DIY copepod set-up not working

[michi_copes]

Hello everyone! I am new to this forum but I have been perusing for a while but I made the jump to finally make an account I have been having a hard time keeping a steady copepod population going and I am trying to pinpoint what is going on.

Any help or insights would be deeply appreciated!

To give some brief background:

• I am keeping thousands of copepods alive. I collected these off the coast of New Jersey using a plankton tow. I then sorted these to have only my species of interest, which is Acartia tonsa.
• I am keeping these animals in temperature controlled incubators set to 18°C.
• These animals are housed in food-grade containers I bought on Amazon: Amazon product. I first place them in very hot water (~50°C), then leave them soaking for one week and then let them air dry prior to first use.
• I keep no more than 1,000 individuals/3 L of artificial seawater (ASW).
• I make my ASW with hw-Marinemix Professional Salt Mix, and make it with UV sterilized water. I add it at exactly 30 ppt in each tank.
• Each tank has its own airline and stone, connected to a manifold set up to diaphragm air pump (Jehmco DAPMH8).
• The incubator has a 12 hour light:12 hour dark cycle.
• The light conditions in each incubator are 200-700 lux.
• I have four light strips attached to the door of the incubator. These are the ones we are using: Amazon product.
• I feed each tank ~100 mL of Rhodomonas twice a week -- when I look at the animals under the microscope, I see their guts are red with algae.

I collected >10,000 individuals last month, and as of today I have ~130 adults left. I am unsure what we are doing in our set up that is causing this level of mortality. Right now, I am thinking it is one of two things:

1. Something about our handling is stressing them out
2. Something about our filtering process is causing issues

It was recommended to me to DIY my own filter cones to separate adults from nauplii/eggs. This is because I have understood (1) adults can eat their young, and (2) adults can mate with their offspring. As such, I made cones by buying food grade tupperware containers, cutting the bottom off with an Exacto knife, and hot gluing on a 60 um mesh (to catch nauplii/eggs) or a 200 um mesh (to catch adults). Then, per recommendation, I placed these in hot water and leeched them, identical to how I do it for my tanks.

Every week, I check on all my tanks to see if any nauplii have emerged. If so, I pass my culture through a 200 um mesh cone to catch adults and a 60 um mesh cone to catch the nauplii. These two cones are then quickly rinsed into 1 L cups with a squeeze bottle filled with 30 ppt ASW. I take a subsample of these cultures to then inspect under the microscope. After checking on these animals, I gently place them into new tanks, filled also with 30 ppt ASW.

When we do a weekly water change, we similarly pass the full culture though a 60 um cone, which we then rinse into a new tank with 30 ppt ASW.

I am curious if:

1. The hot glue used to make our filter cones could be toxic to our animals -- this is my prime concern.
2. I should switch as much material as possible to be glass, to prevent potential plastic leeching or toxicity -- I am thinking this may be a potential source of contamination primarily from the tanks, but maybe unlikely because I am using food-grade containers.
3. Separating the adults and nauplii with my cone set up is damaging or worst, killing them.

I am happy to share any further specifications/pictures of my set-up and procedures, if useful. I am extremely grateful for any first thoughts anyone may have Thank you in advance!

 

[Fish Fan]

Hello, new friend!

I don't have a great answer for you, but I'd like to bump this so other R2R members will see it

#reefsquad

 

[i cant think]

Hello everyone! I am new to this forum but I have been perusing for a while but I made the jump to finally make an account I have been having a hard time keeping a steady copepod population going and I am trying to pinpoint what is going on.

Any help or insights would be deeply appreciated!

To give some brief background:

• I am keeping thousands of copepods alive. I collected these off the coast of New Jersey using a plankton tow. I then sorted these to have only my species of interest, which is Acartia tonsa.
• I am keeping these animals in temperature controlled incubators set to 18°C.
• These animals are housed in food-grade containers I bought on Amazon: Amazon product. I first place them in very hot water (~50°C), then leave them soaking for one week and then let them air dry prior to first use.
• I keep no more than 1,000 individuals/3 L of artificial seawater (ASW).
• I make my ASW with hw-Marinemix Professional Salt Mix, and make it with UV sterilized water. I add it at exactly 30 ppt in each tank.
• Each tank has its own airline and stone, connected to a manifold set up to diaphragm air pump (Jehmco DAPMH8).
• The incubator has a 12 hour light:12 hour dark cycle.
• The light conditions in each incubator are 200-700 lux.
• I have four light strips attached to the door of the incubator. These are the ones we are using: Amazon product.
• I feed each tank ~100 mL of Rhodomonas twice a week -- when I look at the animals under the microscope, I see their guts are red with algae.

