New Book on Global Amphibian Declines

Jim Collins and Martha Crump recently published a new book entitled, "Extinction in Our Times: Global Amphibian Decline". This is a complex subject and by all accounts the authors do a great job of synthesizing this material for the scientifically-inclined as well as for more general audiences. Joe Mendelson, a scientist at the Atlanta Zoo and one of the key players in the Amphibian Ark project, posted this review on book's Amazon web page

The authors have accomplished something spectacular here. They have taken a very disturbing and complex story---that has its share of intertwined controversies, to be sure---and assembled a remarkably objective and even-handed summary. The book doesn't foolishly proclaim to have solved all the mysteries, nor offer a silver-bullet panacea for the amphibian crisis. Rather it presents a fully readable retrospective and current review of the crisis of amphibian declines and extinctions and an interesting perspective on how science as a process, and the scientists as people, responded to an unprecedented set of circumstances. The authors do an especially good job at maintaining full objectivity in the face of ongoing controversies and disagreements among scientists. Similarly, to treat fairly the scientists and hypotheses that time has shown to have been "wrong"---or, better said, the ideas and conclusions that are not supported by all of the accumulated data. The nice style adopted by the authors throughout the book is to simply point out which hypotheses are the best supported by the data. There are no "winners" or "losers" among the people and ideas presented in this book, as the authors imply that all contributions to the amphibian crisis have been important.

We have a long way to go in understanding and confronting the ecological catastrophe of global amphibian declines and extinctions. But this book is a complete summary of where we've been and where we are positioned today in this phenomenon. Importantly, the authors also pay especial attention to how we got to our current position of knowledge and conservation action. This aspect of the book makes for a fascinating study of how a completely unorganized cohort of scientists responded when the found themselves suddenly in the face of an overwhelming conservation challenge. In retrospect, the scientists responded quite slowly. But after reading this book, you will realize that no other response was possible.

I hope this book is read carefully by scientists, conservationists, and policymakers working on other aspects of the global environmental crisis. This case study of the amphibian crisis offers many lessons applicable to other biodiversity crises, be it fungal infections in bats or die-offs of coral reefs. The book also offers a complete overview of the phenomenon of amphibian extinctions. I wish all reporters and science writers covering the subject would give this a careful read before beginning their stories! Kudos to the authors for a remarkable and easily absorbable synthesis of a very complex story.

So, if you want to learn the latest about one of the most profound extinction events in recorded history, this book should fit the bill.

Back to The Mountain Yellow-legged Frog Site.

Fish Stocking EIR/EIS - Part 5

Anybody who read the California Department of Fish and Game (CDFG) draft fish stocking EIR-EIS knows that this document is badly flawed. Many of these flaws, such as an inadequate range of alternatives, are fundamental to the entire document and addressing them would require a major rewrite of the EIR-EIS. However, the court-ordered deadline for the final EIR-EIS is January 11, 2010. How is the CDFG going to make all the necessary changes to this document in time to meet this deadline?

One possibility would be that the CDFG could go back to the Court and request a deadline extension. However, the CDFG is apparently determined to meet the original January 11 deadline, so I'm guessing that instead we will see a final EIR-EIS that is only marginally improved from the draft version. That will undoubtedly result in another lawsuit, and given that the same CDFG legal counsel who lost the previous fish stocking lawsuit will be providing advice again this time around, the CDFG will lose again and will be forced to make the necessary major revisions to the EIR-EIS that many people have been calling for all along.

The inadequacy of the current draft EIR-EIS and all the shenanigans that are likely to follow could have been avoided if the CDFG had decided from the very beginning of this process to thoroughly and honestly evaluate the environmental costs and benefits of their fish stocking program. Instead the CDFG did what they usually do on this issue, which was to first decide what the document's conclusion would be (i.e., continue the current fish stocking program), and then use every imaginable argument to justify this conclusion, no matter how ridiculous these arguments are. When this process has finally run its course, I suspect that the CDFG would have spent much less money, done a better job of protecting native species, and produced better recreational fisheries if they had used the CEQA process the way it was intended.

