Copepod Culturing – Harpacticoids
This document is a rough draft and will be updated soon, I plan to add pictures and clean it up a touch as well as add two supplemental documents targeting Calanoid culture, and finally Phytoplankton culture.
Items Needed:
Heaters (one for each culture, optional but preferred)
Air Pump (you may need to shop around for one capable of enough flow)
Gang Valve (or air manifold with enough outlets to run desired amount of cultures)
One way air valve / filter (one for the pump and one for each culture preferred)
Rigid Air Tube (thinwall, pick up a couple of strips)
Vessels (Concrete Tubs work great for this, look for vessels that are shallow, wide and long harpacticoids love to rest on the bottom surface)
you can get the concrete tubs like this:
Shelf or rack for tubs (Adjustable metal shelving works best as you can size shelves for the tubs)
5 shelf metal that I prefer:
cheaper less configurable plastic option:
Normal output flourescent strip lights (not required but preferred) numbering the total shelves if using shelving unit above a two foot strip light or a “puck” over each tub works well.
Strip light:
pucks these now available at Home Depot:
http://www.environmentallights.com/categories/1301_2368/cfl-under-cabinet-pucks
The pucks work great as they are low wattage and can be mounted using double sided stick tape, since they chain on one circuit you don’t have to meddle with too many cords. I have just recently switched to these.
Light timer (only needed if you utilize lights) I prefer the intermatic digital type but this is purely up to you, your light cycle will run on the average 16 on and 8 off.
White plastic piece (this can be a piece of eggcrate, or any flat piece of white plastic measuring at least ½” square) This will rest at the bottom of the tub so that you can shine a flashlight on it and see the tint of the water for food judgement.
Source of food!! This one is where it all gets interesting. You will need to choose your source of marine phytoplankton, I have had excellent luck with the instant algae from reed mariculture but prefer to grow my own live phytoplankton. I utillize three live species, Nannochloropsis as a primary, Isochrysis to increase HUFA and typically either Thalasiosira or Tetraselmis depending on which I have on hand at the time. I always keep a jug of Reed’s Nannochloropsis in the fridge just in case my cultures crash or run thin, this gives me supplemental food in the event of an emergency. For small scale culturing it is often cheaper to utilize Reed’s products than it is to grow your own. If you are going to be culturing on a larger scale or prefer the live feeds look for my Phytoplankton primer and go from there. A good source of live cultures is Florida Aqua Farms Putting it all together!
Setup:
Naturally as a first step you will want to assemble your shelving. I prefer the metal shelving as I can move the shelves down a bit increasing how many cultures I can fit in a smaller space. I typically space shelves around 9-10 inches apart as I remove the tubs for work but in general this method allows you to keep 5 cultures in a 3 ft by 2 foot space, pretty nice density.
Mount your pucks or strip lights to the bottom of each shelf above your cultures. We do not need nor want very intense light but having a light cycle helps to recreate a more normal habitat. If using the strip lights which are a touch heavier than the pucks you may want to find some short screws to attach them with. I have had great luck with a commercial grade double stick tape for mounting both the strip lights (lots of tape) and the pucks (not a lot of tape). It’s a good idea to mount the light with the shelf top off, and set something with a little bit of weight on top of the light for a few hours to help the tape to hold.
Salinity is a judgement call for most but I have had best luck around 1.019-1.022, depending on species this can matter much more. I am assuming either Tigriopus Californicus or Tigriopus Japonicus for this article. You may want to do some research on a particular species. I prefer to keep my cultures around the high mark of 1.022 as I want to reduce shock when feeding.
Fill the tubs to a desired level that you can still manage to move them about without spilling. Harpacticoids prefer surfaces to rest on and are not so much in the water column, the wide tubs provide a lot of this without needing to fill very high so I typically keep this level about half way.
Set your pump above the cultures if at all possible, this can be done by mounting it to the wall, placing it on a shelf above, or using a box or some sort of platform on the top shelf to get the pump above the top culture. Use zip ties or velcro strips to hold the airline and air manifold to the shelving for cleanliness. Run airline from the pump through a one way air filter, then to your manifold. From each outlet on the manifold run an airline down to each culture (adding a filter to each of the airlines from the manifold is a good idea to help avoid cross contamination should a culture get contaminated). Attach the airline to a stick of rigid and place the end in the water.
