scholarly journals Assessment of the Carrying Capacity of Integrated Pond Aquaculture of Portunus trituberculatus at the Ecosystem Level

2021 ◽  
Vol 8 ◽  
Author(s):  
Shipeng Dong ◽  
Fang Wang ◽  
Dongxu Zhang ◽  
Liye Yu ◽  
Weijia Pu ◽  
...  
Keyword(s):  
Trophic Level ◽  
Trophic Levels ◽  
Portunus Trituberculatus ◽  
Integrated Aquaculture ◽  
Pond Aquaculture ◽  
Flow Parameters ◽  
Penaeus Japonicus ◽  
Energy Flows ◽  
Level Ii ◽  
Ecosystem Level

In recent years, integrated pond aquaculture under controlled management has been crucial in improving the supply of aquatic products and ensuring food security. This study constructed two trophic models of integrated pond aquaculture ecosystems of Portunus trituberculatus–Penaeus japonicus (PP) and P. trituberculatus–P. japonicus–Sinonovacula constricta (PPS) using Ecopath with Ecosim software. The energy flows, ecosystem properties, and carrying capacities of the two ecosystems were analyzed and evaluated. The results showed that the ecotrophic efficiency values in the PP and PPS ecosystems were 0.962 and 0.954 for P. trituberculatus and P. japonicus and 0.952 for S. constricta. The effective trophic levels of P. trituberculatus and P. japonicus were 2.065 and 2.027 in the PP system, and those of P. trituberculatus, P. japonicus, and S. constricta were 2.057, 2.018, and 2.010 in the PPS system. The primary productivities of the PP and PPS ecosystems were 2623.79 and 2781.48 g/m2/240 days, with 2.13 and 37.83% of the energy flowing to trophic level II and 97.87 and 62.17% flowing to the detritus, respectively. The total energy of the detritus group was 2900.89 and 2372.98 g/m2/240 days, with 931.02 and 1505.35 g/m2/240 days flowing to trophic level II, respectively. The total primary production/total respiration ratio of the PPS ecosystem (1.632) was lower than that of the PP ecosystem (4.824), indicating that the former had a greater degree of exploitation. At the current feeding level, the carrying capacities of P. trituberculatus and P. japonicus were 65.15 and 47.62 g/m2 in the PP ecosystem, and those of P. trituberculatus, P. japonicus, and S. constricta were 64.96, 48.06, and 100.79 g/m2 in the PPS ecosystem, respectively. At adequate feeding levels, the carrying capacities of P. trituberculatus and P. japonicus were 83.76 and 48.52 g/m2 in the PP ecosystem and 81.82 and 53.44 g/m2 in the PPS ecosystem. The ecotrophic efficiency values and energy flow parameters of the two integrated pond aquaculture ecosystems indicated that S. constricta was a suitable collocation culture species for P. trituberculatus and P. japonicus, and there is room for further improvement in yields of this integrated aquaculture ecosystem.

Relationship between morphometrics and trophic levels in deep-sea fishes

2020 ◽  
Vol 637 ◽  
pp. 225-235 ◽  
Author(s):  
MA Ladds ◽  
MH Pinkerton ◽  
E Jones ◽  
LM Durante ◽  
MR Dunn
Keyword(s):  
Stable Isotopes ◽  
Trophic Level ◽  
Deep Sea ◽  
Strong Relationship ◽  
Ecosystem Model ◽  
Trophic Levels ◽  
Fish Size ◽  
Wide Range ◽  
Gape Size ◽  
Morphological Variables

Marine food webs are structured, in part, by predator gape size. Species found in deep-sea environments may have evolved such that they can consume prey of a wide range of sizes, to maximise resource intake in a low-productivity ecosystem. Estimates of gape size are central to some types of ecosystem model that determine which prey are available to predators, but cannot always be measured directly. Deep-sea species are hypothesized to have larger gape sizes than shallower-water species relative to their body size and, because of pronounced adaptive foraging behaviour, show only a weak relationship between gape size and trophic level. Here we present new data describing selective morphological measurements and gape sizes of 134 osteichthyan and chondrichthyan species from the deep sea (200-1300 m) off New Zealand. We describe how gape size (height, width and area) varied with factors including fish size, taxonomy (class and order within a class) and trophic level estimated from stable isotopes. For deep-sea species, there was a strong relationship between gape size and fish size, better predicted by body mass than total length, which varied by taxonomic group. Results show that predictions of gape size can be made from commonly measured morphological variables. No relationship between gape size and trophic level was found, likely a reflection of using trophic level estimates from stable isotopes as opposed to the commonly used estimates from FishBase. These results support the hypothesis that deep-sea fish are generalists within their environment, including suspected scavenging, even at the highest trophic levels.

