January Fish of the Month: Bluenose Shiner Pteronotropis welaka

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January Fish of the Month: Bluenose Shiner Pteronotropis welaka

Dr. Geoffrey Smith

NWFSC Biology Instructor

 

The Bluenose Shiner is a small (maximum size of about 2 inches) freshwater species that is endemic to a few of the river drainages in the southeastern US. Endemic species, are organisms that have a very limited natural distribution range. In general, the greater the level of endemism (in other words the smaller the natural distribution range) the greater the potential risk for extinction of a particular species, because any impact to this small area could eradicate the entire population with no other sources to repopulate it. The Bluenose Shiner inhabits backwaters, swamps, and spring runs of larger rivers typically near aquatic vegetation in deeper pools of water. They have been documented in river drainages between the Pearl River in Mississippi and Louisiana eastward to below the fall line of the Apalachicola River. There is also a separate population that exists in the St. Johns River in Florida, with no individuals being documented anywhere between the St. Johns and Apalachicola Rivers (Figure 1). The species name, welaka, is derived from the city of Welaka on the St. Johns River where this species was first documented. In Florida, Bluenose Shiners have been documented in drainages of the Escambia, Blackwater, Yellow, Choctawhatchee, Apalachicola, and St. Johns Rivers.

The common name, bluenose, is based on the bright blue snout that males of this species exhibit during the spawning season. Breeding males also have a nearly black body and dorsal fin with a bluish colored stripe down the side of the body, iridescent patches, and bright red areas near the tail. Non-breeding males and females have a more typical shiner coloration of tan to gray or silver with a black stripe and black spot near the tail. The bright colors of the breeding males have made this species popular with some groups of aquarists, however, this species is listed as threatened in Florida and their harvest is prohibited.

As mentioned previously, the fact that this is an endemic species with a small natural distribution put it at risk for population declines and possible extinction if there are impacts to the limited areas where this species lives. Besides harvest, some potential threats that have been noted are the damming of rivers to form reservoirs (reduces water flow and eliminates habitat: floods habitat above the dam and drains habitat below the dam), increased nutrient and sediment inputs into rivers (algae blooms and lower water clarity leading to a loss of aquatic vegetation needed by this species), and non-native species (such as non-native aquatic plants that outcompete native aquatic plant species and non-native snails that overgraze native aquatic vegetation).

Figure 1: Distribution map of Bluenose Shiner (fishmap.org).

Figure 2: A breeding male (top), non-breeding male (middle), and female (bottom) Bluenose Shiner (floridamuseum.ufl.edu: top photo-Howard Jelks, USGS, middle and bottom photos-Zachary Randall, UF.

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