Copepods 101: Everything YOU Need to Know About Pods!

Hi, Teras Pleskin here and welcome back to another episode of TopShelf Aquatics and welcome back to the Calypso Aquaculture Lab. And today, in today's episode, it is my absolute pleasure and honor to be discussing one of my favorite groups of organisms on this planet. Today, we are going to be doing a rough crash course into the world of copapods at large. Copapods, the micro crustaceations that act as the great communicators, the communicators, the agents that mingle in between the micro and macroscopic worlds. So let's discuss copapods. So what exactly is a copapod? A copapod for all intents and purposes is a micro crustation. It is a very very very small organism similar to that of a lobster, a crab or a shrimp. Copapods are very very similar to their relatives, the isopods and the amphipods that we'll be discussing in future episodes. But it should be fully appreciated that they are very much their own class of organisms. And within that class are various different orders of kapods of which there is a tremendous amount of inherent diversity and a tremendous amount of diversity in both the form and function of those copapod species. But as a whole the function of most copod species is just like that of a lobster or a crab just on a much much smaller scale. We can think of what appeals to us humanity about crabs, lobsters and shrimp. They forage on various things all day in the marine environment. They forage on whatever they they can find their prey items and whatever leftover detritus and algae that they're foraging on as they get bigger. And eventually they glean and concentrate all of that nutrition and turn it into beautiful well delicious umami lobster and crab dinner. Kopods do the exact same thing except instead of a human being able to eat a one- pound lobster, it is a microscopic bass or tang larvae that is being able to eat a microscopic kodi, its own tiny lobster dinner, which allows all these very, very tiny microscopic larae to someday glean the nutrition they need to transform into the beautiful titans of the reef that we see. All copods share a general life cycle. Much like a butterfly must first go from an egg, a caterpillar, and then a cocoon before its final adult life form. So does every copod species follow the same general set of life stages. We start off life on the back of mom as a series of eggs. Most copods will hold on to their eggs as a series of clusters kept on their back. After an incubation period, those eggs will then hatch into the first stage of the copod. We know this as the nopus. The noplus can be recognized as one of these small rotating dots that we see on the periphery of this sample I prepared here. So the noplus goes through and then begins to start feeding on phytolanton the like. And much like an ant or any other insect um the copod or another crustaceian goes through a series of molts and every time it molts it slowly metamorphosis. It changes its appearance slowly migrating towards the adult morphology. So after a few molts or instars the noplus will transform into this middle stage. We can see that there's kind of like these weird middle ground things crawling in between the adult tisby benamus copods we have here and the nopi that we see hovering in the periphery. These middle stages are known as the copapodite. This is a weird middle adolescent stage which more closely behaves with the adult ecology but is still not fully sexually competent and is not a fully formed adult. At the same time, there are many, many, many different orders of copods. There is such a diversity of copods that likely new copods will be discovered and their classification will be chopped up and redefined many many times over the next century. But for the most part, we are going to be chopping up and dissecting this early introduction to copods at large uh into three general orders. Now the first order is the order that is most familiar and in my opinion has the most utility for the reef aquarium industry as we know it today and that is the harpecttoids. The harpecttoids are the crawlers. These are the crawling copods the ones that are specialized in occupying various different substrates. They like to anchor themselves with their powerful limbs. You see behind me is some examples of artis venamansis. I think a fantastic harpacttoid that has been domesticated for use in the aquarium industry and also for use in aquaculture. So harpacts in general are associated with substrates, sediments and even more stagnant water ecosystems. Uh tisbes uh enjoy a wonderful distribution worldwide where they can occupy everything from the surfaces of seaweeds and then of course thrive in tide pools as well. Uh we'll see some other features of the harpactoids far more dramatically illustrated in the next species that we'll illustrate. Tigriopus californicus. This is a harptocoid copod which has specifically adapted to thrive in tide pools off of uh the California coast all the way down to Mexico. So harpactoicids the tigropus californicus we can imagine what might be happening on the California coast here. As water splashes over and then recedes, you have very very cold water coming in at 50° and then as it gets uh hit in a tide pool by the sun, we are having that water heat up towards 100° reflecting and then while it's doing that evaporating and increasing dramatically in salinity uh reflecting the ability of herpactoid cop pods such as tigriopus to be able to not only withstand extreme increases in temperature but increase increasingly high spikes in salinity and increased exposure to UV radiation as well. So in general the harpaxoid cook pods are defined by being these crawlers associated with substrate being extremely tough in their environmental conditioning and being adept colonizers of new varied ecosystems. Now the first major drawback when it comes to harpaxicoids at large is the fact that that noplus of theirs is very very very large compared to the adult body size. And for that reason they are relatively unusable when it comes to larva culture. They're a little too big to fit in the tiny tiny mouths of tiny shrimp and tiny fish larae. However, the adult forms because of all these characteristics we've discussed have been extremely helpful when it comes to seeding different nursery systems uh for things such as mandarins and seahorses grown at scale to provide supplemental grazing opportunities and continuously recycle waste products in the system into critian forage. Let's discuss the next order of copods we grow here, the cyclopoids. Now there's some immediate contrasts we see when comparing it to the locomotion and the appearance of Tigriopus and Tisby. Firstly, Apo Cyclops is occupying the water column. It does not have these big charismatic grasping legs to attach to substrates and maneuver them over long periods of time. Rather, Apo Cyclops is kind of like a spaceship peping forward but still occupying water all around it at any given moment in time. This translates into a few different things when contrasting a apocid. Now firstly this