In 2006 an unusual find of Procambarus clarkii, today considered one of the most dangerous exotic crayfish, was made within the preserved brackish Mediterranean biotope ''Palude di Torre Flavia'' (Rome, Italy). Here the investigation on the population structure and dynamics of P. clarkii inhabiting this brackish wetland is presented in an attempt to describe the life history pattern in this type of habitat. The present study showed that this species has a lower growth rate and higher longevity than other studied European P. clarkii populations, and that it can damage brackish habitats and human livelihoods. The main results of this study chiefly concern the differences found between several lifehistory parameters of the studied population and those obtained in previous studies. These results showed the high ecological plasticity of P. clarkii, indicate the need to intervene before the species spreads further in brackish water, for the conservation of Mediterranean coastal habitats.

In this study some reproductive aspects of Potamon fluviatile are described. Data were obtained by studying the gonad structure of both sexes using histological methods. The ovary consists of a pair of long, sac-like organs, with a thin ovarian wall surrounding the oocytes and eggs. The ovarian epithelium creates several oogenetic pouches containing growing oocytes and mature eggs, while oogonia are concentrated in a germarium within the ovarian lumen. Eggs are ovulated from the oogenetic pouches into the central ovarian lumen, transferred into the oviduct, and fertilized with sperm stored in the spermatheca. The male reproductive system consists of paired testes, united by a commissure, and genital ducts. Gametes leave the testicular tubules and reach the proximal region of the vas deferens, where the epithelium shows secretory activity. RIASSUNTOIn questo studio sono stati decritti alcuni aspetti della biologia riproduttiva di Potamon fluviatile, attraverso analisi prevalentemente morfologiche ed istologiche sulle gonadi di entrambi i sessi. L'ovario è costituito da una coppia di organi a forma di sacco, con un epitelio sottile che crea delle invaginazioni a forma di tasca con la funzione di accogliere sia oociti in fase di maturazione che uova mature, mentre gli oogoni sono organizzati all'interno del lume ovarico in gruppi ben definiti (germaria). Le uova, una volta rilasciate dalle tasche ovariche, passano nel lume e da qui, attraverso gli ovidutti, vengono depositate nella camera addominale e fecondate con gli spermatozoi conservati nella spermateca. Il sistema riproduttivo maschile, invece, consiste in una coppia di testicoli, uniti da un sottile tessuto connettivo, e da due dotti deferenti, la cui porzione prossimale mostra un'attività secretoria e dove i gameti, dopo aver lasciato i tubuli testicolari, vengono conservati fino alla loro emissione.

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