Understanding Pre-Spawn Smallmouth

Fly Fishing for Bass in Oregon  & SW Washington Waters

Discover the best times and locations for pre-spawn smallmouth bass fishing in Oregon. Learn about water temperature patterns, fish behavior, and prime fishing spots for trophy smallmouth.

Oregon and Washington boast some great fly fishing opportunities for largemouth, smallmouth, and striped bass, and in this article we are covering the most exciting time in smallmouth bass fly fishing, pre-spawn.

Identifying Smallmouth Bass Versus Largemouth Bass

There can often be confusion in differentiating smallmouth from largemouth bass, so let's begin with the distinguishing characteristics between the two species.

Now that we can properly identify smallmouth bass, it's time to get into the nuts and bolts of targeting smallmouth bass during pre-spawn.  We will address post-spawn in another blog post in the near future.

Water Temperature Patterns Leading to Pre-Spawn

Smallmouth bass begin stirring when water temperatures reach 45°F, typically occurring between April and mid-June in the Pacific Northwest

• Pre-spawn activity intensifies as temperatures approach 50°F
• Optimal pre-spawn water temperatures range from upper 40s to upper 50s (48-58°F)
• Fish become most active in preparation for spawning when waters reach 60°F

Pre-Spawn Location Patterns and Fish Behavior

• Bass move from deeper winter holdings to transitional staging areas
• Look for transition points in depth and structure
• Fish concentrate near:
  • Channel banks
  • Grass flats
  • Steep banks
  • Points and drops
  • Areas with direct access to sunlight

Why Pre-Spawn Bass Are Larger

• Increased feeding activity to build energy reserves for spawning
• Female bass carrying egg sacs
• Concentrated feeding on high-protein forage
• Biological preparation for the spawning period

Prime Oregon Smallmouth Bass Pre-Spawn Locations

Willamette River & Tributaries: Focus on deeper holes near spawning flats

Columbia River & Tributaries: Target rocky transitions and warming bays

Deschutes River Mouth: Look for protected coves and rocky structure

John Day River: Focus on areas with gradual depth changes

Spawning Site Selection Patterns

Males seek areas with:

• Gravel or sandy bottom composition
• Protection from strong currents
• Nearby deeper water access
• Rock or boulder structure
• Water depths between 2-20 feet
• Northwest-facing banks (warm first in spring)

Fly Fishing Gear for Smallmouth Bass

If you are new to fly fishing for smallmouth bass, cast out all previous trout knowledge of fly fishing gear.  Between the flies, lines, and the species itself, we will be fishing larger fly gear.  We have many different prices points of gear to help you have success.

Poppers

For fishing top water patterns we prefer 6WT-7WT fly rods like the Redington Predator or Echo 84-B paired with a Redington Behmoth or Redington Grande Reels and Scientific Anglers Bass Bug floating fly line.

Streamers

The "bugs" we use for streamer fishing can vary in size, but our team really prefers to fish large streamers to target the larger more aggressive bass.  With our setups we are still stripping the streamers and utilizing line of sight on the fly to see the take.  You will want good polarized glasses and heavier setups with a good double haul cast. We are using the same fly rods and reels, only for this method we switch to 8WT fly rods.