scholarly journals Lighten up the dark: metazoan parasites as indicators for the ecology of Antarctic crocodile icefish (Channichthyidae) from the north-west Antarctic Peninsula

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4638 ◽  
Author(s):  
Thomas Kuhn ◽  
Vera M.A. Zizka ◽  
Julian Münster ◽  
Regina Klapper ◽  
Simonetta Mattiucci ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
South Shetland Island ◽  
Stomach Contents ◽  
Biological Indicators ◽  
Parasite Fauna ◽  
Metazoan Parasites ◽  
North West ◽  
The North ◽  
West Antarctic ◽  
Taxonomic Groups

Due to its remote and isolated location, Antarctica is home to a unique diversity of species. The harsh conditions have shaped a primarily highly adapted endemic fauna. This includes the notothenioid family Channichthyidae. Their exceptional physiological adaptations have made this family of icefish the focus of many studies. However, studies on their ecology, especially on their parasite fauna, are comparatively rare. Parasites, directly linked to the food chain, can function as biological indicators and provide valuable information on host ecology (e.g., trophic interactions) even in remote habitats with limited accessibility, such as the Southern Ocean. In the present study, channichthyid fish (Champsocephalus gunnari: n = 25, Chaenodraco wilsoni: n = 33, Neopagetopsis ionah: n = 3, Pagetopsis macropterus: n = 4, Pseudochaenichthys georgianus: n = 15) were collected off South Shetland Island, Elephant Island, and the tip of the Antarctic Peninsula (CCAML statistical subarea 48.1). The parasite fauna consisted of 14 genera and 15 species, belonging to the six taxonomic groups including Digenea (four species), Nematoda (four), Cestoda (two), Acanthocephala (one), Hirudinea (three), and Copepoda (one). The stomach contents were less diverse with only Crustacea (Euphausiacea, Amphipoda) recovered from all examined fishes. Overall, 15 new parasite-host records could be established, and possibly a undescribed genotype or even species might exist among the nematodes.

Bellingshausen and the discovery of Antarctica

Polar Record ◽  
1971 ◽  
Vol 15 (99) ◽  
pp. 887-889 ◽  
Author(s):  
Terence Armstrong
Keyword(s):  
Antarctic Peninsula ◽  
West Coast ◽  
North West ◽  
The North ◽  
Antarctic Continent ◽  
The Antarctic

For the last twenty years there has been considerable Soviet interest in the circumnavigation of Antarctica by the Russian naval expedition of 1819–21, led by Captain T. T. Bellingshausen, with Lieut M. P. Lazarev as his second in command, in the sloops Vostok and Mirnyy. It is now reasonably certain that Bellingshausen sighted the Antarctic continent several times, notably on 27 January 1820 (New Style) at a point about lat 69°21′S, long 2°14′W, and was thus the first to see it (Edward Bransfield sighted the north-west coast of the Antarctic Peninsula at about lat 63°50′S, long 60°30′W on 30 January 1820, three days later). Bellingshausen did not claim to have done so however, but his descriptions of what he saw tally very well with what the edge of the continent here is now known to look like. There is one relatively new point. Bellingshausen's first sighting has been moved forward one day, from the 28th to the 27th, because it has been shown that he was keeping ship's time, from mid-day to mid-day, and therefore that what his log called the 28th (his sighting being in the second half of the day) was what the civil calendar would call the 27th (Belov, 1963, p 19–29). All this much is well documented and unlikely to be disputed. The question is, how much importance did he, and his contemporaries, attach to this discovery? And did he realize that he had seen the edge of a continent? Recent Soviet studies have sought to show that he had a very good idea of the importance of what he had seen, and that this idea did get through to his contemporaries. It is here that there is room for argument with the Soviet scholars.

scholarly journals Effect of salt and temperature stresses on survival and infectivity of Heterorhabditis spp. IJs

Nematology ◽  
1999 ◽  
Vol 1 (1) ◽  
pp. 69-78 ◽  
Author(s):  
Michelle M. Finnegan ◽  
Martin J. Downes ◽  
Myra O'Regan ◽  
Christine T. Griffin
Keyword(s):  
High Temperature ◽  
Nous Avons ◽  
Elevated Temperatures ◽  
Galleria Mellonella ◽  
High Salinity ◽  
Sea Water ◽  
Aqueous Suspension ◽  
North West ◽  
The North ◽  
Taxonomic Groups

