Pathological changes of stomach in ringed seal (Pusa hispida) from Arviat (North Canada) caused by anisakid nematodes

2013 ◽  
Vol 16 (1) ◽  
pp. 63-67
Author(s):  
Z. Sołtysiak ◽  
M. Simard ◽  
J. Rokicki
Keyword(s):  
Mononuclear Cells ◽  
Gastric Wall ◽  
Ringed Seal ◽  
Gastric Lesions ◽  
Ringed Seals ◽  
Pseudoterranova Decipiens ◽  
Mucosal Layer ◽  
Pusa Hispida ◽  
Contracaecum Osculatum ◽  
Anisakid Nematodes

Abstract This is a report of lesions associated with the nematodes (Anisakidae) from the stomach of ringed seals (Pusa hispida). On thirty one examined ringed seals from Arviat, thirteen were infected by 1 to 24 anisakids. Identification of nematodes from their stomachs showed two species; Contracaecum osculatum (sensu lato) (79 specimens) and Pseudoterranova decipiens (sensu lato) (11 specimens). In the gastric sections with parasites, larvae and adults of nematodes were present mainly in the fundic portion of the stomach. The anterior parts of the nematodes were embedded in mucosa and submucosa. Anisakids were associated with ulcerous gastric lesions and raised inflammatory areas in the stomachs. The histological examination of a sample taken from the tissue surrounding anisakids revealed the presence of more or less confluent focal necrotic areas. Most small petechial hemorrhages were located in the mucosal layer of the gastric wall and were surrounded by inflammatory mononuclear cells such as lymphocytes, histiocytes, eosinophils and fibroblasts. The Anisakidae larvae in the stomach caused atrophy of glands, hemorrhaging and eosinophilic infiltrations that consequently healed, creating fibrotic scars.

Anisakids of seals found on the southern coast of Baltic Sea

2014 ◽  
Vol 59 (1) ◽  
Author(s):  
Michał Skrzypczak ◽  
Jerzy Rokicki ◽  
Iwona Pawliczka ◽  
Katarzyna Najda ◽  
Joanna Dzido
Keyword(s):  
Baltic Sea ◽  
Life Stage ◽  
Adult Life ◽  
Sensu Stricto ◽  
Halichoerus Grypus ◽  
Slight Excess ◽  
Pseudoterranova Decipiens ◽  
Pusa Hispida ◽  
Contracaecum Osculatum ◽  
Anisakid Nematodes

AbstractIn the present study 5 grey seals (Halichoerus grypus), 3 common seals (Phoca vitulina) and 1 ringed seal (Pusa hispida) bycaught or stranded on the Polish Baltic Sea coast in years 2000-2006 were investigated for the infestation of parasitic anisakid nematodes. 749 of anisakids were found. The most common were: Contracaecum osculatum (59.3%) and Pseudoterranova decipiens (31.0%). There were also small numbers of Anisakis simplex (0.8%). After performing RFLP three sibling species were found. C. osculatum was identified as C. osculatum C, P decipiens was identified as P. decipiens sensu stricto and A. simplex — A. simplex sensu stricto. Nematodes found in seals were mostly in L4 and adult life stage — both of them were equal with some minor variations among the specimens. Sex ratio was also equal, but there was slight excess of males in some cases. There was a minority of L3 larvae belonging to A. simplex species (0.8%).

scholarly journals Distribution and abundance of sealworm (Pseudoterranova decipiens) and other anisakid nematodes in fish and seals in the Gulf of St. Lawrence: potential importance of climatic conditions

2001 ◽  
Vol 3 ◽  
pp. 113 ◽  
Author(s):  
David J Marcogliese
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Climatic Conditions ◽  
Pseudoterranova Decipiens ◽  
Nematode Abundance ◽  
Contracaecum Osculatum ◽  
Myoxocephalus Scorpius ◽  
Longhorn Sculpin ◽  
Anisakid Nematodes ◽  
Seal Diet

