Comparative assessment of blood biochemistry and haematology normal ranges between Chinook salmon (Oncorhynchus tshawytscha) from seawater and freshwater farms

Abstract Blood biochemistry and haematological parameters in fish are affected by environmental changes, nutritional status, stress and health. As such, they are useful indicators of fish health and welfare. However, the correct interpretation of these parameters depends on the availability of species-specific reference values. This study provides baseline data and reference ranges for 28 blood biochemistry and haematological indicators for presumed healthy Chinook salmon, Oncorhynchus tshawytscha, including a comparison of the normal ranges of individuals sampled from freshwater and seawater farms in New Zealand. We found significant differences between the two environments for some parameters, including haematocrit, haemoglobin, sodium, chloride, potassium, globulin, cholesterol, haptoglobin and enzymes including alkaline phosphatase, aspartate aminotransferase and creatinine phosphokinase. We also found that some parameters were significantly correlated with fish size, and in some cases, this relationship was also affected by the environment where the fish was farmed. Our results are an important step forward in developing blood biochemistry and haematology tools to assess the health status of farmed Chinook salmon in New Zealand.