Summer ichthyoplankton communities of two estuarine systems of Prince Edward Island

1988 ◽  
Vol 66 (3) ◽  
pp. 737-745 ◽  
Author(s):  
C. E. Johnston ◽  
M. Morse
Keyword(s):  
Prince Edward Island ◽  
Gasterosteus Aculeatus ◽  
Larval Fish ◽  
River Estuary ◽  
River System ◽  
Abundant Species ◽  
Average Concentration ◽  
Osmerus Mordax ◽  
Alosa Pseudoharengus ◽  
Atlantic Mackerel

Fish eggs and (or) larvae representing 22 species in 14 families were collected during the summer of 1983 at eight stations in the Hillsborough River estuary – Northumberland Strait area and three stations in the Tracadie Bay – Gulf of St. Lawrence region. Of the 62 287 eggs collected, 83.5% were either yellowtail flounder, Limanda ferruginea, or cunner, Tautogolabrus adspersus, and 5.9% were Atlantic mackerel, Scomber scombrus. The most abundant larvae were alewife, Alosa pseudoharengus, Atlantic mackerel, and cunner accounting for 24.6, 22.4, and 20.6%, respectively, of the total 5077 larvae and juveniles collected. The highest average concentration of eggs and larvae occurred in the coastal area near Tracadie Bay (4265 eggs/100 m3, 350 larvae/100 m3), in the Northumberland Strait region (2682 eggs/100 m3), and at the head of the Hillsborough River system (170 larvae/100 m3). The greatest species diversity occurred near Tracadie Bay (5.0 species of larval fish per tow) and in Tracadie Bay channel (4.0 species of larval fish, 6.0 species of eggs per tow). Summer variations in abundance and distribution were correlated with water temperature and salinity for the more abundant species (alewife, cunner, Atlantic mackerel, Gasterosteus aculeatus, Morone americana, Osmerus mordax, Menidia menidia, Pseudopleuronectes americanus). Species associations and station assemblages were analyzed using the Bray – Curtis dissimilarity measure and a numerical classification system.

scholarly journals Long-term assessment of ichthyoplankton in a large North American river system reveals changes in fish community dynamics

2018 ◽  
Vol 75 (12) ◽  
pp. 2255-2270 ◽  
Author(s):  
Taaja R. Tucker ◽  
Edward F. Roseman ◽  
Robin L. DeBruyne ◽  
Jeremy J. Pritt ◽  
David H. Bennion ◽  
...  
Keyword(s):  
Community Dynamics ◽  
Larval Fish ◽  
River System ◽  
Early Spring ◽  
Spatial And Temporal Variability ◽  
Osmerus Mordax ◽  
Alosa Pseudoharengus ◽  
Rainbow Smelt ◽  
Detroit River ◽  
Larval Fishes

Larval fishes are sensitive to abiotic conditions and provide a direct measure of spawning success. The St. Clair – Detroit River System, a Laurentian Great Lakes connecting channel with a history of environmental degradation, has undergone improvements in habitat and water quality since the 1970s. We compared 2006–2015 ichthyoplankton community data with those collected prior to remediation efforts (1977–1978) to identify patterns in spatial and temporal variability. Both assemblages exhibited a predictable phenology, with taxa from the subfamily Coregoninae dominant in early spring followed by families Osmeridae, Percidae, and Moronidae (May–June) and Cyprinidae and Clupeidae (June–August). While higher densities of larval fish were found in the Detroit River, greater taxa richness and Shannon diversity were observed in the St. Clair River. System wide, 14 new taxa were observed in the 2000s study period. In addition, relative densities of two nonnative species, alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax), declined since the 1970s. Increased larval fish richness and decreased densities of nonnative taxa in the 2000s are consistent with improvements to environmental conditions.

