Hermissenda emurai

Overview

Scientific Name: Hermissenda emurai

Phylum: Mollusca

Class: Gastropoda

Order: Nudibranchia

Family: Facelinidae

Genus: Hermissenda

Species:

crassicornis [Describe here as A. iricolor]

Native Distribution

Origin Realm:

Temperate Northern Pacific

Native Region:

Origin Location:

Temperate Northern Pacific Sitka, Alaska to Puertecitos, Baja California (Wheeling et al. 2006) STATUS NOT STATED Bowie Seamount, NE Pacific Ocean (Mcdaniel et al. 2003) STATUS NOT STATED San Simeon, CA; Cape Flattery (Wheeling et al. 2006) STATUS NOT STATED Kodiak Island, Alaska to Baja California; also found in Japan (Harbo 1998) STATUS NOT STATED Northeast Pacific: Sitka, Alaska to Baja California; Coos Bay, OR (Beeman and Williams 1980, cited in Rudy et al. 1988) STATUS NOT STATED Pacific coast of North America, from Alaska to Mexico; Northwest Pacific: South Korea and Japan (Blackwell and Farley 2008) STATUS NOT STATED Central CA and OR coast (Carlton 2007) [Japan] Common at the Pacific coasts of north of Tohoku and Japan Sea, but rarely occurred at Izu Peninsula and southwards along the Pacific coasts. (Nakano 2004) STATUS NOT STATED [Japan] Hokota City, Ibaragi Prefecture, Pacific side. (Inoue et al. 2010) STATUS NOT STATED [West Coast of north America] From Alaska to Baja California. (Nakano 2004) STATUS NOT STATED [West Coast of north America] Sitka, Alaska to Baja California. (Beeman and Williams 1980, cited in Anonymous 1988) STATUS NOT STATED [As Dendice emurai (Synonymized taxom)] Muroran, Hokkaido; Asamushi, Mutsu Bay, northern Japan. (Abe 1964) STATUS NOT STATED [As Dendice emurai (Synonymized taxom)] Coasts of Niigata Prefecture and Sado Island, Toyama Bay and Echizen coast at Japan Sea side. (Abe 1964) STATUS NOT STATED Uncertain realm Alaska to Mexico (Sept 1999) STATUS NOT STATED

Geographic Range:

along the Pacific coast of North America, as far north as Alaska and as far south as Mexico; Northwest Pacific: South Korea and Japan (Blackwell and Farley 2008) Alaska to Mexico (Sept 1999) Geographical range: -132.400009155273 10.5, 3.30000019073486 54.2000007629395 (Ocean Biogeographic Information System) Sitka, Alaska to Puertecitos, Baja California (Wheeling et al. 2006)

General Diversity:

NF

Non-native Distribution

Invasion History:

No records of invasion (Global Invasive Species Database 2016)

Non-native Region:

Not applicable

Invasion Propens:

Not applicable

Status Date Non-native:

Not applicable

Vectors and Spread

Initial Vector:

Not applicable

Second Vector:

Not applicable

Vector Details:

Not applicable

Spread Rate:

Not applicable

Date First Observed in Japan:

NF

Date First Observed on West coast North America:

NF

Impacts

Impact in Japan:

NF

Global Impact:

used extensively as a research model to study the neurobiology of learning and memory, since it has a simple nervous system and classic conditioning behavior (Blackwell and Farley 2008)

Tolerences

Native Temperature Regime:

Cold water, Cool temperate, Mild temperate, Warm temperate, See details

Native Temperature Range:

Annual temperature range 9-18 degrees (Beeman and Williams 1980, cited in Rudy et al. 1988) *not specified if degrees C or F (only C makes sense); location not specified 9.967 - 16.269 °C (Ocean Biogeographic Information System 2016) Annual range 9-18ºC. (Anonymous 1988) Cold water, Cool temperate, Mild temperate, Warm temperate (M. Otani, pers. comm.)

Non-native Temperature Regime:

Not applicable

Non-native Temperature Range:

Not applicable

Native Salinity Regime:

Euhaline

Native Salinity Range:

[Coos Bay, OR] collected at 30 PPT (Rudy et al. 1988) Collected at 30 psu in Coos Bay. (Anonymous 1988) 31.893 - 37.969 PPS (Ocean Biogeographic Information System 2016)

Non-native Salinity Regime:

Not applicable

Temperature Regime Survival:

Cold water, Cool temperate, Mild temperate, Warm temperate, See details

Temperature Range Survival:

annual temperature range 9-18 degrees (Beeman and Williams 1980, cited in Rudy et al. 1988) *not specified if degrees C or F (only C makes sense); location not specified 9.967 - 16.269 °C (Ocean Biogeographic Information System 2016) Cold water, Cool temperate, Mild temperate, Warm temperate (M. Otani, pers. comm.)