Prevalence and abundance of sealworm (Pseudoterranova decipiens) and other anisakid nematodes were determined in a variety of fishes from the Gulf of St. Lawrence in 1990 and 1992. Sealworm abundance and prevalence were also determined in three species of seals in the Gulf between 1988 and 1992. Atlantic cod (Gadus morhua) and shorthorn (Myoxocephalus scorpius) and longhorn sculpin (M. octodecemspinosus) were the fishes most heavily infected with sealworm. Grey seals(Halichoerus grypus) proved to be the most important definitive hosts for sealworm in the Gulf. Abundance of sealworm increased, whereas that of Anisakis simplex and contracaecine nematodes decreased, from north to south in the Gulf. Abundance of sealworm increased compared to earlier surveys in most areas of the Gulf, but decreased in both cod and grey seals during the course of this study. In contrast, abundance of Contracaecum osculatum and Phocascaris spp. in grey seals and cod continued to increase during the study period. Observed increases of nematodes are attributed to growing populations of grey seals (for sealworm) and harp seals (for Contracaecinea). Levels of A. simplex remained relatively constant between 1988 and 1992 in both grey seals and cod. There is no evidence suggesting that observed patterns in nematode abundance were due to changes in grey seal diet. Nor was there any evidence of competition between P. decipiens and C. osculatum in grey seals affecting either sealworm abundance or fecundity. The trends detected herein are attributed to climatic events in the Gulf of St. Lawrence, where water temperatures in the cold intermediate layer consistently decreased between 1986 and 1994. It is suggested that low temperatures inhibited development and hatching of sealworm eggs, but not those of C. osculatum.

Comparison between spring and autumn infection by Corynosoma (Acanthocephala) in the ringed seal Pusa hispida in the Bothnian Bay of the Baltic Sea

Parasitology ◽  
1981 ◽  
Vol 82 (2) ◽  
pp. 287-296 ◽  
Author(s):  
Eero Helle ◽  
E. Tellervo Valtonen
Keyword(s):  
Baltic Sea ◽  
Feeding Habits ◽  
Ringed Seal ◽  
The Other ◽  
The Baltic Sea ◽  
Rate Of Development ◽  
Ringed Seals ◽  
Pusa Hispida ◽  
The Baltic ◽  
Bothnian Bay

SUMMARYCorynosoma spp. (Acanthocephala) infection in ringed seals (Pusa hispida) is compared in spring and in autumn in the Bothnian Bay, northern Baltic Sea. The material consists of more than 13400 specimens: 7590 from the intestines of 13 seals captured in April and May 1978 and 5850 from 29 seals captured in October and November.Corynosoma strumosum infection had approximately the same intensity in spring and autumn (mean 76 and 66 individuals/infected seal, maxmum 313 and 324 individuals, respectively). C. semerme specimens, on the other hand, were 37 times more numerous in spring than in autumn (504 compared with 136/infected seal, maximum 1700 and 1230 individuals, respectively). The ratio of C. strumosum to C. semerme was 1:6·3 in spring and 1:2·0 in autumn, as calculated from the total material. Corynosoma infection was more recent on average in spring than in autumn, as judged both from the proportion of males and immature females and from the distribution of C. semerme in the intestine. The feeding habits of the ringed seals and the rate of development of Corynosoma infection are discussed.

