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1.
Feed intake, specific growth rate and changes in body composition of age 1+ and 2+ Baltic salmon, Salmo salar L, were studied for fish held under constant temperature conditions. The 1+ fish (60 g) were reared for 6 weeks at 11, 15, 17, 19 or 23 °C and 2+ fish (250 g) were held at 15 °C. Feed intake of 1+ salmon increased from 176 kJ kg-1 day-1 at 11 °C to 275 kJ kg-1 day-1 at 17 °C and decreased to 229 kJ kg-1 day-1 at 23 °C. Specific growth rate increased from 1.18% day-1 at 11 °C to 1.59% day-1 at 15 °C and decreased to 0.56% day-1 at 23 °C. Optimum temperatures for feed intake and growth were estimated at 17.8 °C and 15.6 °C, respectively, and estimated upper thermal limits for feeding and growth were 29.0 °C and 24.1 °C, respectively. Models for feed intake and growth rate in relation to temperature and fish size are presented. The utilization efficiency of ingested energy decreased from 57% at 11 °C to 22% at 23 °C. For all groups of 1+ fish, most (approximately 86%) of the weight gain consisted of water. Lipid deposition accounted for about 52% of the body energy gain irrespective of rearing temperature.  相似文献   

2.
Sepiapharaonis, the pharaoh cuttlefish was cultured through multiplegenerations in the laboratory (5 consecutive generations) using closed,recirculating water filtration systems. The eggs of the original parentalgeneration (GP) were spawned by a wild caught Gulf of Thailandfemale in alocal fisheries laboratory, then packed and shipped air cargo to Texas wherehatching occurred. The culture temperature ranged 25°–28°C, except for one generation that was chilled intentionallyto21 °C and then warmed to 25 °C after 9.6months. Spawning occurred as early as day 161. Spawning output was high in allgenerations except the group that was cultured at 21 °C. Eggfertility was low in captivity (< 20%), but hatchling survival was high(>70%). The average egg incubation time was 13.6 d at 25–28°C. The largest spawn resulted in 600 viable hatchlings andthesmallest resulted in 11 hatchlings. The cuttlefish ate a wide variety ofestuarine crustaceans and fishes as well as frozen shrimp. There were noapparent disease problems since survival from hatching to maturity was over70%.The average life span for cuttlefish cultured at 25–28°Cwas 8.9 months and 12.3 months at 21 °C. Size at hatching wasmeasured for fourth generation (G4) hatchlings; the mean weight athatching was 0.103 g and the mean mantle length was 6.4mm. The largest cuttlefish cultured was a male 300 mmML and 3,045 g; the oldest cuttlefish lived 340 d.This cuttlefish species presents an excellent choice for commercial mariculturebecause of its rapid growth, short life span, tolerance to crowding andhandling, resistance to disease and feeding habits.  相似文献   

3.
Wild caught post-pueruli, year one and year two post settlement juvenile western rock lobster, Panulirus cygnus, were held at ambient temperatures (15.6 °C to 23.1 °C; mean 19.0 ± 0.07 °C) or at 23 °C, and fed the same ration of a formulated pellet diet either once per night, or 3 times per night, over 12 months, to determine whether elevated temperatures and multiple feeds per night would stimulate growth through increased metabolism and feed utilisation without significant negative impacts on survival. Survival of post-pueruli (mean 63%) did not differ between ambient and 23 °C. Survival of year 1 and 2 juveniles was higher at ambient temperatures (p < 0.01 ambient: year 1 juveniles, 68%; year 2 juveniles, 88%; 23 °C: 57% and 74%, respectively). Feeding frequency did not affect survival of post-pueruli and year 2 juveniles (mean 63%, 81% respectively), but survival was 9% higher for year 1 juveniles fed three times per night (58% versus 67%; p < 0.01). All lobsters grew faster at 23 °C than at ambient temperatures (p < 0.05), with the growth of post-pueruli almost doubled at 23 °C (weight gain at 23 °C versus ambient: post-pueruli, 18 438 % versus 9 915 %; year 1 juveniles 259% versus 165%; year 2 juveniles 23% versus 21%). Feed frequency did not influence the growth of year 1 and 2 juveniles. However, there was an interaction effect of temperature and feed frequency on post-pueruli where weight and carapace length were significantly higher at ambient temperatures when post-pueruli were fed three times a day, whereas at 23 °C weight and carapace length were significantly greater when fed once per day (p < 0.05). Feed intake (g pellet dry matter lobster− 1 day− 1) of pellet was higher at 23 °C for all lobsters (p < 0.05), but was the same between lobsters fed 3 times per night versus once per night. This study has shown that increasing temperatures to 23 °C significantly improved the growth of P. cygnus post-pueruli without any adverse effects on survival. The faster growth rates exhibited by year 1 and 2 juveniles at 23 °C may potentially offset their lower survival by significantly reducing culture period. There is no benefit of feeding P. cygnus multiple times at night in terms of growth and survival. The implications for P. cygnus culture are that temperatures should be maintained close to 23 °C during the entire growout period, with due care taken to minimise mortalities through adequate provision of food and shelter. Feeding P. cygnus once daily to excess just prior to dusk to co-incide with nocturnal feeding behaviour is recommended.  相似文献   

