Panhandle Outdoors Live! at St. Joseph Bay Rescheduled for September 28th

Panhandle Outdoors Live! at St. Joseph Bay Rescheduled for September 28th

The University of Florida/IFAS Extension faculty are reintroducing their acclaimed “Panhandle Outdoors LIVE!” series. Conservation lands and aquatic systems have vulnerabilities and face future threats to their ecological integrity.  Come learn about the important role of these ecosystems.

The St. Joseph Bay and Buffer Preserve Ecosystems are home to some of the one richest concentrations of flora and fauna along the Northern Gulf Coast. This area supports an amazing diversity of fish, aquatic invertebrates, turtles, salt marshes and pine flatwoods uplands.

This one-day educational adventure is based at the St. Joseph Bay State Buffer Preserve near the coastal town of Port. St. Joe, Florida. It includes field tours of the unique coastal uplands and shoreline as well as presentations by area Extension Agents.

Details:

Registration fee is $45.

Meals: breakfast, lunch, drinks & snacks provided (you may bring your own)

Attire: outdoor wear, water shoes, bug spray and sun screen

*if afternoon rain is in forecast, outdoor activities may be switched to the morning schedule

Space is limited! Register now! See below.

Tentative schedule:

All Times Eastern

8:00 – 8:30 am  Welcome! Breakfast & Overview with Ray Bodrey, Gulf County Extension

8:30 – 9:35 am Diamondback Terrapin Ecology, with Rick O’Connor, Escambia County Extension

9:35 – 9:45 am  Q&A

9:45- 10:20 am The Bay Scallop & Habitat, with Ray Bodrey, Gulf County Extension

10:20 – 10:30 am Q&A

10:30 – 10:45 am Break

10:45 – 11:20 am The Hard Structures: Artificial Reefs & Marine Debris, with Scott Jackson, Bay County Extension

11:20 – 11:30 am Q&A

11:30 – 12:05 am The Apalachicola Oyster, Then, Now and What’s Next, with Erik Lovestrand, Franklin County Extension

12:05 – 12:15 pm Q&A

12:15 – 1:00 pm Lunch

1:00 – 2:30 pm Tram Tour of the Buffer Preserve (St. Joseph Bay State Buffer Preserve Staff)

2:30 – 2:40 pm Break

2:40 – 3:20 pm A Walk Among the Black Mangroves (All Extension Agents)

3:20 – 3:30 pm Wrap Up

To attend, you must register for the event at this site: 

https://www.eventbrite.com/e/panhandle-outdoors-live-at-st-joseph-bay-tickets-404236802157

For more information please contact Ray Bodrey at 850-639-3200 or rbodrey@ufl.edu

Finding Rare Animals

Finding Rare Animals

One of the programs I focus on as a Sea Grant Extension Agent in Escambia County is restoring the health of our estuary.  One of the projects in that program is increasing the encounters with estuarine animals that were once common.  Currently I am focused on horseshoe crabs, diamondback terrapins, and bay scallops.  Horseshoe crabs and bay scallops were more common here 50 years ago.  We are not sure how common diamondback terrapins were.  We know they were once very common near Dauphin Island and are often found in the Big Bend area, but along the emerald coast we are not sure.  That said, we would like to see all of them encountered more often.

Horseshoe crabs breeding on the beach.
Photo: Florida Sea Grant

 

There are a variety of reasons why species decline in numbers, but habitat loss is one of the most common.  Water quality declined significantly 50 years ago and certainly played a role in the decline of suitable habitat.  The loss of seagrass certainly played a role in the decline of bay scallops, but overharvesting was an issue as well.  In the Big Bend region to our east, horseshoe crabs are also common in seagrass beds and the decline of that habitat locally may have played a role in the decline of that animal in our bay system.

 

Salt marshes are what terrapins prefer.  We have lost a lot of marsh due to coastal development.  Unfortunately, marshes often exist where we would like houses, marinas, and restaurants.  If the decline of these creatures in our bay is a sign of the declining health of the system, their return could be a sign that things are getting better.

