Distribución de los morfotipos gregaria y subrugosa de la langostilla Munida gregaria (Decapoda, Galatheidae) en el golfo San jorge en la campaña de verano AE-01/2011. Integración de resultados con las campañas 2009 y 2010

The objective of this work is to increase knowledge on the distribution and punctual density of both morphotypes of Munida gregaria in the San Jorge Gulf, Argentina. The data derived from the research cruise carried out on board of the FV “Alvarez Entrena I” in February 2011. Specimens of gregaria and subrugosa were caught in 37 and 73 of the 91 trawls performed, respectively. Out of the total of positive trawls, 17 were performed at depths lower than 55 m and the remaining 60 at deeper waters. The relative average abundance of both morphotypes increased significantly with regard to the two previous years (2009, 2010). M. gregaria subrugosa represented 66.4% and gregaria the remaining percentage. In the south sector of the gulf, where the highest punctual density values for both morphotypes were registered, as well as in the north, where both were represented, subrugosa was the most abundant. In both depth strata significant density differences for gregaria and none for subrugosa were found. The sex ratio for gregaria was 1:1 and for subrugosa 2.3:1 (males:females). The punctual density results obtained for the last three years show alternation in the dominance of one morphotype over another and variation in the distribution (north or south of the gulf) of the maximum density values found for each one. In 2009 and 2011 predominance of subrugosa and in 2010 of gregaria was observed. It is recommended to continue studying M. gregaria to better understand the role it plays in the San Jorge Gulf ecosystem.