Limnology of Kharland (saline) ponds of Ratnagiri, Maharashtra in relation to prawn culture potential

The coastal saline soils, Kharlands, have great potential for their use in aquaculture. This study has been taken up to understand the limnology of the ponds in Kharland area for assessing their prawn culture potential. This study was carried out during September, 1999 to August, 2001. Each Kharland pond has an area of 0.045 hectare. During the study, depth of pond water was 47.7 to 120.0 cm, temperature varied from 25.7 to 34.5 degrees C; transparency from nil to 65.0 cm; specific conductivity from 1.78 to 94.5 microS.cm(-1); total dissolved solids from 0.89 to 27.55 ppt; pH 5.42 to 8.25; dissolved oxygen 1.6 to 8 mg.l(-1); free carbon dioxide 10.00 to 44.00 mg.l(-1); total alkalinity 5.00 to 142.00 mg.l(-1); salinity 0.45 to 39.55 ppt; total hardness 245.00 to 5945.00; calcium 56.05 to 1827.6; magnesium 110.74 to 4507.75 mg.l(-1); dissolved organic matter 1.45 to 9.68 mg.l(-1); ammonia 1.00-8.00 microg.l(-1); nitrite nil to 20.00 micro l(-1) and nitrate 7.5 to 17.5 microg.l(-1). These Kharland ponds are unique in physio-chemical characteristics during their seasonal cycle. From July to October, these ponds have nearly freshwater while from November to May pond water becomes saline. Thus, there is a great possibility of taking up monoculture of both the freshwater and brackish water prawns as well as polyculture of prawns and fishes in the Kharland ponds.     

Effect of calcium and magnesium on copper,cadmium, and some essential elements of Indian major carps Labeo rohita (Hamilton) and Catla catla (Hamilton) treated with copper and cadmium

The effect of calcium and magnesium either singly or in combination on accumulation of cadmium and copper in Labeo rohita (rohu) and Catla catla (catla) was investigated in this study under laboratory conditions. The investigation showed that copper accumulation in rohu exposed to 0.25 mg L^?1 of copper for 14 days reduced from 31.0 ± 0.4 mg kg^?1 at no calcium/magnesium treatment to 3.5 ± 0.2 and 2.2 ± 0.1 mg kg^?1, respectively, at 75 mg L^?1 calcium or magnesium treatment. The copper level in catla exposed to 0.20 mg L^?1 of copper for 14 days reduced from 5.7 ± 0.1 mg kg^?1 at no calcium/magnesium treatment to 3.4 ± 0.2 and 3.3 ± 0.1 mg kg^?1, respectively, at 300 mg L^?1 calcium or magnesium treatment. The cadmium accumulation in rohu exposed to 0.20 mg L^?1 of cadmium for 14 days reduced from 1.7 ± 0.1 mg kg^?1 at no magnesium treatment to 1.4 ± 0.1 mg kg^?1 at 120 mg L^?1 magnesium treatment. The cadmium accumulation in catla exposed to 0.20 mg L^?1 of cadmium for 14 days reduced from 0.8 ± 0.2 mg kg^?1 at no magnesium treatment to 0.6 ± 0.2 mg kg^?1 at 80 mg L^?1 magnesium treatment. Copper and cadmium treatments also reduced some essential microelements of rohu and catla. Both the fishes restored these elements at different levels of calcium and magnesium.     

Variations in physico-chemical and microbiological characteristics of water during breeding of Cyprinus carpio in a closed hatchery system

