Determining the factors that influence recruitment to sequential ontogenetic stages is critical for understanding recruitment dynamics of fish and for effective management of sportfish, particularly in dynamic and unpredictable environments. We sampled walleye (Sander vitreus) and white bass (Morone chrysops) at 3 ontogenetic stages (age 0 during spring: ‘age-0 larval’; age 0 during autumn: ‘ag...

Four species of pelagic fish of particular management concern in the upper San Francisco Estuary, California, USA, have declined precipitously since ca. 2002: delta smelt (Hypomesus transpacificus), longfin smelt (Spirinchus thaleichthys), striped bass (Morone saxatilis), and threadfin shad (Dorosoma petenense). The estuary has been monitored since the late 1960s with extensive collection of da...

American shad ( Alosa sapidissima ) are native to the east coast of North America from St. Johns River, Florida, Lawrence River region in Canada. Since 1800s, dams have reduced access spawning habitat. To assess impact dams, we estimated historically accessed habitat coastal rivers (485,618 river segments with 21,113 current dams) based on (i) width, (ii) distance seawater, and (iii) slope (to ...

Toothed whales and bats have independently evolved biosonar systems to navigate and locate and catch prey. Such active sensing allows them to operate in darkness, but with the potential cost of warning prey by the emission of intense ultrasonic signals. At least six orders of nocturnal insects have independently evolved ears sensitive to ultrasound and exhibit evasive maneuvers when exposed to ...

discovered that certain fish are also sensitive to ultrasound. Cod may be able to detect echolocating odontocetes at 10–30 metres, and shad may detect their main predators, dolphins, at a range of 180 metres. Blueback herring swim away from echosounders used to survey them, raising the possibility that fish may exhibit negative phonotactic behaviour in the way that moths do. Some clupeid fish e...

—We analyzed data on spring and summertime larval and juvenile fish distribution and abundance in the upper San Francisco Estuary (SFE), California between 1995 and 2001. The upper SFE includes the tidal freshwater areas of the Sacramento–San Joaquin Delta downstream to the euryhaline environment of San Pablo Bay. The sampling period included years with a variety of outflow conditions. Fifty ta...

We examined trends in abundance of four pelagic fish species (delta smelt, longfin smelt, striped bass, and threadfin shad) in the upper San Francisco Estuary, California, USA, over 40 years using Bayesian change point models. Change point models identify times of abrupt or unusual changes in absolute abundance (step changes) or in rates of change in abundance (trend changes). We coupled Bayesi...

Department of Natural Resources. The form and content of this report and the interpretations of the data are the responsibility of the University of Illinois and the Illinois Natural History Survey and not the Illinois Department of Natural Resources. References Tables Figures Evaluation of muskellunge and tiger muskellunge stocking program. Executive Summary Size specific survival of muskellun...