scholarly journals Mercury distribution in different tissues and trophic levels of fish from a tropical reservoir, Brazil

2009 ◽  
Vol 7 (4) ◽  
pp. 751-758 ◽  
Author(s):  
Daniele Kasper ◽  
Elisabete Fernandes Albuquerque Palermo ◽  
Ana Carolina Monteiro Iozzi Dias ◽  
Gustavo Luiz Ferreira ◽  
Rafael Pereira Leitão ◽  
...  
Keyword(s):  
Trophic Level ◽  
Total Mercury ◽  
Inorganic Mercury ◽  
Trophic Levels ◽  
Southeastern Brazil ◽  
Organic Form ◽  
Fish Tissues ◽  
Tropical Reservoir ◽  
Level Increase ◽  
Carnivorous Species

Concentrations of organic (OrgHg) and inorganic mercury (InorgHg) were assessed in different fish tissues (liver, muscle, kidney, gut and gonads) and trophic levels collected in an impacted tropical reservoir in southeastern Brazil. Organic mercury concentrations in muscle were remarkably higher in the carnivorous species Hoplias malabaricus and Oligosarcus hepsetus. The ratios of OrgHg in relation to total mercury (%OrgHg) in muscle also varied according to the species trophic level: 93% for carnivores, 84% for omnivores, 73% for algivores/planktivores and 58% for detritivores. The %OrgHg in the gut tissue of carnivores (78%) was much higher than that found in omnivores (30%), possibly reflecting a process of trophic biomagnification in the reservoir. On the other hand, the InorgHg concentrations in muscle decreased with the trophic level increase, suggesting that this form of mercury did not biomagnify through the food web. Gonads contained the least total mercury, and approximately all of this mercury was represented by the organic form (83 to 98%). The kidney and the liver of all fish species contained less than 50% OrgHg. We suggest that the low %OrgHg in the liver is related to different capacities or strategies of OrgHg detoxification by the fish.

scholarly journals Examining predator–prey body size, trophic level and body mass across marine and terrestrial mammals

2014 ◽  
Vol 281 (1797) ◽  
pp. 20142103 ◽  
Author(s):  
Marlee A. Tucker ◽  
Tracey L. Rogers
Keyword(s):  
Community Structure ◽  
Body Size ◽  
Body Mass ◽  
Marine Environment ◽  
Trophic Level ◽  
Marine Mammals ◽  
Trophic Position ◽  
Trophic Levels ◽  
Predator Prey ◽  
Terrestrial Mammals

Predator–prey relationships and trophic levels are indicators of community structure, and are important for monitoring ecosystem changes. Mammals colonized the marine environment on seven separate occasions, which resulted in differences in species' physiology, morphology and behaviour. It is likely that these changes have had a major effect upon predator–prey relationships and trophic position; however, the effect of environment is yet to be clarified. We compiled a dataset, based on the literature, to explore the relationship between body mass, trophic level and predator–prey ratio across terrestrial ( n = 51) and marine ( n = 56) mammals. We did not find the expected positive relationship between trophic level and body mass, but we did find that marine carnivores sit 1.3 trophic levels higher than terrestrial carnivores. Also, marine mammals are largely carnivorous and have significantly larger predator–prey ratios compared with their terrestrial counterparts. We propose that primary productivity, and its availability, is important for mammalian trophic structure and body size. Also, energy flow and community structure in the marine environment are influenced by differences in energy efficiency and increased food web stability. Enhancing our knowledge of feeding ecology in mammals has the potential to provide insights into the structure and functioning of marine and terrestrial communities.

From cells to globe: approaching the dynamics of DMS(P) in the ocean at multiple scales

2004 ◽  
Vol 61 (5) ◽  
pp. 673-684 ◽  
Author(s):  
Rafel Simó
Keyword(s):  
Multiple Scales ◽  
Cellular Level ◽  
Trophic Levels ◽  
Global Ocean ◽  
Surface Mixed Layer ◽  
Sulfur Transfer ◽  
Ocean Level ◽  
Ecosystem Level ◽  
Major Carrier ◽  
The Individual

