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James F Kitchell - One of the best experts on this subject based on the ideXlab platform.
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stocking piscivores to improve fishing and water clarity a synthesis of the lake mendota biomanipulation project
Freshwater Biology, 2002Co-Authors: Brett M Johnson, M T Vogelsang, S R Carpenter, John J Magnuson, Thomas R. Hrabik, Richard C Lathrop, James F Kitchell, Timothy B. Johnson, Lars G RudstamAbstract:SUMMARY 1. A total of 2.7 · 10 6 walleye fingerlings and 1.7 · 10 5 northern pike fingerlings were stocked during 1987–99 in eutrophic Lake Mendota. The objectives of the biomanipulation were to improve sport fishing and to increase piscivory to levels that would reduce Planktivore biomass, increase Daphnia grazing and ultimately reduce algal densities in the lake. The combined biomass of the two piscivore species in the lake increased rapidly from < 1 kg ha )1 and stabilised at 4–6 kg ha )1 throughout the evaluation period. 2. Restrictive harvest regulations (i.e. increase in minimum size limit and reduction in bag limit) were implemented in 1988 to protect the stocked piscivores. Further restrictions were added in 1991 and 1996 for walleye and northern pike, respectively. These restrictions were essential because fishing pressure on both species (especially walleye) increased dramatically during biomanipulation. 3. Commencing in 1987 with a massive natural die-off of cisco and declining yellow perch populations, total Planktivore biomass dropped from about 300–600 kg ha )1 prior to the die-off and the fish stocking, to about 20–40 kg ha )1 in subsequent years. These low Planktivore biomasses lasted until a resurgence in the perch population in 1999. 4. During the period prior to biomanipulation when cisco were very abundant, the dominant Daphnia species was the smaller-bodied D. galeata mendotae, which usually reached a biomass maximum in June and then crashed shortly thereafter. Beginning in 1988, the larger-bodied D. pulicaria dominated, with relatively high biomasses occurring earlier in the spring and lasting well past mid-summer of many years. 5. In many years dominated by D. pulicaria, Secchi disc readings were greater during the spring and summer months when compared with years dominated by D. galeata mendotae. During the biomanipulation evaluation period, phosphorus (P) levels also changed dramatically thus complicating our analysis. Earlier research on Lake Mendota had shown that Daphnia grazing increased summer Secchi disc readings, but P concentrations linked to agricultural and urban runoff and to climate-controlled internal mixing processes were also important factors affecting summer readings. 6. The Lake Mendota biomanipulation project has been a success given that high densities of the large-bodied D. pulicaria have continued to dominate for over a decade, and the
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Stocking piscivores to improve fishing and water clarity: a synthesis of the Lake Mendota biomanipulation project
Freshwater Biology, 2002Co-Authors: Richard C Lathrop, Brett M Johnson, M T Vogelsang, John J Magnuson, Thomas R. Hrabik, James F Kitchell, Lars G Rudstam, Timothy B. Johnson, Stephen R. Carpenter, R. S. StewartAbstract:1. A total of 2.7 × 10 6 walleye fingerlings and 1.7 × 10 5 northern pike fingerlings were stocked during 1987-99 in eutrophic Lake Mendota. The objectives of the biomanipulation were to improve sport fishing and to increase piscivory to levels that would reduce Planktivore biomass, increase Daphnia grazing and ultimately reduce algal densities in the lake. The combined biomass of the two piscivore species in the lake increased rapidly from < 1 kg ha -1 and stabilised at 4-6 kg ha -1 throughout the evaluation period. 2. Restrictive harvest regulations (i.e. increase in minimum size limit and reduction in bag limit) were implemented in 1988 to protect the stocked piscivores. Further restrictions were added in 1991 and 1996 for walleye and northern pike, respectively. These restrictions were essential because fishing pressure on both species (especially walleye) increased dramatically during biomanipulation. 3. Commencing in 1987 with a massive natural die-off of cisco and declining yellow perch populations, total Planktivore biomass dropped from about 300-600 kg ha -1 prior to the die-off and the fish stocking, to about 20-40 kg ha -1 in subsequent years. These low Planktivore biomasses lasted until a resurgence in the perch population in 1999. 4. During the period prior to biomanipulation when cisco were very abundant, the dominant Daphnia species was the smaller-bodied D. galeata mendotae, which usually reached a biomass maximum in June and then crashed shortly thereafter. Beginning in 1988, the larger-bodied D. pulicaria dominated, with relatively high biomasses occurring earlier in the spring and lasting well past mid-summer of many years. 5. In many years dominated by D. pulicaria, Secchi disc readings were greater during the spring and summer months when compared with years dominated by D. galeata mendotae. During the biomanipulation evaluation period, phosphorus (P) levels also changed dramatically thus complicating our analysis. Earlier research on Lake Mendota had shown that Daphnia grazing increased summer Secchi disc readings, but P concentrations linked to agricultural and urban runoff and to climate-controlled internal mixing processes were also important factors affecting summer readings. 6. The Lake Mendota biomanipulation project has been a success given that high densities of the large-bodied D. pulicaria have continued to dominate for over a decade, and the diversity of fishing opportunities have improved for walleye, northern pike and, more recently, yellow perch.
