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.
Day 2 of the Oyster South Symposium was the final day of presentations and the trade show, but it is also the day of the Shuck and Tell closing ceremonies. Another grey sky day greeted us, but the symposium was still full of oyster enthusiasts and farmers. Day 2’s talks focused more on marketing and the future of oyster farming, including discussion of a new program for Federal Crop Insurance and a panel of chefs discussing “What Chefs Want” when it comes to an oyster. The oyster disco ball also made an appearance, and I was finally able to snap a photo of that beauty!
The Famous Oyster Disco Ball! – Thomas Derbes II
Saturday’s talks started with a reflection of what Oyster South is and what it could be. Oyster South is a 501(c)(3) charitable organization that strives to connect communities and provide resources to support oyster farmers, cultivate thriving communities, and promote healthy waters (Oyster South’s Mission Statement Here). While South is in its name, the scope of Oyster South has become national with visitors and farmers from both coasts coming to collaborate and share stories of their oyster farms. I was able to talk with farmers from all over the USA, from California, Washington State to New Jersey, North Carolina and even Texas where oyster farming is still in its infancy.
After the reflection, we were treated to two awesome panels, one discussing what chefs look for in an oyster and another on making the most out of social media. Every chef has a different view of what they want in an oyster, but consistency and a certain salty yet umami taste came up as something they strive to serve. Social media also plays a major role in oyster farming and distribution. I remember when I was an oyster farmer, I quickly had to learn how to do social media as this was the best way to advertise and promote your product. Most people have Instagram or Facebook now-a-days, so being able to post your story and availability was always helpful in increasing your following and sales.
Talking About What Extension Can Do For You at Oyster South Symposium – Thomas Derbes II
After the lunch break, we had a Three-Minute Tech Talk Session. We heard from graduate students that needed input from the oyster community on their research topics, oyster farm innovators discussing their newest and greatest creations to help oyster farmers, and I was even given the opportunity to talk about what extension can do for oyster farmers. After the tech talks, we heard about the federal crop insurance program for oyster farmers, as well as a great talk from Julie Qiu (a well-known oyster blogger, advocate, writer, and founder of the Oyster Master Guild) on oyster stewardship and how important it is to oyster consumers and the oyster industry. Beth Walton, executive director of Oyster South, closed out the talks with Oyster South Looking Forward, and the future of Oyster South and oyster farming is very, very bright.
Before the Shuck and Tell, I was able to grab a quick “linner” at an incredible restaurant named Cochon. I had previously worked with a chef that came from Cochon, and his stories were the reason I made a reservation. The food in New Orleans is top notch, and Cochon was the cherry on top of a great gastronomy tour.
When it comes to oyster parties, the Shuck and Tell is the ultimate oyster experience. Farmers from all over got together to shuck their product and tell their story of why they oyster farm and the story of the oyster being shucked at the wonderful Southern Food and Beverage Museum (aka SOFAB). I was blessed enough to jump in and help shuck for some passionate oyster farmers and learn more about their farms and history. A relatively new oyster farmer at Salt Revival Oyster Company arranged for a second line to come through SOFAB, and it was an incredible way to cap off a great Oyster South weekend. The Coalition to Restore Coastal Louisiana was there to make sure all shells were recycled and used for future restoration projects.
Shucking With Salt Revival Oyster Company at the Shuck and Tell at SOFAB – Thomas Derbes II
The 2024 Oyster South Symposium was definitely one for the record books. The turnout was fantastic, and the camaraderie and collaboration between oyster farmers, researchers, and enthusiasts was a sight to behold. A major thank you to Bill and Beth Walton for always putting on an incredible symposium, and a big thank you to all the farmers who took time out of their busy schedule to share their oysters and stories. The Oyster South Symposium is an annual event, so keep your eyes peeled for the next symposium. I hope to see you at the next one in 2025!
The Second Line To Close Out Oyster South Symposium – Thomas Derbes II
This year, the non-profit organization Oyster South held their annual Oyster South Symposium in the Big Easy, aka New Orleans. First stop was the Director’s Welcome at Sidecar Patio and Oyster Bar Thursday night. Oyster farmers, researchers, distributors, educators, writers and fans from all over USA were treated to New Orleans favorites like red beans and rice and jambalaya, but the star of the party was inside the bar area underneath a disco ball oyster. I wish I had taken a picture, but the lure of oysters from the Gulf, East, and West Coasts held my attention. Being able to jump coasts from oyster to oyster was quite an experience, and to have them freshly shucked right in front of you with a knowledgeable shucker took it over the top.
