December 31, 2008

Editorial About Court-ordered Fish Stocking Suspension

Today's San Francisco Chronicle contains an editorial (page B-7) on the recent court ruling that suspended fish stocking in some California water bodies in 2009 (for background see my 11/21/08 Frog Blog post). I wrote this piece as a counterbalance to the many stories on this topic printed recently in newspapers that decried the stocking suspension as having major negative consequences for local economies and fisheries. My prediction? Neither will be true.

Back to The Mountain Yellow-legged Frog Site.

December 29, 2008

The Angling Community's Dark Side

For thirty years I was passionate about fly fishing and carried a fly rod and a box of hand-tied flies wherever I went in wild places throughout California and the West. As a kid, fishing connected me to aquatic habitats and led me on a life-long pursuit of an endless list of ecological questions: Why did some lakes harbor a few large fish and others many small fish? What species of mayfly was that hatching in June in low elevation lakes in Yosemite? Why did I rarely find mountain yellow-legged frogs co-occuring with introduced trout in Sierran lakes? What invertebrates used to occur in these lakes before trout introductions? My enthusiasm for fly fishing was eventually tempered by the results of my own research that showed how dramatically fish introductions had altered the lakes and streams of the Sierra Nevada. After the passage of Assembly Bill 7 in 2005, the bill that required that a larger portion of fishing license dollars be spent raising hatchery trout, I finally gave up fly fishing entirely, no longer able to justify buying a fishing license and in doing so directly supporting the California Department of Fish and Game's (CDFG) stocking practices.

Today I often find myself at odds with the majority of California's angling community, a majority that often rails loudly at any efforts to modernize the CDFG stocking program and protests any proposal to restore native amphibians by removing selected nonnative trout populations. The majority's most vocal spokesmen (yes, they are all men) use newspapers as their bully pulpit to stir their angling readers into a froth over a wide range of angling issues, including the recent stocking moratorium in some California waters (see my December 1, 2008 post for an example). In doing so, they have repeatedly failed to recognize changing public sentiment that increasingly favors protection for endangered species and wild lands, and have refused to acknowledge that fish introductions have resulted in widespread impacts to aquatic ecosystems. This "head in the sand" approach is leading to an ever-increasing reliance on put-and-take stocking programs and to the view that California's lakes, streams, and rivers are little more than glorified hatchery raceways where we can dump thousands of hatchery-reared trout without negative consequences to the resident trout and to the native vertebrate and invertebrate fauna.

During all of this debate and rhetoric, a commonly-voiced sentiment is one that has anglers as the "original environmentalists", caring deeply for the habitats that sustain their quarry. Perhaps that is true, but I sure don't see much evidence of it these days. In fishing-related chat rooms (e.g., High Sierra Topix) it is common to find posts claiming that introduced trout have no negative impacts on native biodiversity, that the claim of fish effects on mountain yellow-legged frogs is a hoax perpetrated by wacko scientists (like yours truly), and urging anglers to take fish stocking into their own hands and move fish into the few lakes that remain
fishless. Such rhetoric will do nothing to improve California's fisheries.

In our haste to catch fish, it seems that we've forgotten that the quality of fishing is intimately connected to the health of the ecosystem. The decline of mountain yellow-legged frogs shouldn't be seen as a threat to fishing but as an indicator that all is not well in aquatic habitats of the Sierra Nevada. Should we care that trout introductions have impacted a large number of native taxa, from Callibaetis mayflies to mountain garter snakes to Gray-crowned Rosy Finches? I think so, because even from the most angler-centric view declines in these species indicate the loss of important trout prey. If we claim to love the Sierra Nevada so much, how can we not care about these impacts?

California's angling community could be a powerful agent for change - for healthy habitats and better fisheries - if it could shelve the rhetoric and roll up their collective sleeves to do the hard work of coming up with a plan to manage California's fisheries, wildlife, and habitats for a sustainable future.

Back to The Mountain Yellow-legged Frog Site.

December 12, 2008

Frog Restoration - the State of the Science

Numerous mountain yellow-legged frog recovery projects have been conducted in the last five years, with more in the planning stages. Virtually all of these projects relied on the removal of nonnative trout and most have met with stunning success. As a result of this work, there is now an abundance of information available on the details of how to remove nonnative trout. But how do we go about selecting sites for restoration? What makes the ideal restoration location?

