scholarly journals Seasonal changes in population and age composition of the roof rat, Rattus rattus Linnaeus in a building

1994 ◽  
Vol 45 (3) ◽  
pp. 293-295
Author(s):  
Tsutomu TANIKAWA
Keyword(s):  
Seasonal Changes ◽  
Rattus Rattus ◽  
Age Composition

Seasonal Changes in Population Density and Vertical Distribution of prosobranch veligers in offshore Plankton at Plymouth

1973 ◽  
Vol 53 (3) ◽  
pp. 471-492 ◽  
Author(s):  
Vera Fretter ◽  
D. Shale
Keyword(s):  
Population Density ◽  
Vertical Distribution ◽  
Seasonal Changes ◽  
Littorina Littorea ◽  
Ageing Population ◽  
Age Composition ◽  
Number Of Species ◽  
Lacuna Vincta ◽  
Nassarius Reticulatus ◽  
Inshore Waters

Vertical and horizontal hauls were taken at approximately fortnightly intervals from April 1969 to April 1970 at L 3 (lat. 40° 17.7′ N, long. 4° 11.2′ W) and L 4 (lat. 50° 15′ N, long. 4° 12.5 W). Thirty-two species of prosobranch veliger were present at L 35 these larvae were not as numerous at L 4 and only 26 species were recorded. The number of species was highest in the summer: the number of veligers was highest in February. After mid October both the number of species and the abundance of veligers decreased rapidly and remained low until early February. Veligers of some species occurred later at L 3 and L 4 than in more inshore waters and these were probably individuals carried beyond tidal influences which would normally lead to settlement on the shore. They included Lacuna vincta, Littorina littorea and L. neritoides.Veligers of all ages were found at all depths. At their time of greatest abundance veligers of many species occurred maximally at 5 or 10 m, with a variable decrease towards greater depths and a sudden one towards the surface. This distribution later changed giving a proportionally greater number at greater depth. When numbers were low the larvae scattered through the water column with little or no indication of a preferred depth. An examination of the age composition of veligers of rissoids, Natica alderi, Nassarius reticulatus and Philbertia linearis from certain catches showed that the surface accumulation at the time of abundance was composed of a high percentage of young veligers: in an ageing population there was a higher percentage of larvae, especially the older ones, at greater depths, except for Nassarius reticulatus which consistently showed maximal numbers above 10 m until the larvae became scarce.

scholarly journals SEASONAL CHANGES IN THE IMAGO PHYSIOLOGICAL AGE IN THE DERMACENTOR MARGINATUS (ACARI, IXODIDAE) NATURAL POPULATION IN THE CENTRAL CISCAUCASIA

2021 ◽  
pp. 3-8
Author(s):  
E.V. Lazarenko ◽  
◽  
L.I. Shaposhnikova ◽  
N.V. Yermolova ◽  
◽  
...  
Keyword(s):  
Seasonal Changes ◽  
Natural Populations ◽  
Physiological Age ◽  
Observation Site ◽  
Age Composition ◽  
Dermacentor Marginatus ◽  
The Third ◽  
Entire Observation Period ◽  
Ixodes Ticks ◽  
Observation Period

The article discusses the seasonal changes in the age composition (physiological age) of imagoes of Dermacentor marginatus ticks natural populations. To determine the physiological age, we used 1477 hungry imagoes of D. marginatus, collected on a flannel flag, under the conditions of a stationary observation site. During the entire observation period, ticks of the third physiological age prevailed. Wintering imagoes include ticks of third and fourth physiological ages. In April, at the peak of activity, the nucleus of the population is made up of ticks of second and third physiological age. A small part of the population during this period is made up of individuals of fourth physiological age. In May, the percentage of recently activated individuals decreases markedly. In collections of this period, strongly emaciated individuals of fourth physiological age predominate. The summer population of ticks is represented by individuals of the third and fourth physiological ages. Their share is over 90%. Individuals of second physiological age were found by us only in early June and late August. In autumn, the bulk of the population is also represented by individuals of third and fourth physiological ages. Keywords: imagoes, Ixodes ticks, Dermacentor marginatus, Central Ciscaucasia, physiological age, age composition

