Before taking the irreversible step of releasing hatchery fish into the ecosystem, fisheries managers have an ethical obligations to be completely sure than any such change is a good one.
Sunday, November 15, 2015
CAN HATCHERIES HARM SALT WATER FISH STOCKS?
Hatcheries have been a part of the freshwater fisheries scene for well over a century.
Initially seen as an unalloyed good that could reduce the impacts of overfishing and other adverse effects of an expanding population, hatchery fish have recently been subject to significant criticism. It has been argued that they degrade the fitness of wild-spawned fish, and that hatchery fish compete with wild fish for limited food and other resources.
The State of Montana stopped stocking trout in its rivers forty years ago, after studies indicated that eliminating hatchery fish will significantly increase a stream’s productivity.
On the other side of the Atlantic, the Scottish Fisheries Research Service, an agency of the Scottish Executive, warns that
“Stocking is only one of the tools available to fishery managers to restore or increase fishing opportunities. The decision as to whether or not to stock should not be taken in isolation, but as part of a broader plan for the management of the fishery as a whole. Such a plan should consider all the possible options. These include altering the level and distribution of fishing…
“Stocking can do harm as well as good, and ill-considered stocking exercises can have a deleterious effect on the wild resource…”
On the East Coast, hatcheries haven’t had too much of an impact on angling; their only significant and continuous use occurs in the Gulf of Mexico. Texas has what is, by far, the largest hatchery operation, which releases red drum and spotted seatrout
“to ensure that harvest levels are sustained and stocks are replenished…[and] to counterbalance the effects of habitat degradation, natural catastrophes and fishing pressure on the species.”
A paper written by an employee of the Texas Parks and Wildlife Department, about six years after the state’s red drum stocking program began, argued that the stocking effort was successful, noting that
“the number of fish harvested in bays that have been stocked has nearly doubled over historic mean harvest rates in those systems.”
However, it is important to note that “success” was gauged solely by an increase in angler harvest, not by more permanent values, such as an increase in the overall red drum spawning stock. In addition, there was no mention at all in the paper about any possible environmental downside caused by, for example, an adverse impact on the genetic makeup of the wild stock or stocked fingerlings competing with wild fish for food resources or nursery habitat.
Seen in that light, one comment in the paper can be read as a warning.
“The effectiveness of marine fisheries stock enhancement programs cannot be evaluated on an a priori basis. To measure the impact, fish must be stocked. Once they have been stocked successfully, the system will be forever changed. [emphasis added]”
That being the case, it might make sense to move forward very slowly when considering the release of hatchery fish into salt water environments.
The likelihood that marine fisheries managers may become more open to hatchery “enhancement” of coastal fish stocks is suggested in the National Marine Fisheries Service’s National Saltwater Recreational Fisheries Policy, which was released earlier this year. Once section of that policy, which was heavily influenced by various angling industry organizations, notes that
“Examples of strategies that NMFS supports include…[d]evelopment and application of aquaculture tools and technologies that support recreational fisheries.”
The phrase “aquaculture tools and technologies” sounds like a bureaucratic euphemism for “hatcheries,” and the fact that the same industry groups supporting this policy are the organizations trying to weaken the conservation and stock rebuilding provisions of current federal fisheries law provides plenty of reason for concern.
It’s not hard to envision such folks, already advocates for irresponsible fishery management, using the alleged success of the Texas hatchery program as a basis for arguing that it’s fine to overharvest wild marine fish stocks, so long as there is enough hatchery production “to assure that harvest levels are sustained.”
Freshwater fisheries management was led astray by just such Pied Pipers many decades ago, and is only now trying to undo some of the damage and restore healthy populations of native fish.
Even so, such an approach may already be moving forward in Mississippi, where the Mississippi Press-News reported that
“Marine biologists are trying to learn whether they can increase populations of [spotted seatrout and red snapper,] two of the Gulf of Mexico’s most popular sport and food fish—and perhaps further relax quotas on one of them—by raising and releasing small fry. [emphasis added]
Not everyone is sold on the idea. The Press-News quoted Alec D. MacCall, a senior scientist at NMFS’ fisheries ecology division based in Santa Cruz, California, who observed that
“The real fundamental problem is fisheries reform. If a hatchery effectively stops management reform for the natural stock, I’d be hesitant to call anything successful.”
The industry folks who would use hatchery production to justify overfishing would, of course, disagree.
Earlier this year, two biologists, Gregory T. Ruggerone and Brendan M. Connors, published a paper entitled “Productivity and life history of sockeye salmon in relation to competition with pink and sockeye salmon in the North Pacific Ocean.“ It described the sort of problems that hatchery fish might cause when large numbers of them are introduced into a marine ecosystem.
Ruggerone and Connors began by investigating why sockeye salmon runs were declining sharply over a wide area that extended from southern Alaska down the entire coast of British Columbia and into the rivers of Washington. Anything that could affect sockeye salmon over such a broad geographic area, and spanned fish returning to so many river systems, had to be taking place out at sea.
Eventually, they found a strong correlation between declines in sockeye salmon and increases in the numbers of pink salmon. More specifically, they found that the growth, age at maturity and survival of sockeye salmon were adversely impacted when the sockeye had to compete for food with large numbers of pink salmon during the sockeyes’ second year in the sea.
That becomes relevant to the hatchery debate because, in recent years, hatcheries in both Alaska and Russia have been ramping up salmon production, and pink salmon have comprised a large part of the approximately 5 billion salmon that are released into the ecosystem every year. To minimize the impact on sockeye salmon, the paper’s authors recommend that hatchery production be capped.
Not surprisingly, the folks who run the hatcheries don’t accept the researchers’ finding and recommendations.
Some challenge the science, arguing that there is no link between the seeming correlation and actual causation.
Others take a more fatalistic view, suggesting that the harm was inevitable. Along with challenging the science, Steve Reifenstuhl, the general manager of Northern Southeast Regional Aquaculture reportedly responded to the paper by saying
“Do you think that we can control Russia? Russian [sic] and Japan would quickly move to fill that void if there were a cap.”
What Reifenstuhl left unsaid was exactly what he meant by “void” and why he believed that both Japan and Russia wouldn’t maximize hatchery production regardless of anything that Canada and the United States might do.
Others emphasized economics. Trent Dodson, production and operations manager for the Kodiak Regional Aquaculture Association, said that
“when we had a low wild pink salmon return and a better than average hatchery return, we were able to help bridge that gap and provide a [sic] economic benefit for common property fishermen that wouldn’t have been there otherwise.”
Thus, hatchery supporters repeat a common theme whether they are dealing with the recreational red drum fishery in Texas, the mixed red snapper fishery in Mississippi or the commercial salmon fishery in Alaska: Hatcheries let people kill more fish.
They also seem joined by another common theme: None of them appear to be giving serious consideration to the damage that hatchery fish may do out in the ocean, when they compete with wild-spawned fish of their own or perhaps of other species.
Given Ruggerone and Connors’ work, fisheries managers shouldn’t be so unconcerned about the effects of releasing hatchery fish into our marine waters.
As the Texas Parks and Wildlife biologist has already told us,
“Once they have been stocked successfully, the system will be forever changed.”