Seasonal changes in the abundance and biomass of zooplankton from shallow mudflat river-estuarine system in Persian Gulf

The present study was designed to investigate the seasonal changes in the abundance and biomass of zooplankton and their relationships with water quality parameters in mudflat shallow estuary, Helleh River, Persian Gulf (Iran). The zooplankton consisted of Acartia sp., Euterpina sp., Oithona spp., Oncaea sp., Paracalanus sp., Corycaeus sp., Labidocera sp., Macrosetella sp., Microsetella sp., Temora sp., copepod copepodid, copepod nauplii, Barnacle, Polychaeta, Conchoecia sp. (Ostracoda), Hyperid, Decapoda (zoea and megalopa), Actinula, Echinopluteus, Mollusca, Tintinnopsis sp., Ctenophora (Boliopsis sp.), Protozoa (Discorbis sp.), cumacea (Diastylis sp.), Cnidaria (Siphonophora and Phialidium), Nematoda (Pratylenchus spp.), Urocordata (Oikopleura spp.), fish eggs and fish larvae. The maximum biomass was estimated at estuary mouth in all seasons, the highest values in autumn (97.8-255.6 mg/m3) and the lowest in winter (5.5-68.2 mg/m3). The seasonal abundance (density) of zooplankton was 21237±2419, 45739±6053, 5242±648, and 12905±1867 ind./m3 in summer, autumn, winter and spring, respectively. There was a significant correlation (P<0.01) between zooplankton abundance as well as biomass with salinity, dissolved oxygen and chlorophyll a. Based on PCA (Principal Component Analysis), the most important factors in mudflat shallow river–estuarine system that could describe most changes of biomass and abundance of zooplankton were salinity, chlorophyll a, temperature and pH,  respectively.The present study was designed to investigate the seasonal changes in the abundance and biomass of zooplankton and their relationships with water quality parameters in mudflat shallow estuary, Helleh River, Persian Gulf (Iran). The zooplankton consisted of Acartia sp., Euterpina sp., Oithona spp., Oncaea sp., Paracalanus sp., Corycaeus sp., Labidocera sp., Macrosetella sp., Microsetella sp., Temora sp., copepod copepodid, copepod nauplii, Barnacle, Polychaeta, Conchoecia sp. (Ostracoda), Hyperid, Decapoda (zoea and megalopa), Actinula, Echinopluteus, Mollusca, Tintinnopsis sp., Ctenophora (Boliopsis sp.), Protozoa (Discorbis sp.), cumacea (Diastylis sp.), Cnidaria (Siphonophora and Phialidium), Nematoda (Pratylenchus spp.), Urocordata (Oikopleura spp.), fish eggs and fish larvae. The maximum biomass was estimated at estuary mouth in all seasons, the highest values in autumn (97.8-255.6 mg/m3) and the lowest in winter (5.5-68.2 mg/m3). The seasonal abundance (density) of zooplankton was 21237±2419, 45739±6053, 5242±648, and 12905±1867 ind./m3 in summer, autumn, winter and spring, respectively. There was a significant correlation (P<0.01) between zooplankton abundance as well as biomass with salinity, dissolved oxygen and chlorophyll a. Based on PCA (Principal Component Analysis), the most important factors in mudflat shallow river–estuarine system that could describe most changes of biomass and abundance of zooplankton were salinity, chlorophyll a, temperature and pH,  respectively

Population Growth and Production of Apocyclops dengizicus (Copepoda: Cyclopoida) Fed on Different Diets

This study was carried out to investigate the effects of various diets: 4 monoalgal diets: Nannochloropsis oculata (N), Isochrysis galbana (I), Chaetoceros calcitrans (C), and Tetraselmis tetrathele (T); 4 mixed algal diets: N+I+C+T(NICT), N+I+C(NIC), C+T(CT), and I+T(IT); and 2 nonalgal diets: baker’s yeast (BY) and prepared shrimp feed (SF) on population growth and density of Apocyclops dengizicus. The type and density of diet had significant effects on the growth and density of A. dengizicus (P , 0.01). Of tested diets, T and CT were optimum diets due to higher density and growth rate of A. dengizicus compared to other diets. Their high dietary value was related to the higher contents of polyunsaturated fatty acid, particularly docosahexaenoic acid (22:6n-3), eicosapentaenoic acid (20:5n-3), and arachidonic acid (20:4n-6) compared to A. dengizicus cultured on other diets. The results of the present study illustrated that T. tetrathele was the most suitable food for the culture of A. dengizicus