Physico-chemical and microbial characteristics of culture water were examined during the induced breeding of Cyprinus carpio in a controlled environmental system. Water temperature, dissolved oxygen, nitrate, phosphate, pH, ammonia nitrogen, total bacterial count, hardness, salinity, carbonate and bicarbonate were estimated before and after spawning and hatching. Average alteration in water pH before and after spawning was 7.91-7.57 and 7.86-7.58 respectively. Total hardness, carbonate and bicarbonate showed insignificant variations. Nitrate, ammonia nitrogen and phosphate contents significantly increased after spawning and hatching p < 0.05. The average increase in nitrate was from 2.94 to 8.62 microg l(-1) after spawning and 3.10 to 8.49 microgl(-1) after hatching. Ammonia nitrogen contents were sharply increased from an average of 0.011 to 1.87 mg l(-1) after spawning and 0.013 to 0.56 mg l(-1) after hatching. The average phosphates increased from 2.59 to 4.15 microg l(-1) after spawning and 2.61 to 4.03 microg l(-1) after hatching. Dissolved oxygen was sharply depleted even after a continuous aeration. Temperature played a vital role during breeding. No successful breeding was observed at a temperature of 17 degrees C or below and 31 degrees C or above. There is a significant association between temperature, spawning and hatching (p < 0.05). By optimizing temperature, the breeding success of this carp was achieved with a statistical significance of p < 0.05. Total bacterial count was significantly increased after spawning and hatching. It was related to the amount of discharge and may cause mass mortality of fish embryo and spawn in a closed hatchery system.     

Influence of some abiotic environmental factors on acute toxicity of inorganic lead to Cyprinus carpio var communis (Linn.) and Catla catla (Ham.) in simulated toxic aquatic environment

With the increase of water hardness from 60 to 720?mg/L CaCO₃, total alkalinity from 32 to 376?mg/L CaCO_3, pH from 7.6 to 7.9 and chloride from 28 to 350?mg/L, 96?h LC₅₀ on the basis of total lead increased from 8.2 to 1291?mg/L for Cyprinus carpio and 5.3 to 865?mg/L for Catla catla, when soil sediments were included these values were further raised to 1356 and 874?mg/L, respectively. The dissolved lead LC₅₀ values in all the treatments of soil and water was consistent with fixed amount of dissolved lead (1.04–1.78?mg/L) being needed for median lethal toxicity. Total lead toxicity also decreased with increase in pH from 6.3 to 11.3. 96?h LC₅₀ values increased for common carp 15 to 631?mg/L and for catla, 8 to 355?mg/L. But dissolved lead toxicity was found to increase with the increase of pH from 6.3 to 11.3 for both common carp (LC₅₀, 3.53 to 0.24?mg/L) and catla (LC₅₀, 2.21 to 0.09?mg/L). Removal of dissolved Pb with increasing carbonate content, particulate matter and pH due to adsorption, precipitation or coprecipitation reaction, reduced the dissolved lead concentration and thus the total lead toxicity. Increase in toxicity of lead with increase of exposure time was the biological response of longer contact time and decrease in dissolved lead toxicity with decrease in pH was due to increase H⁺ ion competition.     

The toxicity of ammonia,nitrite and nitrate to the fish,Catla catla (Hamilton)

The acute toxicity of unionized ammonia; nitrite and nitrate to the Indian major carp Catla catla (Hamilton) was determined using static and continuous flow through systems for 24 hours. The median lethal concentration (LC50) values for 24 h of ammonia (NH3-N), nitrite (NO2-N) and nitrate (NO3-N) were 0.045 mg/l, 120.84 mg/l and 1565.43 mg/l in static test respectively and were 0.036 mg/l, 117.43 mg/l and 1484.08 mg/l in continuous flow through test respectively.     

Toxicity and residue studies of fenvalerate to some selected freshwater fishes

The toxicity test of fenvalerate were conducted to fresh water fishes Labeo rohita (Hamilton), Catla catla (Hamilton), Cirrhinus mrigala (Hamilton), Aplocheilus punchex (Hamilton) and Ctenopharygodon idellus (Valenciennes). The static and continuous flow through tests were employed to determine the lethal concentration (LC50) for 24h, 48h and 96h to the test fish. It was observed that Cirrhinus mrigala is more sensitive to this pesticide followed by Applochielus punchex, Lebeo rohita, Catla catla and Ctenopharyngodon idellus. The residue analysis for qualitative confirmation was done by thin layer chromatography (TLC) to assess the deposition of pesticide in different tissues of fishes. The quantitative study of accumulation in the whole body tissue was done by Gas liquid chromatography (GLC). The quantitative residues confirm the toxic action.     