Major advances in dimethylated sulfur research are being made by approaching its dynamics at multiple scales. At the molecular to cellular level, single-cell techniques in molecular biology allow us to identify the microbes involved in cycling of dimethylated sulfur. Also, we find that dimethylsulfoxide (DMSO) is as ubiquitous as dimethyl sulfoniopropionate (DMSP) in marine plankton, which supports the recent suggestion that both compounds are involved in coping with oxidative stress. At the community level, there is recent evidence for the role of DMSP as a major carrier in organic sulfur transfer and cycling through trophic levels, from phytoplankton to bacteria and to zooplankton through herbivore protozoans. As a consequence, the food web dynamics drive the oceanic emission of atmospheric sulfur. At the ecosystem level, the diverse and intricate effects of the physicochemical setting (light, wind, nutrients) on the oceanic cycling of dimethylated sulfur are being uncovered. A proposed shortcut to detailed understanding of the individual processes presents the depth of the surface mixed layer as the variable that integrates most of the environmental effects and serves for predicting dimethylsulfide (DMS) concentrations, even at the global ocean level. This opens the door to assessing the strength of the DMS biogeophysical system as a climate regulator.

scholarly journals Trophic cascades alter eco-evolutionary dynamics and body size evolution

2020 ◽  
Vol 287 (1938) ◽  
pp. 20200526
Author(s):  
Thomas M. Luhring ◽  
John P. DeLong
Keyword(s):  
Body Mass ◽  
Trophic Level ◽  
Evolutionary Dynamics ◽  
Trophic Cascades ◽  
Trophic Levels ◽  
Chain Model ◽  
Top Predator ◽  
Predator Prey ◽  
Top Predators ◽  
Time Changes

Trait evolution in predator–prey systems can feed back to the dynamics of interacting species as well as cascade to impact the dynamics of indirectly linked species (eco-evolutionary trophic cascades; EETCs). A key mediator of trophic cascades is body mass, as it both strongly influences and evolves in response to predator–prey interactions. Here, we use Gillespie eco-evolutionary models to explore EETCs resulting from top predator loss and mediated by body mass evolution. Our four-trophic-level food chain model uses allometric scaling to link body mass to different functions (ecological pleiotropy) and is realistically parameterized from the FORAGE database to mimic the parameter space of a typical freshwater system. To track real-time changes in selective pressures, we also calculated fitness gradients for each trophic level. As predicted, top predator loss generated alternating shifts in abundance across trophic levels, and, depending on the nature and strength in changes to fitness gradients, also altered trajectories of body mass evolution. Although more distantly linked, changes in the abundance of top predators still affected the eco-evolutionary dynamics of the basal producers, in part because of their relatively short generation times. Overall, our results suggest that impacts on top predators can set off transient EETCs with the potential for widespread indirect impacts on food webs.

scholarly journals Drivers of trophic amplification of ocean productivity trends in a changing climate

2014 ◽  
Vol 11 (24) ◽  
pp. 7125-7135 ◽  
Author(s):  
C. A. Stock ◽  
J. P. Dunne ◽  
J. G. John
Keyword(s):  
Food Web ◽  
21St Century ◽  
Trophic Level ◽  
Net Primary Production ◽  
Trophic Levels ◽  
The Arctic ◽  
Phytoplankton Production ◽  
Planktonic Food ◽  
Projected Changes ◽  
Zooplankton Growth

Abstract. Pronounced projected 21st century trends in regional oceanic net primary production (NPP) raise the prospect of significant redistributions of marine resources. Recent results further suggest that NPP changes may be amplified at higher trophic levels. Here, we elucidate the role of planktonic food web dynamics in driving projected changes in mesozooplankton production (MESOZP) found to be, on average, twice as large as projected changes in NPP by the latter half of the 21st century under a high emissions scenario in the Geophysical Fluid Dynamics Laboratory's ESM2M–COBALT (Carbon, Ocean Biogeochemistry and Lower Trophics) earth system model. Globally, MESOZP was projected to decline by 7.9% but regional MESOZP changes sometimes exceeded 50%. Changes in three planktonic food web properties – zooplankton growth efficiency (ZGE), the trophic level of mesozooplankton (MESOTL), and the fraction of NPP consumed by zooplankton (zooplankton–phytoplankton coupling, ZPC), explain the projected amplification. Zooplankton growth efficiencies (ZGE) changed with NPP, amplifying both NPP increases and decreases. Negative amplification (i.e., exacerbation) of projected subtropical NPP declines via this mechanism was particularly strong since consumers in the subtropics have limited surplus energy above basal metabolic costs. Increased mesozooplankton trophic level (MESOTL) resulted from projected declines in large phytoplankton production. This further amplified negative subtropical NPP declines but was secondary to ZGE and, at higher latitudes, was often offset by increased ZPC. Marked ZPC increases were projected for high-latitude regions experiencing shoaling of deep winter mixing or decreased winter sea ice – both tending to increase winter zooplankton biomass and enhance grazer control of spring blooms. Increased ZPC amplified projected NPP increases in the Arctic and damped projected NPP declines in the northwestern Atlantic and Southern Ocean. Improved understanding of the physical and biological interactions governing ZGE, MESOTL and ZPC is needed to further refine estimates of climate-driven productivity changes across trophic levels.