Temperature Regime Reproduction:

Cold water, Cool temperate, Mild temperate, Warm temperate, See details

Temperature Range Reproduction:

In culture, H. c larvae took a minimum 30 days at 12 °C to metamorphose (Avila, 1998; Kuzirian et al., 1999, cited in Sisson 2005) Veligers hatch in 5-6 days in lab at 13-15 °C (Harrigan and Alkon 1978, cited in Rudy et al. 1988) Cold water, Cool temperate, Mild temperate, Warm temperate (M. Otani, pers. comm.)

Salinity Regime Survival:

Euhaline

Salinity Range Survival:

[Coos Bay] collected at 30 PPT (Rudy et al. 1988) 31.893 - 37.969 PPS (Ocean Biogeographic Information System 2016)

Salintiy Regime Reproduction:

Polyhaline, Euhaline

Salinity Range Reproduction:

Euhaline (M. Otani, pers. comm.)

Depth Regime:

Lower intertidal, Shallow subtidal, Deep subtidal

Depth Range:

Low intertidal zone, subtidal to 35m (Wheeling et al. 2006) [Bowie Seamount, NE Pacific Ocean] observed to 40 m depth (Mcdaniel et al. 2003) *new record for Bowie Seamount 0-18 m (Ocean Biogeographic Information System 2016) Intertidal to 35 m (Harbo 1998) Low intertidal, and subtidal down to 35m (Rudy et al. 1988) Intertidal and subtidal (Blackwell and Farley 2008) Low intertidal; subtidal down to 35m. (Beeman & Williams 1980, cited in Anonymous 1988)

Non-native Salinity Range:

Native Abundance:

Rare, Common, Abundant

Reproduction

Fertilization Mode:

Internal

Reproduction Mode:

Hermaphrodite/ monoecious

Spawning Type:

None

Development Mode:

Planktotrophic planktonic larva (feeding)

Asexual Reproduction:

Does not reproduce asexually

Reproduction Details:

In culture, H. c larvae took a minimum 30 days at 12 °C to metamorphose (Avila, 1998; Kuzirian et al., 1999, cited in Sisson 2005) [California] [Washington] Mating animals are usually found in winter in southern California; in Puget Sound, WA mating animals are found year-round; the pink egg string looks like linked sausages, often attached to algae and to blades of eelgrass. Each egg case contains one egg (can contain up to four) (Wheeling et al. 2006) Eggs are in pink sausage-like string; each 1 mm diameter, attached to substrate in a tight counterclockwise spiral; Each capsule may have 1 – 4 eggs; Mating animals and egg masses found all year in Puget Sound (Beeman and Williams 1980, cited in Rudy et al. 1988) Hermaphroditic; self- fertilization unlikely; eggs laid on algae or Zostera blades; egg-laying commences when animal is 45 days old, continues until death at 128+ days (in lab); motile sperm found in 34 mg animals, egg laying by 73 mg wild animals; veligers hatch in 5-6 days in lab at 13-15 °C; swimming veliger stage of at least 34 days; once veligers are at minimum 300 μ and have eyes, foot and enlarged propodium, metamorphosis occurs (Harrigan and Alkon 1978, cited in Rudy et al. 1988) Interactions before copulation last only 1-2 minutes, and the intromission, where animals exchange sperm, lasts a few seconds (Longley and Longley 1982) sperm from one copulation is only enough to fertilize 2-3 egg masses; amount of sperm an animal has affects the rate at which it produces egg masses; copulation most likely when animals meet head to head: they then sidle past eachother, line up the gonopores, evert their penises, exchange sperm, and then a lunging, biting behavior as they separate (Rutowski 1983) Aggressive lunging and biting behavior (thought to be violent) is now known to be part of a mating sequence; many attempts at copulation are unsuccessful;, but sperm from one copulation is enough to fertilize about 3 egg masses (Rutowski 1983, cited in Rudy et al. 1988) Before copulation, animal goes through a sequence of distinct precopulatory behaviors (Carlton 2007) Reproduction occurs year-round; hermaphroditic; no self-fertilization, copulation required; lays an egg mass; animals hatch from egg mass in 5-6 days as free-swimming, plankton-feeding veliger larvae; obligatory veliger stage of at least 34 days; after 34 days, competent veligers begin crawling on hydroids; in 12-24 hrs metamorphosis begins, and the velum, operculum, and shell are lost; metamorphose at a shell size of (~ 310 um); by 4-5 days after metamorphosis, the juvenile is taking on the diet, form, and behavior of the adult. reach reproductive maturity by about 1-1.5 months after metamorphosis; Generation time (egg-to-egg) can be as short as ~ 2.5 months (163 days in lab) (Blackwell and Farley 2008) Interaction leading to copulation in H. c. have a duration of only a minute or two, and intromission lasts only a few seconds. (Longley & Longley 1982)

