Speckled pocketbook is a freshwater mussel endemic to Little Red River watershed in the Boston Mountains ecoregion of Arkansas. The species historical distribution likely included much of the main stem Little Red River and its four forks, Archey, Devil’s, Middle, and South, as well as Big Creek, that converges at the Little Red River’s north bank near Pangburn, Arkansas. Speckled pocketbook was extirpated from the main stem Little Red River with the construction of Greers Ferry Lake, which also inundated the lower reaches of the Middle, South and Devil’s forks. Populations in the Middle and South forks and Big Creek are declining. There is an active propagation effort ongoing to restore the species within its current range, as well as numerous other conservation efforts in the upper Little Red River watershed by our conservation partners.
Speckled pocketbook remains threatened by a variety of land use practices that contribute sediment, nutrients and other pollutants to the rivers, and which may be exacerbated by. Speckled pocketbook mussel still expereince threats throughout their range and recent population declines underscore the vulnerability of each isolated population to potential catastrophic events.
Suitable habitat occurs in pools and runs with small to large boulders which have some accumulation of sand or gravel. Individuals are typically located in crevices between boulders or underneath perched boulders.
A natural body of running water.
Food items for mussels include algae, bacteria, detritus and microscopic animals. Adult mussels are filter feeders and generally orient themselves on or near the substrate surface to take in food and oxygen from the water column. Juveniles typically burrow completely beneath the substrate surface and are pedal, or foot feeders, until they fully develop structures for filter feeding. Foot feeders bring food particles inside their shell for ingestion that adhere to their foot, while it is extended outside the shell.
Food items for mussels include algae, bacteria, detritus, and microscopic animals. Adult mussels are filter feeders and generally orient themselves on or near the substrate surface to take in food and oxygen from the water column. Juveniles typically burrow completely beneath the substrate surface and are pedal (foot) feeders (bringing food particles inside the shell for ingestion that adhere to the foot while it is extended outside the shell) until the structures for filter feeding are more fully developed.
The shell is elliptical in shape. This species is sexually dimorphic, with the female being more rounded on the posterior end.
The shell is elliptical, dark yellow or brown with chevron-like spotes, and rays that are chain-like.
Male mussels release sperm into the water column, where females draw it in through their siphons during feeding and respiration. Mussel density and water flow conditions influence fertilization success. Females retain eggs in their gills until they develop into mature larvae called glochidia. The glochidia of most freshwater mussel species, including speckled pocketbook, have a parasitic stage during which they must attach to the gills, fins or skin of a fish to transform into a juvenile mussel. Depending on the mussel species, females release glochidia either separately, in masses known as conglutinates, meaning gelatinous or jelly–like, or in one large mass known as a super-conglutinate. The duration of the parasitic stage varies by mussel species, water temperature and perhaps host fish species. When the transformation is complete, the juvenile mussels drop from their fish host and sink to the stream bottom where, given suitable conditions, they grow and mature into adults.
Speckled pocketbook glochidia are an obligate parasite on fish in the sunfish family (Centrarchidae). Primary hosts include green sunfish (Lepomis cyanellus), smallmouth bass (Micropterus dolomieu), largemouth bass (Micropterus salmoides) and spotted bass (Micropterus punctulatus). Females are gravid, or carrying eggs, as early as June through August, and generally release glochidia in late winter, from February through Spring, or April and May.
Unknown, but generally less than 15 years.
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