Seaweed Kappaphycus Alvarezii Research Articles

Correlation of Water Quality Parameters on Growth Performance of Seaweed (Kappaphycus alvarezii Doty, 1986) Cultivated with Diagonal Method

Kappaphycus alvarezii seaweed is an exported commodity that has economic value and is a leading commodity in aquaculture. The present study aims to analyze the correlation between water quality parameters and the growth of Kappaphycus alvarezii seaweed using the diagonal method. A completely randomized design using three treatments and four replications was applied for the experimental design. The research was carried out from May to June 2023 in the waters of Angkue Village, Bone Regency, Indonesia. Treatment in this diagonal model was based on the length of the diagonal rope, namely 2.5 m (treatment 1), 3.5 m (treatment 2), and 4.5 m (treatment 3) of the water depth and seaweed maintained for 42 days at a water depth of five meters. The results showed that the absolute growth of seaweed was 17,537.0 g during the study, with an average of 5845.67 ± 359.34 g. In treatment 1, the absolute growth was 1368.55 ± 5.29 g; in treatment 2, it was 1467.83 ± 4.58 g; and in treatment 3, it was 1547.88 ± 1.24 g, with the highest growth rate and the lowest growth rate in the first week. Water quality parameters all contribute positively to seaweed growth, but those that contribute most strongly to seaweed growth are brightness, phosphate, nitrate, and salinity.

A red seaweed Kappaphycus alvarezii-based biostimulant (AgroGain®) improves the growth of Zea mays and impacts agricultural sustainability by beneficially priming rhizosphere soil microbial community.

The overuse of chemical-based agricultural inputs has led to the degradation of soil with associated adverse effects on soil attributes and microbial population. This scenario leads to poor soil health and is reportedly on the rise globally. Additionally, chemical fertilizers pose serious risks to the ecosystem and human health. In this study, foliar sprays of biostimulant (AgroGain/LBS6) prepared from the cultivated, tropical red seaweed Kappaphycus alvarezii increased the phenotypic growth of Zea mays in terms of greater leaf area, total plant height, and shoot fresh and dry weights. In addition, LBS6 improved the accumulation of chlorophyll a and b, total carotenoids, total soluble sugars, amino acids, flavonoids, and phenolics in the treated plants. LBS6 applications also improved the total bacterial and fungal count in rhizospheric soil. The V3-V4 region of 16S rRNA gene from the soil metagenome was analyzed to study the abundance of bacterial communities which were increased in the rhizosphere of LBS6-treated plants. Treatments were found to enrich beneficial soil bacteria, i.e., Proteobacteria, especially the classes Alphaproteobacteria, Cyanobacteria, Firmicutes, Actinobacteriota, Verrucomicrobiota, Chloroflexi, and Acidobacteriota and several other phyla related to plant growth promotion. A metagenomic study of those soil samples from LBS6-sprayed plants was correlated with functional potential of soil microbiota. Enrichment of metabolisms such as nitrogen, sulfur, phosphorous, plant defense, amino acid, co-factors, and vitamins was observed in soils grown with LBS6-sprayed plants. These results were further confirmed by a significant increase in the activity of soil enzymes such as urease, acid phosphatase, FDAse, dehydrogenase, catalase, and biological index of fertility in the rhizosphere of LBS6-treated corn plant. These findings conclude that the foliar application of LBS6 on Z. mays improves and recruits beneficial microbes and alters soil ecology in a sustainable manner.

PENGARUH KONSENTRASI KOH PADA PROSES EKSTRAKSI RUMPUT LAUT (Kappaphycus alvarezii) TERHADAP SIFAT ALKALI TREATED COTONII (ATC)

One of the superior fishery commodities abundant in Indonesian waters is Kappaphycus alvarezii seaweed. The seaweed type K. alvarezii can be used to make Alkali Treated Cottonii (ATC), a raw material for carrageenan. Making ATC goes through seaweed extraction stages, which can be done using conventional methods. Data collection for this research was carried out using observation, interviews, and active participation. The results of ATC processing using conventional methods and variations of KOH show that the administration of KOH affects the quality of the ATC product; the higher the ATC, the higher the yield percentage and temperature produced by the extract solution. The best use of KOH is in the treatment with a KOH concentration of 8%, a water content of 13.73%, a yield of 73.62%, and a temperature of 58.15%.

