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Half a century of Eucheuma/Kappaphycus farming, Half a century of maladies: Is there a missing link? - Dr. Danilo Largo


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Half a century of Eucheuma/Kappaphycus farming, Half a century of maladies: Is there a missing link? - Dr. Danilo Largo

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This topic was modified 3 years ago by Phyconomy Admin

Hello Danny
A nice presentation and thanks.
Ice ice is a Pandora's Box of multiple organisms affecting euchuematoid health.

Are Eucheuma and Kappaphycus equally susceptible -- under the same detrimental environmental conditions/stresses?

How does one go about selecting "resistant" strains from any one given strain or species?
What would be the selective pressures and how could you test for them?

Thinking about the present pandemic and "cures" you see any form of "vaccine" becoming available for the eucheumatoids to provide pest protection?

Thank you Alan

To answer your questions:

It seems K. alvarezii (and K. striatum?) is more susceptible to ice-ice than E. denticulatum under the same detrimental environmental stress based on personal observations. I think it has something to do with some inherent mechanism among eucheumatoids of producing antimicrobial compounds which could vary amongst species, like E. denticulatum being able to produce hydrogen peroxide and halogens as detected by the team of Marianne Pedersen. Also Matt Dring has a review paper entitled "Stress Resistance and Disease Resistance in Seaweeds: The Role of Reactive Oxygen Metabolism (Advances in Botanical Research, Vol,. 43, pp. 175-207 (2005) that will be a good reference.

I don't really have an answer on how we can select "resistant" strains unless we start from scratch of from using cultivars developed from spores or gametes where their genes still have the robustness against stressors.

High temperature and light intensity which are directly associated with global warming should be top on the list of selective pressures that can be used to test new strains developed from either spores or gametes. Salinity can be second in the list for the reason that most seaweed farms are coastal and shallow and are directly under the influence of freshwater sources and heavy downpour during tropical monsoon rains.

The pandemic gives us a hint on what can also happen to our seaweeds under this cloud of climate change. It seems that applying biostimulants that could promote better growth and health (affording the seaweed resistance to ice-ice and epiphytes) are working like "vaccines" for the current strains but for how long this will afford them such protection, I think, will need more studies. BFAR is now comparing the different biostims (including AMPEP and locally-produced versions) with some promising results.

I hope I have answered some of your questions?

Cheers, Alan.

Hi Dr Danny,

This is further to Dr Alan's suggestion, I would like to suggest farming of Sargassum as inter crop with Eucheumatoid cultivation as Sargassum has been reported to even repel grazers due to phlorotannins.

CRK Reddy

7 Answers

Very useful presentation Dr. Largo.

Is it the case that ice-ice syndrome occurred in the presence of light, temperature and salinity stress even though microbes were not present?

In the case of opportunistic microbial presence, to what extent are the microbes pathogens, as opposed to being active in decomposing necrotic tissue resulting from environmental stress?


Hi Iain,

Thank you for your question. As we have shown in our Aquatron experiment, stressful levels of at least, light, temperature and salinity, can lead to the development of ice-ice-like  condition (thallus whitening in short segments or the whole cultivar).

In the case of opportunistic microbial presence, even a subtle level of stress of the thalli which, as we have observed, caused their diminished ability to produce antimicrobial agent, thus  is enough to trigger an ice-ice condition. Without the stress factor, high level of antimicrobial compounds as produced in a healthy eucheumatoid could parry the potential attack by opportunistic pathogens most, if not, all have hydrolytic enzymes that facilitate the digestion of cellulosic cell walls and hydrolysis of polysaccharides (carrageenan) in the intercellular spaces. This is what causes the "ice-iced" thallus to collapse in the more advanced stage.

I hope I have answered your question. - Danny


Hallo Danny

I have an idea to cultivate seaweed from 2 different species: Kappaphycus alvarezii and K. spinosum on the same rope alternately.

I think that when both species of seaweed are stressed due to the extreme changing environment then there are chemical compounds that are released to protect them. I found that spinosum has advantages or has better endurance than alvarezii so there is a chance that spinosum's chemical compounds can help reduce stress on alvarezii. How do you think about my opinion?