Seagrass beds have declined over the last half century.
Photo: Rick O’Connor

Salt marshes have declined due to impacts from coastal development.
Photo: Molly O’Connor

 

 

 

 

 

 

 

 

 

 

For over 10 years we have been conducting citizen science monitoring programs to monitor the frequency of encounters of these creatures.  All three are here but the increase in encounters has been slow.  An interesting note was the fact that many locals had not heard of two of them.  Very few knew what a horseshoe crab was when I began this project and even fewer had heard of a terrapin.  Scallops are well known from the frequent trips locals make to the Big Bend area to harvest them (the only place in the state where it is legal to do so), but many of those were not aware that they were once harvested here.

 

I am encouraged when locals send me photos of either horseshoe crabs or their molts.  It gives me hope that the animal is on the increase.  Our citizen science project focuses on locating their nesting beaches, which we have not found yet, but it is still encouraging.

Horseshoe crab molts. Photo UF/IFAS Communications

Mississippi Diamondback Terrapin (photo: Molly O’Connor)

 

 

 

 

 

 

 

 

 

Volunteers surveying terrapin nesting beaches do find the turtles and most often sign that they have been nesting.  The 2022 nesting season was particularly busy and, again, a good sign.

 

It is now time to do our annual Scallop Search.  Each year we solicit volunteers to survey a search grid within either Big Lagoon or Santa Rosa Sound.  Over the years the results of these surveys have not been as positive as the other two, but we do find them, and we will continue to search.  If you are interested in participating in this year’s search, we will be conducting them during the last week of July.  You can contact me at the Escambia County Extension Office (850-475-5230 ext.1111) or email roc1@ufl.edu or Chris Verlinde at the Santa Rosa County Extension Office (850-623-3868) or email chrismv@ufl.edu and we can set you up.

Bay scallops need turtle grass to survive.
Photo: UF IFAS

Volunteers participating in the Great Scallop Search.
Photo: Molly O’Connor

 

 

 

 

 

 

 

 

 

Final note…

Each June I camp out west somewhere and each year I look for those hard-to-find animals.  After 10 years of looking for a mountain lion, I saw one this year.  Finding these creatures can happen.  Let’s hope encounters with all three become more common in our bay.

Are Blue-tailed Scorpions Poisonous

Are Blue-tailed Scorpions Poisonous

Well, the answer to this question should be obvious, right? However, when we take a closer look at these interesting creatures, the first impression created by their frightful name will likely evaporate completely. First, scorpions are considered venomous, rather than poisonous (I know, a technicality). They have many predators that eat them with no ill effect so they are not poisonous. Anything that has the ability to deliver a toxin by means of injection is classified as venomous. Next, the name is a true misnomer because the group of animals referred to as blue-tailed scorpions are actually a type of lizard called a skink.

baby broadhead skinks with blue tails

Hatchling broadhead skinks sport a brilliant blue tail but lose this color as they mature. Source: NSF-EID


Scincidae is just one of sixteen families of lizards worldwide but it contains some of the most beautiful species of reptiles. Florida is blessed (yes, blessed) with at least seven species of skinks, with one being divided into five sub-species. Three of the five sub-species of the mole skink have “protected” status under state or federal laws.

Several of our native skinks in the Panhandle are challenging to identify at first glance, particularly during their younger years. The five-lined, southeastern five-lined and broadhead skink are all striped and have blue tails as youngsters, hence the origin of the frightening title for this article. According to folklore, these animals have the ability to deliver a painful sting with their tail. Well, as a lifelong reptile enthusiast, I have had the experience of catching many young, blue-tailed skinks without any stings.

Now, back to the question of whether or not these blue-tailed skinks are poisonous. From everything that I have read, there is no scientific evidence that skinks are inherently toxic when eaten by other animals. It is theorized that they could potentially harbor Salmonella bacteria but I have never heard of a documented case of this either. Many people hold the belief that when a skink in eaten by a dog or cat, it causes the animal to hold its head cocked and wander off to one side when walking. Veterinarians refer to these symptoms as vestibular syndrome and often cannot diagnose a cause. Vestibular syndrome is related to the inner ear or the parts of the brain that control balance and a sense of orientation to gravity. Our family witnessed this once with a beagle that we had and it lasted for several weeks but gradually improved to the point of normalcy. We did not witness her eating a skink, although she could have. However, there are many other more likely causes for this behavior including, inner ear infections, cysts or tumors, head trauma, parasites, etc. I suspect that inner ear issues are a common cause.

