Acanthocephalan infection of inshore fish in two fjords at South Georgia

1992 ◽  
Vol 4 (2) ◽  
pp. 197-203 ◽  
Author(s):  
Krzysztof Zdzitowiecki ◽  
Martin G. White
Keyword(s):  
Dominant Species ◽  
Alimentary Tract ◽  
Body Cavity ◽  
The Body ◽  
South Shetland Islands ◽  
Shetland Islands ◽  
South Georgia ◽  
Species Association ◽  
Fur Seal ◽  
Seal Population

An examination of 111 fish of eight species, including 92 immature Notothenia rossii Richardson revealed nine acanthocephalan species, including four Echinorhynchida occurring in the alimentary tract and five Polymorphida in the body cavity. Echinorhynchida were much more numerous (87% specimens of 4855 collected), especially Metacanthocephalus johnstoni Zdzitowiecki (the dominant species) and Aspersentis megarhynchus (Linstow). The Polymorphida parasites of seals (three species) were more abundant than species parasitic in birds (two species). Association of most of species, (except Corynosoma bullosum (Linstow) and Echinorhynchus spp.), with the inshore (fjord) environment was confirmed. The species diversity, prevalence and density of infection increased with the size of immature N. rossii. Differences in acanthocephalan occurrence and changes with time are related to differences in host distribution and abundance. For example, the occurrence of C. arctocephali in N. rossii at South Georgia is related to the increase of the fur seal population. A list of acanthocephalans in fish at South Georgia and the South Shetland Islands (14 species in total) is included.

Acanthocephalan infection of inshore fishes at the South Orkney Islands

1996 ◽  
Vol 8 (3) ◽  
pp. 273-276 ◽  
Author(s):  
Krzysztof Zdzitowiecki ◽  
Martin G. White
Keyword(s):  
Body Cavity ◽  
The Body ◽  
South Shetland Islands ◽  
The South ◽  
Shetland Islands ◽  
Orkney Islands ◽  
Notothenia Coriiceps ◽  
South Orkney Islands ◽  
Chaenocephalus Aceratus ◽  
First Time

An examination of notothenioid fish of three species, including 23 immature Notothenia coriiceps Richardson, revealed seven acanthocephalan species, including two Echinorhynchida occurring in the intestine and five Polymorphida in the body cavity. Four species -Metacanthocephalus johnstoni Zdzitowiecki, Corynosoma arctocephali Zdzitowiecki, C. pseudohamanni Zdzitowiecki, C.shackletoni Zdzitowiecki - are reported for the first time from the area. Polymorphida were twice as numerous as Echinorhynchida. The dominant parasites were Aspersentis megarhynchus (Linstow) and C. hamanni (Linstow) in Notothenia coriiceps, and C. bullosum (Linstow) in Chaenocephalus aceratus (Lönnberg). The infection of Notothenia coriiceps and Chaenocephalus aceratus in this area was compared with these species and Notothenia rossii Richardson in neighbouring areas. The infection of Notothenia coriiceps at the South Orkney Islands is more similar to that at the South Shetland Islands than that found at South Georgia.

Growth of a fur seal population

1977 ◽  
Vol 279 (963) ◽  
pp. 67-79 ◽  
Keyword(s):  
Age Groups ◽  
Population Increase ◽  
South Shetland Islands ◽  
First Year ◽  
South Georgia ◽  
Fur Seals ◽  
Fur Seal ◽  
Younger Age ◽  
Seal Population ◽  
Incipient Colonies

The Antarctic fur seal Arctocephalus gazella is a polygynous Otarid in which a single pup is produced annually by cows over the age of 2 years. Following exploitation to the verge of extinction, a small breeding colony was discovered at Bird Island, South Georgia, in the 1930s. Up to 10000 pups a year were produced in the early 1960s and by 1975 the figure had reached an estimated 90000. The rapid population increase has resulted in the colonization of extensive breeding areas on the adjacent mainland of South Georgia with incipient colonies springing up on more distant parts of the island, and also in the South Sandwich, South Orkney and South Shetland Islands. Age determinations from the teeth of 195 breeding cows reveal a low mean age, early first breeding and a predominance of the younger age groups relative to the age structure of a stable population of northern fur seals Callorhinus ursinus . Annual adult cow survival is estimated at 89.8%, while that of first-year animals is about 64.5%. A decline in the rate of population increase is forecast within ten years and an outline for investigating the most likely factors influencing such a change is suggested.

