Figure 1.
Mean flight initiation distance (FID) (cm ± S.E) at each fishing ground for six coral reef fish families.
FID was estimated for individuals of six families of coral reef fishes at four different fishing pressures. From left to right within each family, bars are: Kavulik no-take area (no fishing); Ungakum (low fishing pressure); Nusa (intermediate fishing pressure); and Mongol (high fishing pressure). If significant differences existed in FID within families at different fishing grounds, grounds were grouped by similarity (a, b and c). Dashed line is maximum distance at which rifle-style spear guns used in New Ireland province are considered effective (approximately 310 cm, Feary et al. [12]).
Table 1.
Analysis of covariance (ANCOVA) results of flight initiation distance (cm) with fishing pressure as a fixed factor and fish body size (cm TL) and group size as co-variates.
Figure 2.
Effect of body size (cm TL) on flight initiation distance (cm).
Flight initiation distance plotted against fish body size for: (a) Acanthuridae; (b) Scaridae; (c) Balistidae; (d) Mullidae; and (e) Serranidae. Black circles, open circles, inverted red triangles and upright green triangles represent Kavulik no-take area (no fishing), Ungakum (low fishing pressure), Nusa (intermediate fishing pressure) and Mongol (high fishing pressure) fishing grounds, respectively. Solid lines are significant linear regression across all grounds and dotted lines are 95% confidence intervals. For significance and R2 values see Table 2. Note that scales differ on both X and Y axes.
Figure 3.
Effects of group size on flight initiation distance of Acanthuridae.
Group size (number of individuals) plotted against FID (cm) for Acanthuridae. Black circles, open circles, red triangles and green triangles represent Kavulik no-take area (no fishing) Ungakum (low fishing pressure), Nusa (intermediate fishing pressure) and Mongol (high fishing pressure) fishing grounds respectively. Solid line is significant linear regression across all grounds and dotted lines are 95% confidence intervals. For significance and R2 values see Table 2.
Table 2.
R2 values of linear regression analysis of flight initiation distance with body size (cm TL) and group size reported by family and fishing ground.
Figure 4.
Pre-flight behavior of six reef fish families across four fishing grounds with different fishing pressures.
Occurrence (%) of pre-flight behavioral categories in: (a) Acanthuridae; (b) Scaridae; (c) Balistidae; (d) Lutjanidae; (e) Mullidae; and (f) Serranidae across four reef areas in Papua New Guinea. Darkest shading indicates no notice behavior, followed by tacking away, orientating towards refuge, watching, and inspecting as shading becomes lighter.