Cooperative Fish and Wildlife Research Units Program: North Carolina Cooperative Fish and Wildlife Research Unit
Education, Research and Technical Assistance for Managing Our Natural Resources

Striped bass Morone saxatilis in inland reservoirs play an important role ecologically and in supporting recreational fishing. To manage these populations, biologists need information about abundance and mortality. Abundance estimates can be used to assess the effectiveness of stocking programs that maintain most reservoir striped bass populations. Mortality estimates can indicate the relative impact of fishing versus natural mortality, and the need for harvest regulation. The purpose of this article is to evaluate tagging studies as a way of obtaining information about abundance and mortality. These approaches can be grouped into three broad categories: tag-recapture, tag-return, and telemetry. Tag-recapture methods are typically used to estimate population size and other demographic parameters, but are often difficult to apply in large systems. A fishing tournament can be an effective way of generating tagging or recapture effort in large systems, compared to using research sampling only. Tag-return methods that rely on angler harvest and catch-and-release can be used to estimate fishing (F) and natural (M) mortality rates and are a practical approach in large reservoirs. The key to success in tag-return studies is to build in auxiliary studies to estimate short-term tagging mortality, short- and long-term tag loss, reporting rate, and mortality associated with catch-and-release. F and M can also be estimated using telemetry tags. Advantages of this approach are that angler non-reporting does not bias estimates and fish with transmitters provide useful ecological data. Cost can be a disadvantage of telemetry studies; thus combining telemetry tags with conventional tag-returns in an integrated analysis is often the optimal approach. In summary, tagging methods can be a powerful tool for assessing the effectiveness of inland striped bass stocking programs and the relative impact of fishing versus natural mortality.