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.

Fishing Mortality and Habitat Loss Affect Largemouth Bass Fishery in the Potomac River (Maryland)

2017 ◽  
Vol 8 (1) ◽  
pp. 140-153 ◽  
Author(s):  
Joseph W. Love ◽  
Mary Groves ◽  
Branson D. Williams
Keyword(s):  
Population Size ◽  
Habitat Loss ◽  
Largemouth Bass ◽  
Aquatic Vegetation ◽  
Micropterus Salmoides ◽  
The United States ◽  
Potomac River ◽  
Fishing Mortality ◽  
Catch And Release ◽  
Negative Impacts

Abstract Largemouth Bass Micropterus salmoides is arguably the most popular sport fish of inland waters in the United States. The majority of anglers in the fishery practice catch and release. Catch-and-release guidelines aim to reduce negative impacts of angling on individual fish, though such impacts on populations are not widely reported. We hypothesized that a decline in the population size for Largemouth Bass from a catch-and-release fishery from the Potomac River resulted from a period of greater fishing mortality followed by habitat loss that reduced the recovery of the population. After we analyzed several years of fishery-dependent and independent data (1999–2015), it was determined that fishing mortality and relative exploitation were greater than average in the latter half of the 2000s than in previous years. Fishery-independent survey results suggested a loss of large fish and decline in population size. The relative abundance of juveniles subsequently declined possibly because the area of submerged aquatic vegetation used as nursery habitat had declined after tropical storms. For management purposes, we suggest that fishing mortality not exceed 28% for a sustainable fishery (assuming similar levels of natural mortality) in the Potomac River. Negative impacts to Largemouth Bass populations could be lessened by reduced harvest and widespread enforcement of catch-and-release guidelines, especially during times when angler effort is high, fish are highly accessible to anglers in the fishery, and habitat loss limits recruitment.

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.

Use of underwater video to assess freshwater fish populations in dense submersed aquatic vegetation

2015 ◽  
Vol 66 (1) ◽  
pp. 10 ◽  
Author(s):  
Kyle L. Wilson ◽  
Micheal S. Allen ◽  
Robert N. M. Ahrens ◽  
Michael D. Netherland
Keyword(s):  
Relative Abundance ◽  
Largemouth Bass ◽  
Aquatic Vegetation ◽  
Micropterus Salmoides ◽  
Hydrilla Verticillata ◽  
Submersed Aquatic Vegetation ◽  
Underwater Video ◽  
Point Counts ◽  
Abundance Estimates ◽  
Total Fish

Underwater video cameras (UVC) provide a non-lethal technique to sample fish in dense submersed aquatic vegetation. Fish often inhabit densely vegetated areas, but deficiencies of most sampling gears bias relative abundance estimates that inform fisheries management. This study developed methods using UVC to estimate relative abundance in dense vegetation using three experimental ponds covered with surface-matted hydrilla (Hydrilla verticillata) stocked at different densities of Lepomis spp. and largemouth bass (Micropterus salmoides). We conducted UVC point counts over 13 weeks to measure relative fish abundance and occurrence from video analysis. Ponds were then drained to obtain true fish densities. In total, fish were detected in 55% of all counts and juvenile and adult Lepomis spp. and largemouth bass were enumerated. End-of-season true fish densities ranged across ponds (from 52 to 37000 fishha–1). Additionally, pond 2’s true density changed substantially from 370 to 12300 fishha–1. True population size was accurately reflected in differences in estimated relative abundances obtained from fish counts, as in pond 2 where mean fish counts increased from 0.10 in week 1 to 2.33 by week 13. Underwater video accurately and precisely quantified relative abundance at naturally-occurring fish densities, but this success was reduced at low densities.

scholarly journals Recruitment dynamics of non-native largemouth bass within the Sacramento-San Joaquin Delta

2020 ◽  
Author(s):  
Brock M. Huntsman ◽  
Frederick Feyrer ◽  
Matthew J. Young ◽  
James A. Hobbs ◽  
Shawn Acuña ◽  
...  
Keyword(s):  
Population Structure ◽  
Largemouth Bass ◽  
Aquatic Vegetation ◽  
Micropterus Salmoides ◽  
Habitat Characteristics ◽  
Fish Community Structure ◽  
Health Indices ◽  
Young Of The Year ◽  
Overwinter Mortality ◽  
Critical Developmental Period

Largemouth bass (Micropterus salmoides, LMB) recruitment is limited by a critical developmental period during early life-stages, but this mechanism may be less significant within non-native habitats. We conducted boat electrofishing surveys in four tidal lakes of California’s Sacramento-San Joaquin Delta (SSJD) from 2010-2011 to describe introduced LMB recruitment dynamics. We evaluated growth, proximate composition, and health indices of young-of-the-year (YOY) LMB among tidal lakes and developed an integrated count model to determine how factors known to affect LMB recruitment shape SSJD population structure. Our results show a mismatch between growth, nutrition, and YOY abundance, where the tidal lake with the most abundant and fastest growing LMB had the poorest nutritional status. The warm winter water temperatures and lack of a hatching-cohort growth advantage suggests overwinter starvation plays a less significant role in SSJD LMB recruitment than many native LMB habitats. Collectively, our results suggest that habitat characteristics (submerged aquatic vegetation) and not overwinter mortality shapes SSJD LMB population structure, a mechanism consistent with contemporary hypotheses about the altered fish community structure of the SSJD.

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.

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