Life spans of two species of tropical mayfly nymph (Ephemeroptera) from Magela Creek, Northern Territory

1982 ◽  
Vol 33 (1) ◽  
pp. 173 ◽  
Author(s):  
R Marchant
Keyword(s):  
Life Cycle ◽  
Life Span ◽  
Northern Territory ◽  
Annual Production ◽  
Length Frequency ◽  
Frequency Method ◽  
B Values ◽  
Size Frequency ◽  
Mayfly Nymph ◽  
Growth And Reproduction

The nymphs of Cloeon fuviatile and a species of Tasmanocoenis were common in the shallows (< 1 m) of two billabongs in Magela Creek, Northern Territory. Monthly estimates of abundance and length frequency showed that growth and reproduction occurred continuously. Estimates of the ratio of annual production to mean biomass (PIB) were calculated with the size-frequency method, using different values for nymphal life span; these estimates, when compared with P/B values predicted from the literature, suggested that the nymphs had a life span of about 1 month. Such a rapid life cycle is at least in part the result of the high mean temperature (30°C) in the shallows.

Life history, secondary production and population dynamics of Gammarus fossarum (Koch, 1836) in a constant temperature stream

Biologia ◽  
2012 ◽  
Vol 67 (1) ◽  
Author(s):  
Pavel Beracko ◽  
Anna Sýkorová ◽  
Andrej Štangler
Keyword(s):  
Life Cycle ◽  
Constant Temperature ◽  
Growth Function ◽  
Dry Mass ◽  
Frequency Method ◽  
Daily Growth ◽  
Gammarus Fossarum ◽  
Frequency Distributions ◽  
Size Frequency ◽  
The Mean

AbstractPopulation of the freshwater amphipod Gammarus fossarum was investigated in a calcareous stream with almost constant temperature (7–8°C) in the Chočské Vrchy Mts (West Carpathians, Slovakia). Quantitative samples of G. fossarum taken during 2005 showed population densities varying from 100 m−2 in August to 585 m−2 in late November. The population was split into juveniles, mature males, mature females without eggs and females with eggs. The percentage of juveniles (40–64%) was always the highest of any of the categories. Ovigerous females occurred throughout the year. The mean sex ratio was 1: 2.4 (male: female), although its values varied considerably with the time of year. Breeding was continuous, although juvenile recruitment peaked in early spring, summer and early winter. Three discrete cohorts were distinguished from the size frequency distributions. The life span was 6–7 months and the individuals matured approximately in the half of life cycle. The mean fecundity was 9.6 embryos per brood. Variation in fecundity was mostly explained by size of the incubating females. The absolute growth of this species was best described by the Gompertz growth function. Relative growth rates (% body DM day−1) fluctuated in a nonlinear manner with size and age. The highest values of daily growth (2–4% of dry mass per day) were noted approximately in the half of life cycle. Annual production, estimated by the size-frequency method, was 1618.9 g dry mass m−2 and P/B ratio was 5.15.

Estimates of annual production for some aquatic insects from the La Trobe River, Victoria

1986 ◽  
Vol 37 (2) ◽  
pp. 113 ◽  
Author(s):  
R Marchant
Keyword(s):  
Aquatic Insects ◽  
Temperate Zone ◽  
Annual Production ◽  
Frequency Method ◽  
Habitat Temperature ◽  
Size Frequency ◽  
Total Annual Production ◽  
Annual Turnover

Annual production was estimated by the size-frequency method for Ephemeroptera (Tasmanocoenis tonnoiri, two species of Baetis, Atalonella spp., Atulophlebioides sp.), Plecoptera (Leptoperla spp.) and Trichoptera (Ecnomus sp.) at four sites on the lowland section of the La Trobe River. Annual production (P) of individual ephemeropteran species (or genera) varied from 0.02 to 0.7 g m-2 while total annual production of this order at two sites was 0.7-1 . 5 g m-. Annual production of Leptoperla spp. was 0.03 g m-2 at one site while Ecnomus sp, averaged 2 g m-2 at two sites. Estimates of annual production were subject to an error of at least t 50%. Annual turnover ratios (P/B; B is mean biomass) varied from 9 to 19 and were three to four times higher than published values for similar-sized macroinvertebrates in the temperate zone (generally < 15°C mean annual habitat temperature). This probably resulted from the higher average temperatures (17-18°C) at most sites.

