Growth in a Population of the Crayfish Pacifastacus leniusculus from a Subalpine Lacustrine Environment

R. Warren Flint

doi:10.1139/f75-280

Growth in a Population of the Crayfish Pacifastacus leniusculus from a Subalpine Lacustrine Environment

Journal of the Fisheries Research Board of Canada ◽

10.1139/f75-280 ◽

1975 ◽

Vol 32 (12) ◽

pp. 2433-2440 ◽

Cited By ~ 18

Author(s):

R. Warren Flint

Keyword(s):

Lake Tahoe ◽

Growing Season ◽

Growth Increment ◽

Pacifastacus Leniusculus ◽

First Year ◽

Size Distributions ◽

Age Classes ◽

Growth Season ◽

Growth Increments ◽

Subalpine Lake

Observations on growth increments at each molt in a population of Pacifastacus leniusculus from a subalpine lake were made from periodically recaptured marked crayfish, as well as from molts recorded in the laboratory. After the first growing season the growth increment at molt remained relatively constant. Throughout the life of this crustacean no differences were observed between sexes. Analysis of size distributions in samples taken at different times of the year revealed that between 8 and 12 year-classes were normally present in the population of Lake Tahoe. Growth of these age-classes could be followed through consecutive samples. The number of molts completed by each year-class was found by relating data on growth increment per molt to growth shown in consecutive quantitative samples. Mean carapace length at recruitment for juvenile crayfish was 3.75 mm with 11 molts occurring during the first growing season, and juveniles reached 13.0 mm by the end of their first year. Molt frequency decreased in successive year-classes, and crayfish surviving past their fourth growth season molted only once a year. Length–weight relationships were similar for both sexes of the population even though their external anatomy differed. Growth comparison between this population and that of a coastal stream population showed that the stream population had a slightly faster overall growth rate due to higher water temperatures and a longer growing season.

Download Full-text

REDUCTION IN GROWTH OF WHITE SPRUCE AFTER OUT-PLANTING

The Forestry Chronicle ◽

10.5558/tfc40488-4 ◽

1964 ◽

Vol 40 (4) ◽

pp. 488-502 ◽

Cited By ~ 8

Author(s):

R. E. Mullin

Keyword(s):

Growing Season ◽

White Spruce ◽

First Year ◽

Age Classes ◽

Nursery Stock ◽

Before And After

Several age-classes of nursery stock were sampled before and after the 1963 growing season by excavation of trees. Samples were also planted out and later excavated. Studies of several criteria to express check were made and leader length selected as the most practicable.It is suggested that, by definition, a tree be considered in check until it has achieved a rate of terminal growth equivalent to that it would have attained in the next season in the nursery. Average leader lengths of unchecked trees are suggested for 2-0, 3-0 and 2-2 stock. Check was found to reduce leader length by about 50% in the first year after outplanting. Other experiments indicate that the effect continued for ten years or more in many instances.

Download Full-text

Effective investments due to seasonal morphological changes? Possible reasons and consequences of allometric growth and reproduction in adult signal crayfish Pacifastacus leniusculus (Dana, 1852).

Canadian Journal of Zoology ◽

10.1139/cjz-2020-0155 ◽

2020 ◽

Author(s):

Miloš Buřič ◽

Phillip Joschka Haubrock ◽

Lukáš Veselý ◽

Pavel Kozak ◽

Antonin Kouba

Keyword(s):

Morphological Changes ◽

Economic Value ◽

Morphological Plasticity ◽

Growing Season ◽

Pacifastacus Leniusculus ◽

Body Parts ◽

Ambient Conditions ◽

Signal Crayfish ◽

Growth Increments ◽

The Family

Signal crayfish Pacifastacus leniusculus (Dana, 1852) are among the most invasive macroinvertebrates in Europe, representing economic value as well as serious threats to ecosystems. Despite decades of research, uncertainties with respect to its biology remain. The present study describes the observations of adult signal crayfish during a single growing season, with a sex ratio of 1:1, reared under natural ambient conditions, in which moulting events, growth-increments, morphological changes, mortality, and reproductive output were monitored. Two moults were observed in the majority of both sexes, with significant differences in moult growth increments of once- and twice-moulted animals. These led to modifications in morphology during the growing season. Females showed isometric growth at the first moult, while, at the second moult, they strengthened the functional state of structures linked to reproduction. In males, the effect was similar, but to a lesser extent, with extensive chelae development at the second moult. There were no differences in relative fecundity of once- and twice-moulted females. However, signal crayfish have different needs during the growing and reproductive season. The presented results indicate the ability to utilize resources according to current needs (development of strategical body parts) via their seasonal morphological plasticity as seen in representatives of the family Cambaridae.