Assessment of claw growth-layer groups from ringed seals (Pusa hispida) as biomonitors of inter- and intra-annual Hg, δ15N, and δ13C variation

2011 ◽  
Vol 89 (9) ◽  
pp. 774-784 ◽  
Author(s):  
Elizabeth O. Ferreira ◽  
Lisa L. Loseto ◽  
Steven H. Ferguson
Keyword(s):  
Life History ◽  
Marine Mammals ◽  
Ringed Seal ◽  
The Body ◽  
Conservation Strategies ◽  
Growth Layer ◽  
Annual Variations ◽  
Ringed Seals ◽  
Pusa Hispida ◽  
Layer Groups

The ringed seal ( Pusa hispida (Schreber, 1775)) is a sentinel species of arctic marine mammals; therefore, methods to monitor its life-history changes are crucial to establish effective conservation strategies. We evaluate the potential use of claws of ringed seals as a proxy for counts of tooth growth-layer groups (age) and a biomonitor of total mercury burden (THg) and diet (stable isotope ratios expressed as δ15N and δ13C). The count of claw growth-layer groups was indicative of age up to 8 years and we infer differentiation of dark and light annuli as being associated with the spring moult. No differences of THg, δ15N, or δ13C were observed among flipper digits. The proximal claw annulus representing the most recent growth had δ13C values that were correlated to both muscle and liver δ13C, supporting the use of claws to monitor visceral δ13C. Claw log10THg from the proximate annulus was significantly correlated to liver and whisker log10THg, while significant interannual THg accumulation was observed in 18 of 32 seals ≥4 years, suggesting the claws receive and disperse Hg from active tissues of the body. Results support the use of claw tissue from ringed seal to provide a chronological record of inter- and intra-annual variations representing seal diet, contaminant load, and life history.

scholarly journals Contracaecum osculatumand other anisakid nematodes in grey seals and cod in the Baltic Sea: molecular and ecological links

2017 ◽  
Vol 92 (1) ◽  
pp. 81-89 ◽  
Author(s):  
S. Zuo ◽  
P.W. Kania ◽  
F. Mehrdana ◽  
M.H. Marana ◽  
K. Buchmann
Keyword(s):  
Baltic Sea ◽  
Gadus Morhua ◽  
Final Host ◽  
The Baltic Sea ◽  
Fish Stocks ◽  
Pseudoterranova Decipiens ◽  
Contracaecum Osculatum ◽  
The Baltic ◽  
The Impact ◽  
Anisakid Nematodes

AbstractPopulations of grey seals (Halichoerus grypus), sprats (Sprattus sprattus) and cod (Gadus morhua) in the Baltic Sea are relatively stationary. The present work, applying classical and molecular helminthological techniques, documents that seals and cod also share a common parasite, the anisakid nematodeContracaecum osculatum, which uses seals as the final host and fish as transport hosts. Sequencing mitochondrial genes (COX1andCOX2) in adult worms from seals and third-stage larvae from livers of Baltic fish (sprats and cod), showed that all gene variants occur in both seals and fish. Other anisakid nematodesPseudoterranova decipiensandAnisakis simplexare also found in both seals and cod in the Baltic Sea, but at much lower rates. The Baltic grey seal population was left at a critically low level (comprising a few hundred individuals) during the latter part of the 20th century, but since the year 2000 a marked increase in the population has been observed, reaching more than 40,000 individuals at present. Ecological consequences of the increased seal abundance may result from increased predation on fish stocks, but recent evidence also points to the influence of elevated parasitism on fish performance.Contracaecum osculatumlarvae preferentially infect the liver of Baltic cod, considered a vital organ of the host. Whereas low prevalences and intensities in cod were reported during the 1980s and 1990s, the present study documents 100% prevalence and a mean intensity of above 80 worms per fish. Recent studies have also indicated the zoonotic potential ofC. osculatumlarvae in fish, following the consumption of raw or under-cooked fish. Therefore the present work discusses the impact of parasitism on the cod stock and the increasing risk for consumer health, and lists possible solutions for control.

scholarly journals Spring distribution of ringed seals (Pusa hispida) in Eclipse Sound and Milne Inlet, Nunavut: implications for potential ice-breaking activities