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persistence of net heterotrophy in lakes during nutrient addition and food web manipulations
Limnology and Oceanography, 2000Co-Authors: Jonathan J Cole, Stephen R. Carpenter, Michael L Pace, James F KitchellAbstract:Net ecosystem production (NEP) is the difference between gross primary production (GPP) and community respiration (R). We estimated in situ NEP using three independent approaches (net CO2 gas flux, net O 2 gas flux, and continuous diel O2 measurements) over a 4‐7 yr period in a series of small lakes in which food webs were manipulated and nutrient loadings were experimentally varied. In the absence of manipulation, these lakes were net heterotrophic according to all three approaches. NEP (NEP 5 GPP-R) was consistently negative and averaged 235.5 6 3.7 (standard error) mmol C m 22 d 21 . Nutrient enrichment, in the absence of strong planktivory, tended to cause increases in estimates of both GPP and R (estimated from the continuous O2 data) but resulted in little change in the GPP/R ratio, which remained ,1, or NEP, which remained negative. When planktivorous fish dominated the food web, large zooplankton were rare and nutrient enrichment produced positive values of NEP by all three methods. Among lakes and years, daily values of NEP ranged from 2241 to 1175 mmol m 22 d 21 ; mean seasonal NEP was positive only under a combination of high nutrient loading and a Planktivore-dominated food web. Community R is significantly subsidized by allochthonous sources of organic matter in these lakes. Combining all lakes and years, we estimate that ;26 mmol C m 22 d 21 of allochthonous origin is respired on average. This respiration of allochthonous organic matter represents 13 to 43% of total R, and this fraction declines with increasing GPP.
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seasonal effects of variable recruitment of a dominant piscivore on pelagic food web structure
Limnology and Oceanography, 1997Co-Authors: David M Post, James F Kitchell, Stephen R. Carpenter, David L Christensen, Kathryn L Cottingham, Daniel E Schindler, James R HodgsonAbstract:Piscivorous fish play an important role in regulating lake food web structure. However, most ultimately piscivorous fish pass through a period of planktivory before becoming piscivorous. In 1993 and 1994, two large cohorts of young-of-the-year largemouth bass (Micropterus salmoides) were recorded in Paul Lake, Michigan. The 1993 and 1994 cohorts were the largest recorded in data extending back to 1984 and occurred during a period in which adult and juvenile bass biomass was low. In 1993, consumption of large-bodied zooplankton by the young-of-theyear cohort eliminated large-bodied cladocerans by the middle of August. As large cladocerans declined, small cladocerans, especially Bosminu Zongirostris, increased. By early Septcmbcr the biomass of B. Zongirostris was similar to that of the entire cladoceran community in previous years. Coincident with the shifts in the cladoceran community were increases in epilimnetic Chl a concentrations <35 pm. However, total cpilimnetic Chl a did not increase. In contrast, the 1994 cohort had no discernible effect on pelagic food web structure because production of large-bodied zooplankton rapidly exceeded predation. Our results show the potential for large cohorts of piscivorous fish to affect food web structure, at a seasonal scale, through intense planktivory.