How ‘Best’ to Determine Trophic Levels in Archaeological Agricultural Communities

2017 ◽  
Author(s):  
Linda Reynard
Keyword(s):  
Stable Isotope ◽  
Trophic Level ◽  
Nitrogen Isotope ◽  
Isotope Ratios ◽  
Trophic Levels ◽  
Bone Collagen ◽  
Carbon And Nitrogen ◽  
Agricultural Communities ◽  
Plant Remains ◽  
Isotope System

Stable isotope ratios of bone collagen have been used to determine trophic levels in diverse archaeological populations. The longest established and arguably most successful isotope system has been nitrogen, followed by carbon, and more recently hydrogen. These trophic level proxies rely on a predictable change in isotope ratio with each trophic level step; however, this requirement may not always be met, which can lead to difficulties in interpreting archaeological evidence. In agricultural communities, in particular, there are several possible complications to the interpretation of nitrogen and carbon isotopes. Recent approaches to overcome these limitations include better quantification and understanding of the influences on consumer isotope ratios; inclusion of evidence from plant remains; further investigation of apatite δ13C—collagen δ13C spacing in bones; measurement of carbon and nitrogen isotope ratios in individual amino acids, rather than collagen; and development of other stable isotope proxies for trophic level, such as hydrogen isotopes.

Historical changes in mean trophic level of southern Australian fisheries

2014 ◽  
Vol 65 (10) ◽  
pp. 884 ◽  
Author(s):  
Heidi K. Alleway ◽  
Sean D. Connell ◽  
Tim M. Ward ◽  
Bronwyn M. Gillanders
Keyword(s):  
Trophic Level ◽  
Spatial Data ◽  
South Australia ◽  
Trophic Levels ◽  
High Trophic Level ◽  
Fishing Pressure ◽  
Time Line ◽  
The Mean ◽  
Mean Trophic Level ◽  
Catch Statistics

Decreases in the mean trophic level (MTL) of fishery catches have been used to infer reductions in the abundance of high trophic level species caused by fishing pressure. Previous assessments of southern Australian fisheries have been inconclusive. The objectives of the present study were to provide more accurate estimates of MTL using disaggregated taxonomic and spatial data. We applied the model of MTL to fisheries catch statistics for the state of South Australia from 1951 to 2010 and a novel set of historical market data from 1936 to 1946. Results show that from 1951 to 2010, MTL declined by 0.16 of a trophic level per decade; a rate greater than the global average of 0.10 but equivalent to similar regional investigations in other areas. This change is mainly attributable to large increases in catches of sardine, rather than reductions in the catches of high trophic level species. The pattern is maintained when the historical data is included, providing a time line from 1936 to 2010. Our results show a broadening of the catch of lower trophic levels and suggest care in interpretation of MTL of catches because reductions do not necessarily reflect change in high trophic level species by fishing pressure.

The structure of plankton communities

1977 ◽  
Vol 280 (976) ◽  
pp. 485-534 ◽  
Keyword(s):  
Trophic Level ◽  
Size Structure ◽  
Food Limitation ◽  
Relative Size ◽  
Size Composition ◽  
Trophic Levels ◽  
Total Biomass ◽  
Size Dependent ◽  
First Feeding ◽  
Determining Modes

Interactions of herbivorous copepods with their phytoplankton food depend on the size composition of organisms in both trophic levels. A simulation model is used to analyse these size-dependent relations with the following conclusions. 1. Relative size structure of herbivores and their food is more important than total biomass of each trophic level in determining modes of transfer from plants to herbivores. In nearly all cases, in the model, food limitation affects reproduction or the first feeding stage of the nauplii. 2. No single factor emerges as predominant in determining the size structure of both populations. 3. The nature of predation on the herbivores is at least as important in determining both phytoplankton and herbivore size composition as physical or nutrient parameters. 4. The magnitude of the population of the larger herbivores such as Calanus , important as food for fish, depends on their coexistence with the smaller copepod species which control the smaller phytoplankton. 5. Stress on the system, if it affects adversely the smaller herbivores, can lead to the breakdown of the Calanus -diatom component. 6. Prediction of the population structure for both plants and herbivores may be a more attainable objective of theory and more practically important than prediction of total biomass at each trophic level.

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