First Draft: Assessing the impact of Muskellunge predation on Smallmouth Bass in the New River, Virginia

Assessing the impact of Muskellunge predation on Smallmouth Bass in the New River, Virginia

I am creating a flier with a QR code (a code that can be scanned with your phone) linked to a 5-minute video detailing the results of my project on Muskellunge and Smallmouth Bass in the New River. The video will describe the predatory impact that Muskellunge have on Smallmouth Bass as well as the management implications that predation has on the Smallmouth Bass fishery. Below is an outline for that video:

Introduction

The ‘Monster Muskie’ – a historical context

  • Description of the dislike and fear that often accompany Muskellunge and other members of the esocid family
    • Quote from previous AFS president
  • Where does this aversion come from?
    • Resource-users are afraid that they are ‘eating machines’
      • Quotes from New River fishermen
    • Muskellunge will prey on other sportfish and decimate quality fisheries
  • This fear of Muskellunge and their impact sometimes leads to anglers taking matters into their own hands
    • Include a snippet of guy killing Muskie in Michigan
    • Quote from Minnesota article

The ‘Monster Muskie’ – scientifically speaking

  • What does Muskellunge diet and predation actually look like?
    • Discuss diet studies from Wisconsin, Michigan, Minnesota
    • Generally Muskellunge prefer ‘softer’ prey (e.g. Suckers, Minnows, Gizzard Shad)
    • And there are many instances of successful fisheries with both Muskellunge and Smallmouth Bass (e.g. St. Lawrence River)
  • HOWEVER – some evidence exists for predation on less-preferred “spiny fishes,” when preferred forage is lacking
    • This can happen when there is a decrease in preferred forage or when there is a substantial increase in the number of consumers
    • Describe predation on Largemouth Bass, Smallmouth Bass, and Walleye in other systems

How this applies to the New River

  • Previous New River diet study – consumption of Smallmouth Bass by Muskellunge was very low
  • But then the regulations for Muskellunge changed and now there are more Muskellunge and complaints of decreasing catches of Smallmouth Bass
  • So, are there enough Muskellunge so that now Smallmouth Bass have become a more important part of their diet? How was consumption changed?
  • We set out to answer that question!
    • Pumped a lot of Muskellunge stomachs
      • Throughout the year
      • And throughout the New River
    • Sifted through a lot of Muskellunge puke
    • Found very little Smallmouth Bass – pie charts with diet composition
    • Conclusion – not a very important part of their diet!
  • But, what about the fact that there are more Muskie out there? Even if they eat only a little of Smallmouth Bass, couldn’t it be a lot overall?
  • We set out to answer that question too!
    • We estimated how much an average adult Muskellunge eats annually
    • Then, we estimated how much of that is Smallmouth Bass annually
    • We have an estimate of how many Muskie there are at each site, so then we multiply that consumption by how many Muskie there are, and we have the number of Smallmouth Bass consumed by Muskellunge
    • We also have an estimate of how many Smallmouth Bass there are at each site
    • This is how they compare! Conclusion – it’s very unlikely Muskellunge are having a substantial impact on Smallmouth Bass

What does it all mean?

The Smallmouth Bass population has seen some declines in catches of slot-sized fish over the last few years. If Muskie are not the cause, then what is?

  • Increased fishing pressure
    • VDGIF estimates 60% increase
    • There’s also been an increase in bass tournaments
  • Variable recruitment
    • Water flow and Claytor Dam

Demographic trends over the next few years will hopefully help us figure out exactly what is causing the declines in certain sizes of Smallmouth Bass.

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