scholarly journals Sealworm (Pseudoterranova decipiens) dynamics in Sable Island grey seals (Halichoerus grypus): seasonal fluctuations and other changes in worm infections during the 1980s

2001 ◽  
Vol 3 ◽  
pp. 129
Author(s):  
Wayne T Stobo ◽  
G Mark Fowler
Keyword(s):  
Seasonal Pattern ◽  
Infected Fish ◽  
Field Trips ◽  
First Year ◽  
Pseudoterranova Decipiens ◽  
Seal Population ◽  
Contracaecum Osculatum ◽  
Substantial Decline ◽  
First Year Of Life ◽  
Sexually Mature

The abundance of P. decipiens sampled from the stomachs of 553 grey seals (aged 0-48 years) collected during 14 field trips to Sable Island in 1983 and 1989 did not change significantly between years, even though the seal population has been increasing at over 12% annually and there has been a substantial decline in the fish biomass upon which they depend. The proportion of mature worms in the seals’ stomachs has decreased, however. Seal growth, expressed in terms of either age orlength, showed the strongest correlation with total worm abundance. These infections were not completely eliminated at any time during the year, but a seasonal pattern in worm abundance was apparent. Among the youngest seals an inverse relationship was demonstrated between the abundance of P. decipiens and another parasitic nematode, Contracaecum osculatum. Sexually mature P. decipiens were found in pups within 3 to 4 months of the commencement of independent feeding, and the abundance of P. decipiens progressively increased throughout the first year of life. Male pups contracted more worms than female pups of the same age. P. decipiens abundances in juvenile seals were primarily associated with seasonal pattern and age, with C. osculatum abundance still influencing the abundance of P. decipiens, but to a much lesser extent than seen with pups. Length of seals was the main predictor of total worm abundance in adult seals, with a seasonal pattern being next in order of importance. Age was also significant, possibly representing a component of growth not accounted for by length alone. No relationship between the abundances of P. decipiens and C. osculatum was apparent for adult seals. The seasonal pattern in total worm abundance of juvenile and adult seals was characterized by declines during the winter and mid-summer. We suggest these declines are due, respectively, to the breeding season fast and one or both of 1) a change in seal diet from primarily highly infected fish species to less infected ones, and 2) a partial fast during the annual moult. The proportion of mature worms increased during reductions in worm abundance throughout most of the year, but during the breeding fast both total abundance and the proportionmature declined.

Abundance and maturity of three species of parasitic anisakine nematodes (Pseudoterranova decipiens, Contracaecum osculatum, Anisakis simplex) occurring in Sable Island harbour seals (Phoca vitulina)

2002 ◽  
Vol 80 (3) ◽  
pp. 442-449 ◽  
Author(s):  
Wayne T Stobo ◽  
L Paul Fanning ◽  
Brian Beck ◽  
G Mark Fowler
Keyword(s):  
Prey Species ◽  
Phoca Vitulina ◽  
Final Host ◽  
Anisakis Simplex ◽  
Halichoerus Grypus ◽  
Commercial Fish ◽  
Pseudoterranova Decipiens ◽  
Harbour Seals ◽  
Seal Population ◽  
Contracaecum Osculatum

Three species of anisakine nematodes (Pseudoterranova decipiens, Contracaecum osculatum, Anisakis simplex) co-occur in the stomachs of Sable Island harbour seals (Phoca vitulina). The sealworm, P. decipiens, was the commonest nematode in these seals. Anisakis simplex was found in much smaller numbers, none mature, indicating that the harbour seal is not a true final host to this parasite. Contracaecum osculatum was rare but half were mature. Pseudoterranova decipiens increased in abundance with size of the seal. An inverse relationship was observed between P. decipiens abundance and the age of seals of similar size, probably owing to changes in diet. Numbers of P. decipiens may have declined over the summer, coincident with an increase in the proportion of mature worms in the stomach. From similarities between the worm infections of grey seals (Halichoerus grypus) and harbour seals, we infer that A. simplex abundance may also exhibit a decline in abundance. Contracaecum osculatum was only encountered during the latter half of the year, suggesting an association with prey species of corresponding periodicity in their distribution. We estimate that the abundance of sealworm in harbour seals is about 2.5% of that carried by the grey seal population. This could imply that harbour seals represent an insignificant vector of the sealworm infecting commercial fish species in the Northwest Atlantic, provided density-dependent relationships exist between worm abundances in different host species.