And this from an agency whose stated mission is "to manage California's diverse fish, wildlife, and plant resources, and the habitats upon which they depend, for their ecological values and for their use and enjoyment by the public". If only the CDFG would take their stated mission seriously....

Back to The Mountain Yellow-legged Frog Site.

Fish Stocking EIR/EIS - Part 4

The DFG trout stocking program currently introduces millions of fingerling, sub-catchable, and catchable trout into lakes and streams throughout California with the goal of improving existing fisheries. In addition to stocked trout, recipient habitats typically also harbor native trout populations or established non-native populations, with the latter having become established following earlier stocking efforts (both are referred to here as “resident” populations). In light of the fact that numerous studies have indicated that trout stocking has the potential to impact these resident trout populations and thereby negatively affect fishery quality it is ironic that the EIR-EIS fails to analyze stocking impacts on recreational trout fisheries.

The court order required the DFG to analyze the environmental impacts of the current stocking program and it is difficult to conceive of such an analysis not including an assessment of impacts of stocking on resident trout fisheries. In the EIR-EIS, this analysis is restricted solely to the effects of trout stocking on a few special-status native trout species (e.g., golden trout). Such a narrow interpretation of "environmental impacts" is unacceptable. As the following discussion makes clear, the potential exists for the current trout stocking program to seriously impact resident trout populations and adversely affect recreational fishing opportunities. These impacts should be analyzed and disclosed.

In an overview paragraph describing the effects of stocked trout on other salmonids the EIR-EIS (page 4-66) states,

“Most hatchery rainbow trout that are stocked for put-and-take fisheries in streams are caught within 2 weeks of planting (Butler and Borgeson 1965; Moyle 2002), and the remainder likely die of starvation or stress within a few weeks (Moyle 2002). Therefore, the potential for impacts on native trout species through competition and predation associated with catchable-sized rainbow trout plantings in streams appears to be low.... Catchable-sized hatchery rainbow trout released into lakes survive for longer periods than stream stocked fish because of lower energy costs associated with the absence of stream currents, and a relatively lower vulnerability to angling and predation (Moyle 2002). Therefore, the duration of competitive and predatory impacts on native lake populations following stocking of catchable-sized trout should be greater than the impacts following stream stocking.”

A less selective presentation of the available scientific literature would clearly indicate that the introduction of hatchery trout can negatively impact resident trout in both streams and lakes. In streams, direct effects are well-documented and usually result from competition between stocked and resident trout. This competition can produce slower growth rates (Weiss and Schmutz 1999, Bohlin et al. 2002), increased movement (Vincent 1987), and increased mortality of resident trout (Petrosky and Bjornn 1988, Baer and Brinker 2008). In addition, stocking catchable trout can increase fishing effort and in turn increase capture and removal rates of resident trout (Baer et al. 2007). These effects can subsequently result in lower overall trout densities (Vincent 1987).

The study by Vincent (1987) provides a particularly detailed description of the consequences of stocking hatchery trout into rivers and streams that contain resident trout populations. In this study, the long-term stocking of hatchery trout into the heavily-fished Varney section of the Madison River was halted and concurrently an unstocked tributary (O’Dell Creek) began receiving plants of hatchery trout. After four years of no stocking in the Varley section, the number and biomass of 2-year-old and older resident brown trout increased by 160%. Resident rainbow trout numbers increased by 800% and biomass increased by 1000%. In contrast, three consecutive years of hatchery trout stocking into O’Dell Creek resulted in a 49% reduction in the numbers and biomass of 2-year-old and older resident brown trout. The obvious conclusion from this study is that the stocking of hatchery trout can have dramatic impacts on resident trout populations and can in some cases actually decrease the quality of trout fisheries. As a result of the Vincent (1987) study, the State of Montana eliminated all stocking of flowing waters and restricted stocking only to lakes and reservoirs.

