NOTE Tserpes and Tsimenides: Determination of age and growth of Xiphias gladius 



599 



tification of known-age fish in the population 

 (Beamish and McFarlane, 1983). 



The present work showed that annuli are formed 

 from late spring to early summer which is the spawn- 

 ing period for swordfish in the Mediterranean (Palco 

 et al., 1981). Since it has been suggested that sword- 

 fish use particular spawning grounds in the Medi- 



terranean (Rey, 1988; Cavallaro et. al., 1991), annu- 

 lus formation may be related to migration of fish to 

 these grounds. A relation between annulus forma- 

 tion and migration has been suggested for the At- 

 lantic swordfish as well (Berkeley and Houde, 1983). 

 Our findings indicate that anal-fin spines are use- 

 ful for ageing swordfish. These are important because 



