Chinook Salmon Temperature and Depth: Why Kings Don't Always Follow the Temperature Chart

Search for Chinook salmon trolling advice and you will quickly find temperature charts.

One common starting point for Great Lakes kings is roughly 52 to 58°F. That range is useful, but it can become misleading if anglers treat it as a rule.

Wild Chinook do not spend every minute of the day inside one narrow temperature band.

They move.

And they can move a lot.

What is the preferred temperature for Chinook?

NYSDEC lists 52 to 58°F as a preferred range for Lake Ontario Chinook, with 53°F listed as an optimum. The same guide warns that trout and salmon regularly move outside their listed temperature ranges.

That warning matters more than many temperature charts make it appear.

A preferred-temperature number tells you where conditions may be favourable.

It does not tell you where every feeding Chinook will be.

Wild Chinook use a broader range

Lake Ontario tagging research compared Chinook salmon with lake trout and recorded detailed depth and temperature information.

Chinook occupied warmer and shallower summer habitat than lake trout and used a wider vertical and thermal niche.

The fish were not simply parked at one temperature.

They moved repeatedly through the water column.

Kings can move vertically at an impressive rate

The telemetry study estimated median cumulative summer vertical movement of about 103 metres per hour for Chinook.

Most lake trout in the same study averaged only about 7 metres per hour.

Again, that does not mean a king makes a 103-metre straight ascent every hour.

A fish might travel up 10 metres, down 15, up 20 and continue making repeated vertical movements. The total distance accumulates quickly.

For an angler, that behavior explains why a Chinook can appear far above or below the depth where a simple temperature chart says it "should" be.

Why would a Chinook leave ideal temperature?

The most obvious reason is food.

Alewife are a major prey item for Great Lakes Chinook.

Lake Ontario research found alewife vertical distribution was influenced by temperature and zooplankton density, and that many alewife moved upward around dusk as zooplankton moved toward the surface.

A predator capable of large vertical movements can take advantage of that.

The king does not have to choose between temperature and food permanently.

It can move between them.

Catch temperature changes through the season

Lake Ontario creel research also found that Chinook catch depth and temperature changed seasonally.

During spring, Chinook were relatively close to shore. Through May, June and July, they moved farther offshore and deeper. Later in the season, Chinook shifted toward shallower water and closer to shore as mature fish approached spawning tributaries.

That means a temperature number without seasonal context is incomplete.

A June feeding Chinook and a September staging Chinook are not behaving for exactly the same reasons.

Fish the marks, not the chart

Suppose your preferred-temperature target is 53°F at 65 feet.

Your sonar shows repeated large marks at 48 feet around bait.

Do not ignore those fish because they are sitting in warmer water.

Run something through them.

Now imagine the opposite situation.

The probe shows ideal temperature at 60 feet, but your sonar is empty while bait and predators are concentrated at 85 feet.

Again, fish the marks.

Temperature should narrow your search.

It should not override direct evidence.

How to build a Chinook spread around temperature

A useful starting spread should cover both the likely comfort zone and nearby feeding water.

If the main temperature break begins around 60 feet, do not put every presentation at exactly 60.

Cover above it.

Cover the break.

Cover below it.

Then watch what produces.

If several bites come 10 to 20 feet above your preferred temperature, move more lines there.

If the deep cold rods dominate, move the spread down.

Bait is often the deciding clue

One of the most useful combinations you can find is:

A defined temperature break.

A concentration of alewife.

Large predator marks nearby.

If those three overlap, the exact temperature number becomes less important.

Conversely, perfect temperature with no bait or predators may simply be empty comfortable water.

The practical rule for Chinook

Do not throw away the temperature chart.

Use it correctly.

A preferred temperature is a starting zone.

The actual fishing depth comes from the intersection of temperature, bait, season, fish marks and bites.

Kings are mobile enough to make rigid temperature rules unreliable.

That mobility is exactly why a wide initial trolling spread is so useful.

Sources

• NYSDEC temperature guidance.
• Raby et al., Chinook and lake trout telemetry research.
• Lake Ontario Chinook and rainbow trout seasonal catch-distribution research.
• Lake Ontario alewife vertical-distribution research.