More Like this

1. Larval transport pathways from three prominent sand lance habitats in the Gulf of Maine

   https://doi.org/10.1111/fog.12580  

   Suca, Justin J. ; Ji, Rubao ; Baumann, Hannes ; Pham, Kent ; Silva, Tammy L. ; Wiley, David N. ; Feng, Zhixuan ; Llopiz, Joel K. ( March 2022 , Fisheries Oceanography)

   Northern sand lance (Ammodytes dubius) are among the most critically important forage fish throughout the Northeast US shelf. Despite their ecological importance, little is known about the larval transport of this species. Here, we use otolith microstructure analysis to estimate hatch and settlement dates of sand lance and then use these measurements to parametrize particle tracking experiments to assess the source–sink dynamics of three prominent sand lance habitats in the Gulf of Maine: Stellwagen Bank, the Great South Channel, and Georges Bank. Our results indicate the pelagic larval duration of northern sand lance lasts about 2 months (range: 50–84 days) and exhibit a broad range of hatch and settlement dates. Forward and backward particle tracking experiments show substantial interannual variability, yet suggest transport generally follows the north to south circulation in the Gulf of Maine region. We find that Stellwagen Bank is a major source of larvae for the Great South Channel, while the Great South Channel primarily serves as a sink for larvae from Stellwagen Bank and Georges Bank. Retention is likely the primary source of larvae on Georges Bank. Retention within both Georges Bank and Stellwagen Bank varies interannually in response to changes in local wind events, while the Great South Channel only exhibited notable retention in a single year. Collectively, these results provide a framework to assess population connectivity among these sand lance habitats, which informs the species' recruitment dynamics and impacts its vulnerability to exploitation.

    

   more » « less
2. Environmental drivers and trends in forage fish occupancy of the Northeast US shelf

   https://doi.org/10.1093/icesjms/fsab214  

   Suca, Justin J ; Deroba, Jonathan J ; Richardson, David E ; Ji, Rubao ; Llopiz, Joel K ( November 2021 , ICES Journal of Marine Science)

   Secor, David (Ed.)

   Abstract The Northeast US shelf ecosystem is undergoing unprecedented changes due to long-term warming trends and shifts in regional hydrography leading to changes in community composition. However, it remains uncertain how shelf occupancy by the region's dominant, offshore small pelagic fishes, also known as forage fishes, has changed throughout the late 20th and early 21st centuries. Here, we use species distribution models to estimate the change in shelf occupancy, mean weighted latitude, and mean weighted depth of six forage fishes on the Northeast US shelf, and whether those trends were linked to coincident hydrographic conditions. Our results suggest that observed shelf occupancy is increasing or unchanging for most species in both spring and fall, linked both to gear shifts and increasing bottom temperature and salinity. Exceptions include decreases to observed shelf occupancy by sand lance and decreases to Atlantic herring's inferred habitat suitability in the fall. Our work shows that changes in shelf occupancy and inferred habitat suitability have varying coherence, indicating complex mechanisms behind observed shelf occupancy for many species. Future work and management can use these results to better isolate the aspects of forage fish life histories that are important for determining their occupancy of the Northeast US shelf. 

   more » « less
3. Two distinct population clusters of northern sand lance ( Ammodytes dubius ) on the northwest Atlantic shelf revealed by whole genome sequencing

   https://doi.org/10.1093/icesjms/fsac217  

   Jones, Lucas F. ; Lou, R. Nicolas ; Murray, Christopher S. ; Robert, Dominique ; Bourne, Christina M. ; Bouchard, Caroline ; Kučka, Marek ; Chan, Y. Frank ; Carlon, David B. ; Wiley, David N. ; et al ( December 2022 , ICES Journal of Marine Science)

   Northern sand lance (Ammodytes dubius) are essential forage fish in most offshore, temperate-to-polar waters on the Northwest Atlantic shelf (NWA), but their population structure and genetic separation from the American sand lance (A. americanus) remain unresolved. We assembled a reference genome for A. dubius (first in the Ammodytidae) and then used low-coverage whole genome sequencing on 262 specimens collected across the species distribution (Mid-Atlantic Bight to Greenland) to quantify genetic differentiation between geographic regions based on single nucleotide polymorphisms. We found strong separation between A. dubius from locations north and south of the Scotian Shelf, largely due to massive genetic differentiation spanning most of chromosomes 21 and 24. Genetic distance increased with geographic distance in the smaller southern cluster but not in the larger northern cluster, where genetic homogeneity appeared across large geographic distances (>103 km). The two genetic clusters coincide with a clear break in winter sea surface temperature, suggesting that differential offspring survival, rather than limited transport, causes a break in realized connectivity. Nuclear and mitochondrial DNA both clearly delineated A. dubius from A. americanus, thereby confirming a species boundary through spatial niche partitioning into inshore (A. americanus) and offshore (A. dubius) sand lance species on the NWA.

    

   more » « less
4. The North Atlantic Ecosystem, from Plankton to Whales

   https://doi.org/10.1146/annurev-marine-010419-010752  

   Pershing, Andrew J. ; Stamieszkin, Karen ( January 2020 , Annual Review of Marine Science)

   Compared with terrestrial ecosystems, marine ecosystems have a higher proportion of heterotrophic biomass. Building from this observation, we define the North Atlantic biome as the region where the large, lipid-rich copepod Calanus finmarchicus is the dominant mesozooplankton species. This species is superbly adapted to take advantage of the intense pulse of productivity associated with the North Atlantic spring bloom. Most of the characteristic North Atlantic species, including cod, herring, and right whales, rely on C. finmarchicus either directly or indirectly. The notion of a biome rests inherently on an assumption of stability, yet conditions in the North Atlantic are anything but stable. Humans have reduced the abundance of many fish and whales (though some recovery is underway). Humans are also introducing physical and chemical trends associated with global climate change. Thus, the future of the North Atlantic depends on the biome's newest species, Homo sapiens. 

   more » « less
5. The role of sand lances ( Ammodytes sp.) in the Northwest Atlantic Ecosystem: A synthesis of current knowledge with implications for conservation and management

   https://doi.org/10.1111/faf.12445  

   Staudinger, Michelle D. ; Goyert, Holly ; Suca, Justin J. ; Coleman, Kaycee ; Welch, Linda ; Llopiz, Joel K. ; Wiley, David ; Altman, Irit ; Applegate, Andew ; Auster, Peter ; et al ( March 2020 , Fish and Fisheries)

   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 ofAmmodytesto 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 ofAmmodytesin the NWA. Overall, 72 regional predators including 45 species of fishes, two squids, 16 seabirds and nine marine mammals were found to consumeAmmodytes. Priority research needs identified during this effort include basic information on the patterns and drivers in abundance and distribution ofAmmodytes, 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 ofAmmodytesin the NWA and are intended to inform new research and support regional ecosystem‐based management approaches.

    

   more » « less