Alewife populations and salmonid stocking numbers have been a sizzling subject ever since back-to-back chilly winters in 2013 and 2014 prompted considerations of a doable prey inhabitants collapse.
Every April, scientists from Ontario’s Ministry of Natural Resources and Forestry (MNRF) and New
York’s Department of Environmental Conservation (NYDEC) full a bottom-trawl pattern of Lake
Ontario’s pelagic prey populations. They drag nets and gather acoustic knowledge at areas throughout the
lake. The knowledge gives a sign of the dimensions and age lessons of alewife, and consequently, how
greatest to handle predator species stocking.
To cut back the strain on depleted alewife populations, the MNRF and New York’s NYDEC made adjustments to salmonid (lake trout and salmon) stocking, beginning in 2017 and 2018 with a 20% discount. In 2019 and 2020, a further 20% minimize in chinook stocking numbers was made, adopted by no additional reductions in 2021, and a ten% improve in 2022.
This previous spring, it was initially believed {that a} sturdy yr class of 2020 alewife would supply a major biomass improve in 2022 and 2023. However, upon additional investigation, scientists discovered there was a higher-than-expected mortality of these two-year-old alewife, presumably due to heavy predation from salmonids.
Although this isn’t as optimistic as as soon as thought, MNRF Lake Manager Andy Todd famous the MNRF would adapt to the brand new findings and mentioned: “We have a rock-solid science program that is tracking lake-wide prey fish so we can work on solutions from an informed position.”
To learn the Great Lake Fishery Commission’s 2022 report, click on right here