Abstract
The present study aimed in vivo tracking of maturation of male eel by computed tomography (CT). Additionally, individually monitored testes sizes were correlated with the conventionally used external maturity indicators (i.e. eye and nose indexes) in order to test and improve their usefulness at individual level. Testes could be clearly identified with the CT from the end of the third week of hCG administration routinely used to induce maturation in fish. The volume of testes increased exponentially during hormone treatment, and by the end of the sixth week of maturation procedure all males produced motilable spermatozoa. Present results prove that testes size can noninvasively be monitored with CT from maturity level where testes size rich 3000 mm3 volume. Eye and nose indexes are in close correlation with testes volume and thus can also be effectively used to monitor maturaty level of male eel, but preferably only at stock level. However, due to their high individual variability, these indexes can be applied only with caution at individual level and should be supplemented with other noninvasive techniques such as CT.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Berinkey, L. (1966) Halak — Pisces. Fauna Hungarie Vol. XX., No. 2. Akadémiai Kiadó, Budapest.
Bieniarz, K., Epler, P. (1977) Investigations on inducing sexual maturity in the male eel Anguilla anguilla L. J. Fish. Biol. 10, 555–559.
Boëtius, I., Boëtius, J. (1967) Studies in the European eel, Anguilla anguilla (L.). Experimental induction of the male sexual cycle, its relation to temperature and other factors. Medd. Dan. Fisk. Havunders 4, 339–405.
Boëtius, I., Boëtius, J. (1980) Experimental maturation of female silver eels, Anguilla anguilla. Estimates of fecundity and energy reserves for migration and spawning. Dana 1, 1–28.
Boëtius, I., Boëtius, J., Hansen, H. J. M. (1991) Studies on lipid synthesis by incorporation of 14C-acetate during experimental maturation of silver eels, Anguilla anguilla. Dana 9, 1–14.
Dekker, W., van Os, B., van Willigen, J. A. (1998) Minimal and maximal size of eel. Bull. Fr. Peche Piscic. 349, 195–197.
Disler, D. G., Marr, D. S., Rosenthal, D. I. (1994) Accuracy of volume measurements of computed tomography and magnetic resonance imaging phantoms by three-dimensional reconstruction and preliminary clinical application. Invest. Radiol. 29, 739–745.
Dollerup, J., Graver, C. M. (1985) Repeated induction of testicular maturation and spermiation, alternating with periods of feeding and growth in silver eels, Anguilla anguilla (L.). Dana 4, 19–39.
Durif, C., Dufour, S., Elie, P. (2005) The silvering process of Anguilla anguilla: a new classification from the yellow resident to the silver migrating stage. J. Fish Biol. 66, 1025–1043.
Durif, C., van Ginneken, V., Dufour, S., Müller, T., Elie, P. (2009) Seasonal evolution and individual differences in silvering eels from different locations. In: van den Thillart, G., Dufour, S., Rankin, C. (eds) Spawning migration of the European eel. Chapman & Hall Fish and Fisheries Series, Vol. 30. Springer Science + Business Media B. V., New York, pp. 13–38.
Einen, O., Waagan, B., Thomassen, M. S. (1998) Starvation prior to slaughter in Atlantic salmon Salmo salar I. Effects on weight loss, body shape, slaughter- and fillet-yield, proximate and fatty acid composition. Aquaculture 166, 85–104.
Gjerde, B. (1987) Predicting carcass composition of rainbow trout by computerised tomography. J. Anim. Breed. Gene 104, 121–136.
Larsen, L. O., Dufour, S. (1993) Growth, reproduction and death in lampreys and eels. In: Ranklin, J. C., Jensen, F. (eds) Fish ecophysiology. Chapman and Hall, Glasgow, New York, Tokyo, Melbourne, Madras, pp. 74–104.
Müller, T., Molnár, T., Szabó, A., Romvári, R., Hancz, C., Bercsényi, M., Horn, P. (2004) Tracking of the hormonally induced maturation of female eels by computed tomography. Acta Vet. Hung. 52, 235–243.