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the trophic cascade in lakes
1996Co-Authors: James F KitchellAbstract:1. Cascading trophic interactions 2. Experimental lakes, manipulations and measurements 3. Statistical analysis of the ecosystem experiments 4. The fish populations 5. Fish behavioral and community responses to manipulation 6. Roles of fish predation: piscivory and planktivory 7. Dynamics of the phantom midge: implications for zooplankton 8. Zooplankton community dynamics 9. Effects of predators and food supply and diel vertical migration of Daphnia 10. Zooplankton biomass and body size 11. Phytoplankton community dynamics 12. Metalimnetic phytoplankton 13. Primary production and its interactions with nutrients and light transmission 14. Heterotrophic microbial processes 15. Annual fossil record of food-web manipulation 16. Simulation models of the trophic cascade: predictions and evaluations 17. Synthesis and new directions Index.
Roy A Stein - One of the best experts on this subject based on the ideXlab platform.
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quantifying responses to hybrid striped bass predation across multiple trophic levels implications for reservoir biomanipulation
Transactions of The American Fisheries Society, 1996Co-Authors: John M Dettmers, Dennis R. Devries, Roy A SteinAbstract:Abstract Top-down effects from piscivores to phytoplankton have been documented in north temperate lakes, thus permitting managers to regulate these food webs. From our review of the literature, reservoir trophic interactions appear less amenable to biomanipulation owing to the presence of a fast-growing, omnivorous Planktivore, gizzard shad Dorosoma cepedianum. If reservoir zooplankton can be enhanced by reducing gizzard shad through biomanipulation, this could increase survival of food-limited early life stages of sport fishes dependent on zooplankton and could improve water clarity by reducing phytoplankton. To quantify this potential, we evaluated responses of age-0 gizzard shad, crustacean zooplankton, and phytoplankton to the addition of hybrid striped bass Morone saxatilis × M. chrysops (22 kg/ha) to four of eight 0.4-ha ponds. Hybrid striped bass nearly eliminated age-0 gizzard shad from ponds within 10 d after being stocked, which permitted zooplankton density and size to increase but had no effe...
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food web regulation by a Planktivore exploring the generality of the trophic cascade hypothesis
Canadian Journal of Fisheries and Aquatic Sciences, 1995Co-Authors: Roy A Stein, Dennis R. Devries, John M DettmersAbstract:The trophic cascade hypothesis currently being tested in north temperate systems may not apply to open-water communities in lower latitude U.S. reservoirs. These reservoir communities differ dramatically from northern lakes in that an open-water omnivore, gizzard shad (Dorosoma cepedianum), often occurs in abundance. Neither controlled by fish predators (owing to high fecundity and low vulnerability) nor by their zooplankton prey (following the midsummer zooplankton decline, gizzard shad consume detritus and phytoplankton), gizzard shad regulate community composition rather than being regulated by top-down or bottom-up forces. In experiments across a range of spatial scales (enclosures, 1–9 m2; ponds, 4–5 ha; and reservoirs, 50–100 ha), we evaluated the generality of the trophic cascade hypothesis by assessing its conceptual strength in reservoir food webs. We reviewed the role of gizzard shad in controlling zooplankton populations and hence recruitment of bluegill, Lepomis macrochirus (via exploitative c...
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food web regulation by a Planktivore exploring the generality of the trophic cascade hypothesis
Canadian Journal of Fisheries and Aquatic Sciences, 1995Co-Authors: Roy A Stein, Dennis R. Devries, John M DettmersAbstract:The trophic cascade hypothesis currently being tested in north temperate systems may not apply to open-water communities in lower latitude U.S. reservoirs. These reservoir communities differ dramat...
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Planktivores and plankton dynamics effects of fish biomass and Planktivore type
Canadian Journal of Fisheries and Aquatic Sciences, 1992Co-Authors: Xavier Lazzaro, Roy A Stein, Ray W. Drenner, Durward J SmithAbstract:Funding for this project was provided by ORSTOM action 2CA301 to X.L., NSF grant BSR-8906653 to R.W.D. and J.D.S., NSF grant BSR-9107173 to R.A.S., and the OSU Aquatic Ecology Laboratory.