Parasites of Freshwater and Anadromous Fishes from Matamek River System, Quebec

1974 ◽  
Vol 31 (6) ◽  
pp. 1135-1139 ◽  
Author(s):  
George Hanek ◽  
Kalman Molnar
Keyword(s):  
Salmo Salar ◽  
Gasterosteus Aculeatus ◽  
Salvelinus Fontinalis ◽  
River System ◽  
Anguilla Rostrata ◽  
Osmerus Mordax ◽  
Pungitius Pungitius ◽  
Apeltes Quadracus ◽  
Catostomus Catostomus

In 224 fish of nine species from Matamek River system 38 genera of parasites were recovered (12 Protozoa, 3 Monogenea, 6 Digenea, 6 Cestoda, 6 Nematoda, 2 Acanthocephala, 3 Copepoda). Six genera of parasites were noted in Salmo salar, Salvelinus fontinalis harbored 17 genera, S. alpinus 5 genera, Osmerus mordax 4 genera, Anguilla rostrata 9 genera, Catostomus catostomus 8 genera, Apeltes quadracus 1 genus, Gasterosteus aculeatus 12 genera, and Pungitius pungitius 9 genera.

Entrainment of Larval Fish by the Douglas Point Generating Station, Lake Huron, in Relation to Seasonal Succession and Distribution

1979 ◽  
Vol 36 (1) ◽  
pp. 37-41 ◽  
Author(s):  
John R. M. Kelso ◽  
John K. Leslie
Keyword(s):  
Yellow Perch ◽  
Larval Fish ◽  
Seasonal Succession ◽  
Lake Huron ◽  
Plant Distribution ◽  
Entrainment Rate ◽  
Osmerus Mordax ◽  
Alosa Pseudoharengus ◽  
Rainbow Smelt ◽  
Early Fall

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.

Climate-associated trends and variability in ichthyoplankton phenology from the longest continuous larval fish time series on the east coast of the United States

2020 ◽  
Vol 650 ◽  
pp. 269-287
Author(s):  
WC Thaxton ◽  
JC Taylor ◽  
RG Asch
Keyword(s):  
United States ◽  
Environmental Variability ◽  
Larval Fish ◽  
Interspecific Interactions ◽  
River Estuary ◽  
Atlantic Multidecadal Oscillation ◽  
The United States ◽  
Larval Survival ◽  
Ecological Communities ◽  
Northerly Wind

As the effects of climate change become more pronounced, variation in the direction and magnitude of shifts in species occurrence in space and time may disrupt interspecific interactions in ecological communities. In this study, we examined how the fall and winter ichthyoplankton community in the Newport River Estuary located inshore of Pamlico Sound in the southeastern United States has responded to environmental variability over the last 27 yr. We relate the timing of estuarine ingress of 10 larval fish species to changes in sea surface temperature (SST), the Atlantic Multidecadal Oscillation, the North Atlantic Oscillation, wind strength and phenology, and tidal height. We also examined whether any species exhibited trends in ingress phenology over the last 3 decades. Species varied in the magnitude of their responses to all of the environmental variables studied, but most shared a common direction of change. SST and northerly wind strength had the largest impact on estuarine ingress phenology, with most species ingressing earlier during warm years and delaying ingress during years with strong northerly winds. As SST warms in the coming decades, the average date of ingress of some species (Atlantic croaker Micropogonias undulatus, summer flounder Paralichthys dentatus, pinfish Lagodon rhomboides) is projected to advance on the order of weeks to months, assuming temperatures do not exceed a threshold at which species can no longer respond through changes in phenology. These shifts in ingress could affect larval survival and growth since environmental conditions in the estuarine and pelagic nursery habitats of fishes also vary seasonally.

Temporal variation of larval fish assemblages of the Murray Mouth in prolonged drought conditions

2013 ◽  
Vol 64 (10) ◽  
pp. 932 ◽  
Author(s):  
L. B. Bucater ◽  
J. P. Livore ◽  
C. J. Noell ◽  
Q. Ye
Keyword(s):  
Fish Assemblages ◽  
Larval Fish ◽  
River System ◽  
Sampling Period ◽  
Marine Species ◽  
Flow Regulation ◽  
Nursery Areas ◽  
Transition Zones ◽  
Murray Darling Basin ◽  
Drought Conditions

Estuaries are transition zones that link freshwater and marine ecosystems and are often used as nursery areas by fish. The Murray–Darling Basin, which is heavily affected by flow regulation and water extraction, is the largest river system in Australia and terminates at the Murray Mouth estuary. Protracted drought conditions resulted in extremely low flows to the Murray Mouth that affected water condition, fish abundance, community structure and fish use of the estuary (e.g. nursery areas). The aims of the present study were to examine temporal changes in larval fish assemblages in this estuary. The assemblages were dominated by two gobiid species, Arenigobius bifrenatus and Tasmanogobius lasti. There was a noticeable absence or low abundance of freshwater, diadramous and large-bodied marine species that use this estuary for reproductive functions. Monthly differences in larval fish assemblages, between August–September and October–November, were attributed to increases in the abundances of A. bifrenatus in October and November and oscillation in T. lasti during the entire sampling period. The outcomes of the present study suggested that larval fish assemblages in drought conditions are limited to small-bodied species tolerant of high salinities and that freshwater flows are needed for the estuary to function as a nursery for other species.