means that they are far more attractive when trying to feed things that are filterfeeding zoplankton in the water column versus things that are hunting zop plankton off of substrates. Mandarin dragonets and pipe fish can easily be associated with harpacttoid feeding because they're constantly hunting on various substrates. Whereas something like an MPS coral really needs to feed on zop plankton that's available to it wafting through the water column. And this is where my primary recommendation lies when it comes to the specific application of apoyclops copapods in the reef aquarium hobby. Most cyclopoid copapods have actually been embraced on the freshwater side of things for breeding. Breeding various killifish and various other freshwater ornamental species. Apo cyclops culpods have that same potential utility. Their nopi are much smaller than that of the tis benensis and the tigriopus meaning that they are far more available to some sets of invertebrates and laral fish. Another significant point of contrast between cyclopoid copods such as apocyclops and harpactoicids such as Tisby and Tigriopus is that due to their need to occupy the open water column, apoc far far magnitudes less competent in being able to actively colonize the average aquarium. Within a few hours of dosing, all these cop pods are going to be scattered throughout the system, either consumed by various uh different uh corals, fish, invertebrates, or they are going to be consumed by the filtration. There's simply to too much overturn in the average reef aquarium for these to be used as colonizing agents such as Tisbes. However, their utility lies less in their ability to colonize a reef aquarium and more in their ability to be aquacultured by the average aquarist with minimal technology and minimal cost and minimal heartbreak. This is a species that thrives in a stagnant 5gallon bucket. As long as it is dosed with phytolankton, given a little bit of arration and provided a little bit of illumination, this species can reach high high densities without any meaningful action on part of the aquarist within a few weeks time. Now, this contrasts with let's say a Tisby copod culture, which one would only need to dose one time into the aquarium to have that colonization effort. But at the same time with the Tisbes do not have that same density and open water feeding opportunity that one might need to satisfy the needs of a larger filter feeding uh zop plankton uh occupied tank. The last order of copapods we'll be discussing today are what I refer to as the Cadillac copapods. These are the kenoids. The keninoid copapods take all of the peculiarities of the cyclopoid copod and push them to the extreme. Keninoid copods as a whole occupy more stable open water ecosystems. Keninoi copods are far more represented in big open water ecosystems such as out in the middle of the Atlantic and inside giant pelagic gys. There they occupy large tremendous open spaces. Kenoids are for the most part defined by their need to have much more pristine water quality and a much more specific diet than their relatives in the kenoids and harpacttoids. Species of note include the pelagic tropical copapod parocalisrus. This is a copod which in contrast to apocyclops must eat live microalgae. Unlike a apoyclops, it cannot eat dead microalgae. It cannot eat ciliates. It cannot shop around. Unlike tisbes inopus, it cannot scrape from substrates. If it touches the side of an enclosure or if it touches a different substrate, parvo colanis will be like a spaceship crashing into earth. Thus, in both terms of how it must be housed in a diet that it must enjoy, poveris must be catered to in a very pristine open water environment and fed live highquality marine phytolanton such as tices latia or katosterous muery. So, if they're so fragile that they require specialized vessels, incredibly high water quality, large amounts of water changes, and are very, very specific on the quality of live phytolanton that they must be fed, why on earth would anyone openly care about growing keninoi koopaods? And the answer to this is that the true value of these keninoi koopaods lies within their napli. The napi of keninoid species okopods are extremely small in size even a fraction of that of apocyclops panamensus' nopi eye. Those tiny tiny nopi are not only small but they are extremely profoundly nutrientdense attributed in no small part to the highly specific necessary live feed diet that is demanded by their parents. There's these tiny napi that contribute the golden fats, the probiotics, the pro-enzymes and all those found foundational building blocks which allow the naked fragile freshly hatched larae of everything from tuna to tangs to reef lobsters to able to set up shop to form their intestines to line those intestines with beneficial bacteria. And is within these pelagic patches, these fragile little pastures in the middle of the ocean that all of our favorite reef organisms begin life. Uh with those three different orders of copapods in mind, we will then kind of confront kind of a general question. But what's the best copapod? Well, the best copapod is extremely contextualized within what is your goal? There's so many copods in the world over doing various things that I'm convinced that if you're a technologist or no matter what interest you might have, there could be a copod for you, for that technology, for that application. But for as far as our purposes here at the Calypso Aquaculture Lab, we have three main considerations that we must ask ourselves when we're trying to address what cop pods we're trying to work with. Are we trying to colonize a reef tank? Are we trying to have something that's a continuous source of cleanup crew action at the same time offering continuous source of grazing opportunities to zoplankton feeding fish? Well, then harpacttoids are our bet. Tisbes will colonize and they'll be available to dragonetses. Are we trying to breed something for the very first time? A fragile larae that hasn't been described and we want to give it the best shot that we can to have success to be the first people to breed a tang for the first time. Well, then the kenoids parvo is our bet. And are we trying to marry the two? Are we trying to at the same time not only grow a larae for the first time that's very fragile, but maybe grow lots of larae at a huge density and we don't have the space, the material, and the scale to grow parvo at that at that scale. Well, then potentially apoyclops would be our third greatest option for that specific application. And it is within that kind of mind frame that I'd like all of us to potentially dwell. What is our goal? What are we trying to accomplish? And is there a copapod that we can learn from? A copod that we can embrace and a copod that we can deploy to solve and accomplish that mission. Thank you. Uh we've had lots of fun talking about copods today. I welcome any comments you or questions you might have. Be like a copod and propagate all over that like and subscribe button and we will see you next time at the Calypso Aquaculture Lab. [Music]