Invasion HistoryFirst Non-native North American Tidal Record: 1990
First Non-native West Coast Tidal Record:
First Non-native East/Gulf Coast Tidal Record: 1990
General Invasion History:
The free-living cyclopoid copepod Apocyclops dengizicus was described from Kazakhstan in 1900, and ranges from North Africa (Libya, Egypt) through Central Asia (Iran, Iraq, Uzbekistan, the Caspian Sea), East Asia (India, Malaysia) and Australia (Mirabdullayev and Stuge 1998; Reid et al. 2002). Within this range, A. dengizicus prefers habitats typical for its genus, including inland saline lakes in arid regions, closed brackish lagoons, and occasionally, tidal marshes. Although they tolerate wide ranges of salinity, Apocyclops spp. do not normally occur in marine plankton (Reid et al. 2002; Reid, personal communication, 2003). Reports of this species from the Salton Sea, California are based on records of the native A. dimorphus (Reid et al. 2002).
North American Invasion History:
Invasion History on the East Coast:
Only three verified specimens of Apocyclops dengizicus are known from North America, all from the Chesapeake Bay region. In 1990, two stage V copepodites (last molt before adulthood) were collected from driven wells in tidal marshes on Wye Island, Queen Annes County, Maryland, on the Eastern Shore of the Chesapeake Bay. In 1998 an adult specimen was collected from a highly atypical habitat for this genus, the leaves of Sarracenia purpurea (Purple Pitcherplant) in boggy land near the North Anna River in Caroline County, Virginia, about ~10-20 km above tidewater. The vase-like leaves of the carnivorous pitcherplant support a community of small invertebrates and microbes, many unique to this habitat, which digest trapped insects (Reid et al. 2002). Reid et al. (2002) suggest that the individual in the pitcher plant may have been derived from populations in small, isolated, brackish water-bodies around the Chesapeake Bay, and that this species is likely to disperse rapidly along the Atlantic Coast. They suggest ballast water as the likeliest means of introduction. However, transport with ornamental aquatic plants or fish seems possible, since copepods of this genus can breed in fresh waters (Reid, personal communication 2003).
Since we know of only three specimens from the region at this time, we do not know whether populations are established, but the occurrence in a pitcher plant suggests that source populations might occur near the Chesapeake Bay and other North American estuaries.
Adult Apocyclops dengizicus have a typical cyclopoid body form, with a shield-like cephalothorax (head-carapace). The first leg-bearing thoracic segment is fused with the head, followed by three tapered thoracic segments, giving the animal a club-shaped appearance. The cephalothorax and urosome are finely sculptured and covered with tiny pits.
In adult females, the urosome is tapered and cylindrical, consisting of five segments, including a swollen 2nd (genital segment) and three posterior segments. The 5th pair of legs occurs on the 1st urosome segment and consists of single segments, each bearing a single seta and a short, thick spine. The caudal rami are ~4.5X longer than broad. The antennule has 11 segments, all bearing setae. The 3rd segment has 10 setae. Swimming legs P1-P4 are biramous, with each ramus consisting of two segments. The medial margins of the basipodites of P1-P4 have the medial margin of the basipodite extended into long spiniform structures. The terminal spine of the endopodite of P4 is about as long as the terminal segment. Females are 0.95-1.35 mm long and carry paired egg sacs.
Adult male A. dengizicus have symmetrical antennules with 14 segments, strongly hinged between segments 7 and 8, and segments 11 and 12. The urosome consists of six segments and the caudal rami are 5.5-6.5X as long as wide. Males are 0.78-1.08 mm long. Description based on Valderhaug et al. 1979, Mirabdullayev and Stuge 1998, and Reid 2002.
Larval development of A. dengizicus has been described by Valderhaug et al. (1979).
Potentially Misidentified Species
Found in saline lakes and coastal fresh to saline pools in the Salton Sea, California; Haiti; Mexico; and Texas.
Found in saline lakes, coastal fresh to saline pools, and Spartina marshes from Massachusetts to Florida, Bermuda, West Indies, and Mexico.