The largest species of skink in the Southeastern U. S. is the broadhead (or broad-headed) skink, reaching lengths of nearly thirteen inches. When mature, these skinks lose the blue tail and most of their striping to become a tannish brown. Males are larger than females and have a reddish color on the head, which intensifies during the breeding season. If you want to identify this species as a juvenile, you will need to look at the scales on the underside of the tail to separate it from the two species of five-lined skinks that inhabit our area. The central row of scales will be significantly wider than the other rows on either side. Broadheads have powerful jaws and will bite if harassed. If you want to see two males engaged in epic combat, give a watch to this YouTube link: https://www.youtube.com/watch?v=Z8qbexnZWew . Their stamina is truly amazing and they definitely come out with some battle scars.

It’s Been a Terrific Terrapin Season So Far

It’s Been a Terrific Terrapin Season So Far

As the Sea Grant Extension Agent in Escambia County, one of my program areas is to help restore a healthy estuary.  To do this we focus on educating the public how to improve water quality, restore habitat, and manage invasive species, but we also focus on how to monitor fish and wildlife.  The fish and wildlife I focus on are those that were once common in the bay and are trying to make a comeback – such as scallops and horseshoe crabs.  But there is another estuarine creature we are interested in that does not fall into the classic “bring them back” model and that is the estuarine turtle known as the diamondback terrapin.

The diamondback terrapin.
Photo: Molly O’Connor

Unlike scallops and horseshoe crabs, this is not an animal that people remember as a kid.  In fact, very few Floridians in the panhandle have ever heard of it.  Some older distribution maps of their range show that they exist from Cape Cod MA to Brownsville TX, but with a gap in the Florida panhandle.  That was because there was no scientific literature of the animal’s existence here.  And that was when the Panhandle Terrapin Project began – to confirm whether or not terrapins existed here.

 

In 2005, working with students at Washington High School in Pensacola, we began our search by placing “Wanted Posters” at boat ramps in Escambia and Santa Rosa counties near good terrapin habitat, which is salt marsh.  We began to get calls almost right away, but for a variety of other turtle species.  Folks were calling us with photos of box turtles, yellow-bellied sliders, and cooters.  It showed there was interest in the project but was evident they were not familiar with the terrapin.

Around 80% of the terrapin nests are depredated by raccoons, or some other predator.
Photo: Bob Blais

Volunteers log the number of female tracks they see on their beaches.
Photo: Cindy Marvel

I interviewed several ole gill netters to see if they remember ever capturing them – same response, “I never heard of those”.  I did show one gill netter a photo and he responded – “you know, I think we did catch a couple of these”.  But no confirmation of their existence here.  It was time to begin searching ourselves.

 

The team began to survey good terrapin habitat and walking potential nesting beaches looking for any evidence.  We did not find it.  Then one day in 2007 a gentleman working on a construction site responded to one of our “Wanted Posters”.  He said he had seen one of our terrapins.  After all of the calls that led to other species, I was not so sure – but he convinced me it might be.  So, we checked it out.  The sign was placed in good habitat and there were potential nesting beaches nearby.  We searched… and we found.  What we found were nests that had been depredated by raccoons.  There were empty eggshells laying around and two dead hatchlings.  There were also tracks in the sand.  Confirmation… there were terrapins here!

 

It was now time to take the show on the road and see if terrapins exist in other counties along the panhandle.  My wife and I would take part of our summer vacations and camp along the coast searching.  We found at least one record of a terrapin in each of the counties between the Alabama state line and Apalachicola River.  All of this was presented to the Florida Diamondback Terrapin Working Group of which there are members from the Florida Fish and Wildlife Conservation Commission.  Word was out.

