<Poster Session>Effects of anesthesia and surgery on condition of blood in chum salmon, Oncorhynchus keta

Abstract

Telemetry is a valuable technique for elucidating salmon behavior but it is important to establish the time required for recovery before fish can be safely released after anesthesia and surgical attachment of telemetry devices. To ensure that fish swim normally in experiments after surgical tagging, recovery can be determined using indices of stress and blood conditions. This study examined the time course of return to normal of blood parameters of chum salmon following anesthesia and surgical attachment of a telemetry transmitter. Sixteen blood parameters were assessed: pH, pCO2, pO2, BE (Base Excess), HCO3, tCO2, sO2, Lact (Lactate), Na (Sodium), K (Potassium), Cl (Chloride), Glu (Glucose), Hct (Hematocrit), Hgb (Hemoglobin), cortisol and testosterone. Blood was sampled by cannulation to avoid stressing the fish, at the following times after tagging: 0, 3, 6, 12, 24, and 30 h. Values of pCO2, pO2, sO2, Hct, Lact and pH returned to normal after 1–6 h. There were no significant changes in the levels of the stress hormone cortisol during the sampling period. The values of other parameters also did not differ during the sampling period. In light of these findings, chum salmon can be safely released 6 h after transmitter tagging.