Long-term development of fish populations in the Římov Reservoir

2009 ◽  
Vol 16 (2) ◽  
pp. 121-129 ◽  
Author(s):  
M. ŘÍHA ◽  
J. KUBEČKA ◽  
M. VAŠEK ◽  
J. SEĎA ◽  
T. MRKVIČKA ◽  
...  
Keyword(s):  
Fish Populations ◽  
Římov Reservoir

scholarly journals Indicators of AEI Applied to the Delaware Estuary

2002 ◽  
Vol 2 ◽  
pp. 169-189 ◽  
Author(s):  
Lawrence W. Barnthouse ◽  
Douglas G. Heimbuch ◽  
Vaughn C. Anthony ◽  
Ray W. Hilborn ◽  
Ransom A. Myers
Keyword(s):  
Meta Analysis ◽  
Juvenile Fish ◽  
Fish Populations ◽  
Weight Of Evidence ◽  
Data Sets ◽  
Delaware Estuary ◽  
Fish Stocks ◽  
Trends Analysis ◽  
Definition Of

We evaluated the impacts of entrainment and impingement at the Salem Generating Station on fish populations and communities in the Delaware Estuary. In the absence of an agreed-upon regulatory definition of “adverse environmental impact” (AEI), we developed three independent benchmarks of AEI based on observed or predicted changes that could threaten the sustainability of a population or the integrity of a community.Our benchmarks of AEI included: (1) disruption of the balanced indigenous community of fish in the vicinity of Salem (the “BIC” analysis); (2) a continued downward trend in the abundance of one or more susceptible fish species (the “Trends” analysis); and (3) occurrence of entrainment/impingement mortality sufficient, in combination with fishing mortality, to jeopardize the future sustainability of one or more populations (the “Stock Jeopardy” analysis).The BIC analysis utilized nearly 30 years of species presence/absence data collected in the immediate vicinity of Salem. The Trends analysis examined three independent data sets that document trends in the abundance of juvenile fish throughout the estuary over the past 20 years. The Stock Jeopardy analysis used two different assessment models to quantify potential long-term impacts of entrainment and impingement on susceptible fish populations. For one of these models, the compensatory capacities of the modeled species were quantified through meta-analysis of spawner-recruit data available for several hundred fish stocks.All three analyses indicated that the fish populations and communities of the Delaware Estuary are healthy and show no evidence of an adverse impact due to Salem. Although the specific models and analyses used at Salem are not applicable to every facility, we believe that a weight of evidence approach that evaluates multiple benchmarks of AEI using both retrospective and predictive methods is the best approach for assessing entrainment and impingement impacts at existing facilities.

An Evaluation of RNA–DNA Ratio as a Measure of Long-Term Growth in Fish Populations

1973 ◽  
Vol 30 (2) ◽  
pp. 195-199 ◽  
Author(s):  
Terry A. Haines
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Growth Rates ◽  
Population Growth Rate ◽  
Environmental Changes ◽  
Age Distribution ◽  
Smallmouth Bass ◽  
Fish Populations ◽  
Population Growth Rates

The value of RNA–DNA ratio as a measure of long-term growth of fish populations under semi-natural conditions and when subjected to environmental manipulations was determined. Populations of carp and smallmouth bass of known age distribution were established in artificial ponds maintained at two fertility levels. After 15 months, population growth rates (as percent increase in weight) and RNA–DNA ratios of muscle tissue from selected fish were measured. Each species exhibited a range of population growth rates. The relation between population growth rate and individual fish RNA–DNA ratio for each species was significant. When reproduction occurred, the relation was not significant unless young-of-the-year fish were excluded from population growth rate calculations. Age of fish was also found to have an important effect on RNA–DNA ratio, with the ratio being higher in younger fish.RNA–DNA ratio can be a reliable indicator of long-term population growth in fish when population age structure is known and recruitment is controlled. The method has potential for use in detecting response to environmental changes before growth rate changes become severe.

Freshwater, Fish and the Future: Proceedings of the Global Cross-Sectoral Conference

2016 ◽  
Keyword(s):  
Fish Populations ◽  
Native Fish ◽  
Partnership Model ◽  
European Settlement ◽  
Southeastern Australia ◽  
Murray Darling Basin ◽  
Wide Range ◽  
Funding Opportunities ◽  
Funding Cuts

<em>Abstract</em> .—The Murray–Darling basin (MDB) in southeastern Australia, covers 1.1 million km<sup>2</sup>, involves six partner jurisdictions with a myriad of different government agencies, and, hence, provides an excellent example of the complexities of multijurisdictional management across a range of social and political tiers. In the MDB, fish and fisheries compete for water with agriculture, which is the traditional water user and is driven by national economics. Murray–Darling basin rivers are now highly regulated and generally in poor health, with native fish populations estimated to be at only about 10% of their pre-European settlement abundances. All native commercial fisheries are now closed, and the only harvest is by a recreational fishery. The six partner jurisdictions developed a Native Fish Strategy (NFS) to rehabilitate native fish populations to 60% of pre-European settlement levels after 50 years of implementation by addressing priority threats through a coordinated, long-term, whole-of-fish-community (all native fishes) approach. As there are a wide range of stakeholders, broad engagement was needed at a broad range of government and community levels. The NFS funding was discontinued after 10 years, not because of its lack of successes or project governance, but due to jurisdictional political changes and funding cuts that resulted in a failure of the collaborative funding structure. The withdrawal of considerable funding by one jurisdiction led to collective decline in monetary contributions and posed a threat to the multijurisdictional structures for both water and natural resource management (NRM) within the MDB. As a consequence, there was a review and reduction in NRM programs and a subsequent reduction in focus to the core business of water delivery. Reflection on the NFS, however, provides some useful insights as to the successes (many) and failures (funding) of this partnership model. Overall, the strategy and its structure was effective, as exhibited by an audit of outputs, outcomes, and networks; by the evident ongoing advocacy by NRM practitioners and the community; and by the continuation of ideas under other funding opportunities. This has provided a powerful legacy for future management of fishes in the MDB.