Download Full-text

Size Distributions and Growth of the Fan-shell Pinna bicolor Gmelin (Mollusca : Eulamellibranchia) in South Australia

Marine and Freshwater Research ◽

10.1071/mf9790025 ◽

1979 ◽

Vol 30 (1) ◽

pp. 25 ◽

Cited By ~ 27

Author(s):

AJ Butler ◽

FJ Brewster

Keyword(s):

South Australia ◽

Adductor Muscle ◽

Size Distributions ◽

Limited Data ◽

Length Frequency ◽

Age Classes ◽

Frequency Distributions ◽

Growth And Survival ◽

Random Samples ◽

Variable Success

Fourteen random samples of Pinna bicolor were collected over a period of 31 months from 6 m depth in Gulf St Vincent off Edithburgh, South Australia. The length-frequency distributions suggest that: P. bicolor larvae settle in spring but with variable success; growth of newly settled young is rapid over summer; by age 1 year their modal shell length is about 20 cm; by age 2 it is about 26 cm; they may survive substantially longer than 3 years so that a length-class of mode c. 35 cm is always present and is composed of several age-classes not necessarily equally represented. These suggestions are corroborated by limited data on adductor muscle scars, the development of epibiota on the shells, and the growth and survival of tagged animals over 9 months.

Download Full-text

Size-mediated, density-dependent cannibalism in the signal crayfish Pacifastacus leniusculus (Dana, 1852) (Decapoda, Astacidea), an invasive crayfish in Britain

Crustaceana ◽

10.1163/15685403-00003653 ◽

2017 ◽

Vol 90 (4) ◽

pp. 417-435 ◽

Cited By ~ 6

Author(s):

R. J. Houghton ◽

C. Wood ◽

X. Lambin

Keyword(s):

Relative Size ◽

Pacifastacus Leniusculus ◽

Gut Contents ◽

Size Distributions ◽

Signal Crayfish ◽

Density Dependent ◽

Invasive Crayfish ◽

The Relationship ◽

Best Fit

The role of cannibalism in crayfish populations is not well understood, despite being a potentially key density-dependent process underpinning population dynamics. We studied the incidence of cannibalism in an introduced signal crayfish Pacifastacus leniusculus population in a Scottish lowland river in September 2014. Animals were sampled using six different sampling techniques simultaneously, revealing variable densities and size distributions across the site. Cannibalism prevalence was estimated by analysing the gut contents of crayfish >20 mm CL for the presence of crayfish fragments, which was found to be 20% of dissected individuals. When seeking evidence of relationships between the sizes of cannibals and ‘prey’, the density of conspecifics <56% the size of a dissected individual yielded the best fit. The relationship between cannibalism probability and crayfish size and density was equally well described by three different metrics of crayfish density. Cannibalism increased with crayfish size and density but did not vary according to sex. These results suggest that large P. leniusculus frequently cannibalize smaller (prey) conspecifics, and that the probability of cannibalism is dependent upon the relative size of cannibal-to-prey and the density of the smaller crayfish. We suggest that removing large individuals, as targeted by many traditional removal techniques, may lead to reduced cannibalism and therefore a compensatory increase in juvenile survival.

Download Full-text

PRODUCTIVITY OF PERENNIAL GRASSES AND MIXTURES WITH DIFFERENT SOWING DATES IN WESTERN SIBERIA

Bulletin of NSAU (Novosibirsk State Agrarian University) ◽

10.31677/2072-6724-2020-54-1-24-32 ◽

2020 ◽

pp. 24-32

Author(s):

V. A. Petruk

Keyword(s):

