The proposal should have provided a better summary of the response of kokanee to the initial addition of nutrients to the lake and have more strongly anticipated the expected future response. The following comments are given as feedback so future analysis might be strengthened.

To understand how the kokanee population responds to nutrient addition, it would seem to be necessary to track each cohort (brood year) separately over its lifespan. Data should have been broken out into growth and abundance by age, and before and after maturation, as that gives a better indication of whether there is a strong year class and how well the fish are growing. Although the sponsors indicated that they would age fish and some objectives addressed specific numbers of fish of a given age, it would have been better if they had set a target density, that is number, of fish of a given growth rate or size.There are many problems with assessing kokanee populations because of their short life and semelparity. Density plays a large role in not only pre-maturation growth rate but maturation schedule, post-maturation-decision growth rate, total survival of fish to an age, and thus on year-class strength. The proposal would have benefited from a clearer description of exactly how the sponsors would monitor kokanee response to better clarify if abundance and growth are actually responses or just observations independent of the nutrient addition. The sponsors simply showed that kokanee biomass went up after the years of nutrient addition, without carefully documenting the exact age-specific response or causal links that may be potentially identifiable in their shorter term plankton responses.

The proposal does not indicate how many age-groups of kokanee are present in Dworshak Reservoir, but from papers by Rieman and others it appears to be three. Table 1 of the response gives data for a variety of age-groups and appears to suggest the age-2 fish might be the oldest the project dealt with. This point needs clarification.

Reviewers were expecting to see creel census data presented in the response, but the response indicates no creel surveys were done because of lack of funds. This is an important oversight, but the sponsors note that some creel census will be incorporated into future efforts.

The sponsors repeated that, “The benefits of N supplementation are cumulative, with benefits reaching higher trophic levels in successive years.” This statement is poorly documented. If many of the phytoplankton responses are rapid and zooplankton consume phytoplankton, then why is it assumed that it takes 4-5 years for a kokanee response? How good are the scientific data from Stockner and the work of others leading to this conclusion and why was it not referenced? Understanding the reality of this lag time seems crucial to their claimed observed kokanee response in the past and crucial to the proposed 5-year time frame in this proposal. Without that understanding, the observed year class of kokanee may have been due to more random and unknown year class events/variations that kokanee are well known to exhibit.

In the response, new information was given on kokanee size and numbers from fall seining of prespawning adults collected at index tributaries of the North Fork Clearwater River. These data, presented with minimal detail, appear to contradict previous conclusions based on trawl and acoustic surveys. Figure 4 shows that the number of adult kokanee gathering to spawn increased sharply in 2010, but that average length was the same as before nutrient addition. This is the opposite of what was observed in summer trawl/acoustic sampling when fish density remained about the same, but biomass increased after nutrient addition as compared to pre-nutrient addition. Also, having this "record number" of spawners indicates a high density of age-0 kokanee might be expected for 2011, which is not a desired outcome, and apparently did not occur.

The ISRP has concerns about the interpretation of Objective 3 and the part of Deliverable 3 that involves this seining of index spawning streams and measurement of spawner length, weight, and fecundity of female spawners. The inference here is that spawner carcasses will increase the productivity of these streams and thus benefit resident fishes. The sponsors make the valid point that nutrient addition to lakes has been shown in other studies to increase kokanee growth and biomass. The sponsors, however, plan to measure neither stream productivity nor the response of lower trophic levels and resident stream fishes. For these reasons, the ISRP does not believe that simply measuring spawner abundance in the index streams and inferring a positive response is scientifically warranted. Without basic measures of stream and lower trophic level biomass productivity, it will be difficult to demonstrate any relationship between the reservoir nutrient enrichment actions with increases in stream food web productivity. If the project moves in that direction, comparisons with adjacent reference streams that are not accessible by Dworshak kokanee spawners would seem an important evaluation element.

A lawsuit stopped lake fertilization in 2011, the fourth year of a five-year test, which although a setback for the project was beneficial in terms of monitoring and evaluation. With a cessation of fertilizer input, the sponsors saw a rapid response with blue green algae returning to pre-nutrient enhancement levels. In a nitrogen-limited system, blue green algae can fix nitrogen, and thus outcompete other species that need nitrogen. However, with adequate nitrogen levels, other algal species and their zooplankters predominate over blue green algae, and support a plankton-based kokanee fishery. 

The proposed food web monitoring is critical to evaluating success or failure of the proposed project and addressing both scientific and political concerns. Nevertheless, the ISRP wonders if the monitoring could be reduced in scale and budget and still meet the political and scientific needs for the project? For example, the enclosure experiment could be deleted, as it seems unnecessary and expensive. 

The sponsors did food web work, which should be encouraged, but do not identify the criteria they are going to use for evaluating success nor do they commit to much detail on their fishery goals, in spite of some recent positive results. For example, what kokanee population response is needed to indicate success? The sponsors need a more rigorous presentation of their analysis methods and of existing data to date, including how annual variation in kokanee abundance can be sorted out from treatment response. 

The proposal needs to be more sharply focused on a testable hypothesis. The sponsors argue that fertilization must be repeated, for an additional five years, because four years of data are apparently inconclusive (yet almost no detail regarding results is given to review). A critical question is whether four years of study shows significant enhancement of kokanee. When the population biomass "doubled" at the end of four seasons, were the IDFG management goals for kokanee met? Is it not possible that four years of fertilization were indeed adequate to evaluate a fishery response?

Alternatively, would simply monitoring the kokanee population in summer 2012 answer the question? Further, what really is the question – what kokanee population response is needed to indicate success? The sponsors need to discuss their results (especially kokanee) in light of what has been found in other water bodies. Is the Dworshak work really pioneering?

A response is requested on the following issues: 

1. Provide justification that the duration of the second phase of the study (five years) is long enough to yield conclusive results, given the inevitability of natural variation in kokanee abundance, catch, and spawner counts, and the likelihood that a response of kokanee to the treatment will only be observed in the last one or two years of the study. In their response the sponsors should consider providing a more comprehensive analysis of variability in kokanee abundance and spawner counts prior to the first treatment. In addition it would be helpful if the sponsors provided information on the response of lake biota following cessation of the first set of treatments in 2010.
2. Provide data indicating that pre-treatment kokanee population abundance, angler catch, and fish size did not meet IDFG’s management objectives for the reservoir, and how the objectives were derived.
3. Provide better justification for how the enclosure experiments will directly contribute to understanding kokanee response to nutrient additions in the reservoir. Granted these experiments will shed light on limnological responses over a range of nitrogen concentrations and perhaps assuage public concerns, but what else will they do? For example, will these experiments provide information on trends in lake chemistry, phytoplankton, and zooplankton that cannot be reliably obtained from reservoir samples? Will the experiments provide greater understanding of mechanisms underlying biotic responses to nutrient addition? Will the experiments provide information on kokanee response that is not already known from the fisheries literature? Finally, could the enclosure experiment be reduced in scope or eliminated without compromising the project’s biological goals? 

