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Abstract

This study determined the optimum thermal conditions to induce gonad maturity in female The aim of the study was to verify which of the three studied water temperatures: 15ºC, 18ºC or 21°C is the most suitable for inducing gonad maturation and reaching maturity by the female European eel. The thermal regime during the period of female eel maturation should be established nearly individually, depending on the degree of maturation of spawners and it should be lower than that proposed until recently. The study found that 15°C is the best temperature to bring females of European eel to maturity. Excessively high temperatures were found to cause accelerated gonad maturation and to result in a lower oocyte quality. Moreover, the fish kept at higher temperatures (18ºC, 21°C) consume their energy resources (for example, for formation of gonads) faster than those kept in water at 15°C. The highest quality was noted for eggs obtained from females kept at lowest tested temperature.

Changes in Cadmium Concentration in Muscles, Ovaries, and Eggs of Silver European Eel (Anguilla anguilla) during Maturation under Controlled Conditions

“…During the experiment, salinity was maintained at the level of 32-35‰. After 20 days, the water was heated to 15 • C (±0.1 • C) as the optimal for eel female maturation under controlled conditions [41]. The circulation had controllable physicochemical conditions (temperature, photoperiod) and the system was equipped with a PolyGeser filter and UV lamps (2 × 36 W each).…”

“…Hormonal stimulation (n = 20) was started after the desired water salinity level was achieved according to the method described by Nowosad et al [33] and Kucharczyk et al [41]. After being taken out of the tanks, the fish were put in a container with an anesthetic.…”

AKTIVITAS TRIPSIN-<em>LIKE</em> DAN KIMOTRIPSIN-<em>LIKE</em> PADA IKAN SIDAT TROPIK <em>Anguilla bicolor</em> McClelland

“…Apabila terjadi perubahan pada pH dan temperatur biasanya secara drastis mempengaruhi kinerja katalitik enzim. Pernyataan tersebut dikuatkan oleh Kucharczyk et al (2016) mengatakan bahwa temperatur merupakan salah satu faktor yang menimbulkan pengaruh yang sangat besar dalam metabolisme seperti pada nutrisi ikan dan pertumbuhannya baik laju pertumbuhan dan ukuran tubuh ikan.…”

Biological Parameters and Spermatogenesis in Razorfish (Pelecus cultratus) Population Inhabiting the Largest Shallow Lake of Central Europe (Lake Balaton): Studies for In Vitro Conservation Purposes

“…Natural populations of the species have significantly declined in several European countries, leading to its protected status in Baltic states (Annex II of the International Association for the Protection of Species of the European Commonwealth of the Baltic States, Fauna Flora Habitat Directive). Additionally, it is classified as critically endangered in Poland according to The Red List of lampreys and fish of Poland (as of 2009); code: CR) [4,[8][9][10][11]. Furthermore, razorfish is listed in the IV Appendix of the EU Bird and Habitat Directive [1,12].…”

“…Furthermore, razorfish is listed in the IV Appendix of the EU Bird and Habitat Directive [1,12]. The regulation of rivers, including activities such as gravel excavation and dam constructions, has resulted in the destruction of natural spawning grounds for the species [10,13,14]. To address these challenges, biotechnological methods, including controlled reproduction, larvae rearing, and gamete preservation can assist in the successful recovery and restoration of the natural populations [5,9,10,15,16].…”