• Philipp, David P.
  • Zolderdo, Aaron J.
  • Lawrence, Michael J.
  • Claussen, Julie E.
  • Nowell, Liane
  • Holder, Peter
  • Cooke, Steven J.


In Opinicon Lake, Ontario during two non-pandemic years (2019 and 2022) the hook-wounding rates from recreational angling observed among nesting male largemouth bass Micropterus salmoides (LMB), and nesting male smallmouth bass Micropterus dolomieu (SMB), were quite high, but typical of those observed in the lake over the last 20 years of monitoring. That level of illegal, preseason angling resulted in very low percentages of both LMB and SMB nesting males being successful at raising their broods to independence, rates comparable to those observed for this lake in previous years. In 2020 and 2021, amid the COVID-19 pandemic, however, access to fishing in Ontario was severely limited during the bass spawning season, which serendipitously provided a natural “whole-lake bass spawning sanctuary” to study. Not surprisingly, the hook-wounding rates for nesting male LMB and SMB in Opinicon Lake were the lowest rates ever observed over the last 30 + years. Concomitantly, the percentage of nesting male LMB and SMB that were successful at raising their broods to independence was approximately 3–4 times greater than that in the non-COVID years. Not unexpectedly, those increases in nesting success translated to similar increases in LMB and SMB reproductive success (production of post parental care, independent fry). More importantly, those increases further resulted in large increases in the annual recruitment of both LMB and SMB. This unanticipated COVID-driven experiment revealed that using bass spawning sanctuaries would be more efficient than closed seasons as a management strategy to conserve levels of black bass annual recruitment.


This study was conducted in Opinicon Lake, Ontario (Fig. 1 44°33'33.3"N 76°19'49.3"W), which is a 780-ha mesotrophic lake with a mean depth of 4.9 m and a maximum depth of 9.2 m (Agbeti et al., 1997). Opinicon Lake is part of the Rideau Waterway system and is in the Cataraqui River watershed. Black bass reproduction (both LMB and SMB) was monitored along five shoreline transects that varied from 700 to 1100 m in total length during the spawning seasons of 2019 − 2022 (i.e., before, during, and after the COVID-19 pandemic restrictions). These sites had been identified during previous lake-wide surveys of the entire shoreline as areas representative of the lake as a whole, and where black bass nested in moderate-high density each year. These sites were also projected to be part of a study of bass spawning sanctuaries to be conducted over the following few years as pre-treatment years to gather baseline data for both sanctuary and control sites. The change in fishing pressure caused by the onset of the COVID-19 pandemic, however, canceled those plans, but provided the serendipitous opportunity described herein.