1. Purpose: Significance to Regional Programs, Technical Background, and Objectives

The proposal identifies three stated objectives: to enhance reservoir productivity, to enhance the kokanee population and to improve nutrient cycling in the river upstream from the reservoir.

The proposed work is to determine if the addition of nitrogen fertilizer to Dworshak Reservoir will enhance the kokanee population and improve the reservoir and upstream fishery. The U.S. Fish and Wildlife Service established a goal of stocking 100,000 lbs of trout annually in Dworshak as mitigation for the loss of resident fisheries (Ecovista et al. 2003, pg 327). However, this goal has only been met three times in the history of the project (IDWR 2000) and recently stocking has been approximately 20,000 pounds annually. Fisheries for non-native kokanee and smallmouth bass have since supplanted trout as the primary fisheries in the reservoir. However, these fisheries continue to be severely limited by reservoir operations. There are no present efforts to mitigate for the loss of historically abundant anadromous fish and marine derived nutrients to the fish and wildlife populations of the North Fork Clearwater ecosystem.

The sponsors present some evidence that the productivity of Dworshak Reservoir has declined, possibly due to operation of the dam, natural aging of the lake, and loss of marine-derived nutrients due to extinction of the salmon run in the North Fork Clearwater River. A five-year pilot nutrient enrichment project was funded in 2007 by BPA. After four years of nutrient addition and data collection the project was suspended in 2010 due to a permitting issue. A positive response in kokanee abundance was seen only in the fourth or last year of the study prior to its cessation. The sponsors are proposing another five year study to more conclusively determine whether nutrient additions to the reservoir will improve kokanee abundance, angler catch, and number of spawners. 

The work is consistent with the Fish and Wildlife Program and the North Fork Clearwater Subbasin Plan where one goal is “assessing where nutrient additions or reductions would be beneficial to focal species.” 

The proposed work would be better justified if the sponsors provided data indicating that pre-treatment kokanee population abundance, angler catch, and fish size did not meet IDFG’s management objectives for the reservoir, and how the objectives were derived. The project introduction states that it "seeks to improve resident fisheries in Dworshak Reservoir through the careful addition of a nitrogen-based fertilizer to the reservoir. In particular, the kokanee population should benefit from improved reservoir productivity and provide a better fishery for anglers. Further, fish and wildlife species in the North Fork Clearwater Subbasin will benefit from nutrients that kokanee transport to spawning tributaries where marine derived nutrients were historically abundant." However, it appears to reviewers that a more accurate description of the current goal is, or should be, to assess if fertilization is sufficiently cost-effective to adopt as regular, annual management.

Objective 3, “Improve nutrient cycling to the North Fork Clearwater River and its tributaries,” is based on the supposition that decomposition of the carcasses of larger runs of kokanee will increase nutrient levels in spawning streams and so benefit stream biota such as bull trout. They also surmise that kokanee fry will provide a food source for bull trout. While possible, this assumption seems at this point to be largely conjecture because no direct evidence was presented that the spawning streams were nutrient limited or that bull trout growth and survival were food limited. Furthermore, the sponsors do not propose to measure nutrient concentrations in the tributaries or determine if any changes in stream biota, including bull trout growth and abundance, have occurred following nutrient addition to the reservoir. Without this information Objective 3 cannot be accomplished. Consequently, either the sponsors should provide an adequate plan to accomplish this objective or the objective should be deleted from the proposed work at this time. 

2. History: Accomplishments, Results, and Adaptive Management (ISRP Review of Results)

In the spring of 2007, the U.S. Army Corps of Engineers (USACE) began applying liquid fertilizer weekly to the reservoir while IDFG monitored the response of the reservoir and kokanee population. Results from the first four years of nutrient supplementation indicated an immediate increase in densities of picoplankton, followed by a reduction in N₂ fixing cyanobacteria concurrent with an increase in the proportion of edible phytoplankton taxa, and an increase in the density and biomass of Daphnia, the preferred forage of kokanee (Scofield et al. 2011). By the fourth year of the project, kokanee were larger than they were in a pre-supplementation year with similar fish densities, and kokanee biomass was twice as high as it had been in recent years for which the sponsors were able to estimate biomass (Wilson et al. in prep). In addition, spawner counts in index streams were the highest on record (Wilson et al. in prep). How much confidence can be placed on the "biomass being twice as high" statistic? Is that likely to be a real, meaningful increase when considering the extent of normal interannual variability? 

A positive response by kokanee was seen only in the last, or fourth, year of the first set of treatments. The sponsors expect the lake to return to pre-treatment conditions following cessation of the first round of nutrient supplementation in 2010. If this occurs and a kokanee response is observed only in the fourth or fifth year of the second set of treatments, as it was in the first set, it could be difficult to determine, with only one or two years of data, whether the response was due to the treatment or to natural variability in lake chemistry, phytoplankton, zooplankton abundance, and kokanee abundance. Given this variability, there is no certainty that a clear, scientifically valid, kokanee response will be evident in a five-year time frame. It seems that a study of much longer duration would be needed to account for natural variability and to provide conclusive results.

ISRP Retrospective Evaluation of Results

The lack of detail given in the proposal on results to date, especially regarding kokanee, made the proposal more difficult to review adequately. The sponsors need to provide more results and discussion than a table and two figures. Data and discussion about creel results including fish size, and catch rates, would have been informative.

3. Project Relationships, Emerging Limiting Factors, and Tailored Questions for Type of Work (hatchery, RME, tagging)

The sponsors will work in collaboration with the USACE’s Dworshak Resident Fish Mitigation Project. The proposed work also is relevant to two BPA funded projects: the Lake Pend Oreille Fishery Recovery Project (199404700) and IDFG’s nutrient restoration project on the Kootenai River that is part of the Kootenai River Resident Fish Mitigation Project (198806500). Relationships with USACE are described, with the USACE covering the cost of the fertilizer and its application, $181K annually, as before.

4. Deliverables, Work Elements, Metrics, and Methods

Most Deliverables are accomplishable and relate directly to the stated Objectives. Standard limnological methods will be used to collect data on lake chemistry, phytoplankton, and zooplankton. Data on the kokanee population will be collected using protocols developed by IDFG. These methods appear sound.

There are six deliverables, including badly-needed public outreach.

Deliverable 1: Monitor limnological conditions of the reservoir – Some monitoring is clearly appropriate but needs to be described in more detail and better justified. Monitoring accounts for nearly half of the annual budget for the proposal. 

The ISRP has commented in its retrospective reports and other reports on the importance of monitoring to evaluate responses to actions; however, the ISRP has also noted that monitoring needs to be targeted so it can answer the needed questions but not consume a disproportionate portion of the project’s budget. We wonder if a scaled down monitoring plan for the food web could adequately provide the project’s M&E needs and increase cost-effectiveness for the project. 

Deliverable 2 is the experimental enclosure experiments. Although interesting, the need for enclosure experiments (Deliverable 2) is uncertain. The central question this proposal addresses is whether the kokanee population will respond positively to nutrient additions and the enclosure experiments will shed little light on this question. Reviewers are not convinced of the need for this task, suggesting it is redundant with work done elsewhere.

The ISRP provided a variety of comments on this proposal and we want to start by explaining our approach to responding.  Responses were specifically requested for three issues and we did this.  However, there were many other comments and questions throughout the document and we also responded to these to assure that ISRP had adequate information to evaluate the proposal. In addition, we noted where changes have been made to the proposal and the references section has been updated to include citations from our responses.  There was a fair bit of repetitiveness in the ISRP comments and questions throughout the document.  We did our best to avoid the same repetition in our responses, but some does exist.  We included our responses directly below each series of ISRP comments so it was clear what questions we were addressing.  We apologize for any repetition and lengthiness of the document, but without more clear direction on how to best respond we chose this approach.

A lawsuit stopped lake fertilization in 2011, the fourth year of a five-year test, which although a setback for the project was beneficial in terms of monitoring and evaluation. With a cessation of fertilizer input, the sponsors saw a rapid response with blue green algae returning to pre-nutrient enhancement levels. In a nitrogen-limited system, blue green algae can fix nitrogen, and thus outcompete other species that need nitrogen. However, with adequate nitrogen levels, other algal species and their zooplankters predominate over blue green algae, and support a plankton-based kokanee fishery. 

The proposed food web monitoring is critical to evaluating success or failure of the proposed project and addressing both scientific and political concerns. Nevertheless, the ISRP wonders if the monitoring could be reduced in scale and budget and still meet the political and scientific needs for the project? For example, the enclosure experiment could be deleted, as it seems unnecessary and expensive. 

RESPONSE: We agree with ISRP that the proposed food web monitoring is critical to evaluating the project. As the project has progressed, we have scaled back monitoring to the extent possible.  However, cost savings have been used to address monitoring needs that have emerged over time.  For example, standard monitoring was scaled back in 2011 and these savings were used to conduct primary production assays. This work yielded some important insights to the response of lower trophic levels that standard monitoring would not have provided. While it is important to monitor phytoplankton density and community composition, these results only yield information on the standing stock, not rates of change. If production has increased for edible taxa as we believe, these increases can be masked by increased grazing. The work performed in 2011 used size fractionation to determine the rate of carbon uptake by different size classes of phytoplankton. Work performed in 2007 suggested that primary productivity increased late in the season with nitrogen addition, but since size fractionation was not performed, it is not known whether these increases took place in the edible or inedible portion of the phytoplankton community. By continuing to scale back our standard monitoring, we will be able to perform additional primary productivity assays and answer critical uncertainties concerning the phytoplankton response to nitrogen supplementation.  However, this adaptive approach to monitoring the food web response does not readily allow for an overall reduction in the monitoring budget.

While we have strived to cut back standard monitoring when possible, we have been careful not to cut back excessively.  Standard monitoring still yields valuable information concerning the plankton communities. It should be noted that with phytoplankton in particular, life cycles for these organisms can be shorter than the period between sampling events. Phytoplankton blooms can be missed even with twice monthly sampling.  Once monthly sampling, particularly during the summer, is virtually guaranteed to miss blooms, thus giving an inaccurate picture of the true community composition.  We have consulted with limnologists Darren Brandt and Dr. John Stockner on this issue and have been advised to maintain twice monthly sampling.

Another consideration is the sampling requirements in the NPDES permit issued by EPA. While we have been able to cut back on some monitoring, the newly acquired permit has resulted in some additional requirements. For example, we are now required to test for total nitrogen, total ammonia, pH, turbidity and micro-zooplankton.  Monitoring needs to be maintained at a level that allows permit compliance to be evaluated.

While the enclosure experiment represents a fairly large proportion of the project budget, we believe it will yield critical information.  See below for detailed justification.

Overall, we believe that the proposed monitoring is necessary to adequately evaluate project success.  We will continue to critically evaluate monitoring activities and results and adaptively modify our monitoring when appropriate.  For a project of this scale, we believe the monitoring budget is not excessive and designed in an efficient manner.  If we ultimately determine that nutrient addition should become a long-term implementation strategy, then we fully expect to scale back monitoring.  Until then, it is important to collect data that will allow for sound decisions to be made regarding implementation of this management strategy.

The sponsors did food web work, which should be encouraged, but do not identify the criteria they are going to use for evaluating success nor do they commit to much detail on their fishery goals, in spite of some recent positive results. For example, what kokanee population response is needed to indicate success? The sponsors need a more rigorous presentation of their analysis methods and of existing data to date, including how annual variation in kokanee abundance can be sorted out from treatment response. 

RESPONSE: The ISRP would like more detail about our criteria for evaluating success.  In our original proposal, we included time-specific and quantifiable objectives, as advocated by Barber and Taylor (1990), for each trophic level.  These include increases in the density of picoplankton, proportion of edible phytoplankton, and biomass of Daphnia (see Objective 1).  For the kokanee population, we included objectives (Objective 2, 3) to increase the biomass and size at a given density.  The objectives established for each trophic level serve as benchmarks for gauging project success. 

As recognized by ISRP, the level of natural variation seen at all trophic levels makes the evaluation of this project challenging. This is particularly so for kokanee, a species with naturally variable and often cyclic densities.  While the ultimate goal is to provide a benefit to the kokanee fishery, we believe that evaluating the response of all trophic levels to fertilization is the appropriate way to evaluate project success.  Fertilization is intended to have a bottom-up effect on the food web.  Each trophic level should have a predictable response to fertilization and looking at responses at all trophic levels, rather than just for kokanee, will increase our ability to evaluate whether the project is having intended effects.  However, because of the importance of the kokanee response, we intend to use specific analysis methods for evaluating their response.  Initial attempts to model kokanee size as a function of abundance have yielded significant models. However, this modeling requires using each year as a single data point.  Assuming this proposal is funded, we will acquire enough data points to incorporate significant covariates into the models. Another approach that we intend to employ is the use of mixed effect models (Weisberg et al. 2010) which can be used to detect the effects of covariates, such as fish density and forage availability, on fish growth. Since fish scales can provide data on growth increments for years in which trawl surveys were not performed, this method will further increase the number of years for which we have data to make these comparisons.

