Growth Rate In Fresh Water Research Articles

Integrating microalgae-based wastewater treatment, biostimulant production, and hydroponic cultivation: a sustainable approach to water management and crop production.

A natural appearing microalgae-bacteria consortium was used to process urban wastewater. The process was done in an 80m2 raceway reactor and the results were compared to an identical reactor operated using freshwater supplemented with commercial fertilisers. The biomass harvesting was done using commercial ultrafiltration membranes to reduce the volume of culture centrifuged. The membrane allowed achieving a biomass concentration of ∼9-10gL-1. The process proposed avoids the use of centrifuges and the drying of the biomass, two of the most energy consuming steps of conventional processes. The specific growth rate in freshwater and the wastewater-based media was estimated as 0.30 ± 0.05 and 0.24 ± 0.02 days-1, respectively (p < 0.05). The maximum concentration reached at the end of the batch phase was 0.96 ± 0.03 and 0.83 ± 0.07gL-1 when the biomass was produced using freshwater and wastewater, respectively (p < 0.05). The total nitrogen removal capacity of the system was on average 1.35gm-2·day-1; nitrogen assimilation into biomass represented 60%-95% of this value. Furthermore, the P-PO4 3- removal capacity of the system varied from 0.15 to 0.68gm-2·day-1. The outlet effluent of the reactor was used as a nutrient source in the hydroponic production of zucchini seedlings, leading to an increase in the root dry weight and the stem diameter compared to the water alone. The produced biomass showed potential for use as feedstock to produce plant biostimulants with positive effects on root development and chlorophyll retention.

Effects of different photoperiod regimes on the smoltification and seawater adaptation of seawater-farmed rainbow trout (Oncorhynchus mykiss): Insights from Na+, K+–ATPase activity and transcription of osmoregulation and growth regulation genes

Photoperiod is thought to be the main zeitgeber that induces smoltification in salmonids. However, its effects on the smoltification of rainbow trout (Oncorhynchus mykiss) are not fully understood and no published data documents the effects of the photoperiod regime currently used commercially, continuous light (LL). The present study compared the effect of four different photoperiod regimes (i.e. advanced phase photoperiod (APP), delayed phase photoperiod (DPP), LL and simulated natural photoperiod (SNP)) on the smoltification and growth of juvenile rainbow trout during their freshwater phase of winter-spring and the following summer post smolt phase. Smoltification was evaluated by monitoring gill Na+,K+–ATPase (NKA) activity and transcription of NKA α-subunit isoforms 1a and 1b, and Na+,K+,2Cl‐cotransporter 1a. Growth was measured as specific growth rate of both length and weight, and through molecular growth proxies such as the levels of circulating insulin-like growth factor 1 (IGF-I) in plasma and transcription of igf-I, igf binding protein 1b (igfbp1b), growth hormone receptor 1 (ghr1) and cathepsin L (ctsl) in the liver. Results indicate that APP induces a longer smolt window and higher levels of plasma IGF-I in both freshwater and seawater (two months post transfer), while DPP led to a shorter smolt window, lower plasma IGF-I levels in freshwater and seawater, an earlier decrease in liver igf-I and ctsl transcription in freshwater (as seen by modelling over time) and lower specific growth rate in freshwater. The transcription analysis of osmoregulatory genes complemented NKA activity and allowed for the detection of a transient response to light and of differences between the osmoregulatory capacity of parr and desmolted fish. Furthermore, an upregulation of the liver transcription of igf-I, ghr1 and ctsl was found in all treatments during the smolt window, which corresponded to the periods with highest growth. Finally, both plasma IGF-I and liver igf-I in seawater were found to be significantly correlated to fish growth in seawater. However, our data did not show that plasma IGF-I prior to seawater transfer could be used as a reliable predictor of growth in seawater. Overall, and especially when compared with other salmonid species, photoperiod seems to be a weaker inducer of smoltification in rainbow trout, according to the parameters that were tested, suggesting that other environmental cues might be more important drivers of this process.