The Influence of Temperature and Salinity Upon the Acute Toxicity of Heavy Metals to the Banana Prawn (Penaeus merguiensis de Man)

Bioassays were conducted to determine the effects of temperature and salinity on the acute toxicity of mercury, copper, cadmium, zinc, nickel and lead to juvenile banana prawns (Penaeus merguiensis de Man). Tests were conducted at all combinations of 35, 30 and 20°C with 36 and 20° salinity over 96 h. The general rank order of metal toxicity was Hg > (Cu, Cd, Zn) > Ni > Pb. The toxicity of all metals increased with increased temperature. This was most noticeable in the high salinity treatments, particularly for copper and zinc. Salinity appeared to influence the toxicity of all metals tested although significant differences were only found for copper and lead at 20°C. At this temperature prawns were markedly more susceptible to both metals in low salinity sea water. The data are compared with lethal concentrations found for other crustaceans and are discussed in relation to existing water quality criteria.     

Effect of phenol on haematological components of Indian major carps Catla catla, Labeo rohita and Cirrhinus mrigala

The effect of phenol on haematological components of Indian major carps, Catla catla, Labeo rohita and Cirrhinus mrigala were observed. After exposure to sublethal concentrations of 5.17 mg l(-1), 6.06 mg l(-1) and 6.99 mg l(-1), the number of red blood cells, haemoglobin content and packed cell volume all decreased but the glucose level increased. The order of decrease in the haematological components of the three fish is in the order of Catla catla > Labeo rohita > Cirrhinus mrigala.     

不同硬度条件下Cd~(2+)和Cu~(2+)对稀有鮈鲫的急性毒性

为研究水体硬度对稀有鮈鲫Cd~(2+)和Cu~(2+)毒性效应的影响,开展了96 h急性毒性试验。试验结果发现,当水体硬度(以CaCO_3计,下同)为50 mg·L~(-1)、250 mg·L~(-1)、450 mg·L~(-1)时,Cd~(2+)对稀有鮈鲫的96 h半数致死浓度(96 h-LC50)分别为4.30 mg·L-1、12.06 mg·L~(-1)、19.99 mg·L~(-1),对应的安全浓度(SC)依次为0.430 mg·L~(-1)、1.206 mg·L~(-1)、1.999 mg·L~(-1);Cu~(2+)对稀有鮈鲫的96h-LC50分别为0.046 mg·L-1、0.148 mg·L~(-1)、0.228 mg·L~(-1),对应的SC依次为0.0046 mg·L~(-1)、0.0148 mg·L~(-1)、0.0228 mg·L~(-1)。计算得到Cd~(2+)对稀有鮈鲫急性毒性与水体硬度的拟合方程为ln 96 h-LC50=0.687 ln H~(-1).243(r=0.998);Cu~(2+)对稀有鮈鲫急性毒性与水体硬度的拟合方程为ln 96 h-LC50=0.727 ln H-5.923(r=0.999),Cd~(2+)和Cu~(2+)对稀有鮈鲫的硬度斜率分别为0.687和0.727。这些结果表明,水体硬度可有效降低Cd~(2+)和Cu~(2+)对稀有鮈鲫的急性毒性,且稀有鮈鲫的硬度斜率与其他物种差异较大。在评估不同硬度水体下Cd~(2+)和Cu~(2+)的生物毒性及其生态风险时,应根据测试物种特异的硬度斜率而定。     

Seasonal variations in physico-chemical parameters and heavy metals in water and sediments of Uppanar estuary, Nagapattinam, India

The present study was carried out to determine the physico-chemical characteristics and heavy metals in water and sediments in Uppanar Estuary, Nagapattinam, Southeast coast of India during January to December 2007. The minimum and maximum values of atmospheric and surface water temperatures (degrees C), salinity (per thousand), pH and dissolved oxygen (ml l(-1)) were: 26.0-35.0; 25.0-33.5; 8.0-35.0; 7.2-8.2 and 2.8-5.5 respectively. The ranges of nitrate, nitrite, phosphate and silicate were: 7.05-24.23; 0.82-3.15; 0.31-2.18 and 40.0-198.0 (microM) respectively. The ranges of heavy metals in water (microg 1(-1)) and sediment (microg g(-1)) copper zinc, cadmium and mercury were: 2.45-18.25; 26.43-101.24; 1.23-24.35 and 0.01-0.22 and 5.02-81.27; 22.47-75.42; 2.25-10.06 and 0.01-0.16 respectively.     

