PNNL

Abstract

Many telemetry based studies require that fish be sampled from the wild and then held for some amount of time both prior to and after the implantation of a transmitter. However, the effects of such holding (or the lack thereof) are often overlooked. Pre-surgical holding often occurs to facilitate logistical needs of research projects and as an attempt to minimize negative physiological effects due to capture and handling stress. Further, post-surgical holding time and conditions greatly influence the physiological state of fish prior to being returned to the wild. This paper reviews pertinent studies pertaining to the effects of surgical holding on the behavior, physiology, and survival of fishes, with particular emphasis on juvenile salmonids. The effects of individual aspects of surgical holding such as stressors, time, holding conditions and water quality are also examined. Recommendations regarding certain aspects of surgical holding (e.g., holding duration) are offered with a goal of reducing bias related to the surgical process. Pre- and post-surgical holding times of 18–36 h are suggested as a general guideline for juvenile salmonids.