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

scholarly journals Bounds on Biomass Estimates and Energetic Consequences of Ctenophora in the Northeast U.S. Shelf Ecosystem

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Michael D. Ford ◽  
Jason S. Link
Keyword(s):  
Feeding Strategy ◽  
Marine Ecosystem ◽  
High Energy ◽  
Gelatinous Zooplankton ◽  
Squalus Acanthias ◽  
High Energy Density ◽  
Spiny Dogfish ◽  
Sampling Device ◽  
Large Marine Ecosystem ◽  
Major Increase

Previous descriptions have noted that the stomach samples of spiny dogfish, Squalus acanthias, showed a major increase in the overall occurrence and hence implied abundance of Ctenophora. This apparent and persistent gelatinous zooplankton outbreak is increasingly more common in the world’s oceans. We briefly explore the energetic ramifications of ctenophores in the spiny dogfish diet, inferring that the presence of gelatinous zooplankton represents an ambient feeding strategy. Relative to other prey, ctenophores are not a high energy density prey item. However, given varying assumptions of the amount of ctenophores consumed, they may be an important staple in the diet of spiny dogfish. We also examine the utility of using spiny dogfish as a gelatinous zooplankton sampling device. Using five calculation methodologies, we provide bounds on potential abundance and biomass estimates of ctenophores in the Northeast U.S. shelf ecosystem. We then contextualize these findings relative to the implications for the Northeast U.S. and any large marine ecosystem.

Influence of environmental, spatial, and ontogenetic variables on habitat selection and management of spiny dogfish in the Northeast (US) shelf large marine ecosystem

2014 ◽  
Vol 71 (4) ◽  
pp. 567-580 ◽  
Author(s):  
Skyler R. Sagarese ◽  
Michael G. Frisk ◽  
Thomas J. Miller ◽  
Kathy A. Sosebee ◽  
John A. Musick ◽  
...  
Keyword(s):  
Habitat Selection ◽  
Environmental Conditions ◽  
Statistical Power ◽  
Stock Assessment ◽  
Marine Ecosystem ◽  
Spiny Dogfish ◽  
Trawl Survey ◽  
Science Center ◽  
Large Marine Ecosystem ◽  
Northeast Us

Declines in abundance of commercially valuable groundfish have highlighted the ecological and commercial importance of previously underutilized elasmobranchs in the Northeast (US) shelf large marine ecosystem (NES LME). Seasonal distributions and ontogenetic habitats of one such species, spiny dogfish (Squalus acanthias), were investigated using Northeast Fisheries Science Center (NEFSC) bottom trawl survey data (1963–2009). Neonate, immature, and mature dogfish all selected warmer, more saline, and more southerly locations during spring compared with available locations. During autumn, larger dogfish occupied relatively warmer, shallower, and less saline waters while neonates selected higher salinities. There were strong ontogenetic patterns in habitats occupied. Contrary to expectation, geographic range contracted as abundance increased during autumn. This suggests that niche constraints override density-dependent effects, although detection of relationships within stages was limited by low statistical power. The proportion of mature female survey catch within the Mid-Atlantic Bight was significantly related to temperature, suggesting that environmental conditions surveyed may impact population trends. Collectively, these results highlight critical habitats, suggest mechanisms behind ontogenetic habitat selection, and provide insight into how changing environmental conditions may impact stock assessment.

Application of generalized additive models to examine ontogenetic and seasonal distributions of spiny dogfish (Squalus acanthias) in the Northeast (US) shelf large marine ecosystem

2014 ◽  
Vol 71 (6) ◽  
pp. 847-877 ◽  
Author(s):  
Skyler R. Sagarese ◽  
Michael G. Frisk ◽  
Robert M. Cerrato ◽  
Kathy A. Sosebee ◽  
John A. Musick ◽  
...  
Keyword(s):  
Generalized Additive Models ◽  
Marine Ecosystem ◽  
Additive Models ◽  
Squalus Acanthias ◽  
Seasonal Occurrence ◽  
Spiny Dogfish ◽  
Science Center ◽  
Large Marine Ecosystem ◽  
Northeast Us ◽  
The Relationship

Increased commercial importance of spiny dogfish (Squalus acanthias) combined with an often debated, and controversial, ecological impact has warranted an investigation of the relationship among distribution, environment, and prey to better understand the species ecology and inform management. To elucidate mechanisms behind distributional changes, we modeled seasonal occurrence and abundance of neonate, immature, and mature spiny dogfish as functions of abiotic and biotic factors using generalized additive models and Northeast Fisheries Science Center bottom trawl survey data. Significant nonlinear relationships were widespread throughout dogfish stages and seasons. Seasonal occurrence was tightly linked to depth and bottom temperature, with year and Julian day influential for some stages. While these factors also influenced abundance, ecological factors (e.g., squid abundances) significantly contributed to trends for many stages. Potential impacts of climate change were evaluated by forecasting distributions under different temperature scenarios, which revealed higher regional probabilities of occurrence for most stages during a warmer than average year. Our results can be used to better understand the relationship between sampling periods and movement drivers to survey catchability of the population in the Northeast (US) shelf large marine ecosystem.

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 Spatiotemporal overlap of spiny dogfish (Squalus acanthias) and commercial fisheries in the northeast U.S. shelf large marine ecosystem

2015 ◽  
Vol 113 (2) ◽  
pp. 101-120 ◽  
Author(s):  
Skyler R. Sagarese ◽  
Michael G. Frisk ◽  
Robert M. Cerrato ◽  
Kathy A. Sosebee ◽  
John A. Musick ◽  
...  
Keyword(s):  
Marine Ecosystem ◽  
Squalus Acanthias ◽  
Commercial Fisheries ◽  
Spiny Dogfish ◽  
Large Marine Ecosystem

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.

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