4.
Multiple regression analysis was used to develop mathematical models applicable to the growth and food intake of Octopus vulgaris. The variables considered were: body weight (Bw: 175–3,500 g), temperature (T: 13–28 °C), sex (S: male = 0, female = 1) and diet (D: bogue fish = 0, crabs = 1). Growth and food intake may be succesfully expressed by means of the following equations: Ln (AGR + 14) = –2.0135 + 0.0895 Ln Bw + 0.5087 T – 0.0142 T2 + 0.2997 D (R2 = 71.79; ANOVA p < 0.0001) and Ln (AFR) = – 5.6577 + 0.5137 Ln Bw + 0.5266 T – 0.0132 T2 + 1.1135 D (R2 = 78.71; ANOVA p < 0.0001), where AGR: absolute growth rate, AFR: absolute feeding rate, Bw: body weight, T: temperature and D: diet. In our experimental conditions, sex did not affect growth or food intake. The optimum temperature for growth (17.5 °C) and food intake (20 °C) was independent of body weight. Growth and food intake were higher with the crab diet. Nevertheless, food efficiency was better for animals fed on fish (bogue). Maximum food efficiency was reached at 16.5 °C for both diets. When the temperature was above 23 °C, weight losses and mortality were recorded; the temperature at which this occurred depending on body weight and diet, so that smaller and bogue-fed individuals were more sensitive to increasing temperatures. O. vulgaris growth may provide optimum economic performance from 16 to 21 °C. This range is too narrow, considering the wide natural range (12–29 °C) in some Mediterranean areas. Therefore, O. vulgaris growth will be limited by seasonality of temperature or must be carried out with other systems (e.g. recirculation in closed systems with temperature control) for it to be economically viable.  相似文献   

5.
Osteological malformations are always considered an important problem in intensive aquaculture. This work studies the effect of rearing temperature on malformations in sea bass, Dicentrarchus labrax. To this end, two batches of the species were subjected to the following incubation/cultivation temperatures: 15 °C/natural and 19/19 °C, from fertilization until 190 days after hatching. The different malformations were studied in 1643 juveniles at 190 days and classified by categories. The Chi-square statistic was calculated to verify the relationship between the presence of anomalies and the application of different temperatures. The percentage of anomalies observed in individuals reared at a high temperature (19/19 °C) was 66.44%. In both temperature systems, opercular malformations were those which caused a greater delay in growth. The results found indicated that temperature played a very important role in the development of deformations, which may be of interest from the viewpoint of aquaculture.  相似文献   

6.
Feed intake, specific growth rate and changes in body composition were studied in juvenile (140-170 g) Baltic salmon, Salmo salar, reared at three temperatures (2, 4 and 6 °C) under continuous light conditions. Feed intake increased from 20.4 kJ kg-1 day-1 at 2 °C to 63.8 kJ kg-1 day-1 at 6 °C, and growth rate increased from 0.10% day-1 to 0.37% day-1 over the same temperature interval. The estimated lower temperature limits for feeding and growth were approximately 0.35 °C and 0.6 °C, respectively. Amongst fish reared at 2 °C the majority (86%) of the weight gain consisted of water and protein, and these fish deposited very little lipid. Lipid deposition increased amongst the groups of fish held at the higher temperatures, and amongst the salmon reared at 6 °C lipid accounted for 43% of the body energy gain.  相似文献   

