Prey consumption by the burbot (Lota lota) population in Green Bay, Lake Michigan, based on a bioenergetics model

1995 ◽  
Vol 52 (5) ◽  
pp. 1074-1082 ◽  
Author(s):  
Lars G. Rudstam ◽  
Paul E. Peppard ◽  
Thomas W. Fratt ◽  
Richard E. Bruesewitz ◽  
Daniel W. Coble ◽  
...  

We estimated prey consumption by burbot (Lota lota) based on diet, mortality, growth, maturity, thermal history, population density and a bioenergetics model derived for a similar, cold-water gadoid, the Atlantic cod (Gadus morhua). In Green Bay, Lake Michigan, burbot >400 mm fed primarily on fish; smaller burbot probably fed mostly on invertebrates and sculpins (Cottus sp.). Our calculations indicate that burbot of age ≥1 consumed 16 kg/ha of prey (12.2 kg/ha of fish) in 1988 in the Wisconsin waters of Green Bay including 3.3, 2.1, 1.9, 1.2, and 0.8 kg/ha of rainbow smelt (Osmerus mordax), sculpins, alewife (Alosa pseudoharengus), yellow perch (Perca flavescens), and bloater (Coregnus hoyi), respectively. On an areal basis, piscivory by burbot in Green Bay was higher than the reported lake-wide average for consumption by all salmonids in Lake Michigan. Burbot consumed about 25% of the lake-wide salmonid consumption of alewife per unit area and close to the estimated combined commercial and sport harvest of yellow perch in the Bay the same year (271 vs. 325 tons). Thus, burbot should be included when considering the balance between predatory demand and forage fish production in Green Bay and probably also in other areas of Lake Michigan.

2018 ◽  
Vol 44 (5) ◽  
pp. 851-863 ◽  
Author(s):  
Brice K. Grunert ◽  
Shelby L. Brunner ◽  
Sajad A. Hamidi ◽  
Hector R. Bravo ◽  
J. Val Klump

2019 ◽  
Vol 76 (9) ◽  
pp. 1515-1527 ◽  
Author(s):  
Björn Björnsson

This study supports the hypothesis that well-fed cod (Gadus morhua) seek higher temperatures to increase growth rate, and poorly fed cod select lower temperatures to save metabolic energy. Depth and temperature of free-ranging adult cod (44–79 cm) were studied with data storage tags as part of a ranching project in an Icelandic fjord. Forage fish were regularly provided at four feeding stations where cod formed distinct “herds” (herd cod) that did not mingle much with the rest of the unconditioned cod in the fjord (wild cod). Several parameters (stomach fullness, liver index (fat reserves), condition factor, and growth rate) indicated that food intake was much greater in herd cod than in wild cod. In August, when the thermocline was well established, the herd cod remained in shallow (15–35 m) and warm water (8–10 °C), whereas the wild cod stayed in deep (80–90 m) and cold water (3–4 °C), but occasionally both groups explored depths and temperatures outside their preferred range. After vertical mixing in autumn when thermoregulation was not possible, the depth difference between the two groups decreased significantly.


2008 ◽  
Vol 154 (5) ◽  
pp. 823-832 ◽  
Author(s):  
L. A. Copeman ◽  
C. C. Parrish ◽  
R. S. Gregory ◽  
J. S. Wells

1982 ◽  
Vol 39 (12) ◽  
pp. 1563-1568 ◽  
Author(s):  
John H. Hartig ◽  
David J. Jude ◽  
Marlene S. Evans

