Identification of Stocked Muskellunge and Potential for Distinguishing Hatchery-Origin and Wild Fish Using Pelvic Fin Ray Microchemistry

The effectiveness of pelvic fin ray microchemistry of muskellunge Esox masquinongy Mitchill to identify stocked individuals along with the potential to identify naturally reproduced fish were evaluated. Fish and water samples were obtained from one hatchery and seven lakes with natural differences in water Sr:Ca to determine whether location-specific environmental signatures were recorded in sectioned muskellunge pelvic fin rays, including fish of known environmental history. Water and fin ray Sr:Ca were strongly correlated. Six lakes in Illinois possessed Sr:Ca signatures that were distinct from the hatchery where muskellunge were raised, resulting in pronounced shifts in Sr:Ca across sectioned fin rays of stocked fish. Hatchery and lake-specific Sr:Ca signatures were stable across years. Sixteen of 19 individual fish known to have been stocked based on PIT tags implanted at stocking were correctly identified as hatchery-origin fish using fin ray core Sr:Ca. Results also indicated that the hatchery Sr:Ca signal can be retained for at least seven years in fin rays of stocked fish. Fin ray microchemistry is a non-lethal approach for determining environmental history of muskellunge that could be used to assess movement patterns in lake and river systems and the degree to which muskellunge populations are supported by natural reproduction and stocking

Fatty Acid Profiles are Biomarkers of Fish Habitat Use in a River-Floodplain Ecosystem

Fatty acid (FA) analyses of fish tissues offer the potential to gain new knowledge of habitat or forage-specific energy inputs to fishes in river-floodplain ecosystems, although limited information exists regarding among-habitat differences in FA biomarkers. The goal of this study was to determine if differences in fish FA profiles among main channel and connected and disconnected floodplain lakes exist in large river-floodplain systems. Bluegill Lepomis macrochirus FA profiles were generated to assess differences among two reaches of the Illinois River, USA, and its connected and disconnected floodplain lakes and determine whether FA signatures could be used to reclassify fish to their source habitat. Bluegill FA profiles differed among habitats and river reaches, including differences in levels of individual FAs (e.g., 18:2n-6, an indicator of allochthonous inputs, was higher among main channel fish) and FA groupings (e.g., n-3:n-6 FA ratio, an indicator of aquatic primary productivity, was higher among floodplain lake fish), which enabled [87.5% reclassification accuracy of fish to their source environment. We demonstrated that bluegill FA profiles differed among reaches and laterally among river channel and floodplain habitats, suggesting that FA profiles can be used to infer recent habitat use and habitat-specific foraging of fishes in large river-floodplain ecosystems

Recruitment Sources of Channel and Blue Catfishes Inhabiting the Middle Mississippi River

Insight into environments that contribute recruits to adult fish stocks in riverine systems is vital for effective population management and conservation. Catfish are an important recreational species in the Mississippi River and are commercially harvested. However, contributions of main channel and tributary habitats to catfish recruitment in large rivers are unknown. Stable isotope and trace elemental signatures in otoliths are useful for determining environmental history of fishes in a variety of aquatic systems, including the Mississippi River. The objectives of this study were to identify the principal natal environments of channel catfish Ictalurus punctatus and blue catfish I. furcatus in the middle Mississippi River (MMR) using otolith stable oxygen isotopic composition (δ18O) and strontium:calcium ratios (Sr:Ca). Catfishes were sampled during July-October 2013-2014 and lapilli otoliths were analyzed for δ18O and Sr:Ca. Water samples from the MMR and tributaries were collected seasonally from 2006-2014 to characterize site-specific signatures. Persistent differences in water δ18O and Sr:Ca among the MMR and tributaries (including the upper Mississippi, Illinois, and Missouri rivers as well as smaller tributaries) were evident, enabling identification of natal environment for individual fish. Blue and channel catfish stocks in the MMR primarily recruited from the large rivers (Missouri and Mississippi) in our study area, with minimal contributions from smaller tributaries. Recruitment and year class strength investigations and efforts to enhance spawning and nursery habitats should be focused in the large rivers with less emphasis in smaller tributaries

