Assessment of Otolith Chemistry as an Indicator of Fish Movement or Transfer Between the Illinois River System and Lake Michigan

Naturally occurring chemical markers in otoliths offer a potential means to identify source environment for fishes in the upper Illinois River system and Lake Michigan, including individuals that may breach electrical barriers in the Chicago Sanitary and Ship Canal or be transferred via bait buckets between these formerly isolated drainages. The objectives of this study were to determine whether water and fish otolith stable isotopic and elemental compositions differ among Lake Michigan, the upper Illinois River, and three tributaries of the upper Illinois River (Fox, Des Plaines and DuPage Rivers) and to determine whether otolith isotopic and elemental signatures could be used to identify the water body from which individual fish were collected. Water and fish otolith samples were obtained from each site during summer 2007 and analyzed for δ18O and a suite of trace element concentrations; otoliths were also analyzed for δ13C. Otolith δ13C values for Lake Michigan fish were distinct from individuals collected in the Illinois River and tributaries. Fish collected in the Fox and Des Plaines Rivers could be distinguished from one another and from fish captured in the Illinois and DuPage Rivers using otolith Sr:Ca and Ba:Ca ratios. Otoliths reflected differences in water Sr:Ca and Ba:Ca among environments. Otolith isotopic and elemental compositions may enable determination of source environment for any Asian carp discovered in Lake Michigan and could also be useful as indicators of environmental history for fishes in the upper Illinois River and its tributaries

Pan-Arctic distribution of bioavailable dissolved organic matter and linkages with productivity in ocean margins

Rapid environmental changes in the Arctic Ocean affect plankton productivity and the bioavailability of dissolved organic matter (DOM) that supports microbial food webs. We report concentrations of dissolved organic carbon (DOC) and yields of amino acids (indicators of labile DOM) in surface waters across major Arctic margins. Concentrations of DOC and bioavailability of DOM showed large pan-Arctic variability that corresponded to varying hydrological conditions and ecosystem productivity, respectively. Widespread hot spots of labile DOM were observed over productive inflow shelves (Chukchi and Barents Seas), in contrast to oligotrophic interior margins (Kara, Laptev, East Siberian, and Beaufort Seas). Amino acid yields in outflow gateways (Canadian Archipelago and Baffin Bay) indicated the prevalence of semilabile DOM in sea ice covered regions and sporadic production of labile DOM in ice-free waters. Comparing these observations with surface circulation patterns indicated varying shelf subsidies of bioavailable DOM to Arctic deep basins.Published version2019-07-3

Evaluation of a Stable Isotope Labeling Technique for Mass-Marking Fin Rays of Age-0 Lake Sturgeon

The effectiveness of marking age-0 lake sturgeon, Acipenser fulvescens Rafinesque, pectoral fin rays with a stable strontium isotope was evaluated. Age-0 lake sturgeon were reared in water spiked with 0 (control), 25, 50, or 100 μg L-1 86SrC03 for 10 and 24 d; fish from each treatment group were retained for up to 120 d post-labeling to assess mark retention. Enriched isotope marks imparted to fin rays were distinct from fin ray 88Sr/86Sr ratios of control fish immediately following marking, with the 100 μg L-1 86SrCO3 treatments consistently yielding the highest rate of marking success (83-92%). Lower marking success (25-69%) was observed with the 25 and 50 μg L-1 86SrCO3 treatments. Isotopic marks in fin rays were retained for 120 d post-labeling. Immersion marking of juvenile fish pectoral fin rays with distinct strontium isotope ratios is possible and does not require sacrificing fish to check for marks

Research report : enhanced hydrographic survey for CPL discharge in Nueces Bay

The objectives of the enhanced hydrographic survey in Nueces were: A. to monitor the vertical and horizontal distributions of temperature and salinity, nutrients and plant pigments in the nearby area of the CPL cooling water discharge channel in Nueces Bay. B. to compare the distributions of the above parameters to those throughout other portions of Nueces Bay during freshwater release and non-release periodsFor Central Power and Light Company ... Corpus Christi, Texas ...November 1993Marine Scienc

Habitat Associations of Fish Assemblages in the Cache River, Illinois

Fish and habitat were sampled by state agencies at 48 stations throughout the Cache River watershed, Illinois between 1992 and 2009. Two distinct fish assemblages were identified, one primarily found in the lower mainstem Cache River and a second found throughout tributaries and the upper mainstem Cache River. Using a canonical correspondence analysis, the distribution of fish species was largely explained by substrate, land use, drainage area and local habitat features. Creek chub, central stoneroller, fringed darter and fantail darter are species found to be positively associated with gravel substrate and forest. In contrast, black buffalo, gizzard shad, smallmouth buffalo, freshwater drum and bigmouth buffalo were positively associated with drainage area, silt, channel width and row crops. Cobble appears to be rare habitat associated with fringed darter, freckled madtom and fantail darter. Results suggest that substrate, land use and local habitat features influence fish assemblages within the Cache River watershed. This information contributes to both understanding aquatic community structure in a highly altered yet diverse watershed as well as management activities within the Cache River watershed