Seasonal variations in zooplankton abundances in the Iturbide reservoir (Isidro Fabela, State of Mexico, Mexico)

This studywas undertaken to quantify the seasonal variations of zooplankton (rotifers, cladocerans and copepods) and selected physico-chemical variables (temperature, pH, conductivity, Secchi disc transparency, dissolved oxygen, ammonia, nitrate and phosphate concentrations) in the Iturbide dam. Monthly zooplankton samples (50 l filtered through 50 microm mesh, in duplicates from each of the 4 stations) were collected from February 2008 to January 2009. Simultaneously physico-chemical variables were measured. The zooplankton samples were fixed in 4% formalin in the field. In general, the temperature ranged from 9 to 16 degrees C, rarely exceeding 20 degrees C. Secchi transparency was nearly 100% since the reservoir was shallow (< 2 m) even during the rainy seasons. Dissolved oxygen was generally high, 13-18 mg l(-1). Nitrate levels (10 to 170 microg l(-1)) were low while phosphates were relatively high (9 to 35 microg l(-1)). The Iturbide reservoir was dominated by rotifer species. We encountered in all, 55 taxa of rotifers, 9 cladocerans and 2 copepods. The rotifer families Trichocercidae and Notommatidae had the highest number of species (7 each) followed by Colurellidae and Lecanidae (6 and 5 species, respectively). Trichocerca elongata, Ascomorpha ovalis, K. americana, K. cochlearis, Lepadella patella and Pompholyx sulcata were the dominant rotifers during the study period. On an annual average, rotifer density ranged between 50-200 ind.(-1). Among crustaceans Chydorus brevilabris and Macrothrix triserialis were most abundant. The maximal density of these cladocerans was about 50 ind. l(-1). Copepods were much lower in numbers (< 20 ind. l(-1)). In general the density of zooplankton was higher during summer months (April to July) than during winter. Shannon-Wiener diversity index varied from 1.0 to 4.3 depending on the site and the sampling period. Based on the data of Secchi transparency and nutrient concentrations, the Iturbide reservoir appeared to be mesotrophic.     

Effect of temperature on growth and reproduction of the epigeic earthworm,Eudrilus Eugeniae (Kinberg)

Influence of temperature on growth and reproduction of Eudrilus eugeniae has been investigated by laboratory culturing at regulated 25.0 degrees C, 30.0 degrees C, 37.5 degrees C and 40.0 degrees C and in fluctuating (22.7-27.3 degrees C) room temperature of prevailing (winter) season over 16 weeks. All worms died during first and tenth week at 40.0 degrees C and 37.5 degrees C respectively. Weight (biomass) and growth of worms cultured at different temperature varied significantly (P<0.01). The mean growth (mg/g live weight/day) at 25.0 degrees C., 30.0 degrees C, 35.0 degrees C, 37.5 degrees C and in fluctuating temperatures was 1,074.04 +/- 6.07, 1,554.01 degrees 192.37, 148.1 +/- 15.28, 192.83 +/- 25.8 and 1450.4 +/- 162.1 respectively. Growth declined after maturity drastically with coccon production. At 25.0 degrees C though worms are sexually mature, they failed to produce cocoons within 16 weeks whereas, at 35.0 degrees C and 37.5 degrees C they did not sexually mature. Worms attained sexual maturity at a mean weight of about 1000 mg/worm. The mean per cent maturity was higher and earlier in fluctuating temperatures and at 30.0 degrees C than at 25.0 degrees C. Cocoon production was observed only at 30.0 degrees C and in fluctuating temperatures with a mean of 0.9 and 1.5 cocoons/ wom/week and the cumulative cocoon number of 10.8 and 14.7/worm over 16th week respectively. The fluctuating temperature of uncontrolled room environment and 30.0 degrees C were favorable for various life activities of the worms. Eudrilus eugeniae appears to have range of temperature optima more than 25.0 degrees C and less than 28 degrees C. The climatic conditions prevailing in whole of the peninsular India during winter season are favourable for employing this worm in intensive field scale vermiculturing practices.     