Conserving the oldest historic sites in the Antarctic: the challenges in managing the sealing sites in the South Shetland Islands

Polar Record ◽  
2009 ◽  
Vol 46 (1) ◽  
pp. 57-64 ◽  
Author(s):  
Michael Pearson ◽  
Ruben Stehberg ◽  
Andrés Zarankín ◽  
M. Ximena Senatore ◽  
Carolina Gatica
Keyword(s):  
South Shetland Islands ◽  
The South ◽  
Shetland Islands ◽  
Fur Seals ◽  
Fur Seal ◽  
Seal Population ◽  
Animal Activity ◽  
South Shetlands ◽  
The Antarctic ◽  
Management Issues

ABSTRACTThe fur seal population of the South Shetland Islands, Antarctica, was intensively hunted by sealers from the discovery of the islands in 1819 to the early 1820s, by which time the seal numbers were so depleted that sealing became uneconomic. Sealing was revived for both fur seals and elephant seals at several periods later in the century. Sealers were put ashore in gangs and built makeshift shelters in which to live, and also occupied caves. Many of these have been identified on the various islands of the South Shetlands, and a number have been excavated. The paper addresses some of the management issues facing the conservation of these sites, which include accelerating tourism, disturbance by scientific researchers, disturbance by animal activity, burial or erosion by drifting sand, and climate change.

Digenean Trematoda infection of inshore fish at South Georgia

1992 ◽  
Vol 4 (1) ◽  
pp. 51-55 ◽  
Author(s):  
Krzysztof Zdzitowiecki ◽  
Martin G. White
Keyword(s):  
Dominant Species ◽  
Common Species ◽  
South Shetland Islands ◽  
Admiralty Bay ◽  
Shetland Islands ◽  
South Georgia ◽  
Digenean Species ◽  
Digenean Trematode ◽  
Notothenia Rossii ◽  
Trematode Parasites

A sample of 111 fish of eight species caught in two fjords at South Georgia were examined for digenean trematode parasites. The alimentary tracts of all specimens were infected with digeneans. The dominant species was Elytrophalloides oatesi (Leiper & Atkinson) which was found in all fish, with a maximum number of 1961 specimens per fish. Other common species were; Macvicaria pennelli (Leiper & Atkinson), Lepidapedon garrardi (Leiper & Atkinson), Lecithaster macrocotyle Szidat & Graefe, Genolinea bowersi (Leiper & Atkinson) and Postmonorchis variabilis Prudhoe & Bray. Three further species, Neolebouria antarctica (Szidat & Graefe), Discoverytrema markowskii Gibson and Gonocerca phycidis Manter, were rare. Infection of the most commonly caught fish at South Georgia, Notothenia rossii Richardson, is compared with that of N. rossii at Admiralty Bay, South Shetland Islands. The species composition of common parasites was similar in both areas but conspicuous differences in the frequency of individual digenean species were found.

Colony growth and pup condition of the New Zealand fur seal (Arctocephalus forsteri) on the Kaikoura coastline compared with other east coast colonies

2006 ◽  
Vol 33 (6) ◽  
pp. 497 ◽  
Author(s):  
L. J. Boren ◽  
C. G. Muller ◽  
N. J. Gemmell
Keyword(s):  
New Zealand ◽  
Body Condition ◽  
East Coast ◽  
Colony Growth ◽  
The Body ◽  
Fur Seal ◽  
Seal Population ◽  
Condition Indices ◽  
New Zealand Fur Seal ◽  
Breeding Seasons

Abstract.Since its near extermination by sealing, the New Zealand fur seal (Arctocephalus forsteri) has been recolonising areas of its former range throughout New Zealand and Australia. This study examined fur seal population growth over four breeding seasons spanning 2002–05 at the Ohau Point and Lynch’s Reef colonies in Kaikoura and the Horseshoe Bay and Te Oka Bay colonies on Banks Peninsula, on the east coast of New Zealand. Estimates of pup numbers were made using mark–recapture techniques and condition indices were used to assess the body condition of pups in each colony. We found that the Ohau Point and Te Oka Bay colonies are growing exponentially (32% and 47% per annum respectively), reaching nearly 600 pups at Ohau Point and 300 pups at Te Oka Bay, whereas Horseshoe Bay appears stable. Pups born at Ohau Point are consistently heavier and in better condition than their Banks Peninsula counterparts despite the faster rate of growth observed at Te Oka Bay. An El Niño event in 2003 coincided with a drop in mass and condition at the Banks Peninsula colonies, but not at the Kaikoura colony. This discrepancy between colonies in response to environmental conditions suggests that colony-specific variables at Kaikoura may provide more favourable conditions for rearing pups than on Banks Peninsula.

