Invertebrates Surveys

Overview

The invertebrate survey protocol quantifies the diversity, abundance, and size distribution of motile reef invertebrates at Pristine Seas UVS sites. Divers swim along fixed transects and record invertebrate observations within defined belt widths, using two complementary methods:

• Standard invertebrate survey — All motile invertebrates within 1 meter of one side of the transect are counted and identified to the lowest possible taxonomic level
• Large-scale invertebrate survey (optional) — Culturally and fishery-important species are measured for size within a wider 4-meter belt on the opposite side of the transect

This dual protocol captures both fine-scale community composition and large-bodied target species for management applications.

Standard Survey Methodology

Spatial Design: Fixed-length transects with variable belt widths depending on survey type

Sampling Units: - 50-meter transect × 1-meter belt (50 m² per transect) for general invertebrate counts - 50-meter transect × 4-meter belt (200 m² per transect) for large-bodied species measurements (not always done)

Target Organisms: Motile reef invertebrates including echinoderms, molluscs, crustaceans, and other conspicuous taxa

Taxonomic Resolution: Species-level identification where possible, with genus or family fallback

Data Capture: Each taxon is counted and, for selected large-bodied species, measured for size

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Data Architecture

The dataset employs a three-tier normalized structure linking individual observations to station-level summaries and taxonomic aggregations.

• uvs.inverts_observations - One row per taxon per transect, with counts and optional size measurements
• uvs.inverts_stations - One row per UVS station, with metadata, survey effort, and summary metrics
• uvs.inverts_density_by_station_taxa - Aggregated counts and densities by taxon for each station

All tables link via ps_station_id. Taxonomy uses accepted_aphia_id as the canonical key to taxa_info.inverts; accepted_name is denormalized for convenience. Site context (region, subregion, locality, habitat, exposure) mirrors uvs.sites.

Relational Model

Primary Key Relationships:

• All tables link via ps_station_id (composite station identifier)
• Taxonomic joins use accepted_aphia_id → taxa_info.inverts
• Spatial context inherits from uvs.sites via ps_site_id

Denormalization Strategy:

Site context fields (region, subregion, locality, habitat, exposure) are denormalized in summary tables to optimize query performance for common filtering operations.

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Tables

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Observations

Purpose: Granular observation-level data capturing invertebrate counts and sizes within transects

Grain: One row per taxon observation

Use Cases:

• Size-frequency distribution analysis for large-bodied species
• Taxonomic composition assessment at transect level
• Survey effort validation and QA
• Raw data export for custom aggregations
• Individual-level taxonomic verification

Table 1: Schema for uvs.inverts_observations: invertebrate observations by transect

Field	Type	Required	Description
obs_id	STRING	true	Unique observation identifier. Format: {ISO3}_{YEAR}_inverts_{DIVER_INITIALS}_{SEQUENCE}
ps_station_id	STRING	true	Station identifier (FK → uvs.inverts_stations)
exp_id	STRING	true	Expedition identifier. Format: {ISO3}_{YEAR}
diver	STRING	true	Observer name
depth_m	FLOAT	true	Recorded depth (m)
transect	STRING	true	Transect label (A, B, OFF)
transect_length_m	INTEGER	true	Transect length (m). Standard = 50
transect_width_m	INTEGER	true	Belt width (m). 1m for counts, 4m for measurements
morphotaxon	STRING	true	Field identification name
accepted_name	STRING	true	Valid scientific name
accepted_aphia_id	INTEGER	true	WoRMS AphiaID (FK → taxa_info.inverts)
rank	STRING	true	Taxonomic rank: species, genus, or family
family	STRING	false	Family name
common_name	STRING	false	Common name (e.g., sea cucumbers, giant clams)
count	INTEGER	true	Number of individuals of this taxon
size_cm	FLOAT	false	Measured length (cm), when applicable
size_type	STRING	false	Measurement type (e.g., shell width, total length)
notes	STRING	false	Optional comments or QA flags

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Stations

Purpose: Station-level metadata and summary statistics for invertebrate surveys

Grain: One row per depth-stratified UVS station with invertebrate sampling

Use Cases:

• Survey effort tracking and validation
• Station-level community metrics comparisons
• Depth-stratified analysis
• Regional and habitat-level summaries
• Data completeness auditing

Table 2: Schema for uvs.inverts_stations: metadata and summary metrics for invertebrate survey stations

Field	Type	Required	Description
ps_station_id	STRING	true	Unique station identifier. Format: {ps_site_id}_{depth}
ps_site_id	STRING	true	Site identifier (FK → uvs.sites)
exp_id	STRING	true	Expedition identifier. Format: {ISO3}_{YEAR}
region	STRING	true	Geographic region (from uvs.sites)
subregion	STRING	true	Geographic subregion (from uvs.sites)
locality	STRING	false	Specific locality (from uvs.sites)
habitat	STRING	true	Habitat classification (from uvs.sites)
exposure	STRING	true	Wave exposure category (from uvs.sites)
depth_strata	STRING	true	Depth category: supershallow, shallow, or deep
depth_m	FLOAT	true	Mean recorded depth (m)
divers	STRING	true	Pipe-delimited list of observer names
n_transects	FLOAT	true	Number of transects completed
survey_dist_m	FLOAT	true	Total transect distance (m)
survey_area_m2	FLOAT	true	Total area sampled (m²)
n_taxa	INTEGER	false	Number of distinct taxa observed
total_count	INTEGER	false	Total number of invertebrates
avg_density_m2	FLOAT	false	Mean invertebrate density (individuals/m²)
notes	STRING	false	Station-level annotations or QA notes

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Density by Station & Taxa

Purpose: Pre-aggregated taxon-specific density metrics at station level

Grain: One row per station × taxon combination (only taxa present at station)

Use Cases:

• Taxonomic composition analysis without repeated aggregation
• Target species assessments (e.g., giant clams, sea cucumbers)
• Efficient filtering for specific taxa across regions/habitats
• Rapid dashboard queries (pre-computed densities)
• Community structure metrics (diversity indices, dominance)

Table 3: Schema for uvs.inverts_density_by_station_taxa

Field	Type	Required	Description
ps_station_id	STRING	true	Station identifier (FK → uvs.inverts_stations)
ps_site_id	STRING	true	Site identifier (FK → uvs.sites)
exp_id	STRING	true	Expedition identifier. Format: {ISO3}_{YEAR}
region	STRING	true	Geographic region (from uvs.sites)
subregion	STRING	true	Geographic subregion (from uvs.sites)
habitat	STRING	true	Habitat classification (from uvs.sites)
exposure	STRING	true	Wave exposure category (from uvs.sites)
depth_strata	STRING	true	Depth category: supershallow, shallow, or deep
depth_m	FLOAT	true	Mean recorded depth (m)
divers	STRING	true	Pipe-delimited list of observer names
n_transects	FLOAT	true	Number of transects completed
survey_area_m2	FLOAT	true	Total area sampled (m²)
morphotaxon	STRING	true	Field identification label
accepted_name	STRING	true	Valid scientific name
accepted_aphia_id	INTEGER	true	WoRMS AphiaID (FK → taxa_info.inverts)
rank	STRING	true	Taxonomic rank: Species, Genus, or Family
family	STRING	false	Family name
common_name	STRING	false	Common name (e.g., sea cucumbers, giant clams)
total_count	INTEGER	true	Total individuals for this taxon at station
avg_density_m2	FLOAT	true	Mean density for this taxon (individuals/m²)
avg_size_cm	FLOAT	false	Mean size for this taxon (cm), when measured