Mercury (Hg) trophic transfer and bioaccumulation in fish from a mine-impacted, eutrophic lake were examined in relation to foraging habitat, trophic position, and size. Diet analysis indicated that there were clear ontogenetic shifts in foraging habitats and trophic position. Pelagic diet decreased and benthic diet increased with increasing fish length in bluegill, black crappie, inland silver...

The possible occurrence of a functional ornithine-urea cycle (OUC) and changes of activity of key amino acid metabolism-related enzymes were studied in the amphihaline shad hilsa (Tenualosa ilisha) that were collected from estuarine water of Kakdwip and from freshwater river basin of Bhrahmaputra during the breeding season. Very high concentration of urea was detected in different tissues and p...

Anchovies, salmon, sardines, gobies, mullets, flounder, bass, barbels, eels, shad, and even sharks—what do they have in common? Well, at certain points their lives you may find them estuaries, the final sections of rivers before meet ocean. Some fish live estuaries entire lives. However, some species prefer living freshwater parts others only close to ocean, a few spread throughout estuary. bot...

Ahstn1~~-Pnssngc and trnnsit time of ndult upstream-migrant Amcricnn shnd Alosu sapidissima ~ n d blucback hcrring A. ucstivalls wcrc investigated in standard Dcnil and Alnska stecppass fishways with vnrinhlc slopc and hcndpond undcr scmicontrollcd condition^. Percent of Amcricnn hhad passcd per unit time (percent pnssnge) incrcnsed with temperature, while time required to lrom the lishway entr...

Effects of gizzard shad Dorosoma cepedianum on benthic communities in a large southern reservoir (Lake Texoma, U.S.A.) were examined during two field enclosure and exclosure experiments in which enclosures were stocked at high and low densities in 1998 and 1999, respectively. In both years, chironomid abundance significantly increased in treatments that excluded large fishes from foraging on se...

The relationship between the Lower Danube River level and Romanian annual catches of Pontic shad (Alosa immaculata, Bennett 1835) were analyzed. For analysis of long term data on the Danube River water level and Pontic shad catch, combinations of different methods were applied using statistical programs, SPSS 13.0 and MATLAB 6. Periodograms, containing cyclic patterns, were obtained using Fouri...

—We developed and applied a stable isotope turnover model to estimate how long age-0 American shad Alosa sapidissima reside within tidal freshwater and brackish-water habitats in the York River estuary, Virginia. The residence time was estimated by modeling the changing stable isotope ratio (either the carbon [dC] or sulfur [dS] stable isotope ratio) of an age-0 American shad as it migrates sea...

Studies that span entire species ranges can provide insight into the relative roles of historical contingency and contemporary factors that influence population structure and can reveal patterns of genetic variation that might otherwise go undetected. American shad is a wide ranging anadromous clupeid fish that exhibits variation in demographic histories and reproductive strategies (both semelp...

− The application of fisheries acoustics in shallow waters opens new fields of observation and allows new methods for abundance estimates. In this paper we deal with echocounting of migrating fish crossing the Beaucaire-Vallabrègues lock, the first obstacle encountered on the Rhône, using a SIMRAD EY500 split-beam sounder, 70 kHz frequency. Two transducers sampled a section of water and evaluat...

This study examined mercury concentrations in whole fish from Camp Far West Reservoir, an 830-ha reservoir in northern California, USA, located downstream from lands mined for gold during and following the Gold Rush of 1848-1864. Total mercury (reported as dry weight concentrations) was highest in spotted bass (mean, 0.93 microg/g; range, 0.16-4.41 microg/g) and lower in bluegill (mean, 0.45 mi...