Adult Mobility:

Actively mobile (Mobility is a normal part of at least part of the adult life cycle - at least in spurts. Not dependent upon distance traveled)

Adult Mobility Details:

swimming escape response to seastar predator Crossaster (Birkeland 1974, cited in Rudy et al. 1988)

Maturity Size:

In lab, motile sperm found in 34 mg animals, egg laying in 73 mg wild animals (Harrigan and Alkon 1978, cited in Rudy et al. 1988) Metamorphose at a shell size of (~ 310 um) (Blackwell and Farley 2008) Fertile egg masses were deposited in the laboratory by wild specimen as small as 73 mg, and motile sperm were observed in squash preparations from wild individuals weighing 34 mg (1.12 cm body length). (Harrigan & Alkon 1978)

Maturity Age:

Egg-laying commences when animal is 45 days old (in lab) (Harrigan and Alkon 1978, cited in Rudy et al. 1988) Reach reproductive maturity by about 1-1.5 months after metamorphosis ( which occurs when veliger is at least 34 days old) (Blackwell and Farley 2008) Egg production in individuals from wild populations is estimated to begin at about 1.5 month post-metamorphosis aand continue until death at 5-8 gram. (Harrigan & Alkon 1978)

Reproduction Lifespan:

Egg-laying commences when animal is 45 days old, continues until death at 128+ days (in lab) (Harrigan and Alkon 1978, cited in Rudy et al. 1988) Reproduction occurs year-round; generation time (egg-to-egg) can be as short as ~ 2.5 months (163 days in lab) (Blackwell and Farley 2008) Egg masses appeared on fouling panels exposed for one month at a time throughout the year in Monterey Bay, California. (Harrigan & Alkon 1978)

Longevity:

in lab, an average life span of 163 days (35 veliger + 128 day adult); subannual species (Harrigan and Alkon 1978, cited in Rudy et al. 1988) Life span: not much more than 4 months (Sept 1999) Average life-span of laboratory-reared specimens encompass approximately 163 days (35 days veliger stage plus 128 days adult stage. (Harrigan & Alkon 1978)

Broods per Year:

reproduction occurs year-round; generation time (egg-to-egg) can be as short as ~ 2.5 months (163 days in lab) (Blackwell and Farley 2008)

Reproduction Cues:

aggressive lunging and biting behavior (thought to be violent) is now known to be part of a brief mating sequence; head-on combats with conspecifics usually part of mating sequence (Rutowski 1983, cited in Rudy et al. 1988) obligatory veliger stage of at least 34 days; after 34 days, competent veligers begin crawling on hydroids; in 12-24 hrs metamorphosis begins, and the velum, operculum, and shell are lost; metamorphose at a shell size of (~ 310 um); by 4-5 days after metamorphosis, the juvenile is taking on the diet, form, and behavior of the adult. reach reproductive maturity by about 1-1.5 months after metamorphosis; Generation time (egg-to-egg) can be as short as ~ 2.5 months (163 days in lab) (Blackwell and Farley 2008)

Reproduction Time:

[California] [Washington] Mating animals are usually found in winter in southern California; in Puget Sound, WA mating animals are found year-round (Wheeling et al. 2006) Reproduction occurs year-round; generation time (egg-to-egg) can be as short as ~ 2.5 months (163 days in lab) (Blackwell and Farley 2008) Egg masses appeared on fouling panels exposed for one month at a time throughout the year in Monterey Bay, California. (Harrigan & Alkon 1978)

Fecundity:

Lays an egg string; each egg case contains one egg (can contain up to four) (Wheeling et al. 2006) The number of eggs estimated per egg mass varied from 6.9X103 to 1.0X106. (Harrigan & Alkon 1978)

Egg Size:

