Field Notes
U.S. Fish & Wildlife Service
Field Notes Entry   
Flathead Futures
Midwest Region, September 20, 2007
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Biologist Jennifer Johnson poses with a gravid female flathead catfish collected in Tate Island Chute.
- FWS photo
Biologist Jennifer Johnson poses with a gravid female flathead catfish collected in Tate Island Chute.

- FWS photo

- Photo Credit: n/a
Fish Biologist Jeff Finley displays juvinile flathead catfish collected while electrofishing on the Lower Missouri River. 
- FWS photo
Fish Biologist Jeff Finley displays juvinile flathead catfish collected while electrofishing on the Lower Missouri River.

- FWS photo

- Photo Credit: n/a

From their potential to reach leviathan lengths to their laid back attitude, the flathead catfish has long been one of my favorite fish species. An aggressive piscivor (fish eater), these predators are king of the watery jungle we call the Big Muddy.  I’ve worked and fished on the Missouri River over a decade.  I say with confidence the future of flathead catfish populations is looking strong because we are addressing management alternatives and restoring key habitats.  Let’s take a moment to look back and see how flathead management has progressed.

Following the closing of commercial catfishing on the Missouri River in 1992 flathead populations have continued to grow in number and size.  According to several popular fishing organizations, the Big Muddy is now touted as one of our Nation’s primer catfisheries.  The question I pose as a biologist is this, “if it is this good now, what was the Missouri River like prior to the severe habitat loss over the past 50 years?” and, more importantly, “how much better can it get?”  Historic accounts of catfish exceeding 200 pounds were common in early writings about the Missouri and Mississippi river.  Hindsight is always 20/20 and with few scientifically defensible records we can speculate about the past and get nowhere fast.  Now let’s look to the future- flathead futures – and learn what state and federal organizations are doing to conserve and support this species.

Currently the Missouri Department of Conservation is preparing to implement special catfish regulations on a designated reach of the Missouri River.  Angler data collected by the Department shows most flatheads are harvested before they reach 20 inches and 5 lbs leaving fewer fish to grow to trophy sizes of 55 to 70 lbs.  They have held public meetings along the proposed stretch of the river to obtain angler’s oppinions.  MDC feels that limiting the take of fish over 30 inches will improve the population.  While this proposed regulation change would undoubtedly help bolster flathead populations, it only addresses the current population and not the management of their environment. We must look not only at the product of the river also at its processes.  Here is some insight as to what is taking place in the present to adress the processes of the Big Muddy. 

Providing a better natural environment in terms of flow, habitat and food is another part of managing riverine fish populations. The majority of the Lower Missouri River is a swift and deep navigation channel designed to self scour between the confines of rock armored banks.  This is not the favored habitat for the lazy flathead.  They prefer moderate to minimum flow with lots of structure.  If river flows are favorable for spawning in the spring and early summer, the resulting young flathead hatch thrives. 

They feed on insects that occupy the rocky bank lines and rip rap structures.  However, in 2 to 3 years their diet shifts from invertebrates to small fish. They now need to find areas where they can avoid expending excess energy fighting strong water currents and more on feeding in areas abundant with minnows and small fish.  In the same way we deposit used Christmas trees in old reservoirs to restore lost habitat, we must also seek to restore habitat in an altered river. 

This is exactly what the U.S. Army Corps of Engineers Missouri River Mitigation Project addresses; habitat loss along the lower 735 miles of the Missouri River. The project is designed to compensate for aquatic habitat losses resulting from past channelization efforts and restore historic river features.  A primary aspect of the project is the creation and reopening of side channels or “chutes”. 

Additional habitat improvement projects include the alteration of navigation structures to diversify habitats along the bank line and create “off channel” aquatic habitats similar to the historic braided river.  These areas have slower water velocities, more resting habitats and the aggregation of small fishes. 

Flatheads occupy deep pools during the day and move into this shallow water and off channel habitats at night to feed.  Recent studies by the Missouri Department of Conservation demonstrated that most flatheads (80%) travel less than 5 km (V. H. Travnichek (2004)).

Using this information we’ve learned flatheads need a diversity of habitats in close proximity to each other.  This complexity is the primary goal for the creation of side channels and instream structure modifications.

Now begs the question, “are flatheads using it?”  Our observations began in 2005 while monitoring fish populations within four side channels created and maintained under the Mitigation Program.  We selected four chutes: a historic chute, a naturally created chute, and two engineered chutes (one less than five years old and one greater) for a three year study.  We are observing an increasing trend in young flatheads. 

A strong year class of fish is evident in our samples demonstrating a successful spawn in 2001.  During that year discharges were from 100,000 to 155,000 cfs (cubic feet per second) in May and June, inundating more areas of floodplain and shoreline habitat for spawning.  In 2005 the majority of flatheads we collected were around 250 mm (10 inches) in length. 

In most Midwestern rivers flatheads reach this length in their 3rd to 4th  year supporting the suspected spawn in 2001.  In 2005 , 94% of our flathead catch in the side channels between April and October was from this year class.  In 2006, it was 93% and, with two more months of sampling still to come, we collected 85% of the 2001 spawn this year. 

Retaining this proportion of the population in these side channels says something about what they provide.  What excites me about these chutes is that we are retaining a strong year class and recruiting fish from subsuquent year classes selecting to use these side channel habitats.

In addition to favorable habitat for sub-adult flatheads, we are also finding adult flatheads like the chutes too.  In May of this year our crews collected over 300 lbs of flathead catfish in a single 4’ hoop net including one fish weighing 79 lbs. 

Perhaps this was just a lucky net, but it still had 300 lbs of flatheads!  We have seen trophy sized flahead catch rates increase as well with more fish measuring up to 40 inches and weighing over 40 lbs being collected every year.  This increase is likely attributed to the amount of diversity found in the mature chutes and permanent woody debris (snags, or old trees partially burried in the mud) that adult fish use for ambushing prey and spawning.

Contact Info: Larry Dean, 612-713-5312, Larry_Dean@fws.gov
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