We seek to enhance the Dworshak Reservoir fishery and criteria in Objective 2 were developed based on fishery performance desires.   There are two ways to enhance the performance of the fishery through the kokanee population.  The first is to increase the density of kokanee of a given size.  More fish should result in higher catch rates and attract more anglers to the fishery.  The second would be to increase the size of the fish at a given density. Reiman and Maiolie (1995) determined that larger kokanee are more vulnerable to sport anglers. Therefore increasing the size of the fish at a given density should result in higher catch rates. Larger fish are also more appealing to anglers.  Since it is not practical to manage fish density in Dworshak Reservoir, it makes more sense to maximize fish size at a given density. Catch rates for kokanee averaged 0.8 fish per hour between 2003 and 2004. Catch rates in the late-1980’s and early-1990’s averaged 1.3 fish per hour. In order to return the fishery to the performance of this time period, we would need a 67% increase in catch rates. Reiman and Maiolie (1995) determined that the relative ‘catchability’ of kokanee increases approximately 27% with each 10 mm increase in total length.  Therefore, an increase of 25 mm at a given density should increase catch rates by 67%.  In reviewing our criteria for Objective  2, we realized that the targets of  increasing total length by 20 mm and average catch rate by 0.7 fish per hour were not ideal.  These targets were based on fishery performance in the 2000’s, rather than in the late-1980’s and early-1990’s.  After further consideration, we believe Objective 2 should call for a 25 mm increase in total length and an average catch rate of 1.3 fish per hour.  These criteria will provide fishery performance that is more reflective of what the reservoir provided when productivity was higher.  Thus, we modified Objective 2 in the revised proposal.

The proposal needs to be more sharply focused on a testable hypothesis. The sponsors argue that fertilization must be repeated, for an additional five years, because four years of data are apparently inconclusive (yet almost no detail regarding results is given to review). A critical question is whether four years of study shows significant enhancement of kokanee. When the population biomass "doubled" at the end of four seasons, were the IDFG management goals for kokanee met? Is it not possible that four years of fertilization were indeed adequate to evaluate a fishery response?

RESPONSE: In regard to hypothesis testing, the ISRP understand that, with the exception of the proposed mesocosm experiment (see below), the proposed project is observational in nature.  There can be no replicate of Dworshak Reservoir being fertilized.  We do have two control reaches of the reservoir where inlet arms are not fertilized and do not readily mix with the main reservoir; however, these are not true controls as would occur in an experiment.  We can develop and test a research hypothesis (sensu Romesburg 1981), but formal null hypothesis testing is problematic.  Our stated research hypothesis is that five years of nutrient additions into Dworshak Reservoir will produce acceptable increases in the kokanee fishery.  In 2010, we observed a significant increase in kokanee biomass, as well as mean length and weight, at a density similar to that observed in 2006. This response was nearly sufficient to meet IDFG management goals at this fish density. However, observed increases represent only a single year and earlier results were much smaller. While we can safely conclude that these metrics increased, to conclude that these increases were due solely to nutrient enhancement is difficult to justify, as the earlier ISRP comments regarding kokanee population variability attests.  Because of the unexpected permit issue, we have an unplanned but perhaps fortuitous opportunity (as ISRP notes in their first comment of this review) to repeat the pilot phase of this project.  This sort of start-stop-start study design, also known as an interrupted time series design, should be beneficial for evaluating the response of all trophic levels to fertilization.  We already observed negative food web responses after halting fertilization.  Documenting a subsequent re-building of food web responses after resuming fertilization would greatly increase our confidence that observed responses are not spurious.  Such an approach seems optimal given the necessary observational nature of this study.  Regardless, we believe that there is a need for additional data before making a final decision on fertilization.  We also believe such information will assure that the project is accepted by the public.

In the above comment, ISRP states that we provided almost no detailed results.  The entire Major Accomplishments section of the report summarizes our results from the past five years.  These results were supported with citations to annual reports written by both IDFG personnel and the project consultant.  We anticipated that these documents would be referenced by ISRP if more in-depth results and discussion were desired.  In an attempt to provide the ISRP with more details, we added to our results description in the Major Accomplishments section of the proposal.  But, this was kept to a minimum because we assume ISRP desires concise proposals that do not include entire segments of annual reports.  If this is still not sufficient, we would be happy to provide reviewers with copies of any reports that are cited in the proposal.

Alternatively, would simply monitoring the kokanee population in summer 2012 answer the question? Further, what really is the question – what kokanee population response is needed to indicate success? The sponsors need to discuss their results (especially kokanee) in light of what has been found in other water bodies. Is the Dworshak work really pioneering?

RESPONSE: Monitoring the kokanee population in 2012 will not allow us to determine whether fertilization should be implemented into the future.  As noted in our proposal, the lack of fertilization at the end of the 2010 field season and entire 2011 field season allowed the reservoir food web to essentially return to pre-treatment conditions.  Therefore, monitoring kokanee in 2012 will not provide additional perspective on their response to fertilization.  We specified objectives in our proposal for all trophic levels, including kokanee, that are time-specific and quantifiable.  Meeting these objectives will indicate project success.

Dworshak is not the pioneering work for using lake fertilization to enhance a kokanee population. The longest running project is the Kootenay Lake, B.C. fertilization project, which is entering its 21^st year. The Kootenay Lake kokanee population responded with a near tripling of kokanee biomass during fertilized years, as compared to six years pre-fertilization. Long term means for kokanee length and weight did not change dramatically, but the mean length and weight are maintained at a much higher fish density. While Kootenay Lake serves as a nice model for comparison, it does differ from Dworshak Reservoir.  Most obvious is that Kootenay Lake is a natural lake with high water retention time and stable water levels.  Dworshak is a reservoir with extreme seasonal water level fluctuations and a short retention time (about 10 months).  Another difference is that most fertilized areas of Kootenay Lake are supplemented with both nitrogen and phosphorus, whereas Dworshak has been limited to nitrogen supplementation since the third year.  Because Kootenay Lake and most other fertilization projects occur on natural lakes rather than reservoirs, we cannot simply expect Dworshak Reservoir to exhibit the same responses.  That said, there are many things we have learned by comparing our results to these projects and frequently communicating with biologists on these projects.  The successes achieved elsewhere increase our confidence that nutrient addition is worth pursuing for Dworshak Reservoir.  While lake fertilization is not a pioneering concept, the primary question for IDFG as a management agency is whether nutrient addition will benefit this reservoir fishery.  Nonetheless, we believe the mesocosm experiment is indeed pioneering and has garnered considerable excitement among limnologists studying the effects of nutrients on blue-green algae.

A response is requested on the following issues: 

1. Provide justification that the duration of the second phase of the study (five years) is long enough to yield conclusive results, given the inevitability of natural variation in kokanee abundance, catch, and spawner counts, and the likelihood that a response of kokanee to the treatment will only be observed in the last one or two years of the study. In their response the sponsors should consider providing a more comprehensive analysis of variability in kokanee abundance and spawner counts prior to the first treatment. In addition it would be helpful if the sponsors provided information on the response of lake biota following cessation of the first set of treatments in 2010.

