Alewife (Alosa pseudoharengus) Survival During the First Growth Season in Southeastern Lake Michigan

1986 ◽  
Vol 43 (7) ◽  
pp. 1318-1326 ◽  
Author(s):  
Pamela J. Mansfield ◽  
David J. Jude

Alewife (Alosa pseudoharengus) survival from newly hatched larvae to fall young-of-the-year (YOY) was calculated using data collected in southeastern Lake Michigan, June–November 1974–82. Alewife YOY density (number per 1000 m3) was estimated from trawl catches. Larval alewife densities, derived from plankton net samples at trawling stations and from power plant entrainment samples, were averaged each year for length intervals which represented yolk-sac and post-yolk-sac larvae. Survival (ratios of YOY to larval alewife densities) varied considerably among years, but mean survival over all years from yolk-sac larvae to YOY was 1% calculated from either field-larvae or entrained-larvae data. Mean survival from post-yolk-sac larvae to YOY was higher, 2.2–4.6%. Daily mortality rates were 12–27% for larvae through yolk absorption, decreasing to 2–5% for juveniles. Differences in survival among years may be due to timing of sampling, distribution of larvae and YOY, or actual survival differences, perhaps related to predator abundance.

2015 ◽  
Vol 41 (2) ◽  
pp. 436-447 ◽  
Author(s):  
Michael J. Weber ◽  
Blake C. Ruebush ◽  
Sara M. Creque ◽  
Rebecca A. Redman ◽  
Sergiusz J. Czesny ◽  
...  

2012 ◽  
Vol 4 (2) ◽  
Author(s):  
Wawan Andriyanto ◽  
Muhammad Marzuqi

The experiment was carried out to determine the exposure time of the first mouth opening on humpback grouper larval from F2 broodstock on hatchery until 10 DAH (days after hatching) because this phase is a critical phase of larval adaptation from food endogenous (from yolk sac) to the ability of absorbing nutrients from external (exogenous). The eggs used were collected from natural spawning of second generation of humpback grouper reared in the tank size of 150 litre. The mouth opening was observed at 90 and 45 degrees under computerize integrated microscope and processed by a specific software. The rate of yolk absorption was observed in larvae from the beginning to the end of breeding, while the activities of digestive enzymes (trypsin and chymotripsin) were analyzed by enzyme assay techniques. The results showed that the period of mouth opening of larvae of humpback grouper occurred at 3 DAH with mouth openings of 45° as large as 0.103 mm and of 90° as large as 0.156 mm. In the early stadia, the diameter of yolk was 0.1875 mm, while the oil globule was 0.0537 mm. At 4 days after hatching, the yolk and oil globule had been absorbed, while the enzymes trypsin and chymotripsin were detected in the early stadia. The results also showed that the larvae was started to use foods from outside after the age of 4 DAH. Up to the age of 10 days, the mouth opening increased and the activity of trypsin and chymotripsin were still detected.Keywords: progeny larvae of humpback grouper F2, mouth opening, yolk sac, enzyme


1983 ◽  
Vol 40 (6) ◽  
pp. 681-698 ◽  
Author(s):  
Donald J. Stewart ◽  
David Weininger ◽  
Donald V. Rottiers ◽  
Thomas A. Edsall

An energetics model is implemented for lake trout, Salvelinus namaycush, and applied to the Lake Michigan population. It includes an egestion function allowing any proportional mix of fish and invertebrates in the diet, a growth model accounting for both ontogenetic and seasonal changes in energy-density of predator and prey, a model for typical in situ swimming speed, and reproductive energy losses due to gametes shed. Gross conversion efficiency of energy by lake trout over their life (21.8%) is about twice the efficiency of converting biomass to growth because they store large amounts of high-energy fats. Highest conversion efficiencies are obtained by relatively fast-growing individuals, and over half the annual energy assimilated by older age-classes may be shed as gametes. Sensitivity analysis indicates a general robustness of the model, especially for estimating consumption by fitting a known growth curve. Largest sensitivities were for the intercept and weight dependence coefficients of metabolism. Population biomass and associated predatory impact of a given cohort increase steadily for about 3.5 yr then decline steadily after fishing mortality becomes important in the fourth year in the lake. This slow response time precludes manipulation of lake trout stocking densities as a means to control short-term prey fluctuations. Predation by lake trout on alewife, Alosa pseudoharengus, has been increasing steadily since 1965 to about 8 400 t∙yr−1, and is projected to rise to almost 12 000 t∙yr−1 by 1990.