Effects of salinity changes on growth performance and survival of climbing perch, Anabas testudineus (Bloch, 1795)

An experiment was carried out to find the salinity tolerance capability and growth performance of Climbing Perch, Anabas testudineus (Bloch, 1795). Anabas testudineus commonly cultured fish in Bangladesh was reared in laboratory conditions at different salinities of 0, 3, 6, 9, 12, 15, 18 and 21‰ for 60 days. Hundred per cent survivals were detected at 0, 3, 6 and 9‰ salinity while 100% mortality was recorded at 18 and 21‰ salinity. Various responses to threat and feeding were observed among the fish in different treatments. Lowest feed conversion ratio was found in the control group while the highest was detected at 15‰ salinity. On the other hand, decreasing trend of specific growth and average growth rate were observed in A. testudineus fingerlings from 0 to 15‰ salinity. Significantly higher specific growth rate and average growth rate were detected in A. testudineus fingerlings reared at 0 - 6‰ salinity (p &lt; 0.05). The present study suggests that Climbing Perch fingerlings can be reared at fresh water growth rates in coastal water with salinity up to 6‰.Dhaka Univ. J. Biol. Sci. 25(1): 65-73, 2016

Effects of hexazinone and atrazine on the physiology and endocrinology of smolt development in Atlantic salmon

Exposure to hexazinone (HEX) and atrazine (ATZ), highly mobile and widely used herbicides along rivers in the United States, is potentially harmful to Atlantic salmon, which have been listed as an endangered species. To determine the effects of these contaminants on smolt development, juvenile Atlantic salmon were exposed under flow-through conditions to 100 μg l −1 HEX, 10 and 100 μg l −1 ATZ in fresh water (FW) for 21 days at 10 °C beginning in mid-April. Twelve fish per treatment were sampled in FW, following a 24 h seawater (SW) challenge and after growth for 3 months in SW. Exposure to 100 μg l −1 HEX or 10 μg l −1 ATZ caused no mortalities of smolts in FW or after SW challenge, while 9% of the fish exposed to 100 μg l −1 ATZ died during exposure. Fish exposed to 100 μg l −1 ATZ reduced feeding after 10 days of exposure and had an impaired growth rate in FW and during the first month in SW; compensatory growth occurred in the second and third month in SW. HEX and ATZ at 10 μg l −1 exposure had no effect on plasma levels of cortisol, growth hormone (GH), insulin growth factor I (IGF-I), thyroxine (T 4) and plasma 3,5,3′-triiodo- l-thyronine (T 3), Cl −, Mg 2+, Na +, Ca 2+ in FW or after SW challenge. FW smolts exposed to 100 μg l −1 ATZ had decreased plasma Cl −, Mg 2+, Na + and Ca 2+ ions and increased cortisol. No effect on plasma levels of GH, IGF-I, T 4 or T 3 was found in FW smolts exposed to 100 μg l −1 ATZ. Following SW challenge, fish previously exposed to 100 μg l −1 ATZ had significant increases in hematocrit, plasma cortisol, Cl −, Mg 2+, Na +, Ca 2+ and a decrease in T 4 and T 3. It is concluded that under the conditions imposed in this study, HEX does not affect salinity tolerance of Atlantic salmon smolts, while ATZ causes ionoregulatory, growth and endocrine disturbance.

Temperature influence on the development and loss of seawater tolerance in two fast-growing strains of Atlantic salmon