Production of the amphipod Hyalella azteca (Saussure) in a northern Ontario lake

1983 ◽  
Vol 61 (9) ◽  
pp. 2051-2059 ◽  
Author(s):  
Dorothy H. Lindeman ◽  
Walter T. Momot
Keyword(s):  
Littoral Zone ◽  
Lake Ontario ◽  
Hyalella Azteca ◽  
Dry Weight ◽  
Annual Production ◽  
Frequency Method ◽  
Northern Ontario ◽  
Habitat Temperature ◽  
Size Frequency ◽  
Annual Biomass

Annual production of the amphipod, Hyalella azteca, was estimated in three habitats of the upper littoral zone of Dock Lake, Ontario, over a 2-year period (1980–1981). Cohort production (P) by the size frequency method was 1.39 g/m2 (dry weight), mean annual biomass (B) was 0.36 g/m2, and the P/B ratio was 3.9 for the 1980 year class. Five other methods for estimating production were applied to this cohort, providing comparable estimates ranging from 1.21 (instantaneous growth) to 1.65 (cohort G) g/m2. Size frequency estimates of annual production for 1980 and 1981 were 1.24 and 1.40 g/m2, respectively. The annual P/[Formula: see text] ratios of 3.9 and 4.0 for these 2 years agree with the cohort value. A comparison of production estimates for Hyalella azteca in the literature shows a gradient of production which correlates with the habitat temperature regime.

Population and Production Dynamics of an Enchytraeid Worm in a Subtropical Blackwater River

1987 ◽  
Vol 44 (8) ◽  
pp. 1469-1474 ◽  
Author(s):  
David L. Stites
Keyword(s):  
Aquatic Insect ◽  
Dry Mass ◽  
Coarse Sand ◽  
Annual Production ◽  
Total Density ◽  
Frequency Method ◽  
Blackwater River ◽  
Size Frequency ◽  
Center Channel ◽  
Production Dynamics

Population and production dynamics of Barbidrilus paucisetus Loden and Locy (Oligochaeta: Enchytraeidae) in a sixth-order blackwater river are described. This worm was the dominant member of the meiofauna of the sand habitat, accounting for 50–90% of the total density. Population density varied seasonally, increasing from < 20 000/m2 in the winter to 60–120 000/m2 in the summer. Biomass averaged 145 mg dry mass/m2 with a range of 8–326 mg/m2. Density peaked in the clean coarse sand of the center channel areas and was lower where the sand was finer and where more organic matter was present. Size frequency histograms indicated that there were three recruitment peaks during the sampling year, with mature and new individuals present in all seasons. Annual production (2.12 g dry mass/m2, SE = 0.15 g/m2), was estimated using the size frequency method and a cohort production interval correction of 3. Annual production was low compared with that of terrestrial Enchytraeidae and comparable with that of many aquatic insect species. Annual production/biomass ratio (14.3) was higher than terrestrial Enchytraeidae, due to the comparatively short generation time of this species.

Use of the Size–Frequency (Hynes) Method to Estimate Annual Production of a Stream Fish Population

1983 ◽  
Vol 40 (11) ◽  
pp. 2030-2034 ◽  
Author(s):  
Greg C. Garman ◽  
Thomas F. Waters
Keyword(s):  
Salmo Trutta ◽  
Fish Population ◽  
Annual Production ◽  
Salmo Gairdneri ◽  
Frequency Method ◽  
Reliable Determination ◽  
Size Frequency ◽  
Production Values ◽  
Significant Difference

Previously developed and accepted methods of fish production estimation, such as instantaneous growth (G method), require aging of sampled individuals. Hynes' size–frequency method, however, does not require cohort separation. Annual production and approximate 95% confidence intervals are presented and compared for populations of brook, brown, and rainbow trout (Salvelinus fontinalis, Salmo trutta, and Salmo gairdneri) in Valley Creek, Minnesota, 1977–78, using the size–frequency and G methods. No significant difference was found between production values calculated by the two methods. It is proposed that the size–frequency method provides a reliable determination of annual production of fish populations and will be especially useful where accurate aging of individuals is not possible or where aging represents excessive labor.