Fatty Acid Profiles Distinguish Channel Catfish From Three Reaches of the Lower Kaskaskia River and its Floodplain Lakes

Despite the increasing use of fatty acids (FAs) as biomarkers in aquatic food web analysis, little information is available regarding differences in FA profiles of fish among habitat types in river-floodplain ecosystems. The objectives of this study were to 1) test whether the FA profiles of channel catfish (Ictalurus punctatus) differed among three reaches of the lower Kaskaskia River and its floodplain lakes, and 2) to compare FA profiles among muscle, liver, and adipose fin tissues collected from these fish. Profiles differed significantly among sites, especially between upper and lower river sites, and between river channel and oxbow lake sites, suggesting differences in FA availability for channel catfish occupying different habitats and river reaches in the Kaskaskia River system. Specifically, the essential FAs 18:2n-6 and 18:3n-3 increased in catfish tissues from upstream to downstream reaches, which could reflect increased floodplain connectivity and decreasing impoundment effects downstream. Ratios of n-3 to n-6 FAs were higher in fish from oxbow lakes, perhaps suggesting increased use of autochthonous production in the floodplain relative to the main river channel. Muscle and adipose fin FA profiles exhibited similar location-related trends, whereas liver FA profiles were markedly different from the other tissue types. These results suggest that adipose fin tissue samples may be a viable, less-invasive alternative to muscle tissue for analysis of FA profiles in channel catfish. Our study supports the use of tissue FA profiles in identifying habitat utilization by channel catfish, and perhaps habitat-specific energy contributions to riverine consumers. Furthermore, our work highlights floodplain habitat as a potential source of essential n-3 FA and the associated importance of maintaining river-floodplain connectivity to support aquatic food webs

Trace element and Stable Isotopic Signatures in Otoliths and Pectoral spines as Potential Indicators of Catfish Environmental History

Natural chemical markers in otoliths and fin rays have proven useful for retrospectively describing environmental history of fishes in a variety of environments. However, no studies have applied this technique to catfishes or evaluated catfish pectoral spine chemistry as a nonlethal alternative to otolith chemistry. We characterized relationships between water, otolith, and pectoral spine (articulating process) chemistry for channel catfish Ictalurus punctatus, flathead catfish Pylodictis olivaris, and blue catfish I. furcatus and determined the accuracy with which fish could be classified to their environment of capture using otolith and pectoral spine chemical signatures. Fish and water samples were collected from nine sites during 2009. Otolith, spine, and water samples were analyzed for Sr:Ca and Ba:Ca; otolith δ18O and δ13C and water δ18O were also measured. Water, otolith, and spine Sr:Ca were highly correlated, as were water and otolith δ18O. Relationships between water, otolith, and spine chemistry did not differ among species. Otolith Sr:Ca, δ18O, and δ13C and spine Sr:Ca differed among sites, reflecting geographic differences in water chemistry. Neither otolith nor spine Ba:Ca differed among sites despite inter-site differences in water Ba:Ca. Both otolith Sr:Ca, δ18O, and δ13C and fin spine Sr:Ca classified fish to their environment of capture with a high degree of accuracy, except in the middle and lower Mississippi River where many recent immigrants appeared to be present. Natural chemical signatures in otoliths or pectoral spines will likely be effective for reconstructing environmental history of catfishes when spatial differences in water chemistry are present, enabling investigations of stock mixing and recruitment sources for these species

Fin Ray Chemistry as a Potential Natural Tag for Smallmouth Bass in Northern Illinois Rivers

Natural chemical markers in otoliths and fin rays have proven useful for describing environmental history of fishes in a variety of environments. However, no studies have evaluated smallmouth bass (Micropterus dolomieu) pectoral fin ray chemistry as a non-lethal alternative to otolith chemistry. We evaluated the trace element composition of smallmouth bass fin rays collected from northern Illinois rivers and determined the accuracy with which fish could be classified to their environment of capture using pectoral fin ray strontium:calcium (Sr:Ca) and barium:calcium (Ba:Ca) ratios. Fish were collected from nine sites during summer 2008. Fin ray Sr:Ca differed among some sites, reflecting previously observed differences in water and otolith chemistry for other fish species. Fin ray Ba:Ca did not differ among sites. Classification accuracy for individual fish to location of capture based on fin ray Sr:Ca was relatively poor when data from all nine sites in different watersheds were included. However, individual fish captured from the upper Illinois River watershed were accurately assigned to the river in which they were collected when data were restricted to these sites. Natural chemical signatures in fin rays will likely be effective for reconstructing environmental history of smallmouth bass when spatial differences in water chemistry are present, enabling investigations of stock mixing and recruitment sources for this species