Temperature stress

TEMPERATURE STRESS

  • Absolute temperature ranges for fish species do not exist because temperature tolerance depends on several factors, including the temperature to which the individual have been exposed, salinity, life stage and reproductive status. Thus, it is difficult to generalize about temperature tolerance because it is influenced by so many factors.
  • Most fish seems to tolerate rapid drop in temperature better than equivalent raise in temperature. This is probably due to the physiological changes that occur within increasing temperature, metabolic rate. However, oxygen is less soluble at high temperature.

Hypothermia and Hyperthermia

  • Hypothermia - Because fish are cold-blooded animals, their activity depends on temperature. Thus at low temperature, fish becomes inactive and depressed. Fish exposed to suboptimal temperature are especially sustainable to water hold infections. Low temperature have been associated with an idiopathic syndrome also known as winter kill.
  • Hyperthermia - It can be a serious problem in salomids when temperature in some culture system may approach their upper lethal limits such as during summer.

Diagnosis of temperature stress

  • As with dissolved oxygen, water temperature can only be accurately measured at the site using a thermometer.

Treatment and prevention

  • Temperature control is feasible in small, closed system (eg. aquaria). But, in ponds or other culture systems with large volumes of water, temperature is usually economically unfeasible to control. Some tropical fish farmer use plastic sheeting to insulate ponds during cold snaps, but this is not practical  for fish ponds. In flow–through systems, temperature control is only feasible when either recycling most of the water or when egg incubation system that use very little water are employed.
Last modified: Friday, 16 September 2011, 11:42 AM