top of page

Mind the Bighorn Redd

Updated: Mar 17, 2023

Being Mindful of the Currents We Wade.

As anglers of the Bighorn River, it is important to adopt action items that support the wild trout fishery, both individually and organizationally. One way anglers can act to benefit the fisheries is to adopt a Mind the Redd mindset. Mind the Redd is a spawning awareness movement created by guides in Colorado that encourages anglers to minimize negative impacts on wild fishes during critical spawning cycles. This means understanding the spawning times of trout, being able to identify vulnerable spawning grounds, and choosing to avoid wading on or casting to spawning trout. We ask anglers to be “mindful” of where they wade and fish by following the below steps.

Step 1. Know when Bighorn Trout Spawn.

The Bighorn River contains two species of wild trout: Brown trout that spawn in the fall, and Rainbow trout that spawn in the spring. While the exact spawning time of each individual trout varies within a 2-3 month window per season, it is important to understand that the eggs deposited remain vulnerable to disturbance until they can hatch, or become mobile. It is during this incubation period in which anglers should exercise caution when wading. Below are two hydrographs in which we have identified that period of time in which both rainbow trout eggs (top), and brown trout eggs (bottom) are in the gravels. As you can see, brown trout have a much longer incubation period than rainbow trout as cold fall/winter temperatures slow egg development.

Step 2. Learn to Identify Redds.

A redd is small oval depression or mound pattern in the gravel in which trout lay their eggs. Generally, these gravel nests are located in a foot or less of water, amid a steady flow of current. On the Bighorn, redds are usually congregated together in specific complexes along the river bank that will be cleaner and brighter than the surrounding riverbed (see below BHRA video).

Step 3: Avoid Wading Through Redds.

Each spawning trout deposits between 400 and 4000 pea sized eggs into a redd. On the Bighorn, BHRA has identified 11 major spawning complexes that can contain dozens of individual redds, and tens of thousands of trout eggs. Rainbow trout have eggs in gravels from mid May through mid July, while Brown trout have eggs in gravels for longer period, from mid October through May. Trout eggs are highly sensitive to disturbance and can easily be destroyed by being stepped on. It is recommended that anglers avoid wading through spawning grounds to ensure eggs (or newly hatched trout) remain undisturbed.

Step 4. Leave Spawning Fish Be.

While it is tempting to throw a cast to stacked up large trout in shallow water, it is recommended that you don’t. Spawning fish are at their most vulnerable during their spawn as they are exposed to would be predators, while simultaneously burning energy to make more fish. The females spend extra energy while working to build and protect the nests, while the males are burning calories battling one another for the chance to fertilize the eggs. These fish will often take a fly, lure, or bait simply to protect the nest or defend their right to the territory, not because they are feeding. Catching a fish that is actively spawning reduces the spawning success of that individual, while also increasing its mortality risk through excess energy consumption.

As we work on becoming "mindful" anglers, the BHRA is using drone footage to identify and monitor major spawning complexes on the river. Earlier this spring, BHRA's drone pilot Dennis Fischer surveyed 11 major Rainbow trout spawning complexes which may include up to 90% of active redds. Fischer will be collecting the same imagery this December during the peak of the Brown trout spawn. This imagery will help us monitor spawning habitat year to year, while also helping us advocate for sustainable flow releases that keep these important complexes viable.


Recent Posts

See All


bottom of page