Citizens Of The Sea report: Tonga EEZ

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The CitSea Interactive Reports allow you to explore offshore biodiversity results from environmental DNA (eDNA) sampling. At the top of each site report, headline indicators summarise what was detected, including the number of kingdoms, ASVs (amplicon sequence variants), families, and species.

Use the navigation tabs to switch between different views:

Sampling Map shows where samples were collected;

Species Gallery provides a visual look at taxa detected;

Taxa Table lists results in a searchable format;

Diversity tab display richness and diversity indices;

AI-based Summary highlights key findings;

NIS and HABs tab flags non-indigenous species and species that have the potential to form harmful algal blooms; and

Marine Vertebrates tab highlights locations where marine vertebrates were detected.

Interactive maps let you zoom in on specific sites, and hovering over a marker reveals metadata for that location. Sample ID numbers can be input into the Taxa Table to explore taxa detected at specific locations. Each dataset is linked with metadata and reference databases to ensure transparency and scientific value.

Note on Contamination and Filtering:

Because eDNA is highly sensitive, sequences from terrestrial organisms (e.g., humans, land mammals, or laboratory contaminants) can sometimes appear in the results. Since CitSea samples are collected exclusively from seawater, any detections that were found in the negative controls, and those of clearly non-marine taxa have been carefully documented and then filtered out of the dataset before results are displayed. This ensures that the dashboard reflects only genuine marine biodiversity signals while maintaining transparency about data quality.

Glossary

ASV (Amplicon Sequence Variant)

An ASV is a unique DNA sequence identified from high-throughput sequencing of environmental samples. ASVs provide fine-scale resolution of biodiversity, capturing exact genetic variants rather than grouped clusters. The total number of ASVs reflects overall genetic diversity detected.

Kingdoms

The highest level of biological classification (e.g., animals, plants, fungi, protists, bacteria, archaea). Detecting multiple kingdoms shows the broad range of life captured in eDNA samples.

Families

A mid-level taxonomic category used to group related organisms (e.g., whales belong to the family Balaenopteridae). Counting families detected helps show how many different evolutionary lineages were present in the samples.

Species

The basic unit of biological classification. Species detection indicates specific organisms that can be identified from eDNA, though not all ASVs can be confidently resolved to species level.

Taxa

A general term for groups of organisms classified together at any rank in the biological hierarchy, such as species, families, or kingdoms. In the CitSea dashboard, “taxa” refers broadly to the different biological groups detected in eDNA samples.

HABs (Harmful Algal Blooms)

Certain algae can grow rapidly under favourable conditions, producing toxins or depleting oxygen in the water. These blooms can threaten marine ecosystems, fisheries, and human health. The dashboard highlights eDNA detections of ASVs that were taxonomically assigned to species known to cause HABs, reported in the IOC-UNESCO Taxonomic Reference List of Harmful Micro Algae (https://www.marinespecies.org/hab/).

NIS (Non-Indigenous Species)

Species that occur outside their natural range, often introduced by shipping, aquaculture, or other human activity. Some NIS can become invasive, outcompeting local species and disrupting ecosystems. The dashboard flags detections of known or potential NIS.

Kingdoms detected

7

Number of ASVs

9974

Families detected

379

Species detected

470

Map showing sampling locations as part of the 2024 Pacific Island Cruising Rally. Recreational sailors were equipped and trained to collect daily eDNA samples (in triplicate) during their offshore passages.

Map Tiles via Esri — National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, iPC.

We display every species we detected here, sorted by IUCN Red List status. The IUCN Red List Categories and Criteria are intended to be an easily and widely understood system for classifying species at high risk of global extinction. DD: Data deficient. LC: Least Concern. VU: Vulnerable. EN: Endangered. CR: Critically endangered.

Click on the image to open the relevant Atlas of Living Australia page.

From these samples we detected no species listed on the IUCN Red List as Critically Endangered, no as Endangered, no as Vulnerable, no as Near Threatened, one as Data Deficient, nine as Least Concern, and 370 species that have not yet been assessed by the IUCN.

IUCN Data Deficient species

Thunnus tonggol
Figure 1: Data Deficient species

IUCN Least Concern species

Hipposcarus longiceps

Kyphosus cinerascens

Kyphosus vaigiensis

Lethrinus obsoletus

Retropinna retropinna

Salmo trutta

Scomber scombrus

Thunnus albacares
Figure 2: Least Concern species

Not pictured: Encrasicholina punctifer.

