Alewife ( Alosa pseudoharengus ) spawning and nursery areas in a sentinel estuary: spatial and temporal patterns
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Alewife (Alosa pseudoharengus) spawning and nursery areas in a sentinel estuary: spatial and temporal patterns K. W. Able & T. M. Grothues & M. J. Shaw & S. M. VanMorter & M. C. Sullivan & D. D. Ambrose
Received: 30 January 2020 / Accepted: 27 September 2020 / Published online: 7 October 2020 # Springer Nature B.V. 2020
Abstract Spatial and temporal distribution of anadromous alewife (Alosa pseudoharengus Wilson) spawning and nursery habitats were determined by sampling in the Mullica River – Great Bay watershed (New Jersey, USA) in a combination of long- and short-term observational and quantitative studies. Reproduction was confirmed by examination of developing gonads, visual observations of spawning, and egg collections. Spawning typically lasted 2–4 days in discrete waves in freshwater tributaries from late March to late April. Nursery habitats for larvae and young-of-the-year alewife included low-salinity tributaries near the freshwater-saltwater interface and high salinity waters through early fall before departure to the ocean in late fall. Predation on eggs by fish predators, especially American eel (Anguilla rostrata Lesueur), occurred below a dam. This predation was also observed in the laboratory on eggs and larvae. These findings point out that this dam provided for enhanced predation on alewife early life history stages, and may cause an
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10641-020-01032-0) contains supplementary material, which is available to authorized users. K. W. Able (*) : T. M. Grothues : M. J. Shaw : S. M. VanMorter Rutgers University Marine Field Station, 800 c/o 132 Great Bay Boulevard, Tuckerton, NJ 08087-2004, USA e-mail: [email protected] M. C. Sullivan : D. D. Ambrose Stockton University Marine Field Station, 30 Wilson Avenue, Port Republic, NJ 08241, USA
ecological hotspot for predation-prey interactions for this anadromous species and its catadromous predator. Keywords Alewife . Anadromous . Nursery . American eel . Dam
Introduction The decline in anadromous Alosa spp. (river herrings) along the east coast of the US (Limburg and Waldman 2009; Walters et al. 2009; Hasselman and Limburg 2012; Palkovacs et al. 2013; Twining et al. 2013; Ogburn et al. 2017) and our inability to help them recover points out the lack of understanding we have for the natural history (Able 2016) of these important species. To date, several factors are suspected of contributing to the decline of river herrings including habitat loss, offshore bycatch in pelagic fisheries (Bethoney et al. 2014; Hasselman et al. 2016), overfishing (Turner et al. 2015), or all of these factors combined (Limburg and Waldman 2009). Of certain importance to the decline of river herring is the history of dam creation since European settlement, as this has precluded spawning in many miles of upstream areas (Freeman et al. 2003; Walter and Merritts 2008; Mattocks et al. 2017). In addition, climate change-induced temperature increases may affect the population dynamics
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