Algal Farms Research Articles

Benthic Algal Assemblages Associated with Damselfi sh Territories in The Gulf of Thailand

Territorial damselfi sh are herbivorous fi sh that help maintain algal diversity and abundance by aggressive territorial defense and algal farming. We investigated the effect of territorial damselfi sh on algal diversity and abundance on a reef at Ko Taen, Surat Thani Province, Thailand. Ten permanent patches (20 × 20 cm2) were set up inside and ten outside damselfi sh territory and monitored bimonthly. We found 22 macroalgal species with fi ve dominant species: Polysiphonia sp., Padina minor, Ulva compressa, Gelidium pusillum, and Lobophora variegata. The abundance of Polysiphonia sp. was signifi cantly higher inside damselfi sh territory than outside. In contrast, the abundances of Gelidium pusillum, Padina minor, and Ulva compressa were slightly higher outside the territory. It might be perhaps because their feeding behavior, territorial defense, and farming activities altered the benthic community. These damselfi shes exclude other herbivorous fi shes from their territories and remove unpalatable algae and maintain their algal food crop. For species diversity, there was no signifi cant difference between algal species diversity outside and inside damselfi sh territories. Our results indicated that damselfi shes have a strong effect on algal abundance and composition.

Analysis of yield and types of carrageenan from different strains at Kupang Bay seaweed production center, East Nusa Tenggara

Kappaphycus alvarezzi is a species widely cultivated by the seaweed farmers surrounding Kupang Bay since the early 2000s. K. alvarezzi is sold as raw materials for the carrageenan industry as its hydrocolloid properties are used as emulsion and suspension stabilizers in the food and pharmaceutical industries. This study determines the yield and identifies the type of carrageenan from algal farms at Kupang Bay. Samples are collected from five production centers, then extracted at the Wet Laboratory at the Undana Faculty of Animal Husbandry, Marine and Fisheries in Kupang; and the extracted carrageenan is then analyzed using infrared spectroscopy at the Laboratory of the Faculty of Advanced and Multidisciplinary Technology Universitas Airlangga in Surabaya. The results showed that the highest yield of carrageenan was seaweed from Sulamu (25.72%) then, followed by Oenaek (19.6%), Tablolong A (13.48%), South Semau (11%), and Tablolong B as the lowest yield (9.6% ). Both the presence of functional groups such as D-galactose-4-sulphate and 3,6 anhydro D-galactose groups and the absence of D-galactose-2-sulfate and the 3,6 anhydrogalactose-2-sulfate group, concluded that the type of carrageenan produced in Kupang Bay is the kappa carrageenan.

High cell density culture of Neochloris oleoabundans in novel horizontal thin-layer algal reactor: Effects of localized aeration, nitrate concentration and mixing frequency

A horizontal thin-layer algal reactor was designed, constructed and tested for high cell density culture of an oil-rich green alga, Neochloris oleoabundans, at a thickness of 6 mm. A hollow fiber membrane sparger was used for localized aeration with CO2-enriched air, which allowed control of culture pH at a narrow range of pH 7.0–7.5. The optimal nitrate concentration under the investigated conditions was 345 mg-N/L with a cell density of ∼6.6 × 108 cells/mL and biomass concentration of ∼8 g/L. The volumetric and areal biomass productivities were 1.81 g/L/day and 10.85 g m− 2/day, respectively, and the maximum volumetric and areal productivities 3.57 g/L/day and 21.42 g m− 2/day, respectively. Intermittent mixing at a frequency of once every two hours (five min mixing each time) produced a cell growth profile similar to that of continuous mixing. Such intermittent mixing resulted in 98.38 % saving on mixing energy and 33.9 % reduction in water evaporation. It was observed that metabolic stress such as high pH and high nitrate concentration could inhibit cell division while causing cell size to enlarge abnormally. The results indicate that it is technically feasible to have high cell density culture of photoautotrophic microalgae with intermittent mixing and no culture circulation, opening the door towards the development of open algal farming systems of low capital, operational, and maintenance costs.