Contrasting Population Characteristics of Yellow Bass (Morone mississippiensis) in Two Southern Illinois Reservoirs

We investigated two southern Illinois reservoirs with contrasting size structures of yellow bass (Morone mississippiensis) to compare growth, mortality and recruitment patterns. Yellow bass were collected from Crab Orchard and Little Grassy Lakes during April-May 2009 using AC electrofishing. Total length and weight were recorded and sagittal otoliths sectioned and aged by two readers. Increments between otolith annuli were measured and the Weisberg linear growth model was used to assess age and environmental (growth year) effects on individual growth for fish from the two lakes. Von Bertalanffy growth models indicated faster growth and a greater maximum total length for yellow bass in Little Grassy Lake. However, growth of fish in Little Grassy Lake nearly ceased after age 4. The Weisberg model indicated differences in individual growth rate between the two lakes that were consistent across years (age effects were significant but growth year effects and the age-growth year interaction were not). Inter-lake differences in fish growth were present up to age 3. Recruitment was relatively stable in Crab Orchard, with year classes up to age 7 observed. Recruitment was more erratic in Little Grassy, with age 5 being the dominant year class and fish up to age 11 present. Differences in growth and recruitment patterns for yellow bass in these two lakes may be attributed to substantial inter-lake differences in turbidity, morphoedaphic index, or yellow bass density. Maximum age of yellow bass (age 11) was higher than previously reported for this species, likely due to the use of otoliths to age fish rather than scales. This study provides baseline information on age and growth, mortality, recruitment, and size structure of yellow bass that can be compared to data from future studies to elucidate factors influencing population dynamics of this species

Using Pectoral Fin Rays as a Non-lethal Aging Structure for Smallmouth Bass: Precision with Otolith Age Estimates and the Importance of Reader Experience

We evaluated the potential utility of pectoral fin rays as non-lethal aging structures for smallmouth bass (Micropterus dolomieu). We compared age estimates among three reading pairs and against sectioned sagittal otolith age estimates for precision. Reading pair bias was not detected, although the highest rates of age estimate agreement occurred between reading pairs with high and moderate aging experience. Precision of otolith and fin ray age estimates were equivalent based on between-structure comparisons of average percent error and coefficient of variation. However, fin rays underestimated fish age compared to otoliths for older fish, especially when aged by less-experienced readers. Pectoral fin rays may provide a non-lethal alternative to otoliths for aging smallmouth bass, particularly for younger fish (≤age 4) or when experienced readers conduct aging. Additional evaluations of fin rays as smallmouth bass aging structures are needed, including validation using known-age fish and documentation of consistent annulus formation throughout a fish’s life

Long-Term PIT and T-Bar Anchor Tag Retention Rates in Adult Muskellunge

Mark-recapture studies require knowledge of tag retention rates specific to tag types, fish species and size, and study duration. We determined the probability of tag loss for passive integrated transponder (PIT) tags implanted into dorsal musculature, T-bar anchor tags attached to dorsal pterygiophores, and loss of both tags in relation to years post-tagging for double-marked adult muskellunge Esox masquinongy over a 10 year period. We also used PIT tags as a benchmark to assess the interactive effects of fish length at tagging, sex, and years post-tagging on T-bar anchor tag loss rates. Only five instances of PIT tag loss were identified; the calculated probability of a fish losing its PIT tag was consistently \u3c 1.0% for up to 10 years post-tagging. The probability of T-bar anchor tag loss by muskellunge was related to the number of years post-tagging and total length of fish at tagging. T-bar anchor tag loss rate one year after tagging was 6.5%. Individuals \u3c 750 mm total length at tagging had anchor tag loss rates \u3c 10% for up to 6 years after tagging. However, the proportion of fish losing T-bar anchor tags steadily increased with increasing years post-tagging (~30% after 6 years) for larger muskellunge. Fish gender did not influence probability of T-bar anchor tag loss. Our results indicate that T-bar anchor tags are best suited for short-term applications (≤ 1 year duration) involving adult muskellunge. We recommend use of PIT tags for longer-term tagging studies, particularly for muskellunge \u3e 750 mm total length