RESPONSE: The amount of natural annual variation at all trophic levels within Dworshak Reservoir presents a challenge in assessing the response of this system to nitrogen addition with a high degree of certainty. Environmental factors, such as precipitation, solar radiation and temperature, are drivers of reservoir productivity and plankton communities. Kokanee growth is dependent on both forage availability and fish density (Rieman and Myers 1992). Kokanee abundance can be influenced by entrainment, as well as a variety of natural factors. In these situations, it can take considerable trend data to separate natural variation from the effects of nitrogen supplementation. Furthermore, much of the data collected on plankton communities, while important to management of the fertilizer applications, only yields information on the standing stock of these populations, not rates of change. For example, increased production of edible phytoplankton can be masked by increased grazing by zooplankton. These challenges are compounded by the limited amount of pre-treatment data, a lag time to observe effects at successive trophic levels, and a stoppage late in the fourth year of treatment. Due to these factors, there remain uncertainties as to the effectiveness of the project.  Each additional year of data, however, has given us a better understanding of how the whole system is responding.   Additionally, we have adaptively modified our monitoring and research to fill in knowledge gaps that have been identified along the way.  Based on our current understanding of the reservoir’s response to fertilization, we believe that five additional years of study using a combination of previously used and new methods is necessary.  While we cannot make guarantees as to the exact timeframe that will be necessary to make a final determination, we think five years is likely to be adequate.

Two new approaches will allow us to better assess the food web response. In 2011, we contracted Darren Brandt of Advanced Eco-Solutions to conduct primary productivity research. This included size fractionation to determine the levels of productivity (i.e., carbon uptake) accounted for by three size groups of phytoplankton. Since these surveys give us information about the rates of change within the phytoplankton community, rather than just information on the standing stock, they are expected to yield greater insight to the actual response of the phytoplankton community to primary production. Furthermore, size fractionation will allow us to determine whether productivity is being channeled into phytoplankton which are of a size that zooplankton can graze on efficiently. Results to date suggest that late-season productivity may be increased by nitrogen addition, and that productivity is shifted toward the larger, mostly inedible portion of the phytoplankton community once available nitrogen has been exhausted.

Primary productivity research conducted to date constitutes a survey, as there are no real controls or replicates. As noted earlier, it can take multiple years of trend data to sort out natural variation from a treatment effect and assigning causation is problematic. The proposed enclosure study would provide experimental data that could be used to determine the effects of differing levels of nitrogen addition using replicate treatments while environmental conditions are essentially the same. Doing so will not only allow us to prove causation of the observed effects, but allow us to measure the response from the nitrogen additions separate from environmental variation.  Additional justification for the enclosure experiments is provided in our response to #3 (see below).

While the two above approaches are likely to yield results for plankton communities, they offer no direct help in assessing a response to the kokanee population. The metric of most interest for the kokanee population is growth, measured in terms of annual changes in length and weight. Trawl surveys are currently our best source of data to evaluate fish size and growth.  Unfortunately, trawl surveys were not conducted on a consistent basis over the decade prior to lake fertilization. Furthermore, multiple surveys needed to assess seasonal growth only exist for one year prior to fertilization. To date, assessing the effects of fertilizer on fish growth has been limited to comparing fish size in years of similar fish density. While this approach has yielded insight, there are a limited number of years for which we can make comparisons.  A better approach is to analyze growth using kokanee scale samples archived from trawl surveys dating back to 2003. We can reconstruct the growth history of an individual through length back-calculations, thereby yielding information on growth for years in which fish were not collected. We are currently in the process of acquiring digital images of a random sample of kokanee scales from each year we performed trawl surveys. Once complete, these images will be analyzed with FishBC 3.0 software to obtain growth intervals for kokanee by age and year. Growth intervals will then be evaluated using a mixed effects model developed by Weisberg et al. (2010). We will incorporate covariates into these models to account for fish density and test for effects due to treatment or zooplankton abundance. A significant relationship between fish growth and forage availability could be used in conjunction with our knowledge of the food web response to relate changes in fish growth to nitrogen supplementation. We are confident this approach will allow us to determine the effect of nitrogen additions on kokanee growth with a high degree of certainty.

We added information to the Major Accomplishments section of the proposal that we hope will provide the requested details regarding the response observed following cessation of fertilization.

1. Provide data indicating that pre-treatment kokanee population abundance, angler catch, and fish size did not meet IDFG’s management objectives for the reservoir, and how the objectives were derived.

RESPONSE: Kokanee management in Dworshak Reservoir has been problematic due to large fluctuations in abundance, due in large part to entrainment, coupled with declining reservoir productivity. In the late 1980’s and early 1990’s, creel surveys indicate that the reservoir was capable of sustaining harvest rates in excess of 1 fish/hour on a consistent basis (range = 0.84 to 1.61 fish/hour; mean = 1.3 fish per hour). Creel surveys in the early 2000’s indicated harvest rates below one fish per hour (range = 0.70 to 0.86 fish per hour; mean = 0.8 fish per hour). Since 1993, summer draw downs have limited entrainment to years of high runoff. This has resulted in swings from years of high abundance and small fish to years of low abundance and large fish. In 2006, kokanee reached record levels of abundance for Dworshak Reservoir. However, the small size of these fish led to dissatisfaction among anglers and the poor condition likely led to poor survival.

Objectives previously stated in our proposal were based on the IDFG 2007-2012 Fish Management Plan, which were based on expectations derived from recent creel data. In retrospect, it makes more sense to develop fishery performance objectives for the project based on past performance of the fishery. Historical data suggests that the performance of the fishery over the past decade has declined from what it was earlier on and that the fishery should be capable of supporting higher catch rates. Therefore, we modified the fishery objective in our proposal, returning the harvest rate to the mean harvest rate of 1.3 fish/hour from the late 1980’s and early 1990’s.

Catch rates for kokanee are a function of both fish density and fish size, which is heavily influenced by fish density. All other factors being equal, the more fish of a harvestable size in the reservoir, the more likely it is for an angler to catch one at a given moment. However, the more fish there are in the reservoir, the smaller the mean size of those fish will be. Research published by Reiman and Maiolie (1995) indicates that the relative ‘catchability’ of kokanee increases with increasing size. Therefore, there is a theoretical density that should maximize angler catch. For most Northern Idaho lakes and reservoirs this was estimated to be between 30 and 50 adult kokanee per hectare. However, this theoretical density can also change with reservoir productivity. Since kokanee abundance in Dworshak Reservoir is highly variable and is at present not practical to manage for a target density, it stands to reason that maximizing catch at a given fish density by increasing the size, and therefore catchability, at a given density would give the best chance of enhancing the performance of the fishery.

Increasing mean catch rates from those of the early 2000’s to those of the late 1980’s and early 1990’s would require a 67% increase.  Reiman and Maiolie (1995) found that kokanee in Northern Idaho lakes and reservoirs were approximately 27% more ‘catchable’ for each 10 mm in TL. Therefore, increasing the size of age-2 and older kokanee by 25 mm TL at a given density should theoretically result in a 67% improvement in catch rates.

