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1.
A field campaign was conducted around salmon cages, using a combination of a towed ADCP and a free‐fall multi‐parameter profiler, in order to investigate flow structures and the possible distribution of effluent materials. Two transect observations showed that hydrographic conditions changed dramatically within 5 days, from highly stratified open water conditions to weak stratification. Three‐dimensional observation revealed that flow was blocked behind the cages and that the blockage was reduced as the distance from the cages increased. The flow speed was positively correlated with the intensity of the backscattering signal. The R2 value was high immediately behind the cages and decreased with distance from the cages. The flow time series behind the cages exhibited a k–2 power law spectrum that was consistent with a typical internal wave spectrum. This suggests that eddies shed from the cages were highly influenced by stratification. We estimated the rate of kinetic energy dissipation, , from YODA Profiler data based on the Thorpe scale approach. We also estimated the eddy diffusivity coefficient, . Both and followed a lognormal probability density function. The mean was consistent with a one‐dimensional diffusion model assessed from the R2 values of flow speed and backscatter intensity.  相似文献   

2.
A novel marine origin Bacillus subtilis strain H1 isolated from a shrimp culture pond effectively removed NH4+‐N, ‐N and ‐N, with a maximum ammonium, nitrite and nitrate removal rate of 2.35 mg NH4+‐N L?1 hr?1 per OD, 9.64 mg ‐N L?1 hr?1 per OD and 0.75 mg ‐N L?1 hr?1 respectively. The gas chromatography–isotope ratio mass spectrometry results indicated that N2O was emitted when 15NH4Cl, Na15NO2 or Na15NO3 was used. Additionally, N2 was also produced when Na15NO2 was used. Single‐factor experiments suggested that the optimal conditions for NH4+‐N and ‐N removal were glucose as a carbon source, C/N 15, initial pH 7.5, 30 g/L NaCl, 28°C and a shaking speed of 160 rpm. Orthogonal tests showed that the optimal conditions for NH4+‐N removal were C/N 15, pH 9, 10 g/L NaCl and shaking speed 160 rpm when ammonium chloride was used as the substrate. The optimal conditions for ‐N removal were C/N 10, pH 6, 10 g/L NaCl and a shaking speed of 160 rpm when sodium nitrite was used as the substrate. In summary, B. subtilis strain H1 had highly efficient aerobic nitrifying–denitrifying ability and high adaptability, suggesting that it is potentially valuable to marine aquaculture.  相似文献   

3.
Studies on chronic or acute toxicity of nitrogen species on fish in recirculating aquaculture systems (RAS) usually focused on adverse effects of total ammonia nitrogen (TAN: sum of NH3 + NH4+) and nitrite (), while underestimating the potential effects of high nitrate accumulation on growth and health status of fish. In our study, Nile tilapia (Oreochromis niloticus) were exposed to five different nitrate concentrations (0, 10, 100, 500 and 1000 mg L?1 ‐N) over 30 days. Growth parameters (feed conversion ratio (FCR), specific growth rate (SGR), hepatosomatic index (HSI)), blood samples (concentrations of haemoglobin, methaemoglobin, plasma /) and the histology of the gills were studied to evaluate growth and health status of the fish. At the highest nitrate concentration, the fish showed significantly reduced growth and impaired health status (SGR, FCR, plasma /, haemoglobin and methaemoglobin concentration), demonstrating that too high nitrate concentrations can negatively influence tilapia production in RAS. Here, we recommend not exceeding concentrations of 500 mg L?1 ‐N in juvenile tilapia culture to ensure an optimal health and growth status of the fish, as below that concentration no effects on the tilapia have been observed.  相似文献   

4.
Herbivorous fish can have strong effects on stream ecosystem function by consuming primary producers and excreting limiting nutrients, but it is unclear whether they are resource limited. Thus, understanding factors regulating abundance of these fish might help predict ecosystem function. We used stream mesocosms to test whether populations of central stoneroller Campostoma anomalum exhibit density dependence across a range of typical densities and resource abundance found in Great Plains streams. We predicted that incrementally increasing stocking biomass from 3·7 to 24·9 g·m?2 would reduce standing stocks of resources resulting in lower growth of stocked fish. Fish growth (over 41 days) was compared to initial stocking biomass and primary production as well as standing stocks of algae and invertebrates using regression analysis. Mean growth of individuals was negatively associated with stocking biomass ( = 0·55; P = 0·02), as predicted. Contrary to our prediction, increases in fish biomass led to increased primary productivity ( = 0·31, P = 0·07), but resulted in no relationship among algal filament lengths ( = 0·00; P = 0·34), algal biomass ( = 0·12; P = 0·19) or invertebrate biomass ( = 0·03; P = 0·30). Thus, density dependence occurred without an apparent reduction in food resources. We hypothesised that stoneroller growth was possibly limited by competition for high‐quality algae or invertebrates, or behavioural interactions causing interference competition.  相似文献   

5.
The Channel Catfish Ictalurus punctatus is an important ecological, recreational and aquaculture species. In both natural and pond culture systems, Channel Catfish are periodically exposed to acute increase in temperature, especially in the summer, which may induce a stress response. With the effects of global climate change, the impact of rising temperatures on aquatic systems is expected to be exacerbated in the future. Hence, there is the need to understand the physiological mechanisms controlling the thermal stress response in fish. Acid–base, haematological, osmotic and metabolic regulations were investigated following acute temperature increase from 28°C to either 32°C or 36°C at a rate of 2°C/hr to assess the physiological response of Channel Catfish to temperature increase. Blood was sampled 1 hr after treatment temperatures were reached. When temperature increased from 28 to 32°C, blood bicarbonate () decreased while cortisol, partial pressure of carbon dioxide (pCO2) and glucose increased. When temperature increased from 28 to 36°C, blood pH, , chloride, total proteins and mean corpuscular haemoglobin concentration decreased while cortisol, pCO2, haematocrit, haemoglobin, glucose, lactate, mean corpuscular volume and mean corpuscular haemoglobin all increased. The changes observed are characteristic of acute stress responses in fish and suggest that acute temperature increases to both 32 and 36°C are physiologically stressful to Channel Catfish.  相似文献   

6.
Arctic charr, Salvelinus alpinus, were obtained as eggs from two North American sources, an eastern (Fraser River, Canada) and a western (Bristol Bay, Alaska, USA) stock. Fish were pit tagged (eastern , western ) and stocked communally into three replicated 7‐m3 tanks at a density of 7.6 ± 1.2 kg/m3. Each tank was supplied with 2 ppt salinity water from a recirculating biological filtration system. Fish were fed a commercial diet (48%P, 20%F) from automatic feeders. Fish were harvested approximately 24 mo after hatching at a final tank density of 56.2 ± 1.3 kg/m3. Mean daily water temperature was 10.4 C with a range of 5.9–12.6 C and mean dissolved oxygen was 12.6 mg/L with a range of 9.7 (91% of saturation) to 17.8 mg/L (149% of saturation). Individual fish were evaluated for total, carcass, and fillet weight, sex, stage of sexual maturity, fillet fat, fillet color, and gonad weight. The western stock fish grew faster and were significantly larger ( ) (P < 0.0001) than the eastern stock ( ). Heritabilities were low for all traits and ranged from 0.08 ± 0.06 to 0.28 ± 0.09. Genetic correlations for body size traits were highly positive and significant (0.99–1.00). Genetic correlations of fillet color and body size traits were positive, but not significant. Genetic correlations of fillet fat with body size traits were negative, but not significant. Genetic correlation of fillet fat and fillet color was positive and significant (0.55 ± 0.27). Random genetic variation was assessed from microsatellite variability on 30 fish from each stock (eastern and western) and 32 fish from a third commercial source of unknown origin for comparison. The amount of variation detected in the western stock was higher than the eastern and commercial stocks. The eastern stock was composed of an admixture of two sources, the commercial stock was composed by three different sources, and the western stock was composed by three to four source populations. Data will be used to calculate breeding values on a separate group of captive sibling adult broodfish and a line selected for carcass weight and maturity at 3 yr will be developed.  相似文献   

7.
  1. Arapaima (Arapaima sp.) are highly overexploited fish endemic to the Amazon basin. Because the fish are obligate air-breathers, it is possible to use surface-breathing events to count individuals visually for population censuses important for conservation, yet uncertainties remain about body size and environmental influences on air-breathing intervals, and thus count accuracy.
  2. This study examined relationships between breathing intervals and environmental parameters (e.g. water temperature and transparency) and body size for radio-tagged arapaima (n = 12) in an upland river-floodplain (Lake Ayapuá, Amazonas, Brazil). Generalized additive mixed models were used to evaluate environmental, size, and behavioural correlates of breathing intervals.
  3. Temperature was the most influential predictor of air-breathing intervals, followed by body size. The shortest breathing intervals were associated with consecutive ‘aggressive’ breaths while the longest breathing intervals had consecutive ‘calm’ breaths. Type of breath, size, and temperature predictors revealed that breathing intervals ranged from 4 to 46 min and were not significantly different among life stages (  = 15.9 min for sub-adults and adults (>1 m);  = 14.8 min for juveniles (<1 m)).
  4. Whereas the current population census method uses fish counts in 20-min intervals, this study found that 15% of observed breaths, and two thirds of fish, took longer than 20 min to breathe. These findings were obtained in relatively cool-water environments, so it is recommended that future population census methods consider water temperature (e.g. extend intervals used for counts in cooler waters), which may improve the accuracy of census counts and thus further enhance arapaima conservation efforts.
  5. This study demonstrated an effective method in which fundamental biological information is used to inform and improve population census methods for an imperilled fish in a region where traditional stock assessment is ineffective. Similar approaches for adaptive stock assessments could be applied to improve conservation of other air-breathing fishes (e.g. lungfishes) globally.
  相似文献   

8.
The aim of this study was to estimate heterosis and heritability for harvest body weight of the Pacific white shrimp (Litopenaeus vannamei) measured at commercial farm conditions. Heterosis and heritability were estimated using a base population from diallel crosses of eight introduced strains. The base population included 9936 shrimp from 207 families that were produced with 188 sires and 172 dams using a nested mating design by artificial insemination. Heterosis was calculated basing on the least squares means (LSM) of harvest body weight. The results showed that most of the hybrids (75%) have positive heterosis for harvest body weight, which ranged from ?13.36% (UA2 × UA5) to 13.80% (UA6 × UA5) with a mean of 2.41%. The high amount of heterosis manifested in the hybrids indicated the usefulness of these hybrids for improving the growth. Variance components and heritability for harvest body weight were estimated using an animal model. The heritability estimate for harvest body weight was 0.092 ± 0.082 (h2) when genetic groups were excluded from the pedigree, but it was decreased when genetic groups were included in the pedigree ( = 0.066 ± 0.050), implying that there are strain additive genetic effect and heterosis in the base population. However, the heritability estimates for harvest body weight were significantly different from zero (P < 0.05) and there was no significant difference between h2 and (P > 0.05). The results from this study indicated that significant improvement for growth is possible through cross‐breeding and selective breeding in L. vannamei.  相似文献   

9.
Fisheries scientists use biological models to determine sustainable fishing rates and forecast future dynamics. These models require both life‐history parameters (mortality, maturity, growth) and stock‐recruit parameters (juvenile production). However, there has been little research to simultaneously predict life‐history and stock‐recruit parameters. I develop the first data‐integrated life‐history model, which extends a simple model of evolutionary dynamics to field measurements of life‐history parameters as well as historical records of spawning output and subsequent recruitment. This evolutionary model predicts recruitment productivity (steepness) and variability (variance and autocorrelation in recruitment deviations) as well as mortality, maturity, growth, and size, and uses these to predict intrinsic growth rate (r) for all described fishes. The model confirms previous analysis showing little correlation between steepness and either natural mortality or asymptotic maximum size (). However, it does reveal taxonomic patterns, where family Sebastidae has lower steepness () and Salmonidae has elevated steepness () relative to the prediction for bony fishes (class Actinopterygii, ). Similarly, genus Sebastes has growth rate (0.09) approaching that of several shark families (Lamniformes: 0.02; Carcharhiniformes: 0.02). A cross‐validation experiment confirms that the model is accurate, explains a substantial portion of variance (32%–67%), but generates standard errors that are somewhat too small. Predictive intervals are tighter for species than for higher‐level organizations (e.g. families), and predictions (including intervals) are available for all fishes worldwide in R package FishLife. I conclude by outlining how multivariate predictions of life‐history and stock‐recruit parameters could be useful for stock assessment, decision theory, ensemble modelling and strategic management.  相似文献   

10.
This study established a pilot‐scale recirculating treatment system that coupled an ecological process with a biological process to achieve adequate water quality and to minimize the water consumption for intensive marine culture. The recirculating treatment system consisted of a settling cell, a biofilter tank, a bivalve tank and gravel beds. The toxic pollutants, threatening the growth of bivalves, were reduced by the settling cell and the biofilter tank, so that the polyculture of shrimp and bivalves could be achieved. The living bivalve tank could function well as a remover of remaining small suspended solids (SS), and other pollutants. As the SS was reduced to a very low level by bivalve tank before the water flowing into the gravel beds, the risk of clogging was prevented. The studies suggested that the system maintained high removal efficiencies of SS, ammonium nitrogen () and nitrite nitrogen () and could contribute to the increase in shrimp yield.  相似文献   