The economic feasibility of microalga to produce commercial biodiesel and reduce carbon dioxide emissions in Malaysia

Malaysia signed the Paris Agreement and agreed to lower its greenhouse gas (GHG) emissions by finding sustainable, renewable energy sources. One potential candidate is biodiesel made from the microalga, Chlorella vulgaris. Accordingly, this paper examines the economic feasibility of Malaysian agriculture to supply algal biodiesel and mitigate GHG emissions in Malaysia. The Malaysian Agriculture and Plantation Greenhouse Gas Model are employed for this purpose. The model contains the major agricultural commodities of Malaysia and forecasts market prices and quantities between 2024 and 2064. The simulation results indicate that the algal farms must sell algal biodiesel for a minimum price of USD0.66 per liter. The Malaysian government would pay a subsidy of USD0.14 per liter. The algal farms could supply 227.72 million liters in 2024 which grows to 277.37 million liters by 2064. The algal farms also dry the leftover slurry and sell it to the animal feed markets. The dried slurry contains protein and would help Malaysia reduce animal feed imports. Furthermore, Malaysia also produces biodiesel from palm oil and yellow grease. The algal, palm, and yellow grease biodiesel could reduce diesel tailpipe emissions by 0.11 million metric tonnes in 2024, which grows to 0.25 million tonnes by 2064. In addition, alga consumes the flue gas from coal and electric power plants and further reduces CO2 emissions by 1.06 million tonnes in 2024, which grows to 1.29 million tonnes in 2064. At last, an expanding biodiesel industry raises agricultural prices slightly and boosts agricultural employment.

Could technological improvements make microalgal biodiesel more economically feasible?

The economic feasibility and technological improvement to produce biodiesel from microalga, Chlorella vulgaris is investigated. The biodiesel would help Malaysia replace diesel with renewable and sustainable energy in the transportation sector. Accordingly, the Malaysian Agriculture and Plantation Greenhouse Gas Model is modified and extended to incorporate algal farms. The model forecasts Malaysia’s market prices and quantities of major agricultural commodities between 2024 and 2064. The state of the art is a commercial algal biodiesel industry is incorporated into a price endogenous model of Malaysia’s agriculture, and algal farms can experience technological improvement. The simulation results indicate that algal biodiesel is not economically feasible. The biodiesel price must be RM2.80 per litre or higher for the algal farms to produce biodiesel. The biodiesel price could be lowered to RM0.60 per litre if the algal farms experience a one-percent annual boost in either algal harvest yield or productivity gain. The results indicate that harvest yield improvements boost biodiesel production more than productivity improvements. The feasibility depends on algal farms to process the leftover slurry and supply the domestic animal feed markets. At last, the biodiesel offsets CO2 transportation sector emissions while the alga recycles the CO2 from fossil fuel electric power plants, which help Malaysia sequester high levels of CO2.

Blue green algal farming revolution: An eco-friendly top-up step for Agribusiness advancements

Global population growth rate accelerating earth ecosystem disturbance and increasing resource scarcity, malnutrition and poverty. These events challenge socio-economic development of each country and obligate scientific communities to develop such novel approaches to overcome this burden, which not only provide a healthy diet but also engage people in setting up their own business. Therefore, microalgae Spirulina is the one of the emerging food source with rich protein content and other nutritional components in adequate amount with diverse health benefits. The small scale investments in microalgae biomass production, familiarizing nutraceutical values and convert in consumable forms is the interesting agribusiness with diversified profits and popularization. Spirulina production strategies can be conventional and low-cost effective technologies. These techniques also help in designing new innovative possibilities in modifications and enhancements in the existing agriculture products processing strategies for their better use in different industries. Although most of communities are aware about agribusiness strategies of Spirulina but still it is in one the demanding and upcoming bright sector. This article reveals the methods of mass production of Spirulina and their significant role in agriculture as well as industrial.

Economic feasibility and sustainability of commercial bioethanol from microalgal biomass: The case of Malaysia

Malaysia fosters its economic growth with fossil fuels, which are not sustainable and raise atmospheric carbon dioxide. This study aims to assess the economic feasibility and sustainability of Chlorella vulgaris to create bioethanol for the transportation sector. A partial equilibrium model of the Malaysian agricultural markets is modified to include algal farms. The model forecasts agricultural prices, quantities, employment, fertiliser usage, and greenhouse gas emissions. The results suggest the algal farms produce 47.38 million litres of bioethanol in 2024 and peak at 163.67 million litres in 2044 for $0.65 per litre. This bioethanol offsets 0.11 million metric tons of carbon dioxide equivalent emissions from the transportation sector in 2024, which grows to 0.37 million tons in 2044. The microalga consumes the flue gas of coal and natural gas electric power plants – 0.31 million metric tons of carbon dioxide in 2024 and 1.09 million tons in 2044. The algal farms also sell dried slurry to the animal feed markets, which offsets the algal farm's high costs. The algal farms slightly raise Malaysia's agricultural commodity and fertiliser prices while boosting agricultural employment. The Malaysian government should subsidise algal bioethanol at $0.12 per litre.