Assessment of regulatory compounds in commercial red seaweed Kappaphycus alvarezii after long-distance transportation

Assessment of regulatory compounds in commercial red seaweed Kappaphycus alvarezii after long-distance transportation

Current status of environmental water quality of Kappaphycus alvarezii seaweed cultivation in the Seribu Islands, Indonesia and the concept of sustainable development by using a System Dynamic Model approach

The aim of this research is to analyze the current status of water quality in seaweed cultivation environments related to the decline in seaweed production. Field research was conducted in the Seribu Islands Regency, DKI Jakarta, during April and May 2023. The analysis of environmental factors encompassed physical, chemical, and biological parameters at 12 designated sampling points. The results of the analysis of water quality parameters generally meet the requirements, except for oil and grease at 7-51 mg/L and nitrate at 1.60-6.3 mg/L, both of which exceed the quality standards for biota. Plankton analysis shows the total abundance of plankton reaches 36 to 9,070 ind/L. Evaluation of the suitability class shows that the waters are in class S (Suitable). The Pollution Index value ranges from 6.51 to 8.05, indicating a fairly polluted status. The high levels of oil and grease, nitrate, and the presence of index pollutants have a significant influence on the decline in seaweed production in the Seribu Islands Regency. The preparation of improvement strategies can be conducted using a System Dynamics Model approach, involving the creation of comprehensive Causal Loop Diagrams. This process considers four key factors: environmental water quality, human resources, technology, and seaweed.

Cultivation of Seaweed Kappaphycus alvarezii with Various Substrates Different on Laboratory Scale

Kappaphycus alvarezii is an important red algae and can be used as one of the primary raw materials in fisheries. It is widely cultivated because of its relatively cheap production technology, and post-harvest handling is simple and easy. This algae has excellent economic value for carrageenan producers. Carrageenan is used as a food ingredient, cosmetics, and medicine. The success of cultivating K. alvarezii seaweed can be achieved if a suitable environment for its growth supports it. One of the environmental aspects that influence the growth of K. alvarezii seaweed is the bottom substrate of the waters. This research aims to analyze the best substrate for cultivating green K.alvarezii seaweed on a laboratory scale. This research used an experimental method with a Completely Randomized Design (CRD) consisting of 4 treatments and three repetitions, resulting in 12 experimental units. The treatments tested were different substrates: a coral substrate, a sand substrate, a volcanic rock substrate, and a coral sand substrate. The results of this study showed that the average survival rate in various substrate treatments ranged from 7.16% to 39%, final weight ranged from 1.43 g to 7.8 g, specific loss rate ranged from -3.157%/day to -5.124%/day, carrageenan yield ranged from 6.8% to 18.4%, and thallus tissue showed that all treatments still showed the presence of cortex and medullary tissue with varying shapes and structures

Identification of Kappaphycus alvarezii seaweed based on phylogenetic and carrageenan conten

Increasing seaweed production requires accurate information regarding the genetic sources of seeds used. Identifying the seaweed species Kappaphycus molecular is one of the solutions to ensure seaweed cultivators choose seeds for their cultivation businesses. Molecular identification is essential for the system traceability of seaweed products and the creation of databases regarding species variant information Kappaphycus alvarezii cultivation as potential data collection for developing and genetically breeding seaweed seeds. To date, there is no information on the genetic potential of K. alvarezii cultivated in various seaweed cultivation centers in Indonesia. This study aimed to obtain phylogenetic details based on identification of the genetic source using DNA molecular markers barcoding rbcL and analysis of carrageenan content using the Fourier transform infra-red (FTIR) spectrum. The results of DNA sequencing analysis and FTIR testing of 16 varieties of seaweed seedlings obtained from various cultivation centers in Indonesia showed 99% similarity with K. alvarezii, a producer of kappa carrageenan.
 
