Response requested comment:

This long-running lamprey recovery and conservation project has helped to restore lamprey to the Umatilla and Grande Ronde subbasins by translocating adults and improving passage for adults and juveniles. These efforts appear to have substantially increased the distribution and abundance of juvenile lamprey. Introductions of hatchery juveniles into the Walla Walla and Tucannon subbasins are also planned. The project is credited with developing methods that are now used elsewhere in the Basin to improve artificial propagation and passage for lamprey. Project personnel are participating in regional planning committees and have helped develop documents that are being used to guide lamprey research and recovery efforts throughout the Basin.

To complete our review, however, we request that the proponents:

1.      Clarify each of the six major objectives for 2020-2024 by adding quantitative detail and timelines.

2.      Describe the adaptive management process (i.e., review cycles) by which decisions to alter course are being made.

3.      Provide information on how monitoring data will be used to assess progress toward restoration.

Comment:

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

The proposal clearly explains why this project was initiated and how it addresses biological objectives identified in the Pacific Lamprey Restoration Initiative and other agreements, as well as critical uncertainties identified in the Fish and Wildlife Program. The primary goal is to restore Pacific lamprey to self-sustaining and harvestable levels in the Umatilla, Walla Walla, Grande Ronde, and Tucannon subbasins. In 1994, when the project began, Pacific lamprey were at risk of being extirpated from the ceded lands of the CTUIR. Additionally, little was known about the biology of Pacific lamprey or about the many factors constraining their abundance. Work being performed by the project addresses all four major themes in the Council's Fish and Wildlife Program.

The proposal includes six general objectives which lack quantitative elements that could be used to measure progress. (We also note an apparent inconsistency in the Executive Summary which mentions eight "future objectives"). Anticipated benefits to lamprey recovery are not described quantitatively. Twenty-six deliverables are clearly linked to the six objectives, but only a few of the deliverables include quantitative details. Most deliverables are expected annually from 2020 to 2024. Deliverable #21 appears to be misnamed; its current descriptor suggests that genetic samples will be obtained from the hatchery lamprey being released into nature. Yet, the true objective of this task is to mark/tag a portion of these fish using non-genetic methods. A desired tagging/marking rate should be indicated.

2. Results and Adaptive Management

The latest Annual Report provides extensive summaries of activities and cumulative progress from 1995 to 2014, and a table in the proposal provides a summary of annual accomplishments to 2018. The project has contributed to Pacific lamprey conservation and recovery plans through successful collaboration with other tribal, federal, and state agencies. Notable examples include the 2017 Synthesis Report (CRITFC 2017a), which was reviewed favorably by the ISRP (ISRP 2018-02), and the 2018 Pacific Lamprey Supplementation Master Plan Step Review, also reviewed favorably by the ISRP at step 2 (ISRP-2018-05).

Adult translocation efforts associated with this project have increased juvenile Pacific lamprey abundance in the Umatilla subbasin. Moreover, pheromones from these juveniles appear to have attracted a steadily increasing number of adults into the Umatilla subbasin. Genetic samples were collected from all translocated adults to determine if progeny are returning to spawn in the Umatilla subbasin. Adult lamprey were also equipped with radio telemetry tags to identify and mitigate barriers to lamprey passage.

The project provides new knowledge on methodological issues and status and trends that are broadly applicable to Pacific lamprey populations throughout the Columbia Basin. For example, the proponents are credited with developing a method for PIT-tagging juvenile lamprey that is used throughout the Basin to provide insights about juvenile movements and passage success. The proponents are now (1) using acoustic tags in juvenile lamprey to increase knowledge of the threats during downstream migration and (2) investigating the use of eDNA to assess lamprey distribution.

The Adaptive Management section of the proposal includes good examples of lessons that have shifted the focus of the project moving forward. For example, the proposal mentions that the project has evolved from mostly research to mostly applied restoration and monitoring. However, neither the proposal nor the annual report describes the process (i.e., review cycles) by which such decisions to alter course are being made. A description of the process for adaptive management, and examples of how the project has used it to modify recovery actions and monitoring would be useful.

Annual reporting is behind schedule—the most recent annual report is for 2013-14. However, that report is well written and provides detailed information on objectives, methods, and results, as well as a discussion of cumulative results to date. Some project results have been published in the peer-review literature, presented at conferences and to the Council, and shared through public education and outreach.

