Drivers of euphausiid distribution and abundance in the Northeast U.S. Shelf Large Marine Ecosystem

2018 ◽  
Vol 75 (4) ◽  
pp. 1280-1295 ◽  
Author(s):  
Michael R Lowe ◽  
Gareth L Lawson ◽  
Michael J Fogarty
Keyword(s):  
Spatial Distribution ◽  
Continental Shelf ◽  
Gulf Of Maine ◽  
Marine Ecosystem ◽  
Atlantic Multidecadal Oscillation ◽  
Outer Continental Shelf ◽  
Bottom Waters ◽  
Large Marine Ecosystem ◽  
Zooplankton Communities ◽  
Broad Scale

Abstract Euphausiids, or krill, often dominate the biomass of zooplankton communities in high latitude marine ecosystems and are recognized as a key component of food webs. Compared to other ecosystems, however, there is scant information regarding the broad-scale distribution of euphausiids in the Northeast U.S. Shelf Large Marine Ecosystem (NEUS-LME). Using long-term (1977–2011) zooplankton survey data, we examine the drivers of the broad-scale spatial distribution and inter-annual variability in euphausiid abundance throughout the entire NEUS-LME. Our results show strong seasonal patterns in both the abundance and spatial distribution of euphausiids, which were commonly associated with waters exceeding 100 m, the continental shelf break (SB), and warmer and more saline bottom waters. Inter-annual patterns in euphausiid abundance were positively correlated with the Atlantic Multidecadal Oscillation (AMO) and bottom salinity, and inter-annual variation was most conspicuous at the outer continental shelf and SB. Assemblage analyses indicated that Euphausia krohnii, Thysanoessa gregaria, T. longicaudata, and Nematoscelis megalops dominated in waters associated with the outer shelf and SB, while Meganyctiphanes norvegica was more important in the Gulf of Maine. These results improve our understanding of the distribution and abundance of euphausiids and provide important information for effective ecosystem-based fisheries management for the NEUS-LME.

scholarly journals TEMPERATURE, SALINITY AND OXYGEN CLIMATOLOGY OF AFRICAN CONTINENTAL SHELF WATER, SOUTH OF THE EQUATOR, AND CHANGES SINCE 1945

2021 ◽  
Author(s):  
Stephanie de Villiers
Keyword(s):  
Continental Shelf ◽  
Environmental Variability ◽  
Marine Ecosystem ◽  
Ecosystem Approach ◽  
Shelf Water ◽  
Classification Schemes ◽  
Continental Shelf Water ◽  
Large Marine Ecosystem ◽  
Oceanographic Data ◽  
Spatial Grid

The first temperature, salinity and oxygen climatologies for waters of the continuous southern African continental shelf is presented. It is based on oceanographic data collected since 1945, sub-sampled at depths of 5, 50 and 100 m on a mixed-spatial grid with 0.25° to 0.5° resolution. The climatologies capture spatial heterogeneities and seasonal variability in key ocean variables for the southern African shelf in unique detail. The results correspond relatively well with biogeographic boundaries informed by classification schemes grounded in taxonomy, but questions the value of the Large Marine Ecosystem approach. Analysis of decadal trends demonstrates the inherent complexity and spatial heterogeneity associated with environmental variability, and suggest the possibility that decadal periodicities are in the process of being disrupted by a longer-term trend. The overall pattern is that southern African West and South coast shelf waters are becoming warmer, except for some upwelling areas, where cooling is evident. Benguela and Agulhas Bank shelf water are also becoming more oxygen depleted.

scholarly journals Functional redundancy in polychaete assemblages from a tropical Large Marine Ecosystem (LME)

Zoosymposia ◽  
2020 ◽  
Vol 19 (1) ◽  
pp. 72-90
Author(s):  
BARBARA C.G. GIMENEZ ◽  
PAULO LANA
Keyword(s):  
Continental Shelf ◽  
Marine Ecosystem ◽  
Functional Redundancy ◽  
Estuarine Environment ◽  
Environmental Drivers ◽  
Unique Combination ◽  
Marine Life ◽  
Low Level ◽  
Large Marine Ecosystem ◽  
South Brazil

Functional redundancy assumes a critical relevance nowadays due to the serious threats that affect marine life worldwide. We assessed and compared levels of functional redundancy in polychaete assemblages from the continental shelf and from estuarine environments along the South Brazil Shelf Large Marine Ecosystem (SBSLME). To quantify functional redundancy, we used functional originality (FOri) and functional uniqueness (FUni). We found 57 and 47 polychaete taxa distributed in 48 and 41 functional entities (i.e., a unique combination of trait values) in continental shelf and estuarine environments, respectively. Results suggest a low level of functional redundancy in both environments. However, FOri was higher in the estuarine environment, whereas FUni was higher in the continental shelf. As expected, estuarine polychaetes have fewer unique combinations of trait values, but these combinations are more original and adequate to the varying conditions imposed by estuarine environmental drivers.

scholarly journals Diel Variations in Survey Catch Rates and Survey Catchability of Spiny Dogfish and their Pelagic Prey in the Northeast U.S. Continental Shelf Large Marine Ecosystem

2016 ◽  
Vol 8 (1) ◽  
pp. 244-262 ◽  
Author(s):  
Skyler R. Sagarese ◽  
Michael G. Frisk ◽  
Robert M. Cerrato ◽  
Kathy A. Sosebee ◽  
John A. Musick ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Marine Ecosystem ◽  
Spiny Dogfish ◽  
Diel Variations ◽  
Large Marine Ecosystem ◽  
Pelagic Prey ◽  
Catch Rates

Isotopic characterization of lifetime movement by two demersal fishes from the northeastern Gulf of Mexico

2021 ◽  
Vol 657 ◽  
pp. 161-172
Author(s):  
JL Vecchio ◽  
JL Ostroff ◽  
EB Peebles
Keyword(s):  
Gulf Of Mexico ◽  
Continental Shelf ◽  
Life Histories ◽  
Linear Mixed Model ◽  
Trophic Position ◽  
Eye Lens ◽  
Outer Continental Shelf ◽  
Red Grouper ◽  
Lens Diameter ◽  
Isotopic Characterization

An understanding of lifetime trophic changes and ontogenetic habitat shifts is essential to the preservation of marine fish species. We used carbon and nitrogen stable isotope values (δ13C and δ15N) recorded within the laminar structure of fish eye lenses, reflecting both diet and location over time, to compare the lifetime trends of 2 demersal mesopredators. Tilefish Lopholatilus chamaeleonticeps inhabit burrows on the outer continental shelf, which results in exceptional site fidelity. Red grouper Epinephelus morio are spawned on the middle to outer continental shelf, move to the inner shelf for the juvenile period, and return offshore upon sexual maturity. Both species inhabit the eastern Gulf of Mexico, a region with a distinctive offshore-inshore gradient in background δ13C values. Within individual tilefish (n = 36), sequences of δ13C values and δ15N values had strong, positive correlations with eye-lens diameter, and strong correlations between the 2 isotopes (mean Spearman r = 0.86), reflecting an increase in trophic position with growth and little lifetime movement. In red grouper (n = 30), δ15N values positively correlated with eye-lens diameter, but correlations between δ15N and δ13C were weak (mean Spearman r = 0.29), suggesting cross-shelf ontogenetic movements. Linear mixed model results indicated strong relationships between δ15N and δ13C values in tilefish eye lenses but no convergence in the red grouper model. Collectively, these results are consistent with previously established differences in the life histories of the 2 species, demonstrating the potential utility of eye-lens isotope records, particularly for investigating the life histories of lesser-known species.

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