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complex interactions between fish and zooplankton quantifying the role of an open water Planktivore
Canadian Journal of Fisheries and Aquatic Sciences, 1992Co-Authors: Dennis R. Devries, Roy A SteinAbstract:An open-water Planktivore, the gizzard shad (Dorosoma cepedianum), can drive complex interactions among fish and zooplankton in Ohio reservoirs. In Kokosing Lake, crustacean zooplankton density declined to near zero immediately after larval gizzard shad abundance peaked during 1987 and 1988. This decline can be attributed to increased death rates, due to predation, and to reduced number of eggs per cladoceran. In an enclosure/exclosure experiment, young-of-year gizzard shad at lake densities significantly reduced density of crustacean zooplankton and rotifers within 2 wk. In addition, phytoplankton that were edible to zooplankton were reduced in enclosures, likely due to a combination of direct herbivory by gizzard shad and reduced nutrient availability due to uptake by the growing gizzard shad. Gizzard shad not only directly influenced zooplankton via predation, they also indirectly affected zooplankton by reducing phytoplankton abundance. Because larval bluegill (Lepomis macrochira) migrated to the limn...
John M Dettmers - One of the best experts on this subject based on the ideXlab platform.
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quantifying responses to hybrid striped bass predation across multiple trophic levels implications for reservoir biomanipulation
Transactions of The American Fisheries Society, 1996Co-Authors: John M Dettmers, Dennis R. Devries, Roy A SteinAbstract:Abstract Top-down effects from piscivores to phytoplankton have been documented in north temperate lakes, thus permitting managers to regulate these food webs. From our review of the literature, reservoir trophic interactions appear less amenable to biomanipulation owing to the presence of a fast-growing, omnivorous Planktivore, gizzard shad Dorosoma cepedianum. If reservoir zooplankton can be enhanced by reducing gizzard shad through biomanipulation, this could increase survival of food-limited early life stages of sport fishes dependent on zooplankton and could improve water clarity by reducing phytoplankton. To quantify this potential, we evaluated responses of age-0 gizzard shad, crustacean zooplankton, and phytoplankton to the addition of hybrid striped bass Morone saxatilis × M. chrysops (22 kg/ha) to four of eight 0.4-ha ponds. Hybrid striped bass nearly eliminated age-0 gizzard shad from ponds within 10 d after being stocked, which permitted zooplankton density and size to increase but had no effe...
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food web regulation by a Planktivore exploring the generality of the trophic cascade hypothesis
Canadian Journal of Fisheries and Aquatic Sciences, 1995Co-Authors: Roy A Stein, Dennis R. Devries, John M DettmersAbstract:The trophic cascade hypothesis currently being tested in north temperate systems may not apply to open-water communities in lower latitude U.S. reservoirs. These reservoir communities differ dramatically from northern lakes in that an open-water omnivore, gizzard shad (Dorosoma cepedianum), often occurs in abundance. Neither controlled by fish predators (owing to high fecundity and low vulnerability) nor by their zooplankton prey (following the midsummer zooplankton decline, gizzard shad consume detritus and phytoplankton), gizzard shad regulate community composition rather than being regulated by top-down or bottom-up forces. In experiments across a range of spatial scales (enclosures, 1–9 m2; ponds, 4–5 ha; and reservoirs, 50–100 ha), we evaluated the generality of the trophic cascade hypothesis by assessing its conceptual strength in reservoir food webs. We reviewed the role of gizzard shad in controlling zooplankton populations and hence recruitment of bluegill, Lepomis macrochirus (via exploitative c...
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food web regulation by a Planktivore exploring the generality of the trophic cascade hypothesis
Canadian Journal of Fisheries and Aquatic Sciences, 1995Co-Authors: Roy A Stein, Dennis R. Devries, John M DettmersAbstract:The trophic cascade hypothesis currently being tested in north temperate systems may not apply to open-water communities in lower latitude U.S. reservoirs. These reservoir communities differ dramat...
Richard C Lathrop - One of the best experts on this subject based on the ideXlab platform.
