Spatio-temporal variability in the distribution of epi- and meso-pelagic acoustic backscatter in the Irminger Sea, North Atlantic, with implications for predation on Calanus finmarchicus

Anderson, C. I. H.; Brierley, Andrew S.; Armstrong, Frederick H.

doi:10.1007/s00227-004-1510-8

Cited by 40 publications

(27 citation statements)

References 26 publications

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“…In the same region, Anderson et al (2005) showed integrated values for the 0-800 m water column during daytime in the same range (∼600-2,000 m 2 nmi −2 ). The values of Magnússon (1996) and Anderson et al (2005) are considerably above values for the region west and north of Svalbard and also generally higher than the average values for transects found in the south-eastern part of the Norwegian Sea around 62-64 • N and 3-6 • E (Melle et al, 1993;Knutsen and Serigstad, 2001). The Irminger Sea values are for the whole water column and are not entirely comparable to those of Melle et al (1993).…”

Section: Key Features Along Acoustic Transectsmentioning

confidence: 55%

“…Although acoustics are regularly used to map the distribution of pelagic fish both in the Norwegian and Barents Seas (Toresen et al, 1998;Michalsen et al, 2013), there are only a restricted number of studies around the northern Atlantic where acoustic techniques have been applied in open ocean regions to examine large-scale acoustic backscattering structures (Melle et al, 1993;Kaartvedt et al, 1996Kaartvedt et al, , 1998Magnússon, 1996;Torgersen et al, 1997;Dale et al, 1999;Knutsen and Serigstad, 2001;Anderson et al, 2005;Pepin, 2013;Norheim et al, 2016;Siegelman-Charbit and Planque, 2016). Most studies have focused on the more accessible fjord populations of fish and plankton, addressing Frontiers in Marine Science | www.frontiersin.orgspecific issues related to predator prey interactions and diel vertical migration (Falk-Petersen et al, 2004;Kaartvedt et al, 2008;Berge et al, 2009Berge et al, , 2014Dypvik et al, 2012).…”

Section: Discussionmentioning

confidence: 99%

“…The Irminger Sea values are for the whole water column and are not entirely comparable to those of Melle et al (1993). However, Anderson et al (2005) reported daytime values in the 0-200 m layer that in most instances were <62 m 2 nmi −2 , while night-time values ranged from 42 to 235.8 m 2 nmi −2 , indicating that they are on the order of 10-100 times lower than the total water column (0-800 m) backscattering, thus emphasizing the importance and magnitude of the DSL itself.…”

Section: Key Features Along Acoustic Transectsmentioning

confidence: 92%

“…The importance of light during the mid-night sun period in summer in restricting high Arctic mesopelagic fish diel vertical migrations for safe foraging at shallow depths has also been emphasized (Kaartvedt, 2008). Such potential restrictions in the feeding excursion could also apply to other types of organisms that are normally associated with DSLs in the Norwegian Sea (Melle et al, 1993;Torgersen et al, 1997;Kaartvedt et al, 1998;Knutsen and Serigstad, 2001), the Irminger Sea (Magnússon, 1996;Sigurðsson et al, 2002;Anderson et al, 2005), and the Labrador Sea (Pepin, 2013;Fennell and Rose, 2015).…”

Section: Introductionmentioning

confidence: 99%

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High Latitude Epipelagic and Mesopelagic Scattering Layers—A Reference for Future Arctic Ecosystem Change

et al. 2017

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Scattering structures, including deep (>200 m) scattering layers are common in most oceans, but have not previously been properly documented in the Arctic Ocean. In this work, we combine acoustic data for distribution and abundance estimation of zooplankton and fish with biological sampling from the region west and north of Svalbard, to examine high latitude meso-and epipelagic scattering layers and their biological constituents. Our results show that typically, there was strong patchy scattering in the upper part of the epipelagic zone (<50 m) throughout the area. It was mainly dominated by copepods, krill, and amphipods in addition to 0-group fish that were particularly abundant west of the Spitsbergen Archipelago. Off-shelf there was a distinct deep scattering layer (DSL) between 250 and 600 m containing a range of larger longer lived organisms (mesopelagic fish and macrozooplankton). In eastern Fram Strait, the DSL also included and was in fact dominated by larger fish close to the shelf/slope break that were associated with Warm Atlantic Water moving north toward the Arctic Ocean, but switched to dominance by species having weaker scattering signatures further offshore. The Weighted Mean Depths of the DSL were deeper (WMD > 440 m) in the Arctic habitat north of Svalbard compared to those south in the Fram Strait west of Svalbard (WMD ∼400 m). The surface integrated backscatter [Nautical Area-Scattering Coefficient, NASC, s A (m 2 nmi −2 )] was considerably lower in the waters around Svalbard compared to the more southern regions (62-69 • N). Also, the integrated DSL nautical area scattering coefficient was a factor of ∼6-10 lower around Svalbard compared to the areas in the south-eastern part of the Norwegian Sea ∼62 • 30 ′ N. The documented patterns and structures, particularly the DSL and its constituents, will be key reference points for understanding and quantifying future changes in the pelagic ecosystem at the entrance to the Arctic Ocean.

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Section: Key Features Along Acoustic Transectsmentioning

confidence: 55%

Section: Discussionmentioning

confidence: 99%

Section: Key Features Along Acoustic Transectsmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

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High Latitude Epipelagic and Mesopelagic Scattering Layers—A Reference for Future Arctic Ecosystem Change

et al. 2017

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“…Our results showed that, despite this continuity in survey design and timing, there were distinct inter-annual variations in school size, depth and horizontal distribution. shown that there is a distinct seasonal deepening of acoustic scattering layers in the wintertime at high latitudes that could be related to a corresponding seasonal deepening of food resources, such as small zooplankton (Anderson et al, 2005;Chereskin and Tarling, 2007). Distinct seasonal deepening of myctophid schools was also reported by across the Scotia Sea.…”

Section: Inter-annual Variation In Myctophid Schools At Sgmentioning

confidence: 77%

School characteristics of mesopelagic fish at South Georgia

Saunders

Fielding

Thorpe

et al. 2013

Deep Sea Research Part I: Oceanographic Research Papers

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In this paper, we describe the variation in myctophid schools characteristics at South Georgia using multi-frequency acoustic data collected annually between November 2007 and January 2012. We studied the relationship between the proximity of land and the distribution and schooling characteristics of myctophid fish. We also examined patterns in schooling behaviour in relation to oceanographic data. Fish schools were identified using a dualfrequency dB identification method (S v120-38 kHz ), where negative S v120-38 kHz is indicative of gas-bearing organisms, such as swimbladdered fish. Available net data were used to provide information on the meosopelagic fish community in the region. School morphometrics (e.g. length, thickness, area) data were extracted and pooled according to their distance from the shore (0-30 km, 30-60 km, 60-90 km, 90-120 km). A total of 578 schools were detected in the survey region and there was high variation in school backscattering strength (NASC), length, height, perimeter, depth and horizontal distribution between surveys, including distinct inter-annual variation in these parameters when surveys were conducted in the same season (2009)(2010)(2011)(2012). Schools were distributed predominantly on-shelf (0-500 m isobaths) during some summer surveys (2007 and 2012) and predominantly off-shelf on others (>500 2 m isobaths; 2009, 2010 and 2011). There was also evidence of bathymetric separation in the horizontal distribution of schools. Schools observed in the late-season in 2008 had the greatest NASC, largest height and the deepest depth distribution. Most schools occurred at depths between ~60-300 m, but they did not occupy the same water masses during each survey. Schools became progressively thinner, shallower and acoustically weaker with increasing distance to land, whilst school length and perimeter increased correspondingly.The change in fish schooling behaviour between environments could be a response to a combination of local predatory threats over short spatial/temporal scales and differences in oceanographic conditions, such as current velocity. The trend could also be evidence of spatial habitat partitioning of myctophids, with different schooling species, or different lifestages, orientating along a bathymetric gradient at South Georgia.

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The carrying capacity of the seas and oceans for future sustainable food production: Current scientific knowledge gaps

Meer

Callier

Fabi

et al. 2023

Food and Energy Security

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The expected increase in global food demand, as a consequence of a rising and wealthier world population, and an awareness of the limits and drawbacks of modern agriculture, has resulted in a growing attention to the potential of the seas and oceans to produce more food. The capture production of presently exploited marine fish stocks and other species has more or less reached its maximum and can only be slightly improved by better management. This leaves four alternative options open to increase marine food production: (1) manipulating the entire food web structure via removal of high trophic level species to allow an increasing exploitation of low trophic level species, (2) harvesting so far unexploited stocks, such as various fish species from the mesopelagic zone of the ocean or the larger zooplankton species from polar regions, (3) low-trophic mariculture of seaweeds and herbivorous animals, and (4) restoration of impoverished coastal ecosystems or artificially increasing productivity by ecological engineering. In this paper, we discuss these four options and pay attention to missing scientific knowledge needed to assess their sustainability. To assess sustainability, it is a prerequisite to establish robust definitions and assessments of the biological carrying capacity of the systems, but it is also necessary to evaluate broader socio-economic and governance sustainability.

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Spatio-temporal variability in the distribution of epi- and meso-pelagic acoustic backscatter in the Irminger Sea, North Atlantic, with implications for predation on Calanus finmarchicus

Cited by 40 publications

References 26 publications

High Latitude Epipelagic and Mesopelagic Scattering Layers—A Reference for Future Arctic Ecosystem Change

High Latitude Epipelagic and Mesopelagic Scattering Layers—A Reference for Future Arctic Ecosystem Change

School characteristics of mesopelagic fish at South Georgia

The carrying capacity of the seas and oceans for future sustainable food production: Current scientific knowledge gaps

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