Ingestion rate of postlarvae Penaeus monodon fed Apocyclops dengizicus and Artemia

Three different live diets including; Apocyclops copepodids, Artemia nauplii, and combination of Apocyclops copepodids and Artemia nauplii were offered to two groups of Penaeus monodon larvae viz PL3–6 and PL9–12. The prey diets were offered to each group at three density levels (6, 13 and 20 μg dry weight/ml). The results showed that PL3–6 P. monodon larvae consumed Apocyclops copepodids (CII–CIV) at 5.1–14.3 ind./day, the Artemia nauplii at 18.4–39.2 ind./day, and mixture of Apocyclops and Artemia at 12.2–41.5 ind./day. Similarly, PL9–12 P. monodon larvae ingested Apocyclops at 12.6–51.7 ind./day, Artemia at 62.4–101.6 ind./day, and their mixture at 48.0–65.3 ind./day. This study indicated that P. monodon larvae, at PL3–6 and PL9–12, can ingest Apocyclops selectively better than Artemia at 1:1 ratio as shown by the improved body dry weight of the larvae

Use of Cyclopoid Copepod Apocyclops dengizicus as Live Feed for Penaeus monodon Postlarvae

In this study, the suitability of cyclopoid copepod Apocyclops dengizicus as a live food for black tiger shrimp, Penaeus monodon, postlarvae was investigated. After 14 d, P. monodon postlarvae (PL1) had survival rates of 41.7 ± 2.9% (mean ± SE), 28.7 ± 1.2%, 56.3 ± 3.7%, 4.4 ± 1.9%, and 2.8 ± 1.0% when fed A. dengizicus (CC), Artemia nauplii (AN), mixture of A. dengizicus and Artemia nauplii (CC + AN), artificial shrimp feed (SF), and microalga Tetraselmis tetrathele (TT), respectively. Specific growth rates (SGRs) of P. monodon were maximum (14.2 ± 0.6%/d) in CC + AN, followed by CC (11.0 ± 0.4%/d), AN (9.3 ± 0.7%/d), SF (6.1 ± 0.2%/d), and TT (6.0 ± 0.5%/d). The total n-3 fatty acids of postlarvae increased from 20.6 to 25.8% when fed with CC, 28.8% with AN, and 29.0% with CC + AN. Better survival and SGRs of P. monodon postlarvae could be attributed to docosahexaenoic acid : eicosapentaenoic acid : arachidonic acid ratio of CC (10.2:3.2:1) diet. The results of this study showed that A. dengizicus has a potential to be used as a substitute live feed for P. monodon postlarvae because of better survival, growth, and high polyunsaturated fatty acids

Culture of a Planktonic Cyclopoid, Apocyclops Dengizicus (Lepeshkin, 1900) and Its Suitability as Live Feed for the Postlarvae of Giant Black Tiger Shrimp, Penaeus Monodon Fabricus (1798)

Copepods form an important link between phytoplankton and higher trophic levels such as fish and shrimp. In aquaculture industry, some species of copepods are used as live feed for fish and shrimp larvae. In this study the suitability of a copepod Apocyclops dengizicus as a live food was investigated. For establishment of successful culture protocol, the biology (feeding, reproduction, and growth) and environmental requirements (salinity, temperature, light intensity, and photoperiod) of A. dengizicus were studied Apocyclops dengizicus can reproduce in salinity levels from 5 through 35 ppt. The salinity level of 20 ppt gave maximum production (535.3 ± 30 ind./female). At temperature levels between 20 ºC to 35 ºC, the mean maximum production (386.3 ± 60.3 ind./female) was obtained at 35 ºC. Culture of A. dengizicus at different light intensity levels (from 33.3 to 162.1µmol/m2/s), showed that the mean maximum production (523 ± 37.4 ind./female) was observed at 33.3 µmol/s/m2. In different photoperiods, the mean maximum production (647.5 ± 144 ind./female) was attained at continuous light exposure. Feeding rates of A. dengizicus varied from nauplius to adult (p<0.01). The best feed for all stages of A. dengizicus were Tetraselmis tetrathele, Chaetoceros calcitrans, Isochrysis galbana and Nannochloropsis oculata respectively. The algal species and their densities showed significant effects on the growth rates of A. dengizicus population (p<0.01). Of different algal diets tested, copepod fed with Tetraselmis tetrathele and its combination with other microalgae gave fastest development, maximum offspring production, and maximum production. Nutritional analysis of A. dengizicus revealed that it has 23-60 % protein, 18-20 % lipid, and 4-10 % carbohydrate. Phenylalanine and leucine had the highest concentrations ranging from 12.4 to 26.3 % and 11.3 – 12.2 % respectively. Saturated fatty acids (SFA) constituted the major part of the fatty acids (40.54 ± 5.97 %) followed by mono unsaturated fatty acids (MUFA) (20.67 ± 7.21 %) and highly unsaturated fatty acids (HUFA) (20.69 ± 4.90 %). The major SFA, MUFA, and HUFA for A. dengizicus were C14:0 (30.47 ± 4.61%), C18:1n-7 plus C18:1n-9 (14.23 ± 4.96%) and C22 : 6n-3 (10.54 ± 3.14%) respectively. Considerable increase in n-3/n-6 and DHA/EPA ratios for A. dengizicus compared to newly hatched Artemia nauplii make it as suitable nutritious prey for fish and shrimp larvae. This study showed that the best ingestion rates for Penaeus monodon larvae were 41.5 ind./day for PL3-6 fed on Apocyclops and 101.6 ind./day for PL9-12 for Artemia. The shrimp larvae could also ingest selectively Apocyclops better than Artemia. Experiments on the survival and growth rates of P. monodon larvae fed with different diets showed that survival and growth rates of P. monodon were maximum (56.3%, 14.24 %/day) in mixed diet of A. dengizicus + Artemia nauplii. The n-3/n-6 ratios of larvae increased from 1.88 to 2.56 when fed with Apocyclops, 2.46 with Artemia, and 2.40 with Apocyclops and Artemia. This study illustrated that A. dengizicus has high potential as live feed for P. monodon and could partially replace the imported Artemia cyst

