Bythotrephes Cederstroemi in Ohio Reservoirs: Evidence from Fish Diets (original) (raw)
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Bioenergetic analysis of prey consumption by Bythotrephes cederstroemi in Lake Michigan
Canadian Journal of Fisheries and Aquatic Sciences, 1995
A bioenergetic model for Bythotrephes cederstroemi was constructed using measured physiological parameters to predict predation rates. The model predicts that juvenile B. cederstroemi will consume approximately 150% of their body weight per day, while adults consume 118% of their body weight per day. These rates are consistent with those of other invertebrate crustaceans. The predicted rate was twice that of an experimental measurement reported for Lake Huron B. cederstroemi; this discrepancy is attributed to experimental artifacts and to differences between B. cederstroemi populations in Lake Michigan and those in Lakes Huron and Erie. The model was most sensitive to estimation of ingestion and assimilation efficiencies and, secondarily, respiration coefficients. This model estimates the csnsumptisn rate of B. cederstroemi in Lake Michigan under optimal food resource conditions, and may be useful in predicting the future impact of B. cederstroemi predation on the zooplankton assemblages of other Bakes.
Journal of Great Lakes Research, 2015
The ability of planktivorous fishes to exert top-down control on Bythotrephes potentially has far-reaching impacts on aquatic food-webs, given previously described effects of Bythotrephes on zooplankton communities. We estimated consumption of Bythotrephes by planktivorous and benthivorous fishes, using bioenergetics and daily ration models at nearshore (18 m), intermediate (46 m), and offshore (110 m) depths along one western Lake Superior transect (April, and September-November) and two northern Lake Michigan transects (April, July, and September). In Lake Superior, consumption (primarily by cisco Coregonus artedi) exceeded Bythotrephes production at all offshore sites in September-November (up to 396% of production consumed) and at the intermediate site in November (842%) with no evidence of consumption nearshore. By comparing Bythotrephes biomass following months of excessive consumption, we conservatively concluded that top-down control was evident only at the offshore site during September-October. In Lake Michigan, consumption by fishes (primarily alewife Alosa pseudoharengus) exceeded production at nearshore sites (up to 178%), but not in deeper sites (b 15%). Evidence for top-down control in the nearshore was not supported, however, as Bythotrephes never subsequently declined. Using generalized additive models, temperature, and not fish consumption nor zooplankton prey density, best explained variability in Bythotrephes biomass. The non-linear pattern revealed Bythotrephes to increase with temperature up to 16°C, and then decline between 16 and 23°C. We discuss how temperature likely has direct negative impacts on Bythotrephes when temperatures near 23°C, but speculate that predation also contributes to declining biomass when temperatures exceed 16°C.
Population Characteristics of Bythotrephes in Lake Michigan
Journal of Great Lakes Research, 2003
The population characteristics of Bythotrephes were evaluated at seven nearshore (45 m) and eight offshore (80 to 150 m) stations in Lake Michigan during July and September 2000. Bythotrephes was generally most abundant at offshore stations, but mean density was patchy (4 to 1,326/m 2) among locations. During the year, there was a shift from reproduction by mainly instar III females to reproduction by instar II females. The shift generally reflected a change in the population structure of Bythotrephes at most sites during the same period. Bythotrephes populations in July were generally characterized by small body size at reproduction (instar II and III), large clutch size, and small neonates. Later in the season, body size at reproduction and neonates were larger and clutch size was smaller. Most growth (body length) of Bythotrephes occurred between instar I and II whereas little growth occurred between instar II and III. Spine length of Bythotrephes increased between July and September. The population characteristics and reproductive strategies of Bythotrephes appear to be adaptations to fish predation and food limitations.
Bythotrephes Cederstroemi: its New Appearance in Lake Michigan
Journal of Great Lakes Research, 1988
Bythotrephes cederstroemi was newly found in Lake Michigan in September 1986. This predaceous cladoceran was previously detected in Lake Huron (December 1984) and subsequently dispersed into Lakes Ontario and Erie (autumn 1985). It was previously known only from Europe. Entry into Lake Michigan may have occurred through the exchange of Lakes Huron and Michigan water masses in the Straits ofMackinac. Bythotrephes cederstroemi was consumed by Lake Michigan deepwater sculpins in October 1986. Since Bythotrephes is believed to be a surface-dwelling species, the most probable route by which it entered the sculpin diet was through the rapid sinking of dying (and dead) animals and their subsequent ingestion by sculpins at the sediment-water interface. Bythotrephes cederstroemi exhibited allometric and cyclomorphic growth. The caudal process was relatively straight in immature specimens and became progressively more kinked in larger (older) animals. Furthermore, the kink was more strongly developed in autumn (October) than summer. (July) B. cederstroemi populations. ADDITIONAL INDEX WORDS: Cladoceran, sculpins, dispersal, cyclomorphic growth.
Journal of Great Lakes Research, 2010
Bythotrephes were collected on a regular basis at a 110 m deep reference station in Lake Michigan over a 10year period 1994-2003. The measured population structure in conjunction with an updated bioenergetic model was used to estimate daily predation demands by Bythotrephes on the zooplankton community. The bioenergetic model incorporated the effect of temperature on growth and respiration and used a scalable size structure to adjust for a dynamic range in size across the season. A general linear model was developed to apply the bioenergetic results to routinely collected field data for estimating predation needs. Daily population consumption needs were estimated to be approximately equal to Bythotrephes standing biomass but varied as a function of water temperature and percent instar composition. At a temperature of 18°C the predation needs of the population were equal to the population biomass. At warmer temperatures (22-24°C) the daily needs were up to 35% above the population biomass. Within and across years the population was variable, while trend lines from the long-term data indicated biomass and predation needs had an initial peak in mid-August followed by a plateau period with a seasonal high peak mid-October. A decrease in the midseason long-term average size structure suggests that Bythotrephes may experience prey limitation during this time period of the year. Over the course of the 10-year period population cycles and peak biomass were fairly stable with no indication of a change in predation needs.
