Katharina tunicata

Biology/Natural History: There is a large amount of molecular and genetic research done on Katharina. The K. tunicata is diploid and has a haploid number of 24. The changes in organic composition of the tissues and systems along with the life cycle of the chiton have also been studied. Lipids and blood proteins levels are high through the majority of the life cycle, but both decrease dramatically prior to spawning. The organic compositions of most other systems remain fairly constant seasonally. Damaged plates can be repaired in just a few weeks. The diet of the black chiton includes brown and red algae as well as benthic diatoms. Reproduction is sexual and full maturity just over a year. The entire life span averages 3 years.

The body of Katharina tunicata can grow up to 12 cm long. The body is an elongated oval. The girdle is black, thick, shinny, and leathery; it covers all but the middorsal area. The valves are embedded in the girdle.

Common along Pacific Northwest Coast. Especially common in the San Jaun Islands and Strait of Jaun de Fuca (Niesen 1997).

Biogeographic Regions: nearctic (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (20,000-2,500,000 square km (about 8000-1,000,000 square miles)) Occurs from Kamchatka, Russia, through the Aleutian Islands, Alaska, to southern California (O'Clair and O'Clair 1998, Field and Field 1999, Slieker 2000).

Geographical Range: Alaska to Santa Barbara, Ca and in Kamchatka

Katharina tunicata is a medium sized chiton, with an average length of 7 cm. Its black girdle almost completely covers the eight whitish plates, leaving a diamond shaped pattern down the dorsal side. The plates are sometimes overgrown with algae, so they will appear green (Mohler 1997). Like most chitons, K. tunicata is oval shaped, but when removed from the rock it will ball up (Karleskint 1998). The underside of K. tunicata is commonly peach colored,and houses the gills and mouth. The foot is surrounded by mantle and is usually darker orange.

Length: 13 cm

How to Distinguish from Similar Species: The black chiton is easily distinguished from other chitons by the texture and color of the girdle.

Katharina tunicata is found in the middle and upper zones of the rocky intertidal, and can withstand hard wave action. This chiton is often seen near the borders of mussel clumps. (Niesen 1997; Mohler 1997)

Aquatic Biomes: coastal

Depth range based on 79 specimens in 1 taxon.
Water temperature and chemistry ranges based on 71 samples.

Environmental ranges
  Depth range (m): 0 - 73.2
  Temperature range (°C): 7.261 - 10.345
  Nitrate (umol/L): 5.634 - 14.311
  Salinity (PPS): 31.235 - 32.487
  Oxygen (ml/l): 5.882 - 6.794
  Phosphate (umol/l): 0.883 - 1.602
  Silicate (umol/l): 12.975 - 33.391

Graphical representation

Depth range (m): 0 - 73.2

Temperature range (°C): 7.261 - 10.345

Nitrate (umol/L): 5.634 - 14.311

Salinity (PPS): 31.235 - 32.487

Oxygen (ml/l): 5.882 - 6.794

Phosphate (umol/l): 0.883 - 1.602

Silicate (umol/l): 12.975 - 33.391
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Comments: Intertidal to 40m (Slieker 2000). Common on rocky shores with heavy wave action (Field and Field 1999, Gallivan and Danforth 1999, Ruesink 2003), usually found on stony or rocky bottoms in the lower middle intertidal zone and the lower intertidal zone (van de Hoek 2002). In Three Saints Bay, Kodiak Island, Alaska, favored habitats were crevices on vertical rock faces between individuals of barnacle Balanus cariosus, inside dead shells and on open rock surfaces (Nybakken 1969). Unlike most other chitons, K. tunicata tolerates direct sunlight (Nybakken 1969, O'Clair and O'Clair 1998, Field and Field 1999, van de Hoek 2002).

Depth Range: Very common in the middle and low inertidal zones

Habitat: They attach to rocks where they are exposed to heavy wave action.

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Katharina tunicata is an herbivore. Its main food sources are brown (Phaeophyta) and red (Rhodophyta) algae (Mohler 1997).

Comments: A moving grazer, diet varies regionally; eats many kinds of brown and red algae, including kelps, as well as Sea Lettuce (Ulva) and encrusting diatoms. Will also eat sponges, tiny barnacles, spirobid polychaetes and bryozoans (O'Clair and O'Clair 1998).

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: > 300

>1,000,000 individuals

Comments: A common inhabitant of middle to lower intertidal zones from Kamchatka, Russia and the Aleutian Islands, Alaska to Southern California (Field and Field 1999, Kozloff 2003).

Predators include humans, sea urchins, leather stars, Black Oystercatchers, and Glaucus-winged Gulls (O'Clair and O'Clair 1998).

Kathrina tunicata, like all chitons, has seperate sexes. Katharina tunicata spawns March through July. Chitons do not copulate; instead, the male release sperm and fertilzation occurs in the sea or in the mantle trough of the female, depending upon the species. After fertilization, eggs can be shed, or are brooded in the mantle cavity of the female. This is also species-dependent. Chitons have a free swimming (trochophore) larvae which develops into the adult(Dorit 1991).

Sexual maturity at 35mm in length. Spawns in spring in the southern part of its range; during summer further north (e.g. in June on the outer coast of Vancouver Island, British Columbia). Females broadcast eggs (O'Clair and O'Clair 1998) after nearby males shed their sperm (Barr and Barr 1983). Settlement and metamorphosis can be induced by the encrusting coralline alga, Lithothamnion spp. Onset of gonadal growth in fall is triggered by declining water temperatures. Final gamete production in spring requires increasing water temperatures. Adults live to three years in California, perhaps longer in Alaska (O'Clair and O'Clair 1998).

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 156
Specimens with Barcodes: 168
Species With Barcodes: 1

The following is a representative barcode sequence, the centroid of all available sequences for this species.

There are 124 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.

Download FASTA File

US Federal List: no special status

CITES: no special status

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Reasons: Very widespread in most of Alaska to British Columbia to southern California. plus Russian distribution.

Degree of Threat: Low

Comments: Intertidal zones may be affected by industrial activities, such as timber harvest, oil and gas development, mining, and seafood processing. Coastal development, sewage discharge, harvest of intertidal species for food, and over-visitation resulting in trampling and collecting by beachcombers are also of concern (Tindall 2004). Natural perturbations such as earthquakes and scouring incurred by major storms threaten subtidal and intertidal communities. Though little understood, the effects of global warming will likely result in changes in intertidal community structure and diversity; in California, researchers have already noted a reduction in cold-water species in intertidal communities attributed to warming water temperatures (Tindall 2004).

Biological Research Needs: Effects of subsistence harvest, trampling, and over-visitation on localized populations and community structure needs study. Research needed to examine the influence of size structure of prey and competitor species, algal production and productivity, and predation by sea otters and sea stars. Effects of global warming on species dynamics needs study. Indigenous ecological knowledge needs to be summarized for this species.

Global Protection: Very many (>40) occurrences appropriately protected and managed

Comments: In the U.S., protected under the Coastal Zone Management Act (CZMA) (USFWS 1995, NOAA 1996).

Needs: Intertidal areas receiving heavy human traffic should be conserved by restricting and/or monitoring access or regulating collections. Subsistence harvest should be monitored annually. In areas of high subsistence usage, population surveys are necessary to monitor stocks. Communication and collaboration with communities that use K. tunicata as a resource should be improved, and indigenous knowledge incorporated into management and decision making.