Impacts from stocking trout into lakes that contain resident trout are more poorly understood than impacts in flowing waters. However, two studies provide important insights. Elser et al. (1995) studied the consequences of halting rainbow trout stocking in Castle Lake, a historically fishless lake in northern California that at the time of the experiment contained introduced rainbow trout and brook trout. The brook trout population was capable of natural reproduction in Castle Lake but the rainbow trout population was maintained entirely by stocking. When rainbow trout stocking was halted, brook trout recruitment increased. Three years after rainbow trout stocking was halted, total trout numbers had increased by 20% (previous dominance by rainbow trout now replaced with dominance by brook trout) and total trout biomass had increased by 30%. In the Sierra Nevada,  Armstrong and Knapp (2004) compared trout densities and growth rates in 61 alpine lakes before and after a 4-8 year period of no fish stocking ("stocking-termination" lakes), and also between the stocking-termination lakes and control lakes that continued to be stocked. Contrary to the expectation that Oncorhynchus species stocked into alpine lakes rarely establish reproducing populations, results indicated that 70% of the stocking-termination lakes actually contained reproducing trout populations. For these reproducing populations, 4-8 years of no stocking resulted in no detectable change in trout density and may have resulted in increased trout growth rates in some lakes. Therefore, as in flowing waters the stocking of hatchery trout into lakes can actually reduce total trout numbers and biomass, with negative consequences for fishery quality.

In summary, the results from these and many other studies lead one to the unavoidable conclusion that in at least some situations no stocking will actually result in better fisheries than intensive (and expensive) fish stocking. Given the potential severity of fish stocking impacts on resident trout populations and trout fisheries (and the associated costs), it is clear that the EIR-EIS must provide a thorough analysis of these impacts. 


References
Armstrong, T. W. and R. A. Knapp. 2004. Response by trout populations in alpine lakes to an experimental halt to stocking. Canadian Journal of Fisheries and Aquatic Sciences 61:2025–2037.

Baer, J., K. Blasel, and M. Diekmann. 2007. Benefits of repeated stocking with adult, hatchery-reared brown trout, Salmo trutta, to recreational fisheries? Fisheries Management and Ecology 14:51-60.

Baer, J. and A. Brinker. 2008. Are growth and recapture of hatchery-reared and resident brown trout (Salmo trutta L.) density dependent after stocking? Ecology of Freshwater Fish 17:455-464.

Bohlin, T., J. I. Johnsson, and J. Pettersson. 2002. Density-dependent growth in brown trout: effects of introducing wild and hatchery fish. Journal of Animal Ecology 71:683-692.

Elser, J. J., C. Luecke, M. T. Brett, and C. R. Goldman. 1995. Effects of food web compensation after manipulation of rainbow trout in an oligotrophic lake. Ecology 76:52-69.

Petrosky, C. E. and T. C. Bjornn. 1988. Response of wild rainbow (Salmo gairdneri) and cutthroat trout (S. clarki) to stocked rainbow trout in fertile and infertile streams. Canadian Journal of Fisheries and Aquatic Sciences 45:2087-2105.

Vincent, E. R. 1987. Effects of stocking catchable-size hatchery rainbow trout on two wild trout species in the Madison River and O'Dell Creek, Montana. North American Journal of Fisheries Management 7:91-105.

Weiss, S. and S. Schmutz. 1999. Response of resident brown trout, Salmo trutta L., and rainbow trout, Oncorhynchus mykiss (Walbaum), to the stocking of hatchery-reared brown trout. Fisheries Management and Ecology 6:365-375.


Back to The Mountain Yellow-legged Frog Site.

