La reproducción de la cigala (Nephrops norvegicus, Crustacea Decapoda Nephropidae) en diferentes zonas del Mediterráneo

The main aspects of reproduction - namely times of ovarian maturation, brooding and hatching, sizes of maturation and fecundity - were studied in female Norway lobsters in seven areas of the Mediterranean biogeographic subprovince: the Algarve Sea, the Alboran Sea, the Catalan Sea, the Ligurian Sea, the Northern Tyrrhenian Sea, the Adriatic Sea and the Gulf of Euboikos. These included both shelf and slope populations within a latitudinal range of 8°. The reproduction showed clear seasonality with some small differences between areas: maturation delayed by 1-2 months in northern areas (Ligurian, N. Tyrrhenian and Adriatic Seas) compared to southern areas; absence of embryos for periods of 4-5 months in slope females and for less clearly defined periods in shelf females. The case study of the Ligurian Sea was used to illustrate the ovarian cycle and to describe the pre- and post-puberal growth of the female. First mating occurs at an average size of 32 mm CL, which corresponds to age 3+ of the female and the hatching of the first brood corresponds to age 4. Differences were registered in reproductive sizes in the study areas, with a range of 23-30 mm CL for the smallest berried females and a range of 30-36 mm CL in the 50% maturity size. These differences were ascribed to local factors, whereas ages of the basic steps of reproduction were assumed to be unchanged. Females of age 2 formed the most abundant share of the fished stock. An estimate of fecundity was made in terms of brood size (embryos were counted at an early stage of development): the range was 1119-1834 embryos in a standard female of 35 mm CL. Reproductive potential, calculated on the basis of a virtual population analysis, was strongly influenced by the size structure of the female population in each area and there was a ratio of about 14:1 between the least (Ligurian) and the most exploited (Catalan) fishing grounds.En siete áreas de la subprovincia biogeográfica Mediterránea: costas de Algarve, Alborán, mar Catalán, mar Ligur, norte del Tirreno, Adriático y golfo de Euboikos, se estudian los principales aspectos de la reproducción (período de maduración ovárica, incubación y eclosión, talla de primera maduración y fecundidad) de la cigala. Las poblaciones estudiadas proceden tanto de la plataforma como del talud continental abarcando un rango latitudinal de 8º. La reproducción muestra una clara estacionalidad con pequeñas diferencias entre áreas: la maduración puede presentarse retrasada en 1–2 meses en las áreas más septentrionales (Liguria, Tyrrheno y Adriático), respecto a las áreas más meridonales; ausencia de embriones durante 4-5 meses en hembras del talud y períodods menos claramente definidos en las hembras de la plataforma. Se presenta como ejemplo el caso concreto del mar Ligur con el fin de ilustrar el ciclo gonadal y describir el crecimiento pre y post pubertal de las hembras. La primera cópula ocurre alrededor de los 32 mm CL, lo que corresponde a una edad de 3+ años, mientras que la primera eclosión de los huevos corresponderá a los 4 años. También se observaron diferencias en las tallas reproductivas de las hembras entre las distintas zonas, desde un rango de entre 23 y 30 mm CL para las hembras ovadas más pequeñas, hasta un rango de entre 30-36 mm CL, para las hembras en la talla del 50% de madurez. Estas diferencias se atribuyen a factores locales asumiendo que el patrón reproductor básico es el mismo. Las hembras de edad 2 constituyen la mayor parte del stock pescado. La estimación de la fecundidad se establece en base al tamaño de la puesta (embriones contados en los primeros estados de desarrollo). Para hembras estándar de 35 mm de CL, se estimaron un número de huevos entre 1119 y 1834. El potencial reproductor se calculó en base al análisis de la población virtual y fue estrechamente influenciado por la estructura de tallas de la población de hembras en cada área. La máxima diferencia encontrada, con una proporción de 14:1, fue entre Liguria y Cataluña, esta última como zona más explotada

MEDITS-based information on the deep water red shrimps Aristaeomorpha foliacea and Aristeus antennatus (Crustacea: Decapoda: Aristeidae)

Special Volume: Mediterranean marine demersal resources: the Medits international trawl survey (1994-1999)The application of statistical models on a time series of data arising from the MEDITS International Trawl Survey, an experimental demersal resources survey carried out during six years (1994-1999) in the same season of the year (late spring - early summer) using the same fishing gear in a large part of the Mediterranean, has allowed for a study to compare, for the first time, the space-time distribution, abundance, and size structure of the two Aristeids Aristaeomorpha foliacea and Aristeus antennatus throughout most of the Mediterranean Sea. This research has shown a large variability among the six reference areas, that were arbitrarily defined within the basin. In particular the two shrimps do not seem to present any correlation or yield continuity in the years. The same lack of homogeneity was also observed in the time trend of the abundances and frequencies of each of the two species. These data seem to confirm the intrinsic variability of the species, the cause of which is still unknown and undocumented. Nevertheless, a longitudinal gradient of catches has been observed where A. antennatus is more abundant in the west and A. foliacea in the east of the basinVersión del editor1,006

