Aquatic Vegetation, Largemouth Bass and Water Quality Responses to Low-Dose Fluridone Two Years Post Treatment

Whole-lake techniques are increasingly being used to selectively remove exotic plants, including Eurasian watermilfoil ( Myriophyllum spicatum L.). Fluridone (1-methyl-3-phenyl- 5-[3-(trifluoromethyl)phenyl]-4(1 H )-pyridinone), a systemic whole-lake herbicide, is selective for Eurasian watermilfoil within a narrow low concentration range. Because fluridone applications have the potential for large effects on plant assemblages and lake food webs, they should be evaluated at the whole-lake scale. We examined effects of low-dose (5 to 8 ppb) fluridone applications by comparing submersed plant assemblages, water quality and largemouth bass ( Micropterus salmoides ) growth rates and diets between three reference lakes and three treatment lakes one- and two-years post treatment. In the treatment lakes, fluridone reduced Eurasian watermilfoil cover without reducing native plant cover, although the duration of Eurasian watermilfoil reduction varied among treatment lakes. (PDF has 11 pages.)

The effect of the drug colchicine on the early life of fish

The alkaloid drug colchicine is a mitotic inhibitor. The results of this study show that colchicine influence the normal functioning of the mitotic process in Sarotherodon galilaeus, S. melanotheron and the hybrid S. galilaeus, X S. melanotheron leading to the production of unusual chromosomal events such as anaphase bridges, laggards and polyploid cells. These unusual events could have serious genetic implications in the area of variability of the chromosome number. The use of colchicine also produces results with consistent karyotypes and better morphology as well as providing detailed information on the behaviour of the chromosome of the early life of fish. The knowledge of such information will be of great use in cytotaxonomy, fish breeding and in studying the effects of sub-lethal levels of water pollutants on fish

Use of homeo drug for curing ulcerative syndrome in fishes

Fungal infection was observed in Catla catla and Labeo rohita cultured in two private fish farms. The later stage of the infection resulted in ulcerations followed by haemorrhage on the dorsal surface of the body. Initially, usual treatments of copper sulphate, potassium permanganate and common salt solution were tried, but no improvement was observed. Then repeated intramuscular injections of homeopathic drug Heaper Sulpher and Arnica spray were given with encouraging results. Infection reported in another farm was also successfully controlled using a similar treatment.

Pathogenicity of Aeromonas sobria to Thai silver barb (Barbodes gonionotus Bleeker) and its sensitivity to some antibiotic agents

Five isolates of Aeromonas sobria, collected from the diseased fish were selected for detection the pathogenicity following water-born infection method on silver barbs (Barbodes gonionotus) at the selected exposure dose 2.5x10⁸ CFU/ml which was standardized by preliminary test. In the experimental condition lesion and mortality were found in fishes. Among the isolate, Ass17 Ass19, Ass31 and Ass36 were successfully infected 20-60% fishes. Another isolate Ass20 was found non-pathogenic. Drug sensitivity test was performed by six antibiotics viz. Oxytetracycline, Oxolinic acid, Chloramphenicol, Stilphamethozazole, Streptomycin, Erythromycin. All the isolates showed variable reaction patterns to antibiotics. Most of the isolates were found sensitive to Oxytetracycline (OT), Oxolinic acid (OA) and Chloramphenicol (C) but resistance to Erythromycin and Sulphamethoxazole (SXT). Isolate Ass31 found resistant to Oxolinic acid.

Limit of drug residues in aquatic products (NY5071-2002)

Weimin, ZOU, lexian YANG, lan JIANG, Shuqin WU, Qi YI, Jianli WU

Distribution of drug resistant luminous bacteria in penaeid shrimp grow-out ponds

Distribution of luminous bacteria (LB) in penaeid shrimp grow-out pond water in semiintensive seawater farming system and their resistance to 15 antibacterials were investigated. Total viable counts and luminous bacterial counts in pond water ranged from 2.00xl03 to 1.35xl04/ml and l.OOxl01 to 8.00Xl02/ml, respectively. The percentage composition of LB in the total viable population increased significantly with period of culture. Five species of LB such as Vibrio fischeri, V. harveyi, V. orientalis, V. splendidus 1 and Photobacterium leiognathi were encountered. V. harveyi was the dominant species, constituting >80% of the total LB. Multiple antibiotic resistance was more common in these LB. Pond water isolates showed resistance to at least four antibacterial agents.

Optimization of dose of methyltestosterone (MT) hormone for sex reversal in tilapia (Oreochromis niloticus L.)

This paper describes the optimization of dose of methyltestosteronei (MT) hormone for masculinization of tilapia (Oreochromis niloticus). Five treatments (i.e. T1 T2, T2, T4 and T5) with different doses such as 0, 40, 50, 60 and 65 mg of MT hormone were mixed with per kg of feed for each treatment and fed the fry four times a day up to satiation for a period of 30 days. The stocking density was maintained 10 spawn/liter of water. The growth of fry at different treatments was recorded weekly and mortality was recorded daily. At the end of hormone feeding the fry were reared in hapas fixed in ponds for another 70 days and at the 100th day the fish were sexed by the gonad squashing and aceto-carmine staining method. The analysis of growth data did not show any significant variation in length and weight of fish among the different treatments. High mortality of fry ranging 66% to 81.6% was observed in different treatments and highest mortality was observed during the first twelve days of the experiment. The sex ratio analysis showed that T2 (40 mg/kg) and T5 (65 mg/kg) produced 93.33% of sex reversed male and T3 (50 mg/kg) and T4 (60 mg/kg) produced 96.66% sex reversed male, and these ratios were significantly (p<0.05) different from 1:1 male: female sex ratio. The control, T1 (0 mg/kg) contained 43.33% male progeny. From these results it is suggested that either 50 mg/kg or 60 mg/kg of MT with a feeding period of 30 days could be considered as an optimum dose for masculinization of tilapia (O. niloticus).

Survey of veterinery [sic] drug residues, environmental contaminants and mycotoxins of cultured shirmp [sic] in Iran

Economical achievement of optimal growth in developing countries may lead to sustainable poverty reduction. Agricultural activities play an important role in economy and human being welfare, which leads to establishment of food security and quality. Aquaculture products in developing countries share 51.4 percent of total agricultural production.7—percent in developed countries. Therefore undoutedly food production by means of quality and quantity has to be increased .The history of shirmp production goes back to 500 years ago. Today 50 countries of the world produce shirmp .In Islamic Republic of Iran shrimp production started since 1992 in the coastal region of Persian Gulf. The shrimp culture farms canbe classified in to 4 different categories; Extensive, semi-extensive, intensive and super instensive. Global ecological manitenanc is one of the major concerns of authorities Human manipulation of nature is the most destructive activity. Industrial sweage leakage in to the rivers and water sources is a big issue that causes reduction in the aquatic population. Heavy metals have an inhibitory effect in the production and growth of sealife. Human intake of food treated with anti microbial cause's allergy, hypersensitivity and develops microbial resistance. Organochlorine compounds contamination may found in hepato pancreatic tissues of aquatic products, Aresnic may transfer to man via plant & animal product contamination. In 1991 during Persian Gulf Mir 700 oil well set