Growth and development rates of Calanus finmarchicus nauplii during a diatom spring bloom

Growth and developmental rates were determined for copepodids of Calanus finmarchicus (Gunnerus) from experimental seawater mesocosms in a western Norwegian fjord. The instantaneous growth rates (g) from copepodid stage I (CI) to adult ranged from 0.08 to 0.10 d−1. Daily per capita mortality rate of the cohorts was as low as 0.012 d−1 (1.2% d−1). At local increasing temperatures (5.1 to 8.3 °C), development was equiproportional, and the cumulative median development time from egg to CV was approximately 65 d. CV moulted to males and females, and egg production was initiated. Enhancement of food resources by nutrient addition caused a 23.4% increase in growth rates from CI to adult. Additionally, copepodid stages showed a generally larger body size, carbon and nitrogen content and total storage lipid content (wax esters + triacylglycerols) in response to enhanced resources. Our data support an elsewhere proposed exponential-growth hypothesis; growth of the structural compartments and store lipids (mostly wax esters) was exponential during the copepodid stages. However, a sigmoidal pattern of growth best described growth of adult stages if reared at high resources, and depot lipid accumulation in late CVs and adults at high resources. Body nitrogen growth increased exponentially, however, no significant changes in nitrogen specific growth rates were found between individuals from low and high resources. CV and adults seem to have reached near-maximal weights at high resources, whereas structural weight continued to increase at low resources. Despite the differences in structural growth dynamics, cohort development was similar until the end of CV. During the onset of sexual differentiation, the male:female ratio and the adult:CV ratio were highest at high food resources, suggesting that the time used for the final moult depends on the feeding history of the copepods in relation to food quality and quantity. It appears that relatively small changes in food availability strongly influence the biochemical composition of C. finmarchicus copepodids.

The results of experimental studies on the influence of variable temperatures of egg incubation (37.8°C - 1...14 days; 39.5°C for 2 hours daily - 15-17 days; 37.5°C - 18 days; 37.0 °C - 19-20 days) on the growth and development of chicken embryos of egg crosses "Hisex Brown" and "Lohmann Brown" in different periods of embryogenesis. Under conditions of variable temperature incubation of eggs in the embryos of hens of the Lohmann Brown cross, compared with the Hisex Brown, there was a statistically significant increase in the absolute values of body weight by 12 (p=0.011), 14 (p=0.001), 15 (p= 0.000), 20 (p=0.000) days, body length - on days 6 (p=0.000), 8 (p=0.000), 9 (p=0.025), 13…16 (p=0.000) days. Differences in the rhythm of the growth of chicken embryos were established, accompanied by 5 critical stages of the growth rate of body weight and 6 critical stages of the growth rate of body length in the Haysex Brown cross, and in the embryos of the Lohmann Brown cross - 4 and 1 critical stages, respectively. Throughout the studied period of embryogenesis in the studied crosses, the highest intensity of the growth rate of weight and body length was noted in the embryonic period of development with a decrease towards the hatching period. The highest specific weight growth rate in the embryonic period is typical for embryos of chickens "Hisex Brown" (p=0.000), and body length - for embryos of the cross "Lohmann Brown" (p=0.047). In subsequent periods of embryonic development, the specific rate of growth in body weight and length decreased in both crosses. Differences in the specific rate of body weight growth in embryos of chickens "Hisex Brown" and "Lohmann Brown" in the prefetal (p=0.680) and fetal periods (p=0.477) were not found, and in the specific rate of body length growth - in the prefetal (p= 0.709), fetal periods (p=0.942) and hatching period (p=0.918). By the hatching period, the specific body weight growth rate prevailed in the Lohmann Brown embryos (p=0.000). The effect of exposure to variable incubation temperatures was accompanied by a higher percentage of chick hatchability of the Lohmann Brown cross (94.90%) compared to the Highsex Brown cross (91.90%). The results obtained indicate the feasibility of using the proposed mode of incubation with variable temperatures for cross-country chickens "Lohmann Brown".

