Barrier Dams Research Articles

Risk Assessment and Treatment Countermeasures for the Barrier Lakes of Wenchuan Earthquake on May 12th, 2008

Abstract:This paper introduced the first hand investigation results of the risk and treatment measures for the barrier lakes triggered by the earthquake of Wenchuan. Characteristics of 10 barrier lakes were investigated and analyzed; procedure and methods for barrier lake treatment were brought forward. The dams of the barrier lakes can be classified as two classes: block rock in the south and loose deposit in the north. All the barrier dams were stable at the time of investigation, but water drainage channel needed to be constructed and to be protected from blockage or collapse. After the rain season of 2008, some dams needed to be consolidated, and change the barrier lakes to reservoirs.

Over the Falls? Rapid Evolution of Ecotypic Differentiation in Steelhead/Rainbow Trout (Oncorhynchus mykiss)

Adaptation to novel habitats and phenotypic plasticity can be counteracting forces in evolution, but both are key characteristics of the life history of steelhead/rainbow trout (Oncorhynchus mykiss). Anadromous steelhead reproduce in freshwater river systems and small coastal streams but grow and mature in the ocean. Resident rainbow trout, either sympatric with steelhead or isolated above barrier dams or waterfalls, represent an alternative life-history form that lives entirely in freshwater. We analyzed population genetic data from 1486 anadromous and resident O. mykiss from a small stream in coastal California with multiple barrier waterfalls. Based on data from 18 highly variable microsatellite loci (He = 0.68), we conclude that the resident population above one barrier, Big Creek Falls, is the result of a recent anthropogenic introduction from the anadromous population of O. mykiss below the falls. Furthermore, fish from this above-barrier population occasionally descend over the falls and have established a genetically differentiated below-barrier subpopulation at the base of the falls, which appears to remain reproductively isolated from their now-sympatric anadromous ancestors. These results support a hypothesis of rapid evolution of a purely resident life history in the above-barrier population in response to strong selection against downstream movement.

Factors Responsible for the Reduction in Quantity of the Lampricide, TFM, Applied Annually in Streams Tributary to the Great Lakes from 1979 to 1999

Integrated management of sea lampreys ( Petromyzon marinus) in the Great Lakes relies primarily on the application of the lampricide, 3-trifluoromethyl-4-nitrophenol (TFM), into streams to eradicate larval populations. From 1979 to 1999, 1,282 lampricide treatments were conducted on 316 streams. During the period from 1979 to 1989, an average of 52,904 kg active ingredient (kg/yr) of TFM was applied annually. This was reduced to an average of 38,698 kg/yr for the decade of 1990 to 1999. This reduction was enhanced in the years of 1995 to 1999 to an average of 34,120 kg/yr, a 36% reduction from that used in 1979 to 1989. Efforts to minimize non-target mortality and to reduce applications of pesticides into the environment were the impetus for this reduction. The three factors that influenced annual TFM use were number of streams treated and conditions during treatment, the adaptation of several management techniques to reduce TFM use, and alternative control techniques. Changes in streams selected for treatment and scheduling treatments during low stream discharge accounted for about 26% of the reduction in annual TFM use. The management techniques include lampricide treatments with a TFM/niclosamide mixture, pH/alkalinity prediction models to determine minimum TFM requirements, maintaining lampricide concentrations at or near minimum levels, computer modeled treatment planning, and single block treatments, and were responsible for about 70% of the reduction observed in the 1990s. Alternative control techniques (barrier dams) accounted for only 4% of the reduction.

Low-Head Barrier Dams Restrict the Movements of Fishes in Two Lake Ontario Streams

The Great Lakes Fishery Commission (GLFC) is considering greater use of low-head barrier dams on stream tributaries of the Laurentian Great Lakes to control populations of sea lampreys Petromyzon marinus. The impact of these barriers on nontarget fishes is not known. A mark–recapture study on four Lake Ontario streams examined movements of fishes in streams with (barrier) and without (reference) low-head barriers. A significantly lower proportion of fishes moved across a real barrier on barrier streams than across a hypothetical barrier on reference streams (0.15 versus 0.50, respectively). The impact of the barriers on movement was more pronounced in spring and fall than in summer. However, the likelihood of fishes moving versus not moving between sample segments on either side of a barrier location (but not across the barrier) did not differ significantly between barrier and reference streams. The upstream (longitudinal) decline in species richness was greater for barrier streams than for reference streams in each season. At both interspecific and intraspecific levels, mean total lengths of fish traversing real barriers were significantly greater than the mean total lengths of fish traversing hypothetical barriers. Our findings demonstrate that low-head barriers restrict the movements of some fishes and suggest this restriction affects assemblage structure above the barrier.

Lake Trout (Salvelinus namaycush) Populations in Lake Superior and Their Restoration in 1959–1993

Naturally-reproducing populations of lake trout (Salvelinus namaycush) have been reestablished in most of Lake Superior, but have not been restored to 1929-1943 average abundance. Progress toward lake trout restoration in Lake Superior is described, management actions are reviewed, and the effectiveness of those actions is evaluated; especially stocking lake trout as a tool for building spawning stocks, and subsequently, populations of wild recruits. Widespread destruction of lake trout stocks in the 1950s due to an intense fishery and sea lamprey (Petromyzon marinus) predation resulted in lower overall phenotypic diversity than was previously present. Stocking of yearling lake trout, begun in the 1950s, produced high densities of spawners that reproduced wherever inshore spawning habitat was widespread. Sea lampreys were greatly reduced, beginning in 1961, using selective chemical toxicants and barrier dams, but continue to exert substantial mortality. Fishery regulation was least effective in Wisconsin, where excessive gillnet effort caused high by-catch of lake trout until 1991, and in eastern Michigan, where lake trout restoration was deferred in favor of a tribal fishery for lake whitefish (Coregonus clupeaformis) in 1985. Restoration of stocks was quicker in offshore areas where remnant wild lake trout survived and fishing intensity was low, and was slower in inshore areas where stocked lake trout reproduced successfully and fishing intensity was high. Inshore stocks of wild lake trout are currently about 61 % of historic abundance in Michigan and 53% in Wisconsin. Direct comparison of modern and historic abundances of inshore lake trout stocks in Minnesota and Ontario is impossible due to lack of historic stock assessment data. Stocks in Minnesota are less abundant at present than in Michigan or Wisconsin, and stocks in Ontario are similar to those in Michigan. Further progress in stock recovery can only be achieved if sea lampreys are depressed and if fisheries are constrained further than at present.

Consumption of benthic invertebrates by waterbirds in the Oosterschelde estuary, SW Netherlands

The number of waders in the Oosterschelde, S.W. Netherlands, declined after a reduction in intertidal area due to the construction of a storm surge barrier and secondary dams, suggesting that the carrying capacity had been reached (Schekkerman et al., 1993). In this paper we present data on consumption and predation pressure by birds to explore whether the reduction in their numbers is due to prey depletion or to other factors.

Sea Lamprey (Petromyzon marinus) Control — Where to From Here? Report of the SLIS Control Theory Task Force

Sea lamprey (Petromyzon marinus) control with selective toxicants has reduced sea lamprey abundance in the Great Lakes to levels which permit survival of desirable fish species, but development of alternate and supplemental control methods is essential since chemicals cannot be used indefinitely. The Task Force addressed hypotheses which relate to regulation of sea lamprey numbers during different life history stages and why sea lampreys appear to affect fish stocks differently in various bodies of water. Examination of the information about the various factors that control sea lamprey abundance, both natural and man-made, permitted the Task Force to develop several hypotheses and to indicate areas where additional emphasis or research could produce new or supplementary control methods. Efforts to develop an integrated program of sea lamprey control should be accelerated by development of present promising areas as well as expansion in new directions. Sea lampreys when compared with teleosts exhibit many features of a prototype vertebrate and some unique specializations. Physiological, biochemical, or behavioral differences between lampreys and teleosts may be exploitable for developing control techniques specific to sea lampreys.Key words: sea lamprey, Great Lakes, population control, barrier dams, integrated pest management, buffer species, physiology, teleosts

Role of Physical Barriers in the Control of Sea Lamprey (Petromyzon marinus)

Mechanical and electromechanical barriers played a significant role in the initial attempts to control sea lamprey (Petromyzon marinus) populations in the upper Great Lakes. More recently electromechanical weirs have been used to assess the relative abundance of spawning-run sea lampreys in Lake Superior. Development of an integrated control approach to sea lamprey control has stimulated an ongoing research program to define structural and/or velocity criteria that can be used to design barrier dams that block spawning runs of sea lamprey.Key words: sea lamprey, Petromyzon marinus; physical barriers, burst swimming speed, barrier dam criteria

Sea Lamprey (Petromyzon marinus) in Lakes Huron, Michigan, and Superior: History of Invasion and Control, 1936–78

Sea lamprey (Petromyzon marinus) entered the upper three Great Lakes in the late 1930s and began making sharp inroads into the fish stocks by the mid-1940s in lakes Huron and Michigan and the mid-1950s in Lake Superior. The first serious attempts to control the parasite began in 1950 with the installation of mechanical barriers along the United States shore of Lake Huron to block spawning runs. Electrical barriers, developed in 1952, were installed in 132 tributaries of the Great Lakes by 1960, but control measures did not become effective until after 1958, when a selective toxicant — the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) — was used to destroy larval lampreys in streams. In the 21 years, 1958–78, 1223 treatments of tributaries of the upper three lakes with TFM were completed in 334 streams — 91 in Canada and 243 in the United States. Evidence of the success of the control program was soon obvious: first by reduced sea lamprey spawning runs as measured by the numbers of adults taken at electrical barriers; second by significant decreases in the incidence of sea lamprey wounds on lake trout (Salvelinus namaycush); and finally by the excellent responses of major fish stocks to sea lamprey control. All three of the upper lakes have large numbers of lake trout, coho salmon (Oncorhynchus kisutch), chinook salmon (O. tshawytscha), and other salmonids available to the sport fishery and in some areas to the commercial fishing industry. Although the sea lamprey control program has been successful, it is important that emphasis be placed on developing new and innovative methods to reduce the dependence on lampricides. It is expected that a fully integrated program will eventually comprise several methods, including permanent barrier dams on selected streams and the use of sterilants, attractants, repellents, and biological controls, as well as chemical lampricides.Key words: sea lamprey, distribution, abundance, history, predation, integrated controls, Huron, Michigan, Superior