For those who lived in the Pensacola Bay area 50 or so years ago, this question comes up from time to time. By scallop I am speaking of the bay scallop (Argopecten irradians), the one sought by so many scallopers then and now. This relatively small bivalve sits on beds of turtle grass, gazing with their ice blue eyes, filtering the water for plankton and avoiding numerous predators. They only live for a year, maybe two. They aggregate in relatively large groups and mass spawn. Releasing male gametes first, then female, fertilizing externally in the water column, to create the next generation.
Bay Scallop Argopecten iradians http://myfwc.com/fishing/saltwater/recreational/bay-scallops/
These are unique bivalves in that they can swim… sort of. When conditions are not good, or a predator is detected, they can use their single adductor muscle to open and close the shells creating a current of expelling water that “pushes” them along and off the bottom. They were once found from Pensacola to Miami… but no longer. Scallops have become almost nondetectable in much of their historic range. Today they congregate in the Big Bend area of the state, and there they are heavily harvested.
What happened?
Well, if you look at the variety of causes for species decline around the globe habitat loss is usually at the top of the list. The habitat of the bay scallop are seagrass beds. There are many publications reporting the loss of seagrasses across the Gulf and Atlantic coast. Locally we know that the historic beds of the Pensacola Bay system have declined. We also know that some of those beds have shown some recovery in the last 20 years. But was the loss enough to cause the decline of the scallop?
Studies show that there is a strong association between seagrasses and scallops. The planktonic larva typically attached to grass blades a week or two after fertilization. This seems essential to reduce predation. Once they drop from the blades, vegetative cover is important for their survival. This suggests yes – any loss of seagrass could begin the loss of bay scallops.
What about water quality?
We do know that scallops need more saline brackish water – at (or above) 20 parts per thousand (20‰); 10‰ or less is lethal. Sea Grant is currently working with citizen scientists in Escambia County to monitor the salinity of area waters weekly. Though we do not believe the data is usable until we have 100 readings from each location, early numbers suggest that locations in Big Lagoon and Santa Rosa Sound are at 20‰ threshold. We do not know whether run-off engineering of the 1970s may have lowered the salinity to cause a die-off, and one would think (since they can swim) they would move to a better location. However, if salinities were low across much of their local range, and seagrasses were not available in areas where salinities were good, this could have a devasting impact on their numbers.
Then there is sedimentation. Studies show that young scallops (<20mm) that do not have seagrass to attach to settle on silty bottoms and their survival is very low. And then there are toxic metals, and other contaminants that scallops may have little tolerance for. It is known that juvenile scallops have a low tolerance for mercury.
Disease?
One study from the Tampa Bay area indicated that there was little loss of scallops due to disease and parasites.
And then there is overharvesting…
Scallops are mass spawners and there needs to be high numbers of adults near each other for reproduction to be successful. If people are taking too many, this can lead to more spaced adults and less chance of successful fertilization. This combined with environmental stressors probably did our populations in.
According to a publication from Sarasota Bay Estuary Program in 2010, populations of less than five scallops / 600m2 is considered collapsed. Sea Grant has been conducting volunteer scallop searches in the Pensacola Bay area for the last five years. In that time, we have found only one live scallop… we have collapsed. During the 2021 Scallop Search, 17 volunteers surveyed 4000m2 and found no live scallops. However, reports of live scallops outside of our surveys indicate they are still there. We will see what the future holds.
References
Castagna, Michael, Culture of the Bay Scallop, Argopecten irradians, in Virginia (1975). Marine Fisheries
Leverone, J.R. 1993. Environmental Requirements Assessment of the Bay Scallop
Argopecten Irradians Concentricus. Final Report. Tampa Bay Estuary Program. Pp.82.
Leverone, J.R., S.P. Geiger, S.P. Stephenson, and W.S. Arnold. 2010. Increase in Bay Scallop (Argopecten irradians) Populations Following Releases of Competent Larvae in Two West Florida Estuaries. Journal of Shellfish Research. Vol. 9, No. 2, pp. 395-406.
This is a famous fish. If you look back at the old tourism magazines of the early 20th century you will see a lot about tarpon fishing in Florida. As a matter of fact, some say that tarpon fishing was the beginning of the tourism industry in the state. Also known as “silver kings”, they put up a tremendous fight which anglers love, particularly on lighter tackle. It is a sport fish, not sought for food, so catch and release has been the rule for years. But those who seek them will tell you it is worth the fight even if you must release it.
