Many of us are given that Birds and the Bees talk; another majority have had to give it as an adult to their kids. It is usually an awkward talk, but someone had to step up to the plate and put on a straight face. I am happy to be the one today to discuss one section of the Birds and the Bees of the Sea, batch spawning. Batch spawning, also known as broadcast spawning, is the coordinated release of gametes (sperm and eggs) into the water column. Batch spawning is not just relegated to fish, many species of invertebrates also batch spawn. Some of the most commonly encountered batch spawners include Florida Pompano (Trachinotus carolinus), Eastern Oyster (Crassostrea virginica), Red Drum (Sciaenops ocellatus), Red Snapper (Lutjanus campechanus), and Gag Grouper (Mycteroperca microlepis), to name a few. In fact, most gamefish species in the Gulf of Mexico are batch spawners. This has its advantages, but also has its major disadvantages. We will dive headfirst into a few representative species of saltwater organisms that batch spawn, and their respective life stages to help shed some light on reproduction in the marine world.
Baby Snapper – Thomas Derbes II
Eastern Oysters are a perfect representative for invertebrate batch spawning. I have gone over their life cycle in a previous article (Click Here), but I will just quickly go over their spawning habits and life history. Eastern Oysters typically spawn during the changing of the seasons, particularly from Spring to Summer and Summer to Fall. As humans, we see these changing temperatures and weather fronts as an opportunity for a new wardrobe, but these changes are triggers for oysters to spawn. Once one oyster releases their gametes into the water all of the mature oysters in the area will start releasing their gametes. Waiting to sense for other gametes in the water is a very smart tactic. This allows for a coordinated spawn between masses of oysters and (hopefully) increases the fertilization rate of the eggs. Since oysters cannot move, batch spawning is the most beneficial way for them to reproduce. Females can release anywhere from 2 to 70 million eggs in one spawning event, with only a dozen or so becoming adults. Since they are batch spawners, the larvae are left unprotected by the parents and suspended in the water column for the first few weeks, leaving them susceptible to predation by filter feeders and bad water quality. Once the larvae have reached the pediveliger stage, they will settle out and “walk” along the bottom of the estuary until they find a suitable place to call home, usually another oyster or hard substrate. After 1-3 years, the oyster will mature and begin batch spawning when conditions are ripe, and the cycle continues!
The Oyster Life Cycle – Maryland Sea Grant
Fish in the Lutjanidae (snapper) family are the perfect representative for batch spawning with fish. Snappers of all species are known to congregate and have mass spawning events typically around a full moon. The mutton snapper (Lutjanus analis) of South Florida and the Florida Keys are very well known for their ability to form massive congregations of tens of thousands of fish along the reef starting in April. Once the spawning commences, the mutton snapper will form a small subgroup of up to 20 fish in the late afternoon. This subgroup will travel to depths of up to 100ft to perform their spawning event. During this event, the female will signal to the males that she is about to release her eggs. The males will then rub up against the side of the female snapper, helping her release eggs while simultaneously releasing their milt (sperm). When the milt is released, the sperm is activated by the seawater and begins to swim. Eventually, the eggs are fertilized and an embryo is formed.
Massive Two-spot red snapper aggregation ready to spawn in Palau – R.J. Hamilton
18 – 24 hours later, the embryo is now a larval fish consisting of a yolk sac and lacking a mouth, eyes, and most organs. The yolk sac consists of amino acids and other nutrients that provide energy to the developing larvae. These larval fish have until their yolk sac runs out to develop the lacking vital organs, which usually takes between 24 – 48 hours. Only a very small percent of juvenile snapper make it to adulthood due to predation during their larval stage and predation as a juvenile. In fact, sharks and other large predators will prey on the snapper as they congregate and spawn, and filter feeders like manta rays are known to pass through an active spawning congregation to consume all the fertilized eggs and larval fish.
Well, I hope I didn’t scar anyone too badly. Batch spawning is fairly common in the marine biology world, and you can sometimes experience a spawning event without even knowing it. As for positives, this allows for many eggs to be fertilized at a time multiple times a season and for the larval fish and shellfish to be distributed through the estuary and reef via tides and waves. A major negative is the vulnerability of the juvenile and larval fish and shellfish, but the sheer number of eggs produced and fertilized helps outweigh the high potential for predation and unexplained loss of fertilized eggs and juveniles.