Cyclopoid predation on fish larvae, as evidenced by copepods attached to larvae in field collections, was quantitatively investigated during 1975–76 in southeastern Lake Michigan. Although six species of fish larvae were collected, predation occurred primarily (98%) on alewife (Alosa pseudoharengus); 2% of the predators were attached to spottail shiner (Notropis hudsonius) larvae. No cyclopoids were observed on rainbow smelt (Osmerus mordax), yellow perch (Perca flavescens), common carp (Cyprinus carpio), or sculpin (Cottus spp.) larvae. Most alewife larvae attacked were 3–8 mm long; older larvae and larvae of more robust species, such as yellow perch and spottail shiner, are apparently immune to such predation. Most predation (99%) occurred in July when alewife larvae were numerous and cyclopoids abundant. Fish larvae with attached copepods were found only in night collections. Most cyclopoid predators (99%) were adult female Diacyclops thomasi and Acanthocyclops vernalis. Other predaceous species of zooplankton, that occurred in close temporal and spatial proximity to fish larvae, apparently were not predaceous on these organisms.Key words: Alosa pseudoharengus larvae, Notropis hudsonius larvae, Diacyclops thomasi, Acanthocyclops vernalis, cyclopoid predation, Lake Michigan


1981 ◽  
Vol 38 (1) ◽  
pp. 120-125 ◽  
Author(s):  
Ibrahim H. Zeitoun ◽  
John A. Gulvas ◽  
Doyle B. Roarabaugh

Samples of ichthyoplankton entrained through 2.0-mm and 9.5-mm-slot opening cylindrical wedge-wire screens and through an open pipe (control) were collected in June, July, and August 1979, 1067 m off the southeast shore of Lake Michigan at a depth of 10.7 m. Screens were designed for a flow rate of 1.9 m3 min−1 at 15.2 cm s−1 through slot velocity. Ambient composition and density of ichthyoplankton were determined by net tows. Rainbow smelt (Osmerus mordax), alewife (Alosa pseudoharengus), and yellow perch (Perca flavescens) larvae were common in both entrainment and tow collections. Eggs were found almost exclusively in entrainment collections. Ambient larval fish densities were about 11 times greater than those found in entrainment collections. Total entrainments through either screen and the open pipe were not statistically significant. Larval avoidance and, to a lesser extent, screen exclusion were responsible for the low entrainment. We estimated that about 90% of native fish larvae at the site avoided pumping.Key words: Lake Michigan, fish larvae, fish eggs, ichthyoplankton, entrainment, power plants, avoidance


1999 ◽  
Vol 56 (11) ◽  
pp. 2069-2077 ◽  
Author(s):  
B Planque ◽  
T Frédou

Variability in the recruitment of fish has been attributed to either changes in the environment or variations in the size of reproductive stocks. Disentangling the effects of environment and stock has proven to be problematic and has resulted in recurrent controversy between studies supporting either hypothesis. In the present study, we examine the relationship between interannual changes in temperature and variation in recruitment for nine Atlantic cod (Gadus morhua) stocks in the North Atlantic. We show that for individual stocks, the relationship often appears weak and statistically not significant. On the other hand, by combining in a single metaanalysis the results from individual stocks, we demonstrate that recruitment of Atlantic cod is linked to interannual fluctuations in temperature in such a way that for stocks located in warm water the relationship is negative, for stocks located in cold water the relationship is positive, and there is no relationship for stocks located in the middle of the temperature range.


1966 ◽  
Vol 23 (7) ◽  
pp. 1063-1081 ◽  
Author(s):  
W. A. MacCallum ◽  
E. J. Laishley ◽  
W. J. Dyer ◽  
D. R. Idler

