Laboratory-induced development of the ice-ice disease of the farmed red algae Kappaphycus alvarezii and Eucheuma denticulatum (Solieriaceae, Gigartinales, Rhodophyta)

Abstract

The most common perception of unfavorable environmental factors causing the ice-ice disease in the farmed seaweeds, Kappaphycus and Eucheuma, was demonstrated in this study for the first time using stressful conditions of abiotic factors in a continuous culture system. Light intensity of less than 50 /mol photon m -2 s-1 and salinity of 20%o or less induced ice-ice whitening characterized by short segments at midbranches which were similar to those observed in the Philippine seaweed farms, while temperatures of up to 33-35 C resulted in wide-scale whitening leading to complete damage of the branches. These effects were preceded by slow growth rates from an optimum of 3.7% d -1 to almost -2.0% d -1. Mechanical stress by wound injury did not result to ice-ice whitening similar to the above. Environmental factors observed to trigger ice-ice in the laboratory, although may not necessarily parallel those in the field, may act synergestically to produce similar effects.

Role of secondary metabolites as defense chemicals against ice-ice disease bacteria in biofouler at carrageenophyte farms

“…Subsequent studies have examined and identified the abiotic factors that contribute to disease emergence, causative organisms and seasonality of disease outbreak (Largo et al 1995;Vairappan and Chong 2006). However, the dynamics of biofoulers on the culture lines and their possible resistance towards the "iceice" disease bacteria has not been reported to date.…”

“…(HP0205UMS), Streptococcus sp. (HP0305UMS), Citrobacter freundii (HP0405UMS), Escherichia coli (SP0505UMS) and Klebsiella pneumoniae (HP0605UMS)Bacteria from diseased seaweed were isolated and identified using modified media and techniques described by Largo et al (1995), and Vairappan and Chong (2006). Meanwhile, the human pathogenic bacteria were obtained from Department of Pathology, Queen Elizabeth Hospital, Kota Kinabalu, Sabah.…”

In vitro cultivation of three Kappaphycus alvarezii (Rhodophyta, Areschougiaceae) variants (green, red and brown) exposed to a commercial extract of the brown alga Ascophyllum nodosum (Fucaceae, Ochrophyta)

“…Vairappan et al (2008) comment that this disease was first reported in the Philippines by Trono (1974) being further related to unfavorable environmental factors in cultivation sites by Uyenco et al (1981). It was reported that Vibrio-Aeromonas and the Cytophaga-Flavobacterium complexes were responsible for inducing the "ice-ice" disease in individuals exposed to high temperature, low salinity, and irradiance (Largo et al 1995a(Largo et al , b, 1997(Largo et al , 1998.…”

Factors Influencing the Growth Rates of Three Commercial Eucheumoids at Coastal Sites in Southern Kenya

“…The cause of 'ice-ice' is not well understood but there has been a general consensus that 'ice-ice' is due to physical and chemical stresses (Uyenco et al, 1981;Largo et al, 1995;Mtolera, 1996). High 'ice-ice' occurrence was observed at Kibuyuni from November to January, coinciding with the period of high temperature and salinity.…”