Abstract
With special reference to tunas and using recent results obtained on the skipjack tuna Katsuwonus pelamis, the authors point out that Gonad Index (GI, defined as the ratio between the weight of the gonads and the size of the fish to the cube) is an inaccurate indicator of each of the different sexual maturity stages commonly used to describe the sexual maturation process of marine fishes. They also show that it would be of interest to determine a GI critical value in order to distinguish females in anadvanced stage of maturation from the others. Using diameter measurements of skipjack tuna oocytes they adjust a non linear model between GI and the diameter of the most advanced group of oocytes. This permits the estimation of a GI critical value. This critical value is discussed.
Similar content being viewed by others
Literature cited
Batts, B. S.: Sexual maturity, fecundity and sex ratios of the skipjack tuna, Katsuwonus pelamis, in North Carolina waters. Chesapeake Sci. 13, 193–200 (1972)
Brock, V. E.: Some aspects of the biology of the aku, Katsuwonus pelamis in the Hawaiian Islands. Pac. Sci. 8 (1), 94–104 (1954)
Bunag, D. M.: Spawning habits of some Philippine tuna based on diameter measurements of the ovarian ova. Philippines J. Fish. 4, 145–177 (1956)
Cayré, P.: Maturité sexuelle, fécondité et sex-ratio du listao Katsuwonus pelamis des côtes d'Afrique de l'Ouest (O°–20°N), étudiées à partir des débarquements thoniers (1977–1979) au port de Dakar (Sénégal). ICCAT Col. Vol. Sci. Pap. XV (1), 135–149 (1981)
Cayré, P. et H. Farrugio: Biologie de la reproduction du listao Katsuwonus pelamis de l'Océan Atlantique. Doc. SKJ. Conf./83/12, présenté à la réunion de clôture du Programme International de Recherches sue le listao Atlantique, Teneriffe (Espagne), juin 1983: 62 pp. (à paraître)
Kaya, C. M., A. E. Dizon, S. D. Hendrix, T. K. Kazama and M. K. K. Queenth: Rapid and spontaneous maturation, ovulation, and spawning of ova by newly captured skipjack tuna, Katsuwonus pelamis. Fish. Bull. U.S. 80, 393–396 (1982)
Kikawa, S.: Observations on the spawning of the big-eyed tuna (Parathunnus mebachi, Kishinouye) near the southern Marshall islands. (In Ipn, résumé angl.) Contrib. Nankai Reg. Fish. Res. Lab. 1 (24), 10 pp. (1953)
Matsumoto, W. M., R. A. Skillman and A. E. Dizon: Synopsis of biological data on skipjack tuna, Katsuwonus pelamis. FAO, Fisheries synopsis no. 136, NOAA Tech. Rep. NMFS Circ. 451, 92 pp. 1984
Raju, G.: Studies on the spawning of the oceanic skipjack, Katsuwonus pelamis L., in Minicoy waters. In: Proceedings of the Symposium on scombroid fishes; Mar. Biol. Assoc. India, Symp. Ser. 1, 744–768 (1964)
Ross, R. I. S.: The efficient use of function minimization in non-linear maximum likelihood estimation. Appl. Stat. 19, 205–221 (1970)
Schaefer, M. B. and C. I. Orange: Studies of the sexual development and spawning of yellowfin tuna Neothunnus macropterus and skipjack Katsuwonus pelamis in three areas of the eastern Pacific ocean, by examination of gonads. Inter-Am. Trop. Tuna Com. Bull. 1 (6), 283–349 (1956)
Sharp, G. D.: Colonization: modes of opportunism in the oceans. In: Rep. and Sup. Doc. of the Workshop on the effects of environmental variations on the survival of larval pelagic fishes; Lima. Pérou (Ed. by G. D. Sharp) 10 C Workshop. Ser. no. 28, 323 pp. Paris: UNESCO/10 1981
Tomassone, R., E. Lesquoy and C. Millier: La régression: regards nouveaux sur une technique ancienne. Ed. by A. S. A. Masson. Paris: INRA 1982
Yoshida, N. O.: Skipjack tuna spawning in the Marquesas islands and Tuamota archi-pelago. U.S. Fish. Wildl. Serv., Fish. Bull. 65 (2), 479–488 (1966)
Yuen, H. S. H.: Maturity and fecundity of bigeye tuna in the Pacific. U.S. Fish. Wildl. Serv. Bull. 57 (112), 251–264 (1955)
Author information
Authors and Affiliations
Additional information
Communicated by O. Kinne, Oldendorf/Luhe
On temporary assignment at the Institut Sénégalais de Recherches Agricoles, Centre de Recherches, Océanographiques de Dakar-Thiaroye; B.P. 2241, Dakar, Sénégal
Rights and permissions
About this article
Cite this article
Cayré, P., Laloë, F. Review of the Gonad Index (GI) and an introduction to the concept of its “critical value”: application to the skipjack tuna Katsuwonus pelamis in the Atlantic Ocean. Mar. Biol. 90, 345–351 (1986). https://doi.org/10.1007/BF00428558
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00428558