Tarpon have been a popular fishing target for decades. Photo: NOAA
Tarpon (Megalops atlantica) are large bodied, large scaled fish, with a deep blue back and silver sides. They are a large fish, reaching over 8 feet in length and up to 350 pounds. They tend to travel in schools and are often associated with other fish, such as snook2.
It has always been thought of as a “south Florida fish”. As mentioned, down there it is a popular fishing target for tourist and residents alike. Many charter captains specialize in catching the fish and they have been featured in fishing programs. But you do not hear about such things in the Florida panhandle. Hoese and Moore1, as well as the Florida Museum of Natural History2 both indicate that they are in fact in the Florida panhandle. As a matter of fact, this fish has few barriers and has the distribution of the classic “Carolina fish” group. That includes the entire eastern seaboard of the United States, the entire Gulf of Mexico, and the Caribbean1. The Florida Museum of Natural History indicates they are found on the opposite shores of the Atlantic Ocean and may have made their way through the Panama Canal to the Pacific shores of the canal. Within this range they are known to enter freshwater rivers. They seem to have few biogeographic barriers.
I grew up in the panhandle and remember hearing about them swimming in our area when I was younger. Fishermen said they would throw all sorts of bait at them. Artificial lures, live bait, cut bait, you name it – they tossed it… the tarpon never would take it. Catching one here was almost impossible. The flats fishing charter trips for tarpon in south Florida would not happen here. I remember once diving in Pensacola Bay near Ft. Pickens. We were looking for an old Volkswagen beetle that had been sunk years ago when at one point the water became very dark – almost like storm clouds had rolled in. When my buddy and I both looked up we saw a school of very large fish swimming above us. We were not sure what they were at first but as we slowly ascended, we realized they were tarpon. It was pretty amazing.
An interesting side note here. In 2020 tarpon were once again seen swimming around the Pensacola area but this time they WERE taking bait. There were several reports of tarpon caught off the Pensacola Fishing Pier and inside the bay. Why change over all this time? I am not sure.
The ladyfish (or skipjack) is the smaller cousin of the tarpon, but puts up a good fight as well. Photo: University of Southern Mississippi
Tarpon belong to the family Elopidae which also includes another local fish known as the “ladyfish” or “skipjack” (Elops saurus). This is a much smaller fish reaching about 3 feet (and that would be a large ladyfish). The scales of this family member are much smaller, but the fight on hook and line is just as large. The characteristic that places these two fish into the same family (and these are the only two in this family) is the hard bony gular plate found between the right and left side of the lower jaw (in the “throat” area).
Like tarpon, it is not prized as a food fish but more of a game fish. It has the classic wide distribution of the “Carolina fish group” – the eastern seaboard of the United States, the Gulf of Mexico, down to Brazil. Like the tarpon, it is found in brackish conditions but is not mentioned in freshwater. Again, few biogeographic barriers for this fish.
Both members of this family provide anglers young and old with a lot of enjoyment.
1 Hoese, H.D., R.H. Moore. 1977. Fishes of the Gulf of Mexico; Texas, Louisiana, and Adjacent Waters. Texas A&M Press, College Station TX. Pp. 327.
Sargassum washed ashore after a storm on Pensacola Beach. Photo credit: Carrie Stevenson, UF IFAS Extension
I am sure it drives the tourists a little crazy. After daydreaming all year of a week relaxing at the beach, they arrive and find the shores covered in leggy brown seaweed for long stretches. It floats in the shallow water, tickling legs and causing a mild panic—was that a fish? A jellyfish? A shark? Then, of course, high tide washes the seaweed up and strands it at the wrack line, shattering the vision of dreamy white sand beaches.
But for those visitors—and locals—willing to take a closer look, the brown algae known as sargassum is one of the most fascinating organisms in the sea. The next time you are at the beach, pick some up and turn it over in your hands. Sargassum is characterized by its bushy, highly branched stems with numerous leafy blades and berry-like, gas-filled structures. The tiny air sacs serve as flotation devices to keep the algae from sinking. This unique adaptation allows it to fulfill a niche at the top of the water column, instead of growing at the bottom or on another organism.