Terrapins prefer sandy beaches and lay their eggs during daylight hours.
Photo: Molly O’Connor

A terrapin hatchling.
Photo: Molly O’Connor

 

 

 

 

 

 

 

 

 

 

 

The next step was to assess their status.  How many are here and how are those populations doing?

 

We did this by following a method developed by Tom Mann with the Mississippi Department of Wildlife.  Tom was monitoring terrapins in that state and the subspecies he worked with, the Mississippi Terrapin (Malaclemys terrapin pileata) was the one that was thought to be in Pensacola Bay.  So, it was Tom’s method we decided to follow.  This includes walking nesting beaches and logging individual tracks and depredated nests in 16-day cycles.  Tom’s model assumed that all mature females in the population nest each season and that they do not lay more than one clutch in a 16-day period.  The idea is that each track and nest represented one female, and assuming the sex ratio of male to female is 1:1, doubling the number of tracks and depredated nests found in that period would give an idea of how many adult males and females are in this group.  Seemed easy enough so these surveys became part of our project.

 

Another method learned by attending conferences was a 30-minute head count.  If you can find the lagoons where the terrapins actually live you can sit and count the number of heads you see in a 30-minute period.  It is true that 23 heads does not mean there are 23 terrapins, but the relative abundance can be monitored.  If you typically see 20-23 heads and over time that decreases to 11-15, then the relative abundance is declining.  It is a method that citizen science volunteers can do and so was included in the project.

Modified crab traps is one method used to capture adults.
Photo: Molly O’Connor

A diamondback terrapin being measured and marked before release.
Photo: Rick O’Connor

 

 

 

 

 

 

 

 

 

 

We also wanted to try and capture individuals to mark and tag.  Mark recapture is a method used to estimate populations but capturing terrapins has been historically difficult to do.  Several methods have been used by members of the Working Group and we have tried them as well.  We have captured terrapins, but very few.

 

In 2018 the Team partnered with the U.S. Geological Survey to increase the robustness of the project.  The Florida Fish and Wildlife Conservation Commission became interested in tissue samples from captured animal to study the genetics of the terrapins in this area.  Since 2015 we have trained 228 individuals to conduct surveys, and some have been with me that entire time.  Many of them have spent countless hours helping assess the status of this animal in our bays.  Many days they see nothing.  Others a few tracks or depredated nests.  Some locations have good luck with head counts, but many of them finding nothing.

The Mississippi terrapin found in Pensacola Bay is darker in color than the Ornate terrapin found in other bays of the panhandle.
Photo: Rick O’Connor

This terrapin has the coloration of the Ornate terrapin but was found much further west than the literature suggest it lives.
Photo: Rick O’Connor

I keep track of “Frequency of Occurrence” (FOO) – the number of surveys where some sort of terrapin encounter happens.  This encounter can be as simple as a track in the sand, but they had SOME encounter.  It is my hope that over time encounters with them will increase, just as I hope it does with scallops and horseshoe crabs.  Since 2007 the FOO has ranged from 12-86% of the surveys conducted, with an average of about 25%.  The best year was 2011 (86%), just after the Deepwater Horizon spill.  There was a steady increase in FOO from 2007 to 2012 when it took a significant drop.  However, this is not because the relative abundance of terrapins suddenly dropped.  2012 was the year I moved from the marine science program at Washington High School to Florida Sea Grant Extension.  There were all new volunteers and the learning curve started over.  They were not as good at detecting them as the previous group.  But that is changing.  2022 is looking to be a busy year for the team.

 

So far this year we have seen terrapin activity on almost every nesting beach between here and Apalachicola.  One site had 49 heads in a 30-minute head count!  There have been several active nests, numerous tracks, and plenty of depredated nests.  In addition, we have found one dead hatchling and captured two adults. Tissue from these have been collected for the genetic study.  But the strangest story this year… a security guard has told us of terrapin hatchlings that have been dropped on their guard shack by birds.  Sea birds are known to do this to try and crack open shells of mollusk so they can feed on them.  I have never heard of this with terrapins, not here or anywhere.