Journal of Great Lakes Research, 2004
Recently the exotic cladoceran Bythotrephes cederstroemi colonized inland lakes in the Upper Peninsula of Michigan, facing warmer temperatures and greater exposure to smaller fish than in coastal waters of Lake Superior. However, the long caudal appendage (spine) of Bythotrephes protects it against young-of-the-year (YOY) fish predation. After experience, small fish (30-60 mm TL) develop aversion behavior, explaining why this prey item rarely occurs in their stomachs, despite ingestion of other prey species with core body lengths between 2-3 mm. Here we compare laboratory and field size-dependent feeding patterns for YOY of two common fish species (yellow perch, Perca flavescens; bluegills, Lepomis macrochirus) with field patterns from a typical bait-fish species (spottail shiner, Notropis hudsonius). Behavioral responses of bluegills indicate that deterrence is not a simple linear function of spine length, but that longer spines offer disproportionate protection, explaining why long spines are present at birth. Stomach contents of small perch (30-60 mm TL) confirm size-dependent avoidance, with only occasional consumption of Bythotrephes and rare puncture of stomach walls. However, examples of ingestion and frequent stomach puncture were found in the thinner-walled stomachs of spottail shiners. Out of 140 small fish collected when this species encountered high densities of Bythotrephes, 77 had Bythotrephes in stomachs or lower digestive tracts, and 50 (65%) had spines protruding through gut walls. Clearly, this bait-fish species is capable not only of ingesting large numbers of Bythotrephes, but of receiving injury in the process.
Influences on Bythotrephes longimanus life-history characteristics in the Great Lakes
Journal of Great Lakes Research, 2012
We compared Bythotrephes population demographics and dynamics to predator (planktivorous fish) and prey (small-bodied crustacean zooplankton) densities at a site sampled through the growing season in Lakes Michigan, Huron, and Erie. Although seasonal average densities of Bythotrephes were similar across lakes (222/m 2 Erie, 247/m 2 Huron, 162/m 2 Michigan), temporal trends in abundance differed among lakes. In central Lake Erie where Bythotrephes' prey assemblage was dominated by small individuals (60%), where planktivorous fish densities were high (14,317/ha), and where a shallow water column limited availability of a deepwater refuge, the Bythotrephes population was characterized by a small mean body size, large broods with small neonates, allocation of length increases mainly to the spine rather than to the body, and a late summer population decline. By contrast, in Lake Michigan where Bythotrephes' prey assemblage was dominated by large individuals (72%) and planktivorous fish densities were lower (5052/ha), the Bythotrephes population was characterized by a large mean body size (i.e., 37-55% higher than in Erie), small broods with large neonates, nearly all growth in body length occurring between instars 1 and 2, and population persistence into fall. Life-history characteristics in Lake Huron tended to be intermediate to those found in Lakes Michigan and Erie, reflecting lower overall prey and predator densities (1224/ha) relative to the other lakes. Because plasticity in life history can affect interactions with other species, our findings point to the need to understand life-history variation among Great Lakes populations to improve our ability to model the dynamics of these ecosystems.
Channel Catfish Diets Include Substantial Vegetation in a Missouri River Reservoir
Channel catfish (Ictalurus punctatus) are native to Lake Sharpe, a Missouri River mainstem reservoir, and are common in angler catches. Channel catfish growth has declined since the formation of the reservoir in 1963. Mean lengths at time of capture for channel catfish ages 9, 10, 11, and 12 have decreased by 69, 55, 115, and 218 mm, respectively, since impoundment. The objective of this study was to document monthly food habits of channel catfish throughout the growing season (May-August) in Lake Sharpe to assess potential effects of diet on growth. Although channel catfish consumed both macroinvertebrates and fishes as expected, they also consumed large quantities of submergent aquatic vegetation. Consumed vegetation contributed 38–73% of the diet by weight over 2 channel catfish length groups (<280 mm and ≥280 mm total length) during the 4 months sampled. Consumption of substantial amounts of vegetation should be considered a suboptimal diet for channel catfish growth. Consequently, diets of channel catfish in Lake Sharpe could be a factor contributing to the observed slow growth of older catfish in this population.
Biological Invasions, 2009
Bighead and silver carp are well established in the Mississippi River basin following their accidental introduction in the 1980s. Referred to collectively as Asian carp, these species are filter feeders consuming phytoplankton and zooplankton. We examined diet overlap and electivity of Asian carp and three native filter feeding fishes, bigmouth buffalo, gizzard shad, and paddlefish, in backwater lakes of the Illinois and Mississippi rivers. Rotifers, Keratella spp., Brachionus spp., and Trichocerca spp., were the most common prey items consumed by Asian carp and gizzard shad, whereas crustacean zooplankton were the preferred prey of paddlefish. Bigmouth buffalo diet was broad, including both rotifers and crustacean zooplankton. Dietary overlap with Asian carp was greatest for gizzard shad followed by bigmouth buffalo, but we found little diet overlap for paddlefish. Diet similarity based on taxonomy correlated strongly with diet similarity based on size suggesting filtration efficiency influenced the overlap patterns we observed. Although rotifers were the most common prey item consumed by both bighead and silver carp, we found a negative relation between silver carp CPUE and cladoceran density. The competitive effect of Asian carp on native fishes may be forestalled because of the high productivity of Illinois and Mississippi river habitats, yet the potential for negative consequences of Asian carp in less productive ecosystems, including Lake Michigan, should not be underestimated.