Estimating the potential of algal biodiesel to improve the environment and mitigate palm oil mill effluents in Malaysia

Although Malaysia produces palm biodiesel to boost renewable energy, the palm oil mills produce large quantities of palm oil mill effluent (POME), which emit methane, a potent greenhouse gas. Microalga could consume the POME and supply lipids for biodiesel. To investigate the economic feasibility of biodiesel made from microalgae, this study employs a partial equilibrium model of Malaysia's agricultural sector. The analysis hinges on the base scenario, whereas the algal farms use regular water, labour, fertiliser, and CO2 from electric power plants as production inputs. For the second scenario, algal farms could blend POME into the algal ponds. Results indicate that algal farms' operating and capital costs are high, and they do not produce biodiesel until the biodiesel price reaches RM3.25 (or $US 0.78)/litre. The algal farms start producing 425.9 ML of algal biodiesel in 2024 that attain a peak in 2039 and starts declining. The alga farms using POME reduce their fertiliser costs; the algal farms increase biodiesel production slightly as algal farms utilise a fourth of the POME. Another interesting aspect of this research is algal biodiesel reduces greenhouse gases considerably by reducing tailpipe emissions from diesel engines, methane emissions by utilising POME, and CO2 emissions from coal and natural gas electric power plants. Other countries, such as Indonesia and Thailand, could also benefit from this analysis and clean up their palm oil industry since they share a similar tropical climate.

Nutrient Enrichment Predominantly Affects Low Diversity Microbiomes in a Marine Trophic Symbiosis between Algal Farming Fish and Corals

While studies show that nutrient pollution shifts reef trophic interactions between fish, macroalgae, and corals, we know less about how the microbiomes associated with these organisms react to such disturbances. To investigate how microbiome dynamics are affected during nutrient pollution, we exposed replicate Porites lobata corals colonized by the fish Stegastes nigricans, which farm an algal matrix on the coral, to a pulse of nutrient enrichment over a two-month period and examined the microbiome of each partner using 16S amplicon analysis. We found 51 amplicon sequence variants (ASVs) shared among the three hosts. Coral microbiomes had the lowest diversity with over 98% of the microbiome dominated by a single genus, Endozoicomonas. Fish and algal matrix microbiomes were ~20 to 70× more diverse and had higher evenness compared to the corals. The addition of nutrients significantly increased species richness and community variability between samples of coral microbiomes but not the fish or algal matrix microbiomes, demonstrating that coral microbiomes are less resistant to nutrient pollution than their trophic partners. Furthermore, the 51 common ASVs within the 3 hosts indicate microbes that may be shared or transmitted between these closely associated organisms, including Vibrionaceae bacteria, many of which can be pathogenic to corals.

Long term relationship between farming damselfish, predators, competitors and benthic habitat on coral reefs of Moorea Island

Understanding the processes that shape biodiversity is essential for effective environmental management. Across the world’s coral reefs, algal farming damselfish (Stegastes sp.) modify the surrounding benthic community through their creation of algae “farms”. Using a long-term monitoring dataset (2005–2019) from Moorea Island, French Polynesia, we investigated whether the density of dusky damselfish (Stegastes nigricans) is associated with benthic habitat composition, the density of predators and/or competitors, and whether the survey area was inside or outside of a Marine Protected Area (MPA). We found no evidence that benthic cover or number of competitors were associated with dusky damselfish densities, both inside and outside MPAs. In contrast, fluctuations in dusky damselfish densities were negatively associated with the density of predators (e.g. Serranidae, Muraenidae and Scorpaenidae) in the preceding year in non-MPA areas, and both within and outside of MPAs when predator densities were high (2005–2010). These results suggest that healthy predator populations may be important for regulating the abundances of keystone species, such as algal farming damselfish, especially when predator densities are high.