Growth rate is a key demographic factor affecting survival and recruitment of marine fishes. Yet in the field, the patterns of change in growth rate with development and the effects of environmental variability on growth are poorly understood. We examined several factors that may contribute to the observed variability in recent (i.e. 2 to 4 d before sampling) growth and survival of Atlantic cod Gadus morhua and haddock Melanogrammus aeglefinus larvae on the southern flank of Georges Bank for the years 1995 through 1999. For both species, strong ontogenetic and seasonal trends in larval growth rates were apparent. A rapid initial increase in specific growth rate with lar- val size was observed in both species, followed by a stanza with little change in specific growth rate and finally a gradual increase with size to a maximum specific growth rate. For larva of any given size, growth rate increased as the season progressed. A variety of models were used to explore and describe the relations among growth rate, larval size, photoperiod, temperature and other variables. Generalized additive models (GAMs) with both larval size (protein content) and photoperiod terms explained 48% and 61% of the variability observed in recent growth of cod and haddock, respec- tively. Residuals from these models were used to examine the effects of other factors on estimated growth rates. Salinity, water density (sigma-t, σt), distance along the Bank, bottom depth, tempera- ture (T) and residual T (observed T minus the long-term mean for a given day of the year) explained small but significant portions of the residual variability in larval growth rates. These data and other considerations suggest that, while both increasing photoperiod and temperature contribute to the increase in larval growth rates observed each spring, photoperiod rather than temperature was the better proxy for the seasonal trend in larval growth rates between March and May on Georges Bank. Feeding conditions and growth of larval Atlantic cod and haddock were poor during the late winter and spring of 1995 compared with those from 1997 to 1999.

This study presents data on the effect ofdensity on growth and survival rateofAmphiprion ji-enatus. Four experiments were concluded: 2, 3, 4 and 5 inds/1. As a result, density clearly affected growth and survival rate ofA. ji-enatus. The highest growth and survival rate were achieved on 2 inds/1 (Specific Growth Rate- Length: 0.59%/day, growth rate - length: 26mm respective with survivor rate: 100%) but it is not different ji-om inds which were raised at 3 inds/1 (Specific Growth Rate- Length: 0.55%/day, growth rate length: 25.4mm respective with survival' rate: 100%) (base on statistical analysis). In the 4inds/1 experiment, survival was achieved 100% but growth rate was slower than two experiments before (Specific Growth Rate- Length:0.4%/day, growth rate - length: 24mm respective). The lowest growth and survival were achieved at 5 inds/1 (Specific Growth RateLength: 0.29%/day, growth rate - length: 23mm respective with suvivor rate: 93%). So, if we consider economic effect, we should choose to raise A.frenatus at 3 inds/1.

The scales of temporal and spatial variability of food resources in marine systems are determinant factors in the control of zooplankton populations. For adult copepods, egg production rates are dependent on the frequency of fluctuating food availability. However, very little is known about the effects of food fluctuations on the life-history parameters for early developmental stages of copepods. The growth and survival rates for naupliar stages of the marine copepod Acartia grani were studied in relation to food concentration and to experimentally induced fluctuations in food availabihty. Growth rates of early nauplii were highly dependent on food abundance, and were comparable to simultaneously estimated rates of adult production (egg production rates). Tolerance to starving conditions (survival time) increased through the cohort development For short-time fluctuations in food abundance (alternating, 12 h high food / 12 h low food conditions), growth rates of naupliar stages depended on the light conditions at which food was available. Lower frequency fluctuations (alternating, 24 or 48 h high food / low food conditions) significantly reduced both naupliar growth and survival rates. The sensitivity of growth rates to food fluctuation for naupliar stages, and their low tolerance to starving conditions, a r e further evidence to explain the confinement of A. grani to coastal habitats.

Growth rate, development time, and response to environmental stressors vary tremendously across organisms, suggesting trade-offs that are affected by evolutionary or ecological factors, but such trade-offs are poorly understood. Prior studies using artificially selected lines of Manduca sexta suggest that insects with high growth rates, long development time, and large body size are more sensitive to hypoxic or hyperoxic stresses, such as reactive oxygen species (ROS) production, but the mechanisms and specific life-history associations remain unclear. Here, we manipulated the social environment to differentiate the effects of size, growth rate, and development time on oxygen sensitivity of the giant mealworm, Zophobas morio. Crowding reduced growth rates but yielded larger adults as a result of supernumerary molts and longer development times. The juvenile performance (growth rate, development time, adult mass) of crowd-reared mealworms was less sensitive to variation in atmospheric oxygen than it was for individually reared animals, consistent with the hypothesis that high growth rates are associated with increased sensitivity to ROS. Life span in normoxia was extended by crowd rearing, perhaps due to the larger size and/or increased resources of the larger adults. Life spans of crowd-reared animals were more negatively affected by hypoxia or hyperoxia than life spans of individually reared animals, possibly due to the longer total stress exposure of crowd-reared animals. These data suggest that animals with high growth rates experience a negative trade-off of performance with greater sensitivity to stress during the juvenile phase, while animals with long development times or life spans experience a negative trade-off of greater susceptibility of life span to environmental stress.

