Coştei Hydrographic Diversion Node, a Historical Environment Quality and Biological Resources Accessibility Game Changer; Anthropogenic Induced Problems and Sustainable Solutions ‒ An Ichthyologic Perspective

26 fish species were affected by the Coştei historical diversion hydrotechnical system build in 1758. In order to mitigate the negative effects produced by this hydrotechnical work on the fish, a migration system, of nature-like meandering by pass type was proposed. The dimensions of this channel and the slope of about 2% allow fish, and other aquatic organisms to move upstream and downstream of the spillway.

Fish Fauna of Ilisu Area on the Tigris River, Before Impoundment of the Ilisu Dam (Turkey)

The Ilisu Dam is a large hydroelectric power plant that started to collect water in 2019 on the Tigris River in Turkey. This study was done during the period 2010 to 2014 to determine fish fauna of the Tigris River and its tributaries related to the potential reservoir area of the Ilisu Dam before its foundation. 35 fish species belonging to 10 families have been identified in the main river and its tributaries to be covered by the dam reservoir. One of these species, Glyptothorax steindachneri was recorded for the first time from the Turkish part of the Tigris River. 22 species were found widely distributed. At least 16 species were found to be endemic to the Tigris and Euphrates basins. Three species were already recommended with some level of international protection as per IUCN Red List. Cobitis kellei and Paraschistura chrysicristinae species, whose type localities were reported as upper Tigris, were not recorded.

Ecological conditions of the Waterchestnut (Trapa natans L.) in the Danube Delta (Romania)

The diversity of water body types in the Danube Delta offers appropriate ecological niches for the colonisation of frequently large stands of the waterchestnut (Trapa natans). Their phytocoenoses were observed in slowly running and standing waters from clear, sediment-poor, to turbid and sediment-rich waters on muddy ground. Trapa natans occurs in standing, and slowly running, waters and is well adapted to fluctuation of water level changes. The water dynamics is responsible for the composition of accompanying species of the phytocoenoses. The particular zonation, demonstrated by a cross section shows the adaption to the structure and the water flow of certain water bodies. Comparing older and newer research data, a decline of the populations of waterchestnuts became visible.

A Study on Phyto-Chemical Analysis and Antibacterial Activity of Spices on Pathogenic Bacteria Isolated from Commercially Important Edible Marine Fishes, Euthynnus Affinis (Cantor), Katsuwonus Pelamis L. and Auxis Thazard (Lacepede) (Family Scombridae)

Ten bacterial species were isolated and monthly variations in their count were recorded from three edible tuna fishes. Phytochemical analysis and antibacterial activity of hexane, chloroform, methanol, and distilled water extracts of twelve common spices, against the isolated bacteria were evaluated. The study indicates that these pathogenic bacteria in all three tuna fish species cause various human health problems upon consumption.

Plants, Mosses, Charophytes, Protozoan, and Bacteria Water Quality Indicators for Assessment of Organic Pollution and Trophic Status of Continental Water Bodies

This paper presents data compilation for indicator species of organic pollution and trophic state of continental waters. Information was collected from research papers, monographs, electronic resources, and our research. Altogether 316 species of higher plants, plants, mosses, charophytes, protozoan, and bacteria from 11 taxonomical phyla are represented with ecological preferences for saprobity indicators with saprobity index (S) and indicators of trophic state. This comprehensive data can be used for the purpose of aquatic ecosystem assessment and monitoring of water quality based on bioindication methods.

Cladocera from the Sediment of High Arctic Lake in Svalbard (Norway)

The High Arctic Region’s freshwater ecosystems serve as hot spots to study the impact of extreme warming conditions on the biota. The cladoceran remains have been recovered from the surface sediments of a non-marine water body near Ny-Alesund, Svalbard, Norway. The cladoceran (crustaceans) belongs to the Chydorus sphaericus group Frey, 1980 and Daphnia pulex Leydig, 1860. The ecology of the species suggests that they lived in a well-developed ecosystem with Water Quality Class 3. This study has implications for understanding the response of the present-day biota experiencing the changing climate conditions and using these remains for assessing palaeoenvironmental conditions.

Histological Study of the Immune System in Zebrafish, Danio Rerio (Hamilton, 1822)

The aim of the present study was to investigate the cellular characteristics of the immune tissues of Zebrafish, Danio rerio (Hamilton, 1822). The fish were fixed in Bouin՚s solution for 24 hours then dehydrated, cleared, paraffinized, embedded and finally sectioned, stained and observed through optical microscopy. Results showed that immune system tissues of Zebrafish include the apical part of the kidney, thymus, and spleen. The apical part of the kidney was composed of hematopoietic tissue containing blood and immune cells. The spleen was a single organ located at the abdominal cavity containing melanomacrophages. The thymus was observed as a paired organ at the posterior part of the branchial cavity. Results showed that the immune system of the Zebrafish was dispersed in several organs of the body and that this species could be used as a laboratory model organism in immune system studies.

Some Aspects of the Growth Features and Condition Factor of Arius Gigas (Boulenger, 1911) from Obuama Creek (Rivers State, Nigeria)

Length-frequency distributions, length-weight relationships, length-length relationships and condition factors (Fulton’s KF, allometric KA, and relative KR) of Arius gigas in the Obuama Creek in Rivers State, Nigeria were investigated. 217 samples were collected from artisanal fishermen fishing on the Obuama Creek from March to September 2019. The parameter b of the length-weight relationship was 2.52 indicating negative allometric growth. The KF ranged from 0.51 to 2.03 with a mean value of 0.85 ± 0 while the overall low values of KR and KA, in this study are generally a characteristic of fish in poor health. This study provides basic information on some of the biological features of A. gigas which should be useful for facilitating management strategies and regulations of the stocks.

A Study on Marine Fishery Resources of Andhra Pradesh: Ecological Aspects and Morphometrics of Common Marine Fishes of Visakhapatnam ‒ Protein Content and Bioaccumulation of Heavy Metals in Pomfret Fish Species

212 marine fishery resources were recorded in the waters of Andhra Pradesh State. Morphometric data was provided for 20 edible fishery resources landing at the fishing harbour of Visakhapatnam. The harbour area is polluted due to influx of various industrial effluents and domestic sewage. In Pampus argenteus, P. chinensis and Parastromateus niger, the total protein content is 16.24-19.58%. Further, arsenic concentration in muscle and gill portions individually or combined in all three of the species is highly negligible. Cadmium, mercury, and lead levels in the muscle and gills of these species are within or slightly above the recommended limits set by EU (2006) and FAO (2003), FAO/WHO (2011), MAFF, and FSSAI (2011) indicating that the consumption of these fishes is not harmful.

Reproductive Biology of the Tigris Scraper, Capoeta Umbla (Heckel, 1843) Population Living in Solhan Creek of Murat River (Bingöl, Turkey)

We studied the reproductive traits in 23 of 190 individuals of Capoeta umbla caught monthly in the Solhan Creek of the Murat River between April 2017 and March 2018. The sex ratio (F:M) was found to be 1:1.11. The macroscopic examination of the gonads and gonado-somatic index indicated that the reproductive period lasted from May to August with peak activity in May. The fecundity ranged from 2,000 to 9,000 oocytes, and it correlated with the total length and body weight. This work represents the first attempt to investigate the reproductive traits of the Capoeta umbla population in the Solhan Creek. The results provide information on the reproductive biology and contribute to the conservation of the fish population and its sustainable management.