Herbivorous damselfishes expand their territories after causing white scars on Porites corals

Turf algae become the most abundant benthic group on coral reefs after mass coral bleaching. By defending feeding territories, damselfishes enhance the growth of turf algae in so-called algal farms and affect coral communities both directly and indirectly. We found several white scars (i.e., bite lesions) on massive Porites colonies around feeding territories. In this study, we examined the occurrence of white scars on corals and their function in coral–algal competition at the boundaries between algal farms of two damselfish species—the intensive farmer Stegastes nigricans, and the intermediate farmer S. lividus—and adjacent Porites corals for 3 years around Okinawa Island, Japan. White scars occurred on Porites colonies only adjacent to the territories of both damselfish species. Of the white scars on corals around S. nigricans territories, 73% of the area was covered by algae within 2 weeks, while the remaining was re-covered by Porites tissues. The coral–algal boundaries encroached further into areas of coral when the area of white scars were larger. These results suggest that both intensive and intermediate farmers bite adjacent Porites colonies causing white scars on corals, and expand their territories onto corals using algae-covered white scars as stepping stones.

Feasibility of farming the agarose-yielding red alga Gracilaria dura using tube-net cultivation in the open sea along the Gujarat coast of NW India

ABSTRACT Despite some perceptions of economic risk, the global aquaculture industry continues to attract new entrepreneurs and investors. However, to sustain this trend, innovative and cost-effective strategies are needed. In recent years, algal farming has been shown to be a sustainable activity in the global Blue Economy. In 2015, harvests of the red algal agarophyte genus Gracilaria surged to over 114,100 tons dry weight which constituted ca. 91% of the total raw material for industrial agar production. We carried out a trial of experimental farming of the agar-yielding alga known as Gracilaria dura using a tube-net method along the Gujarat coast, India. The mean daily growth rate (DGR) of this agarophyte ranged from 1.88 ± 0.23% day−1 to 3.30 ± 0.25% day−1. Similarly, the mean yield varied between 0.62 ± 0.03 kg and 1.05 ± 0.02 kg fresh wt m−1 of tube-net. A Pearson correlation showed that both DGR and biomass yield were positively correlated with temperature. In addition, the DGR was significantly positively correlated with air temperature (r = 0.916; p < 0.01) whereas biomass yield was also positively correlated with surface seawater temperature (r = 0.986; p < 0.001). The economic projections for four harvests per year revealed that the value of the product was US$5577, while the investment required for the necessary tube-net infrastructure was US$1797 thereby providing US$1890 as profit to single farmers, a significant amount in the coastal communities of Gujarat. Thus, undertaking commercial farming of G. dura in Indian waters could diversify the livelihood of artisanal, coastal fishermen and further encourage the indigenous production of agarose.

Intruder identity alters the response of territorial damselfish protecting algal farms

Herbivorous damselfish that cultivate algal farms frequently exhibit aggressive territorial behaviour to defend their investment from intruders, particularly against other herbivorous fish and invertebrates. On a coastal coral reef in New Caledonia, the response of the damselfish Hemiglyphidodon plagiometopon to intruders of varying type and level of threat to their algal farm was tested. Responses to live and dead coral fragments, carnivorous whelks, shells, and rocks varied from no response to biting and extrusion from farms. Damselfish elicited the strongest defensive response to the herbivorous sea urchin Echinometra mathaei, rapidly attacking the urchin by biting and lifting it from farms, before extruding it up to 3.5 m away. H. plagiometopon responded in a similar manner to dead urchins (no threat of herbivory) as to live urchins, but typically did not extrude them as far. Ultimately, damselfish responded to intruders in a manner largely consistent with the level of threat posed to their algal farm, with the similar response between live and dead urchins suggesting such strong defensive behaviours may be combination of ‘hard-wired’ and learned behaviours in reaction to the level of realised threat.

Development of phycology in Malaysia

Phycological research in Malaysia started in the 1900s with the documentation of both freshwater and marine microalgae and seaweeds, especially those with economic importance. Phycological research has grown and matured from initial diversity and ecological studies to DNA-based research which allowed us to venture into the world of algal biotechnology with focus on phylogenetics, genomics and strain improvement. Our research has expanded towards finding solutions to the declining food and fuel resources to be relevant in today’s world of energy and food crises amidst a changing climate. Sustainability solutions are especially relevant and will continue to drive the development of our seaweed industry and the opportunities for establishment of an algal industry in Malaysia. Algal farming offers many opportunities for research and development activities, and great potential, especially due to the abundant tropical sunshine, long coastline, good infrastructure and global connectivities. This paper is a brief account of the development of phycology in Malaysia, followed by some thoughts on future directions. Our research is supported by two very important collections: (i) the University of Malaya Algae Culture Collection (UMMAC) and (ii) the University of Malaya Seaweeds and Seagrasses Herbarium.