Species not assessed by IUCN

Abylopsis tetragona

Aglaura hemistoma

Calocalanus pavo

Cerebratulus lacteus

Cerithium egenum

Cerithium rostratum

Cestum veneris

Cliona celata

Clypeomorus brevis

Creseis clava

Creseis virgula

Doliolum denticulatum

Haeckelia rubra

Liriope tetraphylla

Littorina littorea

Monetaria annulus

Oikopleura dioica

Ophiocoma echinata

Paracalanus parvus

Poecilochaetus serpens

Prostheceraeus vittatus

Protatlanta souleyeti

Sapphirina darwinii

Septifer bilocularis

Solmundella bitentaculata

Temora turbinata
Figure 3: Not Assessed species

Not pictured: Cosmocalanus darwinii, Alteromonas, Oithona similis, Miracia efferata, Macrosetella gracilis, Calocalanus curtus, Prochlorococcus MIT9313 marinus, Crocosphaera watsonii, Acartia negligens, Pseudoalteromonas, Halomonas, Clytia hummelincki, Algicola bacteriolytica, Trichodesmium IMS101 erythraeum, Photobacterium, Fabibacter misakiensis, Richelia HH01 intracellularis, Acrocalanus gracilis, Heliconoides inflatus, Staphylococcus, Clausocalanus furcatus, Nisaea nitritireducens, Penicillium rubens, Vibrio, Trichodesmium IMS101 havanum, Megalocercus huxleyi, Achromobacter, Corynebacterium accolens, Tenacibaculum litopenaei, Idiomarina, Pontella fera, Chloropicon sieburthii, Pseudoalteromonas phenolica, Lactococcus, Trichodesmium IMS101 thiebautii, Zoothamnium pelagicum, Spirotontonia grandis, Nanozoanthus harenaceus, Eutintinnus fraknoi, Temora discaudata, Vibrio fortis, Paracalanus indicus, Eutintinnus apertus, Phaeocystis globosa, Pseudomonas, Rhabdonella poculum, Micromonas pusilla, Abylopsis eschscholtzii, Calocalanus plumulosus, Paracalanus nanus, Apiospora arundinis, Undinula vulgaris, Ferosagitta robusta, Chloropicon laureae, Labrenzia marina, Climacocylis scalaroides, Euplotes nobilii, Moneuplotes minuta, Sinistrostrombidium cupiformum, Labrenzia alexandrii, Photobacterium angustum, Sapphirina opalina, Amphorellopsis quinquealata, Lensia campanella, Kocuria, Eutintinnus perminutus, Photobacterium leiognathi, Acrocalanus monachus, Sapphirina scarlata, Halomonas meridiana, Clausocalanus parapergens, Mecynocera clausi, Clausocalanus paululus, Euchaeta marina, Haloptilus longicornis, Paracalanus denudatus, Pontellina plumata, Clausocalanus arcuicornis, Subeucalanus subcrassus, Strombidinopsis acuminata, Clausocalanus jobei, Halomonas aquamarina, Shimia marina, Paracalanus tropicus, Oncaea waldemari, Cephalothrix filiformis, Clausocalanus pergens, Centropages violaceus, Pareucalanus attenuatus, Cobetia, Farranula gibbula, Mesonia mobilis, Grimontia indica, Pelagibius litoralis, Sphingomonas panni, Centropages furcatus, Alcanivorax venustensis, Paracalanus aculeatus, Sphaeronectes koellikeri, Eutintinnus medius, Vibrio caribbeanicus, Alteromonas genovensis, Psychrobacter, Pseudoscourfieldia marina, Cedecea neteri, Psychrobacter celer, Thalia democratica, Cutibacterium, Erythrobacter, Eucalanus pseudattenuatus, Vibrio azureus, Tenacibaculum, Marinobacter, Calocalanus minutus, Doliolum nationalis, Trichodesmium IMS101 contortum, Pleuromamma scutullata, Calocalanus styliremis, Ctenocalanus vanus, Psychrobacter piscatorii, Parallelostrombidium conicum, Chloropicon roscoffensis, Tropicibacter phthalicicus, Marinobacter manganoxydans, Thalassobius mediterraneus, Vibrio harveyi, Copilia mirabilis, Candacia simplex, Chloroparvula japonica, Candacia truncata, Pycnococcus provasolii, Lucicutia flavicornis, Brevundimonas, Shimia, Marinobacter hydrocarbonoclasticus, Streptococcus, Strombidium cf. basimorphum, Nanomia bijuga, Carnobacterium, Enhydrobacter aerosaccus, Pachos punctatum, Vibrio sagamiensis, Planktotalea frisia, Dermacoccus, Clostridium sensu stricto 1, Oncaea scottodicarloi, Gilvibacter sediminis, Pseudoalteromonas luteoviolacea, Pseudoalteromonas marina, Vampyrophrya pelagica, Paracalanus aff. denudatus PA0053.MED, Salpingacantha undata, Cyclotrichium cyclokaryon, Clausocalanus farrani, Firoloida