Bristly Tunicate

About this species

Halocynthia igaboja, commonly known as sea hedgehog, bristly tunicate or spiny sea squirt, is a species of tunicate in the family Pyuridae. It is native to the northeastern Pacific Ocean. This species was first described in 1906 by the Japanese marine biologist Asajiro Oka, who gave it the name Cynthia ritteri. It was later transferred to the genus Halocynthia.

Text from the Wikipedia article “Halocynthia igaboja”, licensed CC BY-SA 4.0. Read the article

Where and when

Where it has been recorded

Worldwide

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Best months

Worldwide (open data)

January: 92 records
February: 128 records
March: 92 records
April: 90 records
May: 101 records
June: 127 records
July: 107 records
August: 138 records
September: 133 records
October: 123 records
November: 76 records
December: 52 records

Depth and water temperature

Depth

Mostly recorded at 16–50 m · Deepest record: 1,500 m

0–10 m: 16 records
10–20 m: 307 records
20–30 m: 490 records
30–40 m: 122 records
40–50 m: 16 records
50–60 m: 16 records
60–70 m: 2 records
70–80 m: 1 records
80–90 m: 3 records
90–100 m: 2 records
100–110 m: 15 records
110+ m: 75 records

Water temperature

Recorded in surface water of -1–20 °C

-2–0 °C: 38 records
0–2 °C: 44 records
2–4 °C: 0 records
4–6 °C: 1 records
6–8 °C: 12 records
8–10 °C: 101 records
10–12 °C: 580 records
12–14 °C: 8 records
14–16 °C: 0 records
16–18 °C: 4 records
18–20 °C: 8 records

Photos

(c) Matt Muir, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Erin McKittrick, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Rachel Crane, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Matt Muir, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Erin McKittrick, some rights reserved (CC BY) · CC BY · iNaturalist

Names and classification

English: Bristly Tunicate, Sea Hedgehog, Spiny Sea Squirt

Other scientific names: Cynthia ritteri, Halocynthia jakoboja, Halocynthia owstoni, Halocynthia ritteri, Pyura okai, Tethyum igaboja

Similar species

Sources and credits

Names and taxonomy: WoRMS (CC BY 4.0) and the GBIF Backbone (CC BY 4.0). Photos: iNaturalist observers, each under the licence shown (CC0, CC BY or CC BY-SA).

Depth, temperature, months and maps: records from OBIS and GBIF under CC0 or CC BY.
Descriptions: Wikipedia, licensed CC BY-SA, each linked to its article.
Conservation status as published by GBIF (IUCN Red List).
1,129 open-data records from 1888 to 2025.
Species data updated November 3, 2026.