The butterfly squid Stoloteuthis leucoptera in the Mediterranean

The presence of Stoloteuthis leucoptera in the Mediterranean is recorded on the basis of three specimens, including an adult male, caught by IKMT and by commercial otter-trawl in the Ligurian Sea. The hypothesis of a recent immigration is discussed. The list of Mediterranean cephalopods (Mangold Wirz, 1963; Torchio, 1968; Bello, 1986; Mangold & Boletzsky, 1987) includes the Sepiolidae of the subfamily Heteroteuthinae, whose members are supposed to be pelagic throughout their life cycle. Mangold Wirz (1963) recognizes in the Mediterranean fauna the unique species Heteroteuthis dispar, the other authors include H. atlantis Voss, which Voss himself (1955) reported at Messina. To this group may now be added Stoloteuthis leucoptera (Verrill, 1878) a species until now recorded in limited Atlantic areas. Verrill (1881) wrote “This species is an exceedingly beautiful one, when living, owing to the elegance and brilliancy of its colours and the gracefulness of its movements. In swimming it moves its fins in a manner analogous to the motion of the wings of a butterfly.

First record of an egg mass of Loligo forbesi (Cephalopoda: Loliginidae) in the Ligurian Sea, with notes about egg laying patterns in southern populations

Volume: 45Start Page: 27End Page: 3

Large pelagic fish, swordfish, bluefin and small tunas, in the Ligurian Sea: biological characteristics and fishery trends.

This article presents a review and summary of the data on large pelagic fish, collected over the period 1990\u20132007, thanks to national and European Community research programmes. Swordfish are present in the Ligurian Sea at all life history stages. Time series of longline fishing catch per unit effort (CPUE) values showa good exploitation status, possibly related to the dismission of past questionable fishing technics (e.g. \u2018spadare\u2019 nets). CPUE values were also negatively related to North Atlantic oscillation: climatic factors probably had synergic effects. Bluefin is present in the Ligurian Sea with mainly schools of young fish aged 1\u20134 years, which feed on small pelagic fish and on the Ligurian krill Meganyctiphanes norvegica. Recent limitations on catches have severely reduced local fishing activities. Following the dismission of purse seiners, artisanal hook-based fisheries should be maintained, regardless of the length of fish caught, as a way of monitoring stock status. The two most abundant species of small tuna, Sarda sarda and Auxis rochei rochei, are present in the Ligurian Sea at all life stages. In particular, Auxis rochei rochei is a commercially neglected species which, in terms of larval occurrence, is the most abundant in the Mediterranean. Physiomorphological and genetic studies have been recently carried out in order to improve forthcoming exploitation

Growth in length and weight and mercury content in small fattened Bluefin Tuna

In areas where detailed information on wild young bluefin tuna growth is available, the growth performances of fattened specimens of the same age can be estimated. The present study described growth rates and mercury and cadmium content of 3 - 4 years old tuna, caged in the Tyrrhenian Sea

