Evaluation of hand-held meters for determination of hemolymph lactate and protein concentrations in red swamp crayfish Procambarus clarkii

We evaluated the accuracy of an Accutrend® lactate meter and a Reichert® Vet 360 temperature compensated refractometer for determining red swamp crayfish Procambarus clarkii (Girard, 1852) hemolymph lactate and protein concentrations, with results compared to measurements obtained from spectrophotometric analyses. Results from the lactate meter (R2=0.926) and refractometer (R2=0.830) both demonstrated strong relationships with spectrophotometer measurements, indicating that these instruments provide rapid, reliable, and economical methods for determining crayfish hemolymph lactate and protein concentrations. Both meters can provide on-site information to commercial crayfish farmers and processors to assess crayfish health and stress levels, and can also provide important biomonitoring data to field biologists as they evaluate the success of water management activities designed to reduce hypoxia and improve habitat conditions for aquatic biota.