 Keywords: DNA sequencing, phylogenetics, haplotypes, kappa-carrageenan, rbcL
 
 
 ABSTRAK
 
 Peningkatan produksi rumput laut memerlukan informasi yang akurat mengenai kepastian sumber genetik bibit yang digunakan. Identifikasi spesies rumput laut Kappaphycus secara molekuler merupakan salah satu solusi untuk memberikan kepastian pada pembudidaya rumput laut untuk memilih bibit bagi usaha budidaya. Identifikasi molekuler sangat penting dalam sistem traceability produk rumput laut dan pembuatan basis data mengenai informasi varian spesies Kappaphycus alvarezii budidaya sebagai pendataan potensi untuk pengembangan dan pemuliaan bibit rumput laut secara genetis. Sampai saat ini belum tersedia informasi mengenai potensi genetik rumput laut K. alvarezii yang dibudidayakan di berbagai sentra budidaya rumput laut di Indonesia. Penelitian ini bertujuan untuk memperoleh informasi filogenetik berdasarkan identifikasi sumber genetiknya menggunakan penanda molekuler DNA barcoding rbcL serta analisis kandungan karaginannya menggunakan spektrum Fourier Transform Infra-Red (FTIR). Dari hasil analisis sekuensing DNA dan pengujian FTIR terhadap 16 varietas bibit rumput laut yang diperoleh di berbagai sentra budidaya di Indonesia menghasilkan 99% kemiripan yang tinggi dengan K. alvarezii penghasil kappa karagenan.
 
 Kata kunci: DNA sekuensing, filogenetik, haplotipe, kappa-karagenan, rbcL

RESTORASI EKOSISTEM PADANG LAMUN MELALUI TEKNOLOGI BIO-FADs TREE DENGAN BAHAN DASAR RUMPUT LAUT PADA PERIKANAN DEMERSAL

Coastal water ecosystems in general have experienced damage as a result of fishing that is not environmentally friendly. This unfriendly fishing causes the fish's feeding grounds to be damaged so that fishing activities in coastal areas need to involve fishing aids to collect fish. The fishing aids implemented are in accordance with the fishing objectives to be achieved. The implementation of fishing aids aims to attract attention and bring fish to the area where the attractor is installed, making it easier to catch. One of the fishing aids used is Biological Fish Aggregating Devices (Bio-FADs Tree) or live FADs equipped with Kappaphycus alvarezii seaweed which acts as an attractor to attract fish so they can be easily caught. This service is carried out in Mamuju waters for the purpose of catching demersal fish. The service is carried out using trap fishing equipment. The results of the service showed that the catches obtained were Pink ear emperor (Lethrinus lentjan), Redbelly yellowtail fusilier (Caesio cuning), Streaked spinefoot (Siganus javus), batik Vermiculated spinefoot (Siganus vermiculatus) and Orange-spotted spinefoot (Siganus gutattus), White-spotted spinefoot (Siganus canaliculatus), and Surf parrotfish (Scarus rivulatus). All of the catches are fish of important economic value

A biostimulant prepared from red seaweed Kappaphycus alvarezii induces flowering and improves the growth of Pisum sativum grown under optimum and nitrogen-limited conditions.