2019 ◽  
Vol 5 (1) ◽  
pp. 54-61 ◽  
Author(s):  
David J. Yurkowski ◽  
Brent G. Young ◽  
J. Blair Dunn ◽  
Steven H. Ferguson
Keyword(s):  
Iron Ore ◽  
Policy Decision ◽  
Resource Development ◽  
Ringed Seal ◽  
Mitigation Strategies ◽  
Decision Makers ◽  
Sea Ice Extent ◽  
Ringed Seals ◽  
Aerial Surveys ◽  
Pusa Hispida

Resource development in Arctic waters is proceeding rapidly leading to increased interactions with Arctic wildlife. As sea ice extent decreases, the demand for shipping and ice-breaking operations will expand into winter and spring with greater impact on ice-dependent pinnipeds. However, knowledge of the distribution of these species, such as ringed seals (Pusa hispida (Schreber, 1775)), during spring within areas of resource development is lacking. Baffinland Iron Mines Corporation’s Mary River iron ore port in southern Milne Inlet, Nunavut opened in 2015 with proposed ice-breaking activities in spring — an important period in ringed seal seasonal life-history. We conducted infrared and photographic aerial surveys in June 2016 and 2017 to overlay the proposed ice-breaking route with ringed seal hotspots (i.e., areas of higher density). We identified four areas of overlap where proposed ice-breaking would traverse through ringed seal hotspots: eastern and western Eclipse Sound (a ringed seal pupping ground identified by local knowledge), the middle of Milne Inlet, and southern Milne Inlet. We identified potential negative implications of spring ice-breaking operations on ringed seals such as displacement, separation of mothers and pups, destruction of resting and birth lairs, and vessel–seal collisions. Results are relevant to policy decision-makers who can develop mitigation strategies in the rapidly melting and developing Arctic.

scholarly journals Growth and population parameters of ringed seals (Pusa hispida) from Svalbard, Norway, 2002–2004

2006 ◽  
Vol 63 (6) ◽  
pp. 1136-1144 ◽  
Author(s):  
Bjørn A. Krafft ◽  
Kit M. Kovacs ◽  
Anne Kirstine Frie ◽  
Tore Haug ◽  
Christian Lydersen
Keyword(s):  
Ringed Seal ◽  
The Arctic ◽  
Strong Impact ◽  
Climate Change Scenarios ◽  
Population Parameters ◽  
Ringed Seals ◽  
Asymptotic Values ◽  
Seal Population ◽  
Pusa Hispida ◽  
Sexually Mature

AbstractSamples were collected in Svalbard, Norway, during April and May 2002–2004 from 272 ringed seals (Pusa hispida; 62.5% males, 37.5% females) to study growth and population parameters. The age of the animals ranged from 1 to 32 years. Asymptotic values for standard length and body mass were 127.7 ± 1.6 (s.e.) cm and 69.0 ± 2.7 kg for males (maxima: 144 cm and 92 kg) and 127.6 ± 2.3 cm and 68.9 ± 2.5 kg for females (maxima: 141 cm and 91 kg). All animals were sexually mature at an age ≥6 years and the ovulation rate was 0.86. Mean Age at Maturity (MAM) was 4.2 ± 0.2 years for males and 3.5 ± 0.3 years for females, values significantly lower than calculated for ringed seals from the same area 20 years ago. This change in MAM suggests that either the prey base for ringed seals in the area has increased or alternatively that the density of ringed seals has declined, such that more resources are available per capita. If the climate of the Arctic changes in the manner predicted by a host of climate-change scenarios, it is likely to have a strong impact on ringed seal populations in future, although there are no data to suggest that dramatic changes have taken place yet in fish and invertebrate populations in the Svalbard area. Although cause-and-effect cannot be firmly established, there is a possibility that the substantial increase in the number of polar bears (Ursus maritimus) over the past 20 years, since hunting the species in Svalbard ceased in 1973, may have played a role in the observed change in the ringed seal population.

scholarly journals Ringed seal (Pusa hispida) breeding habitat on the landfast ice in northwest Alaska during spring 1983 and 1984

