California Seahare
Aplysia californica
Description 2
This large, black/brown/purple sea slug looks like a small football with rabbit ears. While generally more of a Southern California creature, they make it up into the Bay (and Lake Merritt) during periods of warmer ocean temperatures and onshore currents, e.g. during El Niño events of varying intensity. When present, they can often be observed in large clusters, feeding, mating, and producing bunches of egg ribbons that look like yellow silly string.
Morphology 3
The California Black Sea Hare is probably the world's largest gastropod. It can weigh up to 35 pounds! It is typically about 16" long (41 cm) and 8" (20 cm) wide and high. Plump and soft, it has winglike flaps around the top of its head on both sides. Aplysia californica can be reddish, brownish, or greenish, spotted with white or dark circles and lines. The colors reflect the type and color of algae they are prone to eat. They feed with a pair of jaws and a grasping radula. On top of their head, two pairs of antennae are found: one low near the mouth and another behind the eyes. A foot used to help in locomotion extends a little farther than the entire length of the animal. The anterior tentacles are much larger and ear-like (thus its common name- the sea hare) than the second pair which are used more for smelling. They also possess winglike flaps called parapodia that are used for swimming. The mantle folds over and covers a thin, transparent, and flexible shell. In its wall are unicellular glands that secrete a purple dye when the animal is handled. The sea hare does possess a developed nervous and digestive system. In its digestive tract there is an alimentary canal in front of the stomach that ends in a crop lined with horny plates for better mastication before digestion of food.
Other Physical Features: ectothermic ; bilateral symmetry
Feeding 4
Aplysia californica are herbivorous and feed on a variety of algae and eelgrass. Their pair of jaws and broad rasp-like radula help crop the seaweed they eat. The color of the particular animal matches the color of the algae or vegetation they feed on the most.
Reproduction 5
A. californica is hermaphroditic. Armed with a single aperture and duct for the sperm and ova, this species reproduces sexually. They travel to deeper waters to spawn around spring time. Once fertilized, their eggs are laid down in pink, gelatin-like stringed sacs coiled around seaweed or rocks.
Distribution 6
This species is found on the Pacific coast of California, United States, and northwestern Mexico (including the Gulf of California). Aplysia inhabit the photic zone to graze on algae, mainly the intertidial and sub-littoral zones usually not deeper than 18-20 m.
Uses 7
Aplysia californica are used extensively in studies of behavior, reproduction, and development in such fields as chemistry, biology, and psychology.
2015 Appearance 2
During the warmer ocean conditions of 2014 and 2015, these slugs appeared in droves around the southern part of the lake, part of a northern expansion observed in many marine species more common in the south (Kraybill-Voth, 2015). Many slugs washed up on Bay Area beaches, causing numerous people to mistake them for human organs, resulting in some absurd international news coverage.
Sources and Credits
- (c) Ken-ichi Ueda, some rights reserved (CC BY), uploaded by Ken-ichi Ueda
- (c) Ken-ichi Ueda, some rights reserved (CC BY-SA)
- (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31378274
- Adapted by Ken-ichi Ueda from a work by (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31378276
- Adapted by Ken-ichi Ueda from a work by (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31378275
- Adapted by Ken-ichi Ueda from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/California_sea_hare
- Adapted by Ken-ichi Ueda from a work by (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31378277
More Info
iNat Map
| Category | Snails & Slugs |
|---|---|
| Region of origin | California |
