Do Salmon Eggs Float? The Science Behind What Makes Them Sink or Float

Salmon eggs, also known as salmon roe are a popular bait for catching trout and other fish. But do salmon eggs actually float? It’s a common question many anglers have when preparing to use salmon eggs as bait. The short answer is that while salmon eggs can float temporarily, they will eventually sink due to their weight.

Why Might Salmon Eggs Appear to Float Initially?

When salmon eggs are newly deposited by the female salmon into the water, they may briefly float on the surface. This is because the eggs have an outer coating that makes them slightly buoyant when first released The coating helps protect the eggs as they transition from inside the salmon to the outside environment. However, this buoyancy only lasts for a very short time

Within minutes to hours of the eggs being deposited the outer coating wears off and the eggs will begin to sink. The eggs themselves don’t have any biological properties that make them float. Their temporary floating is solely due to the slimy protective coating when first released by the female.

What Causes Salmon Eggs to Sink?

Because they are so big and heavy, salmon eggs sink quickly once the shell breaks off.

Salmon eggs are large, averaging around 5 mm (0. 2 inches) in diameter. This makes them much heavier than water, so gravity pulls them downwards.

They also have a high density and are largely made up of proteins, fats, water, and minerals. This dense composition is heavier than freshwater, causing the eggs to sink rapidly.

Additionally, salmon lay their eggs in swift, highly oxygenated rivers and streams. The current moves the eggs downstream, where they are spread out at different depths as they sink. Within a few hours, most of them will settle in cracks and holes in rocks, which is the best place to protect and incubate the eggs.

Do All Salmon Species’ Eggs Sink?

While most salmon species lay eggs that sink, there is one exception. Pink salmon (also known as humpies) lay eggs that have an unusually buoyant outer membrane that allows them to float for several days after being laid. It’s thought this assists in dispersing the eggs further in the river system to reduce crowding.

However, even pink salmon eggs will eventually soak up water, rupture, and sink after floating for some time. No salmon species has evolved eggs that can float indefinitely.

Why Do Anglers Sometimes Use Floating Salmon Eggs?

While natural salmon eggs sink, there are some artificially made “floating salmon eggs” used for bait. Berkley Gulp makes a product called floating salmon eggs which are plastic beads made to mimic real roe.

The beads are infused with attractant and have a lower density than water, allowing them to float on the surface. They are made this way to match hatchery-raised trout’s experience with floating fish food pellets. The floating action can help entice trout to strike.

How Are Sinking Salmon Eggs Used For Fishing?

Since natural salmon eggs sink, most anglers use them as a bottom bait for trout. The eggs work well when drifted along the bottom in rivers or retrieved slowly along the bottom in lakes.

To get the eggs down deep, they are usually fished with some form of weight like a split shot or egg sinker ahead of the bait. The weight carries the eggs down quickly before they are swept downstream or disturbed by currents.

Anglers also try to match the small size, look, and scent of salmon eggs as closely as possible when selecting eggs for bait. Cheese-cured skein or jarred preserved eggs are popular choices as they hold up on the hook better than fresh raw eggs.

When fished properly, the drifting and tumbling action of sinking salmon eggs perfectly mimics the natural behavior of loose eggs rolling along the river bottom. This killer imitation makes salmon eggs one of the top producing baits for trout, steelhead, and salmon.

Tips for Fishing with Sinking Salmon Eggs

• Use a small hook (#10-14) to match the size of individual eggs.

• Add just enough weight to reach the bottom but still drift naturally in the current.

• Fluorescent colors like orange, chartreuse, and red help attract strikes.

• Keep the bait rig simple with a swivel, weight, leader, and hook.

• Target deeper pools, undercut banks, and drop-offs where trout wait in ambush.

• After a strike, wait a few seconds for the trout to fully engulf the egg before setting the hook.