desmarestia, Acrocalanus longicornis, Scolecithricella longispinosa, Oikopleura parva, Oikopleura fusiformis, Oncaea mediterranea, Sulfitobacter dubius, Maribacter, Polaribacter dokdonensis, Halomonas taeanensis, Alteromonas hispanica, Idiomarina baltica, Dokdonia genika, Salinicola salarius, Corynebacterium kroppenstedtii, Vibrio pomeroyi, Dolosigranulum pigrum, Chromohalobacter canadensis, Vibrio chagasii, Joostella marina, Chryseobacterium hominis, Dokdonia, Acinetobacter, Corynebacterium, Thalassotalea coralli, Salinicola, Oncaea media, Paracoccus oceanense, Photobacterium rosenbergii, Clausocalanus minor, Oithona attenuata, Chloropicon primus, Clytia gracilis, Alteromonas australica, Pantachogon haeckeli, Creseis conica, Emiliania huxleyi, Aidanosagitta regularis, Shewanella, Pinctada maculata, Rosacea flaccida, Hyalophysa lwoffi, Iridona iridescens, Idiomarina loihiensis, Gephyrocapsa oceanica, Oikopleura albicans, Euchaeta rimana, Pseudo-nitzschia multistriata, Chaetoceros rostratus, Phaeocystis cordata, Vibrio coralliilyticus, Ruegeria, Cycloclasticus, Syracosphaera pulchra, Epiplocyloides ralumensis, Grimontia, Alteromonas macleodii, Gephyrocapsa parvula, Canthocalanus pauper, Minutocellus polymorphus, Microbulbifer, Labrenzia, Canuella perplexa, Lentilitoribacter donghaensis, Stenosemella nivalis, Glossobalanus minutus, Vibrio ishigakensis, Aureitalea marina, Pseudo-nitzschia cuspidata, Malleus albus, Vibrio aestivus, Paraplanocera oligoglena, Notoplana australis, Oithona simplex, Vibrio nigripulchritudo, Persicobacter diffluens, Catinia plana, Paracalanus gracilis, Shewanella corallii, Chrysopetalum debile, Halomonas sulfidaeris, Romboutsia sedimentorum, Photobacterium damselae, Botryllus planus, Colwellia meonggei, Pseudopolydora paucibranchiata, Shewanella olleyana, Bolinopsis aff. vitrea SBJ-2021, Lactococcus piscium, Erwinia, Nonlabens, Herminiimonas, Leeuwenhoekiella, Pseudomonas pachastrellae, Pseudochrobactrum kiredjianiae, Flavobacterium johnsoniae, Vagococcus salmoninarum, Shewanella baltica, Marinomonas communis, Lactococcus raffinolactis, Janthinobacterium, Pseudoalteromonas ruthenica, Acinetobacter johnsonii, Oleibacter marinus, Sphingobacterium faecium, Thalassospira, Shewanella putrefaciens, Mesoflavibacter sabulilitoris, Flavobacterium tegetincola, Aeromonas, Muricauda, Oceanicaulis stylophorae, Pseudomonas lurida, Roseivirga spongicola, Bermanella marisrubri, Flavobacterium, Chaetoceros elegans, Chromohalobacter, Comamonas jiangduensis, Leuconostoc, Brochothrix thermosphacta, Penicillium citrinum, Sphingobacterium, Trichococcus, Psychrobacter fozii, Psychrobacter maritimus, Polyophthalmus pictus, Sulfitobacter, Sphingomonas, Rhodococcus, Terrisporobacter mayombei, Pseudochrobactrum, Aquimarina litoralis, Sphingobacterium nematocida, Moheibacter sediminis, Thalassotalea agarivorans, Thalassotalea loyana, Alcaligenes, Ruegeria profundi, Stenotrophomonas maltophilia, Marinobacterium stanieri, Wukongibacter baidiensis, Advenella, Agrobacterium, Sanguibacter, Vibrio diabolicus, Kaistia, Vibrio panuliri, Microbacterium, Flammeovirga aprica, Atelocyanobacterium (UCYN-A) thalassa, Armandia bilobata, Enterobacter, Bestiolina similis, Photobacterium aphoticum, Staphylococcus epidermidis, Ferrimonas marina, Braarudosphaera bigelowii, Raoultella planticola, Microbulbifer variabilis, Praxillella affinis, Vibrio alginolyticus, Psychrobacter marincola, Eunice notata, Microbulbifer agarilyticus, Aurospio foodbancsia, Serratia, Erwinia rhapontici, Rahnella aquatilis, Sphingobacterium tabacisoli, Raoultella, Candida metapsilosis, Ewingella americana, Clytia noliformis, Acinetobacter lwoffii, Granulicatella, Gari maculosa, Flammeovirga yaeyamensis, Paracoccus, Actinomyces, Owenia fusiformis, Micrococcus, Prymnesium polylepis, Brachybacterium, Tenacibaculum amylolyticum, Xystonella longicauda, Lynnella semiglobulosa, Euphausia vallentini, Gemella, Curtobacterium.

