Kaufman Les

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Kaufman
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Les
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  • Article
    Sensitivity of sand lance to shifting prey and hydrography indicates forthcoming change to the northeast US shelf forage fish complex
    (Oxford University Press, 2021-01-26) Suca, Justin J. ; Wiley, David N. ; Silva, Tammy L. ; Robuck, Anna R. ; Richardson, David E. ; Glancy, Sarah G. ; Clancey, Emily ; Giandonato, Teresa ; Solow, Andrew R. ; Thompson, Michael A. ; Hong, Peter ; Baumann, Hannes ; Kaufman, Les ; Llopiz, Joel K.
    Northern sand lance (Ammodytes dubius) and Atlantic herring (Clupea harengus) represent the dominant lipid-rich forage fish species throughout the Northeast US shelf and are critical prey for numerous top predators. However, unlike Atlantic herring, there is little research on sand lance or information about drivers of their abundance. We use intra-annual measurements of sand lance diet, growth, and condition to explain annual variability in sand lance abundance on the Northeast US Shelf. Our observations indicate that northern sand lance feed, grow, and accumulate lipids in the late winter through summer, predominantly consuming the copepod Calanus finmarchicus. Sand lance then cease feeding, utilize lipids, and begin gonad development in the fall. We show that the abundance of C. finmarchicus influences sand lance parental condition and recruitment. Atlantic herring can mute this effect through intra-guild predation. Hydrography further impacts sand lance abundance as increases in warm slope water decrease overwinter survival of reproductive adults. The predicted changes to these drivers indicate that sand lance will no longer be able to fill the role of lipid-rich forage during times of low Atlantic herring abundance—changing the Northeast US shelf forage fish complex by the end of the century.
  • Article
    High collocation of sand lance and protected top predators: implications for conservation and management
    (Wiley Open Access, 2020-10-06) Silva, Tammy L. ; Wiley, David N. ; Thompson, Michael A. ; Hong, Peter ; Kaufman, Les ; Suca, Justin J. ; Llopiz, Joel K. ; Baumann, Hannes ; Fay, Gavin
    Spatial relationships between predators and prey provide critical information for understanding and predicting climate‐induced shifts in ecosystem dynamics and mitigating human impacts. We used Stellwagen Bank National Marine Sanctuary as a case study to investigate spatial overlap among sand lance (Ammodytes dubius), a key forage fish species, and two protected predators: humpback whales (Megaptera novaeangliae) and great shearwaters (Ardenna gravis). We conducted 6 years (2013–2018) of standardized surveys and quantified spatial overlap using the global index of collocation. Results showed strong, consistent collocation among species across seasons and years, suggesting that humpback whales and great shearwater distributions are tightly linked to sand lance. We propose that identifying sand lance habitats may indicate areas where humpbacks and shearwaters aggregate and are particularly vulnerable to human activities. Understanding how sand lance influence predator distributions can inform species protection and sanctuary management under present and future scenarios.
  • Article
    The role of sand lances (Ammodytes sp.) in the Northwest Atlantic ecosystem: a synthesis of current knowledge with implications for conservation and management
    (Wiley, 2020-03-20) Staudinger, Michelle D. ; Goyert, Holly ; Suca, Justin J. ; Coleman, Kaycee ; Welch, Linda ; Llopiz, Joel K. ; Wiley, David N. ; Altman, Irit ; Applegate, Andew ; Auster, Peter J. ; Baumann, Hannes ; Beaty, Julia ; Boelke, Deirdre ; Kaufman, Les ; Loring, Pam ; Moxley, Jerry ; Paton, Suzanne ; Powers, Kevin D. ; Richardson, David E. ; Robbins, Jooke ; Runge, Jeffrey A. ; Smith, Brian ; Spiegel, Caleb ; Steinmetz, Halley
    The American sand lance (Ammodytes americanus, Ammodytidae) and the Northern sand lance (A. dubius, Ammodytidae) are small forage fishes that play an important functional role in the Northwest Atlantic Ocean (NWA). The NWA is a highly dynamic ecosystem currently facing increased risks from climate change, fishing and energy development. We need a better understanding of the biology, population dynamics and ecosystem role of Ammodytes to inform relevant management, climate adaptation and conservation efforts. To meet this need, we synthesized available data on the (a) life history, behaviour and distribution; (b) trophic ecology; (c) threats and vulnerabilities; and (d) ecosystem services role of Ammodytes in the NWA. Overall, 72 regional predators including 45 species of fishes, two squids, 16 seabirds and nine marine mammals were found to consume Ammodytes. Priority research needs identified during this effort include basic information on the patterns and drivers in abundance and distribution of Ammodytes, improved assessments of reproductive biology schedules and investigations of regional sensitivity and resilience to climate change, fishing and habitat disturbance. Food web studies are also needed to evaluate trophic linkages and to assess the consequences of inconsistent zooplankton prey and predator fields on energy flow within the NWA ecosystem. Synthesis results represent the first comprehensive assessment of Ammodytes in the NWA and are intended to inform new research and support regional ecosystem‐based management approaches.