ANSTO :: Browsing by Author "Saintilan, N"

Browsing by Author "Saintilan, N"

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Allochthonous and autochthonous contributions to carbon accumulation and carbon accumulation and carbon store in southeastern Australian coastal wetlands
(Estuarine, Coastal and Shelf Science, 128, 84-92, 2013-08-10) Saintilan, N; Rogers, K; Mazumder, D; Woodroffe, CD
Estimates of carbon store and carbon accumulation rate in mangrove and saltmarsh are beset by issues of scale and provenance. Estimates at a site do not allow scaling to regional estimates if the drivers of variability are not known. Also, carbon accumulation within soils provides a net offset only if carbon is derived in-situ, or would not otherwise be sequestered. We use a network of observation sites extending across 2000 km of southeastern Australian coastline to determine the influence of geomorphic setting and coastal wetland vegetation type on rates of carbon accumulation, carbon store and probable sources. Carbon accumulation above feldspar marker horizons over a 10-year period was driven primarily by tidal range and position in the tidal frame, and was higher for mangrove and saltmarsh dominated by Juncus kraussii than for other saltmarsh communities. The rate of carbon loss with depth varied between geomorphic settings and was the primary determinant of carbon store. A down-core enrichment in delta C-13 was consistent with an increased relative contribution of mangrove root material to soil carbon, as mangrove roots were found to be consistently enriched compared to leaves. We conclude that while surface carbon accumulation is driven primarily by tidal transport of allocthonous sediment, in-situ carbon sequestration is the dominant source of recalcitrant carbon, and that mangrove and saltmarsh carbon accumulation and store is high in temperate settings, particularly in mesotidal and fluvial geomorphic settings. © 2013, Elsevier Ltd.
Application of isotope mixing models to discriminate dietary sources over small-scale patches in saltmarsh
(Marine Ecology Progress Series, 2013-07-30) Alderson, B; Mazumder, D; Saintilan, N; Zimmerman, K; Mulry, P
Intertidal grazing crabs play an important role in estuarine ecosystems, transforming carbon fixed by autotrophs into forms available to a wide range of consumers. Whether the autotrophic carbon is derived primarily from intertidal vegetation or microalgae is an important question to be resolved, as the modification of estuaries alters the balance between these potential food sources, and restoration efforts are best guided by an understanding of the primary drivers of ecosystem energy flow. We utilised the mosaic of C3 and C4 vegetated patches in a temperate saltmarsh to clarify the relative contributions of potential sources of carbon and nitrogen to the diet of 2 species of grapsid crabs: Paragrapsus laevis and Helograpsis haswellianus. The 2 vegetation communities occupied the same position in relation to tidal elevation. We analysed stable isotopes of carbon (δ13C) and nitrogen (δ15N) to discriminate 3 potential sources of dietary carbon using an IsoSource mixing model: microphytobenthos (MPB); fine benthic organic matter (FBOM); and fresh plant material. We found enrichment of δ13C and depletion of δ15N in crabs sampled from patches of the C4 grass Sporobolus virginicus, consistent with the use of C4 derived carbon compared to those sampled in the C3 chenopod Sarcocornia quinqueflora. However, microphytobenthos was similarly depleted within large patches of S. virginicus, implying uptake of dissolved inorganic carbon originating from plant respiration. Multiple-source mixing (IsoSource) models indicated a primary role for MPB and FBOM in crab diets, with locally derived plant material making little contribution to crab diet. The result contrasts with those of studies from subtropical and tropical systems. © 2013, Inter-Research.
