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#1 2017-08-16 15:37:17

Oldfart1939
Member
Registered: 2016-11-26
Posts: 1,598

Tilapia

I'm starting this thread because aquaculture of fish has been mentioned elsewhere, but no one picked up on it as a separate topic. I know very little about these popular fish, other than they are found nearly worldwide and are said to be tasty.

I'm just guessing, but there's a high probability that their fertilized eggs would survive either deep refrigeration or possibly cryogenic treatment with (liq)N2. This would be a very interesting system to incorporate as a means of generating intrinsically nutritional watering stock for the garden activity, since the aqueous by-product of feeding fish is ultimately nitrogen enriched by fish shit. In a way, this might be the best way for the colonists to get a highly proteinacious dietary component before chickens. Yeah, I know--someone will suggest a bacterially produced protein that "tastes just like prime rib--but isn't." There isn't any substitute for the real thing, when meat (beef, pork, and lamb), poultry, and fish are concerned.

So...here's the challenge: we need references on pond-raised Tilapia, the entire life cycle and interval from which fingerlings are hatched up to mature size. The fish guts would also make excellent fertilizer, as in the American Massachusetts Bay pilgrim stories.  Plymouth Rock and all the associated popular mythology. Also, whether the fertilized eggs could survive cryogenic freezing or how long could the survive in a near freezing refrigerated environment.

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#2 2017-08-16 16:18:56

IanM
Moderator
From: Chicago
Registered: 2015-12-14
Posts: 275

Re: Tilapia

For the pond-raised fish, apparently they can grow up to 1 lb in 240 days (https://lakewaytilapia.com/Tilapia-Feeding-Guide.php), although that same source says that a couple of weeks are needed for egg incubation. Assuming that one person eats 3 lb worth of whole fish (I don't know how much meat a 1 lb fish yields), that would mean a person would need to eat 3 fish a day, or 1,095 fish per earth year. According to the source a school of 100 fish would need on average 50 g/day of feed for the first 28 days, 120 g/day for the next 24, and 250 g/day for the last 142. Bear in mind I am eyeballing these values from the tables given. This gives a total of 39780 g of feed for a school of 100 for the total growing season, and multiplying that by 11 gives 437.58 kg of feed needed in total for each person fed exclusively on tilapia.


The Earth is the cradle of the mind, but one cannot live in a cradle forever. -Paraphrased from Tsiolkovsky

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#3 2017-08-16 16:32:39

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 15,597

Re: Tilapia

Other than some fish smell strongly I know nothing really about them other than its a good excuse to get away from the hustle and bustle of lifes many stresses.

Tilapia Fish Farming

Tilapia has taken an important role in the commercial fish farming business sector. Almost all types of people like tilapia recipes like baked tilapia to eat and there are no man who does not like tilapia.

Do not know never tried them...

http://fishfarming.com/tilapia.html

Critical environmental parameters that must be properly managed include dissolved oxygen, ammonia, nitrites, and carbon dioxide. Other important parameters to control within the fish productoin system include nitrates, pH, and alkalinity.

https://en.wikipedia.org/wiki/Aquaculture_of_tilapia

In some regions the fish can be raised in rice fields at planting time and grow to edible size (12–15 cm, 5–6 in) when the rice is ready for harvest. Unlike salmon, which rely on high-protein feeds based on fish or meat, commercially important tilapiine species eat a vegetable or cereal-based diet.

Tilapia raised in inland tanks or channels are considered safe for the environment, since their waste and disease is contained and not spread to the wild

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#4 2017-08-16 18:04:03

louis
Member
From: UK
Registered: 2008-03-24
Posts: 4,634

Re: Tilapia

I don't think you realise the monumental task of aquaculture on a planet like Mars. On Earth water runs freely, on Mars it does not. That means you have to apply a huge amount of energy to the task.

