Performance Assessment of Suture Type, Water Temperature, and Surgeon Skill in Juvenile Chinook Salmon Surgically Implanted with Acoustic Transmitters

This study assessed performance of seven suture types in subyearling Chinook salmon Oncorhynchus tshawytscha implanted with acoustic microtransmitters and held at two water temperatures (12 degrees C and 17 degrees C). Nonabsorbable (Ethilon) and absorbable (Monocryl) monofilament sutures and nonabsorbable (Nurolon and silk) and absorbable (Vicryl, Vicryl Plus, and Vicryl Rapide) braided sutures were used to close incisions in Chinook salmon. When differences existed among suture types, tag and suture retention were generally highest for monofilament sutures. Wound inflammation and ulceration were generally lower for Ethilon and Monocryl than for most of the braided sutures. In this study, Nurolon (braided) often resulted in low wound inflammation and ulceration, although suture retention was poor. Generally, fish held in 12 degrees C water had more desirable postsurgery healing characteristics (i.e., higher tag and suture retention; lower incision openness, wound inflammation, and ulceration) at 7 and 14 d postsurgery than fish held in 17 degrees C water. On days 34 and 63, tag retention remained high among fish in 12 degrees C water, while suture retention decreased dramatically in both water temperatures. We found a significant effect of surgeon on tag and suture retention, wound inflammation and ulceration, and incision openness. Surgeons in this study were initially thought to have similar surgical proficiency based on their extensive previous experience. However, surgeons who had received feedback on their previous surgical technique performed better in this study. Results indicate that surgical training (i.e., feedback) and perhaps aptitude, rather than surgeon experience alone, may be as important as suture type in influencing the retention of sutures and tags. The overall results support the conclusion that Monocryl is the best suture material for closing incisions created during surgical implantation of acoustic microtransmitters in subyearling Chinook salmon. Future research should include testing different suturing patterns and knotting techniques as well as the number of knots required for different incision lengths.