proposal
edited
Michael Glander
October 2, 2009
Mortality of Chrysaora fuscescens compared between Kreisel and C…
Michael Glander
October 2, 2009
Mortality of Chrysaora fuscescens compared between Kreisel and Concentrated systems
I. Introduction
Taxonomy of Chrysaoran fuscescens:
Domain- Eukarya
Kingdom- Animalia
Phylum- Cnidaria
Class- Schyphozoa
Order- Semaeostomeae
Family- Pelagiidae
Genus- Chrysaora
Species- fuscescens
Chrysaora fuscescens are commonly-found Sea Jellies, of the family Pelagiidae. They are commonly known as Pacific Sea Nettles. Chrysaora fuscescens can be found in all temperate and tropical seas (www.britannica.com). Chrysaora fuscescens are the typical “Jellyfish” that one may encounter, through sight or sting, while visiting U.S Pacific coastal beaches. All Chrysaora, along with other members of the class Schyphozoa, go through the same life cycle. The main life cycle consists of sexual reproduction, and 5 major stages. After fertilization, a Planula (larva) forms once the female’s eggs have hatched. The Planulae drift with the currents, until they find a solid and good position to implant themselves on (such as a good piece of live rock). From this moment, the Chrysaora begin their scyphistoma (polyp) stage. Sea Jellies are related to corals and anemones (Phylum Cnidaria), so their scyphistoma stage is similar to those of corals and anemones. The scyphistoma generally appears similar to anemones, as it is a cylindrical base with tentacles and a central mouth (Aaron Jeskie). The scyphistomae will eventually begin to strobliate due to environmental conditions, until small, discus ephyrae begin swimming off. At this point, the scyphistomae look like a column of disc-shaped ephyrae, which split off during strobilation (Aaron Jeskie). That leads to the next stage, called the ephyrae stage. The ephyrae stage is the major developmental stage. Eventually the ephyrae will morph into the final stage, medusa. (Aaron Jeskie) Medusas are the final stage, with a bell-shaped dome and tentacles with nematocysts (stinging cells used for defense and to capture prey).
Typically, Sea Jellies are difficult to keep for home aquarists. The problems stem from the consistency of Sea Jellies, in terms of their texture. Sea Jellies require special types of systems, as intake grates, powerheads, overflow boxes, and other parts that may be required for certain systems, can pose problems to Sea Jellies. Sea Jellies run the risk of getting sucked into a powerhead, or clogging up intake grates if they become entrapped. Additionally, Sea Jellies do require currents to move them, as they cannot move effectively under their own power. Fortunately, Kreisel systems help keep currents moving in the water while avoiding the terrible consequences of a Jelly interacting with physical filtration units in the aquarium. Kreisel systems generally have slow moving, circular currents in a ellipse-shaped container, for the purpose of keeping the Sea Jellies moving, but preventing them from becoming trapped or killed by a filtration unit (www.advancedaquarist.com). Jellies should also remain suspended in the water, to avoid infection of abrasions potentially caused by rubbing against container walls. Kreisels are quite expensive, as it is a tedious process to make them. This method is the most common for larger aquariums (www.jellieszone.com). Sea Jellies also require special feeding, as there is very little biological filtration in their systems. To prevent the buildup of harmful nutrients, aquarists will often use smaller amounts of concentrated food rather than larger amounts of less-concentrated food. Sea Jellies are uncommon in home aquariums because of their difficult upkeep, but also because of their toxicity to systems and humans. The majority of Jellies are not reef safe (Julian Sprung).
II. Questions to Answer
What is the best and safest method of transferring ephyrae to their systems from the scyphistomae systems?
What is the best and safest method of transferring ephyrae from their main systems to medusa systems?
Which environmental changes could cause strobilation of polyps?
How can biologists manipulate the environment to cause strobilation?
What are the typical mating signs, if any, of Chrysaora?
How can ephyrae of different species be best identified?
What is the most effective way, in general, to keep Sea Jellies?
III. Hypothesis
If Chrysaora fuscescens are raised in either a Kreisel system or a smaller container with concentrated feedings and more frequent water changes, then the Chrysaora fuscescens in the Kreisel system will reproduce and grow with a lower mortality rate than those in the smaller container.
IV. Design of Research
Chrysaora fuscescens scyphistomae will be kept in Petri dishes submerged in salt water (specific gravity between 1.020 and 1.024) at a temperature around 13°C. The environmental conditions will be changed in the systems in different ways in order to cause the scyphistomae to strobilate. Once ephyrae begin separating from the parent scyphistomae, they will flow into a small collection tank, where they can be transferred to their respective systems (either Kreisel or experimental concentrated system). In the concentrated system, water changes will be performed daily, as will feedings.
