Paolo Carpentieri

Incidence of lessepsian migrants on landings of the artisanal fishery of south Lebanon

In the last decade, a growing amount of evidence incorporated by several authors as signals of global changes, defined a trend of expansion of thermophilic species in the Mediterranean. This phenomenon is markedly shown by the spread of some non-indigenous fish beyond their natural limits and by their success in the new colonized areas. The incidence of those non-indigenous fish in the catch composition of artisanal fishery of Tyre (South Lebanon) was investigated for the first time using both official data and daily landing site surveys. The explored fleet consisted of 250 small vessels (4–10 m length) with old and not very powerful engines, and about 400–550 fishermen at the end of 2005. Most of the fleet used different types of bottom standing gear, such as trammel nets, set gillnets and bottom longlines, whereas purse seines and other fishing gear (floating longlines, traps) were used less frequently. Landing was composed by a great number of species, many of which were Lessepsian migrants. We recorded a total of 25 Lessepsian species, representing 17 families and composing 37% of the total landing by weight. Some of these non-indigenous species have become important components of local fisheries in the area.

Diel feeding periodicity and daily ration of shelf break fish species

The evaluation of the daily ration and feeding periodicity in a Mediterranean demersal fish assemblage under natural conditions is presented. Data were obtained during four trawl surveys conducted on the shelf-edge of the central Mediterranean Sea. Recently, researchers have begun to consider this area an essential fish habitat due to its extremely high productivity and diversity. The species which typified the assemblage were the fish Macroramphosus scolopax, Lepidotrigla cavillone, Mullus barbatus, Serranus hepatus, Argentina sphyraena and Glossanodon leioglossus. Fish were collected at three hour intervals throughout four 24 h sampling periods representing annual seasons. The study was based on the analysis of catch data and stomach fullness per setting time. Results show significant variation of feeding periodicity among species within daytime. The amount of food consumed daily, calculated according to the Elliott & Persson model, is compared to the patterns reported in literature for Atlantic fish species with similar trophic habits. Higher values of daily consumption could be related to the reproductive period for most of the above mentioned species.

Daily ration and feeding activity of juvenile hake in the central Mediterranean Sea

We investigated daily ration, feeding rhythms and gastric evacuation rates of juvenile (<16 cm total length) European hake Merluccius merluccius, using stomach samples collected during four 24-hour trawl surveys carried out in 2001-2002 on the continental shelf-break (from 120 m to 160 m in depth) off the western coast of central Italy (central Mediterranean Sea). In each survey 8 hauls of 30 minutes were performed every three hours throughout the 24-hour period to cover the entire diel cycle. Diet of juvenile hake was mostly composed of the euphausiid Nyctiphanes couchii, showing a peak in stomach contents during early morning followed by a daytime decrease. Fullness index (%FI) was generally higher during sunrise when migratory activity ceased and juvenile hake return to the bottom after feeding. Concerning the hake abundance the highest density value was obtained in May during the recruitment period. Two independent daily ration estimates were produced. First, an empirical attempt to estimate the daily amount of food consumed was obtained by back-calculating the fresh weight of euphausiid prey ingested by juvenile hake. Estimated values ranged from 4.96-5.89% body wet weight (%BW). Second, the daily ration was computed applying the exponential gastric evacuation models proposed by Elliot & Persson (1978) and Eggers (1979). Daily ration values obtained using these consumption models produced a considerable (15-20%) underestimation of consumption rate for juvenile hake.

The spiny spider crab Maja goltziana (Crustacea: Majidae) in south Lebanese waters

The spiny spider crab Maja goltziana d’Oliveira 1888, is a species of subtropical Atlantic origin (d’Udekem d’Acoz, 1999). It can be found in the eastern Atlantic Ocean from Portugal to the Gulf of Guinea, as well as in the Canary Islands (González Pérez, 1995). Maurin (1968) reported M. goltziana as a common component of the demersal assemblages over detritic–muddy bottoms along the Morocco and Western Sahara coasts. In the Mediterranean Sea it has been occasionally recorded from the Levantine Basin to the Tyrrhenian Sea and it is considered by far the rarest species of the Majidae family (Zariquiey Alvarez, 1968). Due to its rarity, information on its distribution and ecology in the Mediterranean are scarce. Maja goltziana is a eurybathic species, living on a variety of substrata on the continental shelf and upper slope (Soppelsa et al., 2005). Until now, the few specimens found in the Mediterranean were caught at depths between 20 m and 300 m, on soft bottoms with a muddy component of variable quantity (Pallaoro & Dulcic, 2004). So far no more than 20 specimens have been recorded in the Mediterranean. The first specimen was recorded off the Israel coast in the late 1950s (Holthuis & Gottlieb, 1958). From the 1950s the species was recorded in different sectors of the Mediterranean generally with no more than two specimens (Ramadan & Dowidar, 1972; Koukouras, 1979; Kocatas, 1981; Pastore, 1983; Pipitone & Tumbiolo, 1993; Pallaoro & Dulcic, 2004; Vignoli et al., 2004; Soppelsa et al., 2005; Artüz, 2006). We confirmed the presence of M. goltziana in the eastern Mediterranean Sea, documenting the occurrence of a mature ovigerous female and reporting relatively high abundances for this species in the southern Lebanese waters. A total of 52 specimens of M. goltziana (Figure 1) was collected in the south of Lebanon (Tyre) from June 2006 to May 2007, by means of commercial landing (trammel nets and bottom longlines) and experimental fishing surveys. The gear utilized during the fishing surveys was a nylon monofilament gillnet, 2000 m in length and 4 m in height with a stretched mesh size of 26 mm, designed to target the European hake Merluccius merluccius. All specimens have been caught on a sandy–muddy bottom over a wide bathymetric range, between 80 and 275 m depth. For each specimen we measured carapace length (CL; from the median point between the bases of the rostral spines, to the posterior end of the carapace between the intestinal spines) and carapace width (CW; between the bases of third and fourth main lateral spines of both sides) to the nearest 1 mm. The sex was also recorded. Figure 1. Maja goltziana specimens caught in Lebanese waters.

Identification and Characterization of Nursery Areas of Red Mullet Mullus barbatus in the Central Tyrrhenian Sea

AbstractRed Mullet Mullus barbatus is an important target of fishing activities in the central Tyrrhenian Sea, so it is essential to identify its critical habitats in order to manage this resource efficiently. Our research specifically focused on the identification and characterization of nursery areas. The use of spatial interpolation techniques enabled us to identify five nurseries that were highly persistent through time. Moreover, the estimate of juvenile density confirmed the strong aggregation effect of these nursery grounds, as a great portion of young individuals were concentrated in a relatively small surface of the study area. The environmental characterization of these areas showed that juveniles were mainly distributed on bottoms with a relatively high percentage of sand (>70%; P < 0.05). Shannon biodiversity index analysis indicated that the southern nurseries reached the highest values of habitat quality (P < 0.0001). Multivariate analysis showed that nursery grounds were divided into three ...