Aquaculture is a really dangerous procedure unless you have copious amounts of fresh water to bascially sluice away your fish shit. If you don't you will have a germ farm on your hands that can infect humans as well as killing off all your fish stock.

On Mars it would mean you would have to expend huge amounts of infrastructure and energy on melting and transporting water ice and then ensuring it was sluiced away and didn't accumulate outside your aquahub.

Why bother? If you want flesh to eat that badly, take along a few guinea pigs. Or even more sensibly, just import it from Earth.

As for your dismissal of meat replacement technology we are already at a stage where people find it hard to distinguish between a real meat burger and a replacement (vegetarian) meat burger (BTW I mean comparing with proper burgers, not the insipid MacDonalds burgers). The replacement techology is working at a molecular level (and also giving you the full sensory experience). I am not claiming they are there yet but they are probably 80% of the way - ie could fool 8 out of 10 people. Beyond that you have the real meat alternative of meat grown from stem cells which will also become increasingly relevant as scientists learn how to stress the "muscle" tissue to replicate real meat.

You say there isn't any substitute for the "real thing". Is a MacDonald's burger "the real thing"?  Sure doesn't taste like any animal I know. But billions of people on planet Earth love them.

Oldfart1939 wrote:

I'm starting this thread because aquaculture of fish has been mentioned elsewhere, but no one picked up on it as a separate topic. I know very little about these popular fish, other than they are found nearly worldwide and are said to be tasty.

I'm just guessing, but there's a high probability that their fertilized eggs would survive either deep refrigeration or possibly cryogenic treatment with (liq)N2. This would be a very interesting system to incorporate as a means of generating intrinsically nutritional watering stock for the garden activity, since the aqueous by-product of feeding fish is ultimately nitrogen enriched by fish shit. In a way, this might be the best way for the colonists to get a highly proteinacious dietary component before chickens. Yeah, I know--someone will suggest a bacterially produced protein that "tastes just like prime rib--but isn't." There isn't any substitute for the real thing, when meat (beef, pork, and lamb), poultry, and fish are concerned.

So...here's the challenge: we need references on pond-raised Tilapia, the entire life cycle and interval from which fingerlings are hatched up to mature size. The fish guts would also make excellent fertilizer, as in the American Massachusetts Bay pilgrim stories.  Plymouth Rock and all the associated popular mythology. Also, whether the fertilized eggs could survive cryogenic freezing or how long could the survive in a near freezing refrigerated environment.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#5 2017-08-16 18:20:53

Oldfart1939
Member
Registered: 2016-11-26
Posts: 1,598

Re: Tilapia

IanM-

The use of fish as a portion of the diet would be to give some alternative to the otherwise mostly Vegan diet. I'm not proposing that we eat nothing but fish, so a 6 oz. to 8 oz. portion several times a week--or even only several times a month--is where this would be directed. A single 1 pound Tilapia should provide that size portion for one person--possibly enough for each person to have 4 oz. and serve 2 individuals from a single fish.

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#6 2017-08-16 19:07:51

Oldfart1939
Member
Registered: 2016-11-26
Posts: 1,598

Re: Tilapia

Holy moley! As anything else that initially appears simple on the surface, the culture of Tilapia seems to be quite an undertaking in order to do it right. I found the following article, and there are other internal links contained therein:

https://lakewaytilapia.com/How_To_Raise_Tilapia.php

It almost make chicken ranching seem tame by comparison. That said, a 1 oz. fingerling can grow to a 1 pound table weight fish in 4 months.

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#7 2017-08-16 19:17:03

louis
Member
From: UK
Registered: 2008-03-24
Posts: 4,634

Re: Tilapia

I think that just confirms the truth of what I said about aquaculuture - doable but difficult on Earth...extremely difficult and only doable with expenditure of huge amounts of energy on Mars.

