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Some aspects of the biology of the garfish Belone belone, were studied based on 453 specimens collected from the central Mediterranean (Tunisia). Total lengths ranged from 24.2 to 55 cm for females and from 25.8 to 52.5 cm for males, respectively. An overall sex ratio of 2.36 ÷ 1 shows significant dominance of females in all size classes and seasons. Age data from otoliths reading revealed that females belonged to age groups from 1 to 4 years and males from 1 to 5 years. Most of the individuals were of age group 2. Length weight relationships and von Bertalanffy growth functions parameters were: W = 0.0003 L 3.419, L∞ = 48.48 cm, k = 0.57 year -1 and to = -1 year for females and W = 0.0002 L 3.530, L∞ = 44.7 cm, k = 0.67 year-1 and to = -1 year for males. Gonadosomatic index pattern indicated that spawning occurs once a year between March and May and extends to June with peak activity in March for both sexes. The length at the first maturity was estimated at a total length of 37.26±0.10 cm for females and 37.17±0.40 cm for males.

The bony fish Lophotus lacepede (Giorna, 1809) and Zu cristatus (Bonelli, 1819) are the two species rarely recorded within the Mediterranean basin, usually reported as accidentally captured in depth (mesopelagic) fishing operations. In the current work, we present the first record of L. lacepede and Z. cristatus in fishing catches from southwestern Tyrrhenian Sea. Moreover, in order to improve existent biological/ ecological knowledge, some bio-related aspects such as feeding aspect, sexual maturity and age estimate have been discussed.

During spring–summer 2013, 23 specimens of the Lessepsian Fistularia commersonii Rüppell, 1838 were studied through occasional catches by artisanal and coastal trawler fisheries in the South of Sicily (Mediterranean Sea). The total lengths (TL, cm, without filament) and weight (W, g) ranged between 69.0 and 104.0 cm and 155 and 798 g, respectively. The estimated sex-combined parameters of the length–weight relationship (k = 9*10–9; b = 3.6) suggested a positive allometry. All pairs of sagittae were examined under a stereomicroscope and the age estimated by counting the complete translucent zones, both as whole and thin sections, with ages from 3 to 5 years. Growth parameters (von Bertalanffy Growth Function: L∞ = 101.4; K = 0.52; A0 = 0) were similar to those reported in the literature using vertebra readings. Some conceptual aspects were taken into account in the potential differences in growth rate between the nowadays-established Mediterranean specimens and the native Indo–Pacific ones.

Publicación online disponible en: http://www.icm.csic.es/scimar/index.php, The otoliths (sagittae and lapilli) and the vertebral centra were evaluated as ageing structures in dolphinfish age 0 juveniles (17.2-72 cm FL) caught in the seasonal small-scale fisheries of Majorca and Sicily (western and central Mediterranean). Different structure preparation techniques were also tested. Mounting and polishing lapilli for preparing frontal sections required significantly less processing time than for the sagittae. The increments in lapillus were clearly visible from the primordium to the otolith margin, whereas the intermediate zone in the sagittae was more opaque and prevented the detection of all the increments. The back-calculated hatchdates for otolith ages showed a good correlation with the species reproduction in the area and provided indirect validation for the age determination. The vertebrae centra showed increments with higher periodicity than seasonal. A test of symmetry on the ages derived from the sagitta and vertebra of the same fish indicated that the vertebra significantly underestimated the age. Considering the structure processing time and increment definition, as well as the age-length relationships obtained, it was concluded that the lapilli were the best ageing structure for juvenile dolphinfish. However, validation experiments should be carried out before the accuracy of this method can be determined., This work is a result of two projects sponsored by the EU DG XIV (Biological Studies Ref. 94/031 and 95/73). Mr. J. Moranta and Ms. E. Batanero (IMEDEA) are thanked for their help in data analysis and manuscript typing respectively. Dr. R. L. Radtke (University of Hawaii) provided useful advice on otolith preparation and interpretation during a sabbatical visit to IMEDEA, granted by the Spanish Education Ministry, and Dr. C. Rodgers revised the English version of the manuscript.

The high variability of growth and longevity estimates for European hake (Merluccius merluccius) reflects the existence of two opposing hypotheses on growth rates that differ by a factor of 2: (1) a fast-growing hypothesis (FGH) with a maximum age near 15 years; and (2) a slow-growing hypothesis (SGH) with a maximum age near 30 years. A recently established regional radiocarbon (14C) reference led to a first-time application of bomb 14C dating in the Mediterranean Sea to three of the largest-sized and potentially oldest-catch female European hake. Because age reading of otoliths is very subjective and poorly defined, these fish were aged blind with bomb radiocarbon (14C) dating as an independent estimate of validated age. The validated ages were compared with the theoretical maximum ages from the most reliable FGH and SGH von Bertalanffy growth functions. Among the three bomb 14C ages, the most diagnostic length-at-age was an alignment with the bomb 14C rise period for two of the three fish, providing validated ages of 22 years (74.5-cm total length) and 25 years (88-cm total length). The results provide estimates of length-at-age that are in agreement with the SGH and cannot be accounted for by the FGH.

The Blackmouth catshark, Galeus melastomus, Rafinesque, 1810 (Carcharhiniformes; Scyliorhinidae), is a common, although at present discarded, by- catch of the bottom trawl fisheries in the Strait of Sicily. Given its ecological interest, data gathered in experimental bottom trawl surveys were analysed in order to describe its distribution and main biological traits. The Blackmouth catshark was sampled almost exclusively on the upper slope (200-800), showing the highest frequency of occurrence (69-100%), biomass (BI; 10-85 kg*km-2) and density (DI; 54-506 N*km-2) indexes in the deeper (501-800m) grounds. Individual size (total length, TL, mm) were between 70-590 and 90-510 in females and males, respectively. The sex ratio (SR) was around 0.5. The SR by size showed a gradual decrease till 450 mm class size, followed by an increase up 1 after 500 mm. Virginal/immature specimens represented the bulk of the samples in both females (77%) and males (65%); the length at 50% of sexual maturity (Lm50%) and corresponding maturity range (Lm25% - Lm75% ) was 433 (423-443) and 380 (366-394) mm, respectively.