11.
Optimum manure rate in horizontally-integrated fish ponds, using poultry droppings, was evaluated in two agricultural zones of Imo state of Nigeria between July 1994 and January 1995. It was aimed at resolving the problem of frequent cases of excessive algal blooms, oxygen depletion and stress-related mortalities in fish ponds. Results indicate that poultry droppings, applied at the rate of 5000 kg ha?1 per year gave the best yield (23.5 M.t ha?1 for Heterobranchus bidorsalis Geofrey St Hillaire, 1809; and 11.2 tons ha?1 for Oreochromis niloticus Linnaeus, 1758), higher fish recovery and optimum tolerance levels of the physico-chemical parameters of water for fish growth. The estimated costs of production at this level of fertilization were 2 734 000.00 per hectare (equivalent to US$33 351.5), with the highest net revenue of 1 555 000.00 (US$18 963), and a cost: benefit ratio of 1: 2.3. This implies that for every 1.00 (US$0.01) invested in the production system at this rate of pond fertilization, the highest net profit of 1.30 (US$0.02) accrued to the farmer compared with any other manure load of the pond.  相似文献   

12.
Nitrogen and Phosphorus are the major end products of fish feed loading and affect the water environment as a whole. A magnetic stirrer was used to simulate the intensity of water flow by using different stirring strengths (0, 600, 1,200 rpm), and kinetic experiments on nutrients release from different fish feed (0.2500 and 0.5000 g) were performed. Results have shown that total phosphorus (TP) increase rapidly and become stable in about 96 hr, while orthophosphate ( ), total nitrogen (TN) and ammonia nitrogen ( ) increase relatively slowly and gradually reach stable from 200, 300 and 300 hr respectively. Both released contents of unit weight fish feed (i.e. released nutrients contents) and released nutrients concentrations in the condition of stirring were higher than those in the static condition. All of the pseudo‐first‐order, pseudo‐second‐order and Elovich kinetic models can be used to describe variations of released TP, , TN and contents with time, while the pseudo‐first‐order kinetic and Elovich kinetic models give better results with R2 = .66–.99 and R2 = .57–.99 respectively. Variance analysis showed that both stirring strength and fish feed type have significant effects on released TP, TN and contents (p < .05), while fish feed dosage has no significant effects (p > .05). In addition, only the fish feed type does have significant effects on contents (p < .05). In sum, the release kinetics and the factors related to the release of nutrients from fish feed are essential in planning strategies of nutrient management and pollution control.  相似文献   

13.
The pharmacokinetic of minocycline was studied after a single intravenous as well as oral dose (5 mg/kg body weight) in crucian carp (Carassius auratus) reared in freshwater at 10°C. Plasma samples were randomly collected from six fish at each sampling time. Plasma concentrations were determined by high‐performance liquid chromatography and further subjected to noncompartmental analysis. Initial concentration of minocycline just after intravenous administration was calculated as 7.320 μg/ml, while the other parameters after intravenous injection were determined as flows: apparent elimination rate constant (λz) of 0.064 per hr, apparent elimination half‐life () of 10.82 hr, total body clearance (Cl) of 142.72 ml/hr/kg, volume of distribution (Vz) of 2,227.38 ml/kg and volume of distribution at steady‐state (Vss) of 1,937.08 ml/kg. While after oral administration, the λz, , mean absorption time (MAT), absorption half‐life (t1/2ka) and bioavailability were determined as 0.059 per hr, 11.74, 5.55, 3.84 hr, and 81.98%, respectively, and the peak concentration was observed as 1.474 ± 0.362 μg/ml at 8 hr. It was shown that minocycline was slowly but relatively completely absorbed, extensively distributed, and slowly eliminated in crucian carp. Based on the ratios of AUC0–24 hr/MIC90, a minocycline dosage of 5 mg/kg body weight administered intravenously or orally would be only effective to successfully treat crucian carp infected by bacterium with MIC values ≤0.25 μg/ml.  相似文献   