Authenticating genuine Kakadu plum (Terminalia ferdinandiana) powders from fakes using stable isotope analysis and elemental profiling
(Elsevier, 2024-08) Keaney, M; Mazumder, D; Tadros, CV; Crawford, J; Gadd, PS; Saeki, P; Sammut, J; Saintilan, N
Kakadu plum (Terminalia ferdinandiana) is a plant species endemic to northern Australia, attracting increasing consumer interest due to its multiple nutritional qualities. As a consumer product at a premium price point, the Kakadu plum may be susceptible to food fraud. This paper determines the prevalence of food fraud in the e-commerce Kakadu plum market. We applied stable isotope analysis (SIA) and elemental profiling using X-ray fluorescence (XRF) through Itrax to evaluate the authenticity of 13 commercially available Kakadu plum powdered samples purchased from Australian and overseas suppliers against four powdered samples directly provided by First Nations harvesters. Overseas and Australian-sourced powders were found to have distinct isotopic and elemental profiles. All overseas powders showed highly enriched δ13C values indicating they are fakes, not derived from Kakadu plum. Non-metric multi-dimensional scaling (nMDS) of elements also displayed distinct groupings between Australian-sourced and overseas powders, whilst analysis of similarity percentages (SIMPER) differentiated the elemental composition between groups. It was also observed that 89% of overseas products sold as Kakadu plum were deceptively labelled as other products. These results showed food fraud occurred along the supply chain of overseas-sourced product. Given the complexities of multi-national food systems, utilising a combination of stable isotopes and elemental profiling are straightforward applications for detecting fraudulent products. © 2024 Crown Copyright Published by Elsevier Ltd.
Carbon isotope fractionation in the mangrove Avicennia marina has implications for food web and blue carbon research
(Elsevier B. V., 2018-05-31) Kelleway, JJ; Mazumder, D; Baldock, JA; Saintilan, N
The ratio of stable isotopes of carbon (δ13C) is commonly used to track the flow of energy among individuals and ecosystems, including in mangrove forests. Effective use of this technique requires understanding of the spatial variability in δ13C among primary producer(s) as well as quantification of the isotopic fractionations that occur as C moves within and among ecosystem components. In this experiment, we assessed δ13C variation in the cosmopolitan mangrove Avicennia marina across four sites of varying physico-chemical conditions across two estuaries. We also compared the isotopic values of five distinct tissue types (leaves, woody stems, cable roots, pneumatophores and fine roots) in individual plants. We found a significant site effect (F3, 36 = 15.78; P < 0.001) with mean leaf δ13C values 2.0‰ more depleted at the lowest salinity site compared to the other locations. There was a larger within-plant fractionation effect, however, with leaf samples (mean ± SE = −29.1 ± 0.2) more depleted in 13C than stem samples (−27.1 ± 0.1), while cable root (−25. 8 ± 0.1), pneumatophores (−25.7 ± 0.1) and fine roots (−26.0 ± 0.2) were more enriched in 13C relative to both aboveground tissue types (F4, 36 = 223.45; P < 0.001). The within-plant δ13C fractionation we report for A. marina is greater than that reported in most other ecosystems. This has implications for studies of estuarine carbon cycling. The consistent and large size of the fractionation from leaf to woody stem (∼2.0‰) and mostly consistent fractionation from leaf to root tissues (>3.0‰) means that it may now be possible to partition the individual contributions of various mangrove tissues to estuarine food webs. Similarly, the contributions of mangrove leaves, woody debris and belowground sources to blue carbon stocks might also be quantified. Above all, however, our results emphasize the importance of considering appropriate mangrove tissue types when using δ13C to trace carbon cycling in estuarine systems..© 2018 Elsevier Ltd
Carbon uptake in surface water food webs fed by paleogroundwater
(American Geophysical Union, 2019-04-05) Mazumder, D; Saintilan, N; Hollins, SE; Meredith, KT; Jacobsen, GE; Kobayashi, T; Wen, L
The use of 14C to elucidate sources of carbon within freshwater aquatic ecosystems is challenging the assumption that modern autochthonous carbon dominates energy flows. We measured the uptake of old carbon through several trophic levels of a wetland fed by groundwater of the Great Artesian Basin, Australia, the largest artesian basin in the world. Stable isotopes (δ13C and δ15N) and radiocarbon (14C) were used to quantify food chain links and connection between groundwater and surface water food webs. Our results suggest that old groundwater was the dominant carbon source even at the highest trophic levels, with predatory fish returning apparent carbon ages of up to 11 ka. Stable isotope analysis (δ13C and δ15N) identified trophic links between fish, aquatic insects, and algae with smaller contributions from particulate organic matter to the food webs. As natural mound springs and associated wetlands are the only source of reliable water during dry periods over vast areas of the western Great Artesian Basin, the result has potential implications for the interpretation of archaeological artefacts associated with indigenous passage within the interior. ©2019. ANSTO, Macquarie University, Commonwealth of Australia.
