Coral Recruits Surveys

Overview

The coral recruits survey dataset captures early-stage coral recruitment patterns through systematic juvenile colony assessments. Surveys target small coral colonies (maximum diameter <5 cm) using standardized quadrat sampling along transect lines.

Standard Survey Methodology

Spatial Design: Fixed-interval quadrat placement at 5-meter increments along 50-meter transects

Sampling Units: Ten 0.5×0.5 meter quadrats per transect (0.25 m² each; 2.5 m² total per transect)

Target Organisms: Live, independent juvenile coral colonies only (excludes fragmented or attached polyps)

Taxonomic Resolution: Genus-level identification with morphometric measurements

Data Capture: Each recruit is identified, measured (maximum diameter), and geolocated by quadrat position

---

Data Architecture

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

• uvs.recruits_observations - One row per individual recruit, with genus, size, and quadrat location
• uvs.recruits_stations - One row per UVS station, with metadata, survey effort, and summary metrics
• uvs.recruits_density_by_station_taxa - Aggregated counts and densities by genus for each station

All tables link via ps_station_id. Taxonomy uses accepted_aphia_id as the canonical key to taxa_info.benthos; accepted_name is denormalized for convenience. Site context (region, subregion, locality, habitat, exposure) mirrors uvs.sites and may be materialized or exposed via a view.

Relational Model

Primary Key Relationships:

• All tables link via ps_station_id (composite station identifier)
• Taxonomic joins use accepted_aphia_id → taxa_info.benthos
• 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.

---

Tables

---

Observations

Purpose: Granular observation-level data capturing individual coral recruits within quadrats

Grain: One row per juvenile coral colony observation

Use Cases:

• Size-frequency distribution analysis
• Within-transect spatial variation assessment (quadrat-level patterns)
• Substrate association analysis
• Individual-level taxonomic validation and QA
• Raw data export for custom aggregations

Table 1: Schema for uvs.recruits_observations: coral recruit observations by quadrat

Field	Type	Required	Description
obs_id	STRING	true	Unique observation identifier. Format: {ISO3}_{YEAR}_recruits_{DIVER_INITIALS}_{SEQUENCE}
ps_station_id	STRING	true	Station identifier (FK → uvs.recruits_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)
transect_length_m	INTEGER	true	Transect length (m). Standard = 50
quadrat	INTEGER	false	Quadrat number (1–10)
quadrat_area_m2	FLOAT	true	Quadrat area (m²). Standard = 0.25
accepted_name	STRING	true	Valid scientific name (typically genus)
accepted_aphia_id	INTEGER	true	WoRMS AphiaID (FK → taxa_info.benthos)
rank	STRING	true	Taxonomic rank: species, genus, or family
family	STRING	false	Coral family name
count	INTEGER	true	Number of individuals of this taxon
diameter_cm	FLOAT	true	Colony diameter (cm)
substrate	STRING	false	Substrate type at recruit attachment point (e.g., CCA, rock, rubble)
notes	STRING	false	Optional comments or QA annotations

---

Stations

Purpose: Station-level metadata and summary statistics for coral recruit surveys

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

Use Cases:

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

Table 2: Schema for uvs.recruits_stations: metadata and summary metrics for coral recruit 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	INTEGER	true	Number of transects completed
n_quadrats	INTEGER	true	Total quadrats sampled
survey_dist_m	FLOAT	true	Total transect distance (m)
survey_area_m2	FLOAT	true	Total area sampled (m²)
n_taxa	INTEGER	true	Number of distinct taxa observed
total_count	INTEGER	true	Total number of recruits
avg_density_m2	FLOAT	true	Mean recruit density (individuals/m²)
notes	STRING	false	Station-level annotations or QA notes

---

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
• Family-level or genus-level recruitment pattern comparisons
• 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.recruits_density_by_station_taxa: coral recruit density summaries by station and taxon

Field	Type	Required	Description
ps_station_id	STRING	true	Station identifier (FK → uvs.recruits_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	INTEGER	true	Number of transects completed
n_quadrats	INTEGER	true	Total quadrats sampled
survey_area_m2	FLOAT	true	Total area sampled (m²)
accepted_name	STRING	true	Valid scientific name (typically genus)
accepted_aphia_id	INTEGER	true	WoRMS AphiaID (FK → taxa_info.benthos)
rank	STRING	true	Taxonomic rank: species, genus, or family
family	STRING	false	Coral family name
total_count	INTEGER	true	Total recruits for this taxon at station
n_quadrats_present	INTEGER	false	Number of quadrats where taxon was observed
avg_density_m2	FLOAT	true	Mean density for this taxon (individuals/m²)
avg_diameter_cm	FLOAT	true	Mean colony diameter for this taxon (cm)