Effects of the Great East Japan Tsunami on Fish Populations and Ecosystem Recovery. The Natori River; Northeastern Japan

2016 ◽  
pp. 201-216 ◽  
Author(s):  
Kinuko Ito ◽  
Ayu Katayama ◽  
Kazunori Shizuka ◽  
Norihiro Monna
Keyword(s):  
Fish Populations ◽  
Ecosystem Recovery ◽  
Northeastern Japan

Nutrients in Salmonid Ecosystems: Sustaining Production and Biodiversity

2003 ◽  
Keyword(s):  
Ecosystem Function ◽  
Fish Populations ◽  
Alternative Methods ◽  
Ecosystem Productivity ◽  
Ecosystem Recovery ◽  
Current Management ◽  
Stream Flows ◽  
Riparian Habitats ◽  
Productivity Potential ◽  
Salmon Carcasses

<em>Abstract.</em>—Based on the information presented at the Restoring Nutrients to Salmonid Ecosystems conference in Eugene, Oregon, in April of 2001, it will be necessary to substantially increase and achieve salmon spawner escapement goals in order to meet ecosystem productivity potential. Modeling of recovery rates shows that achievement of even the currently identified spawner escapement goals (much less ecosystem recovery) in less than 50–100 years is unlikely, unless there are substantial shifts in management thought and practice. To speed recovery, it is necessary to achieve consistent rates of increase in spawning escapement not seen in current management activities. Until actual spawner escapements approach levels necessary to support ecosystem function, it will be necessary to utilize alternative methods such as the distribution of salmon carcasses, carcass analogs, or the use of fertilizer to provide the nutrients needed to assist its salmonid population recovery. In addition to restoring absolute numbers, the size and age structures of the fish populations need to be restored in order to successfully utilize the available environment. Simply increasing escapements and resultant nutrient levels, however, is insufficient. Stream flows, whether average, flood, or low, need to be stabilized. Instream and riparian habitats need to be stabilized and restored; this would include allowing normal flood paths to be followed.

The concept of local explosion in freshwater ecosystems

2013 ◽  
Vol 25 (1-2) ◽  
pp. 136-148
Author(s):  
I. V. Gryb
Keyword(s):  
Species Composition ◽  
Aquatic Environment ◽  
Arid Zone ◽  
Fish Fauna ◽  
River Basins ◽  
Freshwater Ecosystems ◽  
Human Society ◽  
Living Matter ◽  
Ecosystem Recovery ◽  
Average Temperature

The concept of an explosion in freshwater ecosystems as a result of the release of accumulated energy, accompanied by the destruction of the steady climax successions of hydrocenoses is presented. The typification of local explosions as well as methods for assessing their risk during the development of river basins are shown. The change in atmospheric circulation, impaired phases of the hydrological regime of rivers, increasing the average temperature of the planet, including in Polesie to 0,6 ºC, deforestation leads to concentration and release of huge amounts of unmanaged terrestrial energy, which manifests itself in the form of disasters and emergencies. Hydroecological explosion is formed as a result of multifactorial external influence (natural and anthropogenic) on the water body in a certain period of time. Moreover, its level at wastewater discharge depends on the mass of recycled impurities and behaved processing capacity of the reservoir, and the mass of dumped on biocides and the possibility of the water flow to their dilution and to the utilization of non-toxic concentrations. In all these cases the preservation of "centers of life" in the tributaries of the first order – local fish reproduction areas contributed to ecosystem recovery, and the entire ecosystem has evolved from equilibrium to non-equilibrium with further restructuring after the explosion and environmental transition to a new trophic level. It means that hydroecological explosion can be researched as the logical course of development of living matter in abiotic environmental conditions, ending abruptly with the formation of new species composition cenoses and new bio-productivity. The buffer capacity of the water environment is reduced due to re-development and anthropic transformation of geobiocenoses of river basins, which leads to a weakening of life resistance. This applies particularly to the southern industrial regions of Ukraine, located in the arid zone that is even more relevant in the context of increased average temperature due to the greenhouse effect, as well as to Polesie (Western, Central and Chernihiv), had been exposed to large-scale drainage of 60-80th years, which contributed to the degradation of peatlands and fitostroma. Imposing the western trace of emissions from the Chernobyl accident to these areas had created the conditions of prolonged hydroecological explosion in an intense process of aging water bodies, especially lakes, change in species composition of fish fauna and the occurrence of neoplasms at the organismal level. Under these conditions, for the existence of man and the environment the vitaukta should be strengthened, i.e. buffer resistance and capacitance the aquatic environment, bioefficiency on the one hand and balanced using the energy deposited - on the other. This will restore the functioning of ecosystems "channel-floodplain", "riverbed-lake", reducing the energy load on the aquatic environment. Hydroecological explosions of natural origin can not be considered a pathology – it is a jump process of natural selection of species of biota. Another thing, if they are of anthropogenic origin and if the magnitude of such an impact is on the power of geological factors. Hydroecological explosions can be regarded as a manifestation of environmental wars that consciously or unconsciously, human society is waging against themselves and their kind in the river basins, so prevention of entropy increase in the aquatic environment and the prevention of hydroecological explosions is a matter of human survival. While the man - is not the final link in the development of living matter, it can develop without him, as matter is eternal, and the forms of its existence are different.

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