Changes to fish assemblages visiting estuarine wetlands following the closure of commercial fishing in Botany Bay, Australia
(Taylor & Francis, 2008-10) Saintilan, N; Mazumder, D; Cranney, K
A Before-After, Control-Impact sampling design was used to measure changes in fish assemblages in intertidal mangroves and saltmarsh prior to and following the closure of commercial fishing in the Botany Bay estuary, New South Wales, Australia. Of commercial species found as juveniles in the wetlands, there was a consistent pattern of decrease in numbers compared to the pre-closure surveys. Other small wetland fish (such as the Gobiidae) were also found to have decreased in numbers, with the exception of the Common Toadfish (Tetractenos hamiltoni Gray and Richardson, 1843) and the Glassfish (Ambassis jacksoniensis Macleay, 1881). Results suggest that the immediate response of an estuarine fishery to commercial fishing closure may be a predator-mediated decline in juvenile fish of both prey and predator species. © 2008 Taylor & Francis Ltd. Open Access
Changes to fish assemblages visiting estuarine wetlands following the closure of commercial fishing in Botany Bay, Australia
(Ingenta, 2006-04-19) Saintilan, N; Mazumder, D; Cranney, K
Data on commercial landings of fish and crustaceans are available for 52 estuaries in New South Wales. These same estuaries have been mapped with regards to the distribution of fish habitat, including mangrove, saltmarsh, and seagrass, along with a suite of geomorphic units. A multiple regression analysis demonstrated strong relationships between the area of mangrove and the catch of a number of commercially important species, including long-finned eel, and the mud crab Scylla serrata. © 2007 Rosenstiel School of Marine and Atmospheric Science
Combined use of stable isotope analysis and elemental profiling to determine provenance of black tiger prawns (Penaeus monodon)
(Elsevier, 2019-01-01) Gopi, K; Mazumder, D; Sammut, J; Saintilan, N; Crawford, J; Gadd, PS
Global demand for seafood is rising, with a commensurate increase in supply from farmed and wild-caught products. Determining seafood provenance is important to reduce food fraud, and food safety and biosecurity risks. DNA and fatty acid profiling cannot independently distinguish between farmed, wild-caught and geographic origins of seafood. This study applied stable isotope analysis (SIA) and X-ray fluorescence (XRF), using Itrax, to test their effectiveness as tools to distinguish the origin and production methods of black tiger prawns (Penaeus monodon) from a range of Asia-Pacific locations. Isotopic and elemental data (31 elements) were analysed using multivariate methods, linear discriminant analysis (LDA), and randomForest. LDA and randomForest had consistent results: XRF effectively distinguished the production method and geographic origin of P. monodon (up to 100% accuracy), while SIA had a lower accuracy (up to 95% accuracy). However, SIA and XRF are effective complementary methods for determining provenance of black tiger prawns. Crown Copyright © 2018 Published by Elsevier Ltd.
