Alewife (Alosa pseudoharengus) invaded the Great Lakes in the early-mid 20th century, and massive die-offs of these fish have been a big smelly problem in Lake Michigan ever since. The Chicago Tribune even has Alewife Awards for the “rankest cultural flotsam and jetsam to hit our shores” which is why I ended up morbidly transfixed by pictures of Honey Boo Boo when I was searching for something small and bothersome. I was not long distracted by such glitter because I was on the trail of a report that notes, rather casually, that there used to be a commercial Alewife harvest in Lake Michigan, but it failed.
A fork in the future
There are essentially two main arguments about harvesting invasive species that we have encountered on invasivore.org, in popular media, and in the scientific community. The first is the popular perception is that harvesting invasive species may save the day, sending Asian Carp and feral pigs the way of the buffalo. The other argument is that if economic values become tightly linked to the invasive population, then the populations may be preserved to maximize those values.
These two futures are a fork in the road for harvesting invasive species, whether harvests add to conservation goals or backfires. For most species this fork hasn’t been reached, but the path of the alewife has been chosen. Alewife of Lake Michigan may provide a glimpse into the future for the harvest of other invasive species.
Alewife and Salmon
The alewife of Lake Michigan didn’t become such a runaway success in the diners and bistros of Chicago that Cubs and White Sox fans joined hands in solidarity for the protection and conservation of a beloved fish. Alewife wasn’t like Grand Banks cod, which according to Mark Kurlansky, shaped the development of the modern world. At least to people. To the salmon of the Great Lakes, the introduction of Alewife saved the day. And in Lake Michigan, salmon is King. No seriously, I caught a 16-lbs Chinook out of there only a few months ago:
Alewife became the major prey of Lake Michigan salmon and the trophic foundation for a billion-dollar fishing industry. Alewife became an economically very valuable resource and preventing collapse of alewife populations to support Chinook harvests are now a major policy objective for Lake Michigan.
The commercial alewife harvest in Lake Michigan wound down as catch quotas and other restrictions which were implemented to recover alewife stocks made the harvests unprofitable. When Alewife came to the fork in the road, the decisions of policy makers and managers were clear: the Alewife stay. Does this mean that they turned their back on conservation?
I think not. By the time the Alewife fishery closed, the lake ecosystem was not a choice between some natural native system and the hodgepodge of introduced non-native and invasive species we see today. The option of the native ecosystem was already long gone. Protecting alewife, invasive or otherwise, increases the value of the ecosystem services now available. Will this be true for all invasive harvests?
Prospects for harvesting other invasive species
We said at the outset that alewife might present a possible future for harvesting invasive species and speak to the potential of harvests as a management option. In this new era where natural resource managers are starting to seriously consider the benefits and risks of harvesting invasive species, alewife in Lake Michigan provide the first data point in the experiment. It doesn’t prove the point one way or the other, though it does validate the real potential for concern, and makes the point that harvesting invasive species is not a silver bullet.
That doesn’t mean alewife aren’t tasty.