Effects of different types of herbicides and insecticides on population of green microalgae Scenedesmus quadricauda

Introduction:Agricultural pesticides into aquatic ecosystems of use discriminate eventually devastating impact on the populations of aquatic species.Sensitivity of  algae to various pollutants such as herbicides, organochlorin, heavy metals and industrial organic matter has been shown in various studies. In addition to its application, checking the pollution is common. This study aimed to investigate the effects of different concentrations of two groups of herbicides, (macheteand saturn), and insecticides (malathion and diazinon) on the population of green algae (Scenedesmusquadricauda) with 96 hour EC50. Materials and methods: The experiment was conducted in a completely randomized design during 96 hours in 4 treatments (four levels of pesticide and control) and 3 replicates in accordance with the standard method, OECD. The exposure regime consisted of a 12-hour photoperiod with a 12:12light-dark regimewith intensity of 80 µmol photons/m2/s in BBM medium (Bold Basal Medium) at 22± 2 °C. Results: Statistical analysis of results also showed significant differences in daily growth rate (p < 0.05) between some different concentrations of studied toxic material, as the significant changes in the cell density observed by increasing concentrations of toxins. The highest mortality rate caused by herbicides in 52.81 µg/L of saturn and 58.36 µg/L ofmachete, and by insecticides in 63.76 µg/L of malathion and 6.087 µg/L. Also, 96 hour EC50was determined, as 174.234 µg/L for diazinon, 9.858 µg/L formalathion,1.9µg/L formachete and 1.029µg/Lfor Saturn. Discussion and conclusion: According to the results of this study, (Scenedesmus quadricauda) can be used as a biological indicator in aquatic ecosystems while it needs more extensive and intensive studies

Effects of salinity, temperature, light intensity and light regimes on production, growth and reproductive parameters of Apocyclops dengizicus

The effects of salinity, temperature, and light conditions on production and development, longevity, survival and sex ratios of the cyclopoid copepod, A. dengizicus were determined. Seven different salinity levels (5, 10, 15, 20, 25, 30, 35 psu), four temperatures (20, 25, 30, 35 °C), three different light intensities (33.3, 85.3, 162.1 μmol photons/ m2/ s) and light regimes (24:0, 0:24, and 12:12 h light:dark regime) were employed . The highest production was achieved under 20 psu salinity. The optimum temperature required for the maximum reproduction and shortest development time was 35 °C. The production was highest (p<.05) and development rate of A. dengizicus was shortest (p<.05) under the lowest light intensity (33.3 μmol photons/ m2/ s). Continuous light (24:0 h LD) showed positive effects on growth and production. Light regimes 24:0 h and 12:12 h LD yielded the highest total production and growth (p<.05), with highest (p<.05) survival percentage. This study demonstrated that A. dengizicus can tolerate wide range of environmental conditions and can be cultured for commercial live feed purposes as well as toxicity studies

