Two species of shrimps occur in Arkansas; they include the Ohio shrimp, Macrobrachium ohione (Smith) and the Mississippi grass shrimp, Palaemonetes kadiakensis Rathbun. The present survey is based on collections made between 1974 and 2008 with additional supplemental data from museum specimens to document the overall distribution of the 2 species. Our survey found a total of only 42 specimens of M. ohione from 6 localities (2 counties) in Arkansas, all taken from the Mississippi River. Specimens were seined over sandy substrates in 0.6-0.9 m of water without vegetation. A 1914 museum collection of 5 individual M. ohione is the only known occurrence of M. ohione from Phillips County. All other specimens were taken between 1974-1975 near the US 82 bridge (Chicot County). It appears that M. ohione is a relatively rare shrimp in Arkansas. Since specimens were documented from a single drainage system (Mississippi River) in only 2 counties, we recommend a “threatened” conservation status of M. ohione in Arkansas because of this restricted distributional range. However, P. kadiakensis is relatively abundant in Arkansas. This shrimp had previously been reported from 10 counties of the state. Over 3,400 specimens of P. kadiakensis were documented during this study from various sites in 49 counties and most were released upon capture. Grass shrimp were commonly found in sluggish backwater regions of streams especially preferring heavily vegetated lentic areas of pool regions. Mississippi grass shrimp have remained abundant and widespread in occurrence for the past 35 years. The Nature Conservancy lists populations of P. kadiakensis as secure (G5) in rounded global status. Indeed, Mississippi grass shrimp populations in Arkansas are also secure and in no need of special protection.
Robison, H. W. and McAllister, C. T.
"Geographic Distribution and Life History Aspects of the Freshwater Shrimps, Macrobranchium ohione and Palaemonetes kadiakensis (Decapoda: Palaemonidae),
Journal of the Arkansas Academy of Science: Vol. 65
, Article 15.
Available at: http://scholarworks.uark.edu/jaas/vol65/iss1/15