Evaluating jail-bar exclusion design for selective passage of turtles and fishes, including invasive common carp (Cyprinus carpio) and endangered spotted gar (Lepisosteus oculatus)
摘要
Managing aquatic invasive species, such as common carp (Cyprinus carpio), is critical to protect and restore native ecosystems, including the at-risk species living in them. This study evaluated jail-bar exclusion to guide the design of an exclusion structure preventing the passage of common carp into newly created coastal wetland habitat expected to provide spawning habitat for the endangered spotted gar (Lepisosteus oculatus). To guide the design and implementation of said exclusion structure, the effects of exclusion on the in-water passage of native fishes and turtles was examined. Fifty sites in Rondeau Bay, Ontario, were sampled in 2023 and 2024 using repeated hoop-net sets with no exclusion (control), and 5 cm, 7 cm, or 9 cm wide exclusion treatments. Although the composition of the native fish and turtle species captured were similar across all treatments, the passage of wide-bodied fishes and turtles with large carapace heights was impacted by the 5 cm and 7 cm exclusions. All common carp and spotted gar that passed the exclusions were greater than length at earliest sexual maturity, with the number of spotted gar captured differing significantly from expected, despite capturing similar mean sizes of spotted gar across all treatments. This experiment was conducted as a result of inter-agency cooperation, which will be required for the successful implementation of jail-bar exclusion.