common sea hare vs Common Stonewort

Aplysia punctata compared with Chara vulgaris

Key Differences

• common sea hare is Least Concern while Common Stonewort is Endangered.

Taxonomic Classification

Rank	common sea hare	Common Stonewort
Kingdom	Animalia (Animals)	Plantae (Plants)
Phylum	Mollusca (Mollusks)	Charophyta (Charophyta)
Class	Gastropoda (Gastropoda)	Charophyceae (Charophyceae)
Order	Aplysiida (Aplysiida)	Charales (Charales)
Family	Aplysiidae	Characeae
Genus	Aplysia	Chara
Species	Aplysia punctata	Chara vulgaris

Conservation Status

common sea hare

LC — Least Concern

Common Stonewort

EN — Endangered

Physical Characteristics

Attribute	common sea hare	Common Stonewort
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

common sea hare

Habitat

Typically found in terrestrial and aquatic habitats including forests and freshwater.

Range

Distributed across Denmark, Norway, Portugal, and Sweden.

Common Stonewort

Habitat

Native to Asia and Europe and North America, inhabiting ecosystems characteristic of the region.

Range

Widely distributed across Asia (Taiwan), Europe (Denmark, Norway, Sweden), North America (United States), and South America (Brazil). Currently classified as Endangered on the IUCN Red List, this species faces significant conservation challenges across its range.

common sea hare

<em>Aplysia punctata</em>, the common sea hare, is a large opisthobranch sea slug in the family Aplysiidae, order Aplysiida, found in the northeastern Atlantic Ocean and Mediterranean Sea, with confirmed records from Denmark, Norway, Portugal, and Sweden. This species typically inhabits shallow subtidal and intertidal zones with abundant macroalgae, feeding primarily on red and green algae — a diet that influences the color of the defensive purple ink it secretes when threatened. <em>Aplysia punctata</em> is a simultaneous hermaphrodite, capable of acting as both male and female during mating, and often forms mating chains involving multiple individuals. It can reach considerable size among European opisthobranch species, though body dimensions vary considerably with age and feeding conditions. The species is classified as Least Concern by the IUCN, reflecting stable populations across its coastal range. Biological traits for this species remain poorly documented in the scientific literature, including precise average data on lifespan, body length, weight, and detailed seasonal dietary patterns, though its general herbivorous feeding on macroalgae is well established.

Common Stonewort

<em>Chara vulgaris</em>, the common stonewort, is a species of charophyte green alga in the family Characeae, order Charales. It typically grows submerged in freshwater habitats including ponds, lakes, ditches, and slow-moving streams, often forming dense mats on the substrate. The species has a broad geographic distribution spanning Asia, Europe, and the Americas, tolerating a range of water conditions from clear to moderately turbid. <em>Chara vulgaris</em> is notable for its heavily calcified, whorled structure that gives stoneworts their characteristic encrusted appearance and makes them valuable as paleoclimate indicators in sediment records. As a primary producer, it contributes to aquatic food webs and provides habitat for invertebrates and juvenile fish. Biological traits such as individual lifespan, precise growth rates, and specific consumer relationships remain poorly documented in the literature. Despite its wide range, <em>Chara vulgaris</em> is assessed as Endangered by the IUCN, reflecting significant population declines attributed to freshwater pollution, eutrophication, and habitat degradation across much of its range. Targeted conservation of clean, oligotrophic water bodies is essential for its persistence.

Shared Countries

Both species can be found in 3 countries:

🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden