460 



Fishery Bulletin 91(3). 1993 



c 



<D 



U 20 - 



<u 



Q_ 



^] Seamount armorhead without mature 

 Microcotyle macropharynx 

 n = 64 



^H [p-pelcg r armorhead 

 n = 51 



18 0.20 0.22 0.24 0.26 0.28 0.30 0.32 0.34 0.36 



Fatness index 

 Figure 2 



Distribution of fatness index for specimens of epipelagic 

 and Southeast Hancock Seamount armorhead Pseudo- 

 pentaceros wheeleri without mature parasites of Microcotyle 

 macropharynx. 



ment surveys (Fig. 3; data taken Somerton and 

 Kikkawa (1992) from FI distributions for each sample 

 period except November 1988). 



Mean HSI ix = 3.147; Fig. 4) of the epipelagic group 

 was significantly different from that of seamount 

 armorhead with FI >0.26 (x = 1.358, Mann-Whitney 

 test, P < 0.001) and those with FI <0.26 (x = 1.028, t- 

 test, P < 0.001). Furthermore, none of the seamount 

 armorhead except for two individuals in the FI >0.26 

 group had HSI values exceeding the lowest value 

 (2.154) of the epipelagic group. Differences between 

 the mean HSI of the two seamount FI groups were 



100 



c 

 u 



CL 



40 



20 



| Stock assessment estimate of percent of SE 

 Hancock armorhead population with Fl>0.26 



^\ Percent of armorhead sample (Fl>0.26) 

 found un-infected with mature stage 

 Microcotyle macro-pharynx 



I 



l^n. fir 



JUN AUG OCT APR AUG JAN JUL AUG NOV 

 1985 19B6 1986 1987 1987 1988 1988 1988 1988 



Sampling period 



Figure 3 



Percent of armorhead Pseudopentaceros wheeleri samples (fat- 

 ness index (FI) >0.26> without mature Microcotyle 

 macropharynx (from Table 3), and the percent of SE Hancock 

 armorhead population with FI >0.26; the latter estimated 

 from stock assessment surveys during each of the periods 

 (except November 1988 1 where armorhead were sampled for 

 M. macropharynx infection. 



(D 



XJ 



c 



o 



V) 



o 



D 

 Q_ 

 CO 



I 



1 -Epipelagic 



2-Seamount. without mature 



Microcotyle macropharynx 

 3-Seamount, Fl>0.26 

 4 — Seamount. with mature 



Microcotyle macropharynx 

 5-Seamount. FK0 26 



:167 



n = 243 



12 3 4 5 



Armorhead groupings 

 Figure 4 



Hepatosomatic index by each grouping of armorhead 

 Pseudopentaceros wheeleri. The mean is indicated by the mid- 

 point horizontal line within each box, one standard deviation 

 about each mean is denoted by the box, and the range is 

 displayed as the horizontal lines above and below the box. 



also highly significant (Mann-Whitney test, P < 0.001). 

 Regardless of FI value, the difference in mean HSI 

 between epipelagics and seamount armorhead without 

 (.r = 1.744, t-test, P < 0.001) and with (x = 1.148, 

 Mest, P < 0.001) mature M. macropharynx remained 

 significantly different, as were differences between the 

 latter two groups (/-test, P < 0.001). The seamount 

 armorhead group without mature M. macropharynx 

 exhibited the least overlap in HSI values with other 

 seamount groups (Fig. 4). 



For the epipelagic group, mean VFSI (x = 2.152; 

 Fig. 5) was significantly different from seamount 

 armorhead with FI >0.26 (x = 3.580, Mest, P < 0.001) 

 and those with FI <0.26 (x = 2.933, Mann-Whitney 

 test, P = 0.007). Mean VFSI differences between the 

 latter two seamount groups were also significant 

 (Mann-Whitney test, P < 0.001). The mean VFSI of 

 the epipelagic group was also significantly different 

 from that of seamount armorhead with (x = 3.185, 

 Mann-Whitney test, P < 0.001) and without (x = 3.663, 

 t-test, P = 0.009) mature M. macropharynx, whereas 

 the latter two seamount groups did not significantly 

 differ in mean VFSI (Mann-Whitney, P = 0.364). Over- 

 lap in VFSI among the various groups (Fig. 5) was 

 substantially greater than exhibited for HSI. 



Discussion 



The complete absence of the monogenean M. 

 macropharynx from all epipelagic armorhead exam- 