Comparisons of fish catches using fyke nets and buoyant pop nets in a vegetated shallow water saltmarsh flat at Towra Point, NSW
(Coast and Wetlands Society, 2005) Mazumder, D; Saintilan, N; Williams, RJ
The selection of appropriate sampling methods is a prerequisite for the design of any survey detailing nekton assemblages. In the present study two commonly used saltmarsh fish sampling methods, the fyke net and the buoyant pop net, were used to compare the assemblages of fish caught in a saltmarsh flat during monthly spring tides over a twelve month period. Both nets were made of 2mm mesh. A total of 3514 fish and crustaceans of 21 species were captured by 48 fyke net sets and 818 fish of 16 species were captured by 48 pop net releases. Fyke and pop nets recorded significantly different (ANOSIM: P<0.001) assemblages, with higher proportions of Pseudomugil signifer caught in the fyke nets and Ambassis jacksoniensis in the pop nets. Five species, Sillago cilliata, Rhabdosargus sarba, Redigobius macrostoma, Taeniodes mordax and Metapenaeus macleayi, were caught in the fyke nets only. Significant differences in the size of fish caught were recorded for two species, Gobiopterus semivestitus and Gerres subfasciatus, with larger fish on average caught in the pop nets. The result suggested that pop nets are less efficient at catching smaller fish. © The Authors, CC-BY-ND 3.0
Determining the provenance and authenticity of seafood: a review of current methodologies
(Elsevier B. V., 2019-09) Gopi, K; Mazumder, D; Sammut, J; Saintilan, N
Background: Globally, food provenance has become a concern for government authorities, the seafood industry and consumers due to increasing food safety and authenticity requirements. Wild-catch fisheries and aquaculture are both important industries; aquaculture is seen as an opportunity to strengthen food security for the growing global population. However, unregulated aquaculture can expose consumers to health risks from pathogens, antibiotics and banned chemicals. Consumers and retailers, and the reputation of the global seafood industry, is affected by food fraud through species substitution and the exchange of aquaculture produce with wild-caught product and vice versa. To ensure consumer confidence and to allow authorities to effectively enforce regulations and contain risks, methods to determine the species, production methods and geographic origin of seafood need to be readily available. Scope and approach This review summarises the currently available and emerging methodologies to determine the provenance and authenticity of seafood. The main focus of this review is to give an overview of the methods that could potentially be used by authorities to enforce regulations and to contain risks, and for the seafood industry to self-regulate and protect itself from food fraud. Key findings and conclusions The most common methods used are DNA profiling, fatty acid profiling, different methods of inductively coupled plasma spectrometry and stable isotope analysis. Additionally, methods such as blockchain, radio frequency identification and x-ray fluorescence through Itrax are currently being tested for their effectiveness in determining seafood provenance. However, these methods have drawbacks and it is likely that a combination of methods would be best suited to determine the provenance of seafood considering its complex supply chain. Crown Copyright © 2019 Published by Elsevier Ltd.
Developing a MySQL database for the provenance of black tiger prawns (Penaeus monodon)
(MDPI, 2023-07-11) Gopi, K; Mazumder, D; Crawford, J; Gadd, PS; Tadros, CV; Atanacio, AJ; Saintilan, N; Sammut, J
As the demand for seafood increases, so does the incidence of seafood fraud. Confirming provenance of seafood is important to combat fraudulent labelling but requires a database that contains the isotopic and elemental “fingerprints” of authentic seafood samples. Local isotopic and elemental databases can be scaled up or combined with other databases to increase the spatial and species coverage to create a larger database. This study showcases the use of isotopic and elemental fingerprints of the black tiger prawn (Penaeus monodon) to develop a database that can be used to securely store the data necessary for determining provenance. The utility of this database was tested through querying and building seven different datasets that were used to develop models to determine the provenance of P. monodon. The models built using the data retrieved from the database demonstrated that the provenance of P. monodon could be determined with >80% accuracy. As the database was developed using MySQL, it can be scaled up to include additional regions, species, or methodologies depending on the needs of the users. Combining the database with methods of determining provenance will provide regulatory bodies and the seafood industry with another provenance tool to combat fraudulent seafood labelling. © 2023 The Authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/4.0/)
Distinguishing between farmed and wild-caught black tiger prawns, Penaeus monodon, using stable isotopes
(MedCrave Group, 2018-01-09) Gopi, K; Mazumder, D; Saintilan, N; Sammut, J
Determining farmed from wild-caught seafood is important to alleviate public health concerns associated with food safety as well as combatting food fraud. This study applied stable isotope analysis (SIA) to determine provenance of farmed and wild-caught black tiger prawns, P. monodon. Isotopic analysis showed that wild P. monodon were significantly enriched in δ13C (p<0.0001) compared to those that were farmed. The results of this case study suggest SIA can be used effectively to differentiate between farmed and wild-caught black tiger prawns, and potentially to determine the production method for other seafood commodities. ©2018 Gopi, et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and build upon your work non-commercially.