Müller, T., Romvári, R., Bercsényi, M., Hancz, C., Molnár, T., Szabó, A., Horn, P. (2004) Following the artificially induced eel maturation process by means of in vivo CT scanning. J. World Aquacult. Soc. 35, 217–224.
Palstra, A., Van den Thillart, G. (2009) Artificial maturation and reproduction of the European eel. In: Van den Thillart, G., Dufour, S., Rankin, C. (eds) Spawning migration of the European eel. Chapman & Hall Fish and Fisheries Series, Vol. 30. Springer Science + Business Media B. V., New York, pp. 309–331.
Pankhurst, N. W. (1982) Changes in the skin-scale complex with sexual maturation in the European eel, Anguilla anguilla (L.). J. Fish Biol. 21, 549–561.
Pankhurst, N. W. (1982) Relation of visual changes to the onset of sexual maturation in the European eel, Anguilla anguilla (L.). J. Fish Biol. 21, 127–140.
Pankhurst, N. W., Lythgoe, J. N. (1980) Changes in vision and olfaction during sexual-maturation in the European eel Anguilla Anguilla. J. Fish Biol. 23, 229–240.
Pees, M., Pees, K., Kiefer, I. (2010) The use of computed tomography for assessment of the swim bladder in koi carp (Cyprinus carpio). Vet. Rad. Ultras. 51, 294–298.
Peñaranda, D. S., Pérez, L., Gallego, V., M. Jover, Tveiten, H., Baloche, S., Dufour, S., Asturiano, J. F. (2010). Molecular and physiological study of the artificial maturation process in European eel males: From brain to testis. Gen. Comp. Endocrinol. 166, 160–171.
Perez, L., Asturiano, J. F., Tomás, A., Zegrari, S., Barrera, R., Espinos, F. J., Navarro, J. C., Jover, M. (2000) Induction of maturation and spermiation in the male European eel: assessment of sperm quality throughout treatment. J. Fish Biol. 57, 1448–1504.
Prionas, N. D., Ray, S., Boone, J. M. (2010) Volume assessment accuracy in computed tomography: a phantom study. J. Appl. Clin. Med. Phys. 11, 168–180.
Romvári, R., Hancz, Cs., Petrási, Zs., Molnár, T., Horn, P. (2002) Non-invasive measurement of fillet composition of four freshwater fish species by computer tomography. Aquacult. Inter. 10, 231–240.
Rye, M. (1991) Prediction of carcass composition in Atlantic salmon by computerized tomography. Aquaculture 99, 35–48.
Székely, Cs., Molnár, K., Müller, T., Szabó, A., Romvári, R., Hancz, Cs., Bercsényi, M. (2004) Comparative study of X-ray computed tomography and conventional X-ray methods in the diagnosis of swimbladder infection of eel caused by Anguillicola crassus. Dis. Aqua. Organ. 58, 157–164.
Tesch, F. W. (1983) Der Aal. Verlag Paul Parey. 2 Auflage, Hamburg.
Tesch, F. W. (1991) Anguillidae. In: Hoestlandt, H. (ed.) The Freshwater Fishes of Europe Vol. 2. Clupeidae, Anguillidae. AULA-Verlag, Wiesbaden, pp. 388–437.
van Ginneken, V., Durif, C., Balm, S. P., Boot, R., Verstegen, M. W. A., Antonissen, E., van den Thillart, G. (2007) Silvering of European eel Anguilla anguilla L.: seasonal changes of morphological and metabolic parameters. Anim. Biol. 57, 63–77.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
About this article
Cite this article
Müller, T., Molnár, T., Szabó, A. et al. In Vivo Tracking of Maturation in Male European Eel, Anguilla Anguilla (L.), by Computed Tomography. BIOLOGIA FUTURA 63, 180–188 (2012). https://doi.org/10.1556/ABiol.63.2012.2.2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1556/ABiol.63.2012.2.2