Eggs are in pink sausage-like string; each 1 mm diameter, attached to substrate in a tight counterclockwise spiral. Each capsule may have 1 – 4 eggs (Beeman and Williams 1980, cited in Rudy et al. 1988) The average egg diameter was 65.4±1.2 μm. (Harrigan & Alkon 1978)

Egg Duration:

Veligers hatch from egg in 5-6 days in lab at 13-15 °C (Harrigan and Alkon 1978, cited in Rudy et al. 1988) Animals hatch from egg mass in 5-6 days (Blackwell and Farley 2008) Veriger hatch in 5-6 days at 13-15ºC. (Harrigan & Alkon 1978)

Early Life Growth Rate:

veligers hatch in 5-6 days from egg in lab at 13-15 °C; swimming veliger stage of at least 34 days; once veligers are at minimum 300 μ and have eyes, foot and enlarged propodium, metamorphosis occurs (Harrigan and Alkon 1978, cited in Rudy et al. 1988) in culture, H. c larvae took a minimum 30 days at 12 °C to metamorphose (Avila, 1998; Kuzirian et al., 1999, cited in Sisson 2005) veliger stage of at least 34 days; after 34 days, competent veligers begin crawling on hydroids; in 12-24 hrs metamorphosis begins; metamorphose at a shell size of (~ 310 um); by 4-5 days after metamorphosis, the juvenile is taking on the diet, form, and behavior of the adult (Blackwell and Farley 2008)

Adult Growth Rate:

To 5 cm (Harbo 1998) 30mm to 80 mm (Beeman and Williams 1980, cited in Rudy et al. 1988) Generation time (egg-to-egg) can be as short as ~ 2.5 months (163 days in lab) (Blackwell and Farley 2008) From 1 to day 70 post-metamorphosis increase in body length was approximately linear averaging 0.82±0.11mm per day. The growth rate slowed to 0.35±0.17 mm per day between days 71-120 post-metamorphosis. (Harrigan & Alkon 1978)

Population Growth Rate:

NF

Population Variablity:

more abundant in center of range (Sitka, Alaska to Puertecitos, Baja California); Common in spring and summer (Wheeling et al. 2006) [Coos Bay] small boat basin, Charleston: seasonally, especially in summer (Rudy et al. 1988)

Habitat

Ecosystem:

Rocky intertidal, Rocky subtidal, Fouling, Tide flats, Kelp forest, SAV, Other

Habitat Type:

Epibenthic, Epiphytic, Epizoic

Substrate:

Mud, Sand, Rock, Biogenic, Artificial substrate

Exposure:

Exposed, Semi-exposed

Habitat Expansion:

NF

Habitat Details:

Found in tide pools, rocky pools, marina floats, pilings, and mud flats (Wheeling et al. 2006) On rocks, eelgrass beds, floats, and other habitats (Harbo 1998) Low intertidal, and subtidal down to 35m; rocky tidepools, floats, mud and sand flats (Beeman and Williams 1980; Goddard 1985); eelgrass beds, sea pen beds (Puget Sound); bare rock, fouling panels (Rudy et al. 1988) Found in surfgrass beds and standing pools of kelp (like Laminaria spp.) left by the lowest low tides (Carlton 2007) Habitat: mud flats, eelgrass beds, docks, and rocky intertidal areas (Sept 1999) Rocky tidepools as well as floats, mud and sand flats. (Beem & Williams 1980; Goddard 1985, cited in Anonymous 1988) Eeelgrass beds (Puget Sound), bare rock (Anonymous 1988) Exposed, Semi-exposed (M. Otani, pers. comm.)

Trophic Level:

Predator

Trophic Details:

eats hydroids, small sea anemones, bryozoans, colonial ascidians (Aplidium solidum, botryllids), annelids, small crustacea, tiny clams, dead animals; will eat other Hermissenda (Wheeling et al. 2006) [Puget Sound, WA] main predator of the sea pen Ptilosarcus gurneyi (Wheeling et al. 2006) feeds on hydroids and a variety of organisms (Harbo 1998) Hydroids and anemones; cannibalistic in captivity (Carlton 2007) eats hydroids (Tubularia, Eudendrium, Sarsia) sea anemones, bryozoans, ascidians, annelids, clams, dead animals, other Hermissenda (but only when food is unavailable) (Goddard 1985) [Humboldt Co., CA] anthomedusae, leptomedusae and Velella velella (Jaeckl 1984) (Rudy et al. 1988) Generalis carnivore. (Avila et al. 1998) Eats hydroids, particularly in eelgrass; Tubularia, Eudendrium, Sarsia (Goddard 1985, cited in Anonymous 1988). Also small sea anemones, bryozoans, colonial ascidian Aplidium, botyrllid ascidians, annelids, small crustaceans and clams, dead animals. Will eat other Hermissenda (but probably only when other food not available Goddard 1985)). Subtidally in Puget Sound: sea pen Ptilosarcus (Birkeland 1974, cited in Anonymous 1988). In Humboldt Co., California, prey include anthomedusae, leptomedusae and chondrophore Velella velella (Jaeckl 1984, cited in Anonymous 1988). Veligers crawl on Obelia, a probable food (Harrigan and Alkon 1978). Except hydrozoa, It is known that H. c. eats squids, bivalves, sea anemones, ascidians, and Sessilflorae in Japan. (Nakano 2004) RELATED: [Aeolidacea (suborder)] predators of cnidarians (hydroids, sea anemones), some eat ascidians and dead fish (Kozloff 1990)

Forage Mode:

Generalist

Forage Details:

feeds on hydroids and a variety of organisms (Harbo 1998) generalist carnivore and scavenger (Rudy et al. 1988) [Monterey Harbor] often eats the upper parts of the zooids of the hydroid Aplidium solidum ( Abbott & Newberry 1980, cited in Carlton 2007) Generalis carnivore. (Avila et al. 1998) Eats hydroids, particularly in eelgrass; Tubularia, Eudendrium, Sarsia (Goddard 1985, cited in Anonymous 1988). Also small sea anemones, bryozoans, colonial ascidian Aplidium, botyrllid ascidians, annelids, small crustaceans and clams, dead animals. Will eat other Hermissenda (but probably only when other food not available Goddard 1985)). Subtidally in Puget Sound: sea pen Ptilosarcus (Birkeland 1974, cited in Anonymous 1988). In Humboldt Co., California, prey include anthomedusae, leptomedusae and chondrophore Velella velella (Jaeckl 1984, cited in Anonymous 1988). Veligers crawl on Obelia, a probable food (Harrigan and Alkon 1978). Except hydrozoa, It is known that H. c. eats squids, bivalves, sea anemones, ascidians, and Sessilflorae in Japan. (Nakano 2004)

Natural Control:

COMPETITION [Competition] [Agression] nudibranch Phidiana hiltoni may attack H. crassicornis (Goddard et al. 2011); H. c is aggressive with conspecifics: when two individuals encounter eachother or have head on contact, fights break out, that involve lunging and biting; the winner is usually the one who gets the first bite in (Wheeling et al. 2006) *However, head- on combats with conspecifics usually part of mating sequence (Rutowski 1983, cited in Rudy et al. 1988) PREDATION [Predation] [Monterey, California] the large opisthobranch Navanax inermis is a predator of H.c in rocky areas (Beeman and Williams 1980, cited in Rudy et al. 1988) [Predation] [Puget Sound] seastar Crossaster likes H.c as summer food; small H. crassicornis have a swimming escape response to Crossaster (Birkeland 1974, cited in Rudy et al. 1988) [Predation] Eggs eaten by sacoglossan Olea hansineensis (Crane 1971, cited in Rudy et al. 1988) [Predation] prey to mosshead warbonnet fish, and the opisthobranchs Navanax and Pleurobranchaea (Blackwell and Farley 2008) [Predation] In rocky areas below Monterey, California, the large opisthobranch Navanax inermis (Beeman and Williams 1980). Seastar Crossaster (Puget Sound (Birkeland 1974, cited in Anonymous 1988)) prefers Hermissenda as summer food. Eggs eaten by sacoglossan Olea hansineensis (Crane,1971, cited in Anonymous 1988). PARASITES [Parasites] Copepod Hemicyclops thysanotus often found on its back (Beeman and Williams 1980, cited in Anonymous 1988).

Associated Species:

EPIBIONTS [Epibionts] copepod Hemicyclops thysanotus is often found on the dorsal surface of H. crassicornis (Wheeling et al. 2006) [Epibionts] copepod Hemicyclops thysanotus often found on its back (Beeman and Williams 1980, cited in Rudy et al. 1988) [Epibiont] [Puget Sound, WA] H.c is associated with the sea pen Ptilosarcus (Birkeland 1974, cited in Rudy et al. 1988) [Epibionts] Hemicyclops thysanotus occurs on H. crassicornis (Carlton 2007) SYMBIONTS [Symbionts] the eye of H. crassicornis has five cells, each about 75 um in diameter: it is suspected that the cells contain symbiotic fungi (Wheeling et al. 2006) PARASITES [Parasites] Copepod Hemicyclops thysanotus often found on its back (Beeman and Williams 1980, cited in Anonymous 1988).

