Declines in the energy content of yearling non‐native alewife associated with lower food web changes in Lake Michigan

Juveniles of non‐native alewife, Alosa pseudoharengus (Wilson), were collected in Lake Michigan in 1998, 1999, 2010, 2011 and 2013 to evaluate changes in energy content during a period of major ecosystem changes. Consistent with historical data, energy content of yearling alewife declined from late winter into late spring and was at its lowest point in June. Energy density and length‐adjusted, entire‐body energy were lower in 2010, 2011 and 2013 than in 1998 and 1999. Energy losses over the first winter in the lake were more severe for the 2010 year class (56% decrease) than for the 1998 year class (28% decrease). Alewife diets in late spring of 2010–2013 reflected the loss of major prey such as Diporeia spp. and a shift towards lower energy prey. The recent decline in energy content of yearling alewife can be linked to recent changes in productivity and abundance of key components of the lower food web of Lake Michigan following the dreissenid invasion.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109567/1/fme12092.pd

Evaluating consumptive and nonconsumptive predator effects on prey density using field time‐series data

Determining the degree to which predation affects prey abundance in natural communities constitutes a key goal of ecological research. Predators can affect prey through both consumptive effects (CEs) and nonconsumptive effects (NCEs), although the contributions of each mechanism to the density of prey populations remain largely hypothetical in most systems. Common statistical methods applied to time‐series data cannot elucidate the mechanisms responsible for hypothesized predator effects on prey density (e.g., differentiate CEs from NCEs), nor can they provide parameters for predictive models. State‐space models (SSMs) applied to time‐series data offer a way to meet these goals. Here, we employ SSMs to assess effects of an invasive predatory zooplankter, Bythotrephes longimanus, on an important prey species, Daphnia mendotae, in Lake Michigan. We fit mechanistic models in an SSM framework to seasonal time series (1994–2012) using a recently developed, maximum‐likelihood–based optimization method, iterated filtering, which can overcome challenges in ecological data (e.g., nonlinearities, measurement error, and irregular sampling intervals). Our results indicate that B. longimanus strongly influences D. mendotae dynamics, with mean annual peak densities of B. longimanus observed in Lake Michigan estimated to cause a 61% reduction in D. mendotae population growth rate and a 59% reduction in peak biomass density. Further, the observed B. longimanus effect is most consistent with an NCE via reduced birth rates. The SSM approach also provided estimates for key biological parameters (e.g., demographic rates) and the contribution of dynamic stochasticity and measurement error. Our study therefore provides evidence derived directly from survey data that the invasive zooplankter B. longimanus is affecting zooplankton demographics and offer parameter estimates needed to inform predictive models that explore the effect of B. longimanus under different scenarios, such as climate change.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148243/1/ecy2583-sup-0001-AppendixS1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148243/2/ecy2583_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148243/3/ecy2583.pd

A trophic bottleneck?: The ecological role of trout‐perch P ercopsis omiscomaycus in S aginaw B ay, L ake H uron

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97230/1/jai12023.pd

Let’s Build a Picnic Table.

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Influence of Diporeia Density on Diet Composition, Relative Abundance, and Energy Density of Planktivorous Fishes in Southeast Lake Michigan

The benthic amphipod Diporeia spp. is an important prey for many fish in offshore areas of the Great Lakes, but its abundance has been rapidly decreasing. To assess the influence of Diporeia availability on the food habits, relative abundance, and energetics of planktivorous fish, the diet composition, catch per unit effort (CPUE), and energy density of plantkivorous fish in southeast Lake Michigan during 2000–2001 were compared among locations with different Diporeia densities. Diporeia densities at St. Joseph, Michigan, were near 0/m2 over much of the bottom but averaged more than 3,800/m2 at Muskegon and Little Sable Point, Michigan. Consistent with these differences in Diporeia density, fish diet composition, CPUE, and energy density varied spatially. For example, alternative prey types comprised a larger fraction of the diets of bloater Coregonus hoyi, large (>100 mm total length) alewife Alosa pseudoharengus, and slimy sculpin Cottus cognatus at St. Joseph than at Muskegon and Little Sable Point. This pattern was seasonally dependent for alewives and bloaters because Diporeia were eaten mainly in June. Food biomass per stomach was not lower at St. Joseph than elsewhere, suggesting that the spatial variation in diet composition was due to greater consumption of alternative prey by fish at St. Joseph. Although slimy sculpin and bloaters were able to feed on alternative prey, the CPUE of these species at certain depths was considerably lower at St. Joseph than at Muskegon or Little Sable Point, indicating that Diporeia availability may also influence fish abundance and distribution. Finally, a link between Diporeia density and fish energetics was suggested by the comparatively low energy density of deepwater sculpin Myoxocephalus thompsonii and large alewives at St. Joseph, a result that may reflect the low energy content of other prey relative to Diporeia.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141042/1/tafs0588.pd