Images have been sourced from Wikimedia Commons.

We compare pieces of DNA sampled from the environment with a reference database. This table lists every species we detected, along with how closely the DNA we found matches known species in the reference database. For each species we list the IUCN Red List status. The IUCN Red List Categories and Criteria are intended to be an easily and widely understood system for classifying species at high risk of global extinction. DD: Data deficient. LC: Least Concern. VU: Vulnerable. EN: Endangered. CR: Critically endangered.

Table of detected taxa

Download CSV (zip)

Explore the types of organisms found in these samples. This interactive chart (Krona plot) lets you see which groups were most common — from broad categories like bacteria and animalia down to families and species of fishes. Click on individual segments to zoom in. :::

Krona Plot

Below are different diversity metrices plotted for all samples taken within this area. The first plot shows the relative abundance of different groups of organisms (classified at the class taxonomic level). The middle plot presents three commonly used measures of alpha diversity. These are different ways of describing how many unique ASVs were found in each sample. The bottom plot shows how similar or different samples are from one another. Each point represents a sample, and points there are close together have very similar species. For reference, the points are coloured based on the latitude where each sample was collected.

We asked an AI (Claude’s Anthropic 3.7) which species it thinks are the most interesting detected in this site, and why they are interesting. We reproduce the answer below. We ask Claude only for validated species, i.e., species that are known to occur in the area.

Trichodesmium species (IMS101 erythraeum, IMS101 havanum, IMS101 thiebautii, IMS101 contortum)

These marine cyanobacteria are among the ocean’s most important nitrogen fixers, converting atmospheric nitrogen gas into forms that other marine organisms can use. Often called “sea sawdust” because they form visible floating mats on the ocean surface, Trichodesmium plays a crucial role in ocean productivity by providing essential nutrients that support entire marine food webs. Their ability to fix nitrogen makes them particularly important in nutrient-poor tropical and subtropical waters, where they help sustain fish populations and coral reef ecosystems.

Prochlorococcus marinus MIT9313

This microscopic marine cyanobacterium is the most abundant photosynthetic organism on Earth and produces approximately 20% of the world’s oxygen. Despite being invisible to the naked eye, Prochlorococcus forms the foundation of ocean food webs and plays a vital role in regulating Earth’s climate by absorbing carbon dioxide during photosynthesis. Its discovery revolutionized our understanding of ocean ecology and highlighted the importance of microorganisms in maintaining the planet’s life-support systems.

Emiliania huxleyi

This single-celled marine algae is one of the most important calcifying organisms in the ocean, creating intricate calcium carbonate plates that form massive blooms visible from space. When these organisms die, their plates sink to the ocean floor, forming chalk deposits like the White Cliffs of Dover. Emiliania huxleyi plays a crucial role in the ocean’s carbon cycle and is considered a key indicator species for understanding how climate change affects marine ecosystems.

Thunnus tonggol (longtail tuna) and Thunnus albacares (yellowfin tuna)

These commercially valuable tuna species are prized for their high-quality meat and support billion-dollar fishing industries worldwide. Yellowfin tuna, recognizable by their bright yellow fins, can weigh up to 400 pounds and are essential for sushi and sashimi markets. Both species are important apex predators that help maintain ocean ecosystem balance, but face increasing pressure from overfishing and climate change.

Scomber scombrus (Atlantic mackerel)

This commercially important fish species supports major fisheries across the North Atlantic and provides an affordable source of protein rich in omega-3 fatty acids. Atlantic mackerel play a crucial ecological role as both predators of smaller fish and plankton, and as prey for larger marine animals including seabirds, marine mammals, and larger fish species.

Salmo trutta (brown trout)

Though primarily a freshwater species, sea-run brown trout spend part of their lives in marine environments and are highly valued by recreational anglers and commercial fisheries. These adaptable fish serve as important indicators of ecosystem health in both freshwater and coastal marine environments, with their populations reflecting the overall condition of watersheds and nearshore habitats.

