RE: NANFA-- Freshwater Shrimp Info Macrobrachium ohione

Hoover, Jan J ERDC-EL-MS (HOOVERJ_at_wes.army.mil)
Tue, 31 Dec 2002 14:59:38 -0600

>>>Anyone out there have any info, references or leads on the freshwater
shrimp, Macrobrachium ohione ? This is not the tiny grass shrimp, but a
larger, rarer species that lives/lived in the Ohio River and elswhere. I
am looking for info on abundance in Ohio and possible collecting sites.<<<

Mark -

I do not know about Ohio, but Macrobrachium is abundant in the lower
Mississippi basin, and I have been keeping some recently.

We see it as common "by-catch" when trawling in the Mississippi river and
tribs. We rarely get it over gravel, but frequently over sand in a very
wide range of depths. To collect them, one of the small,
commercially-produced trawls for shrimp or baitfish can be pulled behind an
open boat (we deploy the net off the bow and then back down the river). The
shrimp are extremely hardy and have high survivorship even after being
collected this way. If you do not have ready access to a boat (or large,
sandy bottom river), you might be able to have a commercial fisherman save
them for you. A co-worker of mine (an invertebratologist) says that he
frequently sees them in dipnet samples from water as shallow as 3 ft.

This past Sept, I kept a group of 21 in small buckets (no aeration for
several hours) and then set them up in a couple of 5 1/2 gal tanks with foam
filters. They ate everything they were offered (e.g., Spirulina, flakes,
frozen brine shrimp, pellets) but bloodworms were eaten with gusto. After a
week, they developed a surprising range of colors: clear to dark
green-brown; a few were cobalt blue.

Jumping was a problem. My only other problem was cannibalism - after a
shrimp shed its skin (usually late at night), the others would eat his
walking legs down to nubs rendering him helpless. Spreading the shrimp out
among tanks and providing PVC as hiding places helped, but did not stop the
attacks. As a result I had gradual attrition. The last shrimp died eight
months after it was caught (it was an adult when captured).

There is a very nice write-up on the species including detailed life history
data and a map with some localities in Larry Page's excellent 1985
publication "The Crayfishes and Shrimps (Decapoda) of Illinois," Bull. Ill.
Nat. Hist. Surv. 33(4): 335-448.

- Jan

P.S. One 84 mm female from Chester, IL (birthplace of Popeye) had 8000
eggs.
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