Reliability of Bioelectrical Impedance Analysis for Estimating Whole‐Fish Energy Density and Percent Lipids

We evaluated bioelectrical impedance analysis (BIA) as a nonlethal means of predicting energy density and percent lipids for three fish species: Yellow perch Perca flavescens, walleye Sander vitreus, and lake whitefish Coregonus clupeaformis. Although models that combined BIA measures with fish wet mass provided strong predictions of total energy, total lipids, and total dry mass for whole fish, including BIA provided only slightly better predictions than using fish mass alone. Regression models that used BIA measures to directly predict the energy density or percent lipids of whole fish were generally better than those using body mass alone (based on Akaike’s information criterion). However, the goodness of fit of models that used BIA measures varied widely across species and at best explained only slightly more than one‐half the variation observed in fish energy density or percent lipids. Models that combined BIA measures with body mass for prediction had the strongest correlations between predicted and observed energy density or percent lipids for a validation group of fish, but there were significant biases in these predictions. For example, the models underestimated energy density and percent lipids for lipid‐rich fish and overestimated energy density and percent lipids for lipid‐poor fish. A comparison of observed versus predicted whole‐fish energy densities and percent lipids demonstrated that models that incorporated BIA measures had lower maximum percent error than models without BIA measures in them, although the errors for the BIA models were still generally high (energy density: 15‐18%; percent lipids: 82‐89%). Considerable work is still required before BIA can provide reliable predictions of whole‐fish energy density and percent lipids, including understanding how temperature, electrode placement, and the variation in lipid distribution within a fish affect BIA measures.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141722/1/tafs1519.pd

Temperature, recreational fishing and diapause egg connections : dispersal of spiny water fleas (Bythotrephes longimanus)

© The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License. The definitive version was published in Biological Invasions 13 (2011): 2513-2531, doi:10.1007/s10530-011-0078-8.The spiny water flea (Bythotrephes longimanus) is spreading from Great Lakes coastal waters into northern inland lakes within a northern temperature-defined latitudinal band. Colonization of Great Lakes coastal embayments is assisted by winds and seiche surges, yet rapid inland expansion across the northern states comes through an overland process. The lack of invasions at Isle Royale National Park contrasts with rapid expansion on the nearby Keweenaw Peninsula. Both regions have comparable geology, lake density, and fauna, but differ in recreational fishing boat access, visitation, and containment measures. Tail spines protect Bythotrephes against young of the year, but not larger fish, yet the unusual thick-shelled diapausing eggs can pass through fish guts in viable condition. Sediment traps illustrate how fish spread diapausing eggs across lakes in fecal pellets. Trillions of diapausing eggs are produced per year in Lake Michigan and billions per year in Lake Michigamme, a large inland lake. Dispersal by recreational fishing is linked to use of baitfish, diapausing eggs defecated into live wells and bait buckets, and Bythothephes snagged on fishing line, anchor ropes, and minnow seines. Relatively simple measures, such as on-site rinsing of live wells, restricting transfer of certain baitfish species, or holding baitfish for 24 h (defecation period), should greatly reduce dispersal.Study of Lakes Superior and Michigan was funded from NSF OCE-9726680 and OCE-9712872 to W.C.K., OCE-9712889 to J. Churchill. Geographic survey sampling and Park studies in the national parks during 2008-2010 were funded by a grant from the National Park Service Natural Resource Preservation Program GLNF CESU Task Agreement No. J6067080012

International Consensus Statement on Rhinology and Allergy: Rhinosinusitis

Background: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR‐RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR‐RS‐2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence‐based findings of the document. Methods: ICAR‐RS presents over 180 topics in the forms of evidence‐based reviews with recommendations (EBRRs), evidence‐based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results: ICAR‐RS‐2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence‐based management algorithm is provided. Conclusion: This ICAR‐RS‐2021 executive summary provides a compilation of the evidence‐based recommendations for medical and surgical treatment of the most common forms of RS