Aoroides secunda

Invasion History

First Non-native North American Tidal Record: 1996
First Non-native West Coast Tidal Record: 1996
First Non-native East/Gulf Coast Tidal Record:

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General Invasion History:

Aoroides secunda was described from the Sea of Japan, from Siakhu Bay and Sudzukhe Bay, near Vladivostok, Russia (Gurjanova 1938, Gurjanova 1951, cited by Ariyama 2004) and later found on the coast of Japan in the Seto Inland Sea, and in Suruga Bay, on the southern Pacific coast of Honshu (Ariyama 1993). It was reported from an offshore dredging-disposal area at the mouth of the Columbia River in 1995 (Hinton 1998), and was found in San Francisco Bay in 2004 (Cohen et al. 2005; Foss 2009), and many southern California bays (Cohen et al. 2002; Ranasinghe et al. 2005; California Department of Fish and Wildlife 2014).

North American Invasion History:

Invasion History on the West Coast:

The earliest report of A. secunda is from a dredge-disposal site ~16 km offshore/offshore from the mouth of the Columbia River, Oregon in 1995-1996, at depth range of 14-96 m (Hinton 1998). This site is different from the lower-intertidal to subtidal rocky-algal littoral and fouling community habitats reported for this species (Ariyama 1993). In Southern California, it was found in Mission Bay in a 1998 survey (Ranasinghe et al. 2005), and from Port Hueneme to San Diego Bay in 2000 (Cohen et al. 2002). In 2004, it was found in central San Francisco Bay, at the Presidio Yacht Club and Richmond Marina (Cohen et al. 2005). It was collected from the South Bay in 2005 (at Coyote Pt Marina, Foss 2009), but we have no records from San Pablo Bay, or the upper estuary. This amphipod is abundant on floats and pilings, and also among lower intertidal rocks and algae (Ariyama 1993; Chapman 2007). Ballast water and hull-fouling are likely vectors for the introduction of A. secunda.

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Description

Aoroides secunda has two antennae, which are relatively short, while Gnathopod 1 is very large and the peraeopods are relatively long. The body is somewhat slender and shallow, and the coxal plates are small. The eye is medium and oval. Plates 2-4 are rounded rectangles and plates 5-7 are smaller and oval. Antenna 1 is short and lacks the distal tip of the flagellum. Antenna 2 is stouter and has many setae on the posterior surface, but fewer on the anterior side. The flagellum is very short and consists of 2 segments.

The gnathopods are sexually dimorphic in this family. In males, the coxa of Gnathopod 1 is rounded and triangular with two spines anteriorly. Segments 1-6 are densely covered with setae on their anterior surface. Segment 6 also has dense setae on the posterior surface. Segment 2 is long and straight, and broader distally. Segment 4, called the merus, is lance-shaped and ends in a distal spine, curving behind the large, inflated segment 5, the carpus. Segment 6, the propodus is moderately inflated, while segment 7 is a medium-sized curved claw. The arrangement of the gnathopod is called 'merochelate', in which segments 5, 6 and 7 fold around segment 4 (the merus) to grip. In the female, Gnathopod 1 is much smaller than in males, with a rounded pentagonal coxa, a much shorter segment 2, no spine on segment 4, and fewer setae on the less-inflated segments 5 and 6. Gnathopod 1 is much larger than gnathopod 2 in males, but the two gnathopods are close to equal in females. Description based on Ariyama 2004 and Chapman 2007.

In A. secunda, peraeopods 3 and 4 have claws facing anteriorly, at their tips, while the claws of peraeopods 5-7 face backward. The uropods are biramous, with uropod 1 being longest, and uropod 3 shortest. Uropod 2 lacks a ventral inter-ramal spine on the peduncle, which is present in other members of the genus (Ariyama 2004; Chapman 2007). The largest specimen mentioned by Ariayama (2004) is 3.9 mm long, smaller than 5 species of native Aoroides spp., which reach 6-7 mm (Chapman 2007). The dorsal and posterior parts of the head and most of the pleonites and coxa, are brown, mottled with white. The anterior of the head and the appendages are white (Ariyama 2004).

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Taxonomy

Ecology

General:

Aoroides secunda is a tube-building amphipod, occurring on lower rocky intertidal and subtidal shores, among algae (Ariyama 2004), and also on floats and docks (Cohen et al. 2002; Chapman 2007). Gammarid amphipods have separate sexes, brooded embryos, and direct development (Bousfield 1973). We have no specific information on the life history of A. secunda in its native range in Japan.

