Seasonal aspects of growth. reproduction and spore output in G. pusillum growing (Sept. I 976-Feb. 1979) at Visakhapatnam coast were described. Plants occurred throughout the year with maximum growth in Sept. and Oct. and minimum between Jan. and April. Tetrasporophytes were predominant over the cystocarpic plants and seasonality was not observed in the abundance of these fruiting plants. Under laboratory conditions tetraspore and carpospore shedding was maximum on the 1st d and spore output gradually decreased from 2nd d onwards. Seasonal variations were not observed in the formation of sori and discharge of spores.
Digital library
-
-
Two new guaiane sesquiterpene derivatives, guai-2-en-10ά-ol(1) and guai-2-en-10ά-methanol(2) were chromatographically purified as major constituents of the CHCl3/CH3OH
-
We examined the gut health potential of the brown seaweed Ecklonia radiata and its polysaccharides. Rats consumed an AIN-93G-based diet without addition (control) or containing 5% (w/w) of ground dried whole seaweed (WS) or dried powdered polysaccharide fraction (PF) of the seaweed for 1 wk. The PF consisted largely of fucoidan and alginate. PF treatment increased cecal digesta weight relative to the control (1.36 ± 0.17 vs 0.60 ± 0.06 g/100 g body weight). Beneficial cecal total short chain fatty acids increased in response to WS (213.25 ± 14.40 μmol) and PF (208.59 ± 23.32 μmol) compared with the control (159.96 ± 13.10 μmol). Toxic protein fermentation product levels were decreased by WS and PF. Cecal numbers of bacteria relevant to gut health were determined using quantitative real-time PCR. Relative to the control, numbers of butyrate-producing Faecalibacterium prausnitzii were increased by PF supplementation, whereas WS decreased numbers of potentially pathogenic Enterococcus. In conclusion, E. radiata-derived polysaccharides have promise as prebiotic supplements.
-
Habitat selection can determine the distribution and performance of individuals if the precision with which sites are chosen corresponds with exposure to risks or resources. Contrastingly, facilitation can allow persistence of individuals arriving by chance and potentially maladapted to local abiotic conditions. For marine organisms, selection of a permanent attachment site at the end of their larval stage or the presence of a facilitator can be a critical determinant of recruitment success. In coral reef ecosystems, it is well known that settling planula larvae of reef-building corals use coarse environmental cues (i.e., light) for habitat selection. Although laboratory studies suggest that larvae can also use precise biotic cues produced by crustose coralline algae (CCA) to select attachment sites, the ecological consequences of biotic cues for corals are poorly understood in situ. In a field experiment exploring the relative importance of biotic cues and variability in habitat quality to recruitment of hard corals, pocilloporid and acroporid corals recruited more frequently to one species of CCA, Titanoderma prototypum, and significantly less so to other species of CCA; these results are consistent with laboratory assays from other studies. The provision of the biotic cue accurately predicted coral recruitment rates across habitats of varying quality. At the scale of CCA, corals attached to the "preferred" CCA experienced increased survivorship while recruits attached elsewhere had lower colony growth and survivorship. For reef-building corals, the behavioral selection of habitat using chemical cues both reduces the risk of incidental mortality and indicates the presence of a facilitator.
-
Aquaculture can have negative environmental impacts, adding to the suite of anthropogenic stressors that challenge coastal ecosystems. However, a growing body of scientific evidence indicates that the commercial cultivation of bivalve shellfish and seaweed can deliver valuable ecosystem goods and services, including provision of new habitats for fish and mobile invertebrate species. We completed a systematic literature review of studies focused on understanding habitat-related interactions associated with bivalve and seaweed aquaculture, and a brief meta-analysis of 65 studies to evaluate fish and mobile macroinvertebrate populations at farms and reference sites. Bivalve and seaweed aquaculture were associated with higher abundance (n = 59, range: 0.05× to 473×, median lnRR = 0.67) and species richness (n = 29, range: 0.68× to 4.3×, median lnRR = 0.13) of wild, mobile macrofauna. Suspended or elevated mussel and oyster culture yielded the largest increases in wild macrofaunal abundance and species richness. We describe the major mechanisms and pathways by which bivalve and seaweed aquaculture may positively influence the structure and function of faunal communities—including provision of structured habitat, provision of food resources and enhanced reproduction and recruitment—and identify the role of the species cultivated and cultivation gear in affecting habitat value. Given the continued deterioration of coastal habitats and increasing investments into their restoration, understanding how industry activities such as aquaculture can be designed to deliver food within ecological limits and have positive influences on ecosystem goods and services is essential in ensuring ecological, social and economic objectives can be achieved.
-
We determined the feasibility of using salt-tolerant plants Žhalophytes. as biofilters to remove nutrients from saline aquaculture wastewater. Suaeda esteroa, Salicornia bigeloÕii and Atriplex barclayana ŽChenopodiaceae., species with potential as forage and oil seed crops, were grown in sand in draining containers Žlysimeters. in a greenhouse experiment. They were irrigated to meet evapotranspiration demand and to produce a 0.3 leaching fraction, using aquaculture effluent generated from an intensive tilapia culture system. The effluent salinity was increased with NaCl to make salinity treatments of 0.5, 10 and 35 ppt. The plant–soil system removed 98% and 94% of the applied total and inorganic nitrogen, respectively. It removed 99% and 97% of the applied total and soluble reactive phosphorus, respectively. High removal rates occurred despite the high leaching fraction. Salt inhibited Ž P - 0.05. the growth rate, nutrient removal, and volume of water that all three plant species could process. Suaeda and Salicornia, which are succulent salt marsh species, performed better than the desert saltbush, Atriplex, at the higher salinities.
