Coastal Aquaculture and Mariculture (2+1)

Unit 4 - Water and soil quality management

4.1.1.a. Temperature

• Water temperature has the greatest effect on fish since they are poikilotherms.
• It is impractical to control temperature in ponds and other farming facilities; therefore, large-scale mariculture and coastal aquaculture must be conducted in geographical regions having sufficiently long growing seasons to produce marketable sized fish in reasonable amount of time.
• Temperature also affects oxygen solubility and causes interactions of several other water quality parameters.
• Water temperatures greatly influence physiological processes such as respiration rate, efficiency of feeding and assimilation, growth, behavior and reproduction.
• A temperature increase of 10oC will generally cause rate of chemical and biological reactions to double or triple. Because of this dissolved oxygen requirements are more critical in warm water than in cold water.
• Each species has an optimum temperature and upper and lower temperature limits beyond which it cannot survive.
• Within a species’ tolerable limits growth will increase with increasing temperature and reach a peak beyond which it will decline just before reaching the upper lethal limit.
• Fish will also be healthiest at it optimum temperature. Optimum temperatures vary from species to species and must be considered before choosing a species for culture in a particular geographic location.