Lista Rossa IUCN dei Pesci ossei marini Italiani

Gli obiettivi principali di questa ricerca sono: 1) la creazione di una rete di esperti per la valutazione del rischio di estinzione delle specie di pesci ossei marini in Italia; 2) la valutazione del rischio di estinzione per tutte le specie di pesci ossei marini; 3) la creazione di una base di riferimento utile in futuro a valutare la tendenza dello stato di conservazione della biodiversità in Italia. La valutazione del rischio di estinzione qui presentata è basata sulle Categorie e Criteri e sulle linee guida più aggiornate della Red List IUCN. Le valutazioni sono state effettuate tramite un workshop tematico con un gruppo di esperti delle diverse specie e aree del territorio nazionale, e revisionate criticamente dalla Società Italiana di Biologia Marina sia nei contenuti sia nell’applicazione del protocollo secondo le linee guida. Tutte le specie di pesci ossei marini, native o possibilmente native in Italia sono state incluse nella valutazione. La valutazione include un'area di interesse più ampia delle acque territoriali italiane. Tuttavia, come spesso accade in mare, le popolazioni della quasi totalità delle specie sono molto ampie e pertanto si estendono ben oltre i confini dell'area di valutazione. Delle 407 specie di pesci ossei marini valutate, 8 risultano a rischio di estinzione nei nostri mari (1.9%). Altre 9 specie sono vicine ad essere considerate a rischio, e per altre 51 specie, che costituiscono il 12.5% di quelle considerate, non esistono informazioni sufficienti a valutare il rischio. Le rimanenti specie (83.3%) non sono a imminente rischio di estinzione. La maggior parte delle popolazioni di pesci ossei marini italiani sono stabili, ma il 7% sono in declino e il 4% in aumento. Le principali minacce per i pesci ossei marini italiani sono rappresentate dall’eccessivo prelievo di pesca, che avviene con attività di pesca mirate a specifiche specie o, più comunemente, sotto forma di bycatch (catture accessorie o accidentali nel corso di pratiche di pesca indirizzate ad altre specie), lo sviluppo urbano costiero e il relativo inquinamento delle acque, le modificazioni dell'habitat indotte dalle attività umane (direttamente o indirettamente, come ad esempio attraverso il cambiamento climatico). Le Liste Rosse sono uno strumento essenziale per identificare priorità di conservazione, ma non sono, di per sé, un elenco di priorità. Altri elementi fondamentali nel definire le priorità includono il costo delle azioni, la probabilità di successo e la percentuale della popolazione globale di ciascuna specie presente in Italia, che determina la responsabilità nazionale nella conservazione a lungo termine delle specie

MEDITS-based information on the deep water red shrimps Aristaeomorpha foliacea and Aristeus antennatus (Crustacea: Decapoda: Aristeidae)

The application of statistical models on a time series of data arising from the MEDITS International Trawl Survey, an experimental demersal resources survey carried out during six years (1994-1999) in the same season of the year (late spring - early summer) using the same fishing gear in a large part of the Mediterranean, has allowed for a study to compare, for the first time, the space-time distribution, abundance, and size structure of the two Aristeids Aristaeomorpha foliacea and Aristeus antennatus throughout most of the Mediterranean Sea. This research has shown a large variability among the six reference areas, that were arbitrarily defined within the basin. In particular the two shrimps do not seem to present any correlation or yield continuity in the years. The same lack of homogeneity was also observed in the time trend of the abundances and frequencies of each of the two species. These data seem to confirm the intrinsic variability of the species, the cause of which is still unknown and undocumented. Nevertheless, a longitudinal gradient of catches has been observed where A. antennatus is more abundant in the west and A. foliacea in the east of the basin.No disponibl

Distribution of the Mediterranean hake populations (Merluccius merluccius smiridus Rafinesque, 1810) (Ostheichthyes: Gadiformes) based on six years monitoring by trawl-surveys: some implications for management

On the basis of trawl survey data collected during the MEDITS project (1994-1999), the distribution of Mediterranean hake populations was described in coastal areas corresponding to about three quarters of both the latitudinal and longitudinal extensions of the Mediterranean Sea, and in the 0-800 m range. Abundance and biomass indices (in terms of number and kg per km2) are presented in 15 geographical sectors and 40 subareas from the Alborán Sea to the Aegean Sea. A statistical analysis by generalized linear modelling performed on such indices per main national blocks (Greece, France, Italy and Spain), and considering the effects of the six years of sampling and the depth, showed that biomass increased from west to east, while for all areas the most significant depth effect appeared between 100 and 200 m, corresponding to the depth range that hosts most of the summer nursery areas. The overall size-frequency distributions in shelf and slope waters, average sizes and total mortality coefficient Z per sector showed that the bulk of the MEDITS samples consisted of young individuals and, with only a few exceptions (western Sardinia, central Aegean), a generalized condition of growth overfishing was apparent. However, no negative trend was found, either in biomass or in average size of fishes, during the six years of the present study. Recruitment patterns were studied by distinguishing the youngest fish as Gaussian groups (modal length from 6 to 9 cm total length) in length-frequency distributions of each subarea and main stratum (shelf and slope). Considering the timing of MEDITS surveys (May-July), this approach emphasised the nurseries in the northern part of the western Mediterranean (Gulf of Lions, Ligurian Sea, northern Tyrrhenian Sea) and in the northern central Mediterranean, where recruitment occurs mainly during spring. On the other hand, few recruits were found in part of the central and particularly in the eastern Mediterranean, where recruitment occurs mainly in summer. MEDITS recruitment patterns therefore gave support to distinctions among Mediterranean hake populations, previously suggested on the basis of vertebral counts and other morpho-physiological, albeit fragmentary, data. In particular the central Mediterranean hake populations do not seem to be homogeneous, with an Adriatic unit very close to the northwestern one. The MEDITS experience therefore suggests that future management measures could take into account both general and regional patterns, the latter concerning mainly the younger fraction of the populations.No disponibl