674 



Fishery Bulletin 94(4). 1996 



I> 



40- 

 35- 

 30- 

 Z.5 

 2 

 1 5 



- .<=,- 



Figure 4 



The mean number offish caught per hour ( + 1 SE) for four 

 common species in three mesh sizes and in two set 

 durations. 



the mesh. However, several other characteristics 

 unique to O. pullus make this species very vulner- 

 able to capture by gill nets. The fusiform body shape 

 of this species allows even large individuals to enter 

 the mesh of a gill net to about half their body length 

 before further forward movement is prevented. Their 

 sinuous swimming motion and weak pectorals do not 

 allow them to swim backwards out of a gill net or to 

 stop quickly. This, coupled with the tendency of O. 

 pullus to swim below the algal canopy where they 

 are likely to have difficulty detecting the mesh, 

 makes this species one of the most vulnerable to gill 

 nets. 



Aplodactylus arctidens were mostly gilled and 

 tangled when caught in the nets. This mode of cap- 

 ture may be due to the strong dorsal spines in this 

 species' anterior dorsal fin which prevent the mesh 

 from passing further along the fish's body. The dif- 

 ferences between mesh sizes in the proportions of A. 

 arctidens caught by each method may be a result of 

 mesh selectivity. The great number of fish tangled 

 in the 2.5" mesh is probably a result of larger fish be- 

 coming tangled by their fins and spines. Small fish 

 caught initially in equivalent numbers in the larger 

 mesh sizes are able to pass through the net unhindered. 



Set time (hours) 



Figure 5 



The percentage composition of the catch from 

 nets of three mesh sizes in terms of condition of 

 fish after various set times, n = the number of 

 fish landed by each mesh size after each set du- 

 ration. See Table 2 for damage categories. 



Notolabrus fucicola, a labrid species, were mostly 

 gilled when caught in the nets. This is likely to be a 

 result of their labriform swimming motion, which 

 enables them to swim backwards out of the net rather 

 than having to force their way through the mesh. If 

 a labrid's backward motion is not prevented by its 

 gills becoming snagged, it invariably escapes from 

 the mesh. Labrids have also been observed to dis- 

 play a unique rolling motion when first tangled in 