A dedicated volunteer is rewarded with a capture.
Photo: Rick O’Connor

It seems it is going to be a terrific year for the terrapin project this year.  It is exciting for our volunteers to have so many encounters and nice to know that the public is becoming more familiar with this animal.  I cannot say whether the population is increasing or not but our knowledge, understanding, and encounters are.

Wildlife on the Beach in May

Wildlife on the Beach in May

It is mid-spring and time of nesting for much of the wildlife in the area.  It is also noticeably warmer than our previous hikes.  Due to my work schedule, and the surveys for other nesting activity, I did this hike earlier in the month and later in the day, than I typically would have.  I began my hike at 1:00pm – near the hottest part of the day, and not the best time to see wildlife, but I definitely wanted to get a hike in this month and so this is when I could.

The Gulf was relatively calm on this early afternoon in spring.

It was warm.  On this day it was 83°F and there was a light breeze from the southeast.  On the previous hikes I needed my fleece.  Though I had it in my backpack, I did not need it today.  My hike was at Big Sabine and as usual, I began on the Gulf of Mexico.  The first thing I noticed when I crossed over the boardwalk was the number of people.  I usually hike in the early morning or late afternoon and see few humans.  But at mid-day the beach was full of people, and I probably looked strange walking among them with my long pants, long sleeved shirt, and boots.  The second thing I noticed was mats of Sargassum on the beach.

 

Sargassum is a floating brown algae we see in the warmer months in our part of the Gulf.  It is first an algae, not a true plant.  Algae lack roots, stems, and leaves.  They produce no cones, fruit nor flowers with seeds.  They are nonvascular, meaning they lack a system of vein-like tubes that move water around the plant.  Plants usually do have these tubes.  They are not called arteries and veins as they are in animals, but rather xylem and phloem.  Because algae lack this circulation system, they live emersed in the water.  Since they lack true roots they anchor to hard substrate, like rocks and coral, using a suction type apparatus called a holdfast.  The flexible, herbaceous stipe, analogous to the stem, flows in the current extending their blades (analogous to leaves) into the light.  Like plants, algae require water, carbon dioxide, and sunlight to photosynthesize their food.  Because of this they need to live in relatively shallow water, and they need a rocky bottom to attach their holdfast to.  We have little hard bottom and therefore less of the classic algae you read about in other parts of the world.

Notice the small air bladders on this Sargassum weed. These are used by the algae to remain near the sunlit waters of the open Gulf.

 

Sargassum has a different plan to deal with this problem.  They float.  When you look at this seaweed on the beach you will notice they have numerous small circular air bladders called pneumatophores.  These air bladders allow Sargassum to float in the sunlit waters of the Gulf and not worry about how, or where, they would attach their holdfast.

 

Large mats of Sargassum can be found floating out in the open Gulf and these mats provide a fantastic habitat for many small and large marine creatures.  There are sargassum crabs, sargassum shrimp, and even a sargassum sea horse.  There is a small filefish and a frogfish known as the sargassum fish.  It is the target for baby sea turtles that successfully made it from the beach, through the surf, and into the open Gulf without being consumed.  Here they will live and feed for many months at which time they are large enough to venture back out.  Larger fish often seek out these mats searching for food, and fishermen seek the mats knowing that larger fish are probably in the area.

 

These mats of Sargassum get caught in the large ocean currents and find their way to the middle of the Atlantic.  Here the ocean is calm, like the eye of a hurricane, and huge mats of Sargassum can be found piled up.  Christopher Columbus found this massive expanse of Sargassum while crossing the Atlantic.  Because it was calm here, and the Sargassum so thick, his ships became becalmed and he noted in his log to avoid this place, which was then called the “Sargasso Sea”.

 

On today’s hike there was quite a bit of this seaweed washed ashore.  Most of the marine life living in the seaweed sense the waves and the impending beaching, and jettison for mats further offshore.  So, you usually do not find many creatures in the seaweed washed ashore, but sometimes you do.  You can take a small dip net out deeper and grab some still floating and you may have better luck.  Today, I explored what was washed ashore and did not find much.  I did find a lot of plastic, and those who study Sargassum ecology will tell there is a lot of plastic debris caught up in the Sargassum mats.  Today I noticed a lot of bottle caps.  Not many bottles, but lots of bottle caps.  As many others do, we encourage everyone to dispose of the garbage properly.  I read this week of a manatee found near Mobile Bay earlier this year who died of cold stress but had swallowed a plastic bag, which was caught in his throat.  Marine debris kills.  Please dispose of your trash properly.