Abstract Heterorhabditis is frequently found in coastal sandy soils where it may experience both high salinity and high temperatures. We tested the ability of infective juveniles (IJs) of three taxonomic groups of Heterorhabditis to infect insects in saline sand. We also tested whether salinity (sea water) affected the IJs' ability to tolerate elevated temperatures in aqueous suspension and in sand. IJs of all three taxonomic groups killed Galleria mellonella in saline sand (25.6% insects killed), but at a lower level than in non-saline sand (96.5% insects killed). Exposure of IJs in sand to high temperature reduced their ability to kill G. mellonella at 20 degrees C; heating IJs in saline sand reduced G. mellonella mortality to a lesser extent (25.6% at 20 degrees C, 18.3% at 39 degrees C) than heating in non-saline sand (96.5% at 20 degrees C, 17.5% at 39 degrees C). In aqueous suspension, IJs of the North-West European and Irish types of Heterorhabditis tolerated high temperature better in sea water (at least 95% survived 1 h at 39 C) than in distilled water (none survived 1 h at 38 degrees C). H. bacteriophora was more temperature tolerant: survival and subsequent infectivity of IJs was unaffected by temperature up to 39 degrees C in either medium. It was concluded that high salinity (sea water) reduces the ability of Heterorhabditis IJs to infect, but improves their tolerance of high temperature. Effets des chocs dus a la salinite et a la temperature sur la survie et l'infestivite des juveniles infestants d' Heterorhabditis spp. - Les Heterorhabditis sont frequemment rencontres dans les sols sableux cotiers ou ils peuvent etre soumis a des salinites et des temperatures elevees. Nous avons teste la capacite des juveniles infestants (IJs) de trois groupes taxinomiques d'Heterorhabditis a infester des insectes dans du sable sale. Nous avons aussi cherche a savoir si la salinite (eau de mer) affecte la capacite des IJs a tolerer des temperatures elevees, soit en suspension aqueuse, soit dans du sable. Les IJs des trois troupes taxinomiques tuent les Galleria mellonella dans le sable sale, mais a un taux plus faible que dans le sable non sale (25,6 contre 96,5% des insectes tues). L'exposition des IJs dans du sable a des temperatures elevees reduit leur capacite a tuer G. mellonella a 20 degrees C; le chauffage des IJs dans du sable sale reduit la mortalite des G. mellonella dans un moindre mesure (25,6 a 20 degrees C contre 18,3% a 39 degrees C) que dans du sable non sale (96,5% a 20 degrees C contre 17,5% a 39 degrees C). En suspension aqueuse, les IJs des types Europe du nord-ouest et d'Irlande tolerent mieux les temperatures elevees dans l'eau de mer (au moins 95% survivent 1 h a 39 degrees C) que dans l'eau distillee (aucune survie apres 1 h a 38 degrees C). H. bacteriophora montre la meilleure tolerance a la temperature: la survie et l'infestivite ulterieures des IJs ne sont pas affectees par la temperature jusqu'a 39 degrees C dans l'un et l'autre milieux. Il en est conclu que les salinites elevees (eau de mer) reduisent la capacite d'infestation des IJs d'Heterorhabditis, mais ameliorent leur tolerance aux temperatures elevees.

scholarly journals Reproductive biology and diet of the grey sharpnose shark Rhizoprionodon oligolinx Springer, 1964 (Chondrichthyes: Carcharhinidae) from the north-eastern Arabian Sea

2017 ◽  
Vol 64 (4) ◽  
Author(s):  
G. B. Purushottama ◽  
Thakurdas . ◽  
V. Ramasubramanian ◽  
Gnyanaranjan Dash ◽  
K. V. Akhilesh ◽  
...  
Keyword(s):  
Reproductive Biology ◽  
Arabian Sea ◽  
Stomach Contents ◽  
Size At Maturity ◽  
Dietary Analysis ◽  
North West ◽  
The North ◽  
Northern Arabian Sea ◽  
North Eastern ◽  
Relationship Of

Information on reproductive biology is presented for the grey sharpnose shark Rhizoprionodon oligolinx Springer, 1964 (Chondrichthyes: Carcharhiniformes), collected off the north-west coast of India in the Arabian Sea. A total of 711 individuals, of 27.0 to 93.0 cm total length (TL), 180 to 2600 g total weight (TW) were used for the study. The lengthweight relationships were significantly different between the sexes. The size-at  maturity (Lm50) for females and males was estimated to be 62.3 and 59.5 cm TL respectively. Number of embryos ranged from 1 to 7 and the size at birth was estimated between 25 to 30 cm TL. Overall sex ratio favoured the females slightly at the rate of 1.27:1. There was significant positive correlation between maternal TL and number of embryos (p<0.001). Dietary analysis of stomach contents (%IRI) revealed that R. oligolinx feeds primarily on teleosts (95.5%), cephalopods (3.2%) and crustaceans (1.2%). This study presents the first detailed biological observation on size, sex composition, size-at-maturity (Lm50) and length-weight relationship of R. oligolinx from the northern Arabian Sea.

