Mullet va. Herring 



A limited experiment was conducted on Smith cruise 5 (July 1950) 

 alternating, by baskets, mullet ( MurI 1 vaiglensls (^uoy and Gaimard and M. longimanxis 

 Giinther) and herring for the entire set of 30 basketsS/. Table 10 gives the re- 

 suits of the chi-aquare analysis of tiie yellowfin catch from this experiment. The 

 reversals of the catch with the kind of bait indicate an absence of bait preference, 

 although the total catch shows a higher number of yellowfin caught with mullet. 

 Since data on bait return are not available for this cruise, it la not possible to 

 detennlne whether the Interaction shown in table 10 ( x^ _ 5.95^ P<0.05) was due 

 to differences in retention of the two bait species. 



Table 10. — Chl-square analysis of yellowfin catch by 

 herring and mullet baits, Hugh M. Smith 

 cinalse 5 (based on 90 hooks per bait per 

 fishing station) 



Sardine vs. Squid 



A more extensive experiment alternating, by basket, salted sardine and 

 frozen squid (probably Lpllgo opalescens Berry) for 50 baskets was carried out at 

 25 stations on cruise 15' of the Manning (October-November 1952). The chl-square 

 analyses, testing for differences In catch and bait return, are given in table 11. 

 A study of the total catch by the two kinds of baits shows a significantly higher 

 number of fish caught on the sardine baits (pooled X^ = 4.60, P<0.05). However, 

 the significance of the statistical test only indicates a tendency for more fish 

 to be caught with sardine, since the total chl-square is nonsignificant (P>0.05). 

 Before attributing this difference to bait preference, bait availability must be 

 considered. An analysis of the bait returns showed that more squid remained on 

 the hooks, and the difference gave highly significant total and pooled chl-squares 

 (P<0.01). However, the Interaction chl-square was also significant (P<0.0l), 

 Indlcatlne the presence of a factor or factors not accounted for. The bait returns 

 (table 31) show that squid were retrieved in greater numbers than sardine on all 

 but five stations. A possible reason for the reversals is discussed in a later 

 section. 



Examination of the results by species of catch indicates some variation 

 in the effectiveness of the two baits (table 11). Of a total of 135 yellowfin, 

 77 were caught on sardine and 58 on squid baits. However, the difference of 19 

 yellowfin was not statistically significant (P>0.05); thus no preference can be 

 established. The analysis of bait return at stations with yellowfin catches showed 

 that 1.3 times more squid than sardine remained on the hooks, the total, pooled, 

 and interaction chl-squares being significant (P<0.01). 



5/ The gear used on this early cruise differed in some respects from that used on 

 subsequent criiises. Each basket had five branch lines of varying lengths (two 

 72 feet, two 132 feet, and one 252 feet) attached at equal intervals to a 

 mainline section of 1,440 feet. 



11 