Nitrogen (N) is one of the critical elements required by plants and is therefore one of the important limiting factors for growth and yield. To increase agricultural productivity, farmers are using excessive N fertilizers to the soil, which poses a threat to the ecosystem, as most of the applied nitrogen fertilizer is not taken up by crops, and runoff to aquatic bodies and the environment causes eutrophication, pollution, and greenhouse gas emissions. In this study, we used LBS6, a Kappaphycus alvarezii-based biostimulant as a sustainable alternative to improve the growth of plants under different NO3 - fertigation. A root drench treatment of 1 ml/L LBS6 significantly improved the growth of Pisum sativum plants grown under optimum and deficient N conditions. No significant difference was observed in the growth of LBS6-treated plants grown with excessive N. The application of LBS6 induced flowering under optimum and deficient N conditions. The total nitrogen, nitrate and ammonia contents of tissues were found to be higher in treated plants grown under N deficient conditions. The LBS6 treatments had significantly higher chlorophyll content in those plants grown under N-deficient conditions. The root drench application of LBS6 also regulated photosynthetic efficiency by modulating electron and proton transport-related processes of leaves in the light-adapted state. The rate of linear electron flux, proton conductivity and steady-state proton flux across the thylakoid membrane were found to be higher in LBS6-treated plants. Additionally, LBS6 also reduced nitrogen starvation-induced, reactive oxygen species accumulation by reduction in lipid peroxidation in treated plants. Gene expression analysis showed differential regulation of expression of those genes involved in N uptake, transport, assimilation, and remobilization in LBS6-treated plants. Taken together, LBS6 improved growth of those treated plants under optimum and nitrogen-limited condition by positively modulating their biochemical, molecular, and physiological processes.

Analysis of Carbon Sequestration Rate in Seaweed (Kappaphycus alvarezii) Based on Environmental Mitigation

Blue economy is a development concept that develops by relying on marine or aquatic resources. An increase in carbon dioxide (CO2) in the atmosphere is fueling climate change. This study aims to analyze the rate of carbon uptake in the waters, using seaweed Kappaphycus alvarezii which utilizes carbon to be converted into biomass before returning to the air. The results showed that highest carbon absorption rate was found in location A with the highest total carbon absorption of 94.87±0.77 tons C/planting cycle, then treatment B with 83.96±0.54 tons C/planting cycle, and the lowest in treatment C with 76.88±0.18 tons C/planting cycle. Water quality parameters are still mostly in decent condition for the cultivation of Kappaphycus alvarezii seaweed. Salinity conditions of waters are relatively high (35-39 ppt) even though the optimum seaweed grows in the range of 30-34 ppt. The conclusion of the study is that the highest total carbon is found at Location A, which is 94.87±0.77 tons C/planting cycle. The suggestion of this study is that it is necessary to analyze the suitability of seaweed cultivation land with various water quality parameters, so that mapping of potential types of seaweed that can be cultivated according to the characteristics and quality of the waters.

Selection and cultivation of seaweed Kappaphycus alvarezii using a long line system (outdoor)

In outdoor cultivation at Amal Beach, three seeding mass selections were reared for 30 days for each cycle. Each variety had a different DGR %/day (Daily Growth Rate %/day) value at the end of the growing season on G1-G2-G3 ranging from 3.62-5.90 %/day, which were still categorized as good, and G3 var.Lampung had the highest DGR value. Carrageenan yield values in this study, G1 to G3, ranged from 23.16% to 45.87%, where the G3 G2 G1 treatment. The best thallus samples (20% were selected for each generation) resulted in carrageenan yield sample population in each variety, where var.Lampung var.Tarakan var.Kupang. The biplot analysis shows that the DGR variable vector coincides with the IAA, Phosphate, Gibberellin, and Ammonia vectors. Ammonia stepwise regression analysis (sigα) affects DGR with an Ammonia coefficient value of 4.89; meaning that for each increase in the Ammonia value by one unit, the estimated mean value of DGR will increase by 4.89. Thus, the application of the mass based on the results of this study was able to increase the DGR value Kappaphycus alvarezii, which in turn produce the highest yield of carrageenan with K. alvarezii var.Lampung G3 was the best seed candidate to be developed at the seaweed cultivation site in Tarakan City.Keywords:AlgaePhytohormonesCarrageenanNitrogenViscosity

Interaction of nutrient enrichment and farming method on performance of the red seaweed Kappaphycus alvarezii