7.
Theeffect of temperature on scope for growth was determined in juveniles of thenorthern scallop Argopecten purpuratus (Lamarck, 1819).This economically important species, has been introduced into the south ofChilegiven that large-scale cultivation within the natural distribution zone islimited. Nevertheless, the lower water temperatures that exist in the southcould restrict the growth rate. No difference in the scope for growth wasdetected in specimens kept at 10 ± 1 °C and 18 ±1 °C and fed with a mixed diet 1:1 of Chaetocerosgracilis and Tetraselmis suecica. Temperaturedid not affect the quantity of energy derived from food ingested, but energyloss through respiration, faeces and excretion was greater at 10 ± 1°C than at 18 ± 1 °C. The resultsindicate that the growth rates of A. purpuratus aremaintained between 10 ± 1 °C and 18 ± 1°C, which would favour large-scale cultivation over a widelatitudinal range.  相似文献   

8.
Incubation of northern snake-necked turtle (Chelodina rugosa) eggs and subsequent sale of hatchlings for the pet industry has the potential to provide culturally suitable employment for indigenous communities in northern Australia. Developmental arrest in response to egg inundation is unique to C. rugosa. Eggs can be stored under water for up to 10 weeks without appreciable impact on egg or embryo survival, allowing the transport and sale of eggs into niche markets without high levels of mortality, and permitting eggs to accumulate in diapause until there are sufficient numbers to incubate as batches. Eggs that are not inundated or inundated for short periods experience similar survival rates to eggs inundated for lengthy periods. Incubation temperature influences embryo survival and development period in C. rugosa. Embryonic survival is greatest at 26 °C, steadily declining as temperature increases to 32 °C. A similar increase in incubation temperature decreases incubation period by approximately 40 days, however almost half of this variation is attributed to the increase in incubation temperature from 26 to 28 °C. Hatchling growth in C. rugosa is characterized by two phases. There is an initial phase of relatively slow growth under the partial influence of initial egg size and incubation duration, followed by a second phase of relatively rapid growth under the partial influence of water temperature and mass at hatching. Post-hatching survival is negatively correlated with duration of egg inundation and water temperature. Evidence suggests that inundation of C. rugosa eggs for 6 weeks, incubation of embryos at 28 °C and raising hatchlings in 28 °C water will yield the best overall outcomes.  相似文献   

9.
The influence of temperature on growth and biomass composition of two species of Spirulina, S. maxima and S. platensis used for food was studied. A 4L fermenter with temperature and agitation control was used to cultivate both species. Under continuous light, maximum cell production of 2.4 g l–1 was verified for both cultures studied at temperatures above 25 °C: S. maxima (30 °C and 35 °C) and S. platensis (25 °C and 30 °C). An accentuated lag phase was observed for all cultures at lower temperatures (15–20 °C), and a maximum biomass production of 1.5 g l–1 was achieved. It was also observed that an increase of temperature caused a marked decrease in protein content, while carbohydrate synthesis was stimulated. The concentration of -linolenic acid varied from 11–16% for S. maxima and from 12–14% for S. platensis, at the optimum growth temperatures. Greater culture volumes were also studied in order to compare the performance of glass and plastic containers. At optimum growth temperature, S. maxima produced the same cell growth and similar final biomass composition.  相似文献   

10.
Embryonic development of common wolffish (Anarhichas lupus L.) was studied at constant temperatures 5.0, 7.0, 9.0, 11.0, 13.0 and 15.0°C. Duration of development from egg activation to several morphological stages including 50% hatching was determined. At 5.0–11.0°C, the survival rate of eggs to hatching ranged from 51 to 88% with a tendency to increase at 5.0 and 7.0°C. Morphological anomalies, bacterial contamination and large mortalities were observed in eggs incubated at 13.0 and 15.0°C. The period of hatching lasted from 10 to 50 d in different egg groups. Embryo length and yolk sac volume at identical morphological stages of development showed only slight relation to temperature. At lower temperatures newly hatched larvae were longer and at more advanced stages of ontogeny. Normal numbers of fin rays in larvae (mean values 74 for dorsal fin and 46 for anal fin) were observed at 5.0 and 7.0°C and in most larvae at 9.0°C. At 11.0 and 13.0°C, many rays were absent, with mean values for dorsal fin 60 and 39 respectively and for anal fin 28 and 4 respectively. The approximate upper limit for normal development of fin rays appeared to be 9.0 °C.  相似文献   

