Sink rate. The sink rate was measured through a total of 117 TDR deployments (Treatment 1: n = 59; Treatment 2: n = 58)2 from two vessels, the FV Akira V (Treatment 1: n = 44; Treatment 2: n = 45) and the XX Xxxx IX (Treatment 1: n = 15; Treatment 2: n = 13). Baited hooks under Treatment 1 (2.0 m) sank significantly faster in each of the 0-2m, 2-4m and 4-6m depth strata compared to Treatment 2 (5.5 m), for both FV Xxxxx X and XX Xxxx
Sink rate. The sink rate was measured through a total of 34 TDR deployments. Baited hooks sank to a depth of 2 m after 14 seconds, to 4 m after 29 seconds and to 6 m after 50 seconds which is equivalent to a distance aft of the vessel up to 61.2, 126.8 and 218.6 m respectively (Table 11). Table 11: Sink rate data from 34 TDR deployments in the Uruguayan pelagic longline fishery Depth (m) Seconds to depth (Mean) Sink rate (m/s) Distance aft (m) 0 - 2 m 14 0.14 43.2 – 61.2 2 - 4 m 22 0.18 89.5 – 126.8 4 - 10 m 50 0.20 154.3 – 218.6
Sink rate. A total of 85 TDR deployments were conducted over the course of three trips, 39 replicates for Treatment 1(60g SL) and 45 replicates for Treatment 2 (150g SL). The mean sink rate of baited hooks under treatment 1 (60g SLs) was significantly faster under each depth strata (0- 2 m, 2-4 m and 4-6 m) when compared with the sink rate of baited hooks under treatment 2 (150g SLs) (T-Test: p<0.0001) (Table 15, Figure 9). Table 15: Summary of sink rate data collected on South African Domestic Longline Vessels Treatment 1: 60g Treatment 2: 150g Sink rate (m.s- 1) 0-2 m 2-4 m 4-6 m 0-2 m 2-4 m 4-6 m Mean 0.32 0.30 0.30 0.51 0.51 0.46 SD 0.176 0.105 0.134 0.237 0.093 0.159 Max 0.71 0.50 0.50 1.00 0.75 0.69 Min 0.08 0.05 0.02 0.13 0.22 0.06 n 39 39 39 46 46 46 Figure 9: Sink rate profiles (mean ± SD) for Treatment 1 (60g) and Treatment 2 (150g) safe leads
