In 2017 researchers from Auburn University published a paper looking at the impact of development in Baldwin County on the streams that feed the lower Perdido Bay system.  In this study they also included streams from the Florida side of Perdido Bay.  They divided their study sites into rural and urban based on the number of buildings/kilometer and area of forested land.  They compared sediments, water quality, and biology in the streams of these two study areas to determine impacts, if any.

One thing I noticed when they did their presentation was the absence of the longnose killifish (Fundulus similis) from all urban creeks.  And that it was only found in rural creeks with close association with higher saline sites.  Though studies suggests that the longnose killifish can tolerate a wide range of salinities, I was still curious whether this fish could be used as an indicator for urban runoff issues.  After consultation with Auburn, we decided to replicate their study at other locations on our side of the bay but focusing only on presence absence of the longnose killifish.

Auburn study was conducted once a season; this was due to the distance they had to travel – but we wanted to replicate it so we would sample once a season.  Five baited minnow traps were placed in creeks that fed the estuary on mornings when the tide was falling.  Soak time would be four hours.  Our project replicated all except we would only use three traps / creek.  We selected four creeks in the western side of Escambia County to monitor.  These include: Bayou Garcon (feeding Perdido Bay), Kees Bayou (feeding the Intracoastal Waterway), Big Lagoon State Park (the creek leaving the Grand Lagoon neighborhood feeding into the state park and eventually into Big Lagoon), and Soldiers Creek (feeding into Bayou Grande).  Local volunteers were trained to conduct these surveys and identify the fish captured.  These surveys are to be conducted during the four seasons in 2022 and 2023.  Below are the results of the survey to date is below.

Discussion

Bayou Garcon

This location is dominated by needlerush marsh, muddy bottom, and salinities ranged between 14-0 ppt.  It is a good location to determine presence/absence but has not had a lot of development directly on the waterway in a few years.  There is development occurring within its watershed.  This site captured 10 fish in 2022 but they were all pinfish with some young blue crabs captured. – no longnose killifish.  All fish were returned.  Due to difficulty of getting the boat into this site (extreme tides) it will not be sampled in 2023.

Kees Bayou

This location is also a needlerush marsh but has a sandier bottom and higher salinity (reported at 13 ±1 ppt each season sampled).  There is development on the waterway with new development occurring within its watershed.  This site captured the most fish (n=49).  Most were pinfish, other estuarine species, young blue crabs, but no longnose killifish present.  All fish were returned.

Grand Lagoon / Big Lagoon SP

This location is a creek that leaves the Grand Lagoon neighborhood and feeds into the northeast end of the state park.  It then enters Big Lagoon.  The creek itself has development on the waterway and much discharge from the neighborhood.  The vegetation is more freshwater in species composition and the salinity was never above 2 ppt. (there was no sampling conduct during the fall).  This location captured six fish, but all were freshwater species (as expected).  Two freshwater species of turtles were also captured suggesting this is a freshwater creek and would not expect longnose killifish here.  All fish and turtles were returned.

Soldiers Creek

This location is a needlerush marsh with some bulrush present as well – suggesting a lower salinity.  It is located near Gulf Beach Highway and has development on the waterway.  It eventually feeds into Bayou Grande.  The salinity at this site was never above 4 ppt. suggesting a more freshwater system.  Only three fish were captured at this location, and all were freshwater species – no longnose were present.  A turtle was also captured at this site further suggesting a freshwater system.

Comments

Based on the 2022 results, the sites at Bayou Garcon and Kees Bayou should support longnose killifish; they are not expected to be found at the Big Lagoon SP/Soldiers Creek sites.  One could argue that the Big Lagoon SP/Soldiers Creek once supported this species before development occurred decades ago.  There is certainly plenty of stormwater influencing both.  We will continue monitoring in 2023 and report again next year.

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