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 There is an increasing interest in the use of Saccharina latissima (sugar kelp) as food, but the high iodine content in raw sugar kelp limits the daily recommended intake to relatively low levels. Processing strategies for iodine reduction are therefore needed. Boiling may reduce the iodine content effectively, but not predictably, since reductions from 38–94% have been reported. Thus, more information on which factors affect the reduction of iodine are needed. In this paper, sugar kelp cultivated at different depths were rinsed and boiled, to assess the effect of cultivation depth on the removal efficacy of potentially toxic elements (PTEs), especially iodine, cadmium, and arsenic, during processing. Raw kelp cultivated at 9 m contained significantly more iodine than kelp cultivated at 1 m, but the difference disappeared after processing. Furthermore, the content of cadmium and arsenic was not significantly affected by cultivation depth. The average reduction during rinsing and boiling was 85% for iodine and 43% for arsenic, but no significant amount of cadmium, lead, or mercury was removed. Cultivation depths determined the relative effect of processing on the iodine content, with a higher reduction for kelp cultivated at 9 m (87%) compared to 1 m (82%). When not taken into consideration, cultivation depth could mask small reductions in iodine content during rinsing or washing. Furthermore, since the final content of PTEs was not dependent on the cultivation depth, the type and extent of processing determines whether cultivation depth should be considered as a factor in cultivation infrastructure design and implementation, or alternatively, in product segmentation.

Enteric methane (CH4) is the main source of greenhouse gas emissions from ruminants. The red seaweeds Asparagopsis taxiformis (AT) and Asparagopsis armata contain halogenated compounds, including bromoform (CHBr3), which may strongly decrease enteric CH4 emissions. Bromoform is known to have several toxicological effects in rats and mice and is quickly excreted by the animals. This study investigated the transfer of CHBr3 present in AT to milk, urine, feces, and animal tissue when incorporated in the diet of dairy cows. Twelve lactating Holstein-Friesian dairy cows were randomly assigned to three treatment groups, representing the target dose (low), 2× target dose (medium), and 5× target dose (high). The adaptation period lasted seven days, and subsequently cows were fed AT for 22 days maximally. The transfer of CHBr3 to the urine at days 1 and 10 (10–148 μg/L) was found with all treatments. On day 1, CHBr3 was detected in the milk of most cows in the low and medium treatment groups (9.1 and 11 μg/L, respectively), and detected in the milk of one cow in the high treatment group on day 9 (35 μg/L). Bromoform was not detected in milk and urine at day 17, nor at concentrations above the detection limit in feces and collected animal tissues. Two animals (low) were sacrificed, and their rumen wall showed abnormalities. Upon histological examination, signs of inflammation became visible. Animals regularly refused the feed or distinctively selected against AT. In conclusion, within the confines of the present experiment, CHBr3 does not accumulate in animal tissue, but can be excreted in urine and milk.

Non-indigenous species (NIS) can be defined as species that colonized new geographical areas where they were not present previously. Their increasing appearance has been causing considerable ecological and economic problems globally. Under this scope, biological invasion and invaders’ success has been an important topic during the last decades. Hundreds of marine NIS have been introduced around the world and seaweeds (marine macroalgae) are a significant part of them. Studies conducted worldwide in the last decade have been reporting around 250 species of introduced seaweeds. The northeast part of the Atlantic is especially known to be home to many introduced species and more than 100 introduced species of seaweeds are reported in Europe. This thesis will go through the processes of seaweeds invasion, from their introduction stage and their introduction