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The seaweeds are a diverse group of large marine macroalgae that are as important to the marine world as land plants are to our terrestrial world.  Seaweeds were the precursors to land plants, and like land plants, they are critical primary producers, forming living links between the inorganic and the organic world, using photosynthesis to convert CO2 and nutrients into living biomass.  These primary producers support and encourage other marine life through the production of oxygen, contribution to marine food webs, and by providing structure and habitat for refuge, breeding, and nursery grounds for fish and invertebrates.  Seaweeds are an important resource for humans.  Coastal peoples have always utilized seaweeds for food, minerals, medicine, fertilizer and fodder, and these sea-plants continue to provide for an everincreasing world population.  A multi-billion dollar industry worldwide, seaweeds are consumed as nutritious sea vegetables, processed to extract valuable phycocolloids including agar, carrageenan, and alginate, and utilized in the agricultural industries for animal fodder or plant fertilizers.

A significant challenge to the expansion of aquaculture production is controlling the outbreak of disease. Many farmers who experience the potential loss of stock from disease may choose to use chemotherapeutic agents to minimize their loss. It is generally understood that a disease in aquaculture is a combination of the health of the animal, the condition of the environment and the presence of a pathogen. From this concept there are a number of precautionary measures that farmers may practice to minimize disease outbreaks. The principles of Hazard Analysis Critical Control Point (HACCP) may be useful risk management tools to reduce pathogens, animal stress and the need for chemotherapeutic agents to control disease outbreaks on the farm.

Discussion on:

1. Nutrient releases from salmon aquaculture
2. Impacts on pelagic ecosystems
3. Pelagic nutrient and ecosystems impacts of salmon aquaculture in Chile, with emphasis on dissolved nutrient loading and harmful algal blooms
4. Salmon aquaculture and harmful algal blooms (HABs)
5. Nutrient impacts of salmon aquaculture on Chilean lakes

The expansion of the global macroalgal aquaculture and climate change creates the need for germplasm preservation of valuable aquaculture strains and maintenance of natural biodiversity. Compared to the large number of studies in fish and shellfish species, relative few studies have been conducted on the macroalgal germplasm cryopreservation. The first cryopreservation of macroalgae to −75 °C was reported on Neopyropia tenera (formerly called Porphyra tenera) in 1964. To date, a total of 34 studies reported germplasm cryopreservation in 33 species, including Chlorophyta (7 species), Ochrophyta (14 species), and Rhodophyta (12 species). The goal of this review was to summarize the published studies on macroalgal germplasm cryopreservation, compare the reported protocols for the cryopreservation process, and identify the factors affecting post-thaw viability. Overall, macroalgal germplasm cryopreservation included haploid or diploid thalli, spores, and gametes. Cryotubes (1.5-ml or 2-ml) have been widely used to package germplasm samples for cooling and storage in most studies, and the 0.5-ml straws and 5-ml cryotubes have been used in several studies. Two approaches (programmable controlled cooling and vitrification) were employed for macroalgal germplasm cryopreservation. A two-step programmable controlled cooling (e.g., from initial culture temperature to a frozen temperature, such as −40 °C, and then directly plunging into liquid nitrogen at −196 °C) was determined to be an effective cooling strategy. Vitrification, a super rapid cooling for a sample to form non-crystalline amorphous solid, was applied on macroalgal germplasm cryopreservation with sample encapsulation and dehydration. Survival of post-thaw samples varied significantly in different studies. Based on research updates, recommendations are made for future research. It is expected that this review can serve as a foundation for future germplasm banking of macroalgae for aquaculture and biodiversity preservation.