Lake Use by Wild Anadromous Atlantic Salmon, Salmo salar, as an Index of Subsequent Adult Abundance

1986 ◽  
Vol 43 (1) ◽  
pp. 2-11 ◽  
Author(s):  
P. M. Ryan
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Seasonal Changes ◽  
Catch Per Unit Effort ◽  
Age Composition ◽  
Atlantic Salmon Salmo Salar ◽  
Spawning Areas ◽  
Population Sizes ◽  
Standing Waters ◽  
Adult Abundance

Atlantic salmon, Salmo salar, were censused each spring and fall for 5 or 6 yr in two lakes at the headwaters of the Gander River, Newfoundland. Density, biomass, and age varied seasonally and annually, ranging from 5.2 to 78.7 fish∙ha−1, 0.2 to 3.4 kg∙ha−1, and 1 to 7 yr, respectively. Seasonal changes in age composition were used to calculate net numbers and ages of fish moving into and out of the lakes. Population sizes typically increased from fall to spring as young fish moved into the lakes from downstream spawning areas and decreased from spring to fall as older fish moved downstream. The calculated net number of spring to fall emigrants over 6 yr was positively correlated (r = 0.835) with adult abundance (catch per unit effort) in the recreational fishery 1 yr later. The varying modal age of these emigrants was identical to the modal freshwater age of returning adults in each of four comparable years. Censusing of young Atlantic salmon in standing waters can be used to monitor smolt production and assist in prediction of the subsequent abundance of sea-run adults.

Spreading the Word: Seasonal Changes Mean New Opportunities for Media Coverage

ASHA Leader ◽  
2013 ◽  
Vol 18 (7) ◽  
Keyword(s):  
Media Coverage ◽  
Seasonal Changes ◽  
Swimming Pools

Summer kicking into high gear conjures images of swimming pools and barbeques. But before you book your beach house for the weekend, think about what the changing seasons can mean for you professionally.

Seasonal changes in a ultraviolet structural colour signal in blue tits, Parus caeruleus

2002 ◽  
Vol 76 (2) ◽  
pp. 237-245 ◽  
Author(s):  
JONAS ORNBORG ◽  
STAFFAN ANDERSSON ◽  
SIMON C. GRIFFITH ◽  
BEN C. SHELDON
Keyword(s):  
Seasonal Changes ◽  
Parus Caeruleus ◽  
Structural Colour ◽  
Blue Tits ◽  
Colour Signal

Seasonal changes in nitrogen fractions of Pachysandra terminalis, a forest evergreen chamaephyte

1990 ◽  
Vol 79 (1) ◽  
pp. 7-14 ◽  
Author(s):  
Fumio Yoshie ◽  
Hirohito Arai ◽  
Hideaki Nakashima ◽  
Shoichi Kawano
Keyword(s):  
Seasonal Changes ◽  
Nitrogen Fractions

MODULATION OF TRIGLYCERIDES IN FEMALE RATTUS RATTUS WITH STEROID CONTRACEPTIVE ALGESTONE ACETOPHENIDE (DHPA)

2019 ◽  
Vol 25 (1) ◽  
Author(s):  
ASHOK KUMAR ◽  
ALPANA PARMAR ◽  
ANAND KUMAR BAJPEYEE
Keyword(s):  
Mixed Type ◽  
Rattus Rattus ◽  
Young Female ◽  
Female Rats ◽  
Control Group ◽  
Black Rat ◽  
Long Acting ◽  
Steroid Contraceptive

Young female Black rat (Rattus rattus), were administered monthly long acting steroid contraceptive to induce hypertriglyceridemia. It was observed that by 3 weeks of the second injection of estrogen containing mixed type of contraceptive, female rats developed consistent and frank hyperglyceridemia . TG in the treated rats was 195.8 ± 7.44 mg /100 ml as compared to 91.5 ± 6.27 mg/100ml in plasma of the control group.

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