| Publication Type: | Book Chapter |
| Year of Publication: | 2003 |
| Authors: | G. ¡a C. de Le niz, Serdio, A., Consuegra, S., Caballero, P., Alvarez, J. |
| Editor: | M. Lamuela, Alvarez J. |
| Book Title: | Un Viaje de Ida y Vuelta. IV Jornadas del Salm¢n Atl ntico en la Pen¡nsula Ib‚rica |
| Series Title: | IV Jornadas del Salm¢n Atl ntico en la Pen¡nsula Ib‚rica |
| Pagination: | 237-246 |
| Publisher: | Gobierno de Navarra, Dpto. de Medio Ambiente, Ordenaci¢n del Territorio y Vivienda. Gesti¢n Ambiental - Viveros y Repoblaciones de Navarra. |
| City: | Pamplona |
| Keywords: | ACTIVITY, AGE, ATLANTIC SALMON, BODY SIZE, COLOURATION, EGG, EGG SIZE, FECUNDITY, FEMALE, FEMALES, GENETIC, GRILSE, HABITAT, MALE, MALES, OVA, POPULATION, POPULATIONS, REPRODUCTIVE, REPRODUCTIVE STRATEGIES, RIVER, RIVERS, SALMON, SEA AGE, SEX, SEX RATIO, SIZE, SPAIN, SPAWNER, SPAWNING, STRATEGIES, STRATEGY, THEORY, TIMING, TIMING OF SPAWNING |
| Abstract: | We have examined the following aspects of the reproductive biology of Atlantic salmon in Iberian rivers: timing of spawning, body size, sex ratio and female fecundity. Egg size and ova colouration were also examined in some populations. Spawning was found to vary considerably, extending from mid November until early February, though the peak of spawning activity typically took place in December. The sex ratio of spawners was usually biased in favour of males, which had on average a younger sea age and a smaller body size than females. Female fecundity varied considerably between individuals, but was found to be proportionately higher in female grilse than in multi-seawinter females. Egg size was also found to differ between age classes, as well as between populations. Compared to more northerly populations, Iberian Atlantic salmon tend to show a greater relative fecundity and a smaller egg size, as predicted by theory for populations inhabiting extreme, marginal habitats governed by r-demographic processes. Such differences in reproductive strategies have probably a genetic basis and are likely to be adaptive. |
| Reprint Edition: | IN FILE |