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stocking piscivores to improve fishing and water clarity a synthesis of the lake mendota biomanipulation project
Freshwater Biology, 2002Co-Authors: Brett M Johnson, M T Vogelsang, S R Carpenter, John J Magnuson, Thomas R. Hrabik, Richard C Lathrop, James F Kitchell, Timothy B. Johnson, Lars G RudstamAbstract:SUMMARY 1. A total of 2.7 · 10 6 walleye fingerlings and 1.7 · 10 5 northern pike fingerlings were stocked during 1987–99 in eutrophic Lake Mendota. The objectives of the biomanipulation were to improve sport fishing and to increase piscivory to levels that would reduce Planktivore biomass, increase Daphnia grazing and ultimately reduce algal densities in the lake. The combined biomass of the two piscivore species in the lake increased rapidly from < 1 kg ha )1 and stabilised at 4–6 kg ha )1 throughout the evaluation period. 2. Restrictive harvest regulations (i.e. increase in minimum size limit and reduction in bag limit) were implemented in 1988 to protect the stocked piscivores. Further restrictions were added in 1991 and 1996 for walleye and northern pike, respectively. These restrictions were essential because fishing pressure on both species (especially walleye) increased dramatically during biomanipulation. 3. Commencing in 1987 with a massive natural die-off of cisco and declining yellow perch populations, total Planktivore biomass dropped from about 300–600 kg ha )1 prior to the die-off and the fish stocking, to about 20–40 kg ha )1 in subsequent years. These low Planktivore biomasses lasted until a resurgence in the perch population in 1999. 4. During the period prior to biomanipulation when cisco were very abundant, the dominant Daphnia species was the smaller-bodied D. galeata mendotae, which usually reached a biomass maximum in June and then crashed shortly thereafter. Beginning in 1988, the larger-bodied D. pulicaria dominated, with relatively high biomasses occurring earlier in the spring and lasting well past mid-summer of many years. 5. In many years dominated by D. pulicaria, Secchi disc readings were greater during the spring and summer months when compared with years dominated by D. galeata mendotae. During the biomanipulation evaluation period, phosphorus (P) levels also changed dramatically thus complicating our analysis. Earlier research on Lake Mendota had shown that Daphnia grazing increased summer Secchi disc readings, but P concentrations linked to agricultural and urban runoff and to climate-controlled internal mixing processes were also important factors affecting summer readings. 6. The Lake Mendota biomanipulation project has been a success given that high densities of the large-bodied D. pulicaria have continued to dominate for over a decade, and the
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Stocking piscivores to improve fishing and water clarity: a synthesis of the Lake Mendota biomanipulation project
Freshwater Biology, 2002Co-Authors: Richard C Lathrop, Brett M Johnson, M T Vogelsang, John J Magnuson, Thomas R. Hrabik, James F Kitchell, Lars G Rudstam, Timothy B. Johnson, Stephen R. Carpenter, R. S. StewartAbstract:1. A total of 2.7 × 10 6 walleye fingerlings and 1.7 × 10 5 northern pike fingerlings were stocked during 1987-99 in eutrophic Lake Mendota. The objectives of the biomanipulation were to improve sport fishing and to increase piscivory to levels that would reduce Planktivore biomass, increase Daphnia grazing and ultimately reduce algal densities in the lake. The combined biomass of the two piscivore species in the lake increased rapidly from < 1 kg ha -1 and stabilised at 4-6 kg ha -1 throughout the evaluation period. 2. Restrictive harvest regulations (i.e. increase in minimum size limit and reduction in bag limit) were implemented in 1988 to protect the stocked piscivores. Further restrictions were added in 1991 and 1996 for walleye and northern pike, respectively. These restrictions were essential because fishing pressure on both species (especially walleye) increased dramatically during biomanipulation. 3. Commencing in 1987 with a massive natural die-off of cisco and declining yellow perch populations, total Planktivore biomass dropped from about 300-600 kg ha -1 prior to the die-off and the fish stocking, to about 20-40 kg ha -1 in subsequent years. These low Planktivore biomasses lasted until a resurgence in the perch population in 1999. 4. During the period prior to biomanipulation when cisco were very abundant, the dominant Daphnia species was the smaller-bodied D. galeata mendotae, which usually reached a biomass maximum in June and then crashed shortly thereafter. Beginning in 1988, the larger-bodied D. pulicaria dominated, with relatively high biomasses occurring earlier in the spring and lasting well past mid-summer of many years. 5. In many years dominated by D. pulicaria, Secchi disc readings were greater during the spring and summer months when compared with years dominated by D. galeata mendotae. During the biomanipulation evaluation period, phosphorus (P) levels also changed dramatically thus complicating our analysis. Earlier research on Lake Mendota had shown that Daphnia grazing increased summer Secchi disc readings, but P concentrations linked to agricultural and urban runoff and to climate-controlled internal mixing processes were also important factors affecting summer readings. 6. The Lake Mendota biomanipulation project has been a success given that high densities of the large-bodied D. pulicaria have continued to dominate for over a decade, and the diversity of fishing opportunities have improved for walleye, northern pike and, more recently, yellow perch.