Development rates, nitrogen- and carbon-specific growth rates, size, and condition were determined for the copepod Calanus finmarchicus reared at 3 temperatures (4, 8, and 12°C) at non-limiting food concentrations and 2 limiting food concentrations at 8°C in the laboratory. Development rates were equiproportional, but not isochronal. Naupliar stage durations were similar, except for non-feeding stages, which were of short duration, and the first feeding stage, which was prolonged, while copepodite stage durations increased with increasing stage of development. Under limiting food concentrations at 8°C, development rates were prolonged but similar relative patterns in stage durations were observed. Body size (length and weight) was inversely related to temperature and positively related to food concentration. Condition measurements were not affected by temperature, but were positively related to food concentration. Growth rates increased with increasing temperature and increased asymptotically with increasing food concentration. At high food concentrations, growth rates of naupliar stages were high (except for individuals molting from the final naupliar stage to the first copepodite stage, in which growth rates were depressed), while growth of copepodites decreased with increasing stage of development. Neither nitrogen nor carbon growth rates, the former a proxy for structural growth, were exponential over the entire life cycle, but rather sigmoidal. Carbon-specific growth rates were greater than nitrogen-specific growth rates, and this difference increased with increasing stage of development, reflecting an augmentation in lipid deposition in the older stages. However, nitrogen and carbon growth rates were more similar under food-limited conditions. Based on this study, we recommend that secondary production rates of Calanus finmarchicus and possibly other lipid-storing copepods not be estimated from egg production measurements alone, as has been suggested for other species of copepods, because growth, including structural growth, is not equivalent for all stages.

The growth rates of heterotrophic nanoflagellates (HNAN), mixotrophic cryptophytes, dinoflagellates and ciliates in field assemblages from Ace Lake in the Vestfold Hills (eastern Antarctica) and Lakes Fryxell and Hoare (McMurdo Dry Valleys, western Antarctica), were determined during the austral summers of 1996/1997 and 1997/1998. The response of the nanoflagellates to temperature differed between lakes in eastern and western Antarctica. In Ace Lake the available bacterial food resources had little impact on growth rate, while temperature imposed an impact, whereas in Lake Hoare increased bacterial food resources elicited an increase in growth rate. However, the incorporation of published data from across Antarctica showed that temperature had the greater effect, but that growth is probably controlled by a suite of factors not solely related to bacterial food resources and temperature. Dinoflagellates had relatively high specific growth rates (0.0057–0.384 h−1), which were comparable to Antarctic lake ciliates and to dinoflagellates from warmer, lower latitude locations. Temperature did not appear to impose any significant impact on growth rates. Mixotrophic cryptophytes in Lake Hoare had lower specific growth rates than HNAN (0.0029–0.0059 h−1 and 0.0056–0.0127 h−1, respectively). They showed a marked seasonal variation in growth rate, which was probably related to photosynthetically active radiation under the ice at different depths in the water column. Ciliates' growth rates showed no relationship between food supply and mean cell volume, but did show a response to temperature. Specific growth rates ranged between 0.0033 and 0.150 h−1 for heterotrophic ciliates, 0.0143 h−1 for a mixotrophic Plagiocampa species and 0.0075 h−1 for the entirely autotrophic ciliate, Mesodinium rubrum. The data indicated that the scope for growth among planktonic Protozoa living in oligotrophic, cold extreme lake ecosystems is limited. These organisms are likely to suffer prolonged physiological stress, which may account for the highly variable growth rates seen within and between Antarctic lakes.

Crossovers in seedling relative growth rates between low and high irradiance: analyses and ecological potential

Laboratory studies were conducted to measure growth, respiration, ingestion, and egestion for a leaf-shredding aquatic insect, Pteronarcys proteus (Plecoptera:Pteronarcyidae). These variables were measured for each of three cohorts found in a stream population, and all were a function of nymphal size and temperature. Relative growth rates (RGR) ranged from 0.031 to 0.0037 g g^-1 day^-1, with small nymphs growing fastest. Ingestion ranged from 5 to 40% of dry body weight per day. Respiration ranged from 330 to 980 μl O₂ g^-1 hr^-1. Respiration, ingestion, and growth were highest for smallest nymphs and decreased with increasing size of nymphs. Assimilation efficiencies also followed this pattern, except for female nymphs, for which both ingestion and assimilation efficiencies did not decline. Total assimilation by a population of Pteronarcys proteus in a mountain stream was estimated at 119 kcal m^-2 yr^-1, accounted for primarily by the two oldest cohorts present. Energy flow was greatest at and after autumn leaf abscission and lowest after spring emergence of adults. Annual energetics of the nymphal population were: ingestion = 906, growth = 41, respiration = 78, and egestion = 828 kcal/m². Annual production of three coexisting cohorts was 0.438 (Cohort 1), 3.158 (Cohort 2), and 4.182 (Cohort 3) g/m². In the stream, instantaneous daily growth rates (IDGR) were highest for smallest nymphs and ranged from 0.018 to no detectable growth. Correlations between temperature and IDGR were not significant except for the youngest cohort, for which growth rates were highest during higher temperatures. Larger nymphs, however, grew fastest after leaf-fall when temperatures were lower. The data show that growth rates of small nymphs were influenced by temperature and growth rates of larger nymphs were affected by food supply. Simulation of growth of nymphs under food-unlimited conditions supported this conclusion. Pteronarcys proteus consumed an estimated 41-64% of the litterfall in the study stream.

