Use of otolith chemical signatures to estimate carp recruitment sources in the mid-Murray River, Australia

Abstract

Recent research has suggested that the Barmah-Millewa forest (BMF) floodplain provides a particularly important spawning ground for carp in the Murray River and that there is a large export of juvenile carp from the BMF into other parts of the Murray River system. This study examined whether chemical analysis of otoliths (fish ear stones) represents a feasible technique for estimating the relative importance of particular sources of carp recruitment in the Murray River. Otolith chemical signatures were analysed for fish collected from three lakes on the BMF floodplain and from three major tributaries of the mid-Murray River. A single site downstream of these potential sources of carp recruitment (Torrumbarry Weir) was then examined to estimate the relative contribution of the BMF and the tributaries to carp recruitment at this site. The results of the study suggest that at least some of the lakes on the BMF floodplain are important sources of carp in the mid-Murray River. Using a maximum likelihood analysis of otolith chemical signatures, it was estimated that Barmah Lake and Moira Lake were the most likely recruitment sources for 98% of the fish collected from Torrumbarry Weir. The study demonstrates the potential application of otolith chemical analyses for determining the relative importance of potential recruitment sources of fish in rivers.

Decoding fingerprints: elemental composition of vertebrae correlates to age-related habitat use in two morphologically similar sharks

“…In otoliths, elements are deposited in concentrations reflecting that of the aquatic environment and can be influenced by the physical properties of that medium (Gillanders & Kingsford 2000, Walther & Thorrold 2006, Brown & Severin 2009). For example, strontium (Sr) typically has high concentrations and is uniform in marine environments, while barium (Ba) shows the opposite pattern and is enriched in freshwater or during flood periods in the low salinity region of freshwater plumes (McCulloch et al 2005, Crook & Gillanders 2006. Concentrations of elements in marine environments reflect proximity to freshwater inputs or nutrient upwellings, with trace element:Ca ratios typically higher in less saline waters (Beamish et al 2005, Kingsford et al 2009).…”

Climate-change threats to native fish in degraded rivers and floodplains of the Murray–Darling Basin, Australia

“…This will have longer-term effects on the habitat use and food resources of native fish. However, fewer floodplain connections may have an impact on common carp recruitment because inundated floodplains provide a significant source of carp recruits in the MDB (Crook and Gillanders 2006).…”

Recruitment sources of invasive Bighead carp (Hypopthalmichthys nobilis) and Silver carp (H. molitrix) inhabiting the Illinois River

“…Only a few published studies have used otolith chemistry to identify natal environment of invasive fishes in large floodplain river systems. Crook et al (2013) and Crook and Gillanders (2006) demonstrated the applicability of otolith microchemistry for identifying recruitment sources of invasive Common Carp (Cyprinus carpio) in two Australian rivers. Shen and Gao (2012) concluded that stable oxygen and carbon isotopic compositions of otoliths could be used to identify natal environment and assess stock structure of Silver Carp in a portion of the middle Yangtze River basin.…”