Cycle de développement, croissance, effectifs, biomasse et production de Bithynia tentaculata L. (Gastropoda : Prosobranchia) dans le Saint-Laurent (Québec)

1981 ◽  
Vol 59 (7) ◽  
pp. 1237-1250 ◽  
Author(s):  
B. Vincent ◽  
G. Vaillancourt ◽  
M. Harvey
Keyword(s):  
Life Cycle ◽  
North America ◽  
Reproductive Strategy ◽  
Sexual Maturity ◽  
Individual Growth ◽  
Bithynia Tentaculata ◽  
St Lawrence River

The life cycle of Bythinia tentaculata has been studied over a period of 2 years in five localities of the freshwater estuary of the St. Lawrence River. Sexual maturity is attained after 2 years and the species is iteroparous; this might prove to be a particularly advantageous reproductive strategy in this river. The main phases of individual growth are related to age and thermal variations of the water and they occur during the months of May, June, and July of the first 2 years. Eggs are laid once a year and growth stops during winter for about 6 months. These results on the life cycle and growth of B. tentaculata, particularly in the fluvial section of the St. Lawrence River, are more similar to those obtained in Europe than to those obtained elsewhere in North America. Numbers, biomass, and production are markedly higher here than the values found by other investigators on the same species.[Journal translation]

Cycle de développement, croissance et production de Pisidium amnicum (Mollusca: Bivalvia) dans le Saint-Laurent (Québec)

1981 ◽  
Vol 59 (12) ◽  
pp. 2350-2359 ◽  
Author(s):  
B. Vincent ◽  
G. Vaillancourt ◽  
N. Lafontaine
Keyword(s):  
Population Dynamics ◽  
Sexual Maturity ◽  
Dry Weight ◽  
Mortality Rates ◽  
The Other ◽  
Annual Production ◽  
Bithynia Tentaculata ◽  
The Mean ◽  
Total Dry Weight ◽  
St Lawrence River

The population dynamics of Pisidium amnicum have been studied in one population of the St. Lawrence River over a 2-year period during which 19 samples were taken. The species can live up to 3 years and it is iteroparous; individuals generally attain sexual maturity after 1 year and they reproduce twice, once at 2 and once at 3 years of age. In adults, mortality is lower in winter than during the rest of the year and mortality rates are twice as high during the 1st year than during the 2nd year. Total dry weight (PT, in milligrams) is related to maximum length (L, in millimetres) according to the equation PT = 0.0283∙L3,80 and flesh dry weight (PC, in milligrams) is related to length as follows: PC = 0.007∙L3,18. The annual production to mean biomass (P/B) ratio is 1.4, the mean annual production being 1.298 mg/m2 of total dry weight and 107 mg/m2 of flesh weight. Comparing these results with those obtained for the gastropod Bithynia tentaculata in the same environment and at the same period of the year has shown that the growth of Pisidium amnicum is far less influenced by the temperature regime than that of the other species and that its production is at least 10 times lower.

scholarly journals Biologie et situation de la Lamproie du Nord, Ichthyomyzon fossor, au Québec

2007 ◽  
Vol 121 (4) ◽  
pp. 402 ◽  
Author(s):  
Christian Fortin ◽  
Martin Ouellet ◽  
Isabelle Cartier ◽  
Daniel Banville ◽  
Claude B. Renaud
Keyword(s):  
Water Pollution ◽  
Life Cycle ◽  
North America ◽  
Fresh Water ◽  
Habitat Degradation ◽  
Adult Size ◽  
Brook Lamprey ◽  
Streams And Rivers ◽  
Dispersal Abilities ◽  
St Lawrence River

La Lamproie du Nord est une espèce propre à l’Amérique du Nord et elle ne se rencontre, au Québec, que dans l’extrême sud de la province. Cette lamproie a été observée dans le fleuve Saint-Laurent ainsi que dans 11 de ses tributaires. Elle aurait disparu de la rivière Yamaska où elle avait été recensée entre 1946 et 1959. Poisson non parasite, sa taille au stade adulte ne dépasse habituellement pas 160 mm. Les larves, appelées ammocètes, et les adultes ne se retrouvent qu’en eau douce. Les cours d’eau utilisés sont généralement des ruisseaux et des rivières à fond graveleux ou sablonneux. La Lamproie du Nord requiert deux habitats distincts, soit un pour les adultes reproducteurs et un autre, le long du même cours d’eau, pour le développement des ammocètes. La détérioration de l’habitat et la pollution des eaux représentent les principales menaces à la survie des lamproies. La faible fécondité et la mobilité réduite de la Lamproie du Nord font en sorte que cette espèce est peu adaptable aux modifications de son environnement.The Northern Brook Lamprey is endemic to North America. In Quebec, it is restricted to the southernmost part of the province. This lamprey is known from the St. Lawrence River as well as in 11 of its tributaries. It appears to have been extirpated from the Yamaska River where it was collected between 1946 and 1959. It is a nonparasitic fish and its adult size does not usually exceed 160 mm. Larvae, called ammocoetes, and adults are found only in fresh water. Watercourses where it occurs are generally streams and rivers with gravel or sandy bottoms. The Northern Brook Lamprey requires two types of habitats during its life cycle, one for spawning adults and one, along the same watercourse, for the developing ammocoete. Habitat degradation and water pollution are the major threats to the survival of lampreys. The low fecundity and low dispersal abilities of the Northern Brook Lamprey make this species poorly adapted to withstand changes in its environment.

