Intrinsic processes causing periodic changes in stability in a shallow biomanipulated lake

2011 ◽  
Vol 62 (2) ◽  
pp. 197 ◽  
Author(s):  
István Tátrai ◽  
Ágnes I. György ◽  
Kálmán Mátyás ◽  
János Korponai ◽  
Piroska Pomogyi ◽  
...  
Keyword(s):  
Food Web ◽  
Shallow Lakes ◽  
Nutrient Loading ◽  
Fish Biomass ◽  
Alternative States ◽  
Fish Manipulation ◽  
Water State ◽  
Benthic Fishes ◽  
Turbid State

Shallow lakes experience alternative states in their biotic organisation over time. In this study, we analysed a long-term dataset on the recovery from eutrophication of a shallow hypertrophic lake (Lake Major, Hungary) following fish manipulation. Disturbances in the food web triggered a shift, markedly affecting both abiotic and biotic variables. Clear and turbid states of Lake Major over the period 1999–2009 were defined by concentrations of chlorophyll-a. Lake Major in a clear-water state had higher transparency and submerged macrophyte cover, lower turbidity and fish biomass, and total phosphorus was relatively low compared to that shown during the turbid-water state. It follows from our study that a regime shift from a turbid state to a clear state can be expected in response to fish manipulation. Reduction in fish biomass increases light conditions, decreases internal nutrient loading and promotes macrophyte dispersion. Food-web effects appear to be considerable in these shallow lakes containing benthic fishes. The roles of phosphorus and submerged macrophytes are essential in maintenance of alternative states of vegetation in shallow lakes of various climatic zones.

Food-web manipulation in a small, eutrophic Lake Wirbel, Poland: long-term changes in fish biomass and basic measures of water quality. A case study

1997 ◽  
pp. 383-386 ◽  
Author(s):  
Andrzej Prejs ◽  
Joanna Pijanowska ◽  
Paweł Koperski ◽  
Andrzej Martyniak ◽  
Sławomir Boroń ◽  
...  
Keyword(s):  
Water Quality ◽  
Food Web ◽  
Eutrophic Lake ◽  
Fish Biomass ◽  
Long Term Changes

scholarly journals Responses of the fish community in a eutrophicated lake to long-term food web management assessed by multiple sampling methods

Hydrobiologia ◽  
2020 ◽  
Vol 847 (21) ◽  
pp. 4559-4573 ◽  
Author(s):  
Martti Rask ◽  
Tommi Malinen ◽  
Mikko Olin ◽  
Heikki Peltonen ◽  
Jukka Ruuhijärvi ◽  
...  
Keyword(s):  
Food Web ◽  
Fish Community ◽  
Population Analysis ◽  
Abundant Species ◽  
Fish Growth ◽  
Fish Biomass ◽  
Fish Community Structure ◽  
Web Management ◽  
White Bream

AbstractFish community responses to long-term mass removal of planktivorous fish from eutrophicated Lake Tuusulanjärvi were examined during 1996–2018 by gill net test fishing, hydroacoustics with simultaneous trawling, virtual population analysis (VPA) and fish growth measurements. The gillnet catches of white bream and roach increased first while bream and bleak decreased but recovered in the early 2000s. Perch and pikeperch increased but ruffe decreased and remained low. According to hydroacoustics, pelagic fish biomass decreased. Smelt was the most abundant species at the beginning and the end of the monitoring period but bream dominated the fish biomass in most years. VPA calculations indicated a five- and threefold increase in the biomass of bream and white bream, respectively, during 2005–2011. Significant increases appeared in the growth of perch, bream and roach. Overall, the responses in the fish community structure and fish abundance to the food web management were slight and mostly masked by changes in reproduction and growth of fish and annual variability in environmental conditions such as temperature and water turbidity. Gillnet test fishing and echo sounding complemented each other well in monitoring the effects of management fishing. Where bream is one of the dominant species VPA is also recommended.

