Typical representatives of the nekton is the herring. It is well known that this fish has great commercial value. Until comparatively recently, it was promyshlyali in such large quantities that its price was very low, despite excellent taste and nutritional quality. In recent years, due to the sharp increase of the fishing fleet and introduction of intensive methods of production occurred overfishing. The number of herring in the oceans have decreased dramatically.
If in the future the intensity of the herring fishery will increase or even remain at current levels in the coming years, this valuable food fish will become a Museum rarity. Reduction of stocks of herring and concerned consumers and fishermen, but the first sounded the alarm scientists.
The appearance of the herring is well known to everyone, but it is unlikely that the layman can easily distinguish one kind of herring from another: the difference between them for the untrained eye to be insignificant. Species differences are not only in the details of the structure and the size of the fish, much deeper than they differ from each other in biology, numbers, distribution. Therefore, the fishery for mackerel fishes should be strictly subordinated to scientific data, to each type needs special approach. Continue reading
Sponges that are sold in stores and are used for washing dishes or cleaning the kitchen, not real. They are made from synthetic materials, although very similar to a real sponge and easy to use.
But these sponges appear in the sea, not in a chemical laboratory. For a long time many were convinced that they know all about sponges. It was believed that this plant, until in 1825 a man by the name of Robert Grant proved that sponges were animals!
It considered the sponge in water through a microscope. And saw trickles of water, which went in through one hole and out through another. Still, for many years, scientists did not know what kind of animal. Thought it was a tiny single-celled creatures that live together in one big colony.
We now know that sponges are the dried skeletons of marine animals belonging to the class of “porous”. This is a pretty significant group of animals. Although sponges are one of the lowest forms in the animal Kingdom, their structure is quite complicated. Continue reading
From 11 to 19 June this year, the State ecological inspection in the Nikolaev area repeatedly documented fish kills in the rivers the southern bug, Ingul and the Bugsky estuary. In this regard, we selected 22 samples of water and held control for the major pollutants.
As reported in a press-state ecoinspection service in the Nikolaev area, in the surface layer recorded water dissolved oxygen for the entire period from 0.9 to 10.5 mg/DM 3. The ratio — during the summer, the oxygen content in all water bodies should be not less than 6,0 mg/dm3 .
The oxygen is released into the water column as a result of processes of photosynthesis, which better takes place in the daytime. At night there is a reverse process. Therefore, the minimum content of oxygen is observed at dawn, which was recorded on June 19, in 6 hours (the water temperature was 25 0 C). The concentration of dissolved oxygen ranged from 4.0 mg/DM 3 the water surface to 0.2 mg/dm3 in the bottom horizon. This fact is due to the hydrometeorological conditions prevailing in the present time, what is the likely cause of the phenomena zamorny. Continue reading