Development of hypo-osmoregulatory ability, gill Na +,K +-ATPase activity, condition factor and growth in Atlantic salmon during parr–smolt transformation was studied in a 2×3 factorial design with three temperatures (12.0, 8.9 °C and ambient, 2.4–11.9 °C, mean: 6.0 °C) and two farmed strains of smolts (Mowi and AquaGen). The development of hypo-osmoregulatory ability and gill Na +,K +-ATPase activity were significantly influenced by freshwater temperature. In smolts raised at 12.0 °C, maximum gill Na +,K +-ATPase activity was reached in late April, compared with late May and mid-June in the 8.9 °C and ambient groups, respectively. In all groups, peak gill Na +,K +-ATPase activity was seen 350 degree days (d °C) after the onset of the smolt-related increase in enzyme activity (30 March) The period of high enzyme activity (>90% of maximum) lasted approximately 250 d °C. No distinct peak level in gill Na +,K +-ATPase activity was seen in the AquaGen strain at ambient temperature. Elevated temperatures also accelerated the loss of hypo-osmoregulatory capacity. In all groups, gill Na +,K +-ATPase activity reached pre-smolt levels approximately 500 d °C after the calculated peak level. Growth rate in freshwater was influenced by strain, temperature and their interaction, with the Mowi strain showing a higher growth rate than the AquaGen strain at 8.9 °C and ambient temperatures. Following transfer to seawater, a higher growth rate was recorded in smolts from the Mowi strain than the AquaGen strain from the ambient temperature regime. Temperature influences the development and loss of smolt characteristics in both strains, and has long-term effects on post-smolt performance in seawater.

Influence of salinity on food consumption, growth and energy conversion efficiency of common carp ( Cyprinus carpio) fingerlings

Food consumption, growth rate, digestibility, nitrogenous excretion rate and oxygen consumption rate of common carp ( Cyprinus carpio L.) fingerlings (5.6–8.8 cm in body length) were measured at salinities from 0.5 to 14.5%. at a temperature of 13.8–22.5 °C for 92 days. The specific growth rate in weight gain was high (2.32% day −1) in fresh water, reduced with increase in salinity, and reached a negative percentage at 10.5‰. The daily food consumption rate of the fingerlings was high (4.39 ± 1.53%) in fresh water and diminished with an increase in salinity up to 6.5‰. The fingerlings had a high digestibility (96.6 ± 1.99%) of dry matter in feed at a salinity of 2.5%. and in fresh water. The range of the nitrogenous excretion rate (μg N g −1 day −1) at various salinities varied as follows: 2.5%., 24.77 ± 11.36; fresh water, 41.51 ± 5.85; 4.5%., 55.69 ± 10.49; 6.5%., 64.75 ± 5.00; 8.5%., 101.20 ± 25.47; 10.5%., 130.96 ± 12.96. Oxygen consumption rate was low in fresh water and at 2.5%. salinity. The high growth rate in fresh water was correlated with the high daily food consumption rate and high digestibility of feed.

Does Early Growth Cause a Phenotypically Plastic Response in Egg Production of Atlantic Salmon?

1. To evaluate how differences in juvenile and subadult growth influence egg size and fecundity, we investigated wild and hatchery reared Atlantic Salmon smolts originating from the River Imsa population. The smolts were individually tagged and released into a Norwegian river. Specific growth rate of hatchery reared juveniles in fresh water averaged 1.38 times higher than that of wild conspecifics. Specific growth rate at sea of the subadults, on the other hand, was 1.14 times higher for wild than hatchery reared fish. 2. Mean egg weight increased with adult body weight. On average, eggs of wild fish were 1.12 times heavier than those of hatchery reared fish of corresponding sea ages. 3. Somatic fish weight (total fish weight less egg weight) explained 27% of the variance in egg weight in wild, 40% in hatchery reared salmon and 30% for the combined sample. Moreover, juvenile growth rate in fresh water as a second independent variable, significantly improved the explanatory power (r 2 = 0.43 for wild, 0.46 for hatchery salmon and 0.48 for the combined sample). Neither growth rate at sea nor length increment as juveniles in fresh water (smolt length) added significantly to the explanatory power. 4. Fecundity increased with somatic weight in both wild (r 2 = 0.81) and hatchery reared fish (r 2 = 0.74), with hatchery fish having about 30% more eggs for a given body size than wild females. By adding specific growth rate in fresh water as a second independent variable, 76% of the variance in fecundity of hatchery fish was explained. In wild fish, the addition of egg weight as the second independent variable increased the coefficient of determination of the regression model to 0.88. Use of length increment at sea and smolt length as independent variables did not improve the explanatory power. 5. Total ovary weight increased with somatic weight (r 2 = 0.83) and the pattern was similar for wild and hatchery reared fish. Neither growth rate in fresh water nor at sea increased the explanatory power of the regression model.

