Effects of recreational fishing on three fish species from the Posidonia oceanica meadows off Minorca (Balearic archipelago, western Mediterranean)

Experimental fishing and visual censuses were conducted at nine Posidonia oceanica sites off Minorca exposed to different levels of fishing intensity to assess the effects of recreational fishing on the species that dominate the catch. Total catch per unit effort (CPUE) was highly seasonal and a statistically significant interaction term existed between the season and the level of fishing intensity. CPUE decreased everywhere at the end of the fishing season (autumn), but such a reduction was more intense at those sites exposed to the highest level of fishing. Visual censuses confirmed that there was a lower abundance of vulnerable fish in autumn. Differences vanished in spring probably because fish reshuffled between the considered sites throughout the winter, when the level of fishing intensity was extremely low. Although the average total lengths of Serranus scriba and Diplodus annularis were unaffected by the level of fishing intensity, the average total length of Coris julis was smaller at the most heavily fished sites. In conclusion, recreational fishing has a relevant impact on most of the exploited species and some of the seasonality reported for the Posidonia oceanica fish assemblages might be caused by the seasonality of the fishery.

How competition controls team production: The case of fishing firms

Under team production, those who monitor individual productivity areusually the only ones compensated with a residual that varies withthe performance of the team. This pattern is efficient, as is shownby the prevalence of conventional firms, except for small teams andwhen specialized monitoring is ineffective. Profit sharing in repeatedteam production induces all team members to take disciplinary actionagainst underperformers through switching and separation decisions,however. Such action provides effective self-enforcemnt when themarkets for team members are competitive, even for large teams usingspecialized monitoring. The traditional share system of fishing firmsshows that for this competition to provide powerful enough incentivesthe costs of switching teams and measuring team productivity must bebellow. Risk allocation may constrain the organizational designdefined by the use of a share system. It does not account for itsexistence, however.

Analysis of warm season thunderstorms using an object-oriented tracking method based on radar and total lightning data

Monitoring thunderstorms activity is an essential part of operational weather surveillance given their potential hazards, including lightning, hail, heavy rainfall, strong winds or even tornadoes. This study has two main objectives: firstly, the description of a methodology, based on radar and total lightning data to characterise thunderstorms in real-time; secondly, the application of this methodology to 66 thunderstorms that affected Catalonia (NE Spain) in the summer of 2006. An object-oriented tracking procedure is employed, where different observation data types generate four different types of objects (radar 1-km CAPPI reflectivity composites, radar reflectivity volumetric data, cloud-to-ground lightning data and intra-cloud lightning data). In the framework proposed, these objects are the building blocks of a higher level object, the thunderstorm. The methodology is demonstrated with a dataset of thunderstorms whose main characteristics, along the complete life cycle of the convective structures (development, maturity and dissipation), are described statistically. The development and dissipation stages present similar durations in most cases examined. On the contrary, the duration of the maturity phase is much more variable and related to the thunderstorm intensity, defined here in terms of lightning flash rate. Most of the activity of IC and CG flashes is registered in the maturity stage. In the development stage little CG flashes are observed (2% to 5%), while for the dissipation phase is possible to observe a few more CG flashes (10% to 15%). Additionally, a selection of thunderstorms is used to examine general life cycle patterns, obtained from the analysis of normalized (with respect to thunderstorm total duration and maximum value of variables considered) thunderstorm parameters. Among other findings, the study indicates that the normalized duration of the three stages of thunderstorm life cycle is similar in most thunderstorms, with the longest duration corresponding to the maturity stage (approximately 80% of the total time).

Preliminary report of the first season work of the International Pluridisciplinary Archaeological Expedition to Bactria 2007

A prior long-term and complex evaluation of the already available data on the geophysical prospecting during the first season work carried out at 2006, at the archaeological site of Tchinguiz Tepe of Termez, took place to decide the strategy to follow during the campaign of 2007. This previous evaluation of the information, on one hand, leaded to the decision to increase the geophysical prospecting at Tchinguiz Tepe, on the other hand, to decide the exact location of areas where the archaeological interventions.would carry out. The main objective at the beginning of this new season was to crosscheck the reliabilityof the measurements and, at the same time, to establish the unknown up to the present archaeologicaland chronological sequence of Tchinguiz Tepe. Meanwhile, the geophysical prospecting also wasextended to the outskirts of the city were the localisation of an unknown up to now Buddhist Monasterywas possible.

Preliminary report of the first season work of the International Pluridisciplinary Archaeological Expedition to Bactria 2006

The International Pluridisciplinary Archaeological Expedition in Bactria (IPAEB) was created in 2006.The name underlines the international character of the team (which includes Uzbeks, Spanish, French, British and Greek members), the presence of specialists from various fields apart from archaeology and the fame of Bactria1.

Preliminary report of the first season work of the International Pluridisciplinary Archaeological Expedition to Bactria 2008

This year the development of our project can be divided into two main clearly different parts, on one hand the laboratory work, where the sampled ceramic individuals has been prepared and analyzed and the elaboration of the data obtained during the excavation of 2007 has been finished and, on the other hand, the field work developed at the archaeological site during this specific year (2008).In the mark of the analytical work a significant number of ceramic individuals (144) from the different stratigraphical units from various areas of the excavation of Termez and Tchinguiz Tepe sampled duringthe new and previous field works has been archaeometrically characterized. This specific material includedindividuals dated into the Hellenistic and Sassanian period, which has been confirmed by C14dating upon organic samples.At the same time, in the mark of the field work of 2008 the archaeological record, already started tobe under study during the excavation of 2007, has been completed and two new archaeological recordshave been registered on of which is located in the area of Tchinguiz Tepe. For the archeological studythe information of the previous geophysical prospecting has been indisputably taken into considerationand the same methodology has been applied to crosscheck the latter archaeological results.