Fish Stocking EIR/EIS - Part 3

In this post I'll focus on one of the most serious shortcomings of the EIR-EIS: the method used to evaluate the impacts of the current stocking program. In most CEQA documents the environmental impact of a new project is judged by comparing environmental conditions expected under the new project against the current environmental conditions (i.e., without the project). Applying this approach to the current CEQA fish stocking analysis would suggest that impacts of the current fish stocking program would be judged relative to those under a "no stocking" alternative. Paradoxically, the EIR-EIS assesses impacts by comparing those caused by fish stocking in the period 2004-2008 (the "baseline") against impacts caused by previous stocking. As stated on page 1-3,

"DFG’s intent in this EIR/EIS is to analyze the environmental effects of a number of specific programs it currently manages that surround the rearing and stocking of a specific set of fish species. The whole of these individual programs is referred to as “the Program” in subsequent chapters, and serves as the baseline and No Action alternative as defined by CEQA. The detailed analysis of the current condition or baseline, as contained in Chapters 3–6, is not typical for CEQA or NEPA, which usually analyze a proposed project or proposed action. However, the court order that directed preparation of this EIR/EIS mandated that DFG analyze its current fish stocking program."

Under this analysis approach, as long as the impacts that occurred during the 2004-2008 baseline were similar in magnitude to those that occurred during previous stocking the impact of the current stocking would be deemed "non-significant". This conclusion regarding impact significance would be unchanged even if the impacts of the 2004-2008 stocking and previous stocking were both severe.

That this twisted logic produces scientifically unsupportable assessments of impact is hardly surprising. One example relates to the assessment of trout stocking impacts on the long-toed salamander (Ambystoma macrodactylum). In California, this species was historically widely distributed in the Sierra Nevada, Klamath Mountains, and Cascade Mountains where it inhabited a wide variety of perennial fishless ponds and lakes. Several recent studies have reported that A. macrodactylum is typically eliminated from these habitats following trout introductions and this species is clearly much less common in California today than it was historically. Similarly severe impacts of stocked trout on A. macrodactylum have been reported from elsewhere in the western U.S. Despite these well-documented impacts of stocked trout, the EIR-EIS concludes the following (page 4-76):

"Although historic trout stocking likely resulted in a geographically widespread extirpation of long-toed salamander populations from high mountain lakes in the Sierra Nevada, Cascade and Klamath mountain ranges, the continuing conduct of the trout-stocking program during the 2004-2008 baseline period has likely not resulted in any further population changes that would constitute a significant impact on the long-toed salamander. Thus the impact of the trout stocking program is less than significant."

In light of well-established impacts of stocked trout on A. macrodactylum, this finding of non-significance is untenable. Unfortunately, the EIR-EIS is replete with many other scientifically indefensible conclusions that are a consequence of the flawed methods used in these impact analyses. The only way to thoroughly analyze the impacts caused by the current stocking program is to compare those impacts against the impacts that would occur with no stocking.

In my next post I'll focus on the failure of the EIR-EIS to analyze the impacts of the current stocking program on resident trout fisheries. To give people time to read this post before comments to the DFG are due (November 16), I'll move my next post up from November 16 to the middle of this week.

Back to The Mountain Yellow-legged Frog Site.

Fish Stocking EIR/EIS - Part 2

Last week I mentioned that in my next post I'd write about the flawed evaluation of fish stocking impacts in the California Department of Fish and Game (CDFG) draft EIR/EIS. So, here goes. The flawed evaluation derives from two sources: (1) an inadequate range of management alternatives considered, and (2) the use of the last five years of fish stocking as a baseline against which to judge impacts. I'll focus on #1 this week and on #2 next week.

The draft EIR/EIS analyzes three alternatives. These are (1) no project/no action, under which no changes would be made to hatchery operations and stocking programs; (2) continue to operate hatcheries as in the past five years and stock fish based on new guidelines - this is the "preferred alternative"; and (3) permanently operate the hatchery and stocking program as directed in the interim court order, under which no stocking would occur where any of 25 sensitive native species occur or where surveys for these species have not been conducted. Given that the "new guidelines" proposed in the EIR/EIS for the preferred alternative (#2 above) are minor mitigation measures at best, these three alternatives represent an unnecessarily narrow range of alternatives and none would result in a substantive change in the current fish stocking program. This failure to analyze a broader range of alternatives is very unfortunate because it means that the CDFG is missing a chance to change its fish stocking program in ways that would benefit native species AND recreational fisheries. An alternative that seems an obvious one to have been included in the analysis is one that proposes halting stocking in flowing waters and refocusing the stocking program on less sensitive habitats such as artificial impoundments. No such luck.

