scholarly journals Contrasting trends between species and catchments in diadromous fish counts over the last 30 years in France

2020 ◽  
pp. 7
Author(s):  
Marion Legrand ◽  
Cédric Briand ◽  
Laëtitia Buisson ◽  
Gwenaël Artur ◽  
Didier Azam ◽  
...  
Keyword(s):  
Salmo Trutta ◽  
Large Range ◽  
Petromyzon Marinus ◽  
Anguilla Anguilla ◽  
Complex Life Cycle ◽  
National Scale ◽  
Anthropogenic Pressures ◽  
Diadromous Fish ◽  
The World ◽  
Ecological Continuity

The decline and collapse of populations have been reported for a large range of taxa. Diadromous fishes migrate between fresh water and the sea and encounter many anthropogenic pressures during their complex life cycle. In spite of being of ecological, cultural and economic interest, diadromous fishes have been in decline for decades in many parts across the world. In this study, we investigated the change in five diadromous fish counts in France over a 30-year period using 43 monitoring stations located in 29 rivers across 18 catchments. Our hypothesis was that the counts of these species evolved in a contrasting way between catchments. We also tested the effect of five drivers potentially contributing to the observed trends: catchment, latitude, presence of commercial fisheries, improvement of ecological continuity and salmon stocking. We found contrasting trends in fish counts between species at the national scale, with some taxa increasing (Anguilla anguilla and Salmo trutta), some showing a slight increase (Salmo salar) and some decreasing (Alosa spp. and Petromyzon marinus). For each taxon, except Anguilla anguilla, we highlighted a significant catchment effect indicating contrasting trends between catchments and stations. However, we found no significant effect of catchment characteristics for any of the studied taxa.

Trends in phytoplankton communities within large marine ecosystems diverge from the global ocean

2021 ◽  
pp. 1-12
Author(s):  
Kevin D. Friedland ◽  
John R. Moisan ◽  
Aurore A. Maureaud ◽  
Damian C. Brady ◽  
Andrew J. Davies ◽  
...  
Keyword(s):  
Chlorophyll Concentration ◽  
World Ocean ◽  
Marine Ecosystems ◽  
Fishing Effort ◽  
Global Ocean ◽  
Human Populations ◽  
Anthropogenic Pressures ◽  
Large Marine Ecosystems ◽  
Phytoplankton Communities ◽  
The World

Large marine ecosystems (LMEs) are highly productive regions of the world ocean under anthropogenic pressures; we analyzed trends in sea surface temperature (SST), cloud fraction (CF), and chlorophyll concentration (CHL) over the period 1998–2019. Trends in these parameters within LMEs diverged from the world ocean. SST and CF inside LMEs increased at greater rates inside LMEs, whereas CHL decreased at a greater rates. CHL declined in 86% of all LMEs and of those trends, 70% were statistically significant. Complementary analyses suggest phytoplankton functional types within LMEs have also diverged from those characteristic of the world ocean, most notably, the contribution of diatoms and dinoflagellates, which have declined within LMEs. LMEs appear to be warming rapidly and receiving less solar radiation than the world ocean, which may be contributing to changes at the base of the food chain. Despite increased fishing effort, fishery yields in LMEs have not increased, pointing to limitations related to productivity. These changes raise concerns over the stability of these ecosystems and their continued ability to support services to human populations.

scholarly journals Documentation of multiple species of marine fish trapped in Atlantic salmon sea-cages in Norway

2018 ◽  
Vol 31 ◽  
pp. 31
Author(s):  
Per Gunnar Fjelldal ◽  
Monica F. Solberg ◽  
Kevin A. Glover ◽  
Ole Folkedal ◽  
Jonatan Nilsson ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Trutta ◽  
Gadus Morhua ◽  
Mesh Size ◽  
Anguilla Anguilla ◽  
Wild Fish ◽  
Melanogrammus Aeglefinus ◽  
European Eel ◽  
Farmed Salmon ◽  
Sea Trout