Found in ponds and Spartina marshes from Massachusetts to Delaware.
Planktonic cyclopoid copepods mate in the water column. Males use their modified antenules to grasp the female and transfer spermatophores to the female's genital segment. Females carry eggs in two symmetrical clusters under the abdomen (Barnes 1983). Eggs hatch into nauplii which go through six stages. The first stage, NI, has 3 pairs of appendages and is unsegmented - each molt has additional appendages and/or more differentiation of segments. The sixth stage (NVI) molts into a first copepodite stage (CI), with the basic form of the adult, and fully differentiated feeding structures, but with only two pairs of swimming legs, and only one urosomal segment. The copepod goes through five additional molts, with increasing numbers of swimming legs, urosomal segments, and sexual differentiation. Development for females takes 6.8-8.0 days at 25-28 C, while males mature about a day earlier. The sixth (CVI) stage is the male or female adult (Valderhaug et al. 1979; Barnes 1983).
Apocyclops dengizicus, like other copepods of its genus, is characteristic of saline inland waters, and isolated coastal pools, but rarely occurs in open estuarine waters. It is capable of completing its life cycle in freshwater (Mirabdullayev and Stuge 1998; Reid 2002). The only adult record from North America is from an anomalous habitat - the water in the leaf of a Pitcher-plant (Sarracenia purpurea), which usually supports a specailized community of adapted invertebrates (Reid 2002). Adult and juvenile cyclopoid copepods feed raptorially, and may be carnivorous or omnivorous, feeding on algae, ciliates, rotifers, and copepod nauplii (Barnes 1983).
Tolerances and Life History Parameters
|Minimum Salinity (‰)||0||Apocyclops dengizicus has been found in freshwater habitats (Reid 2002).|
|Maximum Salinity (‰)||26||Salinity- Copepods of the genus Apocyclops typically occur in saline inland lakes in arid regions, and in coastal lagoons. In the literature which we have seen, so far, the highest reported salinity for A. dengizicus is 26 g/L, from Lake Tengiz, in central Kazakhstan, where the salt composition probably differs considerably from seawater. The closely related A. dimorphus tolerates a range of 0.5-68 g/l and survives for 60 days at salinites as high as 107 g/l (Dexter 1993, cited by Reid et al. 2002).|
|Minimum Length (mm)||0.8||Males are 0.78-1.08 mm long (Mirabdullayev and Stuge 1998)|
|Maximum Length (mm)||1.4||Females from central Asia range 0.95-1.35 mm (Mirabdullayev and Stuge 1998).|
|Broad Temperature Range||None||Warm temperate-Tropical|
|Broad Salinity Range||None||Nontidal Limnetic-Polyhaline|
General ImpactsApocyclops dengizicus is widely reared in Asia as a food organism for larvae and juveniles of aquaculture shrimps and fishes. However, we do not know if it has been imported into North America for this purpose. It's establishment in North America is uncertain, and it has no known impacts.
Regional Distribution Map
|Bioregion||Region Name||Year||Invasion Status||Population Status|
ReferencesMirabdullayev, Iskandar M.; Stuge, Tatiana S. (1998) Redescription of Apocyclops dengizicus from Central Asia., Spixiana 211(2): 173-178
Mohamed. Hanaa Hussain; Salman, Salman Daood; bdullah, Abdullah, Abdul Aziz Mahmood (2006) Some aspects of the biology of two copepods: Apocyclops dengizicus and Mesocyclops isabellae from a pool in Garmat-Alli, Basrah, Iraq, Turkish Journal of Fisheries and Aquatic Sciences 8: 239-247
Reid, Janet; Hamilton, Robert IV; Duffield, Richard M. (2002) First confirmed New World record of Apocyclops dengizicus (Lepeshkin), with a key to the species of Apocyclops in North America and the Caribbean region (Crustacea: Copepoda: Cyclopidae)., Jeffersoniana 10: 1-25
Valderhaug, Veronica Alvarez; Kewalramani, H. G. (1979) Larval development of Apocyclops dengizicus Lepeshkin (Copepoda), Crustaceana 36(1): 1-8