Sabuj Kanti Mazumder

Effects of temperature and diet on length-weight relationship and condition factor of the juvenile Malabar blood snapper (Lutjanus malabaricus Bloch & Schneider, 1801)

In this study we aimed to analyze the effects of water temperature and diet on the length-weight relationship and condition of juvenile Malabar blood snapper Lutjanus malabaricus over a 30-d experimental period. The experiment was conducted in the laboratory using a flow-through-sea-water system. The fish were subjected to four different temperatures (22, 26, 30, and 34 °C) and two diets (commercial pellet and natural shrimp). Fish were fed twice daily. L. malabaricus exhibited negative allometric growth (b<3) at the beginning of the experiment (Day 0) at all temperatures and both diets except for 22 °C fed with shrimp, which showed isometric growth (b=3). Conversely, at the end of the experiment (Day 30) fish showed isometric growth (b=3) at 30 °C fed with the pellet diet, indicating that the shape of the fish did not change with increasing weight and length, and a positive allometric growth (b>3) at 30 °C fed with shrimp diet, which indicated that fish weight increases faster than their length. The rest of the temperatures represented negative allometric growth (b<3) on both diet, meaning that fish became lighter with increasing size. The condition factors in the initial and final measurements were greater than 1, indicating the state of health of the fish, except for those fed on a pellet diet at 34 °C. However, the best condition was obtained at 30 °C on both diets. Nevertheless, diets did not have a significant effect on growth and condition of juvenile L. malabaricus. The data obtained from this study suggested culturing L. malabaricus at 30 °C and feeding on the pellet or shrimp diet, which will optimize the overall production and condition of this commercially important fish species.摘要目的分析水温度和喂食对摩拉吧笛鲷体长体重关系和肥满度的影响。创新点本研究采用条件可控的流通式海水系统,对摩拉吧笛鲷的体长体重关系和肥满度进行研究。方法本研究使用流通式海水系统在实验室中实施,选取4 种不同温度(22、26、30 和34 °C)和2 种饮食条件(商业颗粒和自然虾米),每天喂食2次,比较鲷鱼体长体重关系和肥满度差异。结论结果表明,摩拉吧笛鲷的最好饲养条件是30 °C,而喂食种类对摩拉吧笛鲷的生长和肥满度的影响没有显著差异。本研究提供了温度和饮食对摩拉吧笛鲷体长体重关系和肥满度影响的基本信息,可用于该物种的生理状态评估。

Water and sediment quality parameters in the Chalan Beel, the largest wetland of Bangladesh*

A study was conducted to investigate the status of the water and sediment quality in the Chalan Beel-a major fresh water fish reservoir of the country for a period of one year from July 2007 to June 2008. The mean values of water quality parameters (depth: 214.73±152.22 cm, temperature 27.68±4.26°C, transparency 123±82 cm, pH 9.7±0.47, total alkalinity 137±42 mg/L, conductivity 307±147 μs/cm, total dissolved solids 183±89 mg/L, ammonia-N 0.27±0.39 mg/L, nitrate-N 0.09±0.07 mg/L, phosphate-P 2.01±2.53 mg/L) and sediment quality parameters (pH 7.21±0.35, organic matter 2.59±0.52%, total nitrogen 0.09±0.04%, available phosphorus 5.4±3.6 Meq./100 g and exchangeable potassium 0.43±0.14 Meq./100 g) were within the range recommended for most of the inland fishes of Bangladesh. Although the water and sediment quality parameters except ammonia and phosphate are in the suitable range, the overall results suggest that better management techniques should be practiced in order to overcome the declining trend of associated aquatic life (fauna and flora) of this important fresh water body of Bangladesh.

The effects of temperature on gastric emptying time of malabar blood snapper (Lutjanus malabaricus, Bloch & Schneider 1801) using X-radiography technique

Water temperature can influence the metabolic rate of ectothermal animal such as, fish. This study aims to investigate the gastric emptying time (GET) of malabar blood snapper (L. malabaricus) at different temperature (22, 26, 30, 34°C) fed with commercial diet pellet. The gastric emptying times at different temperatures were determined X-radiographically, using barium sulfate (BaSO4) as a contrast medium food marker. The food marker and X-radiography showed that initial voidance of fecal matter began 4-8 h after feeding at all temperature. The fastest GET (18 h) was obsereved at 30°C, whereas the longest (28 h) GET was seen at 22°C. GET was increased with increasing temperature up to 30°C whereas decreased at extreme (34°C) and stress temperature (22°C). The findings of this study suggest to culture L. malabaricus at 26-30°C with commercial diet pellet as this temperature ranges escalate the faster digestion process which may contribute faster growth rate of this commercially important fish species. Overall, the data obtained from this study may have important consequences for optimization of commercial production of malabar blood snapper.Water temperature can influence the metabolic rate of ectothermal animal such as, fish. This study aims to investigate the gastric emptying time (GET) of malabar blood snapper (L. malabaricus) at different temperature (22, 26, 30, 34°C) fed with commercial diet pellet. The gastric emptying times at different temperatures were determined X-radiographically, using barium sulfate (BaSO4) as a contrast medium food marker. The food marker and X-radiography showed that initial voidance of fecal matter began 4-8 h after feeding at all temperature. The fastest GET (18 h) was obsereved at 30°C, whereas the longest (28 h) GET was seen at 22°C. GET was increased with increasing temperature up to 30°C whereas decreased at extreme (34°C) and stress temperature (22°C). The findings of this study suggest to culture L. malabaricus at 26-30°C with commercial diet pellet as this temperature ranges escalate the faster digestion process which may contribute faster growth rate of this commercially important fish species. Over...

Present status of Aqua-medicines Used for Fish Culture at Shantahar and Adamdighi of Bogra District, Bangladesh

In order to investigate the present status of aqua-medicines used in various aquaculture activities in Bogra district, Bangladesh a survey was conducted with fish farmers and representative of pharmaceutical companies from December, 2011- to May, 2012 (180 days). The study showed that fish farmers were found to be used a wide range of aqua-medicines for aqua health management and for pond and water quality management . Zeo-fish, Zeo-prime, Ecolite, Megazeo plus etc. Tesmin, Emsen, Polgard, Virex are widely used toxic gas remover. Other than these, farmers were found to use several traditional aqua-medicines for aqua-health management, those included Potassium permanganate, Formalin, Salt, Lime, Melathion, Bleaching powder etc. Forty pharmaceutical companies have been recorded to market these products. Most of the products have been marketed from different countries like USA, Thailand, Malaysia, Belgium and China. Prices were variable, but seemed to be affordable by the aqua farmers. The present investigation pointed out several constraints associated with the use of such aqua-medicines, including lack of technical knowledge of farmers about use of aqua-medicines.