Oldfart1939 wrote:

Holy moley! As anything else that initially appears simple on the surface, the culture of Tilapia seems to be quite an undertaking in order to do it right. I found the following article, and there are other internal links contained therein:

https://lakewaytilapia.com/How_To_Raise_Tilapia.php

It almost make chicken ranching seem tame by comparison. That said, a 1 oz. fingerling can grow to a 1 pound table weight fish in 4 months.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#8 2017-08-17 07:56:01

Terraformer
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From: Lancashire
Registered: 2007-08-27
Posts: 3,049
Website

Re: Tilapia

Yeah, but as you always say louis, energy is dirt cheap on Mars and we'll have as much as we need.

What fish can be raised on insects such as black soldier fly larvae? I'm thinking we could feed the insects on waste, then feed to the insects to fish to get more palatable protein.


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

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#9 2017-08-17 17:50:12

louis
Member
From: UK
Registered: 2008-03-24
Posts: 4,634

Re: Tilapia

Yes, it's true we will have an abundance of energy...but it would be insane to expend it on aquaculture when there are so many better uses e.g. agriculture which can produce useful materials as well as food.  There is another parameter - human labour input.  Whilst energy is not a great constraint, if there is any labour input, then it becomes a restraint in a small colony with many other tasks (e.g. life support) to attend to.

I'm hoping we never introduce insects to Mars! smile  They don't really serve any useful purpose in the context of a Mars colony...we'll be doing the recycling rather than the boll weevils. smile  They are difficult to manage.


Terraformer wrote:

Yeah, but as you always say louis, energy is dirt cheap on Mars and we'll have as much as we need.

What fish can be raised on insects such as black soldier fly larvae? I'm thinking we could feed the insects on waste, then feed to the insects to fish to get more palatable protein.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#10 2017-08-17 18:21:49

Oldfart1939
Member
Registered: 2016-11-26
Posts: 1,598

Re: Tilapia

I'm also hopeful that we don't accidentally introduce/carry along with us little things like Salmonella. This is one reason to take along externally sterilized chicken eggs, Tilapia eggs, certified disease free breeding stock of other species. This is how trichinosis has been virtually eliminated from pork raised in the USA.

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#11 2017-08-17 18:53:04

IanM
Moderator
From: Chicago
Registered: 2015-12-14
Posts: 275

Re: Tilapia

Oldfart1939 wrote:

I'm also hopeful that we don't accidentally introduce/carry along with us little things like Salmonella. This is one reason to take along externally sterilized chicken eggs, Tilapia eggs, certified disease free breeding stock of other species. This is how trichinosis has been virtually eliminated from pork raised in the USA.

Diseases are particularly harmful for fish, as treating diseases is very impractical since only one fish at a time can be treated. Therefore, usually if a fish is infected the entire school would have to be slaughtered and disposed of, bringing us back to square one. (On another note, I guess when we have chickens on Mars, we'll make egg washing mandatory like the United States, rather than forbidden as in Europe. Sure, it means we'll have to refrigerate them, but it does sterilize them pretty well.)


Louis wrote:

There is another parameter - human labour input.  Whilst energy is not a great constraint, if there is any labour input, then it becomes a restraint in a small colony with many other tasks (e.g. life support) to attend to.

I'm hoping we never introduce insects to Mars! smile  They don't really serve any useful purpose in the context of a Mars colony...we'll be doing the recycling rather than the boll weevils. smile  They are difficult to manage.

Agreed on both counts. There is a certain opportunity cost associated with agriculture, and this is higher with animals since animals also have to eat food that would otherwise be for human consumption. And even when Mars has been terraformed, there is probably no need to ever introduce mosquitoes into it. Although I might be willing to make an exception to the no-insects rule for bees and their honey.


The Earth is the cradle of the mind, but one cannot live in a cradle forever. -Paraphrased from Tsiolkovsky

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#12 2017-08-17 19:08:16

Oldfart1939
Member
Registered: 2016-11-26
Posts: 1,598

Re: Tilapia

Bees are an absolute necessity. Can't grow many crops without pollination. Can't collect fertile seeds for further propagation, otherwise.