Pollution status and conservation strategies of Moirang River, Manipur with a note on its aquatic bio-resources

An attempt has been made to evaluate pollution status and aquatic bio-resources of the Moirang river near its mouth in the Loktak Lake. The river water is considered polluted as it has high concentration of free CO2 (14.8 mg/l), nitrite-nitrogen (0.040 mg/l), inorganic phosphorus (0.107 mg/l and faecal coliform bacteria (162/100 ml). Aquatic bio-resources of the river include 24 species of fishes representing 20 genera of 13 families and 16 species of macrophytes representing 14 genera of 9 families. The floral and faunal compositions of the river were mostly widely distributed forms that can survive in polluted environments. Fishery potential and conservation strategies of the river are discussed.     

Water quality assessment of Fort lake of Belgaum (Karnataka) with special reference to zooplankton

Study on limnobiotic status of the Fort lake water was made to assess the potability of water from Feb 1998 to Jan 1999. Fort lake exhibits high alkalinity with pH ranging from 8.36 (June) to 10.6 (Feb and March), total alkalinity (TA) from 88 to 188 mg/l, total hardness (TH) from 59.8-217 mg/l, PO4 (7.2 to 13.6 mg/l and BOD (42.6-60.6 mg/l). From the observations it can be known that the Fort lake water is inferior and not suitable for drinking purposes. The possible factors for its poor quality have been discussed.     

Effects of industrial waste water on heavy metal accumulation, growth and biochemical responses of lettuce (Lactuca sativa L.)

The waste water showed high values of total solid (TS), hardness and chloride with slightly alkaline pH along with high concentrations of Cr (2.03 mg l(-1)), Ni (1.59 mg l(-1)) and Zn (0.46 mg l(-1)). The concentration of Cu (0.21 mg l(-1)) and Zn in industrial waste water was low than Ni and Cr. The diluted (25 and 50%), undiluted (100%) waste water was used to irrigate the lettuce plants grown in alluvial soils. Plants accumulated heavy metals in their shoot (Ni, 13.65; Cr, 19.73; Zn, 21.6 and Cu 14.76 microg g(-1) dry weight) and root (Ni, 41.4; Cr, 31.6; Zn, 30.2 and Cu 15.85 microg g(-1) dry weight) in high concentrations after irrigation with undiluted industrial waste water. Maximum accumulation of heavy metals was found in the root than the shoot (13.65-21.60 microg g(-1) dry weight). Dry matter yield and biomolecules (Chlorophyll a, b and sugar contents) was found to increase with increase in concentration of waste water up to 50%, which declined at the exposure of undiluted waste water. Catalase activity was found to increase with increase in waste water concentrations up to 100%, while carotenoids content increased in plants only up to the 50% waste water irrigation. Use of industrial waste water in such form, on agricultural lands is not found suitable without proper treatment. It could be injurious to plants growth and may be a potential threat to food web.     

Veränderung der Zinktoxizität in Wässern geringer und hoher Wasserhärte unter dem Einfluß eines synthetischen Huminstoffes

In soft water 5mg/l of a synthetic dissolved humic substance (HS) reduced the toxicity of zinc against zebrafish embryo and larvae. The appliation of this HS as an antidot against fish hazardous zinc concentrations particulary in soft water is possible. In hard water the HS is able to change the detoxification effect of high water hardness because of the interaction between the calcium and magnesium ions and the HS. In this case the protective effect of high water hardness against trace metals is reduced because of the adhesion of hardness producing ions (Ca²⁺, Mg²⁺) with the HS.     

Temperature effects on the toxicity of four trace metals to adult spotted Babylonia snails (Babylonia areolata)

A study was conducted to determine the median lethal toxicity of four heavy metals on the marine gastropod Babylonia areolata. Median lethal toxicity tests were conducted to observe the sensitivity of this gastropod to metals and how variations in temperature might affect toxicity of test elements. Four heavy metals were used in the study. It was observed that the 96-hr LC₅₀ (in mg/L) for the different metals was found to be nickel (Ni) 33.53 (35.22–28.43), copper (Cu) 44.59 (46.43–41.53), cadmium (Cd) 21.53 (23.43–18.37), and zinc (Zn) 27.34 (28.81–24.24) at room temperature 24 °C. With temperature as a variable, median lethal concentration (LC₅₀) values were observed to increase from 22.41 mg/L at 10 °C to 27.34 mg/L at 28 °C and reduce to 18.43 mg/L at 30 °C and a further rise in toxicity was observed at 35 °C where LC₅₀ value was 12.7 mg/L as seen in the case of Zn. It was also observed that at 40 °C thermal and chemical toxicity overlapped as 100% mortality was observed in controls. This trend was noted in all metals for Babylonia areolata indicating that temperature played an important role in determining LC₅₀ values of toxicants.     