Effect of acidification on elemental and isotopic compositions of sediment organic matter and macro-invertebrate muscle tissues in food web research
(Wiley-Blackwell, 2010-10-30) Mazumder, D; Iles, J; Kelleway, JJ; Kobayashi, T; Knowles, L; Saintilan, N; Hollins, SE
Stable isotope techniques in food web studies often focus on organic carbon in food sources which are subsequently assimilated in the tissue of consumer organisms through diet. The presence of non-dietary carbonates in bulk samples can affect their δ13C values, altering how their results are interpreted. Acidification of samples is a common practice to eliminate any inorganic carbon present prior to analysis. We examined the effects of pre-analysis acidification on two size fractions of sediment organic matter (SOM) from marine and freshwater wetlands and pure muscle tissue of a common freshwater invertebrate (Cherax destructor). The elemental content and isotopic ratios of carbon and nitrogen were compared between paired samples of acidified and control treatments. Our results showed that acidification does not affect the elemental or isotopic values of freshwater SOM. In the marine environment acidification depleted the δ13C and δ15N values of the fine fraction of saltmarsh and δ15N values of mangrove fine SOM. Whilst acidification did not change the elemental content of invertebrate muscle tissue, the δ13C and δ15N values were affected. We recommend to researchers considering using acidification techniques on material prepared for stable isotope analysis that a formal assessment of the effect of acidification on their particular sample type should be undertaken. Further detailed investigation to understand the impact of acidification on elemental and isotopic values of organic matter and muscular tissues is required. © 2010, Wiley-Blackwell. The definitive version is available at www3.interscience.wiley.com
Environmental flow water and aquatic consumer food web structure: temporal aspects
(NSW Department of Environment, Climate Change and Water, and the CSIRO Water for a Healthy Country Flagship, 2010-05-11) Iles, J; Kobayashi, T; Knowles, L; Saintilan, N; Mazumder, D
We examined the structure of a consumer food web in a swamp on the Lowbidgee floodplain which was inundated by an environmental flow for nine months. The food web structure was measured as a two-dimensional space (polygon) formed by mean δ13C and δ15N values of consumer species. The change in the food web structure was assessed by examining the shape and area of polygons. We found marked temporal changes in the consumer food web structure with the development of the swamp. The mean δ13C value of the consumer population decreased within the swamp indicating a consumer shift to a more 13C depleted food source. The amount of niche space occupied by the consumer population reduced although the nearest neighbour distance between species increased. We conclude that floodplain habitats such as inundated swamps in the Lowbidgee provide a broader range of food items to consumer species for relatively longer periods of time, enabling the food web structure to develop following an environmental flow.