The tubs often have holes along the rim that you can use to attach your strip with a zip tie. Often I will use a lighter or heat gun to gently heat a strip in the middle bending it at a 90* angle to push the airflow more to the center of the tub. Since smaller bubbles get trapped within the copepods carpace and can cause mortality we do not use an airstone. Open your airvalves and set the bubble rate to a low to medium flow the water should bubble up above the rigid and slowly circulate but not look as if it is “boiling”. We merely want gas exchange at the surface and some flow to keep detritus in suspension and don’t want to shake the poor little guys up so much so avoid keeping the airflow really high.
If you should decide, drop a small 25w or 50w heater in each tub, while there is much argument to what temperatures are preferred for each species I have found that keeping a stable temperature is key in production, the goal here is to avoid fluctuation rather than to heat the culture. I generally keep my cultures around 72-76*F. Most Tigriopus harpacticoids are a temperate species but also a tidepool species, they do well in temperatures between 65* and 80*, temperature levels higher than 75* will result in more male offspring but not enough to affect cutlure production.
Add your preferred food source, using a flashlight and watching the white plastic at the bottom to tell how dark your tint is, the water should tint a medium green. You will want to keep the water a light to medium green to ensure there is always food. If using live phytoplankton the algae will continue to grow in a lit culture, while it will not grow as fast (not to mention will be consumed over time) it will help to reduce feeding needs as well will aid in nutrient removal and keeping water quality up.
At this point you can add your culture stock, monitor the cultures over time and harvest when you notice high population count (I typically siphon 10ml samples from the bottom and do counts under a 20x dissection scope) Because this article is geared at the hobbiest I will simply say “use your best judgement” you can harvest quite often without adversely affecting population but the best practice is to harvest in cycles from each culture.
I tend to rotate my harvests between cultures, so 5 cultures, harvesting one each week will give you a 5 week regeneration time in each culture. Harvest by siphoning the culture with airline tubing, it is a good idea to strain the harvest through a 53 micron sieve to avoid getting poor quality culture water into your target tank.
If you are harvesting for nauplii or particular sized plankters (for larviculture, etc.) you will want to invest in multiple size seives to separate the animals. Florida Aqua Farms has a great selection of these collectors and they can easily be stacked. After harvesting, top off your culture, check and maintain food and get on with your day!
Advanced Tip – the enteral feeding pump:
Typically, food over time verses food all at once is a better method (in fact almost all the time!). Slowly adding food source to your cultures rather than adding in a batch will help to maintain water quality, reduce mortality due to food running out, and helps to maintain salinity and other such environmental fluctuations.
I achieve this through the use of multiple Enteral Feeding pumps. You can use dosing pumps or other periostatic pumps to move algae cultures into the target cultures but I have found through the use of ebay that Enteral Feeding pumps are cost effective and give a great level of control over the rate at which I add my algal cultures.
Look for models where you can set the rate of ml per hour, as well as set a stop volume (as you will need to refill the bags). Do an ebay or google search on Enteral Feeding pumps and you will find a ton of options, I’ve found the Compat models work very well and can be purchased in lots of 5 or so for around $200.00 Make sure and pick up plenty of bags (cases of 30 run around $100) and flush the bags often.
When using the enteral method I hang my bags in front of a strip light on the same cycle as the copepod cultures to maintain algal growth. This ensures that my live feeds are still live and hopefully still in the most nutritious logarythmic state. Since using this method I have had excellent success at maintaining water quality and keeping my zooplankton cultures in a state of high reproduction. I use these pumps to administer zooplankton cultures to my larval tanks as well and have found their uses to be almost indespensible in my hobby.
Adjustment, etc.:
Bear in mind this is more of a rough draft and I will be editing it later to add, I will also be adding a Calanoid method in a separate document. If Calanoids are your thing you can easily use this same method by adjusting the Vessel shape and size. Calanoids prefer the water column so taller vessels work better. I use Sterilite snapware containers for my calanoid cultures, while smaller vessels I can fit many of them in a small space using shelving that is less deep.
Enjoy and experiment!!! ~~JRC
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