Marine and Coastal Fisheries: Dynamics, Management, and Ecosystem Science

摘要: Over the past two decades, declines in populations of river herring (alewife Alosa pseudoharengus and blueback aestivalis) have been documented across both species’ ranges. Information concerning natal origins spawning adult fish could aid their restoration but has unattainable. We investigated efficacy otolith microchemistry for identifying environment alewife Connecticut. In 2008 2009, water juvenile were sampled from 10 sites state. The relationships between Sr:Ca ratios differed alewives herring, necessitating development separate classification models assigning individuals to capture locations. Reclassification age-0 site origin was variable (50–100%) demonstrated that be accurately reclassified at some sites. Discriminant function reclassification rates varied greatly (10–85%); similarity chemical signatures among many likely contributed relatively low assignment majority collection Adult (15–33%) three four sites, probably due overlapping elemental signatures. Blueback collected fourth had a distinct signature rate (81%) comparable highest rate. Changes Ba:Ca sectioned otoliths suggested higher degree movement salinity boundaries during first year life than previously anadromous herring. Otolith may useful tool with which investigate homing history, its utility appears confined particular unique or broader regional assignments origin. Subject editor: Karin Limburg, State University New York, College Environmental Science Forestry, Syracuse, USA *Corresponding author: jason.vokoun@uconn.edu 1Present address: Center Science, Maryland, Post Office Box 38, Solomons, Maryland 20688, USA. Received March 18, 2011; accepted August 23, 2011 358 D ow nl oa de d by [ U ni ve rs ity o f C on ne ct ic ut ] 1 1: 40 5 O ob er 2 01 3 IDENTIFYING NATAL ORIGIN OF ANADROMOUS RIVER HERRING 359 Natal homing, philopatry, is history characteristic shared species fish. Evidence fidelity diverse group fishes, including salmon (Quinn 1993; Quinn et al. 1999), weakfish Cynoscion regalis (Thorrold 2001), bluefin tuna Thunnus thynnus (Rooker 2008), Atlantic cod Gadus morhua (Svedang 2007), Clupea harengus (Brophy 2006), American shad sapidissima (Walther Thorrold 2008; Walther 2008). important ramifications population connectivity, persistence, potential management stocks. Complete nearly complete can isolate breeding as genetic units, requiring managed biological unit. Lower are loosely connected primarily return specific stray, making contributions other Alewives aestivalis alosine along coastline Canada United States northwestern Ocean. similar appearance often collectively referred response recent much fishes’ range (NMFS 2007; Limburg Waldman 2009), multiple states now closed commercial recreational fisheries. moratorium initiated Connecticut 2002, since then Massachusetts, Rhode Island, North Carolina followed suit. 2007 National Oceanic Atmospheric Administration declared concern under Endangered Species Act (NOAA 2007). River jointly single “run” being typical unit focus. This perspective relies untested assumption home rivers high stock mixing negligible. Prior research moderate level, no precise estimates generated. Analyses meristic characters (Messieh 1977), physical tagging adults (Jessop 1994), analysis (Bentzen Paterson 2005) provided evidence philopatry. Additional comes olfactory choice experiments showing preferred streams over alternative choices (Thunberg 1971). Research shown stock–recruitment exist systems 1990), stocking ripe reestablished remnant runs Maine (Havey 1961), suggesting least returning lack straying large part fragility juveniles, makes problematic. studies provide information hindered number need tagged obtain estimates, nonreporting recovered tags (particularly areas fisheries), apparently survival postspawn (Davis Schultz 2009). A more serious issue this method tag recoveries do not represent (the an remains unknown) rather fidelity. Genetic analyses designed clarify structure gene flow well suited estimating several reasons. Some methods, such those analyzing mitochondrial DNA haplotypes (e.g., Palkovacs 2008) variants, yield sufficient differentiation inform among-site movement. Methods focusing parts genome, microsatellites single-nucleotide polymorphisms, would theory accurate estimate regionwide However, work Department Protection (CDEP) U.S. Fish Wildlife Service, wherein spawners trapped transported altered structure. approach used philopatry consistently certain elements incorporated into concentrations reflect composition inhabited (Farrell Campana 1996; 1997; Bath 2000; Milton Chenery 2001; Elsdon Gillanders 2002; Dorval Once otolith, metabolically inert (Campana 2001). contrast based approaches, trap transport activities should minimal effect chemistry. It possible primordia record traces experienced (i.e., marine freshwater) maternal parent (Zimmerman Reeves 2002); however, study any legacy reflected drainages all migrating coastal retrospective examinations diadromous ability technique detect changes individuals, largely through Sr concentration (Limburg 1995; Secor 1998; Rooker Zimmerman 2005; Diouf 2006). microchemical demarcation egress sea essential because it allows freshwater residency site) isolated, enables characterization (Milton 1998a, 1998b; Brazner 2004; Hobbs Tomas Kellison Taylor Whitledge applied herring; capability act natural tracers individual movements valuable compositions. goal using microchemistry.