3. Methods: Project Relationships, Work Types, and Deliverables

The proposal provides a good overview of activities and methods, and the 2013-14 annual report provides sufficient detail for a rigorous review of methods. Methods seem appropriate and both reports use the published literature to justify assertions and support procedures.

This project aims to serve a long-term monitoring and assessment function. The proposal and 2013-14 Annual Report together provide appropriate detail about the types of monitoring activities that have been conducted or planned. However, it is not clear how the monitoring data are being used to assess progress toward restoration. Research has been an important component of this project, but hypothesis testing is not described.

The proposal would be strengthened by including additional information on how juvenile abundance and distribution data will be estimated. The current description is limited to determining larval abundance at individual sampling sites. The proposal should also describe the procedures that will be used to choose the number and location of juvenile lamprey index sites, as well as the criteria that will be used to identify adult and juvenile passage problems. More details are also needed on the methods that will be used to transfer and release hatchery larvae into the Walla Walla and Tucannon subbasins.

Qualification: The ISRP concurs with the proponents that a synthesis of results to date should be prepared. The ISRP suggests that the synthesis should not be simply a summary of past work but rather should focus on general conclusions that can be drawn from the body of the work since initiation of the project, with supporting evidence, and possible future directions for the work. The proponents should also provide a candid assessment of status and trends in fish and habitat performances including whether trends suggest improvements in these performances related to restoration and enhancement efforts. The synthesis should describe what has been learned that could be applied to a program-wide design for lamprey restoration and research. The ISRP suggests that the synthesis be completed within one to two years. The ISRP looks forward to reviewing the synthesis.

We appreciate the proponent's willingness to provide a major synthesis of results of the project. This project is one of the longest running and most comprehensive lamprey projects in the Basin and has much interesting and useful information to provide managers and the scientific community.

Most of the ISRP's questions and comments were addressed adequately by the proponents. The proponents referred the ISRP to publications and reports in response to some individual ISRP questions or comments. Due to the time constraints imposed on the ISRP in their initial review of proposals and in review of responses, we were unable to carefully examine the reports and publications.

The proponents indicated that the Columbia Basin Lamprey Technical Workgroup is concerned about the problem of ocean impacts on survival but is in need of direction about how to address it. The proponents have been involved in the Technical Workgroup discussions.

Regarding contaminants, samples of adults and juveniles were provided to CRITFC for their lamprey contaminant study. Commenting on this study, the proponents stated that the ISRP has not provided a "Qualified" review to CRITFC's Project and therefore funding is being withheld to complete this objective." It is not clear what this response means.

The proponents provided an adequate response to the ISRP's second comment concerning the need for a long term strategy for resolving the issue of mainstem dam passage. Serious concern for this issue is evident. The proponents have been cooperating with tribes and the Corps of Engineers in developing a plan of action for improved passage. They described the multiple efforts currently being undertaken to improve lamprey passage at mainstem dams. Considerable information was made available regarding the relatively low passage rates at the various dams.

The ISRP commented concerning mainstem dam passage: "Even if reproduction is successful, however, adult returns could be seriously impaired by passage problems at mainstem dams. The proponents should discuss how long outplanting of adults will continue before success or failure of the program is determined and give their perspective on the time frame for overcoming mainstem dam passage problems." The point was whether mainstem dam problems can be resolved on a timeframe to allow the restoration work on the tributaries to be effective? The proponent's response – "The ISRP should review the Corps 10-year lamprey passage plan to increase their awareness of this plan" – is insufficient to address this important issue.

Based on the information presented in the proposal, the ISRP deemed the work proposed in Objective 4, "Develop structures to improve adult lamprey passage success," not scientifically justified because better understanding of passage under different flow and temperature conditions and prioritization of passage barriers in the Umatilla according to passage efficiency was needed before investment in passage improvement structures throughout the Umatilla was undertaken. In their response, the proponents provided detailed information to justify that diversion screens pose a serious problem for lamprey passage in the Umatilla and installation of passage improvement structures can be implemented. The ISRP now considers this objective to be scientifically justified.

For Objective 6, "Estimate the numbers of juvenile lampreys migrating out of the Umatilla River," the ISRP commented: "The method for estimating outmigrant production needs to be explained more clearly and in more detail." Although more detail was provided, the proponents did not discuss problems with enumerating lampreys identified in other lamprey projects (screw trap inefficiency/retainment issues).