To meet the increasing demand for kappa carrageenan, several strategies have been employed to improve eucheumatoid seaweed productivity, such as nutrient enrichment (NE) and the application of some efficient farming methods (FM). This study aims to investigate the interaction of NE (applied as ammonium phosphate at 3.5 g L−1) and farming method on the performance of the eucheumatoid seaweed Kappaphycus alvarezii. Three farming methods, that is, Sway (SW), Spring (SP), and modified fixed-off bottom (MFOB), were employed for nutrient-enriched (NE) and non-enriched control fronds for a period of 45 days. NE significantly improved the growth and carrageenan yield of the seaweed and afforded protection against the incidence of ice-ice disease; meanwhile, the effect of FM and NE-FM interaction was non-significant. NE increased the gel strength of the extracted carrageenan; meanwhile, SP farm led to the highest gel strength, followed by MFOB.

Underpinning beneficial maize response to application of minimally processed homogenates of red and brown seaweeds.

Sap from the fresh seaweed Kappaphycus alvarezii (KA) has been reported to improve crop growth, quality, and stress alleviation. However, limited studies are reported for the minimally processed aqueous homogenates (MPHs) derived from dry seaweeds. The present investigation was envisaged to characterize the MPHs from the red seaweed KA and a brown seaweed Sargassum wightii (SW) and also assess the effect of foliar application on maize (Zea mays) crop performance when applied alone or in proportions ranging from 0% to 100%. Two doses (0.35% and 0.7%) were compared with control. Both the MPHs contained several compounds like retronecine, tyrosyl-glycine, hexyl 2-furoate, 1-phosphatidyl-1D-myo-inositol, 12-(2,3-dihydroxycyclopentyl)-2-dodecanone, and trihomomethionine and many others that have known bioactivity for enhancing plant growth and providing stress tolerance. Both doses of MPHs enhanced crop growth and yield; however, the best response was in general observed at a lower dose. The MPH of SW at 100% gave the highest seed yield at a lower dose, which was also on par with that obtained under a lower dose of 100% KA. Other combinations, 80:20 and 40:60 KA : SW, were also found to give comparable yields. The highest dose of 100% MPH of SW was found on par with control, a phenomenon that was investigated in detail with respect to metabolites and antioxidant profile in leaves as well as membrane modeling. Higher ROS and certain sugar and organic acids were observed in 100% MPH of SW at a higher dose, although none of the antioxidant enzymes were significantly affected, nor was there any change in membrane characteristics of the leaf with respect to control as well as lower dose. Improvements in the seed yield were attributed to improved photosynthate production on account of higher dry matter accumulation in the MPH-treated plants, which may also be attributed to the presence of bioactive compounds in the biostimulants. In the future, it is imperative to direct scientific investigations towards the quantification and identification of the most effective concentrations of these compounds within MPHs to optimize plant responses. The study indicated the beneficial use of the MPHs towards increasing crop production by employing optimum dose as foliar spray to crops.

Nucleotide Composition of the rbcL Gene Sequence on Cultivated Kappaphycus alvarezii in East Java – Indonesia

Kappaphycus alvarezii seaweed is an important fishery commodity in Indonesia because it contains carrageenan, an important main ingredient in various industries. Research on the genetic characterization of seaweed in Indonesia is important as a source of information and genetic data needed to develop aquaculture practices such as breeding programs. Therefore, this study was conducted to determine the nucleotide composition of the rbcL gene sequence in Kappaphycus alvarezii as part of a genetic characterization study of Kappaphycus alvarezii seaweed in East Java. This study used five samples taken in Banyuwangi, Situbondo and Sumenep and compared them with the Kappaphycus alvarezii seaweed database at GenBank. The method used was the PCR method, and the primer pairs used were F-577 5'-GTATATGAAGGTCTAAAAGGTGG-3' and R-753 5'-GCTCTTTCATACATATCTTCC-3'. Based on research, primers F-577 and R-753 succeeded in amplifying the rbcL gene in Kappaphycus alvarezii samples in a partial manner with a length of 295 – 299 bp. The DNA sequence results of the sample have a similarity of 100% to the database in GeneBank. Nucleotide composition analysis shows the existence of genetic variations in the DNA sequences studied.