1. Provide better justification for how the enclosure experiments will directly contribute to understanding kokanee response to nutrient additions in the reservoir. Granted these experiments will shed light on limnological responses over a range of nitrogen concentrations and perhaps assuage public concerns, but what else will they do? For example, will these experiments provide information on trends in lake chemistry, phytoplankton, and zooplankton that cannot be reliably obtained from reservoir samples? Will the experiments provide greater understanding of mechanisms underlying biotic responses to nutrient addition? Will the experiments provide information on kokanee response that is not already known from the fisheries literature? Finally, could the enclosure experiment be reduced in scope or eliminated without compromising the project’s biological goals? 

RESPONSE: As the ISRP recognizes, these mesocosm experiments will provide insight as to how varying levels of nitrogen addition will affect the plankton communities within the reservoir. Most importantly, the availability of replications will allow us to separate the effect of nitrogen addition to the plankton communities from environmental variation and assign causation to these effects. This information will be important to the project for a number of reasons. First, we have encountered resistance from a small, but vocal, minority of the public who believe that fertilizer is the cause of blue-green algae within the reservoir which previously existed but was largely unnoticed. These experiments will allow us to conclusively demonstrate with statistical rigor (including P-values) the effect of nitrogen additions on blue-green algae in the reservoir.  We believe such data will be quite helpful for overcoming public concerns about blue-green algae.  The above ISRP comment alluded to this positive aspect of the enclosure experiment, but we ask the ISRP to consider the importance of information garnered from such a simple design for educating a public that lacks biological backgrounds.  ISRP should note that this project is a cost-share with the Corps of Engineers (USACE).  Secondly, if this project is successful, they are likely to provide funding for fertilization into the future.  However, USACE objectives for Dworshak Reservoir focus more on water quality and recreation than fishery performance so their decision to move forward with fertilization depends on addressing blue-green concerns.  A final reason for the enclosure experiments is to fine-tune our understanding of how much nitrogen needs to be added to achieve objectives. If current levels of nitrogen supplementation do not allow project objectives to be met, the enclosure experiments will allow us to ascertain how much additional nitrogen would need to be added to achieve these goals. Alternatively, these experiments will allow us to determine if the project is adding nitrogen in excess of what is needed to achieve project objectives, thereby allowing the applications to be scaled back and reduce costs. Our current limnological surveys alone are not sufficient to make a good determination on the optimal amount of nitrogen to add to the reservoir.

While these experiments are not designed to make any direct measurements of the effect to the kokanee population, they will be useful for determining the level of increased forage for kokanee within the reservoir. These results may be useful for coupling with the results of mixed effects models (described in an earlier response) to determine the level of response we should expect to see from the kokanee population based on the level of response of the forage base to nitrogen addition.

With these considerations in mind, we feel it is important to retain the enclosure experiments we are proposing and maintain a reasonable level of food web monitoring until definitive conclusions can be drawn. While limnological monitoring has been scaled back in some respects, such as elimination of hypolimnetic sampling, we have channeled our efforts into other avenues that yield critical information, such as primary production. Once definitive conclusions have been drawn, sampling effort can be scaled back to what is necessary under the NPDES permit and for in-season management of the fertilizer applications. While cutting the proposed monitoring may result in short-term savings, it would ultimately be more expensive to conduct this additional five year pilot project only to end up with inconclusive results.  Evaluation of the nutrient supplementation project for Dworshak Reservoir is a challenging task when the complexity of the system and high degree of annual variation is considered.  Thus, the ISRP concerns about our ability to arrive at a definitive conclusion at the end of five years are fair.  However, we strongly believe enclosure experiments will increase our ability to make an informed decision in that time frame.  And, information these experiments provide will be critical for maintaining the public support necessary for the project to succeed.

1. Purpose: Significance to Regional Programs, Technical Background, and Objectives

The proposal identifies three stated objectives: to enhance reservoir productivity, to enhance the kokanee population and to improve nutrient cycling in the river upstream from the reservoir.

The proposed work is to determine if the addition of nitrogen fertilizer to Dworshak Reservoir will enhance the kokanee population and improve the reservoir and upstream fishery. The U.S. Fish and Wildlife Service established a goal of stocking 100,000 lbs of trout annually in Dworshak as mitigation for the loss of resident fisheries (Ecovista et al. 2003, pg 327). However, this goal has only been met three times in the history of the project (IDWR 2000) and recently stocking has been approximately 20,000 pounds annually. Fisheries for non-native kokanee and smallmouth bass have since supplanted trout as the primary fisheries in the reservoir. However, these fisheries continue to be severely limited by reservoir operations. There are no present efforts to mitigate for the loss of historically abundant anadromous fish and marine derived nutrients to the fish and wildlife populations of the North Fork Clearwater ecosystem.

The sponsors present some evidence that the productivity of Dworshak Reservoir has declined, possibly due to operation of the dam, natural aging of the lake, and loss of marine-derived nutrients due to extinction of the salmon run in the North Fork Clearwater River. A five-year pilot nutrient enrichment project was funded in 2007 by BPA. After four years of nutrient addition and data collection the project was suspended in 2010 due to a permitting issue. A positive response in kokanee abundance was seen only in the fourth or last year of the study prior to its cessation. The sponsors are proposing another five year study to more conclusively determine whether nutrient additions to the reservoir will improve kokanee abundance, angler catch, and number of spawners.

RESPONSE: In the above comment ISRP noted that we provided “some evidence” that productivity has declined.  We wanted to be more clear that there is extensive evidence that productivity of Dworshak Reservoir has declined beyond what can be accounted for by natural aging of the reservoir. This has been documented in several reports leading up to the nutrient project.  New reservoirs typically undergo a boom period when they are first impounded. This is the result of terrestrial organic material that becomes inundated, decays, and releases nutrients into the water. Once this source of nutrients is exhausted, typically within four to eight years, the productivity of the reservoir will level off at a point where productivity is a result of the nutrients coming from the watershed that supplies the reservoir. Nutrient levels and resultant productivity in Dworshak reservoir has continued to decline well beyond this stage. Continued oligotrophication was documented by Maiolie et al. (1992) during the late 1980’s and early 1990’s, nearly 20 years after the reservoir was created. Reservoir productivity decline was also identified as a major concern for fisheries management in a review by Bennett (1997). A thorough review of the limnological history and assessment of the reservoir provided by Stockner and Brandt (2005) led to the initiation of the current nutrient program.  We added information to the proposal, including a figure showing the decline in nutrient concentrations and N:P ratios since the reservoir was impounded.  We thought these details might help ISRP better understand the extent of the datasets documenting the change in reservoir productivity that has occurred over time.

The work is consistent with the Fish and Wildlife Program and the North Fork Clearwater Subbasin Plan where one goal is “assessing where nutrient additions or reductions would be beneficial to focal species.” 

