The strontium content of roe collected from spawning brown troutSalmo truttaL. reflects recent otolith microchemistry

Abstract

The relationship between the strontium content of the outer layers of otoliths (an indication of recent marine, estuarine or riverine habitat use) and the strontium content of roe in ripe female brown trout Salmo trutta was examined in fish collected from the Pomahaka River and the lower reaches of the Clutha River, South Island, New Zealand. A close relationship was found between the strontium content of roe and the outer layers of otoliths. This finding suggests that spawned eggs collected from redds could potentially be used to track the extent of upstream spawning migrations by anadromous brown trout.

Determining the spatial distribution of spawning by anadromous and resident brown trout Salmo trutta L using strontium content of eggs collected from redds

“…The study builds on previous work by Kalish (1990) who identified differing Sr levels in anadromous and freshwater rainbow trout, Waite et al (2008) who confirmed that Sr levels in eggs reflect the recent maternal habitat use and Gabrielsson et al This is the first study to utilise this approach to precisely map the upstream extent of spawning by anadromous fish.…”

“…High concentrations of Sr in eggs indicate that the female fish have been living in a Sr-rich environment during the period of egg formation (Kalish 1990;Waite et al 2008). The proportion of egg samples with relatively high-Sr concentrations (>150 nmole SrAEg )1 dry weight egg) was high in the two tributaries located below the Taieri River Gorge, but consistently <150 nmole SrAEg )1 egg in the tributaries located above the gorge.…”

“…The range of Sr concentrations observed in eggs in this study (approximately 50-290 nmole SrAEg )1 dry weight egg) was greater than Waite et al (2008;approximately 30-110 nmole SrAEg )1 dry weight egg), suggesting Waite et al (2008) most likely sampled a population of estuarine and freshwater-resident fish in the much larger Clutha River. The range of Sr concentrations observed in eggs in this study (approximately 50-290 nmole SrAEg )1 dry weight egg) was greater than Waite et al (2008;approximately 30-110 nmole SrAEg )1 dry weight egg), suggesting Waite et al (2008) most likely sampled a population of estuarine and freshwater-resident fish in the much larger Clutha River.…”

“…The higher levels of Sr in tissues from anadromous fish can, however, be influenced by the amount of time these fish spend in freshwater prior spawning (Donohoe et al 2008). Waite et al (2008) recently demonstrated that the Sr content of brown trout eggs closely reflects recent maternal habitat use (marine, estuarine or riverine). Waite et al (2008) recently demonstrated that the Sr content of brown trout eggs closely reflects recent maternal habitat use (marine, estuarine or riverine).…”

Methyl mercury in brown trout (Salmo trutta) in Arahura River, New Zealand

“…a transect ran in a cross-section from one otolith edge (starting at 0.30 or 0.48 mm, depending on the otolith) through the primordia (otolith centre) and to the opposite edge (c. 3.0 mm). Sr and Ca levels were measured across the otolith sections with Photon induced Xray Emission analysis using a proton microprobe on a 3 megavolt Van de Graaf accelerator (Waite et al 2008). Simple linear regressions were applied to ascertain the significance of the regression correlation coefficients between MeHg and δ 13 C and δ 15 N in trout muscle tissues .…”