Population structure and reproduction of the deep-water shrimp Plesionika martia (Decapoda: Pandalidae) from the eastern Ionian Sea

The population dynamics, growth, and reproduction of the deep-water pandalid shrimp Plesionika martia were studied in the eastern Mediterranean Sea. Samples were collected monthly (July 1999-June 2000) at a depth range of 440-600 m between Zakynthos Island and Peloponnissos (eastern Ionian Sea, Greece). Additional samples were taken in April and May 2001. Size-frequency distribution revealed that mean female size consistently exceeded that of males throughout the year (CL range: 8-23.5 mm and 9.3-29.1 mm for males and females, respectively). Smaller individuals of both sexes occurred only at depths less than 500 m. Mean size of both sexes increased linearly with depth, whereas a less prominent trend of sex ratio in favor of females by depth was observed. The overall yearly and the monthly sex ratio were in favor of females except during winter, when the two sexes were equally represented. Carapace length-wet weight relationships showed negative allometry, for both males and females. Ovigerous females occurred year around, although the main reproductive season extended from April to October. The smallest ovigerous female was 11.8 mm CL, whereas the size at 50% sexual maturity (CLm50) was estimated as 16.16 mm. Fecundity and reproductive output were found loosely related to shrimp size. The von Bertalanffy growth curve parameters were estimated as: L∞ = 30.6 mm, k = 0.31 year-1 in females and L∞ = 28.2 mm, k = 0.53 year-1 in males. Regarding the major life history traits, P. martia from the eastern Ionian seemed to conform to those in other Mediterranean areas. Nevertheless, some population differences exist, which can be related to the oligotrophic conditions and the lack of fishing pressure in the studied area

Current status and future perspectives of Italian finfish aquaculture

Currently available data show that shellfish and finfish production in Italy, derived both from fisheries and aquaculture activities, is on the order of 474,000 tons, each activity representing 50% of the total amount. In this context, the finfish aquaculture industry contributes on average 31 % to the national aquaculture production and on average 59 % of its value, giving a total amount of 72,000 tons and a value of around 351 million \u20ac (2010). According to FEAP statistics, Italy is the fourth largest finfish producer in EU27, after the UK, Greece, and Spain, while it is also one of the six largest finfish producers among the non-EU and EU member countries, together with Norway, UK, Greece, Turkey, and Spain. Presently, fish culture activities are mainly focused on rainbow trout (Oncorhynchus mykiss, 55.5 %), followed by European sea bass (Dicentrarchus labrax, 13.6 %), gilthead sea bream (Sparus aurata, 12.2 %), gray mullet (Mugil cephalus, 5.3 %), sturgeon (Acipenser spp., 2 %), and European eel (Anguilla anguilla, 1.7 %). Over the last 20 years, freshwater fish production and aquaculture (trout, carp, and eel) have decreased in Italy, with the exception of sturgeon. In contrast, marine fish production has significantly increased during the same period, and the two leading species, European sea bass and gilthead sea bream, presently contribute 25.8 % of the finfish production. From 1,900 tons in 1990, production reached 19,000 tons in 2010, with a 900 % increase, at an average percentage of 4.5 %. In addition, new marine fish species were successfully cultured over the same period. This review outlines the past and present situation of finfish culture in Italy and discusses future developments and priorities, with particular emphasis on new, emerging aquaculture species