Spawning areas and migration patterns in the early life history of Squalius cephalus (Linnaeus, 1758): Use of otolith microchemistry for conservation and sustainable management

Abstract

In the context of the River Rhône restoration programme, the objective of this study was to assess the dispersal and population connectivity of the European chub, Squalius cephalus (Linnaeus, 1758) in a section of the natural, free‐flowing part of the lower River Rhône. The elemental water signatures for Sr:Ca and Ba:Ca were measured at seven stations within the river section, including its tributaries and backwaters, to determine whether they could be differentiated by microchemistry. From August to October the signatures differed among three sectors of the study reach: the Rhône; the Ardèche; and the backwaters. The elemental signatures of the otoliths of 178 young‐of‐the‐year (YOY) chub from the stations were measured to assess spawning areas and identify early migratory life histories. Analyses of otolith microchemistry identified the natal origin of 95% of the fish. Sr:Ca signatures of otoliths showed early downstream migration for 30.4% of the YOY chub; however, 70% of the fish recruited relatively close to their spawning origin suggesting a potential inshore retention of fish. The results showed (i) a non‐negligible contribution of the tributaries and backwaters in the recruitment of fish into the main channel; and (ii) the ability of chub to migrate over several kilometres during their first few months of life. This study shows that the combination of water and otolith microchemistry analyses of fish growth increases the understanding of fish life history. Moreover, the study revealed that half of the YOY fish from this river section came from the tributaries and the other half came from reproduction in the River Rhône (despite its high anthropization). These methods offer promising future applications of otolith microchemistry for river management in the context of ecological rehabilitation, especially to assess the effectiveness of measures applied in the restoration of floodplain connectivity for riverine fish population conservation.

A step towards measuring connectivity in the deep sea: elemental fingerprints of mollusk larval shells discriminate hydrothermal vent sites

“…Although used for many years to assess directly larval dispersal in coastal environments (Levin, 1990;Levin et al, 1993;Zacherl et al, 2003;Becker et al, 2005Becker et al, , 2007Carson, 2010;Fodrie et al, 2011;Kroll et al, 2016;Honig et al, 2020;Bounket et al, 2021), elemental fingerprinting of biogenic carbonate structures (such as otoliths or shells) has never been applied to vent species (Mullineaux et al, 2018;Cunha et al, 2020), even though its interest for deep-sea environments has been suggested over 15 years ago (Levin, 2006). This approach relies on the record in calcified structures of the chemical composition of the water in which they have formed (Thorrold et al, 2007).…”

A step towards measuring connectivity in the deep sea: elemental fingerprints of mollusk larval shells discriminate hydrothermal vent sites

“…Genetic methods also use more direct approaches, e.g., based on parentage analyses, but these are applicable only when a very significant fraction of individuals can be sampled (Gagnaire et al, 2015), which in effect happens in only very particular systems, and certainly not in the deep-sea. Surprisingly, although it has been proposed for many years as a tool to study larval dispersal (Levin, 1990;Levin et al, 1993), and has been widely used in coastal environments (Zacherl et al, 2003;Becker et al, 2005Becker et al, , 2007Carson, 2010;Fodrie et al, 2011;Kroll et al, 2016;Honig et al, 2020;Bounket et al, 2021), the alternative approach of elemental fingerprinting of biogenic carbonate structures (such as otoliths or shells) has never been used in deep-sea species (Baco et al, 2016;Cunha et al, 2020). The success of this approach relies on the record in calcified structures of the chemical composition of the water in which they have been built (e.g., Thorrold et al 2007).…”

“…Surprisingly, although it has been proposed for many years as a tool to study larval dispersal (Levin, 1990; Levin et al, 1993), and has been widely used in coastal environments (Zacherl et al, 2003; Becker et al, 2005, 2007; Carson, 2010; Fodrie et al, 2011; Kroll et al, 2016; Honig et al, 2020; Bounket et al, 2021), the alternative approach of elemental fingerprinting of biogenic carbonate structures (such as otoliths or shells) has never been used in deep-sea species (Baco et al, 2016; Cunha et al, 2020). The success of this approach relies on the record in calcified structures of the chemical composition of the water in which they have been built ( e.g.…”

“…Although used for many years to assess directly larval dispersal in coastal environments (Levin, 1990; Levin et al, 1993; Zacherl et al, 2003; Becker et al, 2005, 2007; Carson, 2010; Fodrie et al, 2011; Kroll et al, 2016; Honig et al, 2020; Bounket et al, 2021), elemental fingerprinting of biogenic carbonate structures (such as otoliths or shells) has never been applied to vent species (Mullineaux et al, 2018; Cunha et al, 2020), even though its interest for deep-sea environments has been suggested over 15 years ago (Levin, 2006). This approach relies on the record in calcified structures of the chemical composition of the water in which they have formed (Thorrold et al, 2007).…”

Acanthopagrus latus migration patterns and habitat use in Wanshan Islands, Pearl River Estuary, determined using otolith microchemical analysis

“…Inorganic microelements in otoliths mainly come from water; therefore, the composition of microelements in otoliths of fish in different habitats varies. Strontium and calcium are some of the most commomly trace metals in otolith (Wang et al, 2009;Bounket et al, 2021). According to Farrell and Campana (1996) and Walther and Thorrold (2006), Sr and Ca in otoliths in freshwater and marine fish, respectively, are mainly from water (absorbed through gills).…”