Balancing Fisheries Management and Water Uses for Impounded River Systems

2008 ◽  
Keyword(s):  
Plant Community ◽  
Grass Carp ◽  
Aquatic Plant ◽  
Aquatic Vegetation ◽  
Fish Habitat ◽  
Hydrilla Verticillata ◽  
Management Plan ◽  
Ctenopharyngodon Idella ◽  
Herbicide Treatments ◽  
Stated Time

<em>Abstract</em>.—Lake Conroe has long been synonymous with the controversy surrounding control of the exotic plant hydrilla <em>Hydrilla verticillata</em>. By the time hydrilla was first identified in Lake Conroe in 1975 (2 years after impoundment), the plant covered 470 acres. By 1979, hydrilla increased to 4,500 acres and was causing problems for boaters, skiers, and swimmers. As a result of efforts by the Lake Conroe Association and its supporters and despite objections by Texas Parks and Wildlife Department (TPWD) staff, the Texas Legislature directed the Texas Agricultural Experiment Station and TPWD to conduct a study to determine the ability of grass carp <em>Ctenopharyngodon idella </em>to control hydrilla and the effects of hydrilla removal on fish populations, the fishery, and the limnology of the reservoir. Between September 1981 and September 1982, 270,000 diploid grass carp were released into Lake Conroe. By October 1983 hydrilla and all other aquatic vegetation had disappeared from the reservoir. Hydrilla growth was suppressed in Lake Conroe for the next 13 years; however, in 1996, approximately 3 acres of hydrilla were discovered. For the next 8 years (1997–2004), herbicide treatments funded primarily by the San Jacinto River Authority (SJRA) and conducted by SJRA and TPWD successfully limited hydrilla expansion. At the same time, native vegetation establishment by TPWD, U.S. Army Engineer Environmental Research and Development Center’s Lewisville Aquatic Ecosystem Research Facility, and several angling groups led to diversification and expansion of the native aquatic plant community in Lake Conroe and provided an alternative to a monoculture of hydrilla for fish habitat. However, by 2005, herbicide treatments alone were unable to control hydrilla expansion. As a result, TPWD and SJRA determined the need to develop a comprehensive hydrilla management plan for Lake Conroe. Therefore, a plan based on the principles of Integrated Pest Management was developed with the cooperation of angler organizations, property owner associations, local businesses, and other user groups. The plan integrated use of ecological, biological, chemical, and mechanical strategies for control of hydrilla while promoting diversity of the aquatic plant community. The stated time line of the plan was to reduce the surface coverage of hydrilla at Lake Conroe to less than 40 acres by spring of 2008, while preserving a diverse aquatic plant community.

scholarly journals Combate biológico de Hydrilla verticillata Vahl con carpa herbívora (Ctenopharyngodon idella Vía).

2016 ◽  
Vol 7 (2) ◽  
pp. 1
Author(s):  
Manuel Rojas ◽  
Renán Agüero A.
Keyword(s):  
Costa Rica ◽  
Equilibrium Point ◽  
Water Flow ◽  
Grass Carp ◽  
Hydrilla Verticillata ◽  
Production Costs ◽  
The Other ◽  
Ctenopharyngodon Idella ◽  
Aquatic Weed ◽  
The Third

Hydrilla verticillata has become an important aquatic weed of irrigation canals at some rice farms of Guanacaste, Costa Rica. This species slows water flow, often causing flooding in adjacent roads, its control increases overall production costs. To evaluate efficiency of the grass carp in controlling Hydrilla three trials were conducted, with varying densities of the fish. In the preliminary trial, 987 kg/ha of grass carp reduced Hydrilla biomass in nearly 62 m3 in 21 days. During the second trial, treatments with 1264 and 2042 kg/ha of the fish completely eliminated the weed after 30 days. However, during the third trial, 1000 kg/ha of the carp only reduced Hydrilla volume in 19 m3, after 66 days. The ratio kg of carp/initial volume of Hydrilla proved to be more important than just the kg/ha of the carp. It was observed that when such ratio was lower than 0.02, the carp did not provide a satisfactory control of Hydrilla; on the other hand, a ratio higher than 0.05 significantly reduced the weed's biomass. The equilibrium point between weed regrowth and biomass consumed by the carp occurred at a ratio close to 0.03.