This crab pot float was one of several debris items washed in with the sargassum.

 

Heading inland to the dune field I heard sirens.  The beach patrol was answering a call.  I am not sure where, nor what the issue was, but these again are sounds I do not usually hear when hiking early and late in the day.  There are currents in the Gulf that can suck you out to sea, and each year we have visitors drown not knowing where these currents are, or how to get out of them if they are caught in one.  Pay attention to the colored flags and be careful.  I never saw, nor heard, an ambulance follow the beach patrol.  So, I am guessing everyone was okay on this call.

 

The dune field on this May afternoon was warm.  There was a light breeze from the southeast that kept things from getting too warm, but it was warm none the less.  As we move closer the hot days of summer the wildlife will move more at dawn and dusk, as well as in the evening.  I was not expecting to see a lot on this hike.

 

This flat area of the dune field was quite warm on this afternoon and made me think of crossing a desert.

This was an unusual site, a pigeon walking in the open dune field.

 

 

As always you can see what has been moving by searching for tracks and tracks, I did find.  Many of them were human, indicating the tourist season is upon us, but there were tracks of animals as well.  There were plenty from our friends the raccoon and armadillo.  I did notice more raccoon tracks this month.  I and my volunteers who survey nesting beaches notice more raccoon tracks this time of year looking for eggs.  I also noticed more snake tracks on this hike, they too are mating and moving much more.  The lizard tracks were fresh, and I have noticed these moving during the warmer parts of the day and their tracks running across the dune face told me they were very busy that day.

This straight line the sign of a tail drag by a lizard, most likely the six-lined skink.

Many who visit the dunes of our barriers find these burrow looking trails. These are made by beetles.

I followed this snake track until I found this – what appears to be a “tussle” the snake had with a possible prey.

 

Being spring you would expect flowers, and there were some, just not as many as you might expect.  Most of them were white and were blooming on plants near the boggy areas of the swales.  The conradina that blooms more in the winter, was done and the blossoms were gone.  I did see the early stages of the magnolia flowers trying to come up, but the bright green shoots of new growth on the pines were not visible.  There were bees, lots of bees.

The lavender blossoms of the false rosemary, which appeared in winter, are now gone.

White flowers were common on this spring afternoon. Such as this one on the spiny bull nettle.

Another white flower is seen on this Sagittaria growing in one of the swales between dunes.

 

I hiked through a small pine scrub area thinking I might someone in the shade avoiding the heat of the day but did not find anything.  I went along the edge of the tertiary dunes where they meet the maritime forest looking for the same thing.  Nothing, but there were tracks.  The cactus seemed to be more abundant this month.

 

The pine scrub offered one of the few places with shade.

The dune field of a Florida panhandle barrier island.

From atop of one of the higher dunes you can see the steep drop towards the marsh.

 

 

Along the ridge between the maritime forest and the salt marsh is where I found the otter slide last month.  I did not see any evidence of otters today.  The bird action was slower today as well.  Maybe because of the heat they too had settled somewhere.  I did not see an osprey, which is unusual.

Big Sabine as seen from atop one of the larger dunes.

 

As I reached the beach of the Sound, I did notice a LOT of digging by armadillos.  They had been very active.  There were no snakes or marsh rats.  There were again people, these were on jet skis.  There were a few fishing from small boats.  With no rain over the last week or so the visibility in the Sound was amazing, but I only saw one small blue crab.  No hermit crabs and not any fish.  However, the lagoon of the marsh the killifish, also known as bull minnows, were abundant and the males all aglow with their iridescent blue colors of breeding season.  The males were chasing each other all over the tidal pools and open water of the lagoon designating their territories for current breeding that would follow.  I did notice more crows than I usually do and what made me catch their attention was the constant calling at me and the hovering over me suggesting they too were breeding, and an active nest was nearby.