Dear Dr. Aslan,

Your idea makes a lot of sense. I know E. denticulatum has this halogen compounds from the studies of Dr. Marianne Pedersen and team. These compounds have antimicrobial properties to protect the seaweed from microbial attack and by putting this species together with K. alvarezii can perhaps afford the latter some protection. Perhaps you can start in a microcosm and then try it too in the field?


Thanks for your question.



Hi Danilo. Thank you for your presentation. Just to let to know, I observed the same (but opposite) thing in Brazil. Ice-ice disease occurance in low temperatures as well, and of course, as you mentioned before, with low salinity. The most interesting thing is that sometimes the ice-ice starts up to one month after the stress condition. Have you observed something like that too or you observed ice-ice after a few days?

Hi Leila,

I used K. alvarezii in my experiment in Tosa Bay (Kochi, Japan) some years ago. There this tropical seaweed cannot tolerate temperatures below its normal range of 23-30oC like here in the Philippines. Temperature could fall below this range in autumn in the subtemperate latitude and the seaweed could manifest the ice-ice condition soon enough (a week or so), not a month long as you have sometimes observed in Brazil. Would it be that the decline in temperature in (Sao Paolo?) Brazil not that abrupt like those in Kochi? I think that suboptimal level of certain factors like temp, salinity, and light intensity may not immediately lead to ice-ice condition, but drastic change could immediately manifest the disease.

Best regards,

Hallo Danny,

Indonesia has also entered the age of 50 years in the development of seaweed cultivation. Until these days, there are still many problems faced here in Indonesia ranging from aspects of cultivation, spatial planning, marketing to post-harvest. Based on the above-mentioned problems, is there any suggestion from you that the above issues can be resolved

We actually share the same problems here in the Philippines and there is no easy solution to all these complex problems. But I think, we can approach these problems according to different stages, from: 1) pre-farming stage (i.e. access to good-quality seedlings of the right species, access by farmers to credit facilities), 2) farming stage (knowledge on seaweed health management, farming systems, impact of warming seas/global warming, pollution, peace & order), 3) post-harvest (including seaweed quality based on moisture content, carrageenan yield, gel strength, presence of contaminants, e.g. heavy metals), 4) marketing (farmgate price not reflecting the actual market price with middlemen/traders earning more than farmers), 5) processing (strong lobby by interest groups against carrageenan in the world market).


Hi Dr. Largo,

Thanks for that wonderful presentation highlighting the bio-chemical warfare taking place between seaweeds and the microbes they host.

I have personally seen these effects on plants especially in terms of silt deposits. When grown in tube nets, the best growing seaweeds will correspondingly have the cleanest tube nets/lines - even in waters with high turbidity. I believe what we call silt deposition is not just silt, but a combination of silt and biofilms forming aggregate complexes which stick to both farming materials and plants. The good growing plants probably secrete some of the antimicrobials you describe in your presentation, preventing biofilm formation in nearby surfaces.

From a physico-chemical point of view, the concentration of these antimicrobials would be highest next to the plant thallus and dilute out as we move away from the plant. This would mean that the effect of an antimicrobial would be much lesser 300 mm away from the plant as compared to 3mm from the thallus. Have you ever considered growing seaweed very close to each other - so that the effective concentration of these antimicrobials from the neighbouring plants add up and increase? These kind of synergistic effects are probably what drives the formation of lush, dense seaweed beds.

Regards, Nelson


Thank you for sharing your knowledge, Dr. Largo. I really enjoyed your presentation.

I would just like some clarifications on two things:

1. What is the optimal level of salinity, temperature, and light salinity for seaweeds (Kappaphycus and Eucheuma)?

2. You mentioned that farming seaweeds in shallow areas is no longer economically viable, however, this is still practiced in some localities, especially by women. If the only space available for seaweed farming is in the shallow area(s), what can you suggest to the farmers so that they will still be able to maximize the economic benefits from seaweed farming (i.e., reduce the incidence of ice-ice disease)?


Thanks, Danny, for your response to my post about stress and opportunism. I think I am beginning to understand more, and once again the answer seems to be "all of the above". Environmental stress and biological responses interacting in those endless cycles of adaptation.


Cheers, Iain