Bloom or bust: synchrony in jellyfish abundance, fish consumption, benthic scavenger abundance, and environmental drivers across a continental shelf

2016 ◽  
Vol 25 (5) ◽  
pp. 500-514 ◽  
Author(s):  
Brian E. Smith ◽  
Michael D. Ford ◽  
Jason S. Link
Keyword(s):  
Continental Shelf ◽  
Fish Consumption ◽  
Environmental Drivers ◽  
Jellyfish Abundance

scholarly journals Spatial variability of Chondrichthyes in the northern Mediterranean

2020 ◽  
Vol 83 (S1) ◽  
pp. 81 ◽  
Author(s):  
Maria C. Follesa ◽  
Martina F. Marongiu ◽  
Walter Zupa ◽  
Andrea Bellodi ◽  
Alessandro Cau ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Generalized Additive Models ◽  
Regional Scale ◽  
Additive Models ◽  
Environmental Drivers ◽  
Shark Species ◽  
Fishing Pressure ◽  
The Mediterranean ◽  
High Level ◽  
Management And Conservation

Thanks to the availability of the MEDITS survey data, a standardized picture of the occurrence and abundance of demersal Chondrichthyes in the northern Mediterranean has been obtained. During the spring-summer period between 2012 and 2015, 41 Chondrichthyes, including 18 sharks (5 orders and 11 families), 22 batoids (3 orders and 4 families) and 1 chimaera, were detected from several geographical sub-areas (GSAs) established by the General Fisheries Commission for the Mediterranean. Batoids had a preferential distribution on the continental shelf (10-200 m depth), while shark species were more frequent on the slope (200-800 m depth). Only three species, the Carcharhiniformes Galeus melastomus and Scyliorhinus canicula and the Torpediniformes Torpedo marmorata were caught in all GSAs studied. On the continental shelf, the Rajidae family was the most abundant, being represented in primis by Raja clavata and then by R. miraletus, R. polystigma and R. asterias. The slope was characterized by the prevalence of G. melastomus in all GSAs, followed by S. canicula, E. spinax and Squalus blainville. Areas under higher fishing pressure, such as the Adriatic Sea and the Spanish coast (with the exception of the Balearic Islands), show a low abundance of chondrichthyans, but other areas with a high level of fishing pressure, such as southwestern Sicily, show a high abundance, suggesting that other environmental drivers work together with fishing pressure to shape their distribution. Results of generalized additive models highlighted that depth is one of the most important environmental drivers influencing the distribution of both batoid and shark species, although temperature also showed a significant influence on their distribution. The approach explored in this work shows the possibility of producing maps modelling the distribution of demersal chondrichthyans in the Mediterranean that are useful for the management and conservation of these species at a regional scale. However, because of the vulnerability of these species to fishing exploitation, fishing pressure should be further incorporated in these models in addition to these environmental drivers.

The continental shelf benthic ecosystem: current status, agents for change and future prospects

2002 ◽  
Vol 29 (3) ◽  
pp. 350-374 ◽  
Author(s):  
Stephen J. Hall
Keyword(s):  
Land Use ◽  
Continental Shelf ◽  
Waste Disposal ◽  
Sustainable Use ◽  
Well Being ◽  
Developed Countries ◽  
Ecological Condition ◽  
Social Consequences ◽  
Environmental Drivers ◽  
Current Status

Continental shelf benthic ecosystems play an important role in the economy of many coastal states through the provision of food, non-living resources and through control of climate. Changes in the status of these ecosystems, through either natural or human-induced environmental drivers can be expected to have important economic and social consequences. Agents that could induce change include climate and oceanography, hydrology (river discharge), land-use and waste disposal practices, fishing, aquaculture and extraction of non-living resources. Trends in all of these drivers, particularly those under human influence, suggest that shelf systems will come under increasing pressure. Attempts to predict the future state of any ecological system are fraught with difficulty, particularly over decadal time-frames. This is, perhaps, especially true for continental shelf ecosystems where data on current status are poor and our understanding of many of the drivers of change somewhat rudimentary. What can be said for certain, however, is that change will occur and, in the short term, many of the signs point towards deterioration in the ecological condition of many shelf systems, but particularly those of developing countries. Trends in land-use practices, with consequences for nutrient, sediment and freshwater input to coastal seas appear to be particularly worrying, but the poor state of many demersal fisheries systems must also be acknowledged. In contrast to the developing world, although challenges undoubtedly remain, particularly with respect to atmospheric inputs resulting from energy production, current trends in environmental management suggest that pressures imposed by land use, waste disposal and fishing will probably decline over the coming decades on the shelves of many developed countries. At the global scale, therefore, the key driver for sustainable use of our continental shelf ecosystems would appear to be intimately linked to the social and economic well-being of poorer nations.

Benthic hotspots on the northern Bering and Chukchi continental shelf: Spatial variability in production regimes and environmental drivers

2021 ◽  
Vol 191 ◽  
pp. 102497
Author(s):  
Zhixuan Feng ◽  
Rubao Ji ◽  
Carin Ashjian ◽  
Jinlun Zhang ◽  
Robert Campbell ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Continental Shelf ◽  
Environmental Drivers

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 Food web structure in relation to environmental drivers across a continental shelf ecosystem

2021 ◽  
Author(s):  
Andrea Walters ◽  
Marianne Robert ◽  
Pierre Cresson ◽  
Hervé Le Bris ◽  
Dorothée Kopp
Keyword(s):  
Continental Shelf ◽  
Food Web ◽  
Environmental Drivers ◽  
Food Web Structure ◽  
Web Structure

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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