11.
Eggs of spotted wolffish (Anarhichas minor Olafsen)were incubated at constant 4, 6 and 8 °C, and disinfected withglutaric dialdehyde (150 p.p.m. for 5 min) once ortwice a month during two thirds of the incubation period, to prevent growth ofmicroorganisms. Hatching of apparently normal larvae started earlier when eggswere disinfected twice a month compared to once a month at all incubationtemperature regimes. The time to 50% hatch was 900 and 920 day-degrees (16 and16,5 weeks) at 8 °C, 835 and 880 day-degrees (20 and 21 weeks)at 6 °C and 725 and 800 day-degrees (26 and 28,5 weeks) at 4°C, in the egg groups disinfected twice or once a month,respectively. The best survival until hatching was noted when eggs weredisinfected twice a month and incubated at 6 and 8 °C.Survivalwas very low at 4 °C. Prematurely hatched larvae wereregistered in all egg groups disinfected twice a month and the highestfrequencywas noted in the 8 °C groups. The larval weight at normalhatching in the 6 and 8 °C groups was negatively correlatedwith incubation temperature and intervals of disinfection during the incubationperiod, but after 42 days feeding with live feed (unenrichedArtemia) the weights of the larvae were not significantlydifferent. The specific growth rates of the larvae from the eggs incubated at 6°C and 8 °C were 3.0% and 3.2%, respectively.The mean survival of larvae was between 88% and 96% at 42 days post-hatching.Young wolffish originating from the 6 °C incubation groupsshowed lowest mortality.  相似文献   

12.
This study aimed to evaluate the effect of temperature and dietary starch level on growth performance, nutrient utilisation, whole-body composition and activity of selected hepatic intermediary metabolism enzymes in European sea bass juveniles. An experimental diet was formulated to contain 46% crude protein, 12% crude lipids and 30% pregelatinized starch (diet 30GS); two other diets were formulated to include the same levels of all ingredients as diet 30GS except for the pregelatinized starch, which was included at 20% (diet 20GS) or 10% (diet 10GS). Diets were assigned to triplicate groups of 25 fish (initial weight: 15 g) at two water temperatures (18 and 25 °C) for 10 weeks. Group receiving diet 30GS was fed to apparent satiation and groups fed diets 20GS and 10GS were pair-fed according to group fed diet 30GS, so that each group ate the same amount of all nutrients except for carbohydrates. At the end of the trial, growth rate, feed efficiency and protein efficiency ratio were higher at 25 than at 18 °C. Dietary starch level did not affect growth or N utilisation. Feed efficiency was inversely related to dietary starch level. Whole-body lipids and energy content were higher at 25 °C and increased with dietary starch levels. Whole-body protein and ash content were also higher at 25 °C but were not affected by dietary starch level. Liver glycogen, HSI and VI increased with dietary starch level. ADC of starch was higher at 25 °C and within each temperature decreased with increasing dietary starch levels. ADC of protein was neither affected by temperature nor dietary starch levels. Data on enzyme activities showed that hexokinase (HK) but not glucokinase (GK) was affected by temperature. Dietary starch level affected the activities of glucokinase and glucose-6-phosphate dehydrogenase (G6PD) but not of the others enzymes tested (HK, PK, FBPase and GDH).  相似文献   