Aoroides secunda appears to tolerate a wide range of temperatures, typical of the coast of western Asia (Ariyama 2004). We have not found records from brackish inner estuaries, so this amphipod may have limited tolerance to low salinities. Amphipods of the family Aoridae are suspension-feeding tube-builders (Chapman 2007).

Food:

Algae, detritus

Trophic Status:

Suspension Feeder

SusFed

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Habitats

General Habitat	Marinas & Docks	None
General Habitat	Grass Bed	None
General Habitat	Rocky	None
General Habitat	Unstructured Bottom	None
Salinity Range	Polyhaline	18-30 PSU
Salinity Range	Euhaline	30-40 PSU
Tidal Range	Subtidal	None
Tidal Range	Low Intertidal	None
Vertical Habitat	Epibenthic	None

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Tolerances and Life History Parameters

Maximum Length (mm)	3.9	Adult male (Ariyama 2004)
Broad Temperature Range	None	Cold temperate-Warm temperate
Broad Salinity Range	None	Polyhaline-Euhaline

General Impacts

No impacts are reported for the tube-building amphipod Aoroides secunda in West Coast waters.

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References

Ariyama, Hiroyki (2004) Nine species of the genus Aoroides (Crustacea: Amphipoda: Aoridae) from Osaka Bay, central Japan., Publication of the Seto Marine Biological Laboratory 40(1/2): 1-66

Bousfield, E. L.; Hoover, P. M. (1997) The amphipod superfamily Corophioidea on the Pacific coast of North America. Part V. Family Corophiidae: Corophiinae, new subfamily. Systematics and distributional ecology., Amphipacifica 2(3): 67-139

Bousfield, E.L. (1973) <missing title>, Comstock Publishing Associates, Ithaca, NY. Pp. <missing location>

California Department of Fish and Wildlife (2014) Introduced Aquatic Species in California Bays and Harbors, 2011 Survey, California Department of Fish and Wildlife, Sacramento CA. Pp. 1-36

Chapman, John W. 2005 Aoridae. <missing URL>



Chapman, John W. (2007) The Light and Smith Manual: Intertidal invertebrates from Central California to Oregon (4th edition), University of California Press, Berkeley CA. Pp. 545-611

Cohen, Andrew N. and 10 authors (2005) <missing title>, San Francisco Estuary Institute, Oakland CA. Pp. <missing location>

Cohen, Andrew N. and 12 authors (2002) Project report for the Southern California exotics expedition 2000: a rapid assessment survey of exotic species in sheltered coastal waters., In: (Eds.) . , Sacramento CA. Pp. 1-23

Crawford, G. I. (1937) A review of the amphipod genus Corophium, with notes on the British species., Journal of the Marine Biological Association of the United Kingdom 21: 589-630

Foss, Stephen (2009) <missing title>, California Department of Fish and Game, Sacramento CA. Pp. <missing location>

Foss, Stephen (2011) <missing title>, California Department of Fish and Game, Office of Spill Prevention and Response, Sacramento. Pp. 54

Hinton, Susan A. (1998) <missing title>, Northwest Fisheries Science Center, Seattle WA. Pp. 1-5

Myers, Alan A. (1998) A cladistic and biogeographic analysis of the Aorinae subfamily nov., Crustaceana Supplement(13): 167-192

Ranasinghe, J. Ananda and 6 authors. (2005) The prevalence of non-indigenous species in southern California embayments and their effects on benthic macroinvertebrate communities, Biological Invasions 7: 679-686

Ruiz, Gregory M.; Geller, Jonathan (2018) Spatial and temporal analysis of marine invasions in California, Part II: Humboldt Bay, Marina del Re, Port Hueneme, and San Francisco Bay, Smithsonian Environmental Research Center & Moss Landing Laboratories, Edgewater MD, Moss Landing CA. Pp. <missing location>

Ruiz, Gregory; Geller, Jonathan (2021) Spatial and temporal analysis of marine invasions: supplemental studies to evaluate detection through quantitative and molecular methodologies, Marine Invasive Species Program, California Department of Fish and Wildlife, Sacramento CA. Pp. 153 ppl.

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