Thermal tolerance, safety margins and vulnerability of coastal species: Projected impact of climate change induced cold water variability in a temperate African region.

Anthropogenic induced climate change is predicted to increase the thermal variability in coastal waters, which can have strong physiological effects on individuals and populations of marine ectotherms. The magnitude and direction of these thermal effects varies depending on species, life stage, biogeography, habitat and season. This study aimed to compare the thermal tolerance of a range of juvenile fish and adult macro-invertebrates from intertidal and estuarine habitats in a warm-temperate, thermally variable region on the south-east coast of South Africa.

The use of internal heart rate loggers in determining cardiac breakpoints of fish.

As marine environments are influenced by global warming there is a need to thoroughly understand the relationship between physiological limits and temperature in fish. One quick screening method of a physiological thermal tipping point is the temperature at which maximum heart rate (ƒ) can no longer scale predictably with warming and is referred to as the Arrhenius break temperature (T). The use of this method has been successful for freshwater fish by using external electrodes to detect an electrocardiogram (ECG), however, the properties of this equipment pose challenges in salt water when evaluating marine fish.

Implantation, orientation and validation of a commercially produced heart-rate logger for use in a perciform teleost fish.

Quantifying how the heart rate of ectothermic organisms responds to environmental conditions (e.g. water temperature) is important information to quantify their sensitivity to environmental change.