13.
Hatching and start-feeding temperatures affected the expression of different trypsin isozymes in the pyloric caeca of Atlantic salmon. Hatching temperature of 10 °C induced the expression of the common isozyme TRP-2*100, and of 6 °C induced the variant TRP-2*92 (p$<$0.01). In contrast, start-feeding temperature of 12 °C significantly (p$<$0.0001) influenced the expression of the variant TRP-2*92, compared to 6 °C. The frequencies between different trypsin isozyme patterns were not changed at later stages under varied rearing temperatures.The frequency distribution between Atlantic salmon without and with trypsin variants was about 0.4:0.6. The trypsin isozyme TRP-2*92 was the major variant in Norwegian salmon, while the trypsin variant TRP-1*91 was dominant in Scottish salmon, at frequencies of 0.47 and 0.42, respectively. The presence of both the common and either variant trypsin isozymes were important for feed utilization and growth at varying rearing temperatures. Trypsin isozymes are functionally sensitive to different temperatures. The expression of the common trypsin isozyme TRP-2*100 is important when the water temperature is $>$ 8 °C, while it is important for the expression of the variant TRP-2*92 when the water temperature is $\leq$ 8 °C, especially below 6 °C. The variant TRP-1*91 was observed to perform effectively at a wider temperature range than the variant TRP-2*92, but not at temperature $\leq$ 6 °C.Genetic variation in trypsin isozyme pattern is a primary factor affecting food conversion efficiency and growth under different rearing temperatures.  相似文献   

14.
The activity of the enzyme Na+,K+-ATPase and morphological changes of gill chloride cells in grouper, Epinephelus coioides larvae and juveniles were determined 6–48 h after abrupt transfer from ambient rearing conditions (30–32 ppt, 26.5–30 °C) to different salinity (8, 18, 32, 40 ppt) and temperature (25, 30 °C) combinations. Na+,K+-ATPase activity in day 20 larvae did not change at salinities 8–32 ppt. Activity decreased significantly (P <0.01) after exposure to 40 ppt at 25–30 °C, which was accompanied by an increase (P <0.05) in density and fractional area of chloride cells. Enzyme activity in 40 ppt did not reach a stable level and larvae failed to recover from an osmotic imbalance that produced a low survival at 25 °C and death of all larvae at 30 °C. Enzyme activity and chloride cell morphology in day 40 groupers did not change in 8–40 ppt at 25 °C and 8–32 ppt at 30 °C. A significant decrease and a subsequent increase in Na+,K+-ATPase activity in 40 ppt at 30 °C was associated with the increase in chloride cell density resulting in an increased fractional area but a decreased cell size. Enzyme activity and chloride cells of day 60 grouper were unaffected by abrupt transfer to test salinities and temperatures. These results demonstrate that grouper larvae and juveniles are efficient osmoregulators over a wide range of salinities. Salinity adaptation showed an ontogenetic shift as the larvae grew and reached the juvenile stage. This development of tolerance limits may reflect their response to actual conditions existing in the natural environment.  相似文献   

15.
Scallop spat production normally requires transfer between growthsystems. Simulated transport experiments were carried out in April, June,December and February to evaluate effects of transport time on greatscallop (Pecten maximus) spat growth and survival. The spat (1.7–1.8 mm in shell-height and 21–25 µg ash free dry weight [AFDW]) wereheld in moist coffee filters at a temperature of 10 °C for up to 24 h,before being replaced into sieves in rearing tanks at 15 °C. The studyshowed that by increasing air emersion time, survival and growthdecreased. No significant difference in the results between 0 and 4 h of airemersion was found, while the effects after 12 and 24 h differed betweenspat groups. Survival and growth rates showed seasonal differences. Meansurvival was 35–71% in April and 77–99% from June to February. In Junemean growth rates attained were 115–128 µm shell-height and 15–18µg AFDW per day compared with 49–69 µm and 3.8–7.0 µgper day for the other spat groups. Great scallop spat may survive atransfer time of 24 h, but transportation for longer than 12 h is notrecommended if subsequent high survival and growth rates are to beensured.  相似文献   

16.

Offshore migration of Pacific salmon Oncorhynchus spp. is partly triggered by increasing body size and high motility in the early stages of life. The survival of juvenile salmon may depend on their growth rate during the first few months in the sea, and this factor partly regulates the dynamics of adult populations. Here, we assessed the effects of water temperature and food availability on the growth of juvenile chum salmon O. keta. In addition, by combining the measurements of metabolic performance for growth and activity (Absolute Aerobic Scope: AAS) with a bioenergetics model, we estimated the energy allocation for different activities in the juveniles. Under high temperatures (14 °C), juveniles reared at low food levels (1% body weight) allocated less than half their energy for growth than those reared at high food levels (4% body weight). These findings suggest that high temperature and low food level constrain the growth of juveniles, providing an insight into the effect of the recent increase in warm and low-nutrient water masses on survival of juveniles and catches of adult chum salmon on the Pacific side of Honshu Island, Japan.