Zygote ◽  
2017 ◽  
Vol 25 (2) ◽  
pp. 149-159 ◽  
Author(s):  
Camila Marques ◽  
Francine Faustino ◽  
Bruno Bertolucci ◽  
Maria do Carmo Faria Paes ◽  
Fernanda Nogueira Valentin ◽  
...  

SummaryThe Zungaro jahu is an important large catfish of the order Siluriformes that is in danger of extinction due to habitat destruction. Studies on its biology are scarce and the majority relates only to nutrition or parasitology. In order to provide greater information on its morphology and aid husbandry and larviculture studies, the aim of this study was to characterize larval development in Z. jahu from hatching to total yolk absorption. Samples were collected at pre-established times, processed, stained, and analyzed under stereomicroscopy, light microscopy, and scanning electron microscopy. Total yolk absorption was observed by 60 hours post-hatching (hph) at 28.75 ± 0.59°C. The newly hatched larvae showed slightly pigmented body, the outline of the digestive tract, evident eyes, and the first swimming movements. Mouth opening took place at 12 hph and the connection between the oral cavity and the rudimentary intestine was observed at 24 hph. Were analyzed the main larval organs and systems: digestive organs, heart, gill arches, sensory system, thyroid, kidney, and swim bladder. As the larvae grew, these organs became more mature and functional. The development of the sensory and feeding structures was observed at the start of larval development, and thus before depletion of endogenous energy reserves, the strategy for this species is to increase its chances of survival in the environment.


Copeia ◽  
1970 ◽  
Vol 1970 (4) ◽  
pp. 766 ◽  
Author(s):  
Edward H. Brown ◽  
Carroll R. Norden

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


2002 ◽  
Vol 59 (4) ◽  
pp. 736-753 ◽  
Author(s):  
Charles P Madenjian ◽  
Gary L Fahnenstiel ◽  
Thomas H Johengen ◽  
Thomas F Nalepa ◽  
Henry A Vanderploeg ◽  
...  

Herein, we document changes in the Lake Michigan food web between 1970 and 2000 and identify the factors responsible for these changes. Control of sea lamprey (Petromyzon marinus) and alewife (Alosa pseudoharengus) populations in Lake Michigan, beginning in the 1950s and 1960s, had profound effects on the food web. Recoveries of lake whitefish (Coregonus clupeaformis) and burbot (Lota lota) populations, as well as the buildup of salmonine populations, were attributable, at least in part, to sea lamprey control. Based on our analyses, predation by salmonines was primarily responsible for the reduction in alewife abundance during the 1970s and early 1980s. In turn, the decrease in alewife abundance likely contributed to recoveries of deepwater sculpin (Myoxocephalus thompsoni), yellow perch (Perca flavescens), and burbot populations during the 1970s and 1980s. Decrease in the abundance of all three dominant benthic macroinvertebrate groups, including Diporeia, oligochaetes, and sphaeriids, during the 1980s in nearshore waters ([Formula: see text]50 m deep) of Lake Michigan, was attributable to a decrease in primary production linked to a decline in phosphorus loadings. Continued decrease in Diporeia abundance during the 1990s was associated with the zebra mussel (Dreissena polymorpha) invasion, but specific mechanisms for zebra mussels affecting Diporeia abundance remain unidentified.


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