The mountain yellow-legged frog restoration projects conducted to date have had as their goal increasing the amount of fishless habitat available to an existing frog population. These target frog populations are often small and relegated by the presence of trout to marginal habitats (e.g., shallow ponds). In these projects, site selection was straightforward: choose sites that (1) are in close proximity to existing frog populations, (2) contain high quality frog habitat, and (3) have the appropriate characteristics to allow fish population removal using mechanical means (gill netting, electrofishing). Criterion 1 ensures that mountain yellow-legged frogs will be able to recolonize the restoration site following fish removal. For Criterion 2, high quality habitat is generally characterized as lakes deeper than 3 m (10'), located at elevations below 3600 m (11800'), and surrounded by other suitable habitats including fishless lakes, ponds, marshes, and low-gradient streams (see Knapp et al. 2003 for details). Criterion 3 requires that there are no upstream fish populations and that fish from downstream locations are prevented from moving into the site by natural barriers on the interconnecting streams. In addition,
the chance of successful fish removal is increased by limiting lakes to those of small to moderate size (<20 style="font-style: italic;">Batrachochytrium dendrobatidis - "Bd") into the Sierra Nevada has the potential to considerably complicate restoration site selection. Most restoration projects conducted so far have been in areas in which Bd has not yet arrived. In areas where Bd is present, additional site selection criteria will likely be necessary to maximize the chances of successful frog restoration. In particular, we need to understand the conditions that limit Bd and thereby allow the growth and persistence of frog populations. Bd grows best at water temperatures of approximately 20 degrees C (70 F) and ceases growth above 30 C and below 4 C. In landscapes in which Bd is now ubiquitous (e.g., Yosemite National Park) we are currently studying how temperature regimes affect disease outcomes in frog populations. For example, do temperature effects on Bd growth rates result in increased frog survival in high elevation (i.e., cold) habitats compared to those at low elevations? Is frog survival increased when frogs have access to warm-water habitats such as marshes in which temperatures often exceed 25 C? Answers to such pressing questions are critically needed and we are working feverishly on these studies. Given the ongoing spread of Bd across the Sierra Nevada, the information provided by this research should help guide the selection of sites for future frog restoration projects.

Despite the typical focus of fish removal projects on the mountain yellow-legged frog, we can't lose sight of the fact that trout removal benefits not just frogs but a diverse community of vertebrate and invertebrate taxa. I maintain that having at least some fishless lakes and streams in each watershed across the Sierra Nevada is the most foolproof way to ensure the persistence of these native taxa. Sometimes that will mean removing trout from a lake even if frog recovery is unlikely.

Back to The Mountain Yellow-legged Frog Site.

December 1, 2008

DFG Releases List of 2009 Stocking Locations

In response to the recently-finalized interim stocking court order (see 11/21/08 post), on November 24 the California Department of Fish and Game (CDFG) released lists of California water bodies that either will or will not be stocked between now and the January 11, 2010 release of CDFGs draft fish stocking EIR/EIS. What struck me when I looked over the lists is how few waters state-wide will have their stocking allotments temporarily suspended. Of the 838 waters on the lists, stocking will continue in 91% during the interim period (761 waters will continue to be stocked, stocking in 77 waters is temporarily suspended). This hardly seems cause for alarm.

And yet, as seems always to be the case, several individuals have done their best to inflame the angling community. A
November 30, 2008 story by Tom Stienstra, the outdoor writer for the San Francisco Chronicle, tops the list of irresponsible reporting on this issue. Given Tom's consistent "damn the native species - stock the fish" perspectives (see my 10/17/08 post for one example), I'm hardly surprised. In his recent article, Tom blasts the interim stocking agreement as heralding the end of fishing in many of California's best angling destinations. His article repeatedly asserts that fish stocking at these sites is gone forever, conveniently failing to acknowledge that the stocking moratorium will affect only 77 waters across all of California and only in 2009. Furthermore, given that many of the waters affected by the moratorium are backcountry lakes stocked with fingerling trout, a one year stocking moratorium will have no adverse impacts on these fisheries. This kind of reporting is simply irresponsible and does California's angling community a grave disservice.

Of course, after years of involvement with fish stocking issues I'm used to this sort of junk reporting. About 10 years ago the CDFG proposed removing trout from two lakes in the Eastern Sierra's Big Pine drainage to facilitate the recovery of mountain yellow-legged frogs. Despite the fact that trout fisheries in the majority of the lakes in this drainage were not affected, stories in local and regional newspapers screamed for months about how the removal of trout from these two lakes would have serious negative effects on the area's fisheries and on local economies. Those fish removals are long since complete, and I've seen nary a report of any negative impact whatsoever. And the frogs are thriving. Go figure....

Back to The Mountain Yellow-legged Frog Site.