A blue heron is seen sitting in a pine overlooking Santa Rosa Sound.

A small Seserma crab is seen hiding under grass along the beach of the Sound.

The crows were numerous and active on this spring afternoon.

 

I was not expecting much hiking in the middle of the afternoon, but it is always good to do these just to see what is moving.  I hope to do another hike this month either early in the morning or late in the afternoon.  Maybe we will see more.

It may be hard to see, but there was a small duck enjoying the Sound.

With little rain over the last few days the water clarity was excellent and you could see the seagrass very well.

The Recent Fish Kill Near Pensacola Was Due to Stratification… Say What?

The Recent Fish Kill Near Pensacola Was Due to Stratification… Say What?

This began with a call from one of my volunteers who was checking salinity at Shoreline Park.  She reported the salinity, but also reported to smell of dead fish – though she could not see them.  I visited Shoreline Park the following day on another project and could smell it as well.  There was a large amount of dead seagrass washed ashore from a recent storm and I thought this may be the cause of the smell because I did not see the dead fish either.

 

When I got home, I checked the FWC fish kill database.  It reported a redfish kill in Pensacola Bay.  It is unusual to see a kill of only one species.  Many times, these are releases from fishing activity, particularly bait, and thought this must be the case – FWC did not mention the cause.  I let the volunteer know and asked to keep an eye out.

 

I reported this to the Escambia County Division of Marine Resources to (a) let them know, and (b) to find out if they had any idea of cause.  They replied that the location was incorrect.  The kill was actually near Galvez Landing on Innerarity Point.  He (Robert Turpin) had visited the site and did find any dead fish.  I have a lot of volunteers over that way so asked each to take a look.  They did not see any dead fish.  I asked them to keep an eye out and collect a dead fish if they saw one for testing.  Often when a large fish kill occurs, and it is only one species, the suspect cause is disease.  Tissue samples could confirm this.

 

And then came another call.

This time it was from one of our Master Naturalist who lives on the eastern shore of Mobile Bay.  He wanted to know what was up with all of the dead redfish along the shore of the bay.  He sent photos and his beach was littered with them.  I reached out to Mississippi/Alabama Sea Grant to see if they knew what was going on.  They had heard about the situation and knew the Alabama Department of Natural Resources was collecting samples.  The Gulf Islands National Seashore then reported large numbers of dead redfish along the National Shores property in Mississippi, something was up.

Dead redfish on the eastern shore of Mobile Bay.
Photo: Jimbo Meador

I eventually got word from Dr. Marcus Drymon at the Dauphin Island Sea Lab.  They had a team working on this.  Their team reported that stratification of the Gulf had created a hypoxic (low dissolved oxygen) layer on the bottom and the male “bull redfish” had gathered for breeding and died.

 

So, we are back to our title – what is stratification and how did this cause the fish kill?

 

Stratification is the layering of the water.  Less dense water will sit atop the more dense.  Water temperature or salinity can cause this density difference and layering.  Colder and/or saltier water is denser and will form the bottom layer.  If you have high winds, it will mix the water and the stratification disappears.  Tides and currents can affect this as well.

 

What they believe happened recently was excessive amounts of rainfall created a large layer of freshwater to move from Mobile Bay into the open Gulf.  The combination of tides and wind allowed a stratified layer to form.  The oxygen that marine life uses is dissolved into the water at the surface and referred to as dissolved oxygen (DO).  If the system is stratified, then the oxygen dissolved at the surface will not reach the bottom and hypoxia (low DO) can happen.  They this is what happen.  It just so happens that the large male redfish (bull reds) had congregated just offshore for breeding.  They are more sensitive to low DO than the smaller females and any juveniles.  So, the males died.  To answer the question as to why other fish did not die (what you typically see in a DO related fish kill) – the numbers were not mentioned by there was one reference to 4.0 ppm.  This is the high threshold of hypoxia.  Many fish can tolerate at this concentration, but the male redfish could not.

 

So, that is what we think happened.  The perfect storm of the demise of a group of male redfish just off of Mobile, and the carcasses drifted to other locations.