The sargassum fish blends incredibly well into its home within sargassum mats. It uses handlike pectoral fins to move around. Photo credit: Reef Builders
Sargassum tends to accumulate into large mats that drift through the water in response to wind and currents. These drifting mats create a pelagic habitat that attracts up to 70 species of marine animals. Several of these organisms are adapted specifically to life within the sargassum, reaching full growth at miniature sizes and camouflaged in shape, pattern, and color to blend in. These very specialized fauna include the sargassum crab, the sargassum shrimp, sargassum flatworm, sargassum nudibranch, sargassum anemone, and the sargassum fish! The sargassum fish (Histrio histrio) is in the toadfish family, a group of slow-moving reef fish that pick their way through coral and algae by using their pectoral fins like hands. Sea turtle hatchlings will spend their early years feeding and resting within the relative safety of large mid-ocean sargassum mats.
The small air-filled sacs of sargassum allow it to float on the surface, becoming the basis of a teeming ecosystem. Photo credit: Carrie Stevenson, UF IFAS Extension
Over time the air sacs lose buoyancy and the sargassum sinks, providing an important source of food for bottom-dwelling creatures. If washed ashore, many of the animals abandon the sargassum or risk drying out and dying.
In general, most of the larger, familiar seaweeds like sargassum are brown algae. Brown algae (including kelp and rockweed) have colors ranging from brown to brownish yellow-green. These darker colors result from the brown pigment fucoxanthin, which masks the green color of chlorophyll. Extractions from brown algae are commonly used in lotions and even heartburn medication!
By Tory Moore, UF/IFAS Communications & Ray Bodrey, UF/IFAS Extension Gulf County
As boaters across the state take to Florida’s coast to scallop, UF/IFAS Extension and Florida Sea Grant agents ask enthusiasts to keep these tips in mind for a safe, fun and sustainable trip.
Scallops are sensitive to environmental changes and, due to their relatively short lifespan, local bay scallop populations are susceptible to periodic collapses. To enjoy recreational scalloping for years to come, it is important that safety and conservation stay top of mind.
Safety
Remember, you are not alone out on the water. Other boaters and scallopers, manatees, sea grasses and other wildlife surround you.
In 2020, the leading cause of boating accidents was motorists failing to pay attention to surroundings according to the Florida Fish and Wildlife Conservation Commission boating accident report. Florida leads the nation in the number of registered vessels, and it is important for boaters to be aware of others around them to prevent accident, injury or death.
While in the water, be sure to display a dive flag to grab the attention of boaters passing by.
“We often see folks not using diver down flags,” said Ray Bodrey, UF/IFAS Extension and Florida Sea Grant agent said. “Be safe on the water and be sure to place your diver down flag in your scalloping area so boaters know you are there.”
Conservation
When boating in shallow areas, watch out for seagrass beds. Wildlife, including scallops, depend on seagrass and protecting the grasses from boat anchors and propellers helps to keep populations healthy. Just a couple of minutes of negligence by a boater can cause a decade of impacts to sea grass. Propellor and anchor scars are preventable by following these simple best practices.
“Seagrass scarring is a big issue in Florida,” Bodrey said. “It takes a long time for seagrass to recover from such an injury. Remember, seagrass is a scallop’s best friend. Seagrass provides a health habitat for scallops by providing oxygen and a camouflage from predators.”
To support future scallop populations, return scallops smaller than 1 1/2 inches. Smaller scallops likely have not spawned yet and since their life span is roughly one year, it’s important that each scallop has the opportunity to contribute to the scallop population.
Consider only collecting what you plan to eat. While many people strive to “limit out,” be realistic about how much you will eat and how much you may or may not want to shuck.
Scalloping regulations
Remember, scallop seasons differ by county. Limits are season – and location – specific. Harvesting scallops requires a current Florida recreational saltwater fishing license unless you are on a chartered trip.
It’s important to be aware of the regulations for the area you are scalloping and follow them. Not only are these regulations law, but they are also important for keeping scallop populations healthy for your future enjoyment.
“Many bays in Florida are struggling to maintain a healthy scallop population,” said Bodrey. “Follow all FWC rules and regulations so that we have a recreational scallop harvest season for years to come.”
Cleaning and cooking scallops
On the boat
Upon collection, place scallops on a wet towel on top of ice in a cooler. This prevents spoilage and water from entering their shells. Drain your cooler frequently to keep bacteria growth at a minimum.
Back on land
You will want to shuck your scallops the same day they are caught. If you shuck your scallops on shore, be sure to dispose of the shells or soft tissues properly. Do not dispose of them in high-traffic water areas near shore or in swimming areas.