The ISRP considered Objective 7 in the initial proposal, "Investigate juvenile lamprey screening criteria for use in the Umatilla Subbasin," which proposed a series of laboratory and field experiments to determine the effects of diversion screens on juvenile lamprey scientifically unjustified due to lack of detail about the experimental design and methods. Details of the study design and methods were provided in the response. The proponents documented problems with effects of dewatering on lamprey as well as the ineffectiveness of screens. The ISRP now considers this objective scientifically justifiable. The work could be of great value in reducing lamprey mortality at irrigation diversion screens.

The ISRP requests a response on following five primary items (some additional questions are asked in the “Other ISRP comments” below): 1. Ocean survival and contaminant aspects. As explained in ISAB 2009-3, there is strong evidence of a coast-wide pattern in lamprey survival, suggesting a marine/estuarine influence on this anadromous species. In addition, as also explained in ISAB 2009-3, lamprey are high in lipids and contaminants that likely bioaccumulate in this species with possible effects on survival. The proponents need to address these issues. 2. An explanation of the long term strategy for resolving the issue of mainstem dam passage problems is needed. Even if translocations work, the translocated animals’ progeny may not survive passage over mainstem dams. The proponents’ entire program is contingent on either resolving the problem or continuing translocation on a long term basis. If translocation is to be continued then it needs to be justified on a cultural-economic basis that does not use scientific criteria. 3. Objectives 1, 2, 3, 5, and 6 could be scientifically justified if the proponents provide a satisfactory response to ISRP questions. Objectives 4 and 7, in their current form, are not justifiable at this time for reasons described below. 4. The proponents need to provide a synthesis of results directly related to the proposed work – in particular, results related to evaluation of translocation of adults including larval densities before as well as after outplanting began (by larval size/age class, if possible), outmigrant numbers before and after translocation, and redd densities if available. ISRP questions related to methods and metrics for each objective need to be addressed. In general, more details about the study designs are needed to determine whether the studies, as conceived, will adequately answer the questions being posed. 5. Within a year the proponents should prepare a major synthesis of project accomplishments for review by the ISRP. The synthesis should include objectives, methods, results, data analyses and interpretation, major conclusions that can be drawn from the work to this point, and future directions of the work. The proponents need to present a comprehensive plan for assessing the success of adult translocation. The proponents would be wise to enlist the services of a statistician in analyzing their data. The proposal presents a comprehensive multidimensional plan for monitoring and evaluating lamprey recovery in the Umatilla Basin. A great deal of useful information concerning lamprey abundance and distribution and factors limiting productivity is being gathered. Adequate response to the questions posed above should reinforce the soundness of the science underlying this worthwhile project. Other ISRP comments: 1. Purpose, Significance to Regional Programs, Technical Background, and Objectives The decline of Pacific lamprey in the Columbia River Basin and the need for restoration is largely unquestioned at this point in time. This project is one of several lamprey projects in the Columbia Basin. It was designed to provide critical information to restore Pacific lamprey in the Umatilla River. The project addresses five of the 16 aquatic biological objectives listed in the Umatilla Subbasin Plan, provisions of the 2000 Fish and Wildlife Program, critical uncertainties defined by the Columbia River Basin Lamprey Technical Workgroup, and needs identified in the Tribal Lamprey Restoration Plan developed by CRITFC tribes. The results from this project will be useful in other subbasins. The objectives are most clearly stated in the Study Design section of the proposal. The Deliverables are essentially the same as these objectives. They include 1) increase larval abundance in the Umatilla River by continuing to outplant adult lamprey, 2) estimate the numbers of adult lampreys entering the Umatilla River, 3) monitor passage success to spawning areas, 4) develop structures to improve adult lamprey passage success, 5) monitor larval population trends in the Umatilla River by conducting electrofishing surveys, 6) estimate the numbers of juvenile lampreys migrating out of the Umatilla River, and 7) investigate juvenile lamprey screening criteria for use in the Umatilla Subbasin. This set of objectives defines a comprehensive plan for monitoring lamprey populations in the Umatilla River. Objectives 1, 2, 3, 5, and 6 could be scientifically justified if an adequate response to ISRP questions is provided by the proponents. Objectives 4 and 7 currently are not justified for the reasons given below. 