Dry Matter ◽

Crop Yields ◽

Growing Season ◽

Single Species ◽

Field Studies ◽

Perennial Grasses ◽

First Year ◽

Sowing Dates ◽

Second Year ◽

Sowing Period

The results of field studies for 2017 - 2019 are presented. yields of perennial grasses sown at different times of the growing season. Spring, summer, and winter sowing periods were compared. Alfalfa, clover, rump, and also their mixtures were sown in 2017 under the cover of barley. The value of the cover crop yield of spring and summer sowing periods did not differ significantly and amounted to 4-5 t / ha of absolutely dry matter. Winter barley crops have not formed. On average, over 2 years of use, the highest yields were observed in alfalfa-crust grass mixtures - 3.4 t / ha of absolutely dry matter. The lowest yield was obtained in the single-species seeding of the rump. Correspondingly, in the spring, summer and winter periods of sowing, the yield of rump was 1.6; 1.1 and 1.3 t / ha. With a late sowing period, the yield of perennial grasses is significantly lower compared to spring and summer. With winter sowing periods, the yield was the highest for grass stands of alfalfa and alfalfacrust grass mixture - 2.3 and 2.4 t / ha. It should be noted that in the second year of use, the yield by the sowing dates in single-species crops and grass mixtures is leveled. The winter crops of perennial grasses in the first year of use formed a low yield. Only in the second year (third year of life) the productivity of perennial grasses of winter sowing began to increase. Consequently, in the area under perennial grasses of the winter sowing period, during one growing season (the next year after sowing), the crop was not actually formed. Based on the data obtained, production can be recommended for spring and summer planting of perennial grasses under the cover of barley. The winter sowing period provides economically valuable crop yields only by the third year of life.

Download Full-text

Thinlip grey mullet Liza ramada (Mugilidae) caught in a

Fauna norvegica ◽

10.5324/fn.v26i0.571 ◽

2008 ◽

Vol 26 ◽

Author(s):

Bror Jonsson ◽

Nina Jonsson

Keyword(s):

North Sea ◽

Total Mass ◽

First Year ◽

English Channel ◽

Grey Mullet ◽

Font Size ◽

Growth Season ◽

The North ◽

The North Sea ◽

First Year Of Life

Two individuals of thinlip grey mullet Liza ramada were collected in a southern Norwegian brook (58° 22’ N, 8° 37’ E) on 12th September 2007. The fish were 8.7 and 9.0 cm in total length, 6 and 7 g in total mass, and most probably in their first year of life. The nearest known spawning area of the species is south of the English Channel, meaning that they had probably moved at least 900 km across the North Sea during their first growth season. To our knowledge, this is the first published observation of the catadromous thinlip grey mullet from a Scandinavian freshwater course.

Download Full-text

Further Analysis of Ration and Growth Relationship of Plaice (Pleuronectes platessa)

Journal of the Fisheries Research Board of Canada ◽

10.1139/f69-305 ◽

1969 ◽

Vol 26 (12) ◽

pp. 3237-3241 ◽

Cited By ~ 2

Author(s):

Samir Zaky Rafail

Keyword(s):

Maximum Growth ◽

Growth Efficiency ◽

Growth Increment ◽

Mean Value ◽

Pleuronectes Platessa ◽

Growth Increments ◽

Power Equation ◽

The Mean ◽

Relationship Of ◽

Weight Groups

Evidence is given that the average daily rations (R) and fortnightly growth increments (ΔW) of six weight groups of Pleuronectes platessa fed on Mytilus edulis are related as in the power equation ±(ΔW−ΔWm) = ±b(|R–Rm|)B. Rm is the daily ration associated with the growth increment (ΔWm) at maximum growth efficiency; b and B are parameters. The power B has a mean value of about 0.5 and shows significant deviations from the mean especially in the case of smaller fish.

Download Full-text

Patterns and predictors of food texture introduction in French children aged 4–36 months

British Journal Of Nutrition ◽

10.1017/s0007114518002386 ◽

2018 ◽

Vol 120 (9) ◽

pp. 1065-1077 ◽

Cited By ~ 9

Author(s):

Lauriane Demonteil ◽

Eléa Ksiazek ◽

Agnès Marduel ◽

Marion Dusoulier ◽

Hugo Weenen ◽

...