scholarly journals Persistence of Triploid Grass Carp in Devils Lake, Oregon

2016 ◽  
Vol 7 (1) ◽  
pp. 153-161 ◽  
Author(s):  
Benjamin J. Clemens ◽  
John J. Spangler ◽  
Paul L. Robertson ◽  
Gary M. Galovich ◽  
Craig R. Banner ◽  
...  
Keyword(s):  
Sample Size ◽  
Grass Carp ◽  
Aquatic Vegetation ◽  
Ctenopharyngodon Idella ◽  
Catch Per Unit Effort ◽  
Multiple Measures ◽  
Devils Lake ◽  
Grass Carp Ctenopharyngodon Idella ◽  
Biological Tool ◽  
The Dead

Abstract Grass carp Ctenopharyngodon idella are sometimes used as a biological tool for managing aquatic vegetation in reservoirs. Sterile, triploid fish were stocked in Devils Lake, Oregon, during 1986, 1987, and 1993 to control aquatic vegetation. We present a case study for using multiple measures on the same fish to determine whether illegal stocking of fertile, diploid grass carp occurred. An investigation into the estimated age of a dead grass carp found in Devils Lake suggested that it was significantly younger than would otherwise be expected, given the only stocking events occurred during 1986, 1987, and 1993. To determine whether illegal stocking or reproduction by presumed sterile grass carp had occurred in Devils Lake, we conducted a study that balanced the needs of lethally sampling grass carp for biological measures with the socially and politically sensitive sentiment of the pro–grass carp citizenry of Devils Lake. These considerations, in combination with a low catch per-unit effort, resulted in a modest sample size for grass carp. We sampled grass carp and recorded multiple measures for each fish. Ploidy testing of blood samples indicated the grass carp were all triploid. Based on gonadal histopathology, six fish were male, two were female, and two were sex-indeterminate with severe gonadal dysgenesis. Age estimates from lapillus otoliths were consistent with fish originating from the legal stocking events in Devils Lake. The grass carp were 21–30 y old, and we were unable to find published reports of grass carp anywhere else in the world that are older. The grass carp were significantly smaller than much younger fish from other regions. The small size of these grass carp relative to their age in Devils Lake suggests food limitations that stunted growth. The dead grass carp that was the impetus for this study was aged by anatomical structures that we have since found to be unreliable. This suggests that the dead grass carp was probably in fact older and originated from the legal stockings. The use of multiple biological measurements on a modest sample size of grass carp, combined with the knowledge that no juvenile grass carp have been observed since legal stocking occurred, lead us to conclude that the grass carp in Devils Lake are sterile fish that originated from legal stocking events.

of control. The state of Queensland has generous expertise in this area, with the CSIRO Division of Entomology – Lands Department group in Brisbane boasting spectacular success against Salvinia and Eichhornia, and near the reservoir at James Cook University a USDA unit was involved in successes with the Tennessee Valley Authority (TVA) (see Chapter 12) using a range of stem-boring and leaf-mining insects (Balciunas et al. 1993). One might consider the herbivorous grass carp Ctenopharyngodon idella, originally from China, more as a harvester than a biological control agent. This fish grazes on submerged weeds such as Hydrilla, Myriophyllum, Chara, Potamogeton and Ceratophyllum, and at stocking rates of 75 fish/ha control is rapidly achieved. Some introductions in the USA have resulted in removal of all vegetation (Leslie et al. 1987), and in the Australian context the use of sterile (triploid) fish (Cassani and Canton 1985) could be the only consideration. However, in view of the damage already done by grass carp to some inland waterways in Australia, it is suspected that this option would be greeted with horror. Mechanical control involves the physical removal of weeds from a problem area and is useful in situations where the use of herbicides is not practical or poses risks to human health or the environment. Mobile harvesters sever, lift and carry plants to the shore. Most are intended for harvesting submerged plants, though some have been designed or adapted to harvest floating plants. Handling the harvested weed is a problem because of their enormous water content, therefore choppers are often incorporated into harvesting machinery design. However, many mechanical harvesters have a small capacity and the process of disposing of harvested plant material is time-consuming. Any material that remains may affect water quality during the decay process by depleting the water of oxygen. Furthermore, nutrients released by decay may cause algal blooms (Mitchell 1978). Another disadvantage of mechanical removal is that disturbance often promotes rapid new growth and germination of seed, and encourages the spread of weed by fragmentation. Some direct uses of macrophytes include the following: livestock food; protein extraction; manufacture of yeast; production of alcohol and other by-products; the formation of composts, mulches and fertilizers; and use for methane generation (Williams 1977). Herbicides either kill on contact, or after translocation through the plant. Some are residual and retain their toxicity for a period of time. Where herbicides are used for control of plants, some contamination of the water is inevitable (Bill 1977). The degree of contamination depends on the toxicity of the material, its fate and persistence in the water, the concentration used and the main purpose served by the water. After chemical defoliation of aquatic vegetation, the masses of decaying organic debris produced can interfere with fish production. Several factors must be taken into account when selecting and adapting herbicides for aquatic purposes, including: type of water use; toxicity of the herbicide to humans, fish, stock, and wildlife; rate of disappearance of residues, species affected and duration of control; concentration of herbicide; and cost (Bill 1977). The TVA has successfully used EPA-approved herbicides such as Endothall, Diquat, Fluridone and Komeen against Hydrilla (Burns et al. 1992), and a list of approved