The Montara Oil Spill: A 2009 Well Blowout in the Timor Sea

A well on the Montara platform on the Australian continental shelf blew out in August 2009 and spilled oil into the Timor Sea for 74days. The oil, estimated at as much as 23.5 million L in total volume, spread over a large area of the shelf and eventually into Indonesian waters. This paper documents, through published literature, reports of both Australian and Indonesian governments and observations of coastal residents and fishermen the spread of the oil and attempts to estimate its impact. The lack of observers on the ocean and baseline, pre-spill data on populations of marine organisms, and delays in deploying scientific surveys after the spill severely limited efforts by the Australian government to determine damage in its territorial waters. Biological survey work was not done in Indonesian waters, but coastal residents attested to relatively severe impacts to algal farms. In addition fish landings declined in one port in southwest Timor Island.

Local variations in microhabitat use by Stegastes fuscus (Cuvier, 1830) (Teleostei: Pomacentridae) in a tropical reef of Brazil

Due to their widespread abundance and territorial habits, damselfishes play central roles in reefs worldwide, but the extent to which they modify the reef's substrate varies both amongst and within species. The present study evaluated microhabitat preferences and the role of the common damselfish Stegastes fuscus (Cuvier, 1830) (Teleostei: Pomacentridae) as a benthic community modifier in a tropical algal-dominated reef. We employed video survey techniques to assess fish density and microhabitat use and, additionally, the biomass of sessile components were compared inside and immediately outside algal farms of S. fuscus. Individuals showed pronounced microhabitat preference, but with prominent local (i.e. small-scale) variations in benthic cover. These local variations are reported for the first time and were due to individuals defending one of two contrasting microhabitats (i.e. turf-dominated or Palythoa caribaeorum-dominated). Further, significant differences in the biomass of sessile organisms were observed within algal farms suggesting that S. fuscus plays a keystone role in the benthic community of the reef. The implications of the prominent local variation in microhabitat use are discussed and strongly illustrate the behavioral plasticity of this damselfish.

Occupation Dynamics and Impacts of Damselfish Territoriality on Recovering Populations of the Threatened Staghorn Coral, Acropora cervicornis.

Large-scale coral reef restoration is needed to help recover structure and function of degraded coral reef ecosystems and mitigate continued coral declines. In situ coral propagation and reef restoration efforts have scaled up significantly in past decades, particularly for the threatened Caribbean staghorn coral, Acropora cervicornis, but little is known about the role that native competitors and predators, such as farming damselfishes, have on the success of restoration. Steep declines in A. cervicornis abundance may have concentrated the negative impacts of damselfish algal farming on a much lower number of coral prey/colonies, thus creating a significant threat to the persistence and recovery of depleted coral populations. This is the first study to document the prevalence of resident damselfishes and negative effects of algal lawns on A. cervicornis along the Florida Reef Tract (FRT). Impacts of damselfish lawns on A. cervicornis colonies were more prevalent (21.6% of colonies) than those of other sources of mortality (i.e., disease (1.6%), algal/sponge overgrowth (5.6%), and corallivore predation (7.9%)), and damselfish activities caused the highest levels of tissue mortality (34.6%) among all coral stressors evaluated. The probability of damselfish occupation increased as coral colony size and complexity increased and coral growth rates were significantly lower in colonies with damselfish lawns (15.4 vs. 29.6 cm per year). Reduced growth and mortality of existing A. cervicornis populations may have a significant effect on population dynamics by potentially reducing important genetic diversity and the reproductive potential of depleted populations. On a positive note, however, the presence of resident damselfishes decreased predation by other corallivores, such as Coralliophila and Hermodice, and may offset some negative impacts caused by algal farming. While most negative impacts of damselfishes identified in this study affected large individual colonies and <50% of the A. cervicornis population along the FRT, the remaining wild staghorn population, along with the rapidly increasing restored populations, continue to fulfill important functional roles on coral reefs by providing essential habitat and refuge to other reef organisms. Although the effects of damselfish predation are, and will continue to be, pervasive, successful restoration efforts and strategic coral transplantation designs may help overcome damselfish damage by rapidly increasing A. cervicornis cover and abundance while also providing important information to educate future conservation and management decisions.