The proposed work would be better justified if the sponsors provided data indicating that pre-treatment kokanee population abundance, angler catch, and fish size did not meet IDFG’s management objectives for the reservoir, and how the objectives were derived. The project introduction states that it "seeks to improve resident fisheries in Dworshak Reservoir through the careful addition of a nitrogen-based fertilizer to the reservoir. In particular, the kokanee population should benefit from improved reservoir productivity and provide a better fishery for anglers. Further, fish and wildlife species in the North Fork Clearwater Subbasin will benefit from nutrients that kokanee transport to spawning tributaries where marine derived nutrients were historically abundant." However, it appears to reviewers that a more accurate description of the current goal is, or should be, to assess if fertilization is sufficiently cost-effective to adopt as regular, annual management.

RESPONSE: See our earlier response to Issue #2 for a description of IDFG kokanee management objectives.

If we understand correctly, the ISRP suggests that the current project goal should be re-structured to evaluate project cost-effectiveness.  While we agree that long-term implementation costs are an issue to be considered by decision-makers, we do not believe these costs need to be directly evaluated.  That said, a general economic review of the situation seems appropriate.  The proposed project, quite small by BPA-funded study standards, seeks an average of $275,000 per year to evaluate the potential for fertilization to improve a diminished fishery that was valued at just under $6 million in 2003 (most recent IDFG economic survey).  The requested funds are intended to mitigate for losses suffered following the construction of Dworshak Dam, which blocked access to one of the most productive drainages in the Columbia Basin for anadromous fish.  If fertilization is adopted as a regular management action, we anticipate that monitoring costs would decrease significantly.  Further, the economic benefits expected to occur if this project successfully meets its objectives would likely far surpass the modest expense for fertilization.  Overall, we believe that this project can already be deemed cost-effective because costs are small relative to the economic value that the resident fishery provides and the mitigation responsibility that exists because of the loss of marine-derived nutrients from the drainage.

Objective 3, “Improve nutrient cycling to the North Fork Clearwater River and its tributaries,” is based on the supposition that decomposition of the carcasses of larger runs of kokanee will increase nutrient levels in spawning streams and so benefit stream biota such as bull trout. They also surmise that kokanee fry will provide a food source for bull trout. While possible, this assumption seems at this point to be largely conjecture because no direct evidence was presented that the spawning streams were nutrient limited or that bull trout growth and survival were food limited. Furthermore, the sponsors do not propose to measure nutrient concentrations in the tributaries or determine if any changes in stream biota, including bull trout growth and abundance, have occurred following nutrient addition to the reservoir. Without this information Objective 3 cannot be accomplished. Consequently, either the sponsors should provide an adequate plan to accomplish this objective or the objective should be deleted from the proposed work at this time. 

RESPONSE: The ISRP is correct that we do not have empirical data to support the assumed benefits to resident fish from increased biomass and density of spawning kokanee in the North Fork Clearwater Subbasin. However, there is a considerable amount of evidence from the literature to suggest that this would indeed be the case. Wipfli et al. (2003) and Bilby et al. (1998) both documented increased growth rates to fishes in streams that were supplemented with salmon carcasses. Janetski et al. (2009) reported that live salmon had a stronger effect on stream productivity and resident fish than carcasses or analogs. Besides stimulating primary production, spawning salmon create disturbances that are beneficial to resident fishes (Janetski et al. 2009) and provide food sources such as eggs (Wipfli et al. 2003) and juveniles. While nutrient limitation has not been studied in the North Fork Clearwater Subbasin, Snyder et al. (2002) determined that other locations in the Clearwater Subbasin are co-limited by N and P. Due to the underlying geology, Idaho streams tend to be nutrient limited (Snyder et al. 2002; Sanderson et al. 2008). Anadromous salmon have been demonstrated to play an important role in the stream ecology and growth of resident fish throughout the Pacific Northwest. Therefore, it stands to reason that the loss of anadromous fish would result in a negative effect on resident fish in the North Fork Clearwater Subbasin. While we agree that it would be desirable to study nutrient limitation and subsequent limitations on the survival and growth of resident fishes in the North Fork Clearwater, this work would result in considerable added expense in addition to the work we are currently proposing. Since the current project is primarily intended to benefit the ecology and fish communities within the reservoir, we believe efforts should focus on evaluating effects within the reservoir. Evaluating increases to the abundance and biomass of spawning kokanee from surveys within the reservoir will not result in any additional project costs, yet will provide some indication of whether increased nutrients are being transported upstream.  Similarly, monitoring kokanee spawners at index sites in upstream tributaries is already being done as part of the reservoir evaluation and provides some measure of increased biomass being transported upstream.  Also, IDFG has conducted standardized snorkel surveys since the early-1970’s for westslope cutthroat and other resident fish in the North Fork Clearwater and several large tributaries (work not associated with this project) that should prove useful for evaluating the upstream fish response.  In combination, these approaches will provide data to generally assess whether nutrients are being transported upstream and if resident fish are responding favorably.  Given budget considerations, we believe this approach is adequate at this time.  If we determine that questions regarding the effects of upstream nutrient transport on resident fish need further evaluation, we can consider pursuing funds for more rigorous work in the future.

2. History: Accomplishments, Results, and Adaptive Management (ISRP Review of Results)

In the spring of 2007, the U.S. Army Corps of Engineers (USACE) began applying liquid fertilizer weekly to the reservoir while IDFG monitored the response of the reservoir and kokanee population. Results from the first four years of nutrient supplementation indicated an immediate increase in densities of picoplankton, followed by a reduction in N₂ fixing cyanobacteria concurrent with an increase in the proportion of edible phytoplankton taxa, and an increase in the density and biomass of Daphnia, the preferred forage of kokanee (Scofield et al. 2011). By the fourth year of the project, kokanee were larger than they were in a pre-supplementation year with similar fish densities, and kokanee biomass was twice as high as it had been in recent years for which the sponsors were able to estimate biomass (Wilson et al. in prep). In addition, spawner counts in index streams were the highest on record (Wilson et al. in prep). How much confidence can be placed on the "biomass being twice as high" statistic? Is that likely to be a real, meaningful increase when considering the extent of normal interannual variability? 

RESPONSE: Since the proposal was submitted, bootstrap confidence intervals have been derived for kokanee biomass in each year shown in Figure 3 of the accomplishments section. The increase in biomass during the fourth year is highly significant.  Additionally, biomass can be evaluated in the context of abundance.  During both 2006 (pre-treatment) and 2010, kokanee abundance was similar, yet biomass was nearly 50% higher in 2010.  This suggests that kokanee growth was improved at a similar fish density.

A positive response by kokanee was seen only in the last, or fourth, year of the first set of treatments. The sponsors expect the lake to return to pre-treatment conditions following cessation of the first round of nutrient supplementation in 2010. If this occurs and a kokanee response is observed only in the fourth or fifth year of the second set of treatments, as it was in the first set, it could be difficult to determine, with only one or two years of data, whether the response was due to the treatment or to natural variability in lake chemistry, phytoplankton, zooplankton abundance, and kokanee abundance. Given this variability, there is no certainty that a clear, scientifically valid, kokanee response will be evident in a five-year time frame. It seems that a study of much longer duration would be needed to account for natural variability and to provide conclusive results.