2. History: Accomplishments, Results, and Adaptive Management The project appears to have accomplished a great deal, but results were only briefly summarized (in a few sentences) for each year of the project. The proponents instead refer the reviewer to a 20-page paper in an American Fisheries Society symposium (Close et al. 2008) and Moser (2005) for a description of passage improvements. The proponents should have summarized concisely the significant results of the project, especially those directly related to this proposal, with supporting data and analyses, rather than referencing a symposium paper. For example, even a brief explanation of how the low elevation ramp works on the smaller dams would be helpful. Of particular use in reviewing this proposal would have been a more detailed presentation of results related to adult outplanting including larval densities before as well as after outplanting began (by larval size/age class, if possible), outmigrant numbers before and after translocation began, and redd densities if available. The CRITFC lamprey plan is mentioned in passing. It would be helpful to know if it is now finalized. The proponents say little about adaptive management except to note that they reduced the number of adult lamprey taken at Bonneville Dam for supplementation in the Umatilla due to low adult returns. 3. Project Relationships, Emerging Limiting Factors, and Tailored Questions for Type of Work (Hatchery, RME, Tagging) This project is one of several lamprey restoration projects being conducted in the Columbia Basin. Two salmon monitoring and evaluation projects on the Umatilla River assist in capturing larval lamprey. Project #198902700 (Power Repay Umatilla Basin Project) is seeking to include flow enhancement to aid upstream passage for Pacific lamprey. This project will coordinate with other radio telemetry programs in the region to utilize existing radio telemetry arrays in the area to track lamprey movement. The proponents correctly stated that findings in this study will have application in nearly every subbasin. The proponents state that they are unaware of emerging limiting factors for lamprey largely because little information is available on effects of emerging factors such as climate change on lamprey, although clearly reduced stream flow and elevated water temperature, both potential impacts of climate change, will affect lamprey. Chemical contaminants need to be considered as an emerging limiting factor. Lamprey have a high lipid content and so can accumulate many contaminants. It seems that lamprey projects could have an Oregon Department of Environmental Quality or EPA cooperator, and, when samples are collected (the greatest cost often is in collecting the samples), some analyses could be performed to address the contaminant issue. This could be especially important in waters near wastewater treatment plants (personal care products, pharmaceuticals, and flame retardants) or intensive agriculture areas (pesticides). These problems may be especially critical where the rivers/streams are small with low flow (lack of dilution). As explained in detail in ISAB 2009-3 and several recent ISRP reviews of other lamprey proposals a more holistic approach to lamprey restoration is required, with particular attention to marine/estuarine habitat as a limiting factor. Nevertheless, adult passage at mainstem dams and low level dams in tributaries is acknowledged as a major issue to be resolved. 4. Deliverables, Work Elements, Metrics, and Methods Many of the methods seem relatively standard and the concepts seem very logical. The project, however, needs a statistician to assist with data analysis, especially the tagging effort. It seems very late in the project’s life to have this need, especially for adequately designing studies. The big question is “Will the project answer some of the critical questions, or is it just collecting data?” The following are comments on individual objectives: Objective 1: Increase larval abundance in the Umatilla River by continuing to outplant adult lamprey. The Umatilla is the test case within the Columbia Basin for translocation of adult lamprey. Adults are collected at Bonneville Dam or Willamette Falls and released into the Umatilla River. Translocation of adults began in 2000. Larval lamprey densities after translocation began are considerably higher than prior to outplanting of adults, suggesting that successful reproduction of translocated adults had occurred. The hope is that translocating adult lamprey will result in a self-sustaining population in the Umatilla Subbasin. Even if reproduction is successful, however, adult returns could be seriously impaired by passage problems at mainstem dams. The proponents should discuss how long outplanting of adults will continue before success or failure of the program is determined and give their perspective on the time frame for overcoming mainstem dam passage problems. An escapement goal should be provided, and the proponents should discuss how it was determined. The ISRP understands that setting such a goal could be difficult given the lack of information