Spawning period of a southern brown trout population in a highly unpredictable stream

Abstract

– The spawning period of brown trout (Salmo trutta L.) was studied in the river Castril, southern Spain, by means of redd counts. This mountain stream is located near to the southern limit of the species’ natural distribution range and it shows a highly unpredictable flow regime. The spawning period extended from December to mid‐April and the maximum reproductive activity was in February. These results represent the latest reproduction date and the longest spawning period reported in the literature along the natural distribution range of the species. However, belated spawning in the Castril is congruent with the known latitudinal cline: the lower the latitude, the later the spawning period. Our results, along with a review of the literature on natural populations, also showed that the duration of reproduction is the longer, the lower the latitude. Spawning lasted twice as long in the main stem of the river, which is connected with a reservoir, than in the isolated reaches. These differences may be linked to the influence of the reservoir and to habitat fragmentation. We discuss and support the hypothesis that a long spawning period is an advantage for survival in unpredictable habitats. The belated and protracted spawning period found in river Castril has important implications in fisheries management. A strong research effort is needed in order to fill the critical lack of data on southern brown trout populations.

Breeding season, spawning time, and description of spawning behaviour in the Japanese ornate dragonet, Callionymus ornatipinnis: a preliminary field study at the northern limit of its range

“…It is highly likely that this species has relatively longer reproductive periods and two reproductive peaks in temperate waters. A similar phenomenon has been reported by Gortázar et al (2007), who demonstrated a negative correlation between reproductive duration and geographical latitude in brown trout (Salmo trutta). Callionymus ornatipinnis only spawned during a 1-h period at dusk (1730-1830 h), and spawning time was strongly associated with sunset time, but unrelated to the time of high tide.…”

Seasonal and daily upstream movements of brown troutSalmo truttain an Iberian regulated river

“…It has also shown a wide range of variation in its reproductive traits. For instance, many authors have observed significant latitudinal variations in the mean spawning date and in the duration of the spawning period (Klemetsen et al, 2003;Gortázar et al, 2007;Larios-López et al, 2015). Furthermore, during its life cycle, brown trout migrates both long distances for spawning, and shorter ones for feeding or wintering (Klemetsen et al, 2003;Jonsson and Jonsson, 2011).…”

“…Their spawning period in the Iberian Peninsula expands from November to January (Doadrio, 2002), and occasionally until April (Gortázar et al, 2007;Larios-López et al, 2015). However, the dates and environmental triggers of the spawning movements in the Iberian Peninsula for potamodromous populations have not been sufficiently studied.…”

Annual Variation of Spawning Cutthroat Trout in a Small Western USA Stream: A Case Study with Implications for the Conservation of Potamodromous Trout Life History Diversity

“…where n is the number of redds, l is the length of the reach, and s is the number of redd surveys (Baxter et al 1999;Gortazar et al 2007). We incorporated the number of surveys to allow for comparisons between years of different survey effort.…”