The Rewiring of Ubiquitination Targets in a Pathogenic Yeast Promotes Metabolic Flexibility, Host Colonization and Virulence

Funding: This work was funded by the European Research Council [http://erc.europa.eu/], AJPB (STRIFE Advanced Grant; C-2009-AdG-249793). The work was also supported by: the Wellcome Trust [www.wellcome.ac.uk], AJPB (080088, 097377); the UK Biotechnology and Biological Research Council [www.bbsrc.ac.uk], AJPB (BB/F00513X/1, BB/K017365/1); the CNPq-Brazil [http://cnpq.br], GMA (Science without Borders fellowship 202976/2014-9); and the National Centre for the Replacement, Refinement and Reduction of Animals in Research [www.nc3rs.org.uk], DMM (NC/K000306/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Acknowledgments We thank Dr. Elizabeth Johnson (Mycology Reference Laboratory, Bristol) for providing strains, and the Aberdeen Proteomics facility for the biotyping of S. cerevisiae clinical isolates, and to Euroscarf for providing S. cerevisiae strains and plasmids. We are grateful to our Microscopy Facility in the Institute of Medical Sciences for their expert help with the electron microscopy, and to our friends in the Aberdeen Fungal Group for insightful discussions.Peer reviewedPublisher PD

An evaluation Zequanox® efficacy and application strategies for targeted control of zebra mussels in shallow-water habitats in lakes

An evaluation of Zequanox® (a naturally derived biopesticide that is non-toxic to humans and other aquatic life and selectively kills dreissenid mussels) for controlling zebra mussel infestations in shallow-water habitats in lakes was conducted at Deep Quarry Lake in DuPage County, Illinois during summer 2012 and 2013. During the 2012 trial, three sets of paired 24-m² treatment and control sites were established within the lake, while a single 324-m² treatment site was established for the 2013 trial. Zequanox was applied to treatment plots, contained using PVC barrier curtains, and barriers were removed during the morning following application. Zebra mussel mortality and size distributions on natural substrates were assessed one day and one week post-treatment for 2012 trials and one day and two weeks posttreatment for 2013 trials; percent mortality of zebra mussels in mesh containers in treatment and control sites was also monitored up to 14 days and 48 days post-treatment in 2012 and 2013, respectively. Several water quality parameters were measured in control and treatment plots before and during application and up to 14 d post-treatment. Mean percent mortality for adult zebra mussels on natural and artificial substrates in treatment locations 7–48 d following Zequanox application ranged from 92–98% during both years, while mortality was consistently ≤10% in control locations. Mean percent mortality ranged from 15–76% in locations \u3e 5 m from and in water shallower than Zequanox application points (\u3c0.6 m depth) during the 2013 trial likely due to limited product dispersal into these areas. There was no significant difference in the size distribution of live and dead zebra mussels in treatment plots. Mean veliger mortality was 94.4% 20-h after the start of the 6-h Zequanox treatment period in the treatment area compared to 15.1% in untreated locations during the 2013 trial. Temporary but substantial reductions in dissolved oxygen were observed in treatment locations during the morning following Zequanox treatment in both 2012 and 2013 trials, likely due to the presence of the barriers that prevented well-oxygenated water from circulating into treatment zones from adjacent areas in the lake. Dissolved oxygen concentrations quickly rebounded to levels consistent with control sites upon removal of barriers. No effects of Zequanox treatment on ammonia, total nitrogen, total phosphorus, biochemical oxygen demand, chlorophyll a, pH, or conductivity were observed. Results suggest that Zequanox has potential as a tool for controlling zebra mussels in shallow-water habitats in lakes without significant long-term effects on water quality