Body size and reproductive traits of Palaemon elegans Rathke, 1837 (Crustacea, Decapoda), a recent colonizer of the Baltic Sea

Abstract

Palaemon elegans is a species of prawn new (since 2000) to the southern Baltic. The aim of this study was to find out whether there are differences in the sizes of individuals and in the reproductive traits of P. elegans inhabiting different areas of the southern Baltic Sea and to compare the data obtained with existing data for populations from other coastal areas. The present study was carried out in the summers of 2005 and 2007 in three areas differing in their hydrological conditions (primarily in salinity): Puck Bay (PB), the Vistula Delta (VD) and the Vistula Lagoon (VL), Poland. The maximum body lengths of these prawns (females = 60 mm, males = 41 mm), and body masses (1201 mg and 533 mg respectively) found in the southern Baltic were less than those reported from many other parts of the geographical range of this species. The increase in body mass with length was the smallest in the prawns inhabiting VL, and the maximum lengths they grew to were also shorter (females -52 mm and males -39 mm) than in PB. The numbers of eggs carried by P. elegans in the southern Baltic were smaller than those found in females in its native regions. Differences were also found in the numbers and sizes of eggs between prawns inhabiting different locations in the southern Baltic. It was concluded that the low salinity of the southern Baltic Sea (even below 7 PSU), while not preventing this prawn from reproducing, caused a shift to the production of fewer but larger eggs. The reproductive strategy that Baltic populations of P. elegans has adopted is one of the factors responsible for its very rapid and large-scale colonization of the southern Baltic Sea.

Growth and reproductive biology of the amphidromous shrimp Palaemon pandaliformis (Decapoda: Caridea) in a Neotropical river from northeastern Brazil

“…BilGin & Samsun (2006: see table 7, for review) and Janas & Mańkucka (2010: see table 3, for review) compared increases in the change of egg diameter of marine Palaemonids and found the same pattern recorded in this study. AnDerson (1982) states that an increase of the long axis is caused by growth of embryonic structures in the cephalic-caudal axis.…”

Study of the growth, reproductive biology and abundance for invasive shrimps Palaemon elegans Rathke from Garmat Ali river Basrah, Southern Iraq

“…Thirty two of ovigerous females were put into the 30 x 30 x 15 cm aquarium individually to observe the eggs development [4], brackishwater was supplied and the water was exchanged twice a day until hatching [13].…”

“…elegans is characterized by open habitats [3], usually in the tidal zones, on sandy bottoms covered with macroalgae, bare sandy sea beds, the brown algae belt and stony bottoms [4][5][6][7].…”

First record of the oriental shrimp Palaemon macrodactylus M. J. Rathbun, 1902 in the Baltic Sea

“…The Baltic prawn Palaemon adspersus Rathke, 1837 occurs almost in the entire Baltic Sea, including some parts of the Gulf of Bothnia and the Gulf of Finland (Janas et al 2013, Katajisto et al 2013. The rockpool prawn Palaemon elegans Rathke, 1837 was recorded only occasionally in the western Baltic until the 1990s (Köhn & Gosselck 1989), but in the early 21 century, the species colonized the southern and the north-eastern Baltic Sea on a large scale (Janas et al 2004, Grabowski 2006, Janas & Mańkucka 2010, Katajisto et al 2013). This colonization was most probably a result of human introduction (Reuschel et al 2010).…”