One of several “flatfish” inhabiting our Panhandle coastal waters, the ocellated flounder (Ancylopsettaommata) is one of the more striking species, in my opinion. From the four distinctive eye spots (ocelli) to its incredible variability in background patterns, I must just say that it is a beautiful creature. Flounders are unique among fish, in that early during larval development one eye will migrate over to join the other and the fish will orient to lay on its side when at rest. Only the top side will have coloration and the bottom side will be white. While the eyes end up on the same side, the pectoral and pelvic fins remain in their traditional positions, although the bottom-side pectoral fin is reduced in size.
Not the Biggest but Definitely one of the Coolest Flounder Species Around
Ocellated flounders are always left-eyed, meaning if you stood them up vertically with their pelvic fins down, the left side of the body has the eyes. When laying on the ocean floor, their independently moving eyes can keep a lookout in all directions. However, flounders tend to remain immobile when approached, depending on an awesome ability to camouflage themselves from predators. They can flip sand or gravel onto their top side which hides their outline and their ability to match the color and texture of the surrounding substrate is phenomenal.
This species is a fairly small fish, reaching lengths of about ten inches. However, they are by no means the smallest flatfish around. We also have hogchokers (a member of the sole family, 6-8 in.) and blackcheek tonguefish (to 9 in.). These are dwarfed by the larger Gulf flounder and Southern flounder which are highly prized table fare by fishers along our coasts and can reach sizes that earn them the nickname of “doormat” flounders. Regardless of the species of flounder you observe, it is unquestionably one of the super cool animals we have the privilege of living with here along the North Florida Gulf Coast.
The University of Florida/IFAS Extension & Florida Sea Grant faculty are reintroducing their acclaimed “Panhandle Outdoors LIVE!” series on St. Joseph Bay. This ecosystem is home to some of the richest concentrations of flora and fauna on the Northern Gulf Coast. This area supports an amazing diversity of fish, aquatic invertebrates, turtles and other species of the marsh and pine flatwoods. Come learn about the important roles of ecosystem!
Registration fee is $40. You must pre-register to attend.
Even though oysters have a hard shell that even humans have a hard time opening, they do have natural predators in our waters that can easily slurp up a couple dozen. Your usual oyster slurping suspects include oyster drills, blue crabs, and fish (such as the black drum). In this article, we will focus on the 3 major predators that contribute the most toward natural mortality in oysters here in the Florida Panhandle.
The Oyster Drill
When it comes to the marine snail world, oyster drills would win an oyster-eating contest. Oyster drills (Urosalpinx cinerea) are marine gastropods that grow to sizes of 0.5 – 1 inch. Oyster drills can be found all along the Atlantic coast of North America and the Gulf of Mexico, and they have been accidentally introduced into Northern Europe and the West Coast of North America. These small but mighty snails have become specialized in consuming oysters. Using chemotaxis, they locate their prey oyster. Once they find it, they secrete an enzyme to soften a portion of the oyster shell. Once softened, they drill into the shell and siphon out oyster meat. Oyster drills have been known to occur in great numbers when the environmental conditions are prime and can wipe out not only entire oyster beds but also clam beds. Oyster drills do have natural predators as well, but these predators also consume oysters.
An Oyster Drill (Urosalpinx cinerea) – Barnegat Bay Shellfish
The Blue Crab
Most of us know about the very tasty blue crab (Callinectes sapidus), but many do not know that it is a major consumer of oysters, especially on an oyster farm. Blue crabs are a decapod crab (meaning 10 legs) of the swimming crab family Portunidae. Blue crabs can indeed swim and their last leg on each side has developed into what are called paddle fins. Juvenile oysters are the main target for blue crabs, but they have been observed eating adult oysters when given the opportunity. On an oyster farm, blue crabs can get into an oyster bag when they are very small. Once inside, they have an all-you-can-eat buffet of oysters, and can quickly wipe out a bag of oysters. Oyster farmers have to be very cautious and must either remove the blue crabs manually or dry their bags out in hopes of destroying any blue crabs. Blue crabs can easily break open a juvenile oyster, but for them to consume an adult oyster, they will wait for it to open to feed before shoving a claw inside of the shell to keep the oyster open. Once they have their claw in the shell, they will use their other claw to consume the oyster.
