Big Rock Pool Challenge Biodiversity Report - Q1 2026

This report brings together all observations recorded through the Big Rock Pool Challenge up to March 2026, with a closer look at activity during Quarter 1 of 2026 (January–March).

All project data

The Big Rock Pool Challenge commenced in October 2024 at hubs located at Castle Beach, Falmouth and Mount Batten, Plymouth. In October 2025, seven new hubs joined the Big Rock Pool Challenge:

Shoeburyness, Southend-on-Sea
Kilve Beach, Somerset
Beadnell Haven, Northumberland
East Sands, St Andrews
Lee-on-the-Solent, Hampshire
Menai Bridge, Bangor
Ovingdean, Brighton

Data presented in this section of the report reflect all Big Rock Pool Challenge records from the start of the project in October 2024, until the end of Quarter 1 (end of March) 2026.

To view data from Quarter 1 of 2026 only, please see the second half of this report, or click here.

Overall Project Summary

23,379 observations · 711 contributors · 1,391 species

Species are grouped into higher-level “iconic taxa” categories based on their taxonomic ancestry. This grouping simplifies complex species-level data into broader biological categories (e.g. molluscs, crustaceans, algae), allowing clearer interpretation of community structure across sites and time periods.

The Big Rock Pool Challenge is powered by people. Every observation and identification is a contribution to a shared understanding of coastal biodiversity.

Some participants frequently attend events and submit records, while others help out by identifying species through verification on iNaturalist- all contributions are equally valuable in building the dataset.

For all project data until end of March 2026, records were submitted by 711 recorders, and verified to research grade by 1370 identifiers.

The top recorders and identifiers are presented below- thank you for your efforts!

Overall Top Recorders

aqualydon

1,030 records

keasty69

920 records

aliceyypoo

491 records

Overall Top Identifiers

aqualydon

3,831 identifications

mathijs_zonneveld

1,814 identifications

hamlet_ben

1,805 identifications

Each hub represents a local coastal site where volunteers return to record marine life over time. These locations form the backbone of the Big Rock Pool Challenge network.

Because each hub has been running for different lengths of time, and is explored by different groups of people, the number of records varies, but every contribution adds valuable information about rock pool communities at that site.

Hubs are arranged in alphabetical order.

Hub_ID	Hub	Observations	Contributors	Species
3	Beadnell Haven	1311	35	280
1	Castle Beach	12627	327	949
9	East Sands	526	32	170
8	Kilve Beach	405	14	131
2	Lee-on-the-Solent	1934	56	265
6	Menai Bridge	1165	53	311
7	Mount Batten	3790	168	521
4	Ovingdean	1081	42	212
5	Shoeburyness	540	20	159

During BioBlitz Battle games, all species recorded earn a score. These scores reflect how often this species is recorded in the overall Big Rock Pool Challenge dataset. The higher scoring species are those that are recorded less often within the project and may represent more unusual or less commonly observed species.

In this report, scores are given between 1-100, according to our current scoring system 2.1

The highest scoring species recorded during this period are presented below.

Highest Scoring Species Across All Project Data

Score: 100

Observed by
pixnaturalist

Hub
Mount Batten

Score: 100

Observed by
aliceyypoo

Hub
Castle Beach

Score: 100

Observed by
leonie48597

Hub
East Sands

Hub Summaries

A breakdown of records collected at each Big Rock Pool Challenge hub is presented below, including key contributors, iconic taxa grouping, and top scoring species.

Beadnell Haven

1,497 observations · 35 contributors · 280 species

Iconic Taxa Composition

Top iconic groups: Molluscs, Crustaceans, Brown algae

Top Recorders

janedixon13june70

253 observations

scubasteveseahouses

246 observations

georginafuller

173 observations

Top Identifiers

janedixon13june70

566 identifications

scubasteveseahouses

215 identifications

ffnaturalist

208 identifications

Top Scoring Species

Rhyssoplax polita

Rarity score: 100

Observed by
kiera_mccabe

Eulalia viridis

Rarity score: 75

Observed by
debsbon

Oscarella lobularis

Rarity score: 75

Observed by
michaelonthemountain