How Do Spawning Benches Work?

Spawning Bench or half-log. (C) Eric Engbretson

In northern states, fish managers sometimes use spawning benches to promote the spawning of smallmouth bass.  While largemouth bass, rock bass, and sometimes bluegill also use spawning benches, it is the spawning of smallmouth bass that inspired the design. 

 

In a healthy lake, smallmouth bass build spawning nests against rocks, sunken trees, or large pieces of wood in about four to ten feet of water.  Next to these structures, the male excavates a shallow, circular crater in the lake bottom.  This system provides good natural protection to eggs and fry. 

 

But in lakes without coarse woody habitat, large rocks or similar objects, smallmouth bass may be forced to construct their nests out in the open.  When spawning and is over and the female has deposited her eggs in the nest, the male diligently guards the eggs and later the fry from predatory fish and crayfish.  When the nests are out in the open without natural protection, the male must guard up to 360 degrees of the crater he has dug.  This is exhausting and dangerous, since his back is always turned away from part of the nest.  Far fewer eggs incubate, and far fewer fry survive their first few weeks when fish have to use nests that lack the natural shield of a habitat's woody elements. 

 

Fish managers have studied the hard work put in by bass and have noted the decreased recruitment of young fish.  The managers came up with an idea for a simple structure they hoped would meet the needs of nesting fish and make it easier for eggs and fry to survive.  The idea for spawning benches was born. 

 

A spawning bench consists of a four to six foot piece of log sawed lengthwise in half and attached to concrete or cinder blocks on each end.  Spawning benches are therefore sometimes called half-logs.  Once placed on the suitable substrate, the spawning bench provides overhead cover from birds of prey.  The concrete blocks on each end protect the nest from raiders on two sides. 

Smallmouth bass guarding nest built adjacent to one of the concrete blocks of a spawning bench. (c) Eric Engbretson

It was a sound design and one that smallmouth bass readily used, but not exactly as intended.  It turned out that smallmouth bass weren't concerned about overhead cover. The benches usually sat in water deep enough to preclude threats from above by ospreys and other birds of prey.  While nests are occasionally built between the two concrete blocks as the designers intended, smallmouth bass usually construct nests next to one side or the other, thus allowing the male to guard the nest from only three sides.  The key element seems to be the concrete block itself and not so much the half log.  In fact, if the spawning bench falls on its side, it still provides excellent protection. 

 

Spawning benches are poor substitutes for the naturally occurring woody cover that fish prefer.  But in lakes devoid of suitable wood, rocks, or trees, spawning benches provide a superb means of helping smallmouth bass defend their nests and allowing more of their offspring to survive.

Artificial Fish Habitat or Fish Attractors: Which Do Fish Need and Why?

​Artificial Fish Habitat or Fish Attractors: Which Do The Fish Need and Why?  First of its kind comparison of artificial fish attractors and artificial fish habitat, explaining what works best for fish reproduction, protection and sustainability of fisheries.


Newly placed, this Fishiding High Rise model towers 12 feet off the lake floor and will soon become a haven for fish in lakes where natural cover is at a premium.  (C)Eric Engbretson Photo

Fishiding Leads the Way in Artificial Fish Habitat-Designed By Fish, For Fish

Newly placed, this Fishiding High Rise model towers 12 feet off the lake floor and will soon become a haven for fish in lakes where natural cover is at a premium.  (C)Eric Engbretson Photo

Artificial fish habitat structures are becoming more popular today.  They're being used more and more, especially in large southern reservoirs devoid of important structure fish need.  Fish managers have traditionally placed bundles of Christmas trees or cedar trees on the lake bottom to try to provide cover for fish.  While effective, the lifespan of tree bundles or brush piles is limited, so replenishing them has always been an ongoing and expensive process.  Today, artificial habitat structures are gaining popularity because they don't decay or deteriorate. 

Of all the outfits manufacturing artificial habitat, David Ewald's Wonder Lake, IL company Fishiding, is ahead of all others, at least if you ask the fish, which is what David does.  Ewald has recently introduced his latest models:  The High Rise.  Ranging in height from 8 to 14 feet, these new designs are the only artificial fish habitat on the market today that incorporate the vertical element.  They tower off the lake floor and provide legitimate structure for fish, unlike his competitors who largely manufacture small and short structures that are inconspicuous to fish and do little to provide them with the kind of cover they're looking for.  The vertical dimension used in Ewald's High Rise models gives fish a range or depth at which to stage, and mimics the effectiveness of sunken vertical timber.      

Ewald's company, Fishiding sells a variety of different fish habitat structures that continue to evolve.  The reason for this is repeated testing.  Ewald monitors test structures over time and modifies them based on how fish respond to them.  The prototypes that don't attract as many fish are retooled and modified until they do or even scrapped altogether.  In effect, the fish vote, and new habitat is designed based on the observed preferences of fish.  No other artificial habitat structures are custom made for fish preferences the way Fishiding is.  When Ewald learned about the often overlooked but highly important vertical dimension, he got to work designing new models that would address this important fish preference and give fish what they want.  The result is his High Rise line of structures.  "Fishiding's artificial fish structures are designed not by what we think will be effective, but what they fish tell us they prefer", says Ewald.

For more information on Fishiding structures or the innovative High Rise models, click on this link, or go to http://www.fishiding.com/

How Do Spawning Benches Work?

Spawning Bench or half-log. (C) Eric Engbretson



In northern states, fish managers sometimes use spawning benches to promote the spawning of smallmouth bass.  While largemouth bass, rock bass, and sometimes bluegill also use spawning benches, it is the spawning of smallmouth bass that inspired the design. 

 

In a healthy lake, smallmouth bass build spawning nests against rocks, sunken trees, or large pieces of wood in about four to ten feet of water.  Next to these structures, the male excavates a shallow, circular crater in the lake bottom.  This system provides good natural protection to eggs and fry. 

 

But in lakes without coarse woody habitat, large rocks or similar objects, smallmouth bass may be forced to construct their nests out in the open.  When spawning and is over and the female has deposited her eggs in the nest, the male diligently guards the eggs and later the fry from predatory fish and crayfish.  When the nests are out in the open without natural protection, the male must guard up to 360 degrees of the crater he has dug.  This is exhausting and dangerous, since his back is always turned away from part of the nest.  Far fewer eggs incubate, and far fewer fry survive their first few weeks when fish have to use nests that lack the natural shield of a habitat's woody elements. 

 

Fish managers have studied the hard work put in by bass and have noted the decreased recruitment of young fish.  The managers came up with an idea for a simple structure they hoped would meet the needs of nesting fish and make it easier for eggs and fry to survive.  The idea for spawning benches was born. 

 

A spawning bench consists of a four to six foot piece of log sawed lengthwise in half and attached to concrete or cinder blocks on each end.  Spawning benches are therefore sometimes called half-logs.  Once placed on the suitable substrate, the spawning bench provides overhead cover from birds of prey.  The concrete blocks on each end protect the nest from raiders on two sides.

 

Smallmouth bass guarding nest built adjacent to one of the concrete blocks of a spawning bench. (c) Eric Engbretson

 

It was a sound design and one that smallmouth bass readily used, but not exactly as intended.  It turned out that smallmouth bass weren't concerned about overhead cover. The benches usually sat in water deep enough to preclude threats from above by ospreys and other birds of prey.  While nests are occasionally built between the two concrete blocks as the designers intended, smallmouth bass usually construct nests next to one side or the other, thus allowing the male to guard the nest from only three sides.  The key element seems to be the concrete block itself and not so much the half log.  In fact, if the spawning bench falls on its side, it still provides excellent protection. 

 

Spawning benches are poor substitutes for the naturally occurring woody cover that fish prefer.  But in lakes devoid of suitable wood, rocks, or trees, spawning benches provide a superb means of helping smallmouth bass defend their nests and allowing more of their offspring to survive.