Under common environments, populations of laboratory reared (Grand Banks, GB and Gulf of Maine, GOM) and wild caught (Fortune Bay, FB and Bonavista Bay, BB; Newfoundland) juvenile cod Gadus morhua responded similarly to temperature change in specific growth rates, food conversion efficiencies, condition factors, liver water content, and muscle water content. However, GOM cod had higher condition factors, and showed differences from GB cod in phenotypic plasticity of hepatosomatic index to temperature. These differences were not present in a different population comparison between FB and BB cod. All populations had higher growth rates and food conversion efficiencies at warmer temperatures, and exhibited compensatory growth when temperature was increased. The results suggest relatively larger genetic differences between GB and GOM cod than between FB and BB cod, and indicate that the faster growth of southern populations in the wild is not due to a higher genetic capacity for growth rate.

The growth rate of two seabream species, was monitored during 2017. Seabreams Sparedentix hasta and Sparus aurata, were collected at age of 26 to 159 days and at 47 to 173 days for S. hasta and S. aurata respectively. The data obtained for age groups 47 to 159 days were used for comparison between the two species given 600 and 510 individuals for each species. They were raised from eggs under controlled ambient environmental conditions at the National Mariculture in the Kingdom of Bahrain. Early larvae were fed on live food such as Artemia and the fingerlings were fed on commercial feed. Weekly abiotic monitoring indicated that these species could tolerate slight fluctuations in these factors. Dissolved oxygen concentrations, in particular, ranged between 3.4 and 6 mg/l indicating their tolerance of occasional lower oxygen availability. The growth rate was exponential during the monitoring time. The linear correlations between body mass and body length were significant. Although some data indicated that the European seabream, S. aurata, can grow significantly faster (P≤ 0.05) than S. hasta, at certain age. In general, S. hasta had a higher instantaneous growth rate (Specific Growth Rate, SGR%). For example, SGR% was 20.29 from 54 to 61 days, whereas S. aurta had a value of 4.48%. SGR% ranged from 0.1 to 20.3% for S. hasta and from 0.2 to 19 % for S. aurata. Morphologically, S. aurata appears to have a more rounded and shorter body, but the native species, S. hasta, grows significantly longer and heavier. The differences in the rates of growth decreased with time as their body masses increased. There is an inverse relationship between body mass and the specific growth rate in both species. Monitoring SGR% using body mass or body length is one of the most useful indicators of production in mariculture. Attention needs to be considered however, to the husbandry and wellbeing of the cultured species.

AimA better understanding of plant communities can be achieved by incorporating data of traits and dynamics into surveys. Wood density is a good predictor for growth and mortality in trees, but to date, no studies of lianas include all three. We examine how liana communities respond to environmental gradients and forest fragmentation in terms of abundance, diversity, size structure, mortality, relative growth rate and wood density, and tested how the latter three are related to each other in liana species.LocationXishuangbanna, SW China.MethodsWe repeated a survey of lianas (stems >0.5 cm diameter) in 47 plots, distributed in forest fragments of various size, on different bedrock (limestone or sandstone), over an elevational range and across different topographic elements (ridge, slope, valley). We gathered wood density data for 116 of 166 species, covering 90% of all surveyed stems. We also determined relative growth rate, mortality, stem diameter and basal area.ResultsAt the species level, liana mortality and relative growth rate were lower at higher wood density, and mortality was higher with greater relative growth rate. At the plot level, liana communities in valleys had high relative growth and mortality rates as well as high abundance and diversity. Forest on limestone hosted few species but more large‐stemmed liana individuals, and communities had higher wood density weighted by basal area. Liana abundance, relative growth rates and mortality were greater and average wood density lower towards fragment edges, but the explanatory power of these models was low.ConclusionHabitat was the major factor shaping liana communities, whereas fragmentation was not an important predictor in our study. Resource‐rich environments such as valleys harbour diverse liana communities with high mortality and relative growth rates. This pattern matches earlier studies on survival/growth trade‐offs among plant species. The relationship between growth rates, mortality and wood density in lianas follows the same trade‐offs as found in trees.

