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

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.

2016 ◽  
Author(s):  
F. Hu ◽  
K. Bolding ◽  
J. Bruggeman ◽  
E. Jeppesen ◽  
M. R. Flindt ◽  
...  

Abstract. This study presents FABM-PCLake, a complete redesign of the PCLake aquatic ecosystem model, which we implemented into the Framework for Aquatic Biogeochemical Models (FABM). In contrast to the original model, which was designed for temperate, fully mixed freshwater lakes, the new FABM-PCLake represents an integrated aquatic ecosystem model that enables simulations of hydrodynamics and biogeochemical processes for zero dimensional, one-dimensional as well as three-dimensional heterogeneous environments. FABM-PCLake describes interactions between multiple trophic levels, including piscivorous, zooplanktivorous and benthivorous fish, zooplankton, zoobenthos, three groups of phytoplankton and rooted macrophytes. The model also accounts for oxygen dynamics and nutrient cycling for nitrogen, phosphorus and silicon, both within the pelagic and benthic domains. FABM-PCLake includes a two-way communication between the biogeochemical processes and the physics, where some biogeochemical state variables (e.g., phytoplankton) influence light attenuation and thereby the spatial and temporal distributions of light and heat. At the same time, the physical environment, including water currents, light and temperature influence a wide range of biogeochemical processes. The model enables studies on ecosystem dynamics in physically heterogeneous environments (e.g., stratifying water bodies, and water bodies with horizontal gradient in physical and biogeochemical properties), and through FABM also enables data assimilation and multi-model ensemble simulations. Examples of relevant model applications include climate change impact studies and environmental impact assessment scenarios for lakes and reservoirs worldwide.


2007 ◽  
Vol 79 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Alexandre L. Pereira ◽  
Evanilde Benedito ◽  
Cássia M. Sakuragui

Stable isotopes of carbon (delta13C) and nitrogen (delta15N) were used to describe sources of energy and trophic position for adult Leporinus friderici in the area of the Corumbá Reservoir, Brazil. Samples were collected from April 1999 to March 2000. Spatial variations were not identified in the isotopic composition. The maximum and minimum contribution of C4 plants calculated integrating the variation of plants and fish were 47.7% and 2.4%, respectively. Among C3 plants, periphyton presented closer isotopic values to those observed for fishes, corresponding to an important carbon source. The proportion of ingested plant item is larger in rivers upstream from the reservoir (42.7%), which justifies the smaller trophic level among there. However, in the reservoir, the ingestion of fish was 81.4%, while ingested plants contributed with 18.6%. Downstream from the dam, participation of plant item was even smaller (14.4%). Although the trophic position calculated with diet data was proportional to the one calculated with delta15N values, the former elevated the trophic level of L. friderici in the food web, because estimated trophic positions were based on fish items belonging to the 2nd (a) and to the 3rd (b) trophic levels.


2020 ◽  
Vol 233 ◽  
pp. 106518
Author(s):  
Jianguo Du ◽  
Petrus Christianus Makatipu ◽  
Lily S.R. Tao ◽  
Daniel Pauly ◽  
William W.L. Cheung ◽  
...  

2010 ◽  
Vol 68 (3) ◽  
pp. 547-554 ◽  
Author(s):  
Asunción Borrell ◽  
Luis Cardona ◽  
Ramanathan P. Kumarran ◽  
Alejandro Aguilar

Abstract Borrell, A., Cardona, L., Kumarran, R. P., and Aguilar, A. 2011. Trophic ecology of elasmobranchs caught off Gujarat, India, as inferred from stable isotopes. – ICES Journal of Marine Science, 68: . Habitat use and trophic levels were investigated in 13 species of elasmobranch caught off Gujarat, India, through their isotopic composition. Most of the animals were fished commercially and were immature, suggesting that fisheries operate in nursery habitats. All of the sharks analysed except Rhincodon typus had a higher estimated trophic level (>3.8) than rays and guitarfish (<3.8), suggesting a diet of bony fish and cephalopods. The trophic level of Sphyrna lewini and R. typus increased with total length, indicating ontogenetic dietary shifts, but the other species did not follow this trend. According to their δ13C values, R. typus, Mobula diabolus, and, surprisingly, Rhina ancylostoma appeared to be the most pelagic species. In comparison, Stegostoma fasciatum, Pristis pectinata, Rhinobatos granulatus, and Aetomylaeus maculatus appeared to be the most demersal, inshore species, and their δ13C signatures were significantly different from those of the three aforementioned species.


2016 ◽  
Vol 17 (2) ◽  
pp. 496 ◽  
Author(s):  
J. J. De LOPE ARIAS ◽  
G. MATEU-VICENS ◽  
M. DEUDERO COMPANY

Stable isotopes (δ15N) are used to determine trophic level in marine food webs. We assessed if Marine Protected Areas (MPAs) affect trophic level of fishes based on stable isotopes on the Western Mediterranean. A total of 22 studies including 600 observations were found and the final dataset consisted of 11 fish species and 146 observations comparing trophic level inside and outside MPAs. The database was analysed by meta-analysis and the covariate selected was the level of protection (inside vs. outside MPAs). The results indicate significant difference between trophic levels inside and outside MPAs. However, results differ from expectations since the trophic level inside was lower than outside MPAs. Three habitats were analysed (coastal lagoons, demersal and littoral) and significant differences were found among them. Trophic level was higher in demersal habitats than in coastal lagoons and littoral areas. No significant differences were found in species classified by trophic functional groups. We consider several hypotheses explaining the obtained results linked to protection level of the MPAs, time since protection and MPAs size. We debate the suitability of using the stable isotope (δ15N) as direct indicator of trophic level in evaluating MPAs effects on food webs.