The production of salmonids in sea-cages has been developed for monoculture of the target species. However, we show here for the first time, that wild fish may enter sea-cages used for farming of Atlantic salmon (Salmo salar L.) in Norway, out-grow the mesh size, and thereafter become permanently trapped. Within seven different sea-cages located in western Norway, eight different species of wild fish were identified; European eel (Anguilla anguilla), sea trout (Salmo trutta L.), cod (Gadus morhua), haddock (Melanogrammus aeglefinus), saithe (Pollachius virens), pollack (Pollachius pollachius), hake (Merluccius merluccius) and whiting (Merlangius merlangus). In the two most extreme cases, a 5 × 5 × 7 m cage with 311 farmed salmon (903 g) also contained 542 whiting (79 g), 77 haddock (43 g), and 5 cod (26 g), and a 12 × 12 × 15 m cage with 1695 farmed salmon (559 g) also contained 1196 haddock (35 g), 1115 whiting (31 g), 46 cod (23 g), 23 saithe (48 g), 15 pollock (22 g), 5 sea trout (54 g), and 2 hake (29 g). The present study thus demonstrates that aquaculture cages designed for monoculture may attract and effectively ‘trap’ wild fish. We did not investigate the frequency of this occurrence, and the ecological significance of these observations remains unclear. However, with the ever-increasing number of sea-cages used for global aquaculture, this is clearly a topic for further research.

scholarly journals Performance Method for Innovative Activity on the Achieved Level of the Country‘s Socioeconomic Development

2020 ◽  
Vol 9 (3) ◽  
pp. 3678-3686
Keyword(s):  
Socioeconomic Development ◽  
Objective Assessment ◽  
Point Of View ◽  
Innovation Activity ◽  
National Scale ◽  
Innovation Development ◽  
Environment Analysis ◽  
The World ◽  
Data Environment ◽  
World Ranking

The purpose of this study is to make an attempt to assess the innovation activity on the achieved result , expressed in indicators that determine the socioeconomic level of country development, as it is the purpose of innovation In the applied method of calculating the evaluation of the effectiveness of innovation (Data environment Analysis) these indicators were the results, while the indicators of innovation were considered as a "resource". Rental indicators, Gini index and others , reflecting (directly or indirectly) the result of innovations was also taken into account. The results showed values that were less inconsistent with the estimates for other related indexes and indicators , while the evaluation with existing methods gave more inaccurate results. This suggests that the proposed method gives a more objective assessment of the innovation level in the country and more accurately determines the country 's place in the world ranking. The main source of the world economy development today is the innovation, an integrated assessment of which on a national scale can itself act as an indicator of the level of economic and — in a broader sense — the socio-economic level of the country development . From this point of view, an objective assessment of the innovation development level, as well as the development and proposal of methods for its evaluation are still relevant. Up-to-date assessment methods mainly assess the potential of countries to develop innovations, while their achieved level should be assessed, since, with significant differences in the development of countries , these potential opportunities can be realized to varying degrees.

Education and national scale: The world of small states

Prospects ◽  
1988 ◽  
Vol 18 (3) ◽  
pp. 302-314 ◽  
Author(s):  
Colin Brock
Keyword(s):  
Small States ◽  
National Scale ◽  
The World

Ramularia leaf spot in barley

2021 ◽  
pp. 681-706
Author(s):  
Neil Havis ◽  
Keyword(s):  
Life Cycle ◽  
Leaf Spot ◽  
Fungicide Resistance ◽  
Complex Life Cycle ◽  
Rate Of Development ◽  
Major Disease ◽  
Ramularia Leaf Spot ◽  
The World ◽  
Causal Pathogen ◽  
And Control

Ramularia leaf spot is an emerging pathogen across barley growing regions of the world. It's rise from minor to major disease has been rapid over the last twenty years. The causal pathogen, Ramularia collo-cygni is poorly understood but it has been shown to have a complex life cycle and the ability to exist on many hosts in an endophytic state. The rate of development of fungicide resistance in the fungus is also extremely fast and many of the major single site fungicides are no longer effective in many countries. With multisite fungicides having their approval or reconsidered and no consistent varietal resistance available, control of the disease is increasing challenging. This chapter reviews the latest research into Ramularia biology and control and highlights the areas where recent advances have been made.

scholarly journals Utilization of brown troutSalmo truttabyAcanthocephalus clavulain an Irish lake: is this evidence of a host shift?

2004 ◽  
Vol 78 (3) ◽  
pp. 201-206 ◽  
Author(s):  
C.J. Byrne ◽  
C.V. Holland ◽  
E. Walsh ◽  
C. Mulligan ◽  
C.R. Kennedy ◽  
...  
Keyword(s):  
Population Biology ◽  
Salmo Trutta ◽  
Anguilla Anguilla ◽  
Host Shift ◽  
Reproductive Maturity ◽  
Large Numbers ◽  
Host Diet ◽  
Potential Competitor ◽  
The Mean ◽  
Accidental Host

