Piscivority in a Land-Locked Alewife (Alosa pseudoharengus) Population

1980 ◽  
Vol 37 (8) ◽  
pp. 1314-1317 ◽  
Author(s):  
Christopher C. Kohler ◽  
John J. Ney

Larval fish were a frequent dietary component of alewives (Alosa pseudoharengus) from Claytor Lake, Virginia, USA. Alewives consumed the young of four game and two forage species (maximum 26 mm total length (TL)). Alewife piscivority appeared to be at least partially nocturnal and was more prominent in littoral than in limnetic areas. Predator and prey lengths were positively correlated, although morphological limits on larval fish ingestion by alewives were not severe. Peak occurrence (40–70%, June 1978) of larval fish in alewife stomachs coincided with a precipitous decline in zooplankton density. Zooplankton abundance was higher in early summer 1979, when alewife piscivority was less common. Our findings support the hypothesis that alewife piscivority could have contributed to the collapse of Great Lakes resident fish populations following alewife establishment. Alewife piscivority should be considered in risk–benefit evaluations prior to introducing alewife as a pelagic forage species.Key words: alewife, Alosa pseudoharengus; feeding ecology, larval fish, Great Lakes fisheries, forage introductions

2010 ◽  
Vol 1 (2) ◽  
pp. 73-85 ◽  
Author(s):  
Jeffrey C. Jolley ◽  
David W. Willis ◽  
Richard S. Holland

Abstract Food availability may regulate fish recruitment, both directly and indirectly. The availability of zooplankton, especially to newly hatched larvae, is thought to be crucial to their early growth and survival. We examined stomach contents of larval bluegill Lepomis macrochirus and yellow perch Perca flavescens in Pelican Lake and Cameron Lake, Nebraska, in 2004 and 2005. We also determined zooplankton availability and calculated prey selection using Chesson's α. In addition, we investigated potential match–mismatch regulation of recruitment from 2004 to 2008. Bluegill positively selected copepod nauplii and Bosmina spp., and yellow perch often selected copepods. Abundant zooplankton populations were available for consumption. Matches of both larval bluegill and yellow perch abundance to zooplankton abundance were detected in all years; exact matches were common. Mismatches in predator and prey production were not observed. Predation by age-0 yellow perch on age-0 bluegill was not observed, even though yellow perch hatched 2 mo prior to bluegill. Given that zooplankton were abundant and well-timed to larval fish relative abundance over the time span of this study, the match–mismatch hypothesis alone may not fully account for observed recruitment variability in these populations. Environmental conditions may also affect recruitment and warrant further investigation.


Abstract.—Burbot <em>Lota lota </em>populations collapsed in four of the five Laurentian Great Lakes between 1930 and the early 1960s. Collapses in Lakes Michigan, Huron, and Ontario were associated with sea lamprey <em>Petromyzon marinus </em>predation, whereas the collapse in Lake Erie was likely due to a combination of overexploitation, decreased water quality, and habitat degradation. We examined time series for burbot population density in all five lakes extending as far back as the early 1970s to present time and characterized the long-term trends after the initial collapses. Burbot population density in Lake Superior has remained relatively low and stable since 1978. Recovery of the burbot populations occurred in Lakes Michigan and Huron during the 1980s and in Lake Erie during the 1990s. Control of sea lampreys was a requirement for recovery of burbot populations in these three lakes. Declines in alewife <em>Alosa pseudoharengus </em>abundance appeared to be a second requirement for burbot recovery in Lakes Michigan and Huron. Alewives have been implicated in the decline of certain Great Lakes fish stocks that have pelagic larvae (e.g., burbot) by consuming the pelagic fry and possibly by outcompeting the fry for food. Relatively high populations of adult lake trout <em>Salvelinus namaycush </em>compared to burbot served as a buffer against predation by sea lampreys in Lakes Huron and Erie, which facilitated recovery of the burbot populations there. Although sea lampreys have been controlled in Lake Ontario, alewives are probably still too abundant to permit burbot recovery.


<em>Abstract</em>.—Thiamine concentrations in representative Great Lakes prey fish, including alewives <em>Alosa pseudoharengus</em>, rainbow smelt <em>Osmerus mordax</em>, slimy sculpin <em>Cottus cognatus</em>, bloater chub <em>Coregonus hoyi</em>, and lake herring <em>Coregonus artedi</em>, and their major dietary items, including mysids <em>Mysis relicta</em>, amphipods <em>Diporeia hoyi</em>, and net macroplankton, were measured to assess their potential involvement in depressed thiamine concentrations in lake trout <em>Salvelinus namaycush </em>of the Great Lakes. Mean thiamine concentrations in all biota were greater than the recommended dietary intake of 3.3 nmol/g for prevention of effects on growth, although the adequacy of these concentrations for reproduction is not known. Mean thiamine concentrations decreased in the order alewives > bloater chub, herring > smelt and differed from the order of associated egg thiamine concentrations published for lake trout feeding on these species (herring > alewives, smelt). As a result, these data strongly implicate the high thiaminase content, rather than the low thiamine content, of alewives and smelt as being responsible for the low egg thiamine concentrations of Great Lakes lake trout stocks that feed heavily on these species. Variations in thiamine content among prey species did not appear to be related to levels in their diet, because thiamine concentrations in <em>Mysis</em>, <em>Diporeia</em>, and macroplankton showed little consistency between group or between lake variation. There was no lake to lake variation in mean thiamine concentrations of prey species, but considerable within species variation occurred that was unrelated to size.


