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Live Gap Analysis β€” Nigerian Marine Biodiversity Reference Library  v21

Tracking molecular barcode coverage for the Gulf of Guinea. Click any stat card or group below to filter the full species list. Taxa with absent status are undetectable in any eDNA survey β€” these are the highest priority for new voucher sequencing.

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Data verified from live database queries β€” March 2026
NCBI Nucleotide: queried via Biopython Entrez (50 priority West African taxa β€” v1 query). Remaining 57 taxa: status based on published literature. BOLD Systems (v5): API currently unavailable β€” query pending. Geographic filter when run: Nigeria, Ghana, Cameroon, Benin, Togo, Senegal, Guinea, CΓ΄te d'Ivoire, Liberia. Run bold_query_fallback.py locally for full BOLD verification. Coverage classification (v21, marker-specific): Present = WA records meet marker threshold (COI β‰₯5, 12S β‰₯3, 18S β‰₯1, 28S β‰₯1, rbcL β‰₯3) in both NCBI and BOLD/SILVA Β· Partial = WA records present but below threshold, or only one database covered Β· Absent = zero WA records in both databases.
Total taxa
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Sequences found
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Priority gaps
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Sequence coverage
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Nematode genera
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Coastal fish context

The Niger Delta and Gulf of Guinea coastal zone supports one of Africa's largest small-scale fisheries, with estimated annual artisanal landings exceeding 700,000 tonnes (FAO, 2020). Key species include Ethmalosa fimbriata (bonga shad), which continues to account for approximately 41.8% of the artisanal catch by weight in the Lagos Lagoon (Oladipo et al., 2025).

Reference library gap β€” West Africa

A global review of eDNA metabarcoding studies found that Sub-Saharan Africa has the lowest regional representation in molecular reference databases of any tropical region (Manaf et al., 2025, Molecular Ecology Resources). False negatives in eDNA surveys are therefore disproportionately common in West African biodiversity assessments, rendering standard metabarcoding protocols unreliable without a region-specific library.

MiFish 12S β€” the global standard

The MiFish primer set (Miya et al., 2015, Royal Society Open Science) targets a ~170bp region of the mitochondrial 12S rRNA gene and can detect over 230 fish species simultaneously from a single 2L water sample. It is now the most widely adopted fish eDNA marker globally, with reference sequences available for over 7,000 species β€” but fewer than 50 from the Gulf of Guinea specifically.

Taxon Common / role Group Marker NCBI (global/WA) BOLD / SILVA IUCN Priority Ecological notes
Showing β€” taxa
Gulf of Guinea Marine Ecosystems

Nigeria's EEZ covers approximately 210,000 kmΒ² of the Gulf of Guinea, one of the most productive marine ecosystems in the Atlantic. The Gulf of Guinea is characterised by a seasonal upwelling system that drives exceptionally high primary productivity, supporting both coastal small-scale fisheries and offshore industrial trawl and purse-seine operations (Cury & Roy, 1989, Canadian Journal of Fisheries and Aquatic Sciences). This tab covers truly marine species: offshore fish, reef taxa, marine invertebrates, seagrass, macroalgae, and offshore mammals. Primary markers: 12S rRNA (MiFish-U/E) for fish; COI (Leray-XT) for invertebrates and mammals; rbcL for plants and algae.

Gulf of Guinea endemics

Pteroscion peli, Lutjanus goreensis, and Scomberomorus tritor are among several species whose entire global range lies within or near the Gulf of Guinea. None have been barcoded from Nigerian waters. First-barcode records from this region would represent genuinely novel contributions to global sequence databases (Hebert et al., 2003, Proc. Royal Soc. B).

Sargassum inundations

Since 2011, massive Sargassum inundations have struck Nigerian coastal waters annually, impacting fisheries and coastal tourism (Wang et al., 2019, Science). eDNA-based monitoring using rbcL reference sequences enables source tracking and early warning detection before physical landfall.

Species Common name Group Marker NCBI BOLD / SILVA Priority Notes
Showing β€” species  Β·  Gulf of Guinea endemic species highlighted in blue
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FishBase β€” species checklists
OBIS β€” ocean biodiversity records
WoRMS β€” taxonomy authority
IUCN Red List β€” threatened spp.
BOLD Systems β€” barcodes
Since 2011, massive Sargassum inundations have increasingly impacted Nigerian coastal waters, smothering nearshore fish nurseries and fouling fishing gear. Two species β€” S. natans and S. fluitans β€” dominate these blooms. Having rbcL reference sequences from the Gulf of Guinea allows eDNA-based early detection and source tracking of bloom events, directly relevant to NMBL's monitoring mandate.
Several species in this list are endemic or near-endemic to the Gulf of Guinea β€” found nowhere else in the world. Pteroscion peli (boe drum), Lutjanus goreensis (Gorean snapper), and Scomberomorus tritor (West African Spanish mackerel) are examples with zero or near-zero sequences. These are the highest-priority targets because their barcodes do not exist anywhere β€” not just in Nigeria.
All Fish species β€” This tab consolidates all fish taxa from both estuarine/coastal and offshore marine environments. Primary marker: 12S rRNA (MiFish-U/E). Includes species from Lagos Lagoon, Niger Delta, nearshore and offshore Gulf of Guinea.
Species Common name Group Marker NCBI BOLD IUCN Priority Notes
Showing β€” fish species
Niger Delta / Lagos Lagoon context: Macrobenthos (animals >1mm) are the dominant component of estuarine and intertidal food webs. Tympanotonos fuscatus is the most abundant macrobenthic invertebrate in Niger Delta mangroves and a proven oil pollution indicator β€” populations collapse near spill sites. Primary marker for all groups: COI (Leray-XT primers). Secondary: 16S rRNA.
Species Common name Group Habitat Marker NCBI COI BOLD Priority Ecological role / notes
Showing β€” species  Β·  Tympanotonos and Pachymelania are highlighted β€” your named priority species
Most abundant macroinvertebrate in Niger Delta mangroves
Major protein source β€” sold in every coastal market
Population density drops >90% near oil spill sites
Used as biomonitor in Niger Delta pollution studies
Very few COI sequences from Nigeria in any database
Intertidal: 0.25mΒ² quadrat, hand-pick all visible fauna
Subtidal: Van Veen grab (0.1mΒ²), sieve through 1mm mesh
Mangrove: Timed search + area quadrat on prop roots
DNA: Foot/mantle tissue clip in 95% ethanol
Marker: COI with Leray-XT or universal primers
Niger Delta focus: Free-living nematodes are the most abundant multicellular animals in coastal sediment and the primary bioindicator of oil pollution. The nematode-to-copepod (N:C) ratio rises under organic enrichment and hydrocarbon contamination. Genera marked tolerant increase at polluted sites; sensitive genera decrease. Primary marker: 18S rRNA V1V2 (NF1/18Sr2b primers). Secondary: 28S D2D3 for species resolution.
Genus Order Pollution response Global 18S W.Africa 18S Nigeria 18S Global 28S Nigeria gap Ecological role
Showing β€” genera  Β·  0 red in Nigeria = priority gap  Β·  0 amber in Global = globally unsequenced  Β·  Row background: red = Nigeria gap   amber = globally unsequenced
N:C < 50 β€” unpolluted baseline
N:C 50–100 β€” moderate enrichment
N:C > 100 β€” heavy organic pollution
N:C > 1000 β€” severe contamination (e.g. oil spill sites)
SILVA SSU β€” most complete 18S nematode db
WoRMS β€” accepted taxonomy
NeMys β€” nematode species register
BOLD β€” barcode sequences