Differentiation in juvenile growth and bimodality patterns between northern and southern populations of Atlantic salmon (Salmo salar L.)

Juvenile Atlantic salmon, Salmo salar, from two contrasting populations that had been reared under identical conditions differed in freshwater growth rates and the development of bimodality in length–frequency distributions. Segregation by size started at least a month earlier in the northern (River Shin, northern Scotland) than in the southern population (River Narcea, northern Spain). Northern fish initially grew faster and entered the upper modal group at a larger size (about 100 mm) than did southern fish (about 90 mm). However, the percentage of fish in the upper modal group was greater for the southern population and they grew fastest over winter and during the spring leading up to smolting, and were larger at the smolt stage. By late winter, the individual growth rates of upper modal fish were inversely correlated with their body length in December. These results suggest the existence of genetic differences between populations in the expression of growth bimodality in juvenile Atlantic salmon. This may indicate that size and growth rate thresholds determining the developmental pathway associated with age at smolt metamorphosis may vary between populations as a function of both smolt size and expected growth opportunity during winter and spring.

Effects of photoperiod and temperature on growth and parr-smolt transformation in Atlantic salmon ( Salmo salar L.) and subsequent performance in seawater

Potential Atlantic salmon ( Salmo salar L.) 1 + smolts were reared during late winter and spring in a factorial design combining elevated, 12–13°C ( e), or ambient ( a) temperature with four photoperiod regimes: simulated natural photoperiod, 60°N (LN60, control); simulated natural photoperiod, 70°N (LN70); simulated natural photoperiod, 1 month phase delayed (LD60); and continuous light (LL). Growth rate in fresh water was enhanced by elevated water temperature and continuous light. No consistent differences were seen among the LN70 and LN60 groups at the two temperature regimes, whereas the LD60 e group had a lower growth rate than LN60 e. Condition factor decreased between February and April on LL under both thermal regimes. For the other groups on elevated temperature, condition factor decreased from March onwards, while no clear reduction was seen among the LN60 a, LN70 a or LD60 a groups. Based on morphological changes, increase in hypo-osmoregulatory ability and gill Na +,K +-ATPase activity, the LN60 e, LN70 e and LD60 e groups developed smolt characters in April or early May, while corresponding groups on ambient temperature did not complete smoltification until late May or early June. Fish were transferred to seawater in mid-June and measured again in mid-November. Groups reared on ambient temperature had higher growth rates in seawater than corresponding groups from elevated temperature. Smolts from LD60 had lower growth rate than did those from LN60 and LN70, indicating that the delay in photoperiod influenced the completion and/or timing of smolting. The LL e group had the lowest growth rate in seawater, suggesting that the continued exposure to LL and elevated temperature interfered with the normal course of parr-smolt transformation.

Latitudinal clines in life‐history variables of anadromous brown trout in Europe

Based on published data, we reviewed clinal variations in life‐history characteristics of anadromous brown trout Salmo trutta from 102 European rivers at latitudes between 54 and 70° N. Growth rate in fresh water, mean smolt age, mean sea age at first sexual maturity, proportion of repeal spawners among adults, longevity, and length of adult life span exhibited latitudinal clines. Brown trout grew faster in fresh water, smolted and matured younger, lived fewer years but spawned more times in the south than in the north. The life‐history traits studied were often correlated. Longevity, smolt age and sea age at maturity were negatively and smolt length and proportion of repeat spawners among adults were positively correlated with growth rate in fresh water. Longevity was positively correlated with smolt age and sea age at maturity. The latter also increased with increasing smolt age. None of these significant correlations among life history variables, except for those between smolt age and parr growth and proportion of repeat spawners and parr growth, are latitudinal effects. We do not know to what extent the latitudinal variation in life–history traits reflects phenotypic plasticity and to what extent it is caused by inherited differences among populations.

