Fig 1.
Map of the study area and sub-regions included in both models.
This map shows the bathymetric profile of the coastal region, and NEUS LME ecoregions: The Gulf of Maine (GOM), Georges Bank (GB), Southern New England (SNE), and Middle Atlantic Bight (MAB). The limits of the tan region also represent the US Exclusive Economic Zone (EEZ).
Fig 2.
Flow diagram of the Contemporary Alosine Biomass model.
The color gradient represents the direction of flow; different life stages are represented by small (S), medium (M) and Large (L). Functional groups are ordered by trophic level. Grey bubbles represent all functional groups, the pink bubble in bold letters represents anadromous alosine, and orange bubbles represent fishing fleets.
Table 1.
Functional groups input parameters sources for the Contemporary Alosine Biomass (CAB) model for the NEUS LME.
Inputs parameters are Biomass (B), the production-biomass ratio (P/B) and the consumption-biomass ratio (Q/B), output parameters calculated by EwE are Trophic level (TL), Ecotrophic Efficiency (EE) and the production-consumption ratio (P/Q), signaled in bold. Input data documentation is found in the S1 File.
Table 2.
Functional groups input parameters sources for the Restored Alosine Biomass (RAB) model for the NEUS LME.
Inputs parameters are the production-biomass ratio (P/B), the consumption-biomass ratio (Q/B), and Ecotrophic Efficiency (EE) from CAB model. Output parameters calculated by EwE are Trophic level (TL), Biomass (B) and the consumption-production ratio (P/Q), signaled in bold.
Table 3.
Differences in biomass between the CAB and RAB models.
Fig 3.
Comparing biomass of functional groups benefiting from alosine restoration.
Contemporary and restored biomass for all functional groups impacted by alosine biomass restoration. The y-axis was square transformed to show differences for functional groups with low biomass. Groups that presented biomass change less than to 0.002 mt.km-2 were dropped from the graph. Age groups are represented by size, as small (S), medium (M), and large(L).
Fig 4.
Niche overlap index plot of the forage fish functional groups.
(A) Contemporary Alosine Biomass model. (B) Restored Alosine Biomass model. The color gradient and size of nodes are representing the predator overlap index number. Numbers refer to the functional groups, anadromous alosine are represented by underlined numbers.
Fig 5.
Trophic level decomposition of key species in the Northeast US marine ecosystem.
Roman numerals represent the discrete trophic levels of the functional groups in the Contemporary Alosine Biomass (CAB) and Restored Alosine Biomass (RAB) models. (A) Large Atlantic cod, Gadus morhua. (B) Large summer flounder, Paralichthys dentatus. (C) Pelagic sharks, Sphyrna sp., Carcharodon Carcharias, Prionace glauca, Isurus sp., Lamna nasus, and Alopias vulpinus. (D) Pinnipeds, Phoca vitulina, Halichoerus grypus, Pagophilus groenlandicus, and Cystophora cristata. (E) Odontocetes, Delphinus delphis, Globicephala sp., Grampus griseus, Kogia sp., Lagenorhynchus acutus, Phocena phocena, Physeter macrocephalus, Stenella coeruleoalba, S. frontalis, Tursiops truncatus, Ziphius sp. (F) Seabirds, Calonectris diomedae, Fulmarus glacialis, Larus marinus, L. argentatus, L. philadelphia, Oceanites oceanicus, Phalaropus fulicarius, Puffinus gravis, P. griseus, Rissa tridactyla, Sula bassanus.
Table 4.
The difference in trophic level decomposition (sensu Lindeman) between the CAB and RAB models.
Fig 6.
Keystoneness analysis for both models using KS1 index.
The functional group lists are ranked and ordered in terms of keystoneness, and circle size reflects biomass. (A) Keystoneness and biomass for the CAB, (B) keystoneness and biomass for the RAB model. Forage fish species are highlighted in red, and anadromous alosine group is in bold.
Fig 7.
Contrasting forage fish biomass time series in two Northeast US sub-regions.
(A) In the Middle Atlantic Bight (MAB), the total forage fish biomass trend is driven by similar fluctuations within several different forage fish stocks. (B) In the Gulf of Maine (GOM), the total forage fish biomass trend is mostly driven by Atlantic herring (green line) fluctuations. Biomass data is from NEFSC trawl surveys, 1963 to 2013, with corrected catchability (q).