DBPapers
DOI: 10.5593/SGEM2016/B32/S15.116

THE STATE OF SPRAT (Sprattus sprattus, LINNAEUS 1758) POPULATION IN THE ROMANIAN MARINE AREA, ITS IMPORTANCE IN LOCAL ECONOMY AND AS PREY FOR LARGER FISHERIES

A. Totoiu, M. Galatchi, C. Danilov, F. Timofte, G. Radu
Wednesday 7 September 2016 by Libadmin2016

References: 16th International Multidisciplinary Scientific GeoConference SGEM 2016, www.sgem.org, SGEM2016 Conference Proceedings, ISBN 978-619-7105-62-9 / ISSN 1314-2704, June 28 - July 6, 2016, Book3 Vol. 2, 893-900 pp

ABSTRACT
Sprat (Sprattus sprattus, Linnaeus 1758) is one of the key short-lived pelagic species of the Romanian Black Sea area. It reaches maturity at 1 year and reproduces during the whole year, but its peak spawning is between November and March. The recruitment is strongly controlled by winter hydroclimatic conditions and plankton blooms. In spring, schools migrate to coastal waters for feeding. During summer, the juvenile and adult sprat populations leave the upper warm layer and thus avoid severe competition for food with other plankton-consumers including Mnemiopsis leidyi. During this period their preferred food consists mainly of the cold-water Calanus and Pseudocalanus copepods living below the cold intermediate layer of the water column. The reduction of the sprat stock in the early 1990s was partly due to food competition with the Mnemiopsis population outburst. As with the other commercial stocks, heavy overfishing took place before and during the M. leidyi outbreak as well, which aggravated the stock depletion. In addition to M. leidyi, the jellyfish Aurelia aurita distributed in deeper waters has a strong trophic interference with sprat. This may explain the coincidence between the declining phase of sprat recruitment and biomass and the peak abundance of A. aurita during the 1980s. The paper makes an analysis of the status and importance of sprat in the Romanian Black Sea area, focusing on: - Distribution and fishing agglomerations biomass; - Influence of environmental conditions on the status and distribution; - Evolution of biological population parameters; - Dynamics of sprat catches in comparison with the other species in the Romanian marine area; - The importance of sprat in the local economy and in the trophic spectrum of larger fishes.

Keywords: sprat, Romanian Black Sea area, catch, environmental conditions, distribution, biomass, trophic chain