Fish species failing to adapt to warming oceans

Biotest study species European perchA research project associated with Sweden’s University of Gothenberg has found the impact from steadily rising ocean temperatures could prove fatal for some fish species. As well as the loss of biodiversity in the world’s oceans, the impact from warming seas on both marine mammals, and human populations that rely heavily on fish as a food source, would also be dramatic.
University of Tasmania senior research fellow Timothy Clark was a member of the Swedish team that conducted tests during 2012 and 2013 on European perch (Perca fluviatilis) from the ‘Biotest’ lake enclosure in the Baltic Sea. For over 30 years, these fish have been subjected to the lake’s ‘elevated’ water temperatures that are heated by the nearby Forsmark nuclear power plant.
The tests were also conducted on ‘reference’ fish populations from outside the enclosure, and results showed that while the fish are able to adapt their resting physiological functions to slowly rising temperatures, their maximum physiological functions are far less flexible.
“The fish can increase their lethal temperature by a certain amount, but they can’t keep up with the current rate of global water temperature increases,” Clark said. Continue reading Fish species failing to adapt to warming oceans

Heat stress: A major contributor to poor animal welfare associated with long-haul live export voyages

Recent investigations by the Australian Department of Agriculture, Fisheries and Forestry into high mortalities on live export voyages from Australia to the Middle East during the Northern hemisphere summer suggest that animal welfare may be compromised by heat stress.

The live export industry has generated a computer model that aims to assess the risk of heat stress and to contain mortality levels on live export ships below certain arbitrary limits.

Although the model must be complied with under Australian law, it is not currently available for independent scientific scrutiny, and there is concern that the model and the mandated space allowances are inadequate. Continue reading Heat stress: A major contributor to poor animal welfare associated with long-haul live export voyages

Overheated herds

This year’s higher than average summer temperatures have highlighted a growing animal welfare issue for the US livestock industry, and it is one that will prove equally relevant for Australia’s farmers as we head into warmer weather. Cattle prefer a cool climate, and suffer heat stress when they become too hot. If symptoms of the animals’ discomfort go unrecognised, a dairy cow’s milk production and fertility can be affected, while the result for intensively farmed beef cattle may be growth and weight loss, which leads to reduced meat production.

As some of the physiological responses to excessive heat are experienced internally by cows, and therefore less likely to be noticed until the animals are severely affected, livestock researchers from the University of Arizona, led by dairy specialist Robert Collier, have developed a vaginal sensor that can measure a cow’s core body temperature, and a leg sensor able to determine whether the cow had been sitting or standing. Continue reading Overheated herds