Comparison of Bi-Directional Knotless and Monofilament Sutures for Wound Closure in Juvenile Chinook Salmon

Acoustic telemetry is widely used for studying the survival and behavior of fish, and utilizes acoustic transmitters that must be externally attached or surgically implanted.  Tag-effect research has focused on minimizing the negative effects of both transmitter presence and the method of attachment.  Surgical intra-coelomic implantation, one such method, is known to potentially affect fish health, behavior, and survival, thus impacting study results.  As new telemetry technologies become available, it is imperative to understand the effects the transmitter and implantation process have on the fish.  We evaluated the performance of suture material, suture techniques and needle size for closing incisions in juvenile Chinook salmon (Oncorhynchus tshawytscha) by examining mortality, transmitter expulsion, incision openness, erythema, and suture functionality.  The first experiment examined bi-directional knotless sutures in three closure patterns compared to monofilament sutures using a single pattern with fish held at 12°C and 17°C.  The second experiment re-evaluated the bi-directional knotless suture by using two needle sizes.  In a third experiment, two types of monofilament were compared to determine if the materials yielded similar performance.  This presentation focuses on the results of these experiments, and summarizes the strengths and weaknesses of each material and approach when used to close incision wounds.