BIOMASS PRODUCTION, GROWTH RATE, AND CARRAGEENAN CONTENT OF Kappaphycus alvarezii PERFORMED BY VERTICULTURE METHOD WITH DIFFERENT INITIAL WEIGHT

Kappaphycus alvarezii seaweed is important for the processing industry because it contains carrageenan used as a stabilizer, thickener, material forming an emulsifier. This study aimed to find the best and optimal initial seed weight treatment for maximum biomass production, growth rate, and carrageenan content. The research location was in the waters of Aeng Batu-Batu Village, Takalar Regency, South Sulawesi in August-September 2022. The randomized block design method (RAK) consisted of 4 treatments each with 4 repetitions. Seaweed seedlings from spores were weight of 20 g, 40 g, 60 g, and 80 g planted at 60 cm depth respectively and maintained for 45 days. Data analysis used (ANOVA) and W-Tuckey to determine the differences between treatments. The result of the analysis of variences showed that the weight of 40 g, 60 g, and 80 g had an effect on the biomass production, growth rate, and K. alvarezii carrageenan content. However, the highest yield was obtained at a weight of 20 g which had a very significant effect (p<0.01).

Growth of seaweed Kappaphycus alvarezii co-cultivated with Sargassum plagiophyllum using the long line method

The use of smaller seed weights < 20g has never been done for cultivating S. plagiophyllum. The study of cultivation of both species S. plagiophyllum (SP) and K. alvarezii (KA) simultaneously had never been done previously. This research was conducted in Bungin Permai coastal waters, South Konawe regency. This research aim was to examine the most suitable wet initial weight for better growth (10,15, 20g) on the growth of both species’ seaweed. The collecting data were analyzed by factorial completely randomized design with three replications. Yields were observed every 9,18,27,36,45 days of the growth period. The results showed that S. plagiophyllum had significantly higher different DGR than those of K. alvarezii (P<0.05) during cultivation period. No interaction between species and wet initial weight was found (P>0.05). In addition, the species of seeds influence the DGR. Seed of SP had higher DGR than KA, but the initial wet weight of the seeds only influences at the initial cultivation period (9th day). Broken thallus was found in the 10,15,20g seeds. The percentage of thallus damage in SP tends to be higher than KA. DGR at 10g seed weight of both species was significantly higher than other seed weights (15g and 20g; P<0.05).

A study of water depth on the growth and productivity of seaweed &lt;i&gt;Kappaphycus alvarezii&lt;/i&gt;

This study aims to investigate the impact of varying the depth of water on the growth and productivity of seaweed Kappaphycus alvarezii. The study was carried out in the seas of Pallette. The research methodology used in this study incorporates three different planting depth treatments, specifically 1.5 meters, 3 meters, and 4 meters. In each treatment, 50 grams of Kappaphycus alvarezii seeds per bunch were used. The findings of this study indicate that seaweed cultivation at a depth of 1.5 m yields significantly favourable outcomes compared to the treatments conducted at depths of 3 m and 4 m, where growth is comparatively less optimal. This occurrence can be attributed to the diminished level of light penetration at such a depth. There is an inverse relationship between the depth of seaweed planting and the rate of weight gain. The optimal depth for seaweed cultivation for 42 days is 1.5 meters, with an average specific growth rate of 3% daily. On the contrary, the treatment carried out at a depth of 1.5 m showed the most substantial increase in biomass, averaging 122 g. Additionally, the maximum yield of seaweed was observed in the same treatment, precisely measuring 1,208 g/m2.