Keyword(s):

Complementary Feeding ◽

Eating Habits ◽

First Year ◽

Age Classes ◽

Cross Sectional Survey ◽

Cross Sectional ◽

Food Texture ◽

Second Year ◽

Almost All ◽

Linear Regressions

AbstractThe aims of this study were to describe which and when food textures are offered to children between 4 and 36 months in France and to identify the associated factors. An online cross-sectional survey was designed, including questions about 188 food texture combinations representing three texture levels: purées (T1), soft small pieces (T2) and hard/large pieces and double textures (T3). Mothers indicated which combinations they already offered to their child. A food texture exposure score (TextExp) was calculated for all of the texture levels combined and for each texture level separately. Associations between TextExp and maternal and child characteristics and feeding practices were explored by multiple linear regressions, per age class. Answers from 2999 mothers living in France, mostly educated and primiparous, were analysed. Over the first year, children were mainly exposed to purées. Soft and small pieces were slowly introduced between 6 and 22 months, whereas hard/large pieces were mainly introduced from 13 months onwards. TextExp was positively associated with children’s number of teeth and ability to eat alone with their finger or a fork. For almost all age classes, TextExp was higher in children introduced to complementary feeding earlier, lower for children who were offered only commercial baby foods and higher for those who were offered only home-made/non-specific foods during the second year. Our study shows that until 12 months of age the majority of French children were exposed to pieces to a small extent. It provides new insights to further understand the development of texture acceptance during a key period for the development of eating habits.

Download Full-text

Effects of cutting and cold-storage of parent canes on cane production of raspberry

Australian Journal of Experimental Agriculture ◽

10.1071/ea9860501 ◽

1986 ◽

Vol 26 (4) ◽

pp. 501

Author(s):

BM El-Zeftawi ◽

FH Goubran ◽

JG Richards

Keyword(s):

Cold Storage ◽

Plant Material ◽

Growing Season ◽

First Year ◽

June July

Parent canes of Willamette raspberry produced more vigorous canes than those of Glen Clova although the latter was less prone to bud failure in the first year. Reducing the length of the parent canes encouraged cane production and lowered the incidence of bud failure. Freshly dug plant material had more canes and less bud failure than those stored at 2�C, particularly when planted during June-July. For all treatments, the percentage of fruiting canes was 2-3 times higher in the second growing season than in the first, despite the total number of canes being less.

Download Full-text

Growth Increments and Geochemical Variations in the Molluscan Shell

Notes for a Short Course: Studies in Geology ◽

10.1017/s027116480000110x ◽

1985 ◽

Vol 13 ◽

pp. 72-87 ◽

Cited By ~ 1

Author(s):

Douglas S. Jones

Keyword(s):

Shell Growth ◽

Maximum Growth ◽

Growth Increment ◽

Growth Patterns ◽

Random Disturbance ◽

Growth Increments ◽

Molluscan Shell ◽

External Shell ◽

Periodic Growth ◽

Geochemical Variations

Perhaps the one structural feature of the molluscan shell which has historically attracted the most attention from biologists and paleobiologists alike is the banding or growth increment variation associated with so many molluscan species. Such growth patterns are often prominently displayed on the external surfaces of shells and have long been the focus of serious biological and paleontological research (see reviews by Clark, 1974; Lutz and Rhoads, 1980). The usefulness of external shell growth patterns in ecological or paleoecological contexts is limited, however, by both the inability to distinguish true periodic features from random disturbance marks and by the extreme crowding of growth lines near the margins of mature shells. In the last two decades these problems have been surmounted with the recognition of periodic growth patterns within molluscan shells. Internal shell growth patterns are known from all classes of mollusks, but those in the Bivalvia have been studied most extensively. This is a result of the relative ease with which a complete ontogenetic growth record can be obtained by sectioning a shell along the axis of maximum growth (Rhoads and Pannella, 1970). Analogous ontogenetic records are very difficult, if not impossible, to obtain from coiled or spiral shells (e.g., gastropods) using current techniques (Lutz and Rhoads, 1980). This chapter, then, aims to review the major types of internal shell growth patterns described within molluscan shells (mainly bivalves) and to discuss their origin and applications in ecology and paleoecology. Also taken up in this chapter is a brief consideration of geochemical variations (stable oxygen and carbon isotopes and trace and minor elements) within molluscan shells. Physical-chemical, environmental, and physiological influences on shell chemistry are discussed in relation to how biogeochemical variations in the shell may be used to reconstruct paleoenvironmental conditions.

Download Full-text