Vibrio species (harveyi, coralliilyticus, chagasii, and others)

These marine bacteria include both beneficial and harmful species that significantly impact human health and marine ecosystems. Some Vibrio species cause serious foodborne illnesses in humans who consume contaminated seafood, while others contribute to coral bleaching and disease. However, certain Vibrio species also play important ecological roles in nutrient cycling and serve as bioluminescent symbionts in marine animals like squid.

Pseudomonas species

These versatile bacteria are found throughout marine environments and include species with remarkable abilities to break down pollutants, making them valuable for bioremediation of contaminated marine habitats. Some Pseudomonas species can degrade oil spills and other environmental contaminants, while others play important roles in marine food webs by recycling nutrients.

Oikopleura species (dioica, parva, fusiformis, albicans)

These small, tadpole-like marine animals create elaborate mucus “houses” that act as efficient filters, capturing tiny particles from seawater. They play a crucial role in ocean food webs by packaging small particles into larger ones that can be eaten by fish and other marine animals, essentially serving as a biological link between microscopic plankton and larger marine life.

Doliolum species (denticulatum, nationalis)

These barrel-shaped marine animals are important members of the zooplankton community and can form massive swarms that significantly impact ocean ecosystems. They feed on phytoplankton and bacteria while serving as food for commercially important fish species, making them crucial links in marine food webs that ultimately support human fisheries.

Thalia democratica

This barrel-shaped marine organism, known as a salp, can form long chains of individuals and plays an important role in ocean carbon cycling. Salps are efficient filter feeders that can clear large volumes of water, consuming phytoplankton and bacteria while producing dense fecal pellets that rapidly sink to the deep ocean, effectively transporting carbon away from the atmosphere.

Littorina littorea (common periwinkle)

This small sea snail is both an important herbivore in rocky intertidal ecosystems and a traditional food source in many coastal regions, particularly in Europe. Common periwinkles help control algae growth on rocky shores and serve as food for numerous seabirds, crabs, and fish, making them keystone species in coastal marine ecosystems.

Potential HAB or NIS: Detections of species that are non-indigenous to the southwest Pacific and species from taxa that have the potential to form Harmful Algal Blooms. Reference lists for each of these groups are continuously evolving. Please note that detection of these species does not necessarily indicate an active threat but rather, highlights trends that may be of interest to explore further. Please Note: No potential NIS species were detected in this dataset

Dinoflagellates and the mechanism

Alexandrium saxitoxins – PSP

Karenia brevetoxins – NSP

Dinophysis okadaic acid – DSP

Gambierdiscus ciguatoxins – CFP

Prorocentrum DSP toxins, including okadaic acid

Ostreopsis palytoxins

Ceratium can cause hypoxia, but usually not toxic Lingulodinium may produce yessotoxins

Gymnodinium some species produce brevetoxins or ichthyotoxins

Diatoms and the mechanism

Pseudo-nitzschia domoic acid – ASP

Raphidophytes and the mechanism

Heterosigma fish kills – not via toxins but through gill damage

Chattonella fish-killing blooms, possible ROS involvement

Cyanobacteria and the mechanism

Trichodesmium may contribute to HABs through oxygen depletion or toxin production in some contexts

Kappaphycus alvarezii

Codium arenicola

Codium taylori

Ulva ohnoi

Olstreopsis ovata

Didemnum perlucidum

Amathia distans

Amathia verticillata

Bugula neritina

Schizoporella errata

Watersipora subtorquata

Amphibalanus amphitrite

Penaeus indicus

Penaeus merguiensis

Panaeus monodon

Panaeus stylirostris

Panaeus vannamei

Godiva quadricolor

Magallana belcheri

Crassostrea virginica

Magallana bilineata

Magallana gigas

Mytilopsis sallei

Ostrea edulis

Perna viridis

Pinctada imbricata

Pinctada maxima

Pinctada margaritifera

Rochia nilotica

Ruditapes philippinarum

Saccostrea echinata

Saccostrea glomerata

Turbo marmoratus

Sabellastarte spectabilis

Mycale (Zygomycale) parishii

Mugil cephalus

Salmo trutta

Eriocheir sinensis

Rhithropanopeus harrisii

Hemigrapsus sanguineus

Charybdis japonica

Mytilopsis sallei

Perna perna

Arcuatula senhousia

Mytella strigata

Batis maritima

Detections of marine vertebrates including any fish, marine mammals, marine reptiles, and marine birds detected. Hover over each sampling location to reveal which taxa was detected at that location.