X 



X, 



X " 



120 140 160 



FISH SIZE (kg) 



200 



Figure 4. — Fecundity estimates for swordfish from Hawai- 

 ian waters. 



should be pointed out, however, that while nonran- 

 dom distribution of ova diameters within an ovary 

 may contribute to errors in fecundity estimates, 

 other factors are equally important in making the 

 current methods of measuring fecundity difficult. 

 Other factors include inaccurate estimates of the 

 true ovary weight due to varying amounts of connec- 

 tive tissue left on the ovary surface, and more impor- 

 tant, the varying amount of excess fluids (primarily 

 the preservative) removed from the ovary during the 

 "draining" period. Possibly the most important 

 error factor may be related to the point in maturation 

 when the fecundity estimates are made. In species 

 with multimodal frequency distributions of ova 

 diameters (Yuen, 1955; Otsu and Uchida, 1959), the 

 most advanced modal size group has fewer ova than 

 the modal groups to the left (smaller ova). This sug- 

 gests that resorption of some ova is taking place. 

 Thus, the final number of ova extruded during 

 spawning is less than the number with which the 

 modal group started when the mode first differen- 

 tiated from the primordial ova stock. 



Fecundity estimates of the eight swordfish with 

 early ripe or ripe ova are shown in Figure 4. As 

 indicated in an earlier section, fecundity estimates 

 from three of the fish were based on preserved ovary 

 weights which were estimated from fresh-preserved 

 ovary weight relationship. In Figure 4 two of the 

 eight points appear to be displaced a considerable 

 distance from the general curvilinear relationship of 

 increasing fecundity with increasing fish size. Sam- 

 ple BB-5 with an estimated 914 million ova is consid- 

 erably higher than the general trend, while sample 

 BB-1 with 2.2 million ova is on the lower side. 



From our limited fecundity data, and considering 

 the error factors described above, we estimate the 

 fecundity of swordfish to range from 3.0 million ova 

 for a fish weighing 80 kg to 6.2 million ova for a fish 

 weighing 200 kg. Yabe et al. (1959) estimated the 

 fecundity of a 186 cm (orbit to fork) swordfish to be 

 between 3 and 4 million ripe ova. 



LITERATURE CITED 



CAVALIERE, A. 



1962. Studi sulla biologica e pesca di Xiphias gladius L. 

 Nota I. Boll. Pesca Pise. Idrobiol. 17. 11:123-143. 

 LAMONTE. F. 



1944. Note on breeding grounds of blue marlin and sword- 

 fish off Cuba. Copeia 1944:258. 

 NAKAMURA, H., T. KAMIMURA, Y. YABUTA, A. 

 SUDA, S. UEYANAGI. S. KIKAWA, M. HONMA, M. 

 YUKINAWA. and S. MORIKAWA. 



1951. Notes on the life-history of the sword-fish, Xiphias 

 gladius Linnaeus. [In Engl.] Jap. J. Ichthyol. 1:264-271. 

 MATSUMOTO. W. M., and T. K. KAZAMA. 



1974. Occurrence of young billfishes in the central Pacific 

 Ocean. In R. S. Shomura and F. Williams (editors). Pro- 

 ceedings of the International Billfish Symposium, 

 Kailua-Kona, Hawaii. 9-12 August 1972, Part 2. Review 

 and Contributed Papers. U.S. Dep. Commer., NOAA 

 Tech. Rep. NMFS SSRF-67S, p. 238-251. 

 OTSU, T., and R. N. UCHIDA. 



1959. Sexual maturity and spawning of albacore in the 

 Pacific Ocean. U.S. Fish Wildl. Serv., Fish. Bull. 

 59:287-305. 

 SELLA, M. 



1911. Contribute alia conoscenza della riproduzione e dello 

 sviluppo del pesca-spada (Xiphias gladius L.) Mem. R. 

 Com. Talassografia Italiano 2:1-16. 

 UEYANAGI, S. 



1974. A review of the world commercial fisheries for bill- 

 fishes. In R. S. Shomura and F. Williams (editors). Pro- 

 ceedings of the International Billfish Symposium, 

 Kailua-Kona. Hawaii. 9-12 August 1972, Part 2. Review 

 and Contributed Papers. U.S. Dep. Commer., NOAA 

 Tech. Rep. NMFS SSRF-675. p. l-Il. 

 YABE, H., S. UEYANAGI, S. KIKAWA, and H. 

 WATANABE. 



1959. Study on the life-history of the sword-fish, Xiphias 

 gladius Linnaeus. [In Jap., Engl, summ.) Rep. Nankai 

 Reg. Fish. Res. Lab. 10:107-150. 

 YOSHIDA, H. O. 



1974. Landings of billfishes in the Hawaiian longline 

 fishery. In R. S. Shomura and F. Williams (editors). Pro- 

 ceedings of the International Billfish Symposium, 

 Kailua-Kona, Hawaii, 9-12 August 1972, Part 2. Review 

 and Contributed Papers. U.S. Dep. Commer., NOAA 

 Tech. Rep. NMFS SSRF-675, p. 297-301. 

 YUEN, H. S. H. 



1955. Maturity and fecundity of bigeye tuna in the Pacific. 

 U.S. Wildl. Serv.. Spec. Sci. Rep. Fish. 150, 30 p. 

 YUEN, H. S. H., and F. C. JUNE. 



1957. Yellowfin tuna spawning in the central equatorial 

 Pacific. U.S. Fish. Wildl. Serv., Fish. Bull. 57:251-264. 



147 



