Matching Watershed and Otolith Chemistry to Establish Natal Origin of an Endangered Desert Lake Sucker

Abstract

Like many native endemic desert freshwater fish species, the June Sucker (Chasmistes liorus) is currently listed as endangered. Implicit within the June Sucker recovery plan, is that spawning habitat restoration must result in natural recruitment. I used otolith microchemistry to establish natal origins of the potamodromous June Sucker endemic to Utah Lake, UT, USA, ultimately in order to evaluate whether tributary habitat restoration results in natural recruitment. My specific objectives included; 1) quantify and characterize the extent of chemical variation among the three main spawning tributaries; 2) determine the relationship between otolith microchemistry and tributary chemistry; and 3) develop and validate a classification model to identify stream origin. I quantified the molar ratios Sr:Ca, Ba:Ca, and Mg:Ca for water and otolith chemistry from the three main tributaries to Utah Lake, UT during the summer of 2013. accuracy; random forest model 91% accuracy), and was able to determine if the fish's origin is wild vs. hatchery with 100% accuracy. The use of classification trees and random forest for classification analyses may provide a more powerful method for classification in studies using otolith microchemistry. Overall, this study will aid in evaluating the effectiveness of restoration, track progress toward recovery, help prioritize future restoration plans for the June Sucker in Utah Lake, and can be applied to other imperiled system with species of conservation concern.(59

A Multifaceted Reconstruction of the Population Structure and Life History Expressions of a Remnant Metapopulation of Bonneville Cutthroat Trout: Implications for Maintaining Intermittent Connectivity

“…Consequently, we could not estimate some more complex mark-recapture models as we had originally intended (e.g., by tributary origination, by life stage), as such models are data-hungry and require a long time series. The otolith microchemistry results were extremely useful and interesting, and this approach can offer a powerful tool for reconstructing the life history of a fish, as demonstrated here and elsewhere (e.g., Brenkman et al 2007;Pangle et al 2010;Strohm et al 2017). However, otolith microchemistry will always be limited in applicability for fishes of conservation concern because a fish must be euthanized, though the use of other hard structures (e.g., fin rays) that do not require euthanizing the animal is recently proving promising (e.g., Sellheim et al 2017).…”

“…For the top models (within 2 ΔAICc units) we included the individual covariate total length (TL) to S, R, and R' for the first-year post capture. Survival is often positively related to fish size, and previous work indicates p, R and R' also can vary with fish size (Schaller et al 2014;Budy et al 2017;Clark et al 2018). We only modeled the effect of fish size on the first-year post capture because most fish were not re-measured after initial capture.…”

“…Nonetheless, this genomic research also demonstrated the Weber River metapopulation overall maintains considerable genetic integrity (e.g., lack of introgression). In order to prevent further loss of genetic variation within this BCT population, habitat fragmentation issues need to be corrected (Cegleski et al 2006;Neville et al 2006 697 as a function of size, is a common pattern in fishes (Budy et al 2017;Clark et al 2018; this 698 study). We also observed a strong positive relationship between resight rate and a 2013 699 angler management change requiring catch and release of BCT at the end of the time series.…”

Natal origin and migration pathways of Mekong catfish (Pangasius krempfi) using strontium isotopes and trace element concentrations in environmental water and otoliths

“…The Ba/Ca ratio vs . Sr/Ca ratio in the different tributaries revealed differences that could be used to infer the origin of the water, and, consequently, the movements of fish between them [ 11 , 73 , 74 ]. The differences were particularly marked between the Mekong mainstream and its tributaries [ 11 ].…”

“…The differences were particularly marked between the Mekong mainstream and its tributaries [ 11 ]. While Humston et al [ 73 ] and Strohm et al [ 74 ] showed that there was strong linear relationship between Sr/Ca and Ba/Ca in otoliths and water in various tributaries in the USA, the changes in otolith Sr/Ca and Ba/Ca did not reflect the seasonal river flow [ 37 ]. In the present study, the potential of comparing Sr/Ca and Ba/Ca between water and otoliths to determine the origin of fish origin remains questionable.…”