Life History of the Endemic Saddleback Crayfish, Faxonius medius (Faxon, 1884), (Decapoda: Cambaridae) in Missouri, USA

2019 ◽  
Vol 24 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Robert DiStefano ◽  
Jacob Westhoff ◽  
Christopher Rice ◽  
Amanda Rosenberger
Keyword(s):  
Life History ◽  
Sympatric Species ◽  
First Year ◽  
Geographic Context ◽  
Ratio Size ◽  
Small Streams ◽  
History Of ◽  
Egg Brooding ◽  
First Year Of Life ◽  
Sexually Mature

Abstract The saddleback crayfish, Faxonius medius (Faxon, 1884), is endemic to a single drainage in eastern Missouri, USA, that is affected by heavy metals mining, and adjacent to a rapidly-expanding urban area. We studied populations of F. medius in two small streams for 18 months to describe the annual reproductive cycle and gather information about fecundity, sex ratio, size at maturity, and size-class structure. We also obtained information about the species’ density at supplemental sites. The species, though rare in a geographic context, is locally abundant; we captured a monthly average of more than 75 F. medius from each of the two study populations. Densities of F. medius were high relative to several sympatric species of Faxonius Cope, 1872 and Cambarus Erichson, 1846. The species exhibited traits of an r-strategist life history; it was relatively short-lived and early to maturity. Its fecundity and egg size were comparable to Ozark congeners. Breeding season occurred in autumn, perhaps extending into early winter. Egg brooding occurred primarily in April. Young-of-year first appeared in samples in June. We estimated that these populations contained 2 to 3 size-classes, and most individuals became sexually mature in their first year of life. Life history information presented herein will be important for future conservation efforts.

scholarly journals Sealworm (Pseudoterranova decipiens) infection in the benthic cottid (Taurulus bubalis) in relation to population increase of harbour seal (Phoca vitulina) in Skagerrak, Sweden

2001 ◽  
Vol 3 ◽  
pp. 47 ◽  
Author(s):  
Sven-Gunnar Lunneryd ◽  
Karl Inne Ugland ◽  
Paul Eric Aspholm
Keyword(s):  
Gadus Morhua ◽  
Final Host ◽  
Infected Fish ◽  
Harbour Seal ◽  
Population Increase ◽  
Threshold Size ◽  
Pseudoterranova Decipiens ◽  
Harbour Seals ◽  
Seal Population ◽  
Benthic Fishes

In Koster archipelago (northern Skagerrak, Sweden) the harbour seal population increased from approximately 350 to more than 1000 individuals between 1988 and 1998. During the same period, sealworm (Pseudoterranova decipiens) abundance in the most heavily infected fish species, bullrout (Myoxocepahulus scorpius) and sea scorpion (Taurulus bubalis), did not increase. Since harbour seals do not normally feed on those cottids an infection route via cod (Gadus morhua), which consume cottids, is proposed. The abundance of sealworm in the final host is therefore related to the probability of cod preying on infected cottids prior to being preyed upon by seals. Our model predictsthat the abundance of larval sealworm in benthic fishes is not related to the number of seals when the colony is over a specific threshold size.

Why Was Infant Mortality So High in Eastern England in the Mid Nineteenth Century?

