Spatial variability in the population structure of the Carcinus aestuarii in Varano lagoon

Abstract

1 - This study analyses some aspects of Carcinus aestuarii biology within the project MOLEVAR (Pilot Project For The Production Of Moleche (C. aestuarii): New Economy For Varano Lagoon) funded by FEP-Puglia 2007-2013 (European Funds for Fishing) in order to evaluate the crabs, Carcinus aestuarii, as a new economic resource for Varano Lagoon (Southern Italy).
2 - The Varano lagoon is located on the Northern coast of the Gargano Promontory (Southern Adriatic Sea). The lagoon and the neighboring coastal area are exploited by mussel farming, although such activity was recently reduced within the lagoon, where the fishery is now the most important resource.
3 - The population structure of C. aestuarii will be studied in three different sites of the Varano lagoon. A total of 205 specimens were obtained from May to December 2012; 192 males and 13 females were observed. Length (CL) and width (CW) of the carapace and total weight (TW), were determined sex ratio. The overall sex ratio was in favor of males (χ2= 11.08). At the same time, water temperature, salinity, were measured with a multiparametric probe.
4 - The ovigerous females (n=2) were caught only December in Capojale site. The catches highest (n=46) were recorded in June month in the Capojale site. The highest abundance was found during June 2012 (44 males and 2 females) of which 23 in Capojale, 22 in Varano and 1 specimen in San Nicola Imbuti station, respectively.
5 - The information on the abundance, life cycle and functional role of this crab is still lacking for Varano lagoon. The data so far do not allow us to have a complete picture of the dynamics of the population, especially because it lacks most of the female component.