Condition and Resources

Distribution of the invasive freshwater shrimp Palaemon sinensis (Sollaud, 1911) in rivers of Hiroshima Prefecture, western Japan

Hidetoshi Saito, Aiko Yamasaki, Junpei Watanabe and Koichiro Kawai, Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima 739-8528, Japan Faculty of Applied Biological Science, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima 739-8528, Japan

                                     

Gambar 1. Palaemon sinensis

The freshwater palaemonid shrimp, Palaemon sinensis was imported into Japan from China as live fishing bait, In that study, field research was conducted to confirm the distribution of this invasive shrimp in eight rivers in Hiroshima Prefecture, western Japan. A longitudinal distribution analysis showed that P. sinensis occurred in the lower reaches, whereas P. paucidens showed a wider distribution from the upper to the lower reaches. Palaemon sinensis occurred in a narrow range of stream velocity (0–2 cm/s) compared with that of P. paucidens (0–18 cm/s). P. sinensis density was negatively correlated with river velocity, indicating that this shrimp prefers a lentic water environment. Palaemonetes sinensis (see Ashelby et al. 2012; De Grave and Ashelby 2013), are supplied under the trade name “Shirasa ebi” in western Japan as live fishing bait for rockfish. They examined and identified both species based on the difference in carapace colour pattern (Imai and Oonuki 2014). Water quality data at the sampling sites where P. sinensis was found, were 0 for salinity, 6.63–10.03 mg/l for DO, 6.0–12.5 ms/m for electrical conductivity, and 0–2 cm/S for velocity Water quality data at the sampling sites where P. Paucidens was found were 0–1.5 for salinity, 6.48–9.27 mg/l for Do, 4.0–224.1 ms/m for electrical conductivity, and 0–18 cm/S for velocity. In the last three rivers, it was found in lower reaches at 3–9 m of altitude and 2.0–4.8 km from the river mouth. Their results show that P. sinensis has a narrow range of stream velocity (0–2 cm/s) compared with that of P. paucidens (0–18 cm/s). Stepwise multiple regression revealed that the density of P.sinensis was negatively correlated with water velocity. P. sinensis reportedly occurs in lentic downstream environments of Far East Russia (Kawai and Nakata 2011). Caridean shrimp species that inhabit lotic environments are classified into two types based on their methods of adaptation, i.e., amphidromous shrimp species that metamorphose in a marine environment and lay smaller eggs,

and landlocked shrimp that lead their entire life history in a river and lay fewer large eggs (Shokita 1979). C.leucosticta and M. nipponense were collected in the tidally influenced areas and/or adjacent freshwater area. These shrimp are considered to be diadromous and migrate between the river and sea to spawn (Armada et al. 1993; Kawai and Nakata 2011; Saito et al. 2012; Toyota and Seki 2014). In fresh water areas, landlocked shrimp, such as P. sinensis, P. paucidensand Neocaridina spp. were distributed and lay fewer large eggs (Shokita 1979; Shih and Cai 2007; Oonuki et al. 2010; Toyota and Seki 2014). These shrimp are important components of aquatic ecosystems, playing a key role at intermediate tropic levels, as consumers of algae, detritus and small insects, and as prey of many fishes (Kawai and Nakata 2011; Puspitasari 2013).

Resources : Water

Condition : Water quality of river (salinity, DO, electricity conductivity, velocity)

Performance: methods of adaptation, i.e., amphidromous shrimp species that metamorphose in a marine environment and lay smaller eggs, and landlocked shrimp that lead their entire life history in a river and lay fewer large eggs

REFERENCES

Kawai T, Nakata N (2011) Shrimps, Crabs and Crayfishes: Conservation and Biology of Freshwater Crustaceans. Seibutsukenkyusha, Tokyo, 460 pp (in Japanese)

Oonuki T, Suzuki N, Akiyama N (2010) Annual reproductive cycle of the female Palaemonetes sinensisrecorded for the first time in a pond of Hamamatsu City, Shizuoka Prefecture, Japan. Aquaculture Science 58: 509–516 (in Japanese with English abstract)

Shih HT, Cai Y (2007) Two new species of the land-locked freshwater shrimps genus, NeocaridinaKubo, 1938 (Decapoda: Caridea: Atyidae), from Taiwan, with notes on speciation on the island. Zoological Studies46: 680–694

Shokita S (1979) The distribution and speciation of the inland water shrimps and prawns from the Ryukyu Islands-II. Bulletin of the College of Science, University of the Ryukyus28: 193–287 (in Japanese with English abstract)

Toyota K, Seki S (2014) Shrimp & Crab. Seibundo-Shinkosha, Tokyo, 255 pp (in Japanese)