scholarly journals Biological observations on the Bengal guitarfish Rhinobatos annandalei Norman, 1926 from the Eastern Arabian Sea, India

2020 ◽  
Vol 67 (2) ◽  
Author(s):  
G. B. Purushottama ◽  
V. Ramasubramanian ◽  
K. V. Akhilesh ◽  
S. G. Raje Thakurdas ◽  
Shobha Joe Kizhakudan ◽  
...  
Keyword(s):  
Arabian Sea ◽  
Stomach Contents ◽  
Iucn Red List ◽  
Biological Data ◽  
Effective Management ◽  
Single Female ◽  
North West ◽  
The North ◽  
Data Deficient ◽  
Size At Birth

Biological data for the little known Bengal guitarfish Rhinobatos annandalei Norman, 1926 (Rhinopristiformes: Rhinobatidae) are presented based on specimens collected from bycatch of commercial shrimp trawlers, gill netters and bag or dol netters operating in the Arabian Sea at depths of 2-70 m off the north-west coast of India. Five hundred ninety-three specimens measuring 30.0 to 95.0 cm total length (TL) and weighing between 64.0 to 3300 g total weight (TW) were collected for the study. The length-weight relationships (LWR) were significantly different between the sexes (p<0.001) and for the combined sexes was derived as TW= 0.000604 TL3.408256 (r2= 0.997). The co-efficients ‘a’, ‘b’ of the LWR were estimated as 0.000621, 3.410115 (r2= 0.999) for females and 0.000766, 3.333872 (r2= 0.999) for males. The length at maturity (TL50) for females and males was estimated to be 61.0 and 63.3 cm TL, respectively. In a single female, the number of embryos ranged from 2 to 11 and the size at birth was estimated between 25.0 to 30.0 cm TL. The overall sex ratio favoured females at the rate of 1.6:1. An analysis of the stomach contents (%IRI) revealed that R. annandalei mainly fed on Solenocera spp. (18.7% IRI), along with P. sculptilis (0.5% IRI), P. stylifera (0.4% IRI), Loligo spp. (0.4% IRI) and sciaenids (0.3% IRI). Since, the species is poorly studied and assessed as ‘Data Deficient’ in the IUCN red list criterion, it is anticipated that the biological results from the present study, will update information on the species thereby enabling more effective management decisions.

Effects of giant icebergs on two emperor penguin colonies in the Ross Sea, Antarctica

2007 ◽  
Vol 19 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Gerald L. Kooyman ◽  
David G. Ainley ◽  
Grant Ballard ◽  
Paul J. Ponganis
Keyword(s):  
Ross Sea ◽  
Emperor Penguin ◽  
Ice Shelf ◽  
West Antarctic Ice Sheet ◽  
North West ◽  
Ross Ice Shelf ◽  
The North ◽  
West Antarctic ◽  
South West ◽  
Wintering Areas

The arrival in January 2001 in the south-west Ross Sea of two giant icebergs, C16 and B15A, subsequently had dramatic affects on two emperor penguin colonies. B15A collided with the north-west tongue of the Ross Ice Shelf at Cape Crozier, Ross Island, in the following months and destroyed the penguins' nesting habitat. The colony totally failed in 2001, and years after, with the icebergs still in place, exhibited reduced production that ranged from 0 to 40% of the 1201 chicks produced in 2000. At Beaufort Island, 70 km NW of Crozier, chick production declined to 6% of the 2000 count by 2004. Collisions with the Ross Ice Shelf at Cape Crozier caused incubating adults to be crushed, trapped in ravines, or to abandon the colony and, since 2001, to occupy poorer habitat. The icebergs separated Beaufort Island from the Ross Sea Polynya, formerly an easy route to feeding and wintering areas. This episode has provided a glimpse of events which have probably occurred infrequently since the West Antarctic Ice Sheet began to retreat 12 000 years ago. The results allow assessment of recovery rates for one colony decimated by both adult and chick mortality, and the other colony by adult abandonment and chick mortality.