Variations inter-populations de la structure d'âge et de la croissance du Prosobranche Bithynia tentaculata L.

1985 ◽  
Vol 63 (6) ◽  
pp. 1345-1353 ◽  
Author(s):  
B. Vincent ◽  
C. Létourneau
Keyword(s):  
Age Structure ◽  
Sexual Maturity ◽  
Abiotic Factors ◽  
Temporal Variations ◽  
Population Densities ◽  
Bithynia Tentaculata ◽  
Spatio Temporal ◽  
Sudden Decrease ◽  
Velocity Water ◽  
St Lawrence River

The main variations in age structure and growth of different generations were studied in 25 populations of the prosobranch Bithynia tentaculata in the St. Lawrence River (Québec). The general unbalanced age structures of the populations reflect a low recruitment encountered during an odd year because of a general disturbance in the environment. The age structure is correlated to temperature, sediments, and current velocity. Water chemistry is largely responsible for the spatial variations in lengths of the adults, but these variations do not seem to influence the age at sexual maturity. Population densities may be regulated by an increase in the growth rate of young which would reduce the age at sexual maturity in populations with low densities; this mechanism would, however, be of little use to compensate a sudden decrease in density or an unbalanced age structure in a population. These results and those of previous studies on this species reveal the important role played by abiotic factors in regulating the spatio-temporal variations of the demographic profile of this prosobranch which possesses a high phenotypic plasticity.[Journal translation]

Variations de la fécondité et de la structure des populations chez Bithynia tentaculata L. (Gastropoda: Prosobranchia)

1983 ◽  
Vol 61 (11) ◽  
pp. 2417-2423 ◽  
Author(s):  
B. Vincent ◽  
M. Gaucher
Keyword(s):  
Growth Rate ◽  
Population Structure ◽  
Sexual Maturity ◽  
Temporal Variations ◽  
Bithynia Tentaculata ◽  
Poor Recruitment ◽  
One Year ◽  
Iteroparous Species ◽  
St Lawrence River

In 1982, we studied three populations of the snail Bithynia tentaculata living in a cold environment in the upper estuary of the St. Lawrence River (Quebec), with particular emphasis on the population structure and the fecundity of the different generations. This and other studies show that large variations can occur in the age of sexual maturity from year to year; these are caused by variations in the growth rate and could cause important changes in the growth rate of the populations. Also, there does not appear to be an adequate mechanism to compensate poor recruitment in one year and thus an unbalance in the population structure can be seen for at least 7 years. Fecundity varies from one population to another and from one year to the next. Differences are greater between populations, but both phenomena often interact. These results show the relevance of long-term observations, still quite rare, in order to interpret spatial and temporal variations in the bionomics of iteroparous species.[Journal translation]

Rites of Passage

2018 ◽  
Author(s):  
Axel Michaels
Keyword(s):  
Life Cycle ◽  
Old Age ◽  
Sexual Maturity ◽  
Rites Of Passage ◽  
Life And Death ◽  
Transformational Process ◽  
Local Contexts ◽  
Vulnerable Community ◽  
History Of ◽  
The Individual

This chapter examines the classical Hindu life-cycle rites, the term saṃskāra and its history, and the main sources (Gṛhyasūtras and Dharma texts). It presents a history of the traditional saṃskāras and variants in local contexts, especially in Nepal. It describes prenatal, birth and childhood, initiation, marriage, old-age, death, and ancestor rituals. Finally, it analyzes the transformational process of these life-cycle rituals in the light of general theories on rites of passage. It proposes, in saṃskāras, man equates himself with the unchangeable and thus seems to counteract the uncertainty of the future, of life and death, since persons are confronted with their finite existence. For evidently every change, whether social or biological, represents a danger for the cohesion of the vulnerable community of the individual and society. These rituals then become an attempt of relegating the effects of nature or of mortality: birth, teething, sexual maturity, reproduction, and dying.

