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Registros recuperados: 9
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Sexual and asexual reproduction in Didemnum rodriguesi (Ascidiacea, Didemnidae) Iheringia, Sér. Zool.
Ritzmann,Nicole F.; Rocha,Rosana M. da; Roper,James J..
Sexual and asexual reproduction and associated population dynamics were investigated in the colonial ascidian Didemnum rodriguesi Rocha & Monniot, 1993 (Didemnidae) in southern Brazil. Investment in sexual (production of new individuals) and asexual (colony growth) reproduction was compared between seasons. Permanently marked quadrats were repeatedly photographed to measure changes in colonies. Eggs and larvae were counted monthly in collected colonies. This species alternates seasonally between sexual (summer) and asexual (winter) reproduction. In summer, colonies were smaller, brooded eggs and larvae and recruitment rates were greater, while in winter, colony size was larger and eggs and larvae were absent. There is a relationship between...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Reproductive investment; Sexual reproduction; Fragmentation; Tunicates.
Ano: 2009 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0073-47212009000100015
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Estimating age at maturation and energy-based life-history traits from individual growth trajectories with nonlinear mixed-effects models ArchiMer
Brunel, Thomas; Ernande, Bruno; Mollet, Fabian M.; Rijnsdorp, Adriaan D..
A new method is presented to estimate individuals’ (1) age at maturation, (2) energy acquisition rate, (3) energy expenditure for body maintenance, and (4) reproductive investment, and the multivariate distribution of these traits in a population. The method relies on adjusting a conceptual energy allocation model to individual growth curves using nonlinear mixed-effects modelling. The method’s performance was tested using simulated growth curves for a range of life-history types. Individual age at maturation, energy acquisition rate and the sum of maintenance and reproductive investment rates, and their multivariate distribution, were accurately estimated. For the estimation of maintenance and reproductive investment rates separately, biases were observed...
Tipo: Text Palavras-chave: Bioenergetics growth model; Individual growth trajectory; Life-history trade-offs; Energy acquisition; Maintenance; Reproductive investment; Sexual maturation.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00124/23537/21378.pdf
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Spawning energetics and otolith microchemistry provide insights into the stock structure of bonga shad Ethmalosa fimbriata ArchiMer
Doering, Julian; Wagner, Carola; Tiedemann, Maik; Brehmer, Patrice; Ekau, Werner.
The gross energy content of spawning batches and the microchemistry of sagittal otoliths in individual female bonga shad Ethmalosa fimbriata were compared between contrasting sampling sites at the Senegalese southern coast and inside the hypersaline Sine Saloum Estuary. Results show that females spawning in the estuary's middle reaches invested almost three times more energy into reproduction (115 +/- 65 J g(-1) body mass) than their neritic counterparts (39 +/- 34 J g(-1) body mass). Also, female otolith levels of Ba:Ca, Sr:Ca and Zn:Ca either differed significantly between study sites or could be linked to heterogeneous environmental variables. A quadratic discriminant function analysis provided evidence of segregated spawning populations of E. fimbriata...
Tipo: Text Palavras-chave: Clupeidae; Inverse estuary; Oocyte; Reproductive investment; Senegal; Stock discrimination; Spawning components.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00484/59567/62545.pdf
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Reproductive investment in Atlantic cod populations off Newfoundland: Contrasting trends between males and females ArchiMer
Baulier, Loic; Morgan, M. Joanne; Lilly, George R.; Dieckmann, Ulf; Heino, Mikko.
Life history theory predicts selection for higher reproductive investment in response to increased mortality among mature individuals. We tested this prediction over the period from 1978 to 2013 for three populations of Atlantic cod (Gadus morhua) off Newfoundland. These populations were heavily fished for a long period. We considered changes in standardized gonad weight as a proxy for changes in gonadal investment. We accounted for the allometry between gonad and body weight, individual body condition, water temperature, and potential spatial and density-dependent effects. Males display significant temporal trends in gonadal investment in all populations; in agreement with theoretical predictions, these trends show increased gonadal investments during the...
Tipo: Text Palavras-chave: Reproductive investment; Fisheries-induced evolution; Atlantic cod; Gonad weight.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00400/51111/51893.pdf
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Temporal trends in age and size at maturation of four North Sea gadid species: cod, haddock, whiting and Norway pout ArchiMer
Marty, Lise; Rochet, Marie-joelle; Ernande, Bruno.
Younger ages and smaller sizes at maturation have been observed in commercial fish stocks over the last century. We establish that age and length at 50% proportion mature (i.e. the proportion of mature individuals in a population or the probability that an individual is mature) decreased from the 1970s to the 2000s in North Sea cod Gadus morhua, haddock Melanogrammus aeglefinus and whiting Merlangius merlangus, but not in Norway pout Trisopterus esmarkii. The potential contributions of demography, phenotypic plasticity and evolution to these trends were assessed. First, maturation trends were extricated from demographic effects and growth-dependent plasticity by estimating probabilistic maturation reaction norms (PMRNs). PMRN midpoints have significantly...
