Emilio Notti

Old Info for a New Fisheries Policy: Discard Ratios and Lengths at Discarding in EU Mediterranean Bottom Trawl Fisheries

Discarding is considered globally among the most important issues for fisheries management. The recent reform of the Common Fisheries Policy establishes a landing obligation for the species which are subject to catch limits and, in the Mediterranean, for species which are subject to Minimum Conservation Reference Size (MCRS) as defined in Annex III to Regulation (EC) No 1967/2006. Additionally, several other initiatives aim to reduce unwanted catches of target and bycatch species, including species of conservation concern. This raises the need to study discarding patterns of (mainly) these species. In this work we collated a considerable amount of historical published information on discard ratios and lengths at discarding for species caught in EU Mediterranean bottom trawl fisheries. The main aim was to summarize the available historical records and make them more accessible for scientific and managerial needs, as well as to try identifying patterns in discarding. We show discard ratios and lengths at which 50% of the individuals were discarded (L50) for 15 species (nine bony fishes, three crustacean decapods and three elasmobranchs). Discard ratios were usually low for target species such as hake, red mullets and highly commercial shrimps and exemptions from the landing obligation under the de minimis rules could be sought in several cases. Discard ratios were usually higher for commercial bycatch species. Discarding is affected by a combination of factors and for a given species, especially for non-target ones, discards are likely to fluctuate within a fishery, across seasons, years and regions. For most species considered, L50s were lower than the MCRS (when in place) and length at first maturity. L50s of target species, such as hake, were very small due to the existence of market demands for small sized individuals. However, for species of low demand, like horse mackerels, a higher retention size was observed, often exceeding MCRS. Lengths at discarding are affected by legal provisions, market demands but also by biological, population and ecological traits. Understanding the factors that affect discarding constitutes the starting point for designing mitigation measures and management plans to reduce discards and improve the sustainability of the stocks.

Assessment of the Relative Catch Performance of a Surrounding Net without the Purse Line as an Alternative to a Traditional Boat Seine in Small-Scale Fisheries

Abstract The catch performance of a traditional Ligurian boat seine, which is not in line with the European Union regulation, was compared with an experimental surrounding net without the purse line as a potential legal alternative. The relative catch performance between the two gear types was assessed using a new catch comparison method requiring neither paired data collection nor equal number of hauls with the two gears. The comparison was based on the catches of the three species that comprise the bulk of the catch in traditional Ligurian boat seine fisheries: Bogue Boops boops, Saddle Bream Oblada melanura, and Blotched Picarel Spicara maena. The experimental gear exhibited poor catch efficiency for all three species, since it was estimated that the catches would only be 2, 64, and 6%, respectively, of those with the boat seine. For both Bogue and Blotched Picarel these reductions in catch performance were found to be highly significant proving that the experimental surrounding net is not a viable solution to replace the traditional boat seine.

A Bond Graph Approach to Improve the Energy Efficiency of Ships

High fuel consumption coupled with increasing fuel prices, emission regulations and increasing concern about the environment, act as incentives to reduce the energy consumption of ships. However, different barriers hinder the adoption of cost-effective energy saving measures by ship owners and operators. These barriers are the reason for the existence of an ‘energy efficiency gap’ between the current level of energy efficiency and the potential for development of higher order efficiency. Imperfect information regarding the current level of energy consumption of vessels, availability and application of energy saving measures, and the impact of adopting these measures, form a group of so called ‘information barriers’.The main objective of this article is to reduce those information barriers, as faced in shipping and more specifically in the fishing sector. The bond graph methodology is presented as a potential solution to these issues. It is utilized as a modeling and simulation method by which to visualize energy flow in a fishing vessel. The bond graph method is employed to estimate the fuel consumption of the vessel under different operational conditions: steaming, trawling and hauling of the fishing gear. It is also applied in pinpointing the major energy consuming apparatuses onboard the vessel. In this way knowledge regarding the current levels of energy consumption can be increased. The main energy consumers can then be studied to further improve energy efficiency knowledge and subsequently reduce the energy efficiency gap of the fishing vessel. Finally, the effectiveness of implementing a slow steaming strategy as a possible energy saving mechanism is studied.Copyright

Preliminary design of the hybrid propulsion architecture for the research vessel “G. Dallaporta”

This paper presents energy and power evaluations on propulsion and generation systems related to a research vessel, named G. DALLAPORTA. This vessel is used by the National Research Council of Italy for oceanographic campaigns, which are generally carried out in the Mediterranean Sea. The analysis is based on measurements of the main electrical and mechanical parameters, related to on board propulsion, oleodynamic and electric auxiliary systems, with reference to the original thermal configuration of the ship. These preliminary results, obtained through theoretical methodology, make possible the identification of a designing procedure for the hybridization of this vessel, in order to respect the international marine standards, in terms of emissions and safety procedures.

Fuel saving and emission reduction in fisheries: Results of the experimentation of a new magnetic device onboard fishing vessel

This paper reports some tests conducted on a new magnetic device for the reduction of fuel consumption and pollutant emissions, installed onboard an Italian trawler since March 2013 and tested in laboratory in May 2014. The electromagnetic field generated by the device operates as a fuel treatment to the incoming fuel in order to increase the air/fuel mixing process. The consequence of treating fuel with a high magnetic field is supposed to improve combustion of fuel and consequently increasing engine power as well as reducing fuel consumption. The test has been carried out on board a fishing vessel where a fuel consumption measurement system conceived at CNR-ISMAR of Ancona has been installed in 2008 and it is still collecting energy use. The monitoring plan included also emissions measurements in order to evaluate the effects of the magnetic device on the pollutant emissions. Emissions measurements were carried out and results were compared with other trawlers with similar characteristics and same engine. Comparison of fuel consumption between 2012 and 2013 showed a fuel saving of about 4.6%. Also a reduction and modification in emissions has been observed. Nevertheless the small reduction could be influenced by other boundary conditions, thus further analysis are requested. Laboratory tests conducted in May/June 2014 further analyzed the fuel treatment effects of the device. The burning process has been evaluated by means of the Mahler bomb calorimeter.