Before shucking, make sure to wash your hands and shucking utensils.
Remove any traces of the surrounding tissue as possible, you want to only eat the circular white muscle meat. Scallop meat should be stored in the refrigerator and cooked or frozen within 24 hours of catching and shucking. Frozen scallop meat is best enjoyed up to three months.
This is one strange, primitive, dinosaur-looking fish. They have large scutes embedded in their skin that give them an armored look. They are big – reaching 14 feet in length and 800 pounds (though the Gulf sturgeon does not reach the large size of their cousin the Atlantic sturgeon). They resemble sharks with their heterocercal caudal fin and possess long whiskers (barbels) suggesting a benthic mode of feeding.
Sturgeon are large fish. The barbels (whiskers) are for finding prey buried in the sediment. Notice the raised ganoid scales of this ancient creature. Photo: U.S. Fish and Wildlife Service.
Panhandle residents know them from their impressive leaps as they head upriver for spawning in the spring. The loud splash from one of these leaps can be heard for a long distance and is a concern for boaters who may be zipping up and down one of the local rivers on a jet sky, or even a bass boat. When in college, we asked one of the professors – “why do mullet jump?”. He paused for a second and responded – “for the same reason manta rays jump”. There was another longer pause. Understanding what was going on we took the bait and asked – “okay… why do manta rays jump?” – “we don’t know”. However, that was in 1980 and a lot has been learned since. We know that not only do mullet and mantas leap, but baleen whales and sturgeon do as well. It is believed that baleen whales leap to communicate during the breeding season. Since sturgeon breed in panhandle rivers, it is believed that this is the reason they may do so. Scientists have also found it helps adjust their swim bladders with internal gas making them more buoyant in the water.
Like salmon, sturgeon swim up rivers to breed and spawn in the spring. Fertilization is external and the gray-black eggs are laid on the substrate at the bottom. The newborn and adults spend the remaining spring in the rivers, and the adults do not feed at this time. In summer all head for the estuaries where the adults begin feeding with a vengeance. They feed on a variety of benthic invertebrates and prefer sections of the bay that are well oxygenated. Sturgeon spend the summer and much of the fall in the bays until the temperatures begins to drop at which time they head into the open Gulf of Mexico. The spring, they find their breeding rivers and the reproductive cycle begins again. This is a long-lived fish, reaching up to 50 years in age.
As far as the biogeography of this species, it is an interesting one. They have been around for about 200 million years. This was about the time the whole “Pangea” movement was going on – Florida did not look like Florida then. There was an opening between what is now the southeastern United States and the Florida peninsula. The water moving through this was called the Georgia Seaway or the Suwannee Channel. This allowed marine species to easily move from the Atlantic to the Gulf of Mexico. It was believed the current in this seaway was significant enough to keep silt and clays from reaching what would be become peninsula Florida, which was probably a submerged region of islands at the time.
During those times the Atlantic sturgeon (Acipenser oxyrinchus) inhabited this region, using southeast rivers for breeding. About 25 million years ago global land mass changes began a period of ice formation that encouraged sea level to drop and the peninsula portion of Florida was exposed – the Florida people know today. However, this new peninsula isolated populations of sturgeon (and other fish at that time) from reaching each other. As time moved on, different genetic changes occurred in both populations to produce offspring that varied from each other. These external morphological changes were enough to let you know they were different, but genetically they are close enough to still breed. In these situations, they have deemed “subspecies” of each other. The Atlanticsturgeon (Acipenser oxyrinchus oxyrinchus) and the Gulfsturgeon (Acipenser oxyrinchus desotoi). It is the Gulf sturgeon we find along the panhandle. This process of producing new subspecies and species due to population isolation over time is called speciation.
Another interesting trend is the original range of the Gulf sturgeon was from the Texas/Louisiana border to about Tampa Bay. This suggest that the fish took advantage of numerous rivers for breeding but there was a barrier as you reach the tropics. Whether that barrier was climatic (temperature) biological (food source) or something else I am not sure. With the high concentration of sturgeon in the panhandle you might think they require the alluvial rivers of this region. But sturgeon are as common in tannic rivers, such as the Suwannee and Yellow Rivers, as they are in those alluvial ones, such as the Escambia and Apalachicola.