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0260644
Author(s):  
Donna D. W. Hauser ◽  
Kathryn J. Frost ◽  
John J. Burns
Keyword(s):  
Sea Ice ◽  
Marine Mammals ◽  
Environmental Changes ◽  
Chukchi Sea ◽  
Ringed Seal ◽  
Breeding Habitat ◽  
Future Research ◽  
Ringed Seals ◽  
Pusa Hispida ◽  
Kotzebue Sound

There has been significant sea ice loss associated with climate change in the Pacific Arctic, with unquantified impacts to the habitat of ice-obligate marine mammals such as ringed seals (Pusa hispida). Ringed seals maintain breathing holes and excavate subnivean lairs on sea ice to provide protection from weather and predators during birthing, nursing, and resting. However, there is limited baseline information on the snow and ice habitat, distribution, density, and configuration of ringed seal structures (breathing holes, simple haul-out lairs, and pup lairs) in Alaska. Here, we describe historic field records from two regions of the eastern Chukchi Sea (Kotzebue Sound and Ledyard Bay) collected during spring 1983 and 1984 to quantify baseline ringed seal breeding habitat and map the distribution of ringed seal structures using modern geospatial tools. Of 490 structures located on pre-established study grids by trained dogs, 29% were pup lairs (25% in Kotzebue Sound and 33% in Ledyard Bay). Grids in Ledyard Bay had greater overall density of seal structures than those in Kotzebue Sound (8.6 structures/km2 and 7.1 structures/km2), but structures were larger in Kotzebue Sound. Pup lairs were located in closer proximity to other structures and characterized by deeper snow and greater ice deformation than haul-out lairs or simple breathing holes. At pup lairs, snow depths averaged 74.9 cm (range 37–132 cm), with ice relief nearby averaging 76 cm (range 31–183 cm), and ice deformation 29.9% (range 5–80%). We compare our results to similar studies conducted in other geographic regions and discuss our findings in the context of recent declines in extent and duration of seasonal cover of landfast sea ice and snow deposition on sea ice. Ultimately, additional research is needed to understand the effects of recent environmental changes on ringed seals, but our study establishes a baseline upon which future research can measure pup habitat in northwest Alaska.

Population parameters of ringed seals (Phoca hispida Schreber, 1775) in the Svalbard area

1987 ◽  
Vol 65 (4) ◽  
pp. 1021-1027 ◽  
Author(s):  
Christian Lydersen ◽  
Ian Gjertz
Keyword(s):  
Sex Ratio ◽  
Ringed Seal ◽  
Adult Males ◽  
Population Parameters ◽  
Phoca Hispida ◽  
Age Class ◽  
Ringed Seals ◽  
Males And Females ◽  
The Mean ◽  
Sexually Mature

Samples were taken from 284 ringed seals (Phoca hispida) in the Svalbard area during April–July 1981 and March–April 1982. The age of 283 seals was determined by reading annuli in the cementum of the canine teeth. The mean age of the males was 11.3 years, and of the females, 14.9 years. Females were found to be significantly older than males. The mean length of sexually mature ringed seals was 128.9 cm for both sexes. The mean weight of adult males and females was 53.5 and 61.4 kg, respectively. Females were found to be significantly heavier than males. The sex ratio was 47.8% males and 52.2% females. Studies of microscopic sections of testis and epididymis from ringed seal males showed that 63, 75, and 80% of 5-, 6-, and 7-year-old animals, respectively, were sexually mature. The weights of testis and epididymis, diameters of tubuli, and the size of testis all showed a marked increase in the 5-year age-class. Macroscopic sections of ovaries from ringed seal females showed that 20, 60, and 80% of 3-, 4-, and 5-year-old animals, respectively, were sexually mature. The size of the ovaries showed a marked increase in the 5-year age-class. The ovulation rate of ringed seals from Svalbard was calculated to be 0.91.

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