Effects of Production Factors on Shrimp Culture in Boushehr, Iran

Shrimp culture in Iran is a rather new industry. It began with feasibility studies in 1989 and the shrimp farms started production in 1992. Shrimp culture is important to the four southern provinces of Iran since it is a major source of employment and a factor in the local economies. A study has been done on the economics of the shrimp culture sector in Iran and data collected from 1999 to 2001. Results show that feed variable is one of the factors important for growth and productivity in shrimp pond. According to the average of results, range for feeding shrimp in farm equal 3.35 to 4.5 ton ha–1 crop–1. According to the standard condition, generally for semi intensive systems and Penaues indicus species feeding should be 2.5 to 3 tons ha-1 crop–1 in every crop cycle. Thus there is an excessive used of feed for the average pond shrimp culture in this case study. Results also show that the number of feeding per day is low which is 2 times day -1. Feeding frequency should be increased to 4 times per day. The best time for feeding is also a factor by best time is around 6:00, 10:00, 18:00 and 20:00 h. Quality of feed is also important in shrimp culture. The average of stocking in the shrimp pond about 223,700 to 305,000 ha–1 or 1.6 to 2.2 m-2 individual larvae which is every low as standard results of larvae per square meter for semi intensive is around 15. The number of aerator used of the farm was 1.5 to 2.05 unit ha-1, which is lower than the standard number used which is around 3-4 aerators ha-1 which will allow more oxygen to be absorbed into the water. According to the results average number of tray number on the pond was 2-3 tray ha-1, which is lower than the standard which is equaled 4-6 ha-1. Tray number is an indicator whether prawn are eating and have enough feed and also whether they are healthy or not which indirectly will affect the pond production. The number of labours on the farm was 7 to 8 or 0.50 to 0.57 person ha–1. An optimum number should be 6 person or 0.36 to 0.43 ha–1 working in the farm is enough. This is for efficiency used of labor existed on farm. Temperature is one of the biological variables on the shrimp pond that is relevant to total productions. According to the results the average temperature in shrimp farms was 29.83 to 31.4 0C. This range of temperature is well for shrimp culture because generally, the range of standard temperature for shrimp culture Penaues indicus species is 28 to 32 0C. According to the results of study, average amount of Oxygen is 2.26 to 2.70 mg L-1. This amount is much lower than 5 mg L–1, which is the optimal level of oxygen in water. Thus, used of more aerators would help to ensure enough oxygen in the culture system. The result also showed pH in the pond ranged from 8.11 to 8.67. Generally, optimal range for pH in the pond is 7.4 to 7.8, but tolerance level is from 7.0 to 9.0. Pond liming may help to buffer the pH in pond. Salinity is a biological variable in the shrimp pond. According to the result, the average salinity is 38.65 to 42.29 ppt, but the normal range for salinity is 33 to 35 ppt. Reduction of salinity to normal range could be achieved by adding fresh water to the pond. The average pond depth range from 127.98 - 136.52 cm but normal range for shrimp pond is around 140 to 200 cm. Thus, shrimp farmer must deepen their pond depth, in order to give shelter from sun and more space for shrimp to grow, thus increase production.

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