AbstractThe population biology of the fish acanthocephalanAcanthocephalus clavulawas described from 161 wild brown trout,Salmo truttasampled over a two-year period in Clogher Lake in the west of Ireland. Overall prevalence of the parasite was 86% and the mean abundance was 53 worms per fish. Despite the presence of large numbers of worms in the trout very few females (2%) attained full reproductive maturity. This suggests that trout is an accidental host. A sample of yellow eels,Anguilla anguillawas examined at a different time from the same lake. The prevalence ofA. clavulawas 97% and the average abundance was 8 worms per fish. In contrast to the situation in trout, the proportion of female worms attaining full reproductive maturity was 61% fulfilling the expected characteristic of a preferred definitive host. The possible explanations for the very high abundance ofA. clavulain trout are discussed and include the influence of fluctuations in host populations, host diet and the absence of a potential competitor.

scholarly journals The response of North Atlantic diadromous fish to multiple stressors, including land use change: a multidecadal study

2016 ◽  
Vol 73 (12) ◽  
pp. 1759-1769 ◽  
Author(s):  
Elvira de Eyto ◽  
Catherine Dalton ◽  
Mary Dillane ◽  
Eleanor Jennings ◽  
Philip McGinnity ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
North Atlantic ◽  
Salmo Trutta ◽  
Multiple Stressors ◽  
Ecosystem Approach ◽  
Data Sets ◽  
Diadromous Fish ◽  
The North ◽  
The Impact

Reduction of freshwater habitat quality due to land use change can have major impacts on diadromous fish. Partitioning this impact from other potential drivers, such as changing marine conditions and climate, is hampered by a lack of long-term data sets. Here, four decades of data were used to assess the impact of land use change on Salmo salar and anadromous Salmo trutta in the Burrishoole catchment, Ireland, one of the few index sites for diadromous fish in the North Atlantic. Land use change was found to have no significant impact on the freshwater survival of either salmon or trout. However, climate impacted significantly on the survival of salmon and trout in fresh water, with poor survival in years with wetter, warmer winters, coinciding with positive North Atlantic Oscillation values. Additionally, cold springs were associated with higher survival in trout. The addition of hatchery fish into the salmon spawning cohort coincided with low freshwater survival. Our results highlight the necessity for a broad ecosystem approach in any conservation effort of these species.

scholarly journals Fishery and Aquaculture Relationship in the Mediterranean: Present and Future

2003 ◽  
Vol 4 (2) ◽  
pp. 125 ◽  
Author(s):  
G. RELINI
Keyword(s):  
Anguilla Anguilla ◽  
European Eel ◽  
Total Catch ◽  
Sharp Drop ◽  
Fishing Activity ◽  
Marine Fauna ◽  
Marine Research ◽  
The World ◽  
The Mediterranean ◽  
Aquaculture Production

Although the Mediterranean represents only 0.8% of the world seas, it is the site of a very long-established fishing activity, characterized mainly by multispecific catch and by artisanal or coastal activity, resulting from a mosaic of very diversified structures and gears, along more than 45,000 km of coastline. Two main biological features of this sea are the occurrence of a large richness of species (it represents 5.5% - 7% of world marine fauna and 16.6% of macrophyta), which stands in contrast with its ‘trophic poverty’ and the absence of large monospecific fishery, except for some small and large pelagic fish. Another biological characteristic of Mare Nostrumis the high invasion of exotic species, some exploited by fishery and aquaculture, some others quite dangerous. For the entire Mediterranean and Black Sea, the production (catch + aquaculture) had been steadily increasing over the period 1972-1988 from 1,140,000 t to 2,080,000 t . The period 1988-1991 has shown a drastic drop in catches (in 1991: 1,400,000 t). From 1990 to 1995 the total catch increased to 1,701,379 t then decreased and in 2000 reached 1,485,046 t . In 2000 Turkey had the first place with 496,174 t, 26.9% of the total value (1,846,026 t, including fishing and aquaculture), followed by Italy with 25%, Greece 9%, Spain 7.6% and Algeria 5.4%. As in many parts of the world, aquaculture production in the Mediterranean is rapidly expanding. In 1970 the total aquaculture production was about 18,297 t of which 74.3% produced in Italy. In 2000 a value of 358,614 t was reached, about 1/4 of the total fishery catch, while the world aquaculture production corresponds to half of the world total catch. Italy is still the main producer with 46.7% , followed by Greece with 21.5%, Turkey 9.9% and France 6.7%. A sharp drop in the production of the European eel ( Anguilla anguilla) and of the European flat oyster ( Ostrea edulis) is recorded. Positive and negative interactions between fishery and aquaculture are described for environment, food, juveniles, breeders, discards and market. Special attention is devoted to tuna farming, artificial reef and vallicultura. The response of governments and decision makers to the results and suggestions from marine scientists, proposals for urgent action in order to succeed sustainability and priority marine research areas are briefly described. Some urgent needs are outlined.

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