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Ekologija / Ecology

ISSN 0235-7224
ISSN 2029-0586 (online)

2009 m. Nr. 3-4

Impact of environmental conditions on smelt catch fluctuations in the Nemunas River and the Curonian Lagoon
Arvydas ŠVAGŽDYS

The current article presents statistical data on smelt catches in the Curonian Lagoon and the lower reaches of the Nemunas River for the 1927–2006 period and biological indices of spawners for the period 2002–2006. The impact of natural conditions on the efficiency of smelt fishery and catches in the second half of the 20th century as well as the plausible causes of stock fluctuation are analysed. It was ascertained that during the last four decades of the 20th century smelt catches were flood date-dependent. Also, smelt stock reproduction and generation size were found to be favourably affected by late spring, i.e. low water discharge and low air temperature in March. A great abundance of cods in the Baltic Sea had a depressive impact on smelt stock. Meanwhile, an increase in stocks of sander and smelt was recorded in the same year. The analysis of long-term data allows us to propose that fluctuations in smelt stock and catches are climate change-related. The following regularity was observed in Lithuania over several decades of the second half of the 20th century: a period of severe winters was succeeded by that of mild winters every four years. Abundant generations of smelt were formed during late, watery, warm springs. An early, long and cold spring to come after four years enabled fishermen, especially those of the Kaliningrad Region, to make maximum use of the stock.

Keywords: smelt, the Curonian Lagoon, stock, catches, reproduction conditions

Issues:

2011 - Vol.57
No. 1, No. 2

2010 - Vol.56
No. 1-2, No. 3-4

2009 - Vol.55
No. 1, No. 2, No. 3-4

2008 - Vol.54
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2005
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2004
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2003
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2002
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2001
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