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

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.

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2013-0342 ◽

2014 ◽

Vol 71 (6) ◽

pp. 847-877 ◽

Cited By ~ 33

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.

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

Fishery Bulletin ◽

10.7755/fb.113.2.1 ◽

2015 ◽

Vol 113 (2) ◽

pp. 101-120 ◽

Cited By ~ 3

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

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2013-0259 ◽

2014 ◽

Vol 71 (4) ◽

pp. 567-580 ◽

Cited By ~ 11

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.

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Leopard Seals (Hydrurga leptonyx) in New Zealand Waters Predating on Chondrichthyans

Frontiers in Marine Science ◽

10.3389/fmars.2021.795358 ◽

2021 ◽

Vol 8 ◽

Author(s):

Krista van der Linde ◽

Ingrid N. Visser ◽

Rick Bout ◽

Chris Lalas ◽

Lara Shepherd ◽

...

Keyword(s):

New Zealand ◽

Dna Sequencing ◽

High Frequency ◽

Marine Ecosystem ◽

Marine Ecosystems ◽

Squalus Acanthias ◽

Spiny Dogfish ◽

Frequency Of Occurrence ◽

Morphological Examination ◽

Hydrurga Leptonyx

Leopard seals (Hydrurga leptonyx) are top-order predators that prey on a wide variety of species including crustaceans, cephalopods, fishes, birds, and pinnipeds. While multiple diet studies have been conducted worldwide, there are no previous accounts of leopard seals predating on chondrichthyans. As part of a wider study on the diet of leopard seals in New Zealand (NZ) waters, researchers and citizen scientists recorded 39 observations of predation and collected 127 scats (166 total records) between 1942 and 2019. Predation on chondrichthyans was detected in 23.1% (n = 9) of observations of predation and 7.1% (n = 9) of scats (the latter via morphological examination and DNA sequencing). From both observations of predations and scats, three chondrichthyan species or genus were identified; elephantfish (Callorhinchus milii), ghost sharks (Hydrolagus spp.) and spiny dogfish (Squalus acanthias). While this is the first published record of leopard seals feeding on chondrichthyans, the relatively high frequency of occurrence within our NZ records, and that certain individuals appeared to target this type of prey, indicates that these species could constitute a substantial, or important, part of the diet for some leopard seals in this region. As chondrichthyans form an important part of the NZ marine ecosystems, our recognition of an additional top-order predator of these species contributes to understanding the overall health of, and future impacts of predators on, the wider NZ marine ecosystem.

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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

Marine and Coastal Fisheries ◽

10.1080/19425120.2015.1135219 ◽

2016 ◽

Vol 8 (1) ◽

pp. 244-262 ◽

Cited By ~ 5

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

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The Gulf of Guinea Large Marine Ecosystem - Environmental Forcing & Sustainable Development of Marine Resources

10.1016/s1570-0461(02)x8018-5 ◽

2002 ◽

Keyword(s):

Sustainable Development ◽

Marine Ecosystem ◽

Marine Resources ◽

Gulf Of Guinea ◽

Environmental Forcing ◽

Large Marine Ecosystem

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Pilot-scale combustion studies with kraft lignin in a powder burner and a CFB boiler

TAPPI Journal ◽

10.32964/tj9.6.24 ◽

2010 ◽

Vol 9 (6) ◽

pp. 24-30 ◽

Cited By ~ 2

Author(s):

NIKLAS BERGLIN ◽

PER TOMANI ◽

HASSAN SALMAN ◽

SOLVIE HERSTAD SVÄRD ◽

LARS-ERIK ÅMAND

Keyword(s):

Circulating Fluidized Bed ◽

Black Liquor ◽

Chloride Content ◽

Pilot Scale ◽

High Energy ◽

Kraft Lignin ◽

High Energy Density ◽

Alkali Chloride ◽

Cfb Boiler ◽

Solid Biofuel

Processes have been developed to produce a solid biofuel with high energy density and low ash content from kraft lignin precipitated from black liquor. Pilot-scale tests of the lignin biofuel were carried out with a 150 kW powder burner and a 12 MW circulating fluidized bed (CFB) boiler. Lignin powder could be fired in a powder burner with good combustion performance after some trimming of the air flows to reduce swirl. Lignin dried to 10% moisture content was easy to feed smoothly and had less bridging tendencies in the feeding system than did wood/bark powder. In the CFB boiler, lignin was easily handled and cofired together with bark. Although the filter cake was broken into smaller pieces and fines, the combustion was not disturbed. When cofiring lignin with bark, the sulfur emission increased compared with bark firing only, but most of the sulfur was captured by calcium in the bark ash. Conventional sulfur capture also occurred with addition of limestone to the bed. The sulfur content in the lignin had a significantly positive effect on reducing the alkali chloride content in the deposits, thus reducing the high temperature corrosion risk.

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