Urgent advice needed

[qiazopus]

Hi all, I've described some problems I'm facing with the octopus.

They are sick and I don't know why - no one has bred this species (Octopus berrima) successfully so I'm not sure if it's because this species is more fragile or that I'm doing things wrong.

The system is completely flow-through set to about 4-6L/hour and I've been cleaning the excrements once a day. There has been plenty of poop and shed skin.

Please read it here with photos: https://tonmo.com/threads/octoproofing-glass-tanks.47157/page-2#post-239377

 

[tonmo]

sorry you are dealing with this @qiazopus ... I wish I had guidance; hoping an expert here can offer some insights.

 

[pkilian]

You could try doing some water chemistry on the system. I would be surprised if the water quality was poor considering its a flow-through system but it doesn't hurt to check. Also, what is the pH, salinity, and temperature on the systems? You could also check phosphates and put some cuprisorb in the system to see if there is any copper in the water, as well as some carbon if possible.

It's hard to tell exactly what is going wrong with the system until we can get some more diagnostic information.

 

[robyn]

Honestly from what you reported on the other thread it sounds like the animals got hot and stressed during collection and they are dying because of the extended stress. I think it's less likely to be water quality if the facility (is this at SIMS? I don't recall exactly where you are) is holding other animals in flow-through without problems. The pictures your posted look like large, borderline senescent animals that are going to be very susceptible to extended periods of stress. I'm not sure if you have any left from your post on the other thread, but I would recommend euthanasia of any of them looking that poor, and starting over when you can collect in cooler conditions.

 

[robyn]

Also is the flow-through rate you listed (4-6L/h for the whole system) correct? That seems very slow to me and I wonder if the animals are accumulating chemical waste in their enclosures. For reference, I have an octopus system that turns water in each enclosure at ~750mL/min.

 

[qiazopus]

Sorry I don't know how I completely missed your replies but thank you!

OctB unfortunately passed in the following week after I posted it on the other thread, the white patch expanded over most of her mantle...

There are 2 octopuses that are still with me and have been doing well since - one has been feeding on crabs while the other that also laid eggs ate 2 crabs in the middle of brooding. It's been over a month and the eggs still look the same, so I suspect they're unfertilised.

So the water chemistry is probably OK since the water source and treatment is the same for all tanks. I do agree that the main contributing factor is the heat stress. Water temperature at collection site and the facility (unfortunately I'm not at SIMS, this is at SARDI in South Australia which is 10h away from the collection site) are the same, salinity are quite different. I am heading for a second trip (hopefully the last) to get more octopuses but with a modified method this time:
- I bought thermal insulated bags to keep each bucket of octopus cool
- I made 20x20cm ice blocks to keep 1-2 of them in each bag
- I'm hiring a van (Toyota Hiace) that is completely air-conditioned throughout, I'm not sure how powerful the AC is that's why I have the ice blocks as an additional measure
- Also checked the weather and looks like it'll be pretty cool at 18degC and sea temp is currently 16degC
- I also have aerator for each octopus
- Also bringing 720L worth of coolers to store spare seawater for on-the-road water change + for acclimation
- I'll acclimate them overnight using a drip rate of about 3.9L/h (fast, individual beads of water almost connecting into a stream)

The tanks here are pretty small at 25L but the actual amount of water is about 22L. The flow rate for the 2 octopuses with me is at about 5.5L/h so the tank should have cycled 6 times over 24h. However as this is an ocean warming experiment, heaters in some tanks (tested without any live animals) can't keep up with maintaining higher temperatures and the lowest rate was at 720ml/h i.e. only 79% of the tank is changed over 24h - not sure if that's okay?

 

[robyn]

I think that flow rate is much too slow, personally, given the fairly small enclosure size; perhaps you need some more powerful heaters to permit a faster flow rate. A turnover rate of 6 per 24h is very slow; the recommendations we go by here state 6-10x per hour for systems less than 1000 US gallons.
You new transport plan sounds good! God luck with your next expedition!

 

[qiazopus]

Thank you @robyn! Just wanna add an update here that my latest transport plan has went extremely well - 21 out of 22 octopus made the trip and have been in my tanks for almost a month now, most of them have become octomoms ^_^ I've also followed your advice in increasing the flow rate to the maximum!