Feeding ecology of Cuvier's beaked whale (Ziphius cavirostris): a review with new information on the diet of this species

2001 ◽  
Vol 81 (4) ◽  
pp. 687-694 ◽  
Author(s):  
M.B. Santos ◽  
G.J. Pierce ◽  
J. Herman ◽  
A. López ◽  
A. Guerra ◽  
...  
Keyword(s):  
Stomach Contents ◽  
Sperm Whales ◽  
Important Species ◽  
North West ◽  
North East ◽  
The North ◽  
New Information ◽  
Beaked Whales ◽  
Ziphius Cavirostris ◽  
Cuvier’S Beaked Whale

Published information on the diet of Cuvier's beaked whales Ziphius cavirostris (Odontoceti: Ziphiidae) is reviewed and new information on the stomach contents of three animals: two stranded in Galicia (north-west Spain) in February 1990 at A Lanzada, and in February 1995 at Portonovo; and the third stranded in February 1999 in North Uist (Scotland), is presented. The whale stranded in 1990 was a male; the other two were adult females. All animals were >5 m long.  The limited published information on the diet of this species indicates that it feeds primarily on oceanic cephalopods although some authors also found remains of oceanic fish and crustaceans.  Food remains from the three new samples consisted entirely of cephalopod beaks. The Scottish sample set is the largest recorded to date for this species. The prey identified consisted of oceanic cephalopods, mainly squid (Cephalopoda: Teuthoidea). The most frequently occurring species were the squid Teuthowenia megalops, Mastigoteuthis schmidti and Taoniuspavo (for the Galician whale stranded in 1990), Teuthowenia megalops and Histioteuthis reversa (for the second Galician whale) and T. megalops, Gonatus sp. and Taoniuspavo (for the Scottish whale). Other prey included the squid Histioteuthis bonnellii, Histioteuthis arcturi and Todarodes sagittatus as well as Vampiroteuthis infernalis (Cephalopoda: Vampyromorpha), Stauroteuthis syrtensis and Japetella diaphana (Cephalopoda: Octopoda). The squid eaten (estimated from the measurement of the lower beaks) included juvenile and mature individuals of the most important species (Teuthowenia megalops, Gonatus sp.).  The range of species found in the diet of Z. cavirostris is greater than that reported for sperm whales and bottlenosed whales in the north-east Atlantic.

scholarly journals The Catacomb Cultures of the North-West Caspian Steppe: 14C Chronology, Reservoir Effect, and Paleodiet

Radiocarbon ◽  
2007 ◽  
Vol 49 (2) ◽  
pp. 713-726 ◽  
Author(s):  
N I Shishlina ◽  
J van der Plicht ◽  
R E M Hedges ◽  
E P Zazovskaya ◽  
V S Sevastyanov ◽  
...  
Keyword(s):  
Bronze Age ◽  
Stomach Contents ◽  
Bone Collagen ◽  
Stable Isotope Ratios ◽  
Radiocarbon Dates ◽  
Bone Material ◽  
Reservoir Effect ◽  
North West ◽  
The North ◽  
The Bronze Age

For the Bronze Age Catacomb cultures of the North-West Caspian steppe area in Russia, there is a conflict between the traditional relative archaeological chronology and the chronology based on radiocarbon dates. We show that this conflict can be explained largely by the fact that most dates have been obtained on human bone material and are subject to 14C reservoir effects. This was demonstrated by comparing paired 14C dates derived from human and terrestrial herbivore bone collagen. In addition, values of stable isotope ratios (δ13C and δ15N) and analysis of food remains from vessels and the stomach contents of buried individuals indicate that a large part of the diet of these cultures consisted of fish and mollusks, and we conclude that this is the source of the reservoir effect.

Metazoan parasites of cod, Gadus morhua L., in Canadian Atlantic waters

1982 ◽  
Vol 60 (7) ◽  
pp. 1573-1579 ◽  
Author(s):  
R. G. Appy ◽  
M. D. B. Burt
Keyword(s):  
North Atlantic ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Parasite Fauna ◽  
Marine Fishes ◽  
Metazoan Parasites ◽  
The North ◽  
Wide Range ◽  
Enteric Parasites ◽  
The North Atlantic

From July to September 1975, 739+ Atlantic cod, Gadus morhua L., were collected in the Bay of Fundy, Nova Scotia shelf, and southern Gulf of St. Lawrence and were examined for metazoan paraties. Of 49 parasites recorded, 10 were considered more or less specific to cod or related gadid hosts, 9 were considered accidental infections, and the remaining majority of parasites were apparently capable of infecting a wide range of unrelated marine fishes. The general lack of strict host specificity of enteric parasites of northern marine fishes results in a very diverse parasite fauna in fish such as cod which have very broad feeding habits.Metazoan parasites recorded from cod were mostly arctic–boreal transatlantic and amphiboreal species. No species endemic to the northwestern Atlantic were found. However, among all metazoan parasites which are restricted to gadid hosts, there are more endemic species in the North Atlantic, particularly the northwestern Atlantic than present in the North Pacific. This distribution surely reflects the large number of endemic gadid genera and species in the North Atlantic and the probable Atlantic–Arctic origin of the Gadidae.

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