The saltmarsh topminnow (Fundulus jenkinsi) is federally listed as a Species of Concern due to a its rarity, impacts from human activities, and lack of information on its biology and ecology. From 2007 through 2008, we used Breder traps to fish the marsh edge on a falling tide in four regions from Louisiana through the Florida panhandle during winter, spring, and summer periods. Out of 2,108 Breder traps deployed, 661 F. jenkinsi were collected as far east as Escambia Bay, Florida, with Weeks Bay, National Estuarine Research Reserve (NERR), Alabama, yielding the highest F. jenkinsi abundance. Principal component analysis (PCA) was used to ordinate physical-chemical data into two meaningful components: a geomorphic axis (water depth, bank slope, and plant stem density) and a seasonal/spatial axis of species occurrence (water temperature, salinity, and turbidity). PCA showed a higher mean catch-per-unit-effort (CPUE) in environments comprised of low to moderate stem density (<25 stems/0.25 m −2 ), depth (<25 cm), bank slope (<15°), turbidity (<30 NTU), and salinity (<16) coupled with spring and early summer water temperatures (>15°C). F. jenkinsi CPUE was significantly higher in Spartina cynosuroides marsh edge compared with five other habitat types, even though it was one of the least sampled habitats. This species appears to be collected more frequently and in higher CPUE in small dendritic creeks off of main channels than suggested by our previous work in main channel edge habitat. This suggests that small creeks are important vectors for marsh access and supports the value of the dendritic nature of salt marshes to marsh residents.

AbstrAct:One ecological service that oyster reefs provide is stabilization of shorelines through reduced wave energy and erosion from boat traffic, storms, and predominant wind direction. Additionally, increasing sedimentation can enhance the growth of emergent marsh vegetation which further stabilizes unconsolidated sediments. A 21 mo study of constructed (with only 30-35% coverage) and natural oyster reefs in 3 bayous in the Grand Bay National Estuarine Research Reserve (NERR) suggested constructed reefs benefit this retrograding deltaic ecosystem. The marsh edge adjacent to all constructed reefs was less eroded (mean = 0.043 m) than edges adjacent to natural reefs (mean = 0.728 m), although all natural and constructed sites, regardless of bayou, illustrated large variations in marsh edge growth. The marsh edge in constructed sites in one bayou retreated more than in the other bayous, most likely due to its coarser sediments, greater boat traffic, and its apparent higher energy location within the landscape. By the end of this study, the ecological function of constructed oyster reefs in all bayous, as measured by marsh edge erosion reduction, was equivalent or exceeded the function in nearby natural oyster reefs. The physical structure of the reef further served to reduce erosion and marsh loss and this approach may be useful for management of a retrograding deltaic estuarine ecosystem like the Grand Bay NERR.

Fundulus jenkinsi is a state and federally listed Species of Concern because it is rare and is threatened by human activities, and ecological information is lacking. Fish collected from Louisiana, Mississippi, Alabama, and Florida, USA, during winter, spring, and summer were evaluated for selected habitat-linked reproductive and trophic metrics. Mouth-gape-weight relationships increased with standard length (SL) but did not differ by gender. An exposed genital papilla, an anal sheath, and an elongated posterior anal ray separated mature males from females in 86.7% of the fish examined (year round), and adding vertical bars and dark dorsal pigmentation increased this percentage to 96.7% (seasonal). There was a clear season-size spawning relationship, whereby fish < 20 mm SL were immature, and ovary phases and oocyte stages suggested that spawning initiated in spring/early summer. Diet did not vary by size-class but did vary seasonally. Summer diets were most similar to each other compared to other seasons, with prey consisting of arachnids, crab zoea, dipterans, amphipods, hymenopterans, and hemipterans. Aquatic prey size classes shifted with increased fish size and mouth gape, which allowed for larger prey to be consumed. Smaller-bodied terrestrial prey were consistently consumed regardless of fish body size. Overall, reproduction and diet are strongly linked with mid-and high salt marsh access. These data highlight small, interconnected intertidal creeks embedded within salt marshes as access points for reproduction and foraging and suggest that 'dendritic' complexes of intertidal creeks should be a focus in conservation planning efforts, and that efforts to restore tidal marsh habitat should attempt to mimic these naturally occurring complexes.