نتایج جستجو برای: perch
تعداد نتایج: 1712 فیلتر نتایج به سال:
Larval dispersal is a crucial factor for fish recruitment. For fishes with relatively small-bodied larvae, drift has the potential to play a more important role than active habitat selection in determining larval dispersal; therefore, we expect small-bodied fish larvae to be poorly associated with habitat characteristics. To test this hypothesis, we used as model yellow perch (Perca flavescens)...
To explore the distribution of Pfiesteria piscicida in Korean coastal waters, we analyzed the morphology and DNA sequence of several isolates collected from 6 locations along the southern and western Korean coasts. We also investigated the prey species consumed by a Korean isolate and determined the growth and ingestion rates of P. piscicida when it fed on the dinoflagellate Amphidinium cartera...
A bow-mounted surface pushnet and an obliquely towed plankton net were compared to evaluate gear efficiency and effectiveness in collecting larval fishes under daytime and nighttime conditions. The diadromous species targeted were striped bass Morone saxatilis, white perch, Morone americana, and river herring Alosa sp. We sampled the lower Roanoke River, North Carolina, from March through June ...
This study investigated ion regulation in relation to water pH in three species of fish of differing tolerance to low pH (common shiners, Notropis cornutus, most sensitive; rainbow trout, Salmo gairdneri, intermediate; yellow perch, Perca flavescens, least sensitive). Increasing sensitivity to exposure to low pH was characterized by shorter survival times, greater losses of whole-body ions, mor...
Background. Variable adherence to standardized case definitions, clinical procedures, specimen collection techniques, and laboratory methods has complicated the interpretation of previous multicenter pneumonia etiology studies. To circumvent these problems, a program of clinical standardization was embedded in the Pneumonia Etiology Research for Child Health (PERCH) study. Methods. Between Ma...
We describe for the first time reproductive behaviors in the Pirate Perch (Aphredoderus sayanus), a secretive nocturnal fish whose urogenital opening is positioned far anteriorally, under its throat. Some naturalists had speculated that this peculiar morphological condition might serve to promote egg transfer to the fish’s branchial chamber for gill-brooding; others hypothesized that Pirate Per...
Many insects rely on chemical signals to transmit precise information on the location, identity, and quality of potential mates. Chemical signals are often broadcasted at sites with physical properties that maximize signal propagation and signal transmission. Male neotropical orchid bees (Euglossini) perch and display on vertical branches and tree trunks in the forest to expose volatile blends ...
Climate change is expected to affect fish populations worldwide through a number of mechanisms. To help understand consistent, failed Lake Erie yellow perch (Perca flavescens) year-classes following warm winters during 1975–2010, we used a combined laboratory-experimental and population-modeling approach. We hypothesized that climate change would negatively affect yellow perch by 1) increasing ...
Color is one of the perch properties. This study was conducted to investigate the general behaviors and perching behaviors in laying hens under different group size (stocking density), and to understand the perch color (black, white or brown) preference of hens during the night. A total of 390 Hyline Brown laying hens was used, and randomly allocated to three treatments: individual group (G1), ...
The impact of young-of-the-year (YOY) fish predation on zooplankton dynamics and cascading effects down to phytoplankton were studied in lake enclosures using different densities of larval and juvenile European perch (Perca fluviatilis). Two experiments, one in June and one in August, were performed in Lake Dagstorpssjön, a slightly eutrophic lake in Scania, southern Sweden. In our experiments,...
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