Application of oligoagars as elicitors for field aquaculture of Pyropia haitanensis

Oligosaccharides can elicit a defense-related response in marine algae or seaweeds. This study aimed to investigate the possible application of oligosaccharides as biological elicitors for algal farming by measuring their antirotting effects on Pyropia haitanensis. The concentration of oligoagars and the time of treatment were optimized by examining their effects on the percentage of rotting in thalli. Oxidative burst and expression of defense-related genes were examined. The optimized conditions obtained were then applied in an aquaculture setting for P. haitanensis. Elicitation with oligoagars at 100 μg mL−1 for 2 h produced the optimal rot resistance effect, and oligoagars delayed the severe rotting of thalli by more than 13 days. Oligoagars elicited rapid respiration in thalli. The expression levels of Phrboh and Phhsp70 genes were up-regulated whereas Phsod was down-regulated. During aquaculture, treatment with oligoagars when thalli were 30 days old and when conchospores adhered to nets improved growth, increased yield of products, and delayed the maturation of thalli. However, treatment when conchospores adhered to nets had better results and was more convenient and practical. Overall, we found that oligoagars have potential applications as elicitors for biological farming and can be applied in the aquaculture of P. haitanensis with promising results.

Temperate territorial damselfish act like tropical damselfish, but have no measurable effect on algae within their feeding areas

Areas of high habitat heterogeneity support a high diversity of fauna in both terrestrial and aquatic systems. In altering the rate of consumption of benthic communities, tropical damselfish affect the rate and trajectory of succession, and maintain habitat heterogeneity. Such algal ‘farming’ behaviour is well documented for many tropical damselfish species in coral reef environments. Our study aimed to test the behavioural potential of the temperate water damselfish Parma mccullochi (McCulloch's scalyfin) to modify algal assemblages within their territories, and to assess the effect of any such behaviour on algal assemblages. We found that P. mccullochi behave in a similar way to tropical damselfish that maintain extensive algal farms: P. mccullochi feed over a large multispecies area, maintain a temporally consistent feeding rate (disturbance), and defend the territory against other herbivorous fish. However, we detected no change in the algal assemblage with the exclusion of resident fish from parts of their feeding areas. In contrast to many tropical damselfishes this feeding disturbance does not have any measurable short term effects on the algal composition of their feeding areas. Our study synthesises and builds upon the few published studies on temperate damselfish, all of which report no measurable change to the alga of the feeding area. However, we propose that disturbance by these species instead plays a longer term role in reducing the rate of re-colonisation of clearances within the algal canopy, and thus maintaining habitat heterogeneity on canopy dominated rocky reef.

Diet disparity among sympatric herbivorous cichlids in the same ecomorphs in Lake Tanganyika: amplicon pyrosequences on algal farms and stomach contents.

BackgroundLake Tanganyika, an ancient lake in the Great Rift Valley, is famous for the adaptive radiation of cichlids. Five tribes of the Cichlidae family have acquired herbivory, with five ecomorphs: grazers, browsers, scrapers, biters and scoopers. Sixteen species of the herbivorous cichlids coexist on a rocky littoral slope in the lake. Seven of them individually defend feeding territories against intruding herbivores to establish algal farms. We collected epiphyton from these territories at various depths and also gathered fish specimens. Algal and cyanobacteria community structures were analysed using the amplicon-metagenomic method.ResultsBased on 454-pyrosequencing of SSU rRNA gene sequences, we identified 300 phototrophic taxa, including 197 cyanobacteria, 57 bacillariophytes, and 31 chlorophytes. Algal farms differed significantly in their composition among cichlid species, even in the same ecomorph, due in part to their habitat-depth segregation. The algal species composition of the stomach contents and algal farms of each species differed, suggesting that cichlids selectively harvest their farms. The stomach contents were highly diverse, even between species in the same tribe, in the same feeding ecomorph.ConclusionsIn this study, the amplicon-metagenomic approach revealed food niche separation based on habitat-depth segregation among coexisting herbivorous cichlids in the same ecomorphs in Lake Tanganyika.Electronic supplementary materialThe online version of this article (doi:10.1186/s12915-014-0090-4) contains supplementary material, which is available to authorized users.