Welfare of fish in aquaculture is an important concern, as it is estimated to impact between 37 and 120 billion individuals every year, and is a growing concern for consumers, producers, interest groups and authorities. Therefore, it is important to investigate real-time stress responses during common aquaculture practices. Star-Oddi DST milli-HRT heart rate and temperature loggers have proved to be useful in this regard, thanks to their capability of measuring heart rate as an indicator of stress in freely swimming fish.

Measuring heart rate as an indicator of stress 
A recent study, conducted by the Swedish University of Agriculture and the University of Gothenburg, evaluated and validated Star-Oddi’s DST milli-HRT, heart rate and temperature logger, for use in rainbow trout (Oncorhynchus mykiss). The study evaluated the effects of common aquaculture practices, such as netting, grouping and enforced activity on the cardiac performance of freely swimming rainbow trout.

Exposure to multiple stressors
The results showed that exposure to multiple stressors without enough recovery times between them, can cause collapse of cardiac scope. This combined with disadvantageous environmental conditions could lead to a raise in mortality. The findings are thus of high importance for the aquaculture industry. 

The paper was published in the journal Aquaculture in May 2019 and can be accessed here.