on historical lamprey run sizes but an escapement target, even if it is tentative, would help track success of the program. Objective 2: Estimate the numbers of adult lampreys entering the Umatilla River. The proposal could be improved if discussion of the mark-recapture methodology were expanded. More detail about application of the Schaefer method is needed including why it was chosen over other methods. How will the assumptions of the Schaefer method be addressed? How will the fish be marked? Will there be secondary marks? Will tag retention rates be calculated and how? It may be helpful for the proponents to review the discussion of the mark-recapture methodology provided in the proposal for Project 2002-016-00, “Evaluate the Status of Pacific Lamprey in the Lower Deschutes River.” Variance estimates for populations sizes need to be within acceptable standards. Objective 3: Monitor passage success to spawning areas. This is an important objective and needs more detailed explanation. Will groups be tagged and released throughout the summer to determine migration patterns at different water temperatures and stream flows? Will fish be released below each dam within the system or will groups released below downriver dams be followed progressively through upriver dams, or both? If so, how many fish will be tagged? How will passage efficiency be related to water temperature and river flow? Statistical analysis of the data needs to be better explained. Objective 4: Develop structures to improve adult lamprey passage success. This objective pertains to designing and installing lamprey adult passage structures at irrigation diversions and is not scientifically justified at this time. Radiotelemetry work performed to date by the proponents, although preliminary, indicates that lamprey adult may have difficulty passing low head dams such as irrigation diversion dams. More work is needed, however, to better understand adult upstream passage under different flow and temperature conditions and to prioritize passage barriers according to passage efficiency before investment in passage improvement structures throughout the basin is warranted (this work is proposed in Objective 3). In the initial radiotelemetry study, sample sizes of adult lamprey were small, few fish passed upstream of Boyd Dam located on the lower river and so passage problems posed by upriver dams are not well understood, and passage seemed to be strongly affected by water temperature and stream flow. Also, more information about the passage structures, their design, and effectiveness needs to be given. Perhaps evaluating the effectiveness of passage structures at a few dams should be undertaken before a large scale installation is begun. Objective 5: Monitor larval population trends in the Umatilla River by conducting electrofishing surveys. The proponents indicate that they will “relocate larval density index sites” (Task 5.1). They refer to 33 index sites where larval estimates were obtained prior to adult outplanting. Are these the sites to be relocated and, if so, why are they being relocated and how will new sites be chosen? How will population sizes be estimated “through statistical analysis?” Will habitat variables be measured and related to abundance and distribution? If so, what will be measured and how will the analysis be done? What is the Zippen formula and why was it chosen to calculate larval density? The sponsors state under Background, “Where initial surveys in 1998 provided evidence that larval lamprey were not present in the system, after five years of supplementation efforts, we find that larval lampreys are persisting at all upper index sites (Figure 3), providing evidence that habitat may not be the limiting factor for successful recruitment.” If this is the case can juvenile habitat restoration be justified? Discussion of the statistical methods for estimating juvenile lamprey densities would improve the proposal. Technical problems associated with lamprey trapping such as lamprey escaping from rotary trap boxes are not mentioned. Objective 6: Estimate the numbers of juvenile lampreys migrating out of the Umatilla River The method for estimating outmigrant production needs to be explained more clearly and in more detail. Objective 7: Investigate juvenile lamprey screening criteria for use in the Umatilla Subbasin Objective 7 pertains to laboratory and field studies on impacts of irrigation diversion screens on larval lamprey and is not scientifically justified at this time. Before undertaking an extensive laboratory and field study, the proponents should conduct a preliminary study in the field to assess the relative magnitude of entrainment, injury, and mortality of juvenile lampreys and determine how serious a problem diversion screens present. This information could be used to justify a laboratory and more extensive field study. Objectives, research design, and methods for the USGS laboratory and field studies presented in the current proposal are insufficiently detailed to meet scientific criteria. Deliverable 8: Publish results of Pacific lamprey studies. This appears to be a worthwhile effort, but no details are given on exactly what would be published.

