PRISTAS and TRENT: CATCHES OF FISHES IN GILL NETS 



TABLE 4. — Statistical comparisons between catches from 

 low- (S), mid- (M), and deep- (D) water depth zones. 



shal- 



Species 



Depth, mean catch, and 

 significance lines' 



Error 

 df 



Gulf menhaden 



Sea catfish 



Bluefish 



Yellowfin menhaden 



Little tunny 



Atlantic sharpnose shark 



Spanish mackerel 



Atlantic croaker 



Garftopsail catfish 



Hybrid menhaden 



Striped mullet 



Pinfish 



213 



246 



195 



69 



123 

 111 

 198 

 123 

 168 

 36 

 54 

 102 



1 Any two means not underscored by the same line were significantly different 

 at the 5% level. 



menhaden, little tunny, Atlantic sharpnose shark, 

 Spanish mackerel, and gafftopsail catfish were 

 caught in greater numbers as depth increased, and 

 sea catfish were caught in greatest numbers in the 

 deep zone. Conversely, catches decreased with 

 increasing depth for bluefish, Atlantic croaker, 

 striped mullet, and pinfish. 



Net Damage 



Monofilament nets were damaged less than 

 multifilament nets in each depth zone fished. In 

 terms of the amount of surface area damaged, 

 shallow nets received the least and deep nets the 

 greatest (Table 5). When corrected to percent of 

 total webbing damage in nets at each zone, shal- 



TABLE 5. — Average daily net damage in square meters and 

 percent of total net area in relation to depth of net and to webbing 

 material. 



low nets received the greatest proportion of 

 damage. Blue crab, Callinectes sapidus, caused 

 damage to both webbing types. Multifilament 

 webbing was damaged the most, possibly because 

 87% of all blue crabs taken were caught in multi- 

 filament webbing. 



SUMMARY AND DISCUSSION 



In this study, catch per net was higher with 

 monofilament than with multifilament gill nets; 

 over 58% of the 12 most abundant species and over 

 71% of the 4 most abundant food and recreational 

 fishes (bluefish, Spanish mackerel, Atlantic 

 croaker, and striped mullet) were caught in mono- 

 filament nets. 



Catch per net was much greater at night than 

 during the day; about 93% of the 12 most abundant 

 species and about 82% of the 4 most abundant food 

 fishes were taken at night. 



Total catches of the 12 most abundant species 

 were 816 (22%), 1,063 (28%), and 1,859 (50%) fish 

 in the shallow, mid, and deep zones, respectively. 



For evaluation where the amount of webbing 

 could be an important cost factor, total catches in 

 each depth zone were converted to catches per unit 

 surface area of webbing by dividing total catches 

 for the shallow, mid, and deep zones by one, two, 

 and four, respectively. Catches per unit area of 

 webbing for the 12 species combined were 816 

 (45%), 531 (29%), and 465 (26%) fish for the 

 shallow, mid, and deep zones. For the four most 

 abundant species of food fishes unadjusted catches 

 per unit area of net were 407 (56%), 196 (27%), and 

 126 (17%), and adjusted catches per unit area of 

 net were 407 (76%), 98 (18%), and 32 (6%) fish for 

 the shallow, mid, and deep zones. Thus, on either 

 basis, fishing in the shallow zone was the most 

 productive. 



Other factors of importance in this study in 

 terms of overall efficiency included net damage, 

 ease of fishing, cost, and storage of webbing. Daily 

 average net damage was 0.16% for monofilament 

 and 0.24% for multifilament webbing. Fish could 

 be removed faster and fewer crabs were caught in 

 monofilament nets. Monofilament nets tangled 

 less and were set and retrieved faster than multi- 

 filament nets. Disadvantages of monofilament 

 compared to multifilament nets were: greater cost 

 per pound (almost double); more storage room 

 required; and greater difficulty of repairing the 

 webbing owing to the requirement of double knots 

 to prevent slippage. 



107 