  相似文献   

17.
Studies were conducted to determine the effect of water hardness onClarias gariepinus egg hatchability and larval viability.The fertilized eggs were incubated at 28 °C and with waterhardnesses ranging from 10–700 mg/l CaCO3. Themean hatching rate fluctuated between 42.31% at hardness of 10mg/land 64.66% at 2000 mg/l. Abnormalities in the larvae were observedbeyond 200 mg/l and increased with increase in water hardness. Thehighest larval survival of 71.05% was recorded at 60 mg/l waterhardness. Based on statistics performed with analysis of variance (ANOVA) andfurther compared with Duncan's multiple range test (p = 0.05), the resultsimplythat very soft water (0–10 mg/l) and very hard water (300mg/l and above) are not suitable for Clariasegg incubation and larval rearing. A water hardness of 30–60mg/l CaCO3 is recommended for optimal normal hatching,high viability and maximum larval development of Clariasgariepinus.  相似文献   

18.
Although thermal influences on the physiology of rainbow trout (Oncorhynchus mykiss) have been widely studied, there is little information about the responses of different genetic strains to temperatures. The effects of water temperature (10, 14, 19, 22, and 25 °C) on food consumption rate, growth rate, gross conversion efficiency, resting routine oxygen consumption rate, upper critical thermal tolerance and critical swimming velocity were investigated in juvenile rainbow trout of the Eagle Lake (O. m. aquilarum) subspecies and the Mt. Shasta strain. No strain-related differences in conversion efficiency, oxygen consumption rates, thermal tolerance or swimming performance were observed in 1995 (19, 22, and 25 °C) or 1996 (10, 14, and 19 °C), but Mt. Shasta strain trout grew faster at highest temperatures than did Eagle Lake trout. Food consumption rates, growth rates, conversion efficiency, and oxygen consumption rates declined at the extreme temperatures (10 and 25 °C) in both Eagle Lake and Mt. Shasta trout. Swimming performance was temperature-independent between 10 and 19 °C (overall mean: 5.43 body lengths s–1).  相似文献   

19.
To determine whether the embryonic period of channel catfish lctalurus punctatus could be extended at low temperatures, fertilized channel catfish eggs were incubated at five constant water temperatures: 4, 11. 16. 21, and 26 C. Low-temperature incubation of catfish eggs extended the embryonic period at 16 (244%) and 21 C (56%) when compared to the control hatchery incubation temperature of 26 C. All eggs incubated at 4 and 11 C died within 24–48 h. Developmental stage had a significant ( P > 0.05) effect on percent hatch at 16, 21, and 26 C. Eggs held at 16 C prior to embryonic axis formation died within 48 h. Larvae from eggs hatched at 16 C were incompletely developed and died upon acclimation to 26 C for growth tests. Growth of fry reared at 26 C, following egg incubation at 21 C. paralleled that of fry from eggs incubated at 26 C. The underdevelopment of fry at 16 C combined with the significant effect of egg stage on survival at this temperature suggests that 16 C is below the lower thermal tolerance limit for normal development in this species. The period prior to the formation of the embryonic axis may be considered a vulnerable stage in channel catfish development. Increasing the embryonic period through low temperature incubation would increase the duration of juvenile availability for researchers and commercial operations.  相似文献   

20.
We studied the growth properties of three different hemoglobin genotypes of juvenile turbot (Scophthalmus maximus) reared at 10, 14, 18 and 22 °C. The genotype Hb-I(2/2) displayed the overall highest growth rate in the temperature range 14–22 °C, whereas no differences were found at sub-optimal temperature (10 °C). The differences in growth were largest at optimal temperatures where the Hb-I(2/2) genotype displayed 13% higher growth than the two other genotypes. Optimal temperature for growth (T opt.G) varied between the genotypes with the genotype Hb-I(2/2) displaying the highest T opt.G (23.0 °C) and Hb-I(1/1) the lowest (19.0 °C). The biological significance of this link between biochemical genetic variation and physiological properties might be influences on growth pattern, ultimate size and age at first maturity. This is the first reported quantitative trait locus (QTL) for this species.  相似文献   

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