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the rise and fall of a dominant Planktivore direct and indirect effects on zooplankton
Ecology, 1993Co-Authors: Lars G Rudstam, Richard C Lathrop, S R CarpenterAbstract:We analyzed a 14-yr time series (1976-1989) of planktivorous fish and zooplankton from Lake Mendota, Wisconsin. Planktivory rates changed by an order of magnitude during this time period, primarily due to the rise and fall of the 1977 year class of cisco (Coregonus artedi) that dominated planktivory rates for a period of 10 yr. Plank- tivory increased between 1977 and 1978 due to an increase in biomass of that year class and decreased in August 1987 after a summer kill of cisco in the lake. Yellow perch (Perca flavescens) and other cisco year classes contributed <25% of the total planktivory during 1978 to 1987. Time series analysis revealed that this 10-yr pulse in planktivory rates was associated with changes in the Daphnia species and biomass. In years with low planktivory rates, higher biomass of daphnids dominated by Daphnia pulicaria developed earlier in the spring and lasted longer into the summer. This was also associated with an earlier and longer spring clear-water phase. In years with high planktivory rates, daphnid biomass was generally lower and dominated by the smaller Daphnia galeata mendotae. However, there was no significant effect of planktivory on the early summer peak in Daphnia biomass that is associated with a clear-water phase. The dynamics of this Daphnia peak are apparently regulated by Daphnia-algae interactions and not by planktivory rates. The seasonal and interyear changes in Daphnia species composition can be explained by the combined effects of planktivory, dynamics of food resources, and the physiological ecology of the two Daphnia species. There was no significant effect of increased planktivory on total zoo- plankton biomass due to a compensatory increase in cyclopoid copepods and no response by calanoid copepods. The recent history of Lake Mendota illustrates a 10-yr period of predation imposed by a single year class of a large, long-lived, obligate Planktivore. It is an example of variability in a lake ecosystem scaled to the life-span of a dominant fish species.
Norman D. Yan - One of the best experts on this subject based on the ideXlab platform.
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modification of the diel vertical migration of bythotrephes longimanus by the cold water Planktivore coregonus artedi
Freshwater Biology, 2008Co-Authors: Joelle D Young, Norman D. YanAbstract:Summary 1. The weak diel vertical migration observed in the large cladoceran Bythotrephes longimanus seems contradictory to the predator-avoidance hypothesis that predicts large zooplankton should have long migration amplitudes. However, cold-water Planktivores, especially Coregonus spp., are a main source of mortality for Bythotrephes and hence a deeper migration would result in a greater overlap with these hypolimnetic Planktivores. We hypothesized that Coregonus artedi (cisco) modifies the normal vertical migration pattern of Bythotrephes, such that the latter stays higher in the water column during the day and thus migrates less extremely at night. 2. The vertical distribution of Bythotrephes during the day was determined from single visits to six lakes in Ontario, Canada, all of which contain warm-water, epilimnetic Planktivores but differing in whether they contain cisco. One lake of each fish type was sampled day and night every 2–3 weeks over the ice-free season to examine daytime depths and migration amplitude. 3. The vertical migration of Bythotrephes differed in the presence and absence of cisco. In the lakes with cisco, there were significantly fewer Bythotrephes in the hypolimnion and they were higher in the water column during the day. Migration amplitude was smaller in the cisco than in the non-cisco lake. These observations were not attributable to differences in physical factors, and, although not conclusively attributable to cisco, are consistent with an effect of cisco. 4. We suggest that diurnal depth selection by Bythotrephes in lakes containing cisco is a trade-off between the risk of predation by warm- versus cold-water predators, balanced by the benefits of increased temperature and feeding rates near the surface. Even in lakes without cisco, however, the vertical migration of Bythotrephes was less than expected, suggesting that diurnal depth selection is a balance between the risk from warm-water Planktivores and access to sufficient light to feed effectively.