Blue Crabs (Callinectes sapidus) Pulled Out Of Oyster Bags – Thomas Derbes II
The Fish
Even though oyster-eating fish like black drum (Pogonias cromis) and sheepshead (Archosargus probatocephalus) are much bigger than snails and crabs, they tend to contribute less to oyster mortality on oyster farms. However, during certain seasons wild oysters and other shelled invertebrates can contribute up to 33% of a black drum’s diet (more here). Fish will usually congregate around oyster beds and farms, but they are more interested in consuming oyster predators like crabs and snails. The black drum is a fish that was built for oyster consumption. While black drum lack sharp teeth, they have crushing plates in their throat that can crush an oyster shell which allows the drum to eat the oyster meat. Many oyster farmers welcome these fish on their farms as a free source of anti-fouling and predator deterrent (in the form of consumption).
Black Drum (Pogonias cromis) Caught On A Whole Oyster – Thomas Derbes II
There are many more oyster predators, but these are the top 3 in terms of threat and ability to consume/do detriment to oyster beds and farms in the Florida Panhandle. While oyster drills rank up towards the top, crabs and fish can also greatly contribute to natural mortality.
References
Flimlin, G., & F Beal, B. (n.d.). Major Predators of Cultured Shellfish. https://shellfish.ifas.ufl.edu/wp-content/uploads/Major-Predators-of-Cultured-Shellfish.pdf
You might have seen a floating oyster farm while driving over Garcon Point Bridge or along Scenic Highway. Many people know them for the beautiful, tasty oysters they produce, but those farms have a major ecological benefit that many aren’t aware of. First, the oysters in those cages act as a very efficient water filter, filtering upwards of 30 gallons per day. The floating farms also act as an oasis for other marine creatures, from crustaceans to finfish, and can help increase the biodiversity in the area. Oysters are also great at sequestering carbon into their shells. Today, we will go over these ecological benefits and proper etiquette when maneuvering around the farms to enjoy some of the ecological benefits of the oyster farm.
Florida Pompano Caught Off an Oyster Farm – Thomas Derbes II
Besides being tasty, oysters are very well known for their ability to filter massive amounts of water in a single day. Research has shown rates of up to 50 gallons per day in a laboratory setting, but they filter upwards of 30 gallons per day in the wild. With most oyster farms in the area having more than 500,000 oysters on their farm, that’s more than 15,000,000 gallons of water per day per farm! Oysters can filter out any excess sediments from the water, forming them into small packets and depositing the sediment on the bottom of the bay, keeping the sediments from being re-suspended. This is very beneficial to any bay or estuary as eutrophication (More Here on Eutrophication) has been an issue in almost every bay in the southern United States.
Another benefit to oyster farms is that it is a floating oasis for all types of marine creatures. Blue crabs and stone crabs are a common threat to oysters, and they love to congregate around oyster farms waiting for an easy meal from a dropped oyster or oyster spat on cages. Common bay fish, like the Spotted Seatrout, Sheepshead, and Red Drum, have been known to hang out under the cages consuming smaller finfish and crabs, but some uncommon fish like Tripletail and Florida Pompano also patrol the cages looking for a meal. Because of its ability to hold all types of fish, fishermen love to fish around the oyster farms. Fishing around oyster farms is allowed, but most farmers want the boats to stay on the boundary of the farm and not inside of it. This is due to there being lines under the surface of the water that could potentially damage any lower unit and can cut free a line of cages. Also, it is against state law to be within the boundary of the farm if you are not an authorized harvester of that lease, and I have personally seen FWC enforce those rules. As a seasoned oyster farmer once told me “We know our farm holds fish and it is okay for them to fish the farm, heck put out some blue crab traps around it, but do not mess with the cages and stay outside of the boundary and we can all live in harmony.”
Tripletail Caught Off An Oyster Farm – Brandon Smith
Last but not least is the ability of oysters to sequester carbon and excess nitrogen into their shells and pseudofaeces (aka bio-deposits). Carbon and nitrogen sequestration is a crucial service provided by oysters that helps battle global climate change. Just as they do with excess sediments, they deposit excess carbon and nitrogen into bio-deposits that accumulate on the bottom, keeping them from being re-suspended into the waters. Oyster reefs are currently on the decline around the world, and their decline has “resulted in a forfeiture of several ecosystem services” including carbon and nitrogen sequestration and water filtration. (More Here on Carbon Sequestration)
While oysters might be tasty, we have learned about some of the ecological services oysters provide to an estuarine environment. From water filtration to increasing biodiversity to carbon/nitrogen sequestration, oysters are a major benefit to any estuary and can help fight climate change and eutrophication. Next time you see an oyster farm or reef, give oysters (and farmers) a little appreciation for their hard work in helping make the world a healthier place!
Pompano?! More like Pompa-YES! Growing up in the Panhandle of Florida, I was exposed to many great fishing seasons and opportunities, from the Cobia (Rachycentron canadum) run in the spring to the “Bull” Red Drum (Sciaenops occelatus) run of the fall, but my absolute favorite season was the Florida Pompano (Trachinotus carolinus) run on the beaches. While I enjoyed being on the boat scouring the beaches with a small bucktail jig, casting at sliver flashes in the cuts of the sandbar, I had my most memorable trips on the beach with a few rods, sand spikes, and a “flea rake.” There were no bad days on the beach (as they say, it’s better than a day in the office), and when you happen upon a honey hole, it makes for an incredible day with very little effort and usually an incredible dinner to follow. Since we are rapidly approaching peak pompano season, I will pay homage to the “Silver Surfers of the Emerald Coast” with a little overview of the life of a Florida Pompano.
Beach Fishing for Florida Pompano is for Everyone, Young and Old – Thomas Derbes II
Florida Pompano have a very wide range, from Massachusetts to Brazil, and are a member of the family Carangidae (aka the Jack Family). It is a very popular sport and commercial fishery, and its rapid growth rate makes it a prime candidate for aquaculture. Florida Pompano are highly migratory fish, and they can run from the Florida Keys all the way to Texas and back in a season. In the Florida Panhandle, the Florida Pompano run starts in April/May lasting until July, with a bonus fall run in October/November when they are returning south. When fishing off the sandy beaches of the Florida Panhandle, you can run into its cousins the Permit (Trachinotus falcatus) and Palometa (Trachinotus goodei) who often get mistaken for a Florida Pompano. Another thing they have in common with Florida Pompano is their love of crustaceans including the Mole Crab (aka Sand Fleas) (Emerita portoricensis) and Atlantic White Shrimp (Litopenaeus setiferus).
Just like most members of the family Carangidae, Florida Pompano are considered “batch spawners.” A batch spawner is when a female releases her eggs into the water column and a male simultaneously releases his sperm into the water column. Female Florida Pompano can release upwards of 800,000 eggs per spawning season, and Florida Pompano typically head offshore in early spring to October in the Gulf of Mexico to spawn, and their juveniles return to the beach to grow along the shoreline. Florida Pompano can reach an aquaculture harvest size of 12 inches within one year, and males reach maturity in 1 year whereas females mature after 2 to 3 years.
Florida Pompano Eggs 12 Hours Post Fertilization – Thomas Derbes II
When it comes to table fare, Florida Pompano ranks very high on my personal fish list, and many chefs love serving pompano at their restaurants due to the great, mild taste and fillets that are of even thickness. Their diet of crustaceans helps yield a buttery, almost crab flavor and the meat is very flaky and white. There are many preparation techniques for Florida Pompano, from grilled whole to pan-fried, and pompano have even inspired their own cooking technique, “Pompano en Papillote,” or baking pompano in parchment paper.
Beautiful Florida Pompano Caught Off Pensacola Beach, Florida – Thomas Derbes II
When fishing for Florida Pompano off the beach, most anglers employ a large rod (usually a 10ft rod) with a 20lb fluorocarbon double drop loop rig and pyramid weight. The larger rod allows for maximum casting distance from the beach, giving beach anglers a chance to reach behind the first sandbar. Most anglers will bring either fresh dead shrimp or a flea rake with them to catch the prized bait, mole crabs. Pro tip, when casting out the rods, make sure you have a bait close to the shore in the “trough” and not just past the sandbar. (Learn More About Rigging Here!) If you plan to harvest a Florida Pompano, make sure you check your local regulations. In the Florida Panhandle, Florida Pompano must be 11 inches (fork-length) or larger with a daily limit of 6 per angler.
My nephew showing off his prized Florida Pompano – Zach Saway
I hope you have enjoyed this profile for the Florida Pompano. Now is the time to get your rods out of storage and ready to hit the beach!
