The river herring run at Parsonage Creek in Baldwin has been elusive in recent years. While we had anectodal evidence that it existed, we weren't able to document it until 2016. As the following video shows, our difficulty may have been the result of the run's preference for nocturnal migration. While river herring certainly migrate during the day in many instances, we have found that in some cases they prefer to move under the cover of darkness. There's little research on this question, but biologists think it may occur in situations with large concentrations of light-dependant predators, such as comorants or herring gulls.
This video also shows the even a relatively short barrier can be a complete barrier to river herring. While certainly very capable swimmers, they are not jumpers and simply cannot manage a barrier of more than a few inches.