RESPONSE: While the kokanee response in 2010 was certainly the highest level of response, at least in terms of biomass, length, and weight at a given density, it was not the only year in which a response was seen. Growth rates, in terms of change in the mean length during a growing season, were higher in 2007 and 2008 than in 2004 (the only pre-supplementation year with multiple trawl surveys). While 2004 and 2008 had very similar kokanee densities, kokanee weight and biomass were significantly higher in 2008. One aspect of the response that will need more time to be sorted out is whether the level of response increased over time, or if the level of response increased with increasing density.

While the high degree of natural variation makes evaluating the kokanee response challenging, there are approaches we are taking to accomplish this. For one, we are monitoring the response for each trophic level. In order for nitrogen supplementation to result in a kokanee response, it will first have to result in increased forage for kokanee. Determining the response of the lower trophic levels will help us evaluate whether the system as a whole is responding as expected, and if it is resulting in an increased forage supply for kokanee.  From our perspective, such a holistic approach seems appropriate when dealing with an observational study.  Also of importance, the “start, stop, start” design we have inherited will provide additional confidence in the eventual conclusion, particularly if the second pilot period provides similar limnological and fishery responses. 

A key to evaluating the kokanee response will be developing significant models that are capable of predicting fish growth as a function of abundance and forage availability. These models could then be combined with our knowledge of how the forage base responds to nitrogen supplementation to, in turn, predict how nitrogen supplementation will affect fish growth.  More details about modeling approaches are provided in an above response.

We are a bit confused by contrasting comments by ISRP regarding the time frame necessary to evaluate project success.  Earlier comments seem to suggest that we already have enough information to implement fertilization, while the above comment questions whether an additional five years is sufficient.  There are circumstances that could prevent making an implementation decision by the end of the next pilot period.  For instance, a major runoff event could lead to major entrainment of kokanee as occurred in 1997.  Thus, we cannot guarantee that the proposed time frame is long enough.  However, combined with results from the previous five years and new research that has been included, we believe that the time frame proposed is likely to provide results that allow an informed decision to me made.

ISRP Retrospective Evaluation of Results

The lack of detail given in the proposal on results to date, especially regarding kokanee, made the proposal more difficult to review adequately. The sponsors need to provide more results and discussion than a table and two figures. Data and discussion about creel results including fish size, and catch rates, would have been informative.

RESPONSE: The results provided in the proposal, particularly in the Major Accomplishments section, were intended to be a summary of our results to date.  These results were supported with citations to annual reports written by both IDFG personnel and the project consultant.  We anticipated that these documents would be referenced by ISRP if more in-depth results and discussion were desired.  In an attempt to provide the ISRP with more details, we added to our results description in the Major Accomplishments section of the proposal.  Also, we would be happy to provide reviewers with copies of any reports that are cited in the proposal.

A desire for creel results is stated by ISRP.  We were not able to conduct creel work during past years due to budget limitations.  We strongly believe that a creel survey (see DELV-4) will be necessary in the final two years of the pilot study to assess whether the project has met fishery performance objectives.  We hope that the need for creel data is recognized and met with ISRP approval.

3. Project Relationships, Emerging Limiting Factors, and Tailored Questions for Type of Work (hatchery, RME, tagging)

The sponsors will work in collaboration with the USACE’s Dworshak Resident Fish Mitigation Project. The proposed work also is relevant to two BPA funded projects: the Lake Pend Oreille Fishery Recovery Project (199404700) and IDFG’s nutrient restoration project on the Kootenai River that is part of the Kootenai River Resident Fish Mitigation Project (198806500). Relationships with USACE are described, with the USACE covering the cost of the fertilizer and its application, $181K annually, as before.

4. Deliverables, Work Elements, Metrics, and Methods

Most Deliverables are accomplishable and relate directly to the stated Objectives. Standard limnological methods will be used to collect data on lake chemistry, phytoplankton, and zooplankton. Data on the kokanee population will be collected using protocols developed by IDFG. These methods appear sound.

There are six deliverables, including badly-needed public outreach.

RESPONSE: We would like ISRP to be aware that public outreach has not been ignored in past years.  We put a great deal of effort, seemingly exhaustive at times, into keeping the public informed.  We have presented information to numerous civic groups each year and hold an annual public meeting in Orofino that is specifically structured to update the community about project activities and results.  Additionally, we regularly communicate project information using the local media and via direct interaction with members of the public.  Because of the project interruption that was brought about by public opposition, it is tempting to conclude that public outreach is lacking.  However, we hope ISRP can understand that only a few vocal individuals were the drivers behind this issue and that overall support for this project is quite good.

Deliverable 1: Monitor limnological conditions of the reservoir – Some monitoring is clearly appropriate but needs to be described in more detail and better justified. Monitoring accounts for nearly half of the annual budget for the proposal. 

RESPONSE: Monitoring costs are, admittedly, a relatively expensive part of this project. Many of the lab analyses used, particularly for biological samples, are labor intensive and therefore samples are relatively expensive. Reducing the amount of samples that are analyzed could reduce these costs considerably. However, the life span of these organisms is typically shorter than the interval between the current sampling. Phytoplankton blooms in particular, can last less than a couple of weeks. Reducing the frequency of the biological sampling to monthly, particularly in the summer, would cause blooms to go undetected and likely result in an inaccurate assessment of the plankton communities.

Monitoring is described in detail in the annual reports and QAPP, which are cited in the proposal.  Additionally, monitoring details for this deliverable are clearly described in MonitoringMethods.org.  It was recently brought to our attention that ISRP may not have been able to view our Methods on the website because they were in “draft” state and not viewable.  Instructions indicated that this was satisfactory, but apparently it caused problems during review.  We have since advanced all of our Methods to “proposed” state in MonitoringMethods.org and they should now be viewable by ISRP.

The ISRP has commented in its retrospective reports and other reports on the importance of monitoring to evaluate responses to actions; however, the ISRP has also noted that monitoring needs to be targeted so it can answer the needed questions but not consume a disproportionate portion of the project’s budget. We wonder if a scaled down monitoring plan for the food web could adequately provide the project’s M&E needs and increase cost-effectiveness for the project. 

RESPONSE: Please see our earlier response to the scaled down monitoring comments and the cost-effectiveness issue that also apply here.

Deliverable 2 is the experimental enclosure experiments. Although interesting, the need for enclosure experiments (Deliverable 2) is uncertain. The central question this proposal addresses is whether the kokanee population will respond positively to nutrient additions and the enclosure experiments will shed little light on this question. Reviewers are not convinced of the need for this task, suggesting it is redundant with work done elsewhere.

RESPONSE: Please see our earlier response to questions about the enclosure study.