Tom Remington recently wrote a blog entry on sterile fish and their potential to grow faster and perform better than fertile hatchery fish, which allocate a portion of their growth potential toward reproduction.  The topic is a very interesting one, especially since sterile hatchery fish do not threaten wild populations with the potential for interbreeding and compromising genetic integrity.

Many state fish and wildlife agencies will tell you that they do not stock fish with the intent of seeing them reproduce.  The vast majority of stocking programs are either put-and-take, or put-grow-and-take, where fish are stocked with the intention of becoming part of an angler’s bag limit.  Furthermore, most waters are stocked because they cannot provide a fishery through natural reproduction.  Most agencies use regulations as a first resort to protect a fishery.  If natural reproduction simply can not keep up with angling pressure regardless of regulations, a stocking program is usually implemented.  This lack in natural reproduction is often due to lack of spawning habitat, but can result from other causes as well.

The bottom line is this: if most fish are stocked without the intent of reproducing, what drawbacks are there to a sterile fish that has the potential to grow faster?  I don’t see many.  Convincing the public that it’s a good idea to stock sterile fish might be a tough sell, simply because most people still don’t quite understand why a department would stock fish without expecting them to reproduce.

One of the greatest benefits to a stocking sterile fish, in my opinion, is the ability to stock these fish in waters that contain native fish that might otherwise be threatened with interbreeding or hybridization.  This means that states can stock wild trout waters with hatchery trout, knowing that they are not compromising the genetics of wild fish. 

Granted, you can’t just go willy nilly stocking on top of native fish everywhere you go.  There are issues in some areas where hatchery fish could potentially outcompete wild fish.  There are some areas where stocking is not necessary and might hinder a wild fishery in recovery.  Also, the method of sterilization, while significantly developed in some areas, is not yet foolproof.

The Idaho Department of Fish and Game has been working on producing sterile triploid hatchery fish for years, and to date, every rainbow trout stocked in the state of Idaho is sterile.  Therefore, the department has the freedom to stock in areas where they might otherwise have to worry about hatchery rainbows interbreeding with wild rainbows and hybridizing cutthroat trout populations. 

Sterilization of hatchery fish is an advancement led by state fish and wildlife agencies primarily in the West.  Idaho Fish and Game fisheries biologist Joe Kozfkay and others completed a survey of state fish and wildlife agencies throughout the U.S., and found that 10 other states have current sterilization programs, and most are in the West.  Only 2 states with fish sterilization programs lie east of the Mississippi River.

While there are some hurdles to overcome, primarily the logistics of developing a sterilization program and having state agency and public support, I believe that the future is promising and many developments lie ahead.  Because of the ever-increasing concern over the protection of native and wild fish, it is imperative that state agencies at least consider the development of a sterilization program.  Aside from it likely being mandated in the future, such a program would vastly increase the options that state fish and wildlife agencies have in relation to where they stock fish.