A Study of Campylobacter in Sewage, Sewage Sludge and in River Water

1991 ◽  
Vol 24 (2) ◽  
pp. 117-120 ◽  
Author(s):  
W. Stelzer ◽  
J. Jacob
Keyword(s):  
Sewage Sludge ◽  
Treatment Plant ◽  
Electrophoretic Pattern ◽  
River System ◽  
Average Concentration ◽  
Selective Medium ◽  
Cell Protein ◽  
Oxidation Pond ◽  
River Waters ◽  
Whole Cell Protein

This study is aimed at determining the occurrence of campylobacters in waste water, sewage sludge and in a river system. The selective medium for the isolation of campylobacter consists of blood agar supplemented with the antibiotics vancomycin (10 µg/ml), cephalexin (15 µg/ml), trimethoprim (5 µg/ml), polymycin B (2.5 µg/ml) and rifampicin (5 µg/ml). Raw sewage samples contained about 103 Campylobacter/100 ml while the effluent showed an average concentration of 1.3 × 102/100 ml. Raw sewage from an oxidation pond treatment plant contained an average of 51 Campylobacter/100 ml while none were found in the effluent. No Campylobacter could be found in digested, conditioned sludge. The organism could be detected in 82.1% of river waters examined with the majority showing <10/100 ml. The presence of waterfowl and the faecal contamination from a poultry farm resulted in higher Campylobacter levels. About 50 % of the isolates typed as C. coli were really confirmed as C. jejuni by electrophoretic pattern (whole cell protein profiles).

Planktivory by alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) on microcrustacean zooplankton and dreissenid (Bivalvia: Dreissenidae) veligers in southern Lake Ontario

1995 ◽  
Vol 52 (5) ◽  
pp. 925-935 ◽  
Author(s):  
Edward L. Mills ◽  
Connie Adams ◽  
Robert O'Gorman ◽  
Randall W. Owens ◽  
Edward F. Roseman
Keyword(s):  
Laboratory Experiments ◽  
Lake Ontario ◽  
Osmerus Mordax ◽  
Field Observations ◽  
Alosa Pseudoharengus ◽  
Rainbow Smelt ◽  
Consumption Rates ◽  
South Shore ◽  
Young Of The Year ◽  
Veliger Larvae

The objective of this study was to describe the diet of young-of-the-year and adult alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) in nearshore waters coincident with the colonization of Lake Ontario by Dreissena. Laboratory experiments and field observations indicated that alewife and rainbow smelt consumed dreissenid veligers and that the veligers remained intact and identifiable in the digestive tract for several hours. Dreissenid larvae were found in field-caught alewife and rainbow smelt in August 1992, even though veliger densities were low (<0.1/L). Zooplankton dominated the diet of all fish and veliger larvae were <0.1% of the biomass of prey eaten by these fish. Density of veligers and the distribution of settled dreissenids declined from west to east along the south shore of Lake Ontario. Based on veliger consumption rates we measured and the abundance of veligers and planktivores, we conclude that planktivory by alewife and smelt in the nearshore waters of Lake Ontario did not substantially reduce the number of veligers during 1991–1993. However, our results indicate that if the density of veligers in Lake Ontario decreases, and if planktivores remain abundant, planktivory on veliger populations could be significant.

Early Life Stage Mortality Syndrome in Fishes of the Great Lakes and Baltic Sea

1998 ◽  
Keyword(s):  
Great Lakes ◽  
Prey Species ◽  
Lake Trout ◽  
Life Stage ◽  
Species Variation ◽  
Osmerus Mordax ◽  
Alosa Pseudoharengus ◽  
Rainbow Smelt ◽  
Thiamine Content ◽  
Lake Variation

<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.

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