Annual Production by Caddisflies and Mayflies in a Western Minnesota Plains Stream

1982 ◽  
Vol 39 (12) ◽  
pp. 1628-1635 ◽  
Author(s):  
M. B. MacFarlane ◽  
T. F. Waters
Keyword(s):  
Standing Stock ◽  
Annual Production ◽  
Insect Community ◽  
Downstream Site ◽  
Frequency Method ◽  
Third Order ◽  
Upstream Site ◽  
Size Frequency ◽  
Total Annual Production ◽  
Wet Weight

Annual production was estimated for five species of caddisflies and mayflies, comprising major components of the insect community, in the Redwood River, a second- to third-order plains stream in western Minnesota. Estmates were made at two sites, one above and one below an impoundment. At the upstream site, annual production (g∙m−2, wet weight) and annual P/B ratios (in parentheses) were Hydropsyche bifida, 8.3 (6.9); Cheumatopsyche pettiti, 5.5 (7.0); Stenonema nepotellum, 3.4 (5.7); Stenacron interpunctatum canadense, 0.8 (7.0); and Caenis simulans, 4.7 (4.2); with total annual production of 22.7 g∙m−2. At the downstream site, annual production and P/B ratios were H. bifida, 34.3 (4.4); C. pettiti, 68.5 (4.4); S. interpunctatum canadense, 24.1 (6.1); and C. simulans, 2.8 (4.4); with total annual production of 129.7 g∙m−2. These species comprised 27.5% of the total insect standing stock at the upstream site and 75.9% downstream. The hydropsychid production at the downstream site was apparently sustained by the drift of zooplankton from the impoundment, resulting in considerably higher production by hydropsychids than reported in woodland streams.Key words: production, Trichoptera, Ephemeroptera, plains stream, benthos, size–frequency method

Effects of Long-Term Exposure to Carbaryl (Sevin) on Survival, Growth, and Reproduction of the Fathead Minnow (Pimephales promelas)

1972 ◽  
Vol 29 (5) ◽  
pp. 583-587 ◽  
Author(s):  
A. R. Carlson
Keyword(s):  
Life Cycle ◽  
Fathead Minnow ◽  
Pimephales Promelas ◽  
Threshold Concentration ◽  
Fathead Minnows ◽  
Motile Sperm ◽  
High Concentration ◽  
Toxicant Concentration ◽  
Growth And Reproduction

When fathead minnows (Pimephales promelas) were exposed to five concentrations (0.008–0.68 mg/liter) of the insecticide carbaryl for 9 months and throughout a life cycle, the highest concentration prevented reproduction and decreased survival. At the high concentration, testes contained motile sperm and ovaries were in a flaccid condition and appeared to be in a resorptive state. At the 0.68 mg/liter concentration, carbaryl appeared to contribute to mortality of larvae (produced by unexposed parents) within 30 days of hatching. Survival of young grown in the 0.008 mg/liter concentration was reduced. Since no demonstrable effects were noted for survival, growth, or reproduction at the 0.017, 0.062, and 0.21 mg/liter concentrations, this low survival value is considered not due to carbaryl. The 96-hr median tolerance concentration (TL 50) and the lethal threshold concentration (LTC) for 2-month-old fathead minnows were 9.0 mg/liter. The maximum acceptable toxicant concentration (MATC) for fathead minnows exposed to carbaryl in water with a hardness of 45.2 mg/liter and a pH of 7.5 lies between 0.21 and 0.68 mg/liter. The application factors (MATC/96-hr TL50 and MATC/LTC) both lie between 0.023 and 0.075.

Some Uses of Probability Paper in the Analysis of Size Frequency Distributions

1954 ◽  
Vol 5 (3) ◽  
pp. 513 ◽  
Author(s):  
RM Cassie
Keyword(s):  
Frequency Analysis ◽  
Length Frequency ◽  
Scale Reading ◽  
Frequency Distributions ◽  
Probability Paper ◽  
Size Frequency ◽  
Graph Paper ◽  
Probability Graph ◽  
Age Determinations ◽  
Length Frequency Analysis

Methods are described by which the component groups may be extracted from polymodal size frequency samples by the use of probability graph paper. Four examples are given illustrating: the solution of a distribution with more than two modes and with only one exposed flank; the coordination of fish age determinations by the two methods, length frequency analysis and scale reading; a bivariate sample where the two means coincide though the standard deviations are different; a method of correcting for truncation.

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