The behaviour of largemouth bass in Lake Opinicon, Ontario: A biological perspective for the evaluation of Murphy Bay Fish Sanctuary

This study provides a biological perspective on the potential of using year-round sanctuaries to protect largemouth bass (Micropterus salmoides). Although the Rideau Lakes bass sanctuaries have been present for more than 70 years, a lack of empirical rationale has resulted in a considerable debate regarding their usefulness. Using radio telemetry in Lake Opinicon, Ontario, the current study indicates that largemouth bass behaviour is influenced by the structural complexity of the habitats they occupy. In high-structure habitats, bass tend to have smaller utilization areas, displacement rates and radial displacements relative to those occupying low-structure habitats. All largemouth bass were captured and released (after transmitter implantation) in high-structure areas; however, more than half (12 of 23) of these individuals made spring (closed fishing season) relocations to low-structure areas where most (11 of 12) remained for the duration of the study. Behaviour is important to consider because of the influence it has on the level of sanctuary protection received by a largemouth bass. Twelve individuals began the study in the high-structure habitats of Lake Opinicon's Murphy Bay fish sanctuary; however, only five remained in high-structure habitats throughout the study to receive full open season protection, two others received partial protection and four largemouth bass received no open season sanctuary protection because they made spring relocations to low-structure areas outside of the sanctuary. The results of this study provide an important biological perspective for the evaluation of year-round bass sanctuaries. Further research is needed to understand the specific causes of observed behaviours and to investigate how open and closed season protection of a year-round sanctuary translates into overall bass fishery benefits. Therefore, we recommend the maintenance of the Rideau Lakes bass sanctuaries as year-round regulations until there is sufficient empirical evidence to support their re-designation or removal.