Tipo: Text Palavras-chave: Probabilistic maturation reaction norm; Demography; Phenotypic plasticity; Fisheries-induced evolution; Life-history strategy; Maturity; Growth; Reproductive investment.
Ano: 2014 URL: https://archimer.ifremer.fr/doc/00180/29152/27559.pdf
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Spatial patterns in the condition index of the wild Pacific oyster Crassostrea gigas in a macrotidal coastal ecosystem: Influence of tidal processes and beyond ArchiMer
Gasmi, Sonia; Bernard, Ismael; Pouvreau, Stephane; Maurer, Daniele; Schaal, Gauthier; Ganthy, Florian; Cominassi, Louise; Allain, Gwenhael; Sautour, Benoit; David, Valerie.
In macrotidal coastal ecosystems, spatial heterogeneity of the water column properties is induced by both oceanic and continental influences. Hydrodynamic processes generate a land-sea gradient of environmental conditions, affecting the biological performances of sedentary organisms. The aim of the present study is to establish an extensive spatial assessment in the reproductive investment of the wild Pacific oyster Crassostrea gigas in Arcachon Bay. This is done by looking for a relationship between the Lawrence and Scott condition index (LSCI) and two tidal processes: the immersion level (IL) and the local oceanic flushing time (LoFt). The LSCI of C. gigas was assessed, just before gamete release, at 68 sampling stations in Arcachon Bay. Oyster...
Tipo: Text Palavras-chave: Reproductive investment; Crassostrea gigas; Macrotidal lagoon; Immersion level; Oceanic flushing; Environmental variability.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00357/46803/46670.pdf
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Gametogenesis, reproductive investment, and spawning behavior of the Pacific giant oyster Crassostrea gigas: evidence of an environment-dependent strategy ArchiMer
Enriquez-diaz, M.; Pouvreau, Stephane; Chavez-villalba, J.; Le Pennec, M..
The progress of gametogenesis was studied in oysters Crassostrea gigas having the same origin (Tremblade), but cultured during 1 year in two distinctive French marine areas, the Baie des Veys and Marennes-Ol,ron. We assessed seasonal changes in the reproduction cycle on the basis of stereological techniques to estimate reproductive investment and measurement of gonad evolution area by quantitative histology. From a qualitative point of view, both oyster groups presented typical reproductive stages, but showed differential timing, in particular during the sequence of spawning and duration of the re-absorption stage. Oysters in Baie des Veys had a single partial spawning in August and a re-absorption stage that extended until winter. Oysters in...
Tipo: Text Palavras-chave: Stereology; Reproductive investment; Pacific oysters; Image analysis; Gametogenesis; Crassostrea gigas.
Ano: 2009 URL: http://archimer.ifremer.fr/doc/2009/publication-7300.pdf
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Litter size, effects of maternal body size, and date of birth in South American scorpions (Arachnida: Scorpiones) Rev. Bras. Zool.
Outeda-Jorge,Sabrina; Mello,Thayná; Pinto-da-Rocha,Ricardo.
We present new data on litter size and date of birth (month) for 21 South American scorpions species. We provide data for one katoikogenic species, the liochelid Opisthacanthus cayaporum Vellard, 1932 (offspring = 3; birth month: Jan); and for several apoikogenic species, such as the bothriurids Bothriurus araguayae Vellard, 1934 (53; Sep), B. rochensis San Martín, 1965 (22-28; Jan, Aug); the buthids Ananteris balzanii Thorell, 1891 (10-34; Jan-Mar), Physoctonus debilis (Koch, 1840) (2; Sep), Rhopalurus amazonicus Lourenço, 1986 (19; Nov), R. lacrau Lourenço & Pinto-da-Rocha, 1997 (30; Dec), R. laticauda Thorell, 1876 (41; Nov), R. rochai Borelli, 1910 (11-47; Dec-Jan, Mar-Apr), Tityus bahiensis (Perty, 1833) (4-23; Oct-Mar), T. clathratus Koch,...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Bothriuridae; Buthidae; Chactidae; Liochelidae; Reproductive investment.
Ano: 2009 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-46702009000100008
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Latitudinal comparisons of reproductive traits in five Brachyuran species along the Chilean coast RChHN
BRANTE,ANTONIO; CIFUENTES,SANDRA; PÖRTNER,HANS-OTTO; ARNTZ,WOLF; FERNÁNDEZ,MIRIAM.
Understanding large-scale patterns in reproductive investment and fecundity of marine invertebrates is important for determining the critical environmental variables affecting reproduction and thus, the spatial patterns of population dynamics. However, information on patterns of reproduction of marine invertebrates at large spatial scales are either scarce, or have been conducted by mixing species with contrasting modes of development. Brachyuran crabs are an ideal group to analyze large-scale patterns of reproduction not only because many species are commercially exploited, but also because they show a single mode of larval development and wide distributional ranges. Here, we report latitudinal patterns of reproductive variables in five Brachyuran crab...
Tipo: Journal article Palavras-chave: Reproductive investment; Fecundity; Brooding; Crabs; Embryo loss.
Ano: 2004 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2004000100003
Registros recuperados: 9
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