Pilling et aL: Validation of annual growth increments in the otoliths of Lethnnus mahsena and Aprion virescens 607 



tial examination of P filamentosus otoliths was performed 

 by using scanning electron microscopy, in an attempt to 

 validate the "suspected" annuli through micro-increment 

 counts (Brothers and Mathews, 1987). Unlike the results 

 reported from studies in Hawaii, no consistent pattern of 

 micro-increments was found, although it should be noted 

 that our study was very limited in scope (n=4). Hardman- 

 Mountford et al. ( 1997 ), also using specimens from the Sey- 

 chelles, related assumed "monthly increments" to assumed 

 annuli, finding approximately 12.4 monthly increments 

 within each annual increment. Consistent banding of this 

 tjrpe could not be found during our study for specimens col- 



lected from the same region, even though we had a larger 

 sample size. 



The lack of consistent annual increments in P. filamen- 

 tosus may be due to the biology of the species. Spawning 

 occurs throughout the year, with two peaks (Mees, 1993), 

 and may not provide a sufficient stimulus for zone for- 

 mation. Pristipomoides filamentosus is found at greater 

 depths (between 75 and 150 m) than the other study spe- 

 cies (around 30 m) in conditions that may be buffered 

 against environmental change. Hardman-Mountford et. 

 al. ( 1997 ), however, indicated that the 20-24. 5°C tempera- 

 ture range at this depth (Mees, 1993) is sufficient to leave 



