and one of the seven vagrant Antarctic fur seals (Arctocephalus gazella) which were found amongst the resident Subantarctic fur seals (A. tropicalis). We also recorded a goose barnacle attached to a Northern rockhopper penguin (Eudyptes chrysocome moseleyi)
Long distance breeding dispersal of a southern elephant seal
No full textSouthern elephant seals range extensively during regular foraging excursions. Despite this they are highly
philopatric and long range dispersal is rare. At Gough Island, southern Atlantic Ocean, we observed a breeding
adult male elephant seal during September 2009 which had been tagged on its natal beach at Marion Island,
southern Indian Ocean, in November 1998. The individual was resighted only once on Marion Island – six
months after tagging. This 3,860 km movement represents dispersal (and likely gene flow) between distinct
populations from different elephant seal geographical provinces. Given the polygynous breeding system of this
species, the presence of this single male may have a disproportionate genetic effect on the small number of
southern elephant seals breeding at Gough Island
Predatory impact of killer whales on pinniped and penguin populations at the Subantarctic Prince Edward Islands : fact and fiction
No full textKiller whales are the oceans’ apex predators and their potential effects on ecosystems have been
demonstrated. In the Southern Ocean the role of killer whale predation in population declines of southern
elephant seals remains largely speculative. We aimed to assess whether top-down control of pinniped and
penguin populations at the Subantarctic Prince Edward Islands is generally plausible using a simple process of
elimination. Based on published data we predicted the energetic ingestion requirements of adult male and
female killer whales as 1 394 MJ.day-1 and 1 028 MJ.day-1, respectively. Expanding these requirements to the
37 killer whales photographically identified at the Prince Edward Islands, the population requires
40 600MJ.day-1. Based on available energy density and mass data, we predicted the energy content of
available pinniped and penguin prey and calculated the rates at which killer whales would consume these prey
in various scenarios. Penguins and Subantarctic fur seals are relatively insensitive to killer whale predation
owing to their large population sizes (10 000s – 100 000s). Conversely, the smaller populations (100s – 1 000s)
of Antarctic fur seals and southern elephant seals are sensitive to predation, particularly the latter as they have
a high energy content (ca. 2 000 – 9 000 MJ). Populations of these seals are currently increasing or stable and
we conclude that presently killer whale predation is not driving population declines, although they clearly have
the potential for regulation of these smaller populations. Thus, if population sizes were reduced by bottom-up
processes, if killer whale diet shifted, or if prey availability changed, top-down predation by killer whales could become significant. By eliminating the possibility of some predation scenarios, we are better able to
concentrate future efforts on plausible predation effects.Department of Science and Technology (administered
through the National Research Foundation) for funding the marine
mammal monitoring programme at Marion Island.http://www3.interscience.wiley.com/journal/118535410/home-8369nf201
Editorial: tracking marine megafauna for conservation and marine spatial planning
No full textDespite their important role in ecosystems, the widespread and increasing threats faced by many marine megafauna taxa has led to a poor conservation status of many species (e.g., Rees et al., 2016; Dias et al., 2019; Nelms et al., 2021; Jorgensen et al., 2022). Understanding and mitigating the threats faced by marine megafauna is challenging (Lascelles et al., 2014; Reisinger et al., 2022) because both the threats and the marine environment are highly dynamic in space and time, and animals’ occurrences vary with shifts in environmental and oceanographic conditions at different scales. Additionally, these animals are often highly mobile, making it difficult to pinpoint the occurrences of different individuals in specific locations.There are several definitions for the term ‘marine megafauna’. For example, Estes et al. (2016) define marine megafauna as species with maximum reported mass >45 kg, including 338 extant species of cetaceans, pinnipeds, sirenians, the sea otter (Enhyrda lutris), the polar bear (Ursus maritimus), the emperor penguin (Aptenodytes forsteri), marine reptiles, bony and cartilaginous fishes, cephalopods, and the giant clam (Tridacna gigas). Here, we take the view of Authier et al. (2017), who do not impose a strict body mass threshold, but consider marine megafauna to be a coherent group based on their ecological similarities (at or near the top of food webs, with no or few predators) and that share conservation issues.This Research Topic covers a broad taxonomic representation, spanning seabirds, cetaceans, sea turtles, pinnipeds, elasmobranchs, teleosts, a sirenian, the polar bear, and a large crustacean, the red king crab (Paralithodes camtschaticus). Articles submitted address how biologging is being used to understand the movement behaviour and distribution of marine megafauna, and how this information can play a key role to prioritise conservation goals. The resulting 34 articles illustrate how biologging is informing conservation of marine megafauna, and in light of these studies, we discuss challenges, methodological implications and future directions for biologging in conservation
Goose barnacles hitchhike on satellite-tracked southern elephant seals
No full textGoose barnacles (Lepas australis) attached to
satellite-relay data loggers were carried by three southern elephant seals (Mirounga leonina) from Marion Island. Their movements across the Polar Frontal Zone are presented, providing further evidence that megafauna are potential vectors for the transport of species into the Southern Ocean
Killer whale predation on subantarctic fur seals at Prince Edward Island, Southern Indian Ocean
No full textKiller whales at subantarctic Marion Island have been subjected to several scientific studies. In contrast, up until recently, there has been only one record of these animals documented for neighbouring Prince Edward Island. We here report on killer whale observations at Prince Edward Island during March 2012. During 3 days of opportunistic observations at a fur seal colony on the island, killer whales were sighted on six occasions. These probably represented three different pods numbering 11 individuals in total. During all sightings, individuals were seen hunting subantarctic fur seal pups, with four successful predatory events observed.</p
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