The ISRP has previously called attention to the need for oversight of work on lamprey in the Columbia Basin. There has been an effort in this direction (apparently through the Columbia Basin Fish and Wildlife Authority) by appointment of a Columbia Basin Lamprey Technical Working Group. However, it is clear that the Technical Working Group has served as a medium of information exchange, rather than as a coordinating body to assign tasks and avoid unnecessary duplication of effort, as was intended by the ISRP recommendation. The sponsors are reluctant to accept the concept of a "generic" applied study on lamprey on their watershed (or somewhere else in the Basin) that might provide results that are widely applicable. Watershed-specific issues, such as identification of specific obstacles to passage, are no doubt important but a concerted, well-coordinated, and cooperative effort would provide better scientific results with respect to identification of physical and biological characteristics of impediments to passage. The basic question is "Does the region need a lamprey project with similar goals, objectives and tasks in every subbasin?" If this criterion is applied to the Umatilla Basin, the question becomes "What is the innovative work that is being done that is expected to be applicable basinwide, or that requires tasks specific to the Umatilla?"

The ISRP had asked for a revision of the Project History section, organized by objectives. This was not supplied. We remain convinced that the sponsors themselves would benefit from a progress report that would relate the particular aspects of the life history and behavior of lamprey in the Umatilla River.

The sponsors agree with the ISRP that if mainstem passage is not improved, major increases in adult abundance in the Umatilla River may not occur. The question to be addressed by this proposal then is, to what degree factors within the Umatilla Basin might still limit abundance even if mainstem passage is improved. Direction for efforts of this project would be improved by identification of potential or possible limiting factors in the Umatilla Basin, and a focus on those that are determined to be likely to have the greatest effect on abundance. It is difficult to reconcile the sponsor's statement, made later in their response, that habitat is not a limiting factor for lamprey in the Umatilla River with comments such as: "The issue of dewatering is serious and the low head diversion dams that provide the water may also inhibit migration."

The Abstract of this proposal provides a useful summary of objectives for work in the Umatilla River: "In addition to increasing the abundance of larval lamprey in the subbasin, key components are to establish that more adult lamprey are returning to the Umatilla Subbasin, and that they are able to reach historical spawning areas. Consequently, the project objectives are: (1) estimate the numbers of adult lampreys entering the Umatilla Subbasin; (2) investigate the olfactory cues lamprey use to orient in the Umatilla Subbasin; (3) monitor passage success to spawning areas; (4) develop structures to improve passage success; (5) increase larval abundance in the Umatilla River by continuing to outplant adult lamprey; (6) monitor larval population trends in the Umatilla River by conducting electrofishing surveys, and (7) estimate the numbers of juvenile lampreys migrating out of the Umatilla River."

ISRP requested information on annual reports and meta-data. The sponsors did not respond adequately to this request. They refer to reports with results but do not summarize or give citations to many of the reports.

The ISRP concludes that benefits in terms of potential for improved abundance of Pacific lamprey in the Umatilla Basin are likely to accrue from portions of this project, modified according to the following recommendation.

Fundable in part, as listed below:

Objectives 1, 3, 4 (except Task 2d), 5, and 6. Emphasis of the work should be placed on:

1. Enumeration of upstream migration of adults in the Umatilla River. The proposed radio tracking approach deserves more emphasis. Sponsors should obtain advice from a statistician in the design and analysis of their enumeration efforts.

2. Identification of barriers to adult migration within the river. The sponsors should determine particular features of these barriers that inhibit or prevent passage and consider the possibility that if mainstem passage is the principle cause of low adult abundances, then improvements in the migration corridor in the Umatilla Basin may have little impact on adult returns.

3. Outmigrant abundance must be accurately determined. With the low numbers expected, increased effort will be required beyond what is described in the proposal, with a rigorous statistical design applied to the sampling of juveniles, with the assistance of a statistician.

4. Quantify effects of river operations, i.e., pumping of water from the Columbia River and its subsequent distribution, on abundance and success of passage of lamprey upstream and downstream. (Quantify with river flow and lamprey counts.) (Note the ISRP comments on other proposals for work in the Umatilla River, specifically 198343600, in which we recommend incorporation of all projects into a package we refer to as the Umatilla Initiative, which should be established to evaluate the effects on fish abundance of restoration of flows in the river, other habitat improvement measures, and the hatchery. Restoration of flow would seem to be an obvious habitat improvement measure that ought to affect abundance of lamprey.)

5. Carefully investigate the causes for low larval survival. Likely suspects include fluctuations or reductions in flow brought about by irrigation removals or other operations, leading to stranding and compaction of substrate in which lamprey are located. Investigate possibilities for modification of operations, if warranted.

Not Fundable:

We view objective 2 as being unlikely to reveal measures that might lead to increases in lamprey abundance. Our conclusion is that further studies of stress steroids, larval extracts, sex pheromones, bile salts, synthetic compounds or the like, are not, at this time, fruitful areas of pursuit and are not likely to suggest measures that might lead to increases in lamprey abundance. This work cannot be justified given current knowledge (or the lack of it) of up-river lamprey populations.