FISHERY BULLETIN: VOL. 72, NO. 1 



400 



800 



1200 



CATCH (pounds) 

 1600 2000 2400 



1600 



1400 



1200 



:iooo 



800 



; 600 



400 



200 



"1 — r 



1 — \ — r 



2800 3200 3600 



— I — I — 1 — 1 — r- 



4000 



O DIVER 2 

 X DIVER 3 



200 



400 



600 



800 1000 1200 



CATCH (kilogroms) 



1400 



1600 



1800 



3200 



2800 



o 

 < 



2400 



2000 



- 1600 -o 



1200 



800 



- 400 



Figure 4. — Relationship between divers" estimates of bait fish school size and the captain's 

 estimate of the purse seine catch at each structure. A linear regression analysis of the average 

 paired diver estimates yields Y = 76.5 + 0.56A'; /?- = 0.684. A linear regression analysis of 

 the estimates made by each diver yields Y = 11 .b + 0.?04A',- r- = 0.285 for diver one; 

 Y = 55.3 + 0.683A': r^ = 0.704 for diver two; and Y = 98.4 + 0.501A'; r-^ = 0.42 for diver 

 three. 



Recruitment Patterns and Production 



Our observations indicate a rapid reci-uit- 

 ment with fish being observed at structures the 

 day following placement. To obtain estimates of 

 production and recruitment of bait fish to the 

 structures, we made daily diver estimates and 

 purse seine collections at four selected structures. 

 Four other structures, also observed daily by 

 divers, were set on after being in position for 3 

 days. During this period (17-21 August 1970). 

 our structures produced an average of 398 kg 

 (875 lb) per set. These catch rates are not ex- 

 tremely large, but they were made when bait fish 

 were not seasonally available to the local beach 

 seine fishery. No bait was being landed, excei)t 

 for fish captured around our structures. The 

 total daily diver estimates and purse seine col- 

 lections are plotted in Figure 5, along with the 

 3-day accumulative totals, to allow comparison 



of production between the four structures fished 

 daily and the four structures set on once, follow- 

 ing the 3-day soak period. Our day 3 catch results 

 indicate no significant advantage in catch size 

 was realized by allowing the structures to soak 

 for 3 days. The potential total catch, assuming 

 daily sets had been made on the 3-day soak struc- 

 tures, indicated from our consistently conserva- 

 tive diver estimates was three times larger than 

 the actual catch after 3 days' soaking. The total 

 accumulative catch from the four structures set 

 on daily was also approximately three times 

 larger than the actual catch from the four 3-day 

 soak structures even though diver estimates 

 indicated smaller total fish concentrations were 

 present at the .structures set on daily. These 

 results show that a greater total production 

 was obtained by making daily sets. This high 

 rate of daily attraction and the apparent lack 

 offish accumulation provided further indications 



186 