2016 ◽  
Vol 9 (6) ◽  
pp. 2271-2278 ◽  
Author(s):  
Fenjuan Hu ◽  
Karsten Bolding ◽  
Jorn Bruggeman ◽  
Erik Jeppesen ◽  
Morgens R. Flindt ◽  
...  

Abstract. This study presents FABM-PCLake, a redesigned structure of the PCLake aquatic ecosystem model, which we implemented in the Framework for Aquatic Biogeochemical Models (FABM). In contrast to the original model, which was designed for temperate, fully mixed freshwater lakes, the new FABM-PCLake represents an integrated aquatic ecosystem model that can be linked with different hydrodynamic models and allows simulations of hydrodynamic and biogeochemical processes for zero-dimensional, one-dimensional as well as three-dimensional environments. FABM-PCLake describes interactions between multiple trophic levels, including piscivorous, zooplanktivorous and benthivorous fish, zooplankton, zoobenthos, three groups of phytoplankton and rooted macrophytes. The model also accounts for oxygen dynamics and nutrient cycling for nitrogen, phosphorus and silicon, both within the pelagic and benthic domains. FABM-PCLake includes a two-way communication between the biogeochemical processes and the physics, where some biogeochemical state variables (e.g., phytoplankton) influence light attenuation and thereby the spatial and temporal distributions of light and heat. At the same time, the physical environment, including water currents, light and temperature influence a wide range of biogeochemical processes. The model enables studies on ecosystem dynamics in physically heterogeneous environments (e.g., stratifying water bodies, and water bodies with horizontal gradients in physical and biogeochemical properties), and through FABM also enables data assimilation and multi-model ensemble simulations. Examples of potential new model applications include climate change impact studies and environmental impact assessment scenarios for temperate, sub-tropical and tropical lakes and reservoirs.


2013 ◽  
Vol 19 (1) ◽  
pp. 105-115 ◽  
Author(s):  
Guohuan YANG ◽  
Xingli SUN ◽  
Xiuqiong HOU ◽  
Chunliang CHEN

1994 ◽  
Vol 29 (3) ◽  
pp. 207-209 ◽  
Author(s):  
H. Puzicha

Effluents from point sources (industries, communities) and diffuse inputs introduce pollutants into the water of the river Rhine and cause a basic contaminant load. The aim is to establish a biological warning system to detect increased toxicity in addition to the already existing chemical-physical monitoring system. To cover a wide range of biocides, continuous working biotests at different trophic levels (bacteria, algae, mussels, water fleas, fishes) have been developed and proved. These are checked out for sensitivity against toxicants, reaction time, validity of data and practical handling under field conditions at the river. Test-specific appropriate methods are found to differentiate between the normal range of variation and true alarm signals.


Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1696
Author(s):  
Ridha Ibidhi ◽  
Rajaraman Bharanidharan ◽  
Jong-Geun Kim ◽  
Woo-Hyeong Hong ◽  
In-Sik Nam ◽  
...  

This study was performed to update and generate prediction equations for converting digestible energy (DE) to metabolizable energy (ME) for Korean Hanwoo beef cattle, taking into consideration the gender (male and female) and body weights (BW above and below 350 kg) of the animals. The data consisted of 141 measurements from respiratory chambers with a wide range of diets and energy intake levels. A simple linear regression of the overall unadjusted data suggested a strong relationship between the DE and ME (Mcal/kg DM): ME = 0.8722 × DE + 0.0016 (coefficient of determination (R2) = 0.946, root mean square error (RMSE) = 0.107, p < 0.001 for intercept and slope). Mixed-model regression analyses to adjust for the effects of the experiment from which the data were obtained similarly showed a strong linear relationship between the DE and ME (Mcal/kg of DM): ME = 0.9215 × DE − 0.1434 (R2 = 0.999, RMSE = 0.004, p < 0.001 for the intercept and slope). The DE was strongly related to the ME for both genders: ME = 0.8621 × DE + 0.0808 (R2 = 0.9600, RMSE = 0.083, p < 0.001 for the intercept and slope) and ME = 0.7785 × DE + 0.1546 (R2 = 0.971, RMSE = 0.070, p < 0.001 for the intercept and slope) for male and female Hanwoo cattle, respectively. By BW, the simple linear regression similarly showed a strong relationship between the DE and ME for Hanwoo above and below 350 kg BW: ME = 0.9833 × DE − 0.2760 (R2 = 0.991, RMSE = 0.055, p < 0.001 for the intercept and slope) and ME = 0.72975 × DE + 0.38744 (R2 = 0.913, RMSE = 0.100, p < 0.001 for the intercept and slope), respectively. A multiple regression using the DE and dietary factors as independent variables did not improve the accuracy of the ME prediction (ME = 1.149 × DE − 0.045 × crude protein + 0.011 × neutral detergent fibre − 0.027 × acid detergent fibre + 0.683).


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