STRUCTURE OF DANUBE SHAD (Alosa pontica Eichwald, 1838) SPAWNER FLOCKS MIGRATING FOR REPRODUCTION IN DANUBE RIVER (MIGRATION OF FISHES IN ROMANIAN DANUBE RIVER N o 2)

Abstract

A Ab bs st tr ra ac ct t. . The main purpose of this paper is to actualize last data on Danube shad (Alosa pontica Eichwald, 1838) migration process in Danube River. This species was widely studied last time in Danube River, but there are still some biological and ecological aspects to be revealed. Study of periodical changes in the total amount of capture and spawners structure could bring more and relevant information on presumed cyclic decrease and increase of stocks and also about the main causes of their interesting population dynamics. We try to examine some other aspects related to the spawning biology as well as to the biometry of different age-classes and also to link these issues to the last changes in environment conditions.

Age, Growth, and Mortality of Pontic Shad, Alosa immaculata Bennett, 1835, in the Danube River, Romania

“…The authors reported that the 6-, 5-, and 3-year-old cohorts represent 19.85%, 15.62%, and 13.14%, respectively, while individuals of 7 and 2 years represent a small part of the migratory population (8.32% and 1.17%, respectively). Other authors [38] report six age groups (from 2-to 7-year-old individuals) for Pontic shad in the Danube River, Romania. In a similar study, Leonov et al (2023) [6] reported different structures of migratory Pontic shad (for the year 2022) at the Danube mouth (Sulina Branch Mm 34-18): the highest percentage of individuals captured were 3 years old (33.33%), followed by 4 years old (26.38%), while only a small percentage (11.11%) were 5 years old and 6 years old (6.94%).…”

Reproducibility of age determination by scale and vertebra in pontic shad (Alosa pontica Eichwald, 1838), from the Danube

“…Pontic shad (Alosa pontica Eichwald, 1838) is an economically important fish species which is highly appreciated by a certain number of consumers in the Lower Danube Region because it is the Christian custom of local people to eat Pontic shad during Lent (Ciolac and Patriche, 2004). Pontic shad stocks in the Black Sea and Danube River have decreased mainly due to overfishing and pollution (Navodaru, 1996;Navodaru and Waldman, 2003).…”

Ecological and toxicological study of the Pontic shad (Alosa immaculata Bennett, 1835) in the Danube river in Serbia

“…Crnomorska haringa je komercijalno značajna riblja vrsta u delti Dunava. U zemljama donjeg podunavlja (Rumunija, Ukrajina i Bugarska) visoko je cenjena od strane određenog broja stanovnika koji tokom hrišćanskih praznika ovu vrstu obilato konzumiraju, naročito za vreme Velikog posta (Ciolac & Patriche, 2004).…”

“…174,0 30,6 6 (5) 4 1 27 37 380 5,227 8,750 0,284 4,545 0,170 0,398 50,2 730,9 2,557 51,2 0,0 28 37,5 452 5,968 6,694 0,242 3,629 0,161 0,323 26,0 295,6 0,726 35,0 0,0 29 37,5 395 4,545 11,091 0,318 6,818 0,273 0,273 57,5 873,7 2,409 60, (Kolarov 1985;Navodaru 1998;Navodaru et al 2001;Navodaru & Waldman, 2003;Ciolac, 2004;Ciolac & Patriche, 2004). Cren, 1951;Brown, 1957;Tesch, 1971).…”