Smelt vital to Moosehead Lake game fish population

By Tim Obrey
IF&W Regional Fisheries Biologist

    We pay close attention to the smelt population in Moosehead Lake.
    Smelt are the most important forage item for both togue and salmon.

    Each winter, we take hundreds of stomachs from fish we check on the ice and we examine the contents.
    Over the past 40 years, we’ve been able to develop an extensive archive of food habits data. It is easy to just say “this fish looks skinny” or “this fish is in good shape” but this cursory approach lends itself to drawing incorrect conclusions based on a few rough observations and impressions. Instead, we measure and record this information from large sample sizes and this allows us to get a good look at what is happening lake-wide over long periods of time.
    Smelt are notorious for having up and down years, strong age groups and weak age groups, and when populations crash it can take years to correct.
    Moosehead Lake could be the poster child for this scenario. We had a serious decline in the early 1990’s in our smelt abundance and we are still fighting to get out of that hole.
    We have made significant strides over the last seven years by reducing the number of small togue in the lake that was suppressing the smelt population.
    The smelt responded positively, and growth of salmon and togue improved steadily from 2008-2013 after implementing a no size or bag limit on togue less than 18 inches.
    However, Mother Nature threw us a curve ball in 2013. In most years, the number of young smelt in the stomachs has been around 50-75 percent of the sample. In 2013, it was just 19 percent.
    Despite all the efforts to boost the smelt population, something in the environment caused poor survival for this year class. We documented the decline in the amount of food in togue stomachs and the result was a decline in togue and salmon growth rates.
    When we have a poor age group in a fish population, it is like throwing a rock in calm pond. The effects can ripple on, sometimes for years.
    When this poor age group matures and returns to spawn there may be few adults left to deposit/fertilize eggs, thus creating the likelihood for another weak age class, and so on. This winter we have not seen any older smelt in the stomachs.
    In fact, 100 percent of the smelt in the togue stomachs in 2015 have been hatched this past spring. The good news is that the conditions this past spring must have been favorable for smelt survival.
    The volume of food is still lower than we would like, but growth rates for salmon and togue have shown signs of improvement this winter.
    This spring we are planning some new projects on Moosehead Lake that will hopefully shed some light on the smelt year class failures/successes.
    In most cases, there is nothing we can do to prevent these naturally occurring events. But we can try to react and keep our predator numbers under control to maintain acceptable growth of our game fish.