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 119:99-110 (1995) - doi:10.3354/meps119099 Development of Pseudocalanus elongatus (Copepoda, Calanoida) cultured at different temperature and food conditions Klein Breteler, W. C. M., Gonzalez, S. R., Schogt, N. The pelagic copepod Pseudocalanus elongatus Boeck was bred 3 times from nauplius stages I and II to maturity at 5, 10, 15 and 20*C and at 4 different rations of autotrophic and heterotrophic food. The rate of development of the copepods increased with increasing temperature and food supply. The shortest generation times (from egg to adult) were 59 d at 5*C and 19 d at 15*C. The generation time nearly doubled when food concentration was very low. At 20*C mortality rates were high and development did not proceed faster than at 15*C. At all food levels the stage duration was generally constant (nearly isochronal), but the last 1 or 2 developmental stages took longer. The relationship between development time and temperature is described by Belehrádek's functions at different food levels. This relationship predicts a generation time of approximately 45 d during spring bloom conditions in the North Sea and about 30 d during summer due to food limitation. Field estimates from the literature are too scarce to evaluate the presumption of food limitation during summer conditions. Some evidence of a low critical food level was found compared to other North Sea copepod species. Together with a fast development rate at low temperatures, this may explain the numerical dominance of P. elongatus in the North Sea and the northeast Atlantic Ocean. Pseudocalanus . Copepods . Cultivation . Development . Temperature . Food Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 119. Publication date: March 23, 1995 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1995 Inter-Research.

Population growth, and other population characteristics, have been computed and made available online for over 2000 animal species in the Add-my-Pet (AmP) collection, assuming constant food and temperature environments. The AmP collection – online database of Dynamic Energy Budget model parameters, implied properties and referenced underlying data – provides an unique opportunity to study how energetics of individuals relates to population growth. For the comparisons of traits, we assume that the background hazard rate is zero, but aging applies to all species and ‘thinning’ to species with high reproduction rates. The new concept ‘thinning’ is a state-dependent hazard rate such that the feeding rate of a cohort does not change in time: the increase of individual feeding rates due to growth is exactly compensated by a reduction in numbers. Thinning affects population growth rate, but the impact differs substantially between species. Some 11% of species do not survive thinning, even at abundant food. The population growth rate relates to the underlying energetics; we discuss and suggest explanations for how population growth rates fit into all known patterns in the co-variation of parameter values: body size-scaling, metabolic acceleration, waste-to-hurry, supply-demand spectrum and altricial-precocial spectrum. We show that, after reproduction, age at puberty dominates population growth. The specific population growth rate scales with maximum body weight in the same way as the weight-specific respiration scales with body weight. DEB theory, which explains both, shows, however, that no direct relationship exists between the population growth rate and respiration. We suggest that the similarity in scaling results from the equality between specific population growth and specific growth rate at maximum growth of structure, and might be an evolutionary relict from times that life consisted of dividing unicellulars; population and body growth are directly connected for unicellulars. We show that the specific growth rate at maximum growth equals 1.5 times the von Bertalanffy growth rate, in a DEB context, which is a new interpretation of the latter growth rate. We expected the population growth rate to co-vary with specific somatic maintenance rate, based on a previously discovered pattern, called the waste-to-hurry strategy, where growth and reproduction are increased by simultaneously increasing assimilation and somatic maintenance in species that live off temporarily abundant food supplies. We did find this effect in ecdysozoa and spiralia, which comprise roughly 95% of animal species, but hardly so in tetrapods. The reason might be that specific somatic maintenance also co-varies with specific maturity levels at puberty for tetrapods. The scaled functional response at which the population growth rate is zero is very close to that at which puberty can just be reached in absence of thinning, and somewhat higher in presence of thinning. The specific population growth rate at abundant food correlates negatively with the functional response for which population growth rate is zero. It also correlates negatively with the precociality index, i.e. the ratio of maturity levels at puberty and birth: the more precocial, the larger neonate size, the smaller reproduction rate, especially in restricted taxa such as mammals and cartilaginous fish. Like other traits, the population growth rate shows considerable segregation among taxa, where mammals have a relatively low rate, glires a relatively high rate among mammals, followed by marsupials; afrotherians have the lowest population growth rates.