Land conversion regulates the effects of long-term climate warming on soil micro-food web communities

2021 ◽  
Vol 314 ◽  
pp. 107426
Author(s):  
Pingting Guan ◽  
Mohammad Mahamood ◽  
Yurong Yang ◽  
Donghui Wu
Keyword(s):  
Food Web ◽  
Climate Warming ◽  
Land Conversion ◽  
Web Communities

Long-term vegetation restoration promotes the stability of the soil micro-food web in the Loess Plateau in North-west China

CATENA ◽  
2021 ◽  
Vol 202 ◽  
pp. 105293
Author(s):  
Yang Wu ◽  
WenJing Chen ◽  
Wulan Entemake ◽  
Jie Wang ◽  
HongFei Liu ◽  
...  
Keyword(s):  
Food Web ◽  
Loess Plateau ◽  
Vegetation Restoration ◽  
The Loess Plateau ◽  
West China ◽  
North West ◽  
The Stability

scholarly journals A long-term, spatially replicated experimental test of the effect of marine reserves on local fish yields

2005 ◽  
Vol 62 (1) ◽  
pp. 98-108 ◽  
Author(s):  
Angel C Alcala ◽  
Garry R Russ ◽  
Aileen P Maypa ◽  
Hilconida P Calumpong
Keyword(s):  
Coral Reefs ◽  
Experimental Test ◽  
Marine Reserves ◽  
Fish Biomass ◽  
Total Catch ◽  
Target Fish ◽  
Fish Yields

Do no-take marine reserves affect fishery yields? Manipulations of reserve status, and yield estimates, were made at two Philippine islands over two decades. Twenty-five percent and ten percent, respectively, of the coral reefs at Sumilon and Apo islands were made no-take reserves in 1974 and 1982. Biomass of target fish increased inside the no-take reserves 3- to 4.5-fold over 9–18 years. Biomass did not increase outside each reserve. Protection of the Sumilon reserve ceased in 1984. Biomass of targeted fish in the reserve and trap and gillnet catches of these fish declined by 42.7% and 40%, respectively, by 1985. The reserve was reprotected from 1987 to 1991 and from 1995 to 2001. Fish biomass increased in the reserve by 27.2%. Trap and gillnet catches outside the reserve increased 26.9% by 2001. The Apo reserve was protected from 1982 to 2001. Total catch of major fish families was significantly higher after (1985–2001) than before (1981) reserve establishment at Apo, increasing 41.3% between 1981 and 1998–2001. These experiments, plus spillover evidence, suggest that marine reserves may help maintain, or even enhance, local fishery yields in the long-term.

scholarly journals Projecting marine fish production and catch potential in Bangladesh in the 21st century under long-term environmental change and management scenarios

2015 ◽  
Vol 73 (5) ◽  
pp. 1357-1369 ◽  
Author(s):  
Jose A. Fernandes ◽  
Susan Kay ◽  
Mostafa A. R. Hossain ◽  
Munir Ahmed ◽  
William W. L. Cheung ◽  
...  
Keyword(s):  
Climate Change ◽  
21St Century ◽  
Low Income ◽  
Nutrient Loading ◽  
Global Climate Model ◽  
Productive Capacity ◽  
Fish Production ◽  
Management Scenarios ◽  
Bombay Duck

Abstract The fisheries sector is crucial to the Bangladeshi economy and wellbeing, accounting for 4.4% of national gross domestic product and 22.8% of agriculture sector production, and supplying ca. 60% of the national animal protein intake. Fish is vital to the 16 million Bangladeshis living near the coast, a number that has doubled since the 1980s. Here, we develop and apply tools to project the long-term productive capacity of Bangladesh marine fisheries under climate and fisheries management scenarios, based on downscaling a global climate model, using associated river flow and nutrient loading estimates, projecting high-resolution changes in physical and biochemical ocean properties, and eventually projecting fish production and catch potential under different fishing mortality targets. We place particular interest on Hilsa shad (Tenualosa ilisha), which accounts for ca. 11% of total catches, and Bombay duck (Harpadon nehereus), a low price fish that is the second highest catch in Bangladesh and is highly consumed by low-income communities. It is concluded that the impacts of climate change, under greenhouse emissions scenario A1B, are likely to reduce the potential fish production in the Bangladesh exclusive economic zone by <10%. However, these impacts are larger for the two target species. Under sustainable management practices, we expect Hilsa shad catches to show a minor decline in potential catch by 2030 but a significant (25%) decline by 2060. However, if overexploitation is allowed, catches are projected to fall much further, by almost 95% by 2060, compared with the Business as Usual scenario for the start of the 21st century. For Bombay duck, potential catches by 2060 under sustainable scenarios will produce a decline of <20% compared with current catches. The results demonstrate that management can mitigate or exacerbate the effects of climate change on ecosystem productivity.

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