I collected >10,000 individuals last month, and as of today I have ~130 adults left. I am unsure what we are doing in our set up that is causing this level of mortality. Right now, I am thinking it is one of two things:

1. Something about our handling is stressing them out
2. Something about our filtering process is causing issues

It was recommended to me to DIY my own filter cones to separate adults from nauplii/eggs. This is because I have understood (1) adults can eat their young, and (2) adults can mate with their offspring. As such, I made cones by buying food grade tupperware containers, cutting the bottom off with an Exacto knife, and hot gluing on a 60 um mesh (to catch nauplii/eggs) or a 200 um mesh (to catch adults). Then, per recommendation, I placed these in hot water and leeched them, identical to how I do it for my tanks.

Every week, I check on all my tanks to see if any nauplii have emerged. If so, I pass my culture through a 200 um mesh cone to catch adults and a 60 um mesh cone to catch the nauplii. These two cones are then quickly rinsed into 1 L cups with a squeeze bottle filled with 30 ppt ASW. I take a subsample of these cultures to then inspect under the microscope. After checking on these animals, I gently place them into new tanks, filled also with 30 ppt ASW.

When we do a weekly water change, we similarly pass the full culture though a 60 um cone, which we then rinse into a new tank with 30 ppt ASW.

I am curious if:

1. The hot glue used to make our filter cones could be toxic to our animals -- this is my prime concern.
2. I should switch as much material as possible to be glass, to prevent potential plastic leeching or toxicity -- I am thinking this may be a potential source of contamination primarily from the tanks, but maybe unlikely because I am using food-grade containers.
3. Separating the adults and nauplii with my cone set up is damaging or worst, killing them.

I am happy to share any further specifications/pictures of my set-up and procedures, if useful. I am extremely grateful for any first thoughts anyone may have Thank you in advance!

I can’t help with this exact species of Copepod but I do culture Tigriopus californicus.

My first thought would be, what are the levels of ammonia and such in the containers you use? If you don’t have anything in the container and it’s just the water, phyto, and copepods, you’ll get ammonia and phosphates building up.

Now, I know this may sound odd but have you tried adding in some rock as a filtration system? this will help combat the ammonia and other issues, but also Copepods don’t just eat phyto, they eat certain bacteria like Cyano and Diatoms. You may find your copepods don’t get enough of a varied diet and they become quite weak quite easily.

Your containers sound pretty much identical to my setup for T. californicus, just without any rock/dead coral skeletons or macroalgae to munch on and hide within.

Here’s a closeup of my Californicus containers and one of the whole containers :)

 

[michi_copes]

I can’t help with this exact species of Copepod but I do culture Tigriopus californicus.

My first thought would be, what are the levels of ammonia and such in the containers you use? If you don’t have anything in the container and it’s just the water, phyto, and copepods, you’ll get ammonia and phosphates building up.

Now, I know this may sound odd but have you tried adding in some rock as a filtration system? this will help combat the ammonia and other issues, but also Copepods don’t just eat phyto, they eat certain bacteria like Cyano and Diatoms. You may find your copepods don’t get enough of a varied diet and they become quite weak quite easily.

Your containers sound pretty much identical to my setup for T. californicus, just without any rock/dead coral skeletons or macroalgae to munch on and hide within.

Here’s a closeup of my Californicus containers and one of the whole containers :)

Thanks for your insights! We do not have any rocks/dead corals in the tanks, but that is an easy fix.

We have not been monitoring the ammonia and phosphate levels in the tanks. How fast could these build up? We do a full water change in all our tanks once a week, with fresh ASW.

How do you suggest to add macroalgae to your tanks? Do you add it with their food, or do you place a few large pieces in the tank and replace these once these are eaten?

Regarding the cyanobacteria and diatoms, do you also seed these into the tanks? I presume you also use ASW for your set up.

Thank you again, really appreciate it!