Early Maize in Northeastern North America: A Comment on Emerson and Colleagues

2021 ◽  
Vol 86 (2) ◽  
pp. 425-427
Author(s):  
John P. Hart ◽  
William A. Lovis ◽  
M. Anne Katzenberg
Keyword(s):  
North America ◽  
Great Lakes ◽  
Empirical Evidence ◽  
River Valley ◽  
Human Bone ◽  
Northeastern North America ◽  
Isotopic Evidence ◽  
St Lawrence River

Emerson and colleagues (2020) provide new isotopic evidence on directly dated human bone from the Greater Cahokia region. They conclude that maize was not adopted in the region prior to AD 900. Placing this result within the larger context of maize histories in northeastern North America, they suggest that evidence from the lower Great Lakes and St. Lawrence River valley for earlier maize is “enigmatic” and “perplexing.” Here, we review that evidence, accumulated over the course of several decades, and question why Emerson and colleagues felt the need to offer opinions on that evidence without providing any new contradictory empirical evidence for the region.

Life cycle of the western school prawn, Metapenaeus dalli Racek, in a Western Australian estuary

1986 ◽  
Vol 37 (1) ◽  
pp. 95 ◽  
Author(s):  
IC Potter ◽  
JW Penn ◽  
KS Brooker
Keyword(s):  
Life Cycle ◽  
Western Australia ◽  
Sexual Maturity ◽  
Second Year Of Life ◽  
Second Year ◽  
Australian Estuary ◽  
Western Australian

The absence of marine records for M. dalli below latitude 31�S., together with data on gonadal stages and spermatophore deposition on females of this species in the Swan estuary, provide very strong indications that the western school prawn typically breeds in estuarine environments in south-western Australia. The 0 + recruits, which first appeared in samples in February, remained in the estuary during the following months and by November had reached a size suitable for exploitation. At this time they were approaching sexual maturity and were starting to move from the shallows to the deeper waters of the estuary where they remained for their second year of life. In contrast to Australian Penaeus species, M. dalli mates during the intermoult period when the shell is hard rather than immediately after moulting.

Age of Sexual Maturity of Sandhill Cranes from Mid-Continental North America

1989 ◽  
Vol 53 (1) ◽  
pp. 43 ◽  
Author(s):  
Thomas C. Tacha ◽  
Donald E. Haley ◽  
Paul A. Vohs
Keyword(s):  
North America ◽  
Sexual Maturity ◽  
Sandhill Cranes

THE AUTOECIOUS SPECIES OF PUCCINIA ON HELIANTHEAE IN NORTH AMERICA

1967 ◽  
Vol 45 (12) ◽  
pp. 2267-2327 ◽  
Author(s):  
J. A. Parmelee
Keyword(s):  
New Species ◽  
Life Cycle ◽  
North America ◽  
Type Material ◽  
Material Distribution ◽  
New Combinations ◽  
New Varieties

Sixty-two taxa are recognized in this study of the species of Puccinia completing their life cycle on Heliantheae. Six new species are described: Puccinia guatemalensis Parmelee on Zexmenia spp. and Wedelia spp., P. ghiesbreghtii Parmelee on Wedelia ghiesbreghtii, P. abramsii Parmelee on Geraea viscida (= Encelia viscida), P. chloracae Parmelee on Viguiera spp., P. calanticariae Parmelee on Viguiera spp., and P. praetermissa Parmelee on Lagascea spp. Six new varieties are recognized: Puccinia electrae var. robusta Parmelee and P. electrae var. depressiporosa Parmelee on Zexmenia brevifolia, P. caleae var. cuernavacae Parmelee on Calea spp., P. cognata var. echinulata Parmelee on Verbesina spp., P. cognata var. fraseri Parmelee on Viguiera fraseri, and P. affinis var. triporosa Parmelee on Viguiera spp. Three taxa have been restored from synonomy under P. abrupta, viz. P. subglobosa, P. ximenesiae, and P. affinis, the last two parasitic on Verbesina spp., the first on Rhysolepis (= Viguiera). P. tithoniae, P. nanomitra, and P. ordinata, are reduced to synonomy with P. enceliae var. enceliae, P. iostephanes, and P. melampodii respectively. New combinations include: P. enceliae var. aemulans (Syd.) Parmelee and P. abrupta var. partheniicola (Jacks.) Parmelee. A key based on uredinial and telial characters, others based initially on the hosts, and a host index are provided. Each taxon is illustrated by a photomicrograph from type material. Distribution and host extensions, supplementary to those given in Arthur's Manual of the Rusts, are indicated.

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