14.
Burbot, Lota lota (L.), populations are declining throughout much of their native distribution. Although numerous aspects of burbot ecology are well understood, less is known about effective sampling techniques for burbot in lotic systems. Occupancy models were used to estimate the probability of detection () for three gears (6.4‐ and 19‐mm bar mesh hoop nets, night electric fishing), within the context of various habitat characteristics. During the summer, night electric fishing had the highest estimated detection probability for both juvenile (, 95% C.I.; 0.35, 0.26–0.46) and adult (0.30, 0.20–0.41) burbot. However, small‐mesh hoop nets (6.4‐mm bar mesh) had similar detection probabilities to night electric fishing for both juvenile (0.26, 0.17–0.36) and adult (0.27, 0.18–0.39) burbot during the summer. In autumn, a similar overlap between detection probabilities was observed for juvenile and adult burbot. Small‐mesh hoop nets had the highest estimated probability of detection for both juvenile and adult burbot (0.46, 0.33–0.59), whereas night electric fishing had a detection probability of 0.39 (0.28–0.52) for juvenile and adult burbot. By using detection probabilities to compare gears, the most effective sampling technique can be identified, leading to increased species detections and more effective management of burbot.  相似文献   

15.
A physiological study was performed to explore the effects in Sphoeroides annulatus (Jenyns 1842) juveniles of exposure to different salinities 10, 17, 23, 29, 35 and 41‰ on oxygen consumption rate (OCR), ammonium excretion rate (AER), the oxygen‐nitrogen atomic ratio (O:N), osmoregulation and Na+/K+‐ATPase expression. The OCR values ranged from 27.9 to 30.9 mg O2 h?1 kg?1, displaying a Type 1 response pattern Kinne (1977). AER ranged from 0.60 to 0.69 mg h?1 kg?1, and O:N values were from 53.12 to 59.26, indicating that the puffers use proteins and lipids as an energy‐substrate. Osmoregulation in S. annulatus was hyposmotic in salinities of 23, 29, 35 and 41‰ and hyperosmotic in a salinity of 10‰. The isosmotic point of the bullseye puffer was 356 mmol kg?1 (10.5‰). The enzyme expression analysis indicates that the fish acclimated to 41‰ had the highest Na+/K+‐ATPase expression level, whereas, the lowest expression level was found close to the isosmotic point. Na+/K+‐ATPase expression in the gills was found to have a U‐shaped relationship with environmental salinity. We conclude that the bullseye puffer is strongly euryhaline and can be cultivated in a wide range of environments that has important economic implications.  相似文献   

16.
Nan Bai  Min Gu 《Aquaculture Research》2017,48(4):1856-1865
This study investigated the attenuate effects of zinc (Zn) and selenium (Se) on lipopolysaccharide (LPS)‐induced oxidative stress in sea cucumber Apostichopus japonicus coelomocytes in vitro. Coelomocytes were first treated with different concentrations of Zn (0.12, 0.48 and 1.2 mM) and Se (0.06, 0.24 and 0.6 mM) for 12 h and the optimal concentrations of Zn and Se as antioxidants for A. japonicus coelomocytes were selected based on antioxidant parameters including total antioxidant capacity (T‐AOC) and activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione‐S‐transferase (GST) and concentration of reduced glutathione (GSH). Next, coelomocytes were pretreated with 0 (control), 0.12 mM Zn or 0.24 mM Se for 12 h, and then were treated with LPS (100 μg mL?1) for 6 h. Se completely inhibited LPS‐induced increase in superoxide anion () production and lipid peroxidation (LPO) and effectively prevented the LPS‐induced decreases of T‐AOC, activities of SOD, CAT, GPx and GST and concentration of GSH. Zn alleviated the LPS‐induced oxidative stress but the protective effects were not as effective as Se. The present work also proved that suboptimal amount of Zn and Se could impair the antioxidant system of A. japonicus coelomoytes. In conclusion, the present work demonstrated that both Zn and Se, especially Se, have the potentials to be the effective antioxidants for A. japonicus. Further work will be conducted for their optimal administration concentrations in vivo.  相似文献   

17.
We revisit the empirical equation of Gislason et al. (2010, Fish and Fisheries 11 :149–158) for predicting natural mortality (M, year?1) of marine fish. We show it to be equivalent to , where L∞ (cm) and K (year?1) are the von Bertalanffy growth equation (VBGE) parameters, and L (cm) is fish length along the growth trajectory within the species. We then interpret K in terms of the VBGE in mass , and show that the previous equation is itself equivalent to a ?? power function rule between M and the mass at first reproduction (Wα); this new ?? power function emerges directly from the life history that maximizes Darwinian fitness in non‐growing populations. We merge this M, Wα power function with other power functions to produce general across‐species scaling rules for yearly reproductive allocation, reproductive effort and age at first reproduction in fish. We then suggest a new way to classify habitats (or lifestyles) as to the life histories they should contain, and we contrast our scheme with the widely used Winemiller–Rose fish lifestyle classification.  相似文献   