Today, their range is even smaller. They are now found only in the rivers between Louisiana/Mississippi border to the Suwannee River. This range reduction is probably due to habitat alteration (much of it human induced – such as dams) and overharvesting (the eggs of the sturgeon are used for caviar). Today all species and subspecies of sturgeon are protected by the endangered species act.
Because this is an ancient fish, the biogeographic story of the sturgeon is an interesting one and shows how speciation occurs over time with all life. They are really cool fish and, if you have not seen one leap yet, I hope you get to. It is pretty amazing.
In our continuing series on the biogeographic distribution of island vertebrates, this week we look at a creature that, for some, is as scary as sharks – the rays. The term stingray conjures up stinging barbs and painful encounters, and these have happened, but rays are easily scared away by our activity. Occasionally people will step on one and the venomous spine is used to make you move your foot. You can avoid this by shuffling your feet when moving across the sand. Rays detect the pressure and move before you reach them. Again, negative encounters with rays are not common.
The Atlantic Stingray is one of the common members of the ray group who does possess a venomous spine. Photo: Florida Museum of Natural History
There are 18 species of rays (from 9 families) found in our area. An interesting note, only eight of those possess a barb for stinging, and five are from the family Dasyatidae (the stingrays). Others that have barbs include the butterfly ray, cownose ray, and the eagle ray.
Rays are related to sharks but differ in that (a) the pectoral fin begins before the gills slits, and (b) the gill slits are on the underneath of the body – not on the side as found in sharks. Shark distribution seems to be controlled by water temperature. We see this with ray distribution as well, but interestingly the skates seem to be restricted to the Gulf of Mexico. Some are found almost exclusively in the east or west side of the Gulf.
Skates resemble stingrays but lack the venomous barb. They will usually have small thorns on their bodies and lay their developing embryos in a leathery egg case folks call “mermaid’s purse” when they wash ashore. There are four species found in the Gulf, but the spreadfin skate is ONLY found in the Gulf of Mexico and is not found along the Florida peninsula. The clearnose skate, which can be found all along Florida and the eastern seaboard of the U.S., is absent from western Gulf. It is interesting to try and understand why. What barrier keeps these two skates from colonizing the entire Gulf?
There is a large plume of muddy freshwater that expands from the Mississippi River into the Gulf off Louisiana. This plume could be a barrier for coastal species trying to expand their range. However, the spreadfin skate is reported to be an outer continental shelf species and may not be influenced by this lower salinity water. So, what is their story?
And why are these not found in the Caribbean? In the Caribbean you do enter tropical waters where coral reefs become more common. There is certainly a species shift when you reach this zone and it could be the food needed by these skates is not found here – a biological barrier. Many find these biogeographic situations interesting.
There are 12 species that have the typical “Carolina marine fish” distribution, which means they are found throughout the Gulf up the eastern seaboard to Massachusetts and south to Brazil. Two, the Atlantic torpedo ray and the roughtail stingray, expand their range farther into Canada. As a matter of fact, the roughtail stingray prefers colder waters.
Torpedo rays are an interesting group. This family of fish includes two species here in the Gulf, the Atlantic torpedo ray and the lesser electric ray. Yep… these two have special muscle cells that can deliver an electric shock. It is believed this electric current can detect and stun prey as well as repel predators. The voltage is not dangerous but will get your attention.
Three of those “Carolina marine species,” the guitarfish, the lesser electric ray, and the yellow stingray, do not reach Massachusetts. Their distribution ends at North Carolina. You would have to guess water temperature as a barrier here. The warm Gulf stream begins heading east across the Atlantic Ocean off Cape Hatteras towards Europe. They could follow this current to Bermuda, but they have not been reported there. This could be due to depth (pressure), being benthic fish, or food barriers.
There is one family that is tropical, the sawfish. These bizarre dinosaur looking creatures were once common in the estuaries of the Gulf region. They are now rare and protected.
One species of stingray, the Atlantic stingray has been found in the lower reaches of Louisiana rivers. Like bull sharks, salinity may not be a barrier for them.
And then we have our “world travelers”. The manta and eagle rays are found across the globe in tropical waters, and eagle rays are common in temperate parts of the world.
The distribution of our rays is not as universal as sharks. The skates in particular have an interesting distribution pattern. Pensacola lies right at the boundary of the eastern and western Gulf of Mexico, so we find both geographic groups here. Though they may scare many people, rays are fascinating creatures and cool to see.