-
In recent times, marine macroalgae (commonly known as seaweeds) drawing considerable attention globally as a renewable feed stock for various industrial applications. Commercial harvesting of seaweeds has reached new milestone with 27 million tones year-1 production (95% accounts to farming) with a market value of over US$ 4.8 billion (FAO, 2016). CSIR-Central Salt and Marine Chemicals Research Institute has been actively pursuing the seaweed research for nearly half a century. This institute takes pride in being first for pioneering seaweed cultivation, heralding an era of commercial seaweed farming in India. The production of Kappaphycus alvarezii has been substantially increased from 21 dry tonnes in 2001 to 1490 dry tonnes in 2013 with concomitant purchase value of < ₹ 4.5 to 35 ₹ kg−1 (dry). However, Indian seaweed industry is still depending on natural harvest for agrophytes specifically species of Gracilaria, Gelidium and Gelidiella. The continuous harvesting of natural stocks has been a growing concern for the long-term sustainability of the resource. In order to mitigate the over exploitation pressure on natural stocks, CSIR-CSMCRI developed sustainable cultivation methods of some of these species. Recently, Gracilaria dura from Indian waters has been reported to yield quality agarose as high as 20-25% on dry wt. basis with a gelling temperature 350C and gel strength of 1% gel > 1900 g. cm-2 this has attracted industrial attention. The fast expanding biotechnology and pharmaceutical sector in India is registering steady demand for agar, underpinning the need to initiate large scale farming of this alga. Thus successful aquaculture practise has been developed for ascertaining a continuous and reliable supply of quality raw material giving impetus to commercial operations especially in Gujarat coast – of which this alga is native. Among the hydrocolloids, agar is the second most prized product after agarose. According to a recent report, the wholesale price of agar has sharply increased to an all time high of USD 35-45 per kg due to scarcity of raw materials in response to resent regulations imposed by Moroccan government on natural harvest. The ongoing global supply chain crisis of agarophytes can be capitalized by India by spear heading the farming activity. This provides a scope and immense opportunity for India to emerge as a global producer as well as exporter of agarophytes. CSIR-CSMCRI in association with National Fisheries Development Board (NFDB), Hyderabad is trying to promote young fishermen as an entrepreneur from coastal villages across the country through successfully organizing trainings. The large-scale farming of this alga needs to be further strengthened and promoted by looking at potential socio-economic implication it offers for the inclusive economic growth in rural coastal settings. It would also help in the realization of the goal of doubling farmers' income by the year 2022. I sincerely believe that this manual will help new participants to practice seaweed cultivation more effectively. On behalf of CSIR and our Institute, I convey our best wishes for the successful implementation of the project.
-
Harmful algal blooms (HABs) have increased globally in recent years. In Hong Kong, a record algal bloom, caused by Gymnodinium mikimotoi and Gyrodinium sp. HK'98 (subsequently described as Karenia digitata) occurred in March and April 1998. Almost all fishes died in the affected cages, and the estimated economic loss caused by the HAB was HK$315000000 (equivalent to US $40000000). Most of the known toxic or harmful algal species are dinoflagellates. Some common dinoflagellate species such as Ceratium furca, Gonyaulax polygramma, Noctiluca scintillans, Heterocapsa triquetra, Prorocentrum minimum, Prorocentrum sigmoides, and Prorocentrum triestinum frequently bloom in Hong Kong waters. Others, such as Alexandrium catenella, Alexandrium tamarense, Gymnodinium mikimotoi, Gymnodinium cf. breve, Gymnodinium catenatum, Dinophysis caudata, Dinophysis acuminata, and Gambierdiscus toxicus bloom only occasionally, but their toxic effects or potentially toxic and harmful effects are very significant. Some important toxic and harmful, or potentially toxic and harmful dinoflagellate species are described. Among them, Gambierdiscus toxicus, a potential ciguatera fish poison producing species, and Gymnodinium cf. breve, a neurological shellfish poison producing species were new records from Hong Kong waters.
-
Harmful macroalgal blooms (HMBs) have been increasing along China's coasts, causing significant social impacts and economic losses. Besides extensive eutrophication sustaining coastal seaweed tides, the stimuli and dynamics of macroalgal blooms in China are quite complex and require comprehensive studies. This review summarizes the distinct genesis, development and drifting patterns of three HMBs that have persistently occurred in China's coastal waters during recent years: transregional green tides of drifting Ulva prolifera in the Yellow Sea (YS), local green tides of multiple suspended seaweeds in the Bohai Sea and large-scale golden tides of pelagic Sargassum horneri in the YS and East China Sea. While specific containment measures have been developed and implemented to effectively suppress large-scale green tides in the YS, the origin and blooming mechanism of golden tides remain unclear due to lack of field research. With the broad occurrence of HMBs and their increased accumulation on beaches and coastal waters, it is necessary to investigate the blooming mechanism and ecological impacts of these HMBs, especially with the growing stresses of climate change and anthropogenic disturbances.
-
The Maine Seaweed Council (MSC) produces this “Harvester’s Field Guide to Maine Seaweeds” as a supplement to their “Harvest Guidelines for Maine Seaweeds.” The information in this Field Guide complements and supports the recommendations in the Guidelines. Using both documents, current and future harvesters will be able to make more informed choices about what, when, where and how they harvest – a crucial step towards sustainable harvesting in Maine, and the primary mission of the Maine Seaweed Council.
Pages
Marine Agronomy Group, CAFNRM, UH-Hilo
200 W. Kawili st., HI 96720, USA
Contact: Marine.Agronomy.Group@gmail.com
Funding for this web portal is provided by the World Wildlife Fund and the University of Hawaii-Hilo.