18.
Hypnea musciformis that are harvested from natural beds and introduced Kappaphycus alvarezii are the two main sources of raw material for the production of carrageenan in Brazil. The daily growth rate (DGR) and carrageenan yield (CY) of both species were evaluated in vitro and in the sea to assess the feasibility of cultivating H. musciformis as a complement or as an alternative to the production of K. alvarezii. The DGR of H. musciformis (10.8 ± 0.6% day?1) was higher than the DGR of K. alvarezii (5.6 ± 0.3% day?1) in vitro, and the CY extracted using NaOH (62.3 ± 0.15%) was better than using KOH (32.0 ± 0.3%). In eutrophic medium, the DGR of H. musciformis (9.4 ± 2.1% day?1) was higher than that of K. alvarezii (5.0 ± 1.2% day?1). However, in this condition, the CY was similar for both species (50.2 ± 3.5%), and both species were effective in removing nutrients (30% NH4+, 18% NO2? and 2.4% ). H. musciformis did not survive when cultivated in the sea, neither in monospecific nor in multispecific cultivation. Moreover, K. alvarezii grew better in monospecific cultivation throughout the year (from 1.73 to 5.15% day?1) except during the wet period and the CY was high in both cultivation types (33.7–50.8%). We conclude that the cultivation of H. musciformis is not an alternative to K. alvarezii on the Brazilian southeastern coast. However, the results in vitro suggested its use as a complementary source of carrageenan or as a biological filter.  相似文献   

19.
The movements, behavior, and habitat utilization of yellowfin tuna, Thunnus albacares, following capture and release with archival tags in the Revillagigedo Islands Archipelago Biosphere Reserve (RIABR), Mexico, are described from analyses of 16 578 days of time‐series data, downloaded from 52 archival tags recovered from yellowfin (78–173 cm in length and 1.7–8.0 yr of age) at liberty from 93 to 1773 days ( = 411 days), collected during 2006–2012. An unscented Kalman filter model with sea‐surface temperature measurements integrated (UKFsst) was used to process the archival tag data sets to obtain improved estimates of geographic positions, most probable tracks (MPTs), and movement parameters. The MPTs indicate restricted movements, low levels of dispersion, and fidelity of yellowfin tuna to the RIABR. The median parameter estimates from the UKFsst model for errors in longitude (σx) and latitude (σy) were 0.46° and 1.84°, respectively, for directed movements (u and v) –0.05 NM day?1 and –0.05 NM day?1, respectively, and for dispersive movement (D) 117.99 NM2 day?1. Analyses of daily timed depth and temperature records resulted in the classification of the data into four distinct behaviors. There are significant differences among ages in the durations of Type I and Type II diving behaviors and in the daytime and nighttime vertical habitat utilization distributions. The oceanography surrounding the RIABR appears to have a profound influence on the movements, behavior, and habitat utilization of yellowfin in this area.  相似文献   

20.
Culture media formulation for Arthrospira maxima (formerly designated as Spirulina maxima) production is a constraining factor. Use of synthetic media could be expensive because most of the commercial strains require salinity conditions higher than 20 g/L. In this study, a traditional, pre‐Hispanic mineral resource, known as “tequesquite,” was used as the base for the formulation of an alternative and low‐cost culture medium. Tequesquite is available from outcrop areas located in the basin of the former Lake Texcoco, where A. maxima thrived in pre‐Hispanic times. The effect on the biomass production of different tequesquite‐based formulations, varying N, P, and , was tested and compared with results obtained with Zarrouk's medium (ZM). Growth of biomass in some alternative formulations showed no significant differences compared with ZM. Production in a bubble‐column photobioreactor of the alternative medium reached a maximum of X = 2570.4 mg/L dry weight, compared with X = 2931.4 mg/L dry weight obtained with ZM. The proposed tequesquite‐medium formulation has equivalent N and P concentrations as ZM, but only 50% of NaHCO3, thus reducing the medium's cost. In addition, it avoids the use of seawater or NaCl to provide the salinity condition required for the adequate growth of Arthrospira.  相似文献   

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