Based on two fishing trips carried out in the Caribbean Sea in May 1997 and in June 1998, on board of deep sea tuna longline fishing boat, from Chacachacare, Margarita Island, Venezuela, the shape and tension of the longline were determined under working conditions, and the operational depth of hooks were estimated by mechanical simulation method. Lineal scale factor for simulation of a prototype section of six hooks (CL) was 150 and force scale factor (CR) was 370.9. Vessel speed during the operations and sections sagging rate, for trial on test panel, ranged from 4.9 knots (55.3%) to 7.1 (80.5%). The angles of incidence at the ends of the main line of prototype ranged between a mean value of 10.4° (± 0.97 SD) and 29.75° (± 1.59 SD), with a mean value of tension between 2.42 kgf (±. 0.46 SD) and 5.35 (± 1.10 SD). The hooks N°6 and N°6, in a range of vessel speeds, reached depths between 63.9 and 70.4 m, the N°2 and N°5 reached depths between 89.8 and 103.8 m, and the hooks N°3 and N°4 reached depths between 103.2 and 133.1 m. The estimated hook depths showed an inverse relation with the speed at which the main line is set (V L), the sagging rate (k) and the angles of incidence at the end sections of main line (joint between the buoy line and two longline sections). The estimation of horizontal tensions shows a direct relationship with k and VL.
|Translated title of the contribution||Estimation of the operational depth of tuna longline hooks of the Isla Margarita (Venezuela) fishing fleet|
|Number of pages||10|
|State||Published - 2003|