1998 ◽  
pp. 153-154
Keyword(s):  
Grass Carp ◽  
Algal Blooms ◽  
Aquatic Vegetation ◽  
Protein Extraction ◽  
Biological Control Agent ◽  
Problem Area ◽  
Ctenopharyngodon Idella ◽  
Methane Generation ◽  
Tennessee Valley ◽  
Grass Carp Ctenopharyngodon Idella

BIOLOGICAL MELIORATION OF THE AZOV LIMANS OF THE KRASNODAR KRAI AND THE POSSIBILITY OF USING FUNDS OBTAINED AS COMPENSATION FOR THE HARM TO THE WATER BIOLOGICAL RESOURCES

2017 ◽  
pp. 34-41 ◽  
Author(s):  
Oleg Sergeyevich Denisenko
Keyword(s):  
Fish Species ◽  
Grass Carp ◽  
Aquatic Vegetation ◽  
Silver Carp ◽  
Environmental Data ◽  
Ctenopharyngodon Idella ◽  
Complete Disappearance ◽  
Hypophthalmichthys Molitrix ◽  
Krasnodar Krai ◽  
Biological Resources

The author has carried out a retrospective analysis of environmental data about the Azov limans of the Krasnodar Krai. The increasing liman deterioration leading to their complete disappearance has been noted. Assessment of the priority of liman fish economy has been given. In terms of biological melioration there have been offered measures on stocking limans with herbivorous fish species of different age: grass carp Ctenopharyngodon idella and white silver carp Hypophthalmichthys molitrix , and determined necessary amounts of yearly stocking of the Azov limans. Modern data on the overgrowth in the water area of the Azov limans by higher aquatic vegetation have been presented in the context of the main groups of limans. The groups of limans were graded according to the priority of conducting biological melioration measures in them and practical recommendations were given on the quantity and places of stocking of the Azov limans grass carp and white silver carp depending on the degree of overgrowth. The necessity of using the funds received as compensation for the harm to water biological resources in the Krasnodar Krai for the artificial reproduction of grass carp and white silver carp and their introduction into the Azov limans has been substantiated. The article shows that stocking limans with herberous fish species will both ensure ameliorative effect and increase amount of fish commercial output.

Balancing Fisheries Management and Water Uses for Impounded River Systems

2008 ◽  
Keyword(s):  
Plant Species ◽  
Largemouth Bass ◽  
Grass Carp ◽  
Aquatic Vegetation ◽  
Micropterus Salmoides ◽  
Minimum Weight ◽  
Ctenopharyngodon Idella ◽  
Vegetation Coverage ◽  
Eurasian Watermilfoil ◽  
Parrot Feather

