Terrestrial and semiaquatic arthropods
As regards the terrestrial and semiaquatic arthropods, no information is available for the period before the dyking. But from the knowledge available from existing natural biotopes one may draw conclusions and distribution of these animal species (insects, spiders and other arthropods groups) and communities.
In areas adjacent to the Danube Delta where no major alterations have occurred, original bioceonoses have been presented.
Under natural conditions the Danube Delta offered an excellent habitat to a number of freshwater fish, particularly to cyprinids which were almost constantly present on the islands. For other fish the islands were only spawning and feeding sites. During the spring floods of the Danube, when the broad reed areas were inundated, huge schools of short distance migratory visited the spawning sites of the islands.
Sample fishing, carried out more than two decades before the dyking (1963), proved great abundance of carps (Carassius carassius) in calm, muddy and reed-covered waters. This species, which is well adapted to fluctuating oxygen contents in the water and periods of extremely shallow waters, had an advantage compared to other species.
Other significant species were pike (Esox lucuis), red eye (Scardinius erythrophthalamus), roach (Rutilus rutilus carpathorossicus) as well as carp (Cyprinus carpio), catfish (Ssilurus glanis), pikeperch (stizostedion lucioperca), bream (Abramis brama), barbell (Barbus barbus), orfe (Leucuscus idus), asp (Aspius aspius), tench (Tinca tinca), white bream (Blicca bjoerkna) and perch (Perca flubiatilis).
Even though considerable fish stands of economically valuable species existed on both island, they were not used commercially but for the personal requirements of the local populations.
The Danube Delta offers breeding, feeding and resting places to large populations of approximately 300 bird species and is known as a veritable paradise for birds. Nevertheless, the summary data on avifauna was first published in the 1960s, with a list comprising 109 nesting birds and 59 migratory birds. This list is being constantly updated as are the assignments of the Danube Delta’s bird species to certain aquatic, amphibious and terrestrial habitats. Ecological representation of the delta’s fauna is also updated.
The surface area covered by reed offered breeding and nesting places to numerous bird species. Open waters and temporarily inundated muddy banks were used as feeding and resting places by many waders and marsh birds. On the whole, the species of the island area may be assigned to various aquatic, semiaquatic and terrestrial habitats.
Only a few mammals' species were represented although with a very high density compared to their current presence and density in the Delta. Some of them were of great hunting interest. We could find the following species: otter (Lutra lutra), mink (Mustela lutreola), ermine (Mustela erminea aestiva), wild boar (Sus scrofa), fox (Vulpes vulpes melanogaster), deer (Caprelous caprelous), common hare (Lepus europaeus), raccoon dog (Nyctereutes procynoides), muskrat (Ondatra zibethica) and nutria (Myocastor coypus).
SOURCE : IBIS TOURS BIRD-WATCHING SPECIALISTS