Ulteriori osservazioni sulle prestazioni delle attrezzature a strascico impiegate per la valutazione delle risorse demersali in Italia

Further measurements on characteristics and performances of the fishing gears used for demersal stock assessment in Italy were collected. The parameters measured on the gears were: door spread, net horizontal and vertical openings. Data on characteristics of the vessels and of the fishing gears used were also collected. Functions between the door spread, the horizontal and vertical net opening from one side and the warp length from the other side, were computed with the aim of enabling the estimation of such openings for other hauls made with the same gears tested. The data collected were also compared with those measured in the previous series of tests, as well as with the predictive models which was previously realised with the aim of estimating the harizontal net opening from the knowledge of some parameters easily available without the necessity of specifìc sea tests. Because the old model showed to be inadequate for the gears used by large and smal1 vessels, another model was computed.