scholarly journals Records of Parochlus steinenii in the Maritime Antarctic and sub-Antarctic regions

ZooKeys ◽  
2021 ◽  
Vol 1011 ◽  
pp. 63-71
Author(s):  
Melisa Gañan ◽  
Tamara Contador ◽  
Javier Rendoll ◽  
Felipe Simoes ◽  
Carolina Pérez ◽  
...  
Keyword(s):  
Biosphere Reserve ◽  
South Shetland Islands ◽  
Maritime Antarctic ◽  
The South ◽  
Global Biodiversity Information Facility ◽  
Shetland Islands ◽  
South Georgia ◽  
Darwin Core ◽  
Complete Dataset ◽  
Antarctic Continent

This study provides the summary of the reports of the geographical distribution in the Maritime Antarctic and sub-Antarctic regions of Parochlus steinenii (Gercke, 1889) (Diptera, Chironomidae), the only flying insect occurring naturally in the Antarctic continent. The distribution encompasses the South Shetland Islands (Maritime Antarctic), South Georgia (sub-Antarctic), and parts of the Cape Horn Biosphere Reserve (CHBR, southern Chile). In total 78 occurrence records were identified, 53 from our own records, 19 from the literature, and six from other data present in GBIF. Of the 78 records, 66 are from the South Shetland Islands, eight are from South Georgia, and four from the CHBR. This database was developed as one of the main objectives of two Chilean-funded research projects addressing understanding the effects of climate change on sub-Antarctic and Antarctic insects. It provides dataset documenting the distribution of Parochlus steinenii in the Maritime Antarctic, the sub-Antarctic, and the CHBR in southern South America (Chile). The complete dataset is available in Darwin Core Archive format via the Global Biodiversity Information Facility (GBIF).

The Development of Gastric Tumours in Drosophila Larvae

Development ◽  
1957 ◽  
Vol 5 (2) ◽  
pp. 143-152
Author(s):  
H. H. El Shatoury ◽  
C. H. Waddington
Keyword(s):  
Salivary Glands ◽  
Alimentary Tract ◽  
Normal Development ◽  
Body Cavity ◽  
The Body ◽  
Wild Type ◽  
Lymph Glands ◽  
Drosophila Larvae ◽  
Hind Gut ◽  
Formation Of Groups

It has been shown that in the normal development of wild-type Drosophila larvae, a process of hypertrophy or proliferation leading to the formation of groups of non-nucleated cellular masses occurs in the mid-gut (stomach) and at the imaginal primordia of the hind-gut and the salivary glands in both the first and second instars (Shatoury & Waddington, 1957b). The process takes place just at the time when the lymph glands hypertrophy and release cells into the body-cavity and the excessive growths of the organs of the alimentary tract regress and are resorbed as soon as the lymph glands become regenerated. The appearances strongly suggest that there is a causal connexion between the proliferation of the lymph glands cells and the hypertrophy which occurs in the gut and salivary glands.

Unregulated Sealing in the Dependencies

2007 ◽  
pp. 61-78
Author(s):  
A.B. Dickinson
Keyword(s):  
Eighteenth Century ◽  
Similar Pattern ◽  
Detailed Account ◽  
South Shetland Islands ◽  
The South ◽  
Shetland Islands ◽  
South Georgia ◽  
Late Eighteenth Century ◽  
Late Eighteenth ◽  
History Of

This chapter provides a detailed account of the growth of the unregulated sealing industry in the Dependencies, in the same format as Chapter Two. It begins with a history of the discovery of South Georgia, and follows the arrival of American and British vessels in late eighteenth century. It follows a similar pattern in the Falklands history, where sealing excursions declined during European and American wars, only to return with vigor from 1810 onwards - devastating seal stocks by the 1820s. The South Georgian sealing industry continued to decline during the nineteenth century, with numerous failed excursions recorded. In counterbalance to this, the South Shetland Islands saw a rise in sealing. A rise in sealing occurred during the brief sea fur boom of the 1860s and 1870s, where the chapter concludes.

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