Taste panel assessment is reported for Atlantic cod (Gadus morhua) frozen once and twice, and stored at −23 C. The fish were bled, gutted, and iced immediately after capture, and frozen as fillets or dressed fish before, during, and after rigor mortis. Dressed fish were thawed later in recirculated tap water, then processed, refrozen, and stored as fillets. The procedure was conducted three times (June 27, July 19, July 30) during the inshore trap fishery and twice (March and October) during the offshore Grand Bank fishery.For trap-caught landings, the quality of the stored fillets frozen once depended upon the season of catch; for Grand Bank cod, upon the time and place of catching. Trap fish, feeding lightly, caught in cold water in June, were of best quality, grades equalling 70 and over after 20 weeks storage. Those caught on July 30 while feeding heavily in warm water were second; the July 19 fish, obtained under nearly similar conditions, were not significantly poorer than those taken on July 30 and were still acceptable. March landings of Grand Bank fish, once frozen, scored over 70 after 20 weeks storage; October landings only 40 (borderline quality) after 30 weeks. Physiochemical and chemical assessment confirmed the poor quality of the latter.Thawing, refreezing, and storage of June trap fish longer than a few weeks resulted in poor but still acceptable samples. The stored product was soon similar in quality to samples prepared from July landings. In contrast, twice-frozen samples prepared from the March landings from the Grand Bank continued to score high, 70 after 28 weeks storage. Refrozen October samples from the Grand Bank yielded much lower scores, similar to those given the once-frozen samples of the same catch. Thus, in general, an acceptable or better twice-frozen product was obtained by starting with material well handled and quickly chilled, from either the inshore or offshore fishery.


1994 ◽  
Vol 51 (9) ◽  
pp. 1959-1966 ◽  
Author(s):  
Amanda L. Brooker ◽  
Doug Cook ◽  
Paul Bentzen ◽  
Jonathan M. Wright ◽  
Roger W. Doyle

Microsatellites, in particular (dG-dT)n and (dG-dA)n dinucleotide repeats, are abundant and display a high degree of length polymorphism and heterozygosity in eukaryotic genomes. Here, we report the cloning and characterization of 64 microsatellite sequences from Atlantic cod, Gadus morhua. The microsatellites were classified as perfect, imperfect, and compound repeats. The length and integrity of these repeats were compared with microsatellites characterized from two other teleosts, rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar), and from three mammalian genomes, human, porcine, and canine. Differences were found in the proportions of the repeat classes; however, the most significant difference between microsatellites from teleost fishes and mammals was the propensity of the former to be of greater length: some cod and rainbow trout microsatellites were more than twice the size of the longest microsatellite repeats reported for any mammalian genome. Primers for PCR amplification were constructed for seven of the cod microsatellites. Allele frequencies, degree of polymorphism, and heterozygosity were estimated for a sample population. Amplification with these cod primers was also carried out on a number of related gadids. These polymorphic microsatellite loci have enormous potential utility as genetic markers for use in population, breeding, and evolutionary studies.


2000 ◽  
Vol 78 (4) ◽  
pp. 538-555 ◽  
Author(s):  
J P Carney ◽  
T A Dick

Twenty-eight parasite species were recorded from 504 yellow perch (Perca flavescens) collected from Dauphin Lake and Beaufort Lake, Manitoba, and Lake Winnebago, Green Bay, and Lake Michigan, Wisconsin. Four parasite species, Diplostomum spp., Urocleidus adspectus, Proteocephalus pearsei, and Raphidascaris acus, occurred in perch from all localities. Infracommunities and component communities were low in richness. The Dauphin Lake and Beaufort Lake samples had the richest parasite communities, while those in the Green Bay and Lake Michigan samples were the least rich. The effect of host size and age on parasite community structure was equivocal. A positive association between P. pearsei and Bothriocephalus cuspidatus and more multispecies infracommunities than expected provide evidence of nonrandom associations in the Manitoba samples, while the Wisconsin infracommunities were random associations. Significant infracommunity nestedness in all samples indicated nonrandom community organization and structure. Parasite faunas were richer in samples with complex invertebrate communities than in samples with complex fish communities. The trophic status of the aquatic system indirectly affected the parasite communities by limiting the variety of potential intermediate hosts. Predictions regarding relationships between parasite community structure and lake trophic status were not supported. We show that predictable patterns at the fine-scale local level of the parasite infracommunity and component communities of perch are best explained by a rich invertebrate community upon which the host feeds.


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