On page 7-6 of the EIR/EIS it is mentioned that the termination of stocking in flowing waters was considered as an alternative but it was eliminated from further analysis. The rationale for its elimination was as follows: "The alternative was suggested as patterned after a similar practice followed by the State of Montana regarding its stocking guidelines. Demand for recreational fishing in flowing waters is far greater in California than in Montana. Eliminating stocking altogether in flowing waters would place considerable pressure on native and wild stocks that already exist in flowing waters and would eliminate a large proportion of the recreational fishing opportunities for anglers that wish to camp and fish along waters in California." This rationale is absurd.

The state of Montana stopped stocking all flowing waters based on studies that showed that this stocking was having such serious impacts on resident trout that the net result of stocking flowing waters was a dramatic reduction in trout numbers. The termination of stocking resulted in similarly dramatic increases in the number of trout present. These studies (summarized here) were conducted, in part, on the Madison River which is one of the most heavily fished rivers in Montana. So, for the CDFG to argue that they have to continue stocking flowing waters because of high angler pressure makes absolutely no sense when stocking could in fact be harming these fisheries. Once again the CDFGs working assumption is that stocking is the only solution to improving angling opportunities. At the very least, the CDFG should have included an alternative that proposed eliminating stocking in flowing waters and analyzed the alternative in detail.

Some might reasonably wonder why a "no stocking" alternative was not included in the EIR/EIS. For the trout stocking program, the reason appears to be that the CDFG is mandated by recent legislation (AB 7, passed in 2005) to stock a certain number of trout per fishing license sold. In 2009 and subsequent years, the CDFG is required to stock a minimum of 2.75 pounds of trout per fishing license sold in 2008, 2.0 pounds of which must be of catchable size or larger. The portion of the California Fish and Game Code that summarizes these requirements is available here. The fact that this legislation dramatically constrains the range of alternatives that the EIR/EIS could consider is very unfortunate. But there os a deeper irony here. Legislators tried for several years to pass AB 7 and were always stymied by California Trout ("CalTrout"), a fishing organization that opposed the legislation. CalTrout finally threw its support behind the bill after getting language inserted into the draft legislation that allocated two million dollars to CDFGs chronically underfunded Heritage and Wild Trout program. With CalTrout now supporting the legislation, AB 7 was signed into law. Now a few years later, AB 7 is precluding the EIR/EIS from considering reductions in the number of trout stocked annually, reductions that could actually improve fisheries. I hope the directors of CalTrout are fully aware of the consequences of their support for this screwy legislation.

More next week....

Back to The Mountain Yellow-legged Frog Site.

Fish Stocking EIR/EIS - Part 1

As stated in last week's blog post, the California Department of Fish and Game (CDFG) recently released their draft fish stocking EIR/EIS to the public. Comments are due on November 16. When the CDFG was ordered by the court to conduct this environmental analysis I had some hope that the CDFG would use this as an opportunity to fully evaluate their current stocking program and make changes that would benefit native wildlife (e.g., native amphibians and fish) and improve fisheries. Unfortunately, a read of the document's objectives statement indicates that this environmental analysis was largely an effort to justify the current fish stocking program. The objectives statement (page 5) reads, "The fundamental objectives of DFG’s Program are to continue the rearing and stocking of fish from its existing hatchery facilities for the recreational use of anglers, for mitigation of habitat loss attributable to dam construction and blocked access to upstream spawning areas, for mitigation of fish losses caused by operation of the state‐operated Sacramento–San Joaquin River Delta pumps, and for conservation and species restoration."

This objectives statement ignores abundant evidence that the stocking of trout and salmon can actually have negative effects on the resident fishery. For example, stocking of "catchable" trout into streams results in high levels of competition between stocked and resident trout. The end result is often a reduction in the total number of trout present. Similar problems beset stocking of salmon species. Given an abundance of these sorts of findings it is not at all clear that fish stocking is always the preferred means of providing recreational angling opportunities or that stocking can in fact mitigate for habitat loss caused by dams. As such the objectives statement in the EIR/EIS indicates the CDFGs interest in continuing the current stocking program regardless of whether some aspects of that program actually have negative effects on fisheries.

I would have liked to see an objectives statement such as the following: "To provide a stocking program that supports diverse anadromous and inland salmonid fisheries and protects native species and natural resources from adverse impacts from stocking." This statement makes it clear that fish stocking is a management tool that would be used when necessary to improve fisheries. I proposed this objectives statement to the CDFG some months ago but obviously my suggestion fell on deaf ears.

Given the flawed objectives statement upon which the EIR/EIS is based it is little surprise that the environmental analysis supports the continued fish stocking program with few meaningful changes. Next week I'll discuss the CDFGs flawed evaluation of fish stocking impacts.

Back to The Mountain Yellow-legged Frog Site.

Another Field Season has Come and Gone

My 2009 summer field season ended in late September. Now weeks later all of the research gear is put away and the data is safely in my lakes database. The summer went largely as expected, with some notable successes and some unanticipated challenges. Below I've provided a summary of what our summer objectives were and what we actually accomplished. But first a sad note....

This summer I lost a close friend and fellow field biologist. On August 30, Jeff Maurer died in a climbing accident while ascending Third Pillar on Mt. Dana. Jeff had worked in Yosemite National Park since 1988, studying Peregrine Falcons, Great Gray Owls, and Northern Goshawks. In 2006 he took on the task of leading Yosemite's new lake restoration program, and in that capacity he directed fish removal efforts in numerous key locations around the Park. These efforts will continue, of course, but Jeff's infectious enthusiasm and unmatched dedication to this restoration effort will be sorely missed. He was truly one-of-a-kind. For stories about Jeff, check out http://yosemite-jeffmaurer.blogspot.com/.

So, what did we set out to do this summer? Our research team (me, Cherie Briggs, Vance Vredenburg, Erica Rosenblum, and more than a dozen field and laboratory assistants) had two primary objectives. The first objective follows from our field observations that after the arrival of the amphibian chytrid fungus (Batrachochytrium dendrobatidis - "Bd") at a site most mountain yellow-legged frog populations decline to extinction but a few persist despite the disease, albeit at markedly lower densities. There are several potential explanations for these different disease outcomes, including inherent differences in frog susceptibility to chytridiomycosis (the disease caused by Bd) or differences between Bd strains in their virulence. So this summer we conducted a laboratory experiment to evaluate the relative roles of these two factors in driving different disease outcomes (frog population persistence versus extinction). We hope to wrap up the experiment by December.

Our second objective was to use a field experiment in which mountain yellow-legged frogs are cleared of Bd to determine whether this treatment influences the outcome of Bd epidemics. Frogs were treated with an anti-fungal drug at three lakes in each of two basins located in Kings Canyon National Park. Frog populations in both basins had suffered catastrophic declines in the past four years following the arrival of Bd, and without intervention it is likely that these frog populations would have been extinct within another couple of years. It will be 1-2 years before we have any definitive results but for now, suffice it to say that we were able to significantly reduce Bd loads on frogs in the field and this treatment dramatically improved frog survival. I'm hopeful that such frog treatments may provide us with an important conservation tool in the future, but we still have lots of unanswered questions that need to be addressed. I'll provide further updates as the results come in.

Finally, the California Dept. of Fish and Game (CDFG) released a draft fish stocking EIR/EIS to the public on September 25 (available from the CDFG web site). Comments on the draft document are due to the CDFG by November 16. Given that this document will guide CDFG fish stocking practices for many years I encourage everyone interested in this issue to read the EIR/EIS and provide comments to the CDFG. I'm still working my way through the 8 chapters and 12 appendices but it is clear that there is lots of room for improvement. I'll provide additional details on this document in upcoming blog posts. Stay tuned....

Now that I'm back behind my desk I'll be posting new Frog Blog entries every Monday morning. I hope you find them interesting and informative.

Back to The Mountain Yellow-legged Frog Site.