Nutritional values of Apocyclops dengizicus (Copepoda: Cyclopoida) fed Chaetocerous calcitrans and Tetraselmis tetrathele

The cyclopoid copepod Apocyclops dengizicus was isolated from a marine shrimp pond, Penaeus monodon, Kuala Selangor, Malaysia, and reared in the laboratory for 3 months to establish a pure population stock. Amino acids and fatty acids of A. dengizicus were determined when fed Chaetocerous calcitrans (C), Tetraselmis tetrathele (T) and their combination (CT) (1:1 by number). The protein contents in A. dengizicus that received C, T and CT were 46.8%, 60.5% and 55.3% of dry weight respectively. Correspondingly, the lipid was 19.0%, 17.8% and 19.1% of dry weight for C,T and CT respectively. TheA. dengizicus cultured on C, T and CT had total essential amino acids without tryptophan measurement of 57.1, 60.3 and 67.8 and total non-essential amino acids of 42.9%, 40.0% and 32.2% of total amino acids. The fatty acid content of A. dengizicus showed that it was able to synthesize docosahexenoic acid (22:6n-3, DHA), eicosapentaenoic acid (20:5n-3, EPA) and arachidonic acid (20: 4n-6, ARA) from examined microalgal diets. The DHA:EPA:ARA ratios of A. dengizicus fed on C, T and CT were 6.8:3.0:1, 14.0:5.8:1 and 11.6:2.6:1 respectively. Apocyclops dengizicus could be suitable live food for larval ¢sh and shrimp rearing because it meets their nutritive requirements

Culture experiments with a freshwater cladoceran, Ceriodaphnia quadrangula (O. F. Müller, 1785), as suitable live food for Mayan cichlid (Cichlasoma urophthalmus) larvae

Effects of five different diets of green microalgae, Scenedesmus quadricauda (S), poultry manure (P), cattle manure (C), and two mixed diet of P+C (PC) and S+P+C (SPC); and interaction effects of water temperature (20, 25, 30°C) and photoperiod (24:0, 0:24, and 12:12, hours light: hours dark) on production and growth of Ceriodaphnia quadrangula were examined separately. Then, mass cultivation of C. quadrangula and its application for rearing of an ornamental fish larva, Mayan cichlid (Cichlasoma urophthalmus) were carried out. Results showed that mean population density and specific growth rate (SGR) of C. quadrangula obtained 0.15-3.70 ind. mL-1 (150-3700 ind. mL-1) and 0.019-0.18 day-1, respectively, maximum with S diet and minimum with C diet. The better mean population density and SGR for C. quadrangula determined at interactions 25 ºC with 24:0 and 12: 12, L:D, respectively, which was significantly higher than that at interactions 20 ºC and 30 ºC. Nutritional analyses showed that protein and lipid contents of C. quadrangula were 54% and 12.3% dry weight, respectively. The fatty acid contents of C. quadrangula were 27.3% and 63.7% of saturated and unsaturated fatty acids, respectively. Among PUFAs (Polyunsaturated Fatty Acids) content, 18:2n-6 and 18:3n-3 were in highest level. Early cichlid larvae (5-weeks-old, 15.8 mm length and 110 mg weight) and advanced larvae (10-weeks-old, 25.6 mm length and 240 mg weight) consumed C. quadrangula at range 220–584 ind. day-1 larvae-1 and 528–1956 ind. day-1 larvae-1, respectively, as well as suitable growth and survival rate. This study demonstrated that C. quadrangula could be used as live feed purposes for larval rearing in aquaculture

Investigation of the Kinetics and Nature of Malachite Green Biosorption by Green Microalgae

In the present study, the Box-Behnken design was used to investigate the effects of the four main parameters of initial Malachite green )MG( concentration, initial solution pH, algae content, and contact time on the efficiency of dye biosorption by the green microalgae Scenedesmus quadricauda and Chlorella vulgaris. The results showed that maximum dye removal efficiencies of S. quadricauda and C. vulgaris biomasses for the biosorption of MG were 76.23 and 91.32%, respectively. Under optimum conditions, the pseudo-second order fitted with the experimental data much better than other similar models (R2>0.99). The FT-IR spectroscopy method showed that several functional groups, especially carboxyl, hydroxyl, and amine groups, present on the surface of the S. quadricauda and C. vulgaris biomasses are responsible for binding of MG ions in the biosorption process. The differences observed in the MG biosorption efficiencies of algal biomasses may be attributed to differences in interactions between the dye molecules and the algal biomasses. Finally, the findings revealed that the algal biomasses used in this study are suitable as the biomaterial for MG biosrption from wastewaters