NOTE Taylor and Murphy Reproductive biology of Xiphias gladius in Straits of Florida 



Results 



Sex and length data were collected from 554 swordfish: 211 

 females 72-281 cm, and 343 males 82-235cm. Gonads were avail- 



able for histological processing from 295 fish 

 (133 males and 162 females), of which 149 

 were ascribed ages. 



Male swordfish mature at a smaller size 

 and younger age than do females. Males 

 begin to mature at ~ 100 cm at age 1 (Tables 

 2, 3). The proportion of mature males in our 

 samples increased rapidly thereafter, and all 

 males were mature by 160 cm or age 5. In 

 contrast, the smallest mature females were 

 ~170cm or age 4, and all females were 

 mature by 220 cm or age 9. The predicted 

 length at 50% maturity, based on the fit of 

 logistic distribution functions to the percent- 

 age mature within size-classes, was signif- 

 icantly less (approximate ^test, Sokal and 

 Rohlf 1981; t' 36.5, df 33, P<0.001) for 

 males (112cm) than for females (182cm). 

 Likewise, age at 50% maturity was signif- 

 icantly younger for males (1.4yr) than for 

 females (5.5yr; t ' 17.7, df 16, P<0.001). The 

 logistic distribution functions for maturity 

 by size-class and age fit observed data well 

 (Tables 2, 3) and are as follows: 



Males: 

 % Mature = i/(i + e(-oo976(LJFL-n2))) 



(n 15, r- 0.980) 



% Mature = i/(i + e(-2-223(AGE-i.40))) 



(n 8, r2 0.990) 



Females: 



% Mature = i/(i + e(-o.«690(LJFL-i82))) 



(n 20, r2 0.966) 

 % Mature = i/(i + e(-i-234(AGE-5.45))) 



{n 10, r2 0.976). 



Swordfish from southeast Florida waters 

 demonstrate group-synchronous oocyte 

 maturation {sensu Wallace and Selman 

 1981). This pattern of oocyte development 

 is characterized by the presence of at least 

 two distinct groups of dissimilar-sized 

 oocytes during the spawning season. Ova- 

 ries from all swordfish in our samples con- 

 tained a dominant group of oocytes <200f.im 

 diameter (Fig. 2). All oocytes within Matur- 

 ing ovaries (Class 3) were <200/^m, although 

 lipid deposition suggests preparation for ac- 

 tive vitellogenesis. Mature ovaries (Class 4) 

 contained an additional distinct group of 

 vitellogenic oocytes at 200-600 ^^m. A third 

 group of oocytes, 600-llOO^im, were pres- 

 ent only in Gravid and Spawning/Partially 

 Spent fish (Classes 5 and 6). This largest 