References and Notes

References:

Abe T (1964) Opisthobranchia of Toyama Bay and adjacent waters. Baba K (Supervised) and the biological club, Takaoka Senior High School, Toyama Pref. (ed.), Hokuryu-kan Inc., Tokyo: 77-96 (English part). Anonymous (1988) Hermissenda crassicornis. Source unknown. https://scholarsbank.uoregon.edu/xmlui/bitstream/handle/1794/12748/H_crassicornis%20FINAL.pdf?sequence=1 Avila C, Tyndale E, Kuzirian AM (1998) Feeding behavior and growth of Hermissenda crassicornis (Molluca: Nudibranchia) in the laboratory. Marine and Freshwater Behaviour and Physiology 31: 1-19. Blackwell K and Farley J (2008) Hermissenda. Scholarpedia, 3(7):4090. http://scholarpedia.org/article/Hermissenda Acces Date: 28-Mar-16 Carlton, JT (2007) The Light and Smith manual: intertidal invertebrates from central California to Oregon. London, England: University of California Press, Ltd Global Invasive Species Database. http://www.iucngisd.org/gisd/search.php Access Date: 29-Mar-16 and 9-May-2016 Harbo RM (1998) Whelks to Whales: Coastal Marine Life of the Pacific Northwest. Madeira Park, BC Canada: Harbour Publishing Harrigan JF & Alkon DL (1978) Larval rearing, metamorphosis, growth and reproduction of the eolid nudibranch Hermissnda crasscornis (Eschscholtz, 1831). Biologica Bulletin 154: 430-439. http://www.biolbull.org/content/154/3/430.full.pdf+html?sid=8e3c569f-43a4-47ae-b438-d55fe9768064 Inoue H, Kamogawa M, Takashio O, Higano H, Namikawa H, Tanaka H, Saito N, Ikezawa H, Morino H (2010) Fauna of Marine Invertebrates from the Headland on the Kashimanada Coast and the Middle Coast of Ibaraki Prefecture (2006-2008). In: Report of Comprehensive Surveys of Plants, Animals and Geology in Ibaraki Prefecture by the Ibaraki Nature Museum. Ibaraki Nature Museum: 1-35pp. (in Japanese) Kozloff EN (1990) Invertebrates. Philadelphia, PA: Saunders College Publishing Longley RD & Longley AJ (1982) Hermissenda: agonistic behavior or mating behavior? The Veliger 24: 230-232. McDaniel N, Swanston D, Haight R, Reid D, Grant G (2003) Biological Observations at Bowie Seamount. Fisheries and Oceans Canada. http://www.dfo-mpo.gc.ca/Library/328294.pdf Nakano R (2004) Ophistobranchus of Japan Islands. Rutles, Inc., Tokyo: 304pp. (in Japanese) Ocean Biogeographic Information System. Hermissenda crassicornis. http://iobis.org/mapper/. Access Date: 26-Mar-16 Rudy P Jr, Rudy LH, Shanks A, Butler B (1988) Hermissenda crassicornis. In: Oregon Estuarine Invertebrates. University of Oregon. https://scholarsbank.uoregon.edu/xmlui/bitstream/handle/1794/12748/H_crassicornis%20FINAL.pdf?sequence=1&isAllowed=y Rutowski RL (1983) Mating and egg mass production in the aeolid nudibranch Hermissenda crassicornis (Gastropoda: Opisthobranchia). The Biological Bulletin. 165(1):276-85. Sept JD (1999) The Beachcomber's Guide to Seashore Life in the Pacific Northwest. Madeira Park, BC: Harbour Publishing Sisson CG (2005) Veligers from the nudibranch Dendronotus frondosus show shell growth and extended planktonic period in laboratory culture. Hydrobiologia. 541(1):205-13. Wheeling R, Helmstetler H, Cowles D (2006) Hermissenda crassicornis. http://www.wallawalla.edu/academics/departments/biology/rosario/inverts/Mollusca/Gastropoda/Opisthobranchia/Nudibranchia/Aeolidacea/Hermissenda%20crassicornis.htm Access Date: 26-Mar-16

Literature:

Extensive scientific information; peer-reviewed information; data specific to the location; supported by long-term datasets (10 years or more)

Notes:

NA