<em>Abstract</em>.—Lake Austin is a 648-ha riverine impoundment of the Colorado River located in central Texas and supports a trophy ($5.9 kg minimum weight) largemouth bass <em>Micropterus salmoides </em>fishery. Much of the reservoir is bordered by waterfront homes and, in addition to largemouth bass anglers, also is used by recreational boaters. Aquatic vegetation management on this reservoir has been an issue of concern since the 1950s. Parrot feather <em>Myriophyllum aquaticum </em>and Eurasian watermilfoil <em>M. spicatum </em>were the traditional species of concern but were successfully controlled with winter drawdowns. In 1999, hydrilla <em>Hydrilla verticillata </em>(9 ha) was documented for the first time, and by 2002, coverage had expanded to 130 ha. A hydrilla management plan was developed by a multistakeholder group that included biological (including triploid grass carp <em>Ctenopharyngodon idella</em>), mechanical, physical (reservoir drawdowns), and chemical management options. Of these options, most attention was given to the use of triploid grass carp. Many waterfront property owners viewed grass carp as the only reasonable solution, while largemouth bass angling groups vehemently opposed this management option. After much discussion, the stakeholder group decided that a slow methodical approach to triploid grass carp use, with a number of incremental stockings, might have a chance of successfully reducing hydrilla coverage without denuding the reservoir of all aquatic vegetation. The strategy was to increase the number of grass carp slowly until there were just enough in the reservoir to control hydrilla but not so many as to eliminate less preferred plant species. After an initial stocking in February 2003, the number of additional grass carp stocked was based on results of hydrilla coverage surveys conducted at 2–4-month intervals during the growing season. From February 2003 through November 2004, a total of 8,125 triploid grass carp were stocked in six stockings. The number of grass carp per hectare of hydrilla ranged from 29.2 to 68.3 until coverage declined in December 2004 to 34 ha. From February 2005 to March 2007, hydrilla coverage ranged from only 1 to 27 ha (0.1–4.2% coverage) while other plant species less preferred by grass carp, primarily Eurasian watermilfoil expanded. As a result, mean total vegetation coverage from February 2005 to March 2007 was 17% and continued to provide habitat for largemouth bass. Grass carp stockings were reinitiated in October 2006 when hydrilla coverage increased to 27 ha. In 2005 and 2006, the incremental stocking strategy implemented at Lake Austin appeared to help control hydrilla without denuding the reservoir of all aquatic vegetation. Cooperators and interest groups seemed satisfied with the strategy and results.

The Biology of Invasive Alien Plants in Canada. 7. Cabomba caroliniana A. Gray

2007 ◽  
Vol 87 (3) ◽  
pp. 615-638 ◽  
Author(s):  
Claire E Wilson ◽  
Stephen J Darbyshire ◽  
Rosita Jones
Keyword(s):  
United States ◽  
Aquatic Plant ◽  
Integrated Management ◽  
Fish Habitat ◽  
The United States ◽  
Management Plan ◽  
Management Tools ◽  
Surrounding Water ◽  
Cabomba Caroliniana ◽  
Asian Pacific

The freshwater aquatic plant Cabomba caroliniana, or fanwort, was recently reported in a lake northeast of Peterborough, Ontario, where it has successfully established and survived winter conditions since at least 1991. This is the first documented occurrence of fanwort becoming naturalized in Canada. Fanwort is a popular aquarium plant that is native to South America and possibly the southeastern United States and has been introduced in several Asian, Pacific and European countries through the discarding or deliberate planting of aquarium plants in natural waterways. It is particularly invasive in China, Japan and Australia, and in parts of the United States, where its range is spreading. Fanwort grows rapidly and forms dense stands that clog waterways, impeding flow, obstructing navigation, altering fish habitat and excluding other vegetation. It does not produce mature seed in the northern parts of its North American range, but can multiply clonally and spread quickly by stem fragmentation. It produces turion-like stems at the end of the growing season, which assist in over-wintering under adverse conditions. Fanwort is difficult to control with herbicides and is resistant to mechanical management techniques as populations can quickly re-establish from plant fragments. Populations near the Trent-Severn Waterway in Canada are extensively established and management tools are not available to attempt eradication. An integrated management plan that focuses on early detection and rapid response in surrounding water bodies may succeed in mitigating the economic and environmental impacts and limiting the spread of fanwort. Key words: Cabomba caroliniana, fanwort, cabomba de Caroline, CABCA, aquatic plant, weed biology, invasive alien

A Survey of the New River Aquatic Plant Community in Response to Recent Triploid Grass Carp Introductions into Claytor Lake, Virginia

2015 ◽  
Vol 14 (2) ◽  
pp. 308-318 ◽  
Author(s):  
Matthew A. Weberg ◽  
Brian R. Murphy ◽  
Andrew L. Rypel ◽  
John R. Copeland
Keyword(s):  
Plant Community ◽  
Grass Carp ◽  
Aquatic Plant
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