The effect of temperature and algal biomass on bacterial production and specific growth rate in freshwater and marine habitats

We analyzed heterotrophic, pelagic bacterial production and specific growth rate data from 57 studies conducted in fresh, marine and estuarine/coastal waters. Strong positive relationships were identified between 1) bacterial production and bacterial abundance and 2) bacterial production and algal biomass. The relationship between bacterial production and bacterial abundance was improved by also considering water temperature. The analysis of covariance model revealed consistent differences between fresh, marine and estuarine/coastal waters, with production consistently high in estuarine/coastal environments. The log-linear regression coefficient of abundance was not significantly different from 1.00, and this linear relationship permitted the use of specific growth rate (SGR in day(-1)) as a dependent variable. A strong relationship was identified between specific growth rate and temperature. This relationship differed slightly across the three habitats. A substantial portion of the residual variation from this relationship was accounted for by algal biomass, including the difference between marine and estuarine/coastal habitats. A small but significant difference between the fresh- and saltwater habitats remained. No significant difference between the chlorophyll effect in different habitats was identified. The model of SGR against temperature and chlorophyll was much weaker for freshwater than for marine environments. For a small subset of the data set, mean cell volume accounted for some of the residual variation in SGR. Pronounced seasonality, fluctuations in nutrient quality, and variation of the grazing environment may contribute to the unexplained variation in specific growth.

Growth, Parr–Smolt Transformation, and Changes in Growth Hormone of Atlantic Salmon (Salmo salar) Reared under Different Photoperiods

Potential 1+ smolts of Atlantic salmon (Salmo salar) were reared under three light regimes: simulated natural photoperiod (LDN), continuous light (LD24:0), or a combination of continuous, low-intensity background light and a superimposed simulated natural photoperiod (dual photoperiod, LDD). Growth rate in freshwater was enhanced by LD24:0 and LDD, and changes associated with smoking (increased salinity tolerance, reduced condition coefficient) were advanced under LD24:0. Plasma growth hormone levels were initially high on LD24:0 and LDD whereas on LDN, plasma growth hormone levels increased gradually from February through April. Overall GH levels were negatively correlated with condition coefficient during the final stages of smoking. After 16 mo in seawater, there were no significant size differences among the groups. The incidence of sexual maturation as postsmolts was higher in the LD24:0 and LDD groups whereas the incidence of grilsing was higher in LDN. Results demonstrate the significant influence of photoperiod on growth and smoking in Atlantic salmon. An abrupt increase to continuous light in winter may be sufficient to advance important aspects of the parr–smolt transformation. Dual photoperiod may be a way to combine the increased growth rate observed under continuous light and the normal parr–smolt transformation associated with natural photoperiod.

Longevity, Body Size, and Growth in Anadromous Brown Trout (Salmo trutta)

Longevity in 25 populations of anadromous brown trout (Salmo trutta) showed a significant trend with increasing life span at latitudes of 58–70°N in Norway, with the largest change from 58 to 60°N. Moreover, longevity was negatively correlated with temperature and growth rate in freshwater and at sea. Body size was negatively correlated with water temperature and growth rate in freshwater, but not with latitude or water temperature and growth rate at sea. Thus, conditions influencing development and metabolic rates in fresh water seem more important than conditions in the sea in determining variation in longevity and body size of anadromous brown trout. Our results support the hypothesis that interpopulation variation in longevity and body size is influenced by rate of metabolism, chiefly influenced by ambient water temperature.

Development of seawater adaptation in juvenile steelhead trout ( Salmo gairdneri) and domesticated rainbow trout ( Salmo gairdneri)—Effects of size, temperature and photoperiod

As shown by repeated 96-h LC 50 tests, salinity tolerance increased continuously with increasing size in juvenile steelhead trout and domesticated rainbow trout. For both races salinity tolerance was highest at 11°C, lowest at 17°C and intermediate at 5°C. Small (7–15 g) steelhead and rainbow trout grew equally well at 14‰ and 19‰ salinity, while growth rate was reduced at 24‰ salinity. In steelhead trout exposure to constant 14.5-h daylength in January accelerated several changes associated with smoltification such as silvering, decrease in condition factor and increase in salinity tolerance compared to fish reared under 9.5-h daylength. Growth rate in fresh water and 29‰ sea water was not affected by photoperiod. In rainbow trout there was no significant photoperiodic effect on silvering, condition factor, salinity tolerance and seawater growth. Growth rate in fresh water was ca. 10% higher in the 9.5-h group than in the 14.5-h group.