Niche comparison and range shifts for two Kappaphycus species in the Indo-Pacific Ocean under climate change

Nowadays, eucheumatoids lead the rankings in globally cultivated seaweed production, including the seaweeds Kappaphycus alvarezii and Kappaphycus striatus. Eucheumatoids have declined in biomass over recent years, and climate change is regarded as one of the important factors. Thus, it is urgent to investigate the range dynamics of Kappaphycus under climate change. Considering its high practical relevance for conserving biodiversity, the niche conservatism hypothesis was tested between the two species through ecological niche modeling (ENM), ordination, and hypervolume approach which quantify the extent of niche overlap. In this study, we sifted the best-performing algorithm - Maxent and tuned parameters for fitting the distribution of both Kappaphycus species, compared their geographical distribution patterns, and predicted their range dynamics under climate change. All three methodological approaches indicated significant niche differences in both geographical and environmental space between the two Kappaphycus species. Our models predicted that range shifts mainly induced by rising sea surface temperature are likely to differ between two Kappaphycus species, with K. striatus suffering much range contraction (359,448 km2 in 2100s RCP8.5). By the year 2100, both Kappaphycus species are forecast to lose suitable habitats along most of the coastline of Southeast Asia under the RCP8.5 scenario. K. alvarezii is predicted to expand its distributions (96,429 km2) under the RCP2.6 scenario by the year 2100, suggesting resilience to mild global warming. Our study enhances the understanding of Kappaphycus aquaculture, and is conducive to the sustainable development of tropical seaweed by stressing the importance of conservation and investigation under climate change.

Growth and quality performances of seaweed (Kappaphycus alvarezii) with different combinations of temperature and light parameters

This study aimed to analyze the optimal combination of temperature and light for the growth and quality of Kappaphycus alvarezii seaweed. This study used a factorial completely randomized design (CRD factorial) consisting of 2 factors (temperature and light) with three replications, which included a combination of temperature 28, 31, and 34 °C with light 50 and 100 photons (µmol m−2 s−1). The test object used was a seaweed seed weighing 50 g. The results showed that the S28C100 treatment gave the highest absolute weight growth value (P<0.05). The highest specific growth rate (SGR) was found in the S28C100 and S31C100 treatments, not significantly different between the two, respectively 3.77±0.058% and 3.03±0.12%. Treatment S31C50 followed by S31C100 gave the highest value for the carrageenan yield, but there was no significant difference between the two, respectively 15.505±0.71% and 13.965±0.26%. The combination of temperature and light in this study resulted in gel strength values of 922.150±234.26 to 1048.555±266.46 g.cm−2 but not significantly different between each treatment.

THE RELATIONSHIP BETWEEN ECTOPARASITES AND THE GROWTH OF SEAWEED (KAPPAPHYCUS ALVAREZII) CULTIVATED IN THE WATERS OF MANDALLE VILLAGE, PANGKAJENE ISLANDS REGENCY

This study aims to determine the types of ectoparasites found in the thallus of cultivated seaweed Kappaphycus alvarezii and their effect on their growth. The research will be conducted in the seaweed cultivation area of Mandalle Village, Pangkajene Islands Regency. The determination of research stations was carried out purposively (purposive sampling) for three representative aquaculture stations. This is so that it can represent or describe the condition of the waters of Mandalle Village. The cultivation method used in this study was the long line method as used by residents around the study site. Maintenance construction as a sampling unit at each station point, in the form of a 25-meter long rope span of 10 ropes with a distance between the ropes of 1 m. Each stretch rope contains 100-120 seedling clumps with a distance of 20 cm between the straps. Seaweed seeds with an initial weight of 50-70 grams, tied to clump ropes. Planting of seeds is carried out at a depth of 30 cm from the surface of the water. The cultivation construction distance is installed as far as 700-1000 m from the beach. Observation of growth is done by measuring the weight of each clump or the overall weight of each clump of each span rope, at the end of each maintenance cycle. The data obtained for 45 days is then calculated using the growth formula. Seaweed samples for observation of ectoparasites were taken at 3 (three) points of the cultivation area for each bundle of seaweed. The entire surface of the sample thallus was observed with the naked eye and the loop. The results of this study indicated that all observation stations on the South, North and West coasts were dominated by barnacle ectoparasites, followed by green mussels and worms with a total percentage of 90%. While the absolute growth between all stations is relatively the same.