Walleyes Stizostedion vitreum vitreum and white suckers Catostomus commersoni shared a common spawning ground in Apsley Creek. Their reproduction overlapped in time, but white suckers spawned mainly in the riffle zone (710 eggs/m 2) and rarely in quiet water (0.5 eggs/ m 2) surrounding the riffle. In contrast, walleyes spawned more in quiet water (6,241 eggs/m :) than in the riffle (65 eggs/m:). Walleye egg survival was higher on a sand-gravel-rock substrate than it was on a mud-detritus bottom. Spottail shiners Notropis hudsonius and yellow perch Perca fiavescens fed extensively on walleye eggs; predation on white sucker eggs was not detected. Larva drift of both species was passive, varying with stream velocity, and occurred during periods of decreasing light (2100-0100 hours). Although eggs of both species began hatching on May 7, white sucker larvae drifted 11-13 d after walleye larvae. There was no indication that walleyes and white suckers competed for spawning areas as adults or for food as larvae.

Many species of fishes along the east coast of the United States have complex life histories, especially those that move over hundreds of kilometers across ocean and estuarine habitats. To further unravel the life history of one of these, the speckled worm eel, Myrophis punctatus we examined samples from extensive time series and discrete samples collected in the ocean and estuaries between Florida and Massachusetts. We now surmise spawning occurs between fall and early winter in the ocean south of Cape Hatteras, North Carolina and in the vicinity of the Bahamas. The pelagic leptocephalus larvae (10-80 mm Total Length [TL]) are transported north in the Gulf Stream and across the continental shelf to arrive at estuarine inlets at ages of 53 -110 days. Their estuarine immigration and abundance varies along the east coast, with higher levels occurring at inlets in South Carolina (North Inlet), and North Carolina (Beaufort Inlet), during the winter and early spring. Much lower abundances occur in New Jersey (Little Egg Inlet) in winter and spring and again in the summer. These ingressing individuals were euryodontic leptocephali and metamorphic stages and were shrinking to lengths of 76-52 mm TL as these stages progressed. Metamorphic individuals and glass eels subsequently settle and burrow in estuarine sediments, as do all subsequent stages, and thereby become relatively unavailable to many sampling gears. In estuaries they Environ Biol Fish (2011) 92:237-259

Light traps were used to assess larval abundance and chronology of appearance in Chemung Lake in 1982. Eleven of 21 resident species were captured, totalling 7234 individuals. The most abundant were yellow perch (2809), Iowa darter (2571), pumpkinseed sunfish (1288), bluntnose minnow (200), and carp (123). Iowa darter and pumpkinseed were taken only as prolarvae (yolk-sac larvae) and postlarvae, but yellow perch, from 5 to 33 mm total length, were attracted. Common carp and bluntnose minnow entered traps almost exclusively as prolarvae (6–13 mm and 6–12 mm total length, respectively). Perch had the shortest emergence period, May 6–12 (15–17 °C), followed by darters. May 9–31 (15–21 °C). Pumpkinseed and carp emerged over a 6-week period from June 3 to July 23 (16–25 °C). Perch prolarvae preferred shallow, high-density macrophyte areas; their postlarvae preferred deep, low-density macrophyte zones. All stages of larval darter selected shallow, macrophyte-dense regions, as did the young of pumpkinseed.

Several basic tenets of otolith research have been questioned recently with regard to eel metamorphosis. Specifically, some researchers have suggested that otolith increment formation is not daily, and otolith material may be resorped during metamorphosis. We conducted a rearing experiment to test the hypothesis that increment formation is daily and that the otolith continues to grow during eel metamorphosis. We marked the otoliths of wild-caught Myrophis punctatus leptocephali and reared these fish through metamorphosis. Metamorphosis was characterized by a decreasing standard length, pre-anal length, and body depth accompanied by an increase in pigmentation and a change in behavior. Increment formation was daily or near-daily through metamorphosis, and the otolith continued to grow during metamorphosis. Thus, the basic tenets of otolith application apply to eel metamorphosis, and non-daily ring deposition and resorption should not be used as explanations for otolith characteristics of eels (e.g., back-calculated hatch dates) unless demonstrated experimentally.

SynopsisThe emergence chronology of brook charr alevins in the Chikanishing River, Ontario, Canada and the concurrent changes in stream chemistry resulting from acidic snowmelt runoff were examined during the spring, 1986-1988. Emergence patterns were similar among years with the most intense emergence (> 70%) occurring during the declining stream discharge following the spring flood. This period coincided with stream pH depressions (minimum pH5.2) in 2 of 3 years, suggesting emergence behaviour frequently subjects the earliest free-swimming life interval of brook charr to episodic acidification events.