Paleoecological studies on variability in marine fish populations: A long-term perspective on the impacts of climatic change on marine ecosystems

2010 ◽  
Vol 79 (3-4) ◽  
pp. 316-326 ◽  
Author(s):  
Bruce P. Finney ◽  
Jürgen Alheit ◽  
Kay-Christian Emeis ◽  
David B. Field ◽  
Dimitri Gutiérrez ◽  
...  
Keyword(s):  
Climatic Change ◽  
Marine Fish ◽  
Marine Ecosystems ◽  
Fish Populations

Effects of Control of the Sea Lamprey (Petromyzon marinus) on Migratory and Resident Fish Populations

1980 ◽  
Vol 37 (11) ◽  
pp. 1886-1894 ◽  
Author(s):  
F. H. Dahl ◽  
R. B. McDonald
Keyword(s):  
Large Scale ◽  
Petromyzon Marinus ◽  
Sea Lamprey ◽  
Fish Populations ◽  
Long Term Effects ◽  
Migratory Species ◽  
Chemical Treatments ◽  
Catostomus Catostomus ◽  
Noturus Flavus

Information from the records of the various agencies on control of the sea lamprey (Petromyzon marinus) was summarized from the early approach to control by mechanical or electrical barriers and chemical toxicants. While fish kill has been an inescapable consequence of the program, information available for migratory species has shown no large-scale detrimental effects. The only reportable instance of damage to a resident stream species has been the near loss of the stonecat (Noturus flavus) from tributaries to the southwest corner of Lake Superior, resulting from chemical treatments. Although no similar occurrences were recognized, available documentation proved inadequate to record long-term effects on these vulnerable species. As long as existing control methods continue, no matter the precautions taken, fish populations will be affected. Whether or not this remains a tenable situation is a question for this symposium and the future.Key words: weirs, chemicals, fish kills, sea lamprey, Petromyzon marinus; Catostomus catostomus, Catostomus commersoni, Noturus flavus, Salvelinus fontinalis

Long-Term Changes in the Macrobenthos of Southern Lake Michigan

1987 ◽  
Vol 44 (3) ◽  
pp. 515-524 ◽  
Author(s):  
Thomas F. Nalepa
Keyword(s):  
Lake Michigan ◽  
Fish Populations ◽  
Forage Fish ◽  
Future Trends ◽  
Sampling Depth ◽  
Benthic Survey ◽  
Comprehensive Survey ◽  
Long Term Trends

A benthic survey of 40 stations in southern Lake Michigan in 1980–81 was compared with results of studies conducted in the mid-1960's to evaluate long-term trends in populations. The three major benthic groups, Pontoporeia, oligochaetes, and sphaeriids, were significantly more abundant in 1980–81. Compared with the most comprehensive survey (conducted in 1964–67), Pontoporeia increased two- to fivefold at depths less than 50 m, but did not increase at depths greater than 50 m. Oligochaetes increased two- to threefold regardless of sampling depth, while sphaeriids increased twofold at depths less than 50 m but decreased somewhat at depths greater than 50 m. Although oligochaete abundances increased, overall shifts in species composition were not apparent. Changes in abundances of Pontoporeia may have been related to shifts in predation pressure from forage fish populations, but increased oligochaete abundances can likely be related to increased enrichment between the two sampling periods. Although apparent improvements in the water quality of Lake Michigan since the mid-1970's were not yet reflected by benthic populations in 1980–81, continued monitoring of the benthos should provide a useful indicator of future trends.

Impact of shark-feeding tourism on surrounding fish populations off Moorea Island (French Polynesia)

2010 ◽  
Vol 61 (2) ◽  
pp. 163 ◽  
Author(s):  
Matthias Vignon ◽  
Pierre Sasal ◽  
Ryan L. Johnson ◽  
René Galzin
Keyword(s):  
Spatial Patterns ◽  
Host Species ◽  
French Polynesia ◽  
Fish Populations ◽  
North Coast ◽  
Target Fish ◽  
Parasitological Survey ◽  
Moorea Island ◽  
First Time

Shark feeding is widespread throughout tropical, subtropical and temperate marine ecosystems and gives rise to controversy because there is little consensus regarding its management. There are few comprehensive reports that consider how shark feeding with bait might impact local fishes, despite the development of this practice during the last few decades. Although shark feeding might theoretically have parasitological effects on local non-target fish species in the vicinity of feeding areas, this aspect has never been investigated. During an extensive parasitological survey conducted between 2005 and 2007, a total of 1117 fish belonging to six common grouper and snapper species were sampled throughout the entire north coast of Moorea Island (French Polynesia), encompassing three localities where feeding has occurred frequently since the 1990s. Parasites exhibited no spatial patterns except for the infections on the blacktip grouper (Epinephelus fasciatus). On this species, the prevalence of larval cestodes that parasitise sharks as adults and the intensity of their infestation were significantly higher around shark-feeding localities compared with non-shark-feeding localities. Our results suggest for the first time that although long-term shark feeding has parasitological implications, the impacts appear limited, only involve cestode larvae from one host species and do not seem to affect the health of the fish we studied.

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