Delayed photoperiod produces more uniform growth and greater seawater adaptability in underyearling coho salmon ( Oncorhynchus kisutch)

Coho fry were distributed among tanks in a factorial design of three temperatures (8, 11, and 14°C) by three photoperiod phases (natural, 1- and 2-month delayed) in February. Growth rate in fresh water was about 30% greater at 14°C than at 8°C. After 24 weeks of rearing, the coho on natural photoperiod at 14°C had separated into two distinct size modes; the lower mode contained fish smaller than 25 g and the upper mode contained fish larger than 35 g. At 8 and 11°C under natural photoperiod, the weight distributions were unimodal but were skewed toward larger sizes. In contrast, the weight distributions of fish under delayed photoperiod were much less variable and were not skewed. Periodic seawater challenge tests revealed a greater and more sustained seawater adaptability in coho reared under delayed photoperiod compared with natural photoperiod. Growth in sea water was assessed for groups of 50 fish transferred from 8°C fresh water to 12°C sea water in late July or August. Coho reared under delayed photoperiods grew about five times as fast in sea water as did those exposed to natural photoperiod. These results indicate that bimodal growth in juvenile salmon is a function of photoperiod phase at the time of first feeding and demonstrate the feasibility of producing underyearling coho smolts at temperatures as low as 8°C.

The enzyme gene variation of ten Finnish rainbow trout strains and the relation between growth rate and mean heterozygosity

The electrophoretic survey of 10 rainbow trout ( Salmo gairdneri Richardson) strains reared in Finland was made in connection with a simultaneous analysis of the growth rate of the strains. Five of the strains were from a State Fish Culture Station and the other five from commercial fish farms. Nine enzyme systems and 20 loci were examined. Eight loci were polymorphic. The genetic variation found was at about the same level as in earlier rainbow trout studies. Thus, Finnish rainbow trout strains have probably not lost much genetic variation since they were imported from the U.S.A. Genetically, the most distinct strain was the autumn spawning one. The genetic distances between the commercial strains were smaller than between the strains of the State Fish Culture Station. The genetic variation and the growth rate were greater in commercial strains than in the State strains, which have been kept more isolated from each other. In the nine spring spawning strains the correlation between the mean heterozygosity ( H) and average growth rate in sea water was 0.62, between H and growth rate in fresh water 0.59, and between H and the average weight 0.54. When only eight stocks of the same origin were included, the corresponding correlations were +0.83 ( P < 0.05), +0.70 ( P < 0.1) and +0.76 ( P < 0.05), and the correlation between H and the variation in weight was −0.66 ( P < 0.1).

The C-axis growth rate of ice crystals

An experimental investigation has been carried out into the C-axis growth rates of ice crystals growing from a capillary tip into a stream of brine or water inside a closely-controlled temperature bath. Results are reported for growth in water at flow velocities of 5 cm/s and 12.5 cm/s for bath sub-coolings ranging from 0.06 to 1.2 K. and for growth in brine of concentrations from 1 to 4% at a flow velocity of 5 cm/s for bath sub-coolings from 0.23 to 0.5 K. The fresh water growth rates are lower by an order of magnitude than earlier reported results at the same bath sub-coolings. The growth rates increase with stream velocity at high sub-coolings, suggesting boundary layer thermal resistance. When allowance is made for this effect, the growth rates plotted against surface sub-coolings are in closer agreement with the previously-reported data and confirm the two-dimensional nucleation mechanism. The salt water data indicate a decrease in C-axis growth rate with increase of salt concentration. At least part of this effect can be accounted for by salt build-up at the ice surface as the result of boundary layer diffusion effects.