Specific Contract No.3. Estimation of maximum net length of trammel nets, gilīnets and combined bottom set nets by using the volume or the mass of the net
Name of client: DG MARE
Name of partners: CONISMA, CIBM, CSIS- ICM, CNR-IAMC, COISPA, HCMR, IREPA
Dates (start/end): 10/2011-7/2012
The objective of this project is the estimation of multiplying factors which will allow a quite precise land accurate estimation the overall length (range) of different types of bottomset nets (trammel, Igillnets, combined bottomset nets) and small size driñnets (<2,5km), on the basis of both the weight j and/or the volume of a net amassed or stowed on a fishing vessel's deck, on the dock of a port or placed in basket(s). The study is organised in 3 Working Packages which rationale and objectives are summarised below.
WP1. Review the characteristics of passive nets as reported in literature and identify the technical parameters that mainly affects net structures. Information from various literature sources (peer review and grey literature, reports, etc.), relevant for describing the different types of Mediterranean bottomset nets (trammel, gillnets, combined bottomset nets) and smallsized
driftnets (<2.5 km) will be collected and harmonised into a database which can support quantitative analysis and simulations. In this phase a first attempt to identify the technical features which mainly affect the net volume and weight will be done. To this purpose the involvement of Coast guard and Fishery Inspectors is also foreseen.
WP2. Collect new data on the main technical features of passive nets through surveys and interviews on relevant key national and international initiatives (fishermen, fishing industries, netmakers, etc.) and specialized consultants, in order to implement the information collected during WP1 and to allow the development of WP3 (Passive net length estimation). Additional information on technical data will be collected through direct measurements at on deck harbour.
In this phase an experimental device or meter gauge for a quick gross measurement of the net length will be developed and tested.The new data collected will be harmonised with those from literature and stored in a more detailed and informative database containing new data, parameters, pictures etc. This will allow to test and validate both the qualitative and instrumental models elaborated during WP3.In this phase the local enforcement/control personnel (Coast guard, Fishery Inspectors) will be involved in the collection of new information and mainly in the validation of qualitative and instrumental models.
WP3. Formulate reliable and easy to apply models which enable to establish a relationship between net volume/weight and length. To this purpose standard procedures will be set for the measurement of passive net volume and net weight. In this phase some simple experimental devices for the assessment of the net volume and weight will be developed and tested. The new gauges should be feasible and should be set taking into account the standard inspections procedures. In addition the relationships between net volume and some technical parameters (float dimension, twine thickness, hanging ratio etc.) will be established to identify reliable models (by net type) that enable to derive empirical estimations of the passive net length on the basis of net volume and/or net weight.
LAMANS is responsible for data processing and analysis and expressing by means of a formula the relationship between passive net length and net volumeweight obtained through the data collection.