Managing Centrarchid Fisheries in Rivers and Streams

<em>Abstract.</em>—Unique genetic lineages of <em> Micropterus </em>species are increasingly recognized; however, little effort has been devoted to identifying their ecological relationships despite recognition of their conservation value by management agencies. Our study objectives were to determine young-of-year, first-summer survival, and examine overall channel-unit habitat use by the Neosho subspecies of Smallmouth Bass <em> Micropterus dolomieu velox </em>from two Ozark streams (Spring and Buffalo creeks). We completed snorkel surveys approximately every 2 weeks from June–September 2013. As anticipated, young-of-year mortality was high during the first 2 weeks of the sampling period (85% in Buffalo Creek and 99% in Spring Creek). Mortality stabilized by the end of July in both streams and was similar over subsequent 2-week periods (95% CI: 0.13%–2.38% and 0.72%–3.48%, in Spring Creek and Buffalo Creek, respectively). In Spring Creek, backwater habitats were unavailable, and young-of-year fish used both pool and run habitats throughout the study duration. However, we observed different habitat-use patterns in Buffalo Creek: young-of-year fish used pools and backwaters throughout the season, use of run habitats increased by late July, and increased use of backwater habitats followed an increase in late summer discharge. In general, there was substantial habitat use variability both within and between streams. Considering both stream reaches combined, young-of-year fish densities in riffle habitat were statistically lower than other channel units. We show that young-of-year Neosho Smallmouth Bass mortality is high during the first few weeks following swim up, and that backwater habitats may be important to early life stages under certain environmental conditions.

2016 ◽  
Vol 73 (9) ◽  
pp. 1330-1341 ◽  
Author(s):  
William W. Fetzer ◽  
Collin J. Farrell ◽  
James R. Jackson ◽  
Lars G. Rudstam

Walleye (Sander vitreus), smallmouth bass (Micropterus dolomieu), and largemouth bass (Micropterus salmoides) are common top predators across many north temperate lakes, but no previous analyses have assessed factors driving their combined impact on mortality of a shared prey, yellow perch (Perca flavescens). We estimated consumption dynamics of walleye, smallmouth bass, and largemouth bass during 3 years that differed in age-0 yellow perch year-class strength and evaluated the relative contribution of each predator to age-0 yellow perch mortality, in Oneida Lake, New York, USA. Habitat-specific diet composition and population densities were integrated with temperature and growth rates to parameterize a bioenergetics model and estimate annual consumption of major diet items. Walleye were the dominant predator in both offshore and inshore habitats, while smallmouth bass and largemouth bass were also important inshore predators. Consumption of age-0 yellow perch by all three predators was positively correlated to age-0 yellow perch year-class strength, but our ability to account for age-0 yellow perch mortality decreased during years when year-class strength was strong. Within each year, predation by the three species accounted for all observed age-0 yellow perch mortality in late summer and fall, but not in the early summer, suggesting other predators in the lake likely predate on the youngest, most vulnerable yellow perch. These results are important for understanding how diverse predator communities can alter the spatial and temporal availability of prey refuges and influence mortality of a shared prey.


2017 ◽  
Vol 23 (10) ◽  
pp. 4045-4057 ◽  
Author(s):  
Ross E. Boucek ◽  
Michael R. Heithaus ◽  
Rolando Santos ◽  
Philip Stevens ◽  
Jennifer S. Rehage

Author(s):  
Daniel Danilewicz ◽  
Eduardo R. Secchi ◽  
Paulo H. Ott ◽  
Ignacio B. Moreno ◽  
Manuela Bassoi ◽  
...  

The patterns of habitat use by the franciscana dolphins (Pontoporia blainvillei) along its distribution are poorly known. This study investigates the patterns of habitat use with respect to depth for 181 individuals of different age, size, gender and reproductive condition off Rio Grande do Sul, southern Brazil. The results reveal that franciscanas are very homogeneously distributed according to depth. Individuals from all lengths utilize nearly the entire range of depths of the surveyed area. Larger or older animals do not use deeper waters than younger animals, indicating that body size and age are not limiting factors for franciscanas that occupy deeper or offshore waters. Gestation seems to not cause a change in the distribution of females. Although the sex-ratio of the overall data did not vary from 1:1 in different depth intervals, a small-scale comparison between the northern and southern coast demonstrated the existence of some kind of sexual segregation. Franciscana by-catch in Rio Grande do Sul is not sustainable and it is agreed that management procedures are needed. Nevertheless, the available data on species distribution do not allow the designing of a protected area in order to minimize the by-catches of a particular sex/reproductive class.


2018 ◽  
Vol 75 (12) ◽  
pp. 2343-2353 ◽  
Author(s):  
Ingeborg M. Mulder ◽  
Corey J. Morris ◽  
J. Brian Dempson ◽  
Ian A. Fleming ◽  
Michael Power

Anadromous Arctic char (Salvelinus alpinus) migrate back to fresh water in late summer to spawn and (or) overwinter. Upon freshwater entry, feeding is reduced or absent, and movement activity is restricted. While the physiological responses to low temperatures (e.g., growth, metabolism) are understood, specifics of the use of thermal habitat for overwintering remains poorly characterized. This study used acoustic and archival telemetry data from two lakes in southern Labrador, Canada, to study thermal habitat use during the ice-covered period. Results showed that lake-dwelling anadromous Arctic char predominantly occupied a narrow range of temperatures (0.5–2 °C) and used cooler temperatures available within the middle and upper water column. Use of the selected temperatures is likely a strategy that lowers metabolic costs and minimizes energy expenditure, preserving stored lipids for overwinter survival and the energetic costs of preparation for seaward migration. As Arctic char are visual feeders, use of the upper water column is also thought to aid foraging efficiency by increasing the likelihood of prey capture.


2019 ◽  
Vol 39 (2) ◽  
pp. 240-253
Author(s):  
Andrew D. Miller ◽  
Robert Mollenhauer ◽  
Shannon K. Brewer

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