Designing for Fish Forage
There are a million pond owners feeding fish, farming them. They buy pellets and load up their fish feeders regularly. And their goal is to grow big fish for folks, especially kids, to catch. There’s a sub-sector that goes beyond this and combines fish feeding stations with great structure, so they have a shot at natural food production too. Many of these folks are eyeing that elusive, world-record largemouth bass. Lot’s of these folks incorporate BioHavens into their design, as the islands are a strategic form of structure that provides both fish food/fish forage and strategic habitat.
Here at Shepherd we focus on three things…we provide lots of structure, with dozens of BioHavens, many of which are experimental designs and some of which do provide unique habitat and forage opportunities. Our BioHaven floating streambeds exemplify this. Consider that a study run at Mississippi State University measured a 19% increase in fish biomass associated with a pond that held a floating streambed, as compared a standard pond. In that case, both ponds were being fed, but the one with the BioHaven streambed saw a nearly 20% bump (see our research section for the Mississippi University study). Here on Fish Fry, we have two streambeds in operation continuously, and they are far bigger than the one in the MSU test.
Beyond strategic BioHaven structure when we converted Fish Fry from a seasonal pond to a perennial lake, we incorporated dozens of structural changes. The lake bottom is varied, and designed so as to maximize for circulation. An example…we screened nearly 11,000 tons of cobble, and positioned it in layers in locations across the pond that experience the greatest fetch…wind. This means that water and the suspended solids in it, and to some extent dissolved solids too, are being moved across the cobble whenever the wind blows. No utility bill!
So you can see two of the primary principals associated with triggering nature’s food web at work here…surface area (structure), combined with circulation…wind and forced air via the BioHaven Streambeds. The third component of our strategy is forage. Of course, surface area and circulation trigger biofilm/periphyton, which is forage. But we keep going with that theme. Here’s some examples of additional design to enhance for forage:
1. Wood, in the form of standing timber, strategically positioned deadheads, and deciduous, seasoned brush piles. The seasoned brush piles stem from what we’ve gleaned from study of Brush Park aquaculture (Azim et al).
2. Cobble and gravel in a variety of configurations and settings, which enhance for a wide range of invertebrate life, including crawfish. Big rock and boulders add to the three dimensional design opportunities.
3. Native perennial weed beds, in both deep and shallow settings. This is a particularly important component. Today we catch lots of fish in both settings.
4. Maximal exposure to “edge.” This achieves two things…it designs for biodiversity, as edge habitat is where biodiversity is greatest. It also provides lots of accessible harvest opportunities. In other words, lots of shoreline access to great fishing sites.
There are several other strategies we employ here, but I’m not going to overload you all in one shot. Suffice to say, the above are the basics. Consider how they differ from a pond with liner with fish feeder. I mean, that can work, sort of. But it can also be a recipe for disaster, as in algae bloom, and ultimately the dissolved oxygen based fish die off.
I was once visiting with Dr. Bruce Condello who experiments in this area himself in a big way. I asked him, in his opinion, which setting is more likely to produce world record fish, a farm setting, or a wild setting? He said “the wild one.” I think he’s right, because the wild setting employs nature’s systems more fully, and they are extremely effective at generating forage. So if you are managing water, consider targeting surface area, circulation, and strategic forage enhancements. When these three come together, you will have a powerful ally…nature herself, pulling in the same direction.