Population dynamics of the tropical cladoceran Ceriodaphnia rigaudi Richard, 1894 (Crustacea: Anomopoda). Effect of food type and temperature

The knowledge of population effects of food on tropical, filter-feeding cladocerans is scarce because a reduced number of species has been extensively studied. Ceriodaphnia rigaudi Richard 1894, a small-sized cladoceran distributed mainly in tropical and subtropical regions of the world, was studied. The aim of this study was to contribute to the knowledge of the reproductive biology of a poor-known Cladoceran; for this we assessed the effect of feeding and temperature on the reproduction and life cycle of this species. Three microalga species (Pseudokirchneriella subcapitata, Ankistrodesmus falcatus, and Chlorella vulgaris) were supplied as food each at a concentration of 12 mg l(-1) (dry weight, equivalent to 1.3 x 10(6), 0.4 x 10(6) and 1.35 x 10(6) cell m1(-1), respectively, and equivalent to 7.8 microg C ml(-1), at two temperatures (20 and 25 degrees C). We evaluated, among other responses, longevity, total progeny, survival, life expectancy at birth and fecundity. Organisms fed with the microalgae A. falcatus and P subcapitata presented both higher longevity (30.7 +/- 5.91, 26.6 +/- 3.59 days, respectively) and total progeny (45 +/- 13.80, 40.7 +/- 0.66 neonates female (-1) values than those organisms fed C. vulgaris (13.5 +/- 4.63 days and 17.6 +/- 6.19 neonates female (-1), respectively). On the other hand, temperature affected significantly the population parameters of C. rigaudi, recording maximal longevity values (56.1 +/- 9.41 days) at 20 degrees C in organisms fed A. falcatus; however, age at first reproduction and total progeny were negatively affected by this temperature: sexual maturation of the females was delayed until the age of 16 days and the number of neonates produced was smaller (9.8 +/- 3.45 with C. vulgaris; 24.7 +/- 6.01 with P subcapitata, and 35.5 +/- 8.59 neonates female(-1) with A. falcatus). The best reproductive responses for C. rigaudi in this study were obtained with A. falcatus at degrees 25 degrees C.     

Comparative studies on the metabolism of shallow-water and deep-sea marine fishes. II. Red-muscle metabolism in shallow-water fishes

Maximal rates of oxygen consumption in vitro have been measured under standardized conditions at three test temperatures (5°, 15°, 25°C) on minced preparations of red muscle from 10 species of shallow-water marine teleost fishes. These fishes came from three different geographic areas, two with cool average water temperatures (near 15°C: coastal southern California, Galápagos Islands) and one with warm average water temperatures (near 25°C: Hawaiian Islands). The group is made up of post-juvenile or adult epipelagic fishes, which are moderately or very active in terms of their locomotor activities. A large part of the range of phylogenetic diversity among the teleosts is represented, as is the body weight range from a few grams to several kilograms. The purpose of the work is to provide part of a set of tissue-metabolism data on shallow-water fishes for future comparison with similar results from deep-sea species. Of 8 complete curves for oxygen uptake rate versus temperature (R-T curves), 6 are normal in shape (Q₁₀1.5), 1 is normal but with a low Q₁₀, and 1 is partly flat, partly normal. The differences between the species in terms of both absolute positions and slopes of the R-T curves are not related in any consistent way to any of the three testable variables: phylogenetic position, long-term adaptation temperature, and body size. The red muscles of a variety of adult epipelagic fishes, at ecologically realistic temperatures, are shown to be exceptions to the general rule that tissues of ectothermous lower vertebrates have lower metabolic rates than comparable tissues of non-torpid endothermous higher vertebrates. This circumstance probably is a major factor in the great capacities for sustained high-speed swimming shown by most epipelagic fishes. Other physiological and ecological implications of the results are discussed.