V. Schedule
Observations and Lab work will be made/done 1-2 times per week. Feeding will occur daily, as will water changes in the small container.
VI. Supplies Required
- Kreisel system
- Small container (the experimental system)
- Chrysaora fuscescens Sea Jellies
- Brine Shrimp (feeding)
- Microscope (for viewing jellies in ephyrae stage)
- Camera/Filming Equipment
- Equipment used in transfer specimens to aquaculture room
VII. Bibliography
Sprung, Julian. Invertebrates A Quick Reference Guide. Miami, Florida: Ricordea Publishing, 2001. Print.
Watson, Stephanie. "How Jellyfish Work." 22 September 2006. HowStuffWorks.com. <http://animals.howstuffworks.com/marine- life/jellyfish.htm> 26 September 2009.
Jeskie, Aaron. Aquarist II – Tropical Diver Gallery (Georgia Aquarium).17 September, 2009.
Blundell, A., (2004) "Delicatessen Part I: Creating a system for rare and delicate animals” Advanced Aquarist Online Magazine. <http://www.advancedaquarist.com/issues/dec2004/lines.htm> 28 September, 2009.
"Keeping Jellies in an Aquarium." The Jellies Zone. The Jellies Zone, Web. 1 Oct 2009. <http://jellieszone.com/captivejellies.htm>.
Castro, Peter, and Michael E. Huber. Marine Biology. 6th ed. New York,NY: McGraw-Hill Companies, inc, 2007. Print.
October_2009
edited
October presented new opportunities for the study of the Sea Nettles. My first visit to the aquari…
October presented new opportunities for the study of the Sea Nettles. My first visit to the aquarium was really just to get an idea of where I'll be working. I learned about the system keeping the polyps, and how we're going to collect the ephyrae (system pictured here). In November, we will begin manipulating the systems in such a way as to cause strobliation. The problem is, we don't know exactly what causes strobilation in the Pacific Sea Nettles, so we will try changing temperature, salinity, currents, and lighting to get them to strobilate. Ephyrae will then strobilate off of the parent polyp, travel into the overflow tubes, and be collected in the small containers on the left of the picture.
Relating to medusa stages of the Pacific Sea Nettles, I was able to go behind SS6, the main C. fuscescens exhibit, and learn how to sex the medusas. Nao, a biologist who works with the jellies, showed me where to locate the gametes, along with some basic sea jelly nomenclature relating to their body parts. I was able to take video of Nao giving a lesson about the medusas in SS6, relating primarily to their reproduction.
November 2009
edited
November was a developmental month. I spent the month trying to create a new system for the ephyra…
November was a developmental month. I spent the month trying to create a new system for the ephyrae, as the experimental system. With the guidance and excellent help of Aaron and Nao, we developed a third system (non-Kreisel) to house the ephyrae. The system consists of cylindrical filter housing with an air hose along the bottom. The air hose serves as a bubbler to keep the ephyrae off of the bottom, as ephyrae are planktonic by nature, or require currents or other water movement for locomotion. I included a mechanical pencil in the image, as a reference point to help show the size of the system. It is not large by any means, considering we are dealing with small organisms.
{System.jpg}
Upon maturing to the medusa stage, the ephyrae will require movement to a kreisel system. Bubbles from the air hose bubbler could become trapped under the bell of the medusa, which could cause serious problems such as infection from dry tissues, which could lead to death.
In relation to the polyps themselves, I decided to get a better look at them and try to make some observations on growth. In a time span of about three to four weeks, I had noticed an increase in size of certain polyps. The polyps labeled in the rightmost picture had grown to that size, starting at the size of the polyps in the rightmost Petri dish (the polyps are small pinkish dots).
{M.Bio_2.jpg}
In this last portion, I'd like to address/discuss some changes I've made to my experiment. The change in mind is an addition to the main ephyrae study. I wish not only to find out the mortality rates of the ephyrae, but also to find out what causes strobilation in these particular polyps. After speaking with Aaron about ideas on how to get the polyps to strobilate, I thought that it would be beneficial to the overall understanding of Chrysaora fuscescens to attempt to pinpoint which environmental stresses can potentially cause strobilation in this particular group. In general, there are many different environmental variables that can cause strobilation, but by seeing whether or not the same manipulated variable (eg. salinity) works for all polyps in this system, it may help determine the cooperation or if there exists any recognition between polyp colonies.
