Geology topics

Frank Jordan

Publications and source records attributed to Frank Jordan.

6 recordsLinked to original sources

USGS2020

Discovery of a reproducing wild population of the swamp eel Amphipnous cuchia (Hamilton, 1822) in North America

We report discovery of an established population of the Asian swamp eel Amphipnous cuchia (Hamilton, 1822) in Bayou St. John, an urban waterway in New Orleans, Louisiana, USA. This fish, commonly referred to as cuchia (kuchia), is a member of the family Synbranchidae and is native to southern and southeastern Asia. Recently-used synonyms include Monopterus cuchia and Ophichthys cuchia . We collected both adult and young-of-year cuchia from dense mats of littoral vegetation at several locations in Bayou St. John. Presence of multiple age and size classes is the first documented evidence of reproduction of this species outside of its native range. Establishment of this air-breathing, burrowing, salt-tolerant, opportunistic predator is of concern given that Bayou St. John is a tributary of Lake Pontchartrain, which provides a direct pathway for dispersal into the Mississippi River basin and coastal wetlands of the Gulf of Mexico.

Louisiana↗

USGS2016

Response of imperiled Okaloosa darters to stream restoration

The Okaloosa Darter Etheostoma okaloosae is a small percid endemic to six stream drainages in northwestern Florida. The U.S. Fish and Wildlife Service listed Okaloosa Darters as endangered in 1973 and downlisted them to threatened in 2011 because of habitat improvements and increasing abundance across much of their geographic range. Delisting is possible if remaining recovery criteria are met, including restoration of degraded stream reaches. Impounded reaches of Anderson Branch, Mill Creek, and Toms Creek were restored by removing impediments to water ﬂow, draining impoundments, and reconstructing stream reaches. Restorations of Anderson Branch and Mill Creek were designed to rehabilitate populations of Okaloosa Darters without signiﬁcantly affecting popular recreational activities at these locations. Restorations were evaluated from 2007 to 2013 by comparing counts of Okaloosa Darters and the composition of microhabitats in restored and nearby undisturbed reference sites. Okaloosa Darters were absent from degraded stream reaches at the beginning of the study, but they rapidly colonized once restorations were completed. Counts of Okaloosa Darters in reference and restoration sites in Anderson Branch were similar by the end of the study, whereas counts in restoration sites were signiﬁcantly lower than nearby reference sites in Mill and Toms creeks. Restoration sites tended to have lower coverage of sand and root and higher coverage of macrophytes. As riparian vegetation surrounding restoration sites matures to a closed canopy that reduces excessive growth of macrophytes, stream microhabitats and numbers of darters will probably become similar to reference sites. Restoration of degraded stream sites increased abundance and distribution of Okaloosa Darters and reconnected formerly isolated upstream and downstream populations. These projects demonstrated that restoration is a useful conservation tool for imperiled ﬁshes such as Okaloosa Darters and can be undertaken without interfering with popular recreational activities.

Florida↗

USGS2013

Movement and longevity of imperiled Okaloosa Darters (Etheostoma okaloosae)

Movement and longevity studies inform management and conservation plans for imperiled organisms. We used a mark–recapture study to reveal information about these key biological characteristics for imperiled Okaloosa Darters (Etheostoma okaloosae). Okaloosa Darters were captured from 20 m reaches at six separate streams, marked with VIE on the left or right dorsum according to the side of the stream from which they were captured, and released on the same side where they were captured. Okaloosa Darters were recounted (but not recaptured) at 24 h and one month, and then recaptured once per year for the following eight years. During the final recapture year, we measured standard length of all Okaloosa Darters and constructed length frequency distributions to identify distinct cohorts. We found that significant numbers of Okaloosa Darters remained within their 20 m reaches after 24 h (31%), one month (45%), and one year (22%) and rarely crossed open, sandy stream channels from one side to the other. Our recapture data and length frequency distributions indicate that Okaloosa Darters live longer than the 2–3 years suggested by previous authors. One of our recaptured fish was at least eight years old, making Okaloosa Darters the most long-lived etheostomine.

Copeia↗

USGS2011

Population genetic structure and conservation genetics of threatened Okaloosa darters (Etheostoma okaloosae)

Imperiled Okaloosa darters ( Etheostoma okaloosae ) are small, benthic fish limited to six streams that flow into three bayous of Choctawhatchee Bay in northwest Florida, USA. We analyzed the complete mitochondrial cytochrome b gene and 10 nuclear microsatellite loci for 255 and 273 Okaloosa darters, respectively. Bayesian clustering analyses and AMOVA reflect congruent population genetic structure in both mitochondrial and microsatellite DNA. This structure reveals historical isolation of Okaloosa darter streams nested within bayous. Most of the six streams appear to have exchanged migrants though they remain genetically distinct. The U.S. Fish and Wildlife Service recently reclassified Okaloosa darters from endangered to threatened status. Our genetic data support the reclassification of Okaloosa darter Evolutionary Significant Units (ESUs) in the larger Tom’s, Turkey, and Rocky creeks from endangered to threatened status. However, the three smaller drainages (Mill, Swift, and Turkey Bolton creeks) remain at risk due to their small population sizes and anthropogenic pressures on remaining habitat. Natural resource managers now have the evolutionary information to guide recovery actions within and among drainages throughout the range of the Okaloosa darter.

Florida↗

USGS2011

Weapons testing and endangered fish coexist in Florida

Okaloosa darters ( Etheostoma okaloosae ) are small fish found only in a few streams in the Florida panhandle. This species has been listed since 1973 as endangered due to habitat alteration resulting from erosion, the potential competition from brown darters ( E. edwini ), and a limited geographic distribution. In recent years, however, Okaloosa darters have benefited from improved resource management and adaptive population monitoring techniques developed collaboratively by the U.S. Fish and Wildlife Service (FWS), U.S. Geological Survey (USGS), Loyola University New Orleans, and Eglin Air Force Base. As a result, the FWS reclassified the Okaloosa darter to the less critical category of threatened in March 2011.

Florida↗

USGS2000

Contrasting patterns of habitat use by prawns and crayfish in a headwater marsh of the St. Johns River, Florida

We compared seasonal patterns of habitat use by the prawn Palaemonetes paludosus and the crayfish Procambarus alleni in Blue Cypress Marsh Conservation Area, Florida. Prawn densities were similar to those found in other oligotrophic wetlands of southern Florida, whereas crayfish densities were much greater than reported previously for other wetlands in the area. Prawns and crayfish had strikingly different patterns of habitat use. Prawn density and biomass were similar in wet prairies and sloughs, whereas crayfish density and biomass were significantly higher in wet prairies. Within habitats, the abundance of prawns and crayfish generally increased with increasing structural complexity and the abundance of crayfish generally decreased with increasing water depth. Differences in risk of predation, frequency of agonistic encounters, food availability, and other factors likely contributed to observed patterns of habitat use. Because of differences in their ability to burrow and avoid concentration into dry-season refugia, prawns and crayfish responded very differently to seasonal variation in hydrologic conditions. Prawn densities were initially low (following a severe drought) and then increased during much of the study period, whereas crayfish densities were relatively stable throughout the study period. Overall, it appears that prawns are more responsive to antecedent hydrologic conditions and crayfish are more responsive to the availability of suitable habitats such as wet prairies.

Florida↗