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Somatic Growth Rate (somatic + growth_rate)
Selected AbstractsEradication of the invasive Pseudorasbora parva results in increased growth and production of native fishesECOLOGY OF FRESHWATER FISH, Issue 1 2009J. R. Britton Abstract,,, The topmouth gudgeon, Pseudorasbora parva, has been described as Europe's most invasive fish. To control their UK invasion, some lentic populations at risk of causing fluvial dispersal have been eradicated. The first of these operations was from a lake in north-west UK in March 2005 using rotenone application; prior to eradication, their mean density was estimated as 6.1 m,2 whereas since eradication, no P. parva have been recorded. Prior to rotenone application, the majority of native fishes were removed, held off-site and reintroduced following degradation of rotenone to safe levels. In the three growth seasons since their reintroduction and P. parva eradication, the abundance, somatic growth rate and production of roach Rutilus rutilus and common bream Abramis brama have increased significantly; production is now driven by a lower number of comparatively larger, faster growing individuals. These data suggest that the eradication of this P. parva population has been highly beneficial for the growth, recruitment and production of these native species. [source] Growth and reproduction of three cladoceran species from a small wetland in the south-eastern U.S.A.FRESHWATER BIOLOGY, Issue 4 2003A. M. Lemke SUMMARY 1.,Growth, reproduction and life-history parameters were measured for three cladoceran species from a small south-eastern wetland, U.S.A. Simocephalus serrulatus, Diaphanosoma brachyurum and Scapholeberis mucronata juveniles were reared at temperatures between 10 and 25 °C on natural food resources. 2.,Growth rate increased with temperature and decreased with individual size for all three species. Maximum somatic growth rate was higher for Simocephalus (49,72% day,1) and Diaphanosoma (21,91% day,1) than for Scapholeberis (11,45% day,1). Multiple regression equations were developed which predict temperature- and mass-specific growth rates for each species. 3.,Scapholeberis egg production was positively related to temperature; however, maximum egg production occurred at intermediate temperatures for Simocephalus and Diaphanosoma. Mean cumulative egg production was higher for Scapholeberis (28,92 eggs per female) than for Simocephalus (18,25 eggs per female) and Diaphanosoma (1,41 eggs per female), and was related to differences in reproductive strategy and survival. 4.,Survival was inversely related to temperature in most cases. For all three cladocerans, the intrinsic rate of increase (r) and net reproductive rate (R0) increased with temperature, whereas generation time (G) decreased. Greater egg production by Scapholeberis compared with the other two cladocerans was consistent with higher R0 values for Scapholeberis at any given temperature. Although r was very similar among species, G was typically longer for Scapholeberis than for Simocephalus and Diaphanosoma. 5.,This analysis provides basic information about the population parameters of these coexisting wetland species, and the growth rate models can be applied to field data to determine production dynamics. [source] Ontogenetic Shifts in the Ability of the Cladoceran, Moina macrocopa Straus and Ceriodaphnia cornuta Sars to Utilize Ciliated Protists as Food SourceINTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 3 2008Ram Kumar Abstract The ontogenetic diet shifts and age specific ability of the two cladoceran species Moina macrocopa and Ceriodaphnia cornuta to derive energy from ciliated protists have been investigated in laboratory. The postembryonic developmental rates and life table demography (longevity, age and size at first reproduction, fecundity and intrinsic rate of natural increase) of the cladocerans have been elucidated on algae (Chlorella vulgaris) and the ciliated protists (Tetrahymena pyriformis, Colpoda (c.f.) steini) as food. For either of the cladoceran, the somatic growth rate and average body size at first reproduction were higher with algal diet. During initial stages of development (0,5 days), either cladoceran realized higher rate of somatic growth on algal diet, subsequently ciliated protists supported significantly higher growth rate than the alga. Algal and ciliate diets did not differ in maximum body size (C. cornuta: 539,554 ,m; M. macrocopa: 1274.8,1309 ,m) reached by either of the cladocerans. The maximum body sizes were larger than size at first reproduction with either of the ciliated protists, however, with algal diet the maximum body sizes did not differ from the size at first reproduction in each case. In case of C. cornuta the generation time (20.5 ± 0.3 days on ciliate; 15.6 ± 0.17 days on algal diet), reproductive rates (net reproductive rate: 20.05 ± 3.2 on ciliate; 15.5 ± 1.2 on algal diet), and average life expectancy at hatching (27 ± 0.8 days on ciliate; 22.7 ± 0.71 days on alga) were higher, whereas the size at first reproduction (482 ,m on ciliate; 521 ,m on alga) was smaller with the ciliate than with an algal diet. The algal and the ciliate diets did not differ in survival (life expectancy at hatching: 9.2 ± 0.7 days) and fecundity (NRR: 23.6 ± 2.4) for M. macrocopa. The two ciliates used in the experiment did not differ in their performance as food source for either cladoceran species. Our results suggest that both the cladoceran species are able to utilize smaller ciliate (e.g., T. pyriformis, C. (c.f.) steini) as food; however with differential ability to derive energy from the ciliate diet and this ability is size and age structured in both cases. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Temperature adaptation in a geographically widespread zooplankter, Daphnia magnaJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 3 2000Mitchell Evidence for temperature adaptation in Daphnia magna was inferred from variation in the shape of temperature reaction norms for somatic growth rate, a fitness-related trait. Ex-ephippial clones from eight populations across Europe were grown under standardized conditions after preacclimation at five temperatures (17,29 °C). Significant variation for grand mean growth rates occurred both within populations (among clones) and between populations. Genetic variation for reaction norm shape was found within populations, with temperature-dependent trade-offs in clone relative fitness. However, the population average responses to temperature were similar, following approximately parallel reaction norms. The among-population variation is not evidence for temperature adaptation. Lack of temperature adaptation at the population level may be a feature of intermittent populations where environmentally terminated diapause can entrain the planktonic stage of the life-history within a similar range of temperatures. [source] Linking growth to environmental histories in central Baltic young-of-the-year sprat, Sprattus sprattus: an approach based on otolith microstructure analysis and hydrodynamic modellingFISHERIES OCEANOGRAPHY, Issue 6 2006HANNES BAUMANN Abstract Otolith microstructure analysis and hydrodynamic modelling were combined to study growth patterns in young-of-the-year (YoY) sprat, Sprattus sprattus, which were sampled in October 2002 in the central Baltic Sea. The observed ,window of survival', approximated by the distribution of back-calculated days of first feeding (DFF), was narrow compared to the extended spawning season of sprat in the Baltic Sea (mean± SD = 22 June ± 14.1 days) and indicated that only individuals born in summer survived until October 2002. Within the group of survivors, individuals born later in the season exhibited faster larval, but more rapidly decreasing juvenile growth rates than earlier born conspecifics. Back-calculated larval growth rates of survivors (0.48,0.69 mm day,1) were notably higher than those previously reported for average larval sprat populations, suggesting that the YoY population was predominantly comprised of individuals which grew faster during the larval stage. Daily mean temperatures, experienced across the entire YoY population, were derived from Lagrangian particle simulations and correlated with (1) detrended otolith growth and (2) back-calculated, daily somatic growth rates of survivors. The results showed that abrupt changes in ambient temperature can be detected in the seasonal pattern of otolith growth, and that higher temperatures led to significantly faster growth throughout the entire age range of YoY sprat. [source] | ||||||||||