Equivalence of trophic structure between a tropical and temperate mangrove ecosystem in the Indo-Pacific
(CSIRO Publishing, 2019-05-22) Mazumder, D; Saintilan, N; Yusoff, FM; Kelleway, JJ
In this study we compared ecosystem trophic structure between a tropical mangrove forest at Matang, Malaysia, and a temperate mangrove forest near mangrove poleward limits at Towra Point in south-east Australia. These forests are separated by 8500 km of ocean over 45° of latitude and are of contrasting size, productivity and diversity. However, we observed a marked degree of similarity in food chain length (approximately four trophic levels in both forests), the taxonomy of key intermediate members of the food chain and the isotope signature of primary carbon sources, suggesting a strong contribution of surface organic matter rather than mangrove detritus. Common families were represented among dominant grazing herbivores, zooplanktivorous fishes, decapod crustaceans and top predators. These similarities suggest that there is some consistency in trophic interactions within two mangroves on opposite sides of the Indo-Pacific, despite a degree of evolutionary divergence in the assemblage. © CSIRO 2019
Evaluating trophic linkages in mangrove-based food webs using stable isotopes of carbon and nitrogen
(Ingenta, 2006-04-19) Mazumder, D; Szymczak, R; Saintilan, N; Williams, RJ
An understanding of the energy flow pathways and trophic linkages in estuarine food webs is essential for managing estuaries and their ecosystems sustainably. These pathways are complex, given the dynamics in physico-chemical processes, variety and area of habitats. Carbon and nitrogen stable isotope ratios (δ13C and δ15N) were measured for a variety of fish, invertebrate, and crustacean species collected from saltmarsh and mangrove habitats in Botany Bay and Homebush Bay, NSW, Australia. The work is on-going, however, initial observations indicate specific prey-predator linkages evident within a complex trophic structure. Results also advocate the role of certain non-commercial estuarine species as important conduits of energy and nutrition to higher trophic order commercially valuable species, linking these with specific estuarine habitats. This work seeks to model the source of energy and nutrition in mangrove and saltmarsh-based food webs and to determine the chemical linkages between high trophic order species and different habitat resources. © 2007 Rosenstiel School of Marine and Atmospheric Science
Evaluating trophic linkages in mangrove-based food webs using stable isotopes of carbon and nitrogen
(Rosenstiel School of Marine and Atmospheric Science University of Miami, 2006-04-19) Mazumder, D; Szymczak, R; Saintilan, N; Williams, RJ
An understanding of the energy flow pathways and trophic linkages in estuarine food webs is essential for managing estuaries and their ecosystems sustainably. These pathways are complex, given the dynamics in physico-chemical processes, variety and area of habitats. Carbon and nitrogen stable isotope ratios (δ13C and δ15N) were measured for a variety of fish, invertebrate, and crustacean species collected from saltmarsh and mangrove habitats in Botany Bay and Homebush Bay, NSW, Australia. The work is on-going, however, initial observations indicate specific prey-predator linkages evident within a complex trophic structure. Results also advocate the role of certain non-commercial estuarine species as important conduits of energy and nutrition to higher trophic-order commercially valuable species, linking these with specific estuarine habitats. This work seeks to model the source of energy and nutrition in mangrove and saltmarsh-based food webs and to determine the chemical linkages between high trophic order species and different habitat resources. © The Authors.
Facing the challenges of food fraud in the global food system
(Academic Press, 2021) Sammut, J; Gopi, K; Saintilan, N; Mazumder, D
Food fraud is an economically motivated act of deception which can impact consumers and the reputation of actors along a food supply chain. Food fraud includes adulteration, substitution, mislabeling, and other actions that might reduce the quality of food, deceive consumers, and other actors in the food supply chain, while increasing financial gains for the perpetrators. These actions can harm human health, thus raising food safety concerns, as demonstrated by outbreaks of disease caused by the adulteration of food. Food fraud occurs within global and national food systems and with a complex of intersecting food supply chains and networks, food fraud is increasingly challenging to combat. Many governments now have food monitoring programs, food safety strategies, and legal instruments to minimize opportunities for food fraud. This chapter provides an overview of common acts of food fraud and discusses some of their implications. Case studies on the adulteration of infant milk powder and horse meat substitution are used to describe how acts of food fraud can be perpetuated, how technology played a role in identifying the fraud, and how governments and the public responded. The technological advances and emerging analytical methods that are critically important to face the evolving challenges of food fraud are outlined. Specifically this chapter discusses emerging technologies, advantages and limitations of DNA, fatty acid, and elemental profiling, and stable isotope analysis used as analytical tools for detecting food fraud and determining the provenance of food. © 2021 Elsevier Inc.