2015 ◽  
pp. 48-66 ◽  
Author(s):  
Andrew Hinde ◽  
Victoria Fairhurst
Keyword(s):  
Women Workers ◽  
Infant Mortality ◽  
Rural Areas ◽  
Seasonal Pattern ◽  
Historical Context ◽  
Poor Quality ◽  
Early Years ◽  
Annual Reports ◽  
First Year ◽  
First Year Of Life

This paper re-examines the high rates of infant mortality observed in rural areas of eastern England in the early years of civil registration. Infant mortality rates in some rural registration districts in the East Riding of Yorkshire, Cambridgeshire and Norfolk were higher than those in the mill towns of Lancashire. After describing the areas affected, this paper considers three potential explanations: environmental factors, poor-quality child care associated with the employment of women in agriculture, and the possibility that the high rates were the artefactual consequence of migrant women workers bringing their children to these areas. These explanations are then assessed using a range of evidence. In the absence of reliable cause of death data, recourse is had to three alternative approaches. The first involves the use of the exceptionally detailed tabulations of ages at death within the first year of life provided in the Registrar General's Annual Reports for the 1840s to assess whether the 'excess' infant deaths in rural areas of eastern England happened in the immediate post-natal period or later in the first year of life. Second, data on the seasonality of mortality in the 1840s are examined to see whether the zone of 'excess' infant mortality manifested a distinctive seasonal pattern. Finally, a regression approach is employed involving the addition of covariates to regression models. The conclusion is that no single factor was responsible for the 'excess' infant mortality, but a plausible account can be constructed which blends elements of all three of the potential explanations mentioned above with the specific historical context of these areas of eastern England.

The Development of Swallowing Respiratory Coordination

2009 ◽  
Vol 18 (1) ◽  
pp. 19-24
Author(s):  
Maggie-Lee Huckabee
Keyword(s):  
Cortical Activation ◽  
First Year ◽  
Healthy Children ◽  
Nasal Airflow ◽  
Single Session ◽  
Primary Finding ◽  
Patterns Of Behavior ◽  
Cortical Modulation ◽  
First Year Of Life ◽  
Swallowing Apnea

Abstract Research exists that evaluates the mechanics of swallowing respiratory coordination in healthy children and adults as well and individuals with swallowing impairment. The research program summarized in this article represents a systematic examination of swallowing respiratory coordination across the lifespan as a means of behaviorally investigating mechanisms of cortical modulation. Using time-locked recordings of submental surface electromyography, nasal airflow, and thyroid acoustics, three conditions of swallowing were evaluated in 20 adults in a single session and 10 infants in 10 sessions across the first year of life. The three swallowing conditions were selected to represent a continuum of volitional through nonvolitional swallowing control on the basis of a decreasing level of cortical activation. Our primary finding is that, across the lifespan, brainstem control strongly dictates the duration of swallowing apnea and is heavily involved in organizing the integration of swallowing and respiration, even in very early infancy. However, there is evidence that cortical modulation increases across the first 12 months of life to approximate more adult-like patterns of behavior. This modulation influences primarily conditions of volitional swallowing; sleep and naïve swallows appear to not be easily adapted by cortical regulation. Thus, it is attention, not arousal that engages cortical mechanisms.

Gastric electrical activity in normal neonates during the first year of life. Effect of lactation with breast milk and formula

2001 ◽  
Vol 120 (5) ◽  
pp. A209-A209
Author(s):  
G RIEZZO ◽  
R CASTELLANA ◽  
T DEBELLIS ◽  
F LAFORGIA ◽  
F INDRIO ◽  
...  
Keyword(s):  
Breast Milk ◽  
Electrical Activity ◽  
First Year ◽  
Gastric Electrical Activity ◽  
First Year Of Life ◽  
Normal Neonates

Feeding and Function Pleasure in the First Year of Life

2013 ◽  
Author(s):  
Sylvia Brody ◽  
Sidney Axelrad
Keyword(s):  
First Year ◽  
And Function ◽  
First Year Of Life

Predictors of family discipline strategies with babies in their first year of life

2013 ◽  
Author(s):  
Julie Lawrence ◽  
Andrew Gray ◽  
Rachael Taylor ◽  
Barry Taylor
Keyword(s):  
First Year ◽  
First Year Of Life ◽  
Family Discipline
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