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#13 2017-08-18 04:58:33

louis
Member
From: UK
Registered: 2008-03-24
Posts: 4,634

Re: Tilapia

I like bees but already researchers have produced tiny flying robots...no doubt in a few years these could be programmed to do the same job as bees.

https://wyss.harvard.edu/technology/aut … -robobees/

Put it this way, the introduction of life forms onto Mars has to be strictly controlled and managed. The introduction of insects is I think problematic because of their ability to reproduce at a rapid rate and produce negative results: disease, infestation of life support systems, crop reduction etc.

Maybe bees will pass muster, but that would need to be investigated and assessed thoroughly.

Oldfart1939 wrote:

Bees are an absolute necessity. Can't grow many crops without pollination. Can't collect fertile seeds for further propagation, otherwise.

Last edited by louis (2017-08-18 04:59:14)


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#14 2017-08-18 07:34:26

Oldfart1939
Member
Registered: 2016-11-26
Posts: 1,598

Re: Tilapia

Louis-

There always seems to be a high-tech solution to simple problems. We don't need the additional layer of technical complexity added where bees not only pollinate the plants, but also produce honey.

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#15 2017-08-18 08:25:58

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 5,701
Website

Re: Tilapia

Oldfart1939 wrote:

bees not only pollinate the plants, but also produce honey.

Mmm. Honey! smile

I have to agree with Oldfart1939 on this one. We have biological self-replicating and self-repairing miniature robots that can pollinate crops, collect nectar from multiple tiny flowers, concentrate that nectar so sugar concentration will prevent growth of bacteria/mould/fungus/yeast, and add specific anti-bacterial agents. These biological robots are called bees. I don't see mechanical robots working as well. Other insects can pollinate: bumblebees, pollen wasps, bee flies, hover flies, mosquitoes, ants, butterflies, moths, flower beetles, bats, humming birds, sunbirds, "honeyeater" birds, and even some lizards and small mammals. However, only honey bees produce honey.

Honey bees add an enzyme called Glucose oxidase which converts sugar to gluconic acid and hydrogen peroxide. These suppress bacterial growth; the "anti-bacterial".

The natural pollinator for cacao trees are biting midges. Those trees produce cocoa for chocolate. These midges look like mosquitoes but but much smaller. They fly so slowly that you can walk at a fast pace more quickly than they can fly. On Mars, a separate greenhouse would grow cacao trees, and since midges require rotting vegetation on the ground and other plants, those would be grown in the same greenhouse. Such a greenhouse would have a tunnel tens of metres long with air flow into the greenhouse, the breeze deliberately faster than midges can fly. That will prevent said insects from escaping, although human workers could easily just walk in or out.

Last edited by RobertDyck (2017-08-18 14:13:20)

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#16 2017-08-20 14:46:20

elderflower
Member
Registered: 2016-06-19
Posts: 1,087

Re: Tilapia

I would be inclined to avoid the biting midges. They can sit on a human whilst he walks out of the enclosure and be carried into the accommodation even if they can't fly in his wake.. This is not likely to be popular.
Honey has great anti bacterial properties, eg in wound dressings, as well as being tasty.
You wont get the same yields that earth bee keepers get as they supply a sugar supplement to their bees after taking off large amounts of honey

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#17 2017-08-20 16:51:02

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 15,597

Re: Tilapia

Unless Oldfart1939 wishes to have the continued off topic discusion of pollination, Flies, bees ect I think we should get back to fish and what it would take to keep bacteria and other issues are resolved as this is a food group that man should be getting once on mars for long term health.

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#18 2017-08-20 20:09:10

Oldfart1939
Member
Registered: 2016-11-26
Posts: 1,598

Re: Tilapia

SpaceNut-

I agree. Tilapia seems to be a possibility that would need a lot of water and a modicum of energy, but the protein produced would be invaluable. The water with high ammonia content would be wonderful adjunct for gardening irrigation.

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