Factors contributing to the iso-elemental fingerprinting of giant tiger prawns (Penaeus monodon)
(Australian Nuclear Science and Technology Organisation, 2019-09-03) Gopi, K; Mazumder, D; Sammut, J; Saintilan, N; Crawford, J; Gadd, PS
Demand for seafood has steadily increased as demonstrated by the growth in aquaculture production. By contrast, wild fisheries (i.e. wild-caught) production has plateaued. However, wild-caught and farmed seafood products are often sold alongside each other. Allowing for the substitution of higher value seafood products with those of lesser quality and value to occur. There are also reported cases involving human health risks associated with pathogens and banned substances present in fraudulently-marketed imported seafood. Accurate and reliable methods of seafood provenance are necessary to protect human health, improve biosecurity and maintain consumer confidence in seafood. Several methods are currently used for seafood provenance; however, there are drawbacks associated with some of these methods. A pilot study was conducted to scope the utility of isotopic and nuclear techniques to determine seafood provenance. Stable isotope analysis (SIA) and x-ray fluorescence (XRF) through Itrax were used to determine the isotopic and elemental fingerprint of giant tiger prawns (Penaeus monodon), a species that is traded globally. These fingerprints where then used to create a seafood provenance model based on multiple statistical methods. The pilot study showed that these methods could determine the provenance of seafood with over 80% accuracy. To further improve the accuracy of the models, the factors causing the isotopic and elemental variability, in the seafood products, need to be understood. Quantifying these factors will help develop more robust and reliable models. The current seafood provenance model development research examined the role of feed, water and sediment to the overall isotopic and elemental fingerprint of P. monodon. Replicate feed, water, sediment and P. monodon samples (n=9) were collected from nine different ponds in four farms around Queensland and New South Wales, Australia. These samples were then processed and analysed using SIA and XRF through Itrax to determine the isotopic and elemental composition of each individual sample. The results were then analysed using mixing models to quantify the isotopic and elemental flow from different feed and environmental components to the prawns. The analysis found that the feed and water are the major factors controlling the isotopic and elemental composition of P. monodon. Findings of these analyses will contribute to developing a scientifically robust and accurate model that can determine the provenance of seafood. This will allow for regulatory bodies to bolster consumer confidence, protect human health and allow for quarantining of seafood that could threaten local biodiversity and fisheries and aquaculture industries.
Feeding habits of five dominant fish species from Matang Mangrove Estuaries, Malaysia based on stomach contents and stable isotope analyses
(Research Square, 2021-05-14) Azim, MKM; Amin, SMN; Mazumder, D; Arshad, A; Yusoff, FM; Saintilan, N
The centres of mangrove biodiversity and productivity have been under-represented in studies of fish diet and habitat utilization, particularly in relation to environmental changes between wet and dry seasons. Feeding habits of five dominant fish species (Thryssa kammalensis, Ambassis gymnocephalus, Escualosa thoracata, Stolephorus baganensis and Johnius belangerii) were investigated from two sites in the Matang Mangrove ecosystem, Perak Malaysia, with sampling encompassing both wet and dry seasons. The stomach fullness of the fish was on average significantly higher in the wet season (48%) than in the dry season (32%) with isopods and copepods forming a more important component of the fish diet during the wet season than the dry season. The stomach contents of each species were, on average: T. kammalensis {(Animal based (A) = 50.11%, Plant based (P) = 38.24%)}, A. gymnocephalus (A = 50.35%, P = 37.99%), E. thoracata (A = 42.09%, P = 44.4%), S. baganensis (A = 38.17%, P = 46.55%) and J. belangerri (A = 25.35%, P = 58.86%). Therefore, all five fish species can be considered omnivorous. The similarity among diets varied from 60-80% during the wet and dry season. During the dry season, stable carbon and nitrogen isotope values of the samples had less variation, indicating narrow dietary sources compared to the wet season where the distribution of their isotopic values was larger. Seasons should be considered for planning mangrove management, as results of this study found contracted trophic breadth for commercially valuable fish in the dry season. This work is licensed under a CC BY 4.0 License.

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