An Awesome Oyster Bar Selection at Sidecar Patio and Oyster Bar – Thomas Derbes
Friday we were greeted with gray skies, but you couldn’t tell from the vibe inside of the Contemporary Arts Center. When you walked in, you were immediately introduced to the trade show wall to wall with oyster equipment and other oyster related things. Once through the trade show, you could take a seat and listen to a plethora of oyster talks. We listened to reports of oyster mortality and the intensive efforts being taken to address this issue, a panel of farmers discussing how their peers can get an alternative source of income from catering and tours, oyster hatchery and farm research updates, and stories of oyster farmers and chefs on what an oyster means to them. The future of oyster farming looks very bright, and researchers are doing great things to help build the strength and resiliency of oyster farming. After the talks, we visited the trade show again and caught up with friends, old and new.
Distinguished Panel of Oyster Farmers Discussing Alternate Income Opportunities – Thomas Derbes
Tomorrow brings more talks, and the amazing Shuck and Tell closing ceremonies. Stay tuned for a Part 2 and Overall Thoughts.
I felt it this morning. That first bit of humidity in the air. That sign that it might indeed be time to move my tropical plants back outside and consider digging in my raised beds this weekend. My seed catalogs are dog-eared, and my local garden store is flush with seedlings. But then I remember, the squirrels, oh how I loath them. They love to thwart all my soil-based gardening attempts, despite my feeble attempts to guard my crops. My option? Return to one of my first loves, aquaponics.
I have been practicing aquaculture as a career for over 30 years and aquaponics for about 15 of those. Aquaponics is a unique food production method that combines aquaculture with hydroponics, or the raising fish with raising plants in a typically soilless system. The fish produce waste nutrients that bacteria in the system convert into a form that the plants can utilize and extract from the water, thereby cleaning the water for the fish. The process is a bit more complex than that and I can spend all day talking about it but that is the short version. Aquaponics can be done in small homemade systems or very large commercial systems. There are hundreds of designs online and you can spend hours online viewing what others have done. My recommendation is to start with the research-based information that you can get for free from colleges and universities and then explore once you are confident in the basics.
In Florida, many types of fish and plants have been successfully grown in aquaponics, however, there are some legal restrictions on some species of fish, so be sure to check before deciding on what fish you will grow. I chose to grow catfish in my system and over the years produced multiple crops and varieties of lettuce, bok choy, pak choy, cherry tomatoes, Swiss chard, basil, turmeric, and snow peas; the sky is the limit.
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
And it’s a good thing! Green gill oysters are prized in the oyster community. In the Carolinas and Northern France, green gill oysters are a seasonal, cherished crop and a product of the saying “You are what you eat!” The phytoplankton, Haslea ostrearia, is the typical culprit, and their distribution is measured by direct observation from plankton tows or the occurrence of green-gilled oysters. The exact distribution is unknown, but there are reports of H. ostrearia throughout the Atlantic, Pacific, and Indian oceans. Haslea ostrearia is a beautiful pennate diatom that contains a water-soluble blue pigment known as marennine (More Here). Marennine’s production is stimulated by long photoperiods, blue light, and high light/low cloud weather. It can also be released into the water and into the flesh of organisms (typically oysters) that consume them.
Fresh out of the water Grayson Bay Oyster with green gills! – Brandon Smith, Grayson Bay Oyster Company
Pensacola Bay, and surrounding areas, had a pretty mild fall in terms of rainfall, and the bays have turned a beautiful green-blue hue as the bays have risen in salinity and phytoplankton typically found in the Gulf of Mexico were able to survive. Brandon Smith, owner of Grayson Bay Oyster Company, was out working his farm January 7th, 2024, and sent a text to me saying “take note of the green gills,” and I was very shocked and happy to see actual, green-gilled oysters in our local waterways. He graciously harvested a few dozen to examine (and let me taste test), and I was able to confirm the presence of green gills in the oysters. After further research on H. ostrearia, it seems as though the pennate diatom made it into our bays and is the culprit of this wonderful surprise.
A local Grayson Bay Oyster displaying green-gills – Thomas Derbes II
When I shucked my graciously donated oysters from Grayson Bay, I was reminiscing on the first time I came across green-gilled oysters. The first batch of green gill oysters I ate came from an oyster farm in North Carolina called N. Sea Oyster Company. Their green-gilled beauties “Divine Pines” were requested by a wedding I was catering for, and I was able to slurp down one to get talking and tasting notes. The seasonal Divine Pines offered a sweet yet salty taste and became one of my favorite out-of-area oysters to serve at events and to personally consume. While beautiful, the green-gilled oysters are usually only found in the fall/winter months. These green-gilled Grayson Bays were very comparable and offered a salty yet very sweet and minerally finish. The H. ostrearia is responsible for not only the green gills, but the sweet tasting notes, and I highly recommend adding any green-gilled oyster to your fall/winter raw bar selection.
References:
Turpin, Vincent & Robert, J-M & Philippe, Goulletquer & Massé, Guillaume & Rosa, Philippe. (2008). Oyster greening by outdoor mass culture of the diatom Haslea ostrearia Simonsen in enriched seawater. Aquaculture Research. 32. 801 – 809.