Effects of total fishing prohibition on the rocky fish assemblages of Medes Islands marine reserve (NW Mediterranean)

Visual scuba diving censuses were used to assess the effects of fishing prohibition on abundance and size structure of littoral fish populations by comparing the same benthic communities inside and outside the protected area of Medes Islands (NE Catalonia, Spain). The total number of species found was 43 in the reserve and 44 outside, but the mean value of species richness per sampling station was significantly higher in the protected area. However, diversity, heavily affected by the presence or absence of large schools of pelagic species, showed no significant differences between sites. The prohibition of fishing for 6 years is the first factor affecting the qualitative and quantitative structure of fish populations ('reserve effect'), and depth is the second factor. Thus, except in the cases of Serranus cabrilla and Mullus surmuletus, all other vulnerable species are highly sensitive to the protection measures. The size structure of all vulnerable species was found to be absolutely different at the reserve sites than in the unprotected zones, and the modal size classes of size frequency distributions were always higher in the reserve than outside. The reserve effect was significantly responsible of the differences observed in this change on size structure. Some highly vulnerable species, such as Epinephelus guaza and Sciaena umbra, have only been found in the protected area. Others, such as Sparus aurata, Diplodus cervinus and Dicentrarchus labrax, were much more frequent inside the reserve.

Preliminary report of the first season work of the International Pluridisciplinary Archaeological Expedition to Bactria 2007

A prior long-term and complex evaluation of the already available data on the geophysical prospecting during the first season work carried out at 2006, at the archaeological site of Tchinguiz Tepe of Termez, took place to decide the strategy to follow during the campaign of 2007. This previous evaluation of the information, on one hand, leaded to the decision to increase the geophysical prospecting at Tchinguiz Tepe, on the other hand, to decide the exact location of areas where the archaeological interventions.would carry out. The main objective at the beginning of this new season was to crosscheck the reliabilityof the measurements and, at the same time, to establish the unknown up to the present archaeologicaland chronological sequence of Tchinguiz Tepe. Meanwhile, the geophysical prospecting also wasextended to the outskirts of the city were the localisation of an unknown up to now Buddhist Monasterywas possible.

Preliminary report of the first season work of the International Pluridisciplinary Archaeological Expedition to Bactria 2006

The International Pluridisciplinary Archaeological Expedition in Bactria (IPAEB) was created in 2006.The name underlines the international character of the team (which includes Uzbeks, Spanish, French, British and Greek members), the presence of specialists from various fields apart from archaeology and the fame of Bactria1.

Preliminary report of the first season work of the International Pluridisciplinary Archaeological Expedition to Bactria 2008

This year the development of our project can be divided into two main clearly different parts, on one hand the laboratory work, where the sampled ceramic individuals has been prepared and analyzed and the elaboration of the data obtained during the excavation of 2007 has been finished and, on the other hand, the field work developed at the archaeological site during this specific year (2008).In the mark of the analytical work a significant number of ceramic individuals (144) from the different stratigraphical units from various areas of the excavation of Termez and Tchinguiz Tepe sampled duringthe new and previous field works has been archaeometrically characterized. This specific material includedindividuals dated into the Hellenistic and Sassanian period, which has been confirmed by C14dating upon organic samples.At the same time, in the mark of the field work of 2008 the archaeological record, already started tobe under study during the excavation of 2007, has been completed and two new archaeological recordshave been registered on of which is located in the area of Tchinguiz Tepe. For the archeological studythe information of the previous geophysical prospecting has been indisputably taken into considerationand the same methodology has been applied to crosscheck the latter archaeological results.

Daily activity of sardinian warbler sylvia melanocephala in the breeding season = Actividad diaria de la curruca cabecinegra sylvia melanocephala durante el periodo reproductor

El momento concreto del periodo reproductor puede incidir sobre la actividad diaria y los periodos de reposo de las aves paseriformes. Para investigar este aspecto, hemos analizado los movimientos diarios de 7 machos de curruca cabecinegra Sylvia melanocephala mediante radioseguimiento en un matorral mediterráneo. La actividad tiende en general a decrecer a lo largo del día aunque con algunas variaciones dependiendo del momento concreto del periodo reproductor de cada macho en particular. Se han registrado largos periodos de reposo que no dependen ni del estado reproductor ni del momento del día

Effects of artisanal fisheries on the scorpaenids (Scorpaena spp.) reproduction in the marine protected area of Cap de Creus (NW Mediterranean)

Rockfish species are considered important to the ecology of rocky-reef communities which constitute a key habitat in many coastal marine protected areas (MPAs). These species, which are commercially valuable for artisanal fisheries in the Mediterranean, display particular biological traits that could render them vulnerable to fishing. In this study we monitored the artisanal fisheries of scorpaenids (Scorpaena spp.) in the MPA of Cap de Creus (northwestern Mediterranean) in order to estimate the status of their populations, to link captures with the reproduction of these species, and to evaluate the potential impact that artisanal fishing may have on them. Data from onboard sampling with artisanal fishermen and from fisheries statistics (total landings) were used. Total landings and catch per unit of effort (CPUE) follow a clearly seasonal cycle, with a prominent peak during the summer months coinciding with their spawning season, which may be due to mating behavior prior to fertilization. Although maximum sizes are bigger inside the MPA than in non-protected areas situated close by, a significant percentage of individuals caught inside the MPA are below their size at sexual maturity. Although rockfish seem to be favored by the partial protection of the MPA, the allowed artisanal fisheries are probably impacting the reproduction of these species