Final Report Summary - NECESSITY (Nephrops and CEtacean Species Selection Information and Technology)
The NECESSITY project aimed to develop innovative gear prototypes, acoustic deterrents and fishing tactics, in close collaboration with the fishing industry, so as to minimise by-catches in Nephrops and pelagic fisheries without significantly reducing the catch of target species. In addition, the project aimed to evaluate the biological effects and the social and economic repercussions of the proposed options through the elaboration of a cost and benefit analysis.
The project was organised in ten distinct, yet interconnected, work packages (WPs) which focused on project management, statistical planning and modelling, determination of novel practices and gear modifications, identification of their potential biological impacts, investigation of their social and economic effects and, finally, dissemination and implementation of knowledge. Different working groups investigated young fish and cetacean by-catch in Nephrops and pelagic fisheries respectively.
The principal obstacle in all Nephrops fisheries was that the available technology caught a mixture of species many of which were not targeted. Therefore, devices offering escape opportunities or blocking the passage of unwanted organisms were necessary. In addition, the potential to utilise passive gears rather than trawled gears was tested in the Mediterranean. All proposals were initially tested in a flume tank and the most promising ones were refined and developed in the field, taking into consideration the varying local conditions.
Novel management practices were identified for the Bay of Biscay based on seasonal data of discarded quantities. Furthermore, an existing modelling tool was reviewed to allow for the mechanical simulation of grids and panels, while new software was developed to simulate animals' behaviour in the trawl and around devices. A data recording tool was also designed, as well as a power analysis programme which operated on the Internet and was accessible via the project website.
Similarly, effective and acceptable gear modifications were conceptualised to reduce the by-catch and mortality of cetaceans in pelagic trawl fisheries. The biology and behaviour of dolphins, which were the most common by-catch species, was thoroughly examined at the beginning of the process, so as to propose efficient mitigation measures. The frequency of interactions of cetaceans with trawls though was sporadic and any attempt to develop solutions was greatly impeded. The occurrence of by-catch was analysed in relation to a range of operational variables, however no strong correlation was found. The limited information on fish diurnal, temporal and spatial patterns further increased the task complexity.
A series of excluder devices was tested in the laboratory and selected equipment was further developed in the field. The devices were mainly ropes or panels in the front part and grids in the rear part of the nets. Nevertheless, understanding of the escape mechanisms was insufficiently addressed and additional research was required for equipment optimisation. Moreover, the project focused on the development of acoustic deterrents to reduce cetacean catch without influencing the targeted species. The undertaken efforts had promising results, but the signal characteristics of the two proposed systems were yet to be finalised, based on future field research.
NECESSITY aimed to develop novelties in close collaboration with the end users to ensure their industrial applicability. Therefore numerous communication mechanisms were created, including a website, personal contacts, industry liaison groups, dissemination documents and an interactive digital video disk (DVD).
The project was organised in ten distinct, yet interconnected, work packages (WPs) which focused on project management, statistical planning and modelling, determination of novel practices and gear modifications, identification of their potential biological impacts, investigation of their social and economic effects and, finally, dissemination and implementation of knowledge. Different working groups investigated young fish and cetacean by-catch in Nephrops and pelagic fisheries respectively.
The principal obstacle in all Nephrops fisheries was that the available technology caught a mixture of species many of which were not targeted. Therefore, devices offering escape opportunities or blocking the passage of unwanted organisms were necessary. In addition, the potential to utilise passive gears rather than trawled gears was tested in the Mediterranean. All proposals were initially tested in a flume tank and the most promising ones were refined and developed in the field, taking into consideration the varying local conditions.
Novel management practices were identified for the Bay of Biscay based on seasonal data of discarded quantities. Furthermore, an existing modelling tool was reviewed to allow for the mechanical simulation of grids and panels, while new software was developed to simulate animals' behaviour in the trawl and around devices. A data recording tool was also designed, as well as a power analysis programme which operated on the Internet and was accessible via the project website.
Similarly, effective and acceptable gear modifications were conceptualised to reduce the by-catch and mortality of cetaceans in pelagic trawl fisheries. The biology and behaviour of dolphins, which were the most common by-catch species, was thoroughly examined at the beginning of the process, so as to propose efficient mitigation measures. The frequency of interactions of cetaceans with trawls though was sporadic and any attempt to develop solutions was greatly impeded. The occurrence of by-catch was analysed in relation to a range of operational variables, however no strong correlation was found. The limited information on fish diurnal, temporal and spatial patterns further increased the task complexity.
A series of excluder devices was tested in the laboratory and selected equipment was further developed in the field. The devices were mainly ropes or panels in the front part and grids in the rear part of the nets. Nevertheless, understanding of the escape mechanisms was insufficiently addressed and additional research was required for equipment optimisation. Moreover, the project focused on the development of acoustic deterrents to reduce cetacean catch without influencing the targeted species. The undertaken efforts had promising results, but the signal characteristics of the two proposed systems were yet to be finalised, based on future field research.
NECESSITY aimed to develop novelties in close collaboration with the end users to ensure their industrial applicability. Therefore numerous communication mechanisms were created, including a website, personal contacts, industry liaison groups, dissemination documents and an interactive digital video disk (DVD).