2010 ◽  
Vol 67 (9) ◽  
pp. 1903-1913 ◽  
Author(s):  
Jacob F. Schweigert ◽  
Jennifer L. Boldt ◽  
Linnea Flostrand ◽  
Jaclyn S. Cleary

AbstractSchweigert, J. F., Boldt, J. L., Flostrand, L., and Cleary, J. S. 2010. A review of factors limiting recovery of Pacific herring stocks in Canada. – ICES Journal of Marine Science, 67: 1903–1913. On the west coast of Canada, Pacific herring (Clupea pallasi) supported an intensive reduction fishery from the early 1930s until the collapse of all five major stocks in the late 1960s, which then recovered rapidly following a fishery closure. Despite conservative harvests, abundance has declined again recently, with little evidence of recovery. We investigated the effect of bottom-up forcing by zooplankton abundance, top-down forcing by fish and mammal predators, and the effects of sardine abundance as potential competitors on the natural mortality of the herring stock on the west coast of Vancouver Island. Herring mortality was positively related to Thysanoessa spinifera and southern chaetognaths and negatively to pteropod abundance. Estimated predation on herring decreased significantly during the years 1973–2008, with the main consumers changing from fish to mammals. However, the correlation with herring mortality was negative, whereas there was a significant positive relationship with sardine abundance. Population recovery is expected to be facilitated by a combination of factors, including adequate food supply, limited or reduced predation (including fishing), and limited competition particularly for wasp–waist systems, where different forage species may occupy similar niches.


2020 ◽  
Vol 13 (10) ◽  
pp. 2630-2645
Author(s):  
Shelby E. Smith ◽  
Eric P. Palkovacs ◽  
Brian C. Weidel ◽  
David B. Bunnell ◽  
Andrew W. Jones ◽  
...  

1987 ◽  
Vol 14 (1) ◽  
pp. 35 ◽  
Author(s):  
DC Cheal

The diets of Rattus fuscipes and R. lutreolus from a site in central southern Victoria were investigated by faecal analysis. R. lutreolus was predominantly herbivorous; in heath it selected the basal stems of certain cyperaceous herbs, and in forest it ate non-sclerophyllous grasses. Fungi were an important dietary component and seed might be eaten in some quantity for a short time in spring and early summer. R. fuscipes showed little dietary overlap with R. lutreolus; in forest it was reliant on fungi and fibrous plant material from particular grasses; in heath it relied on particular cyperaceous species in winter, and ate primarily fleshy fruit, seed and arthropods in summer. Dietary preferences are compared with the relative abundance of diet items in the habitat. Both species are selective, and this selectivity changes with season. The effects of the availability of preferred diet items on the species' distributions are discussed.


1994 ◽  
Vol 39 (8) ◽  
pp. 1790-1799 ◽  
Author(s):  
Brian R. MacKenzie ◽  
Thomas J. Miller ◽  
Stéphane Cyr ◽  
William C. Leggett

1979 ◽  
Vol 36 (1) ◽  
pp. 37-41 ◽  
Author(s):  
John R. M. Kelso ◽  
John K. Leslie

Larval fish were sampled by net in Lake Huron and the Douglas Point generating station throughout spring, summer, and early fall 1975. Dominance shifted from fourhorn sculpin (Myoxocephalus quadricornis) to rainbow smelt (Osmerus mordax) then to ale-wife (Alosa pseudoharengus) from late April to late September. Entrainment of the major species paralleled dominance and abundance observed in the lake, but yellow perch (Perca flavescens), brook stickleback (Eucalia inconstans), and slimy sculpin (Cottus cognatus) caught in the lake — each ranging from 5 to 25% of the total catch — were not entrained. Conversely, white sucker (Catostomus commersoni) was entrained but not captured in the lake. Size of individuals entrained, upper limit approx. 40 mm, paralleled size of individuals in the lake. Vertical distribution, and thus proximity to the submerged intake, greatly influenced entrainment rate. Key words: larval fish, entrainment, power plant, distribution, abundance.


1993 ◽  
Vol 71 (6) ◽  
pp. 1153-1160 ◽  
Author(s):  
J. K. Leslie ◽  
C. A. Timmins

Thirty-eight taxa of young-of-the-year fishes were collected with a beach seine and plankton nets in Mitchell Bay, a shallow, densely vegetated embayment on Lake St. Clair, from April to October, 1983, 1984, and 1990. The ecosystem of the bay and adjacent land has been altered by agricultural, industrial, and recreational development for more than a century. Although taxa were numerous, most species were rare or uncommon in collections. The assemblage of larval fish consisted primarily of brook silverside (Labidesthes sicculus), pumpkinseed (Lepomis gibbosus), spottail shiner (Notropis hudsonius), emerald shiner (Notropis atherinoides), alewife (Alosa pseudoharengus), and gizzard shad (Dorosoma cepedianum). Many species were distributed in or near submerged macrophytes at the shore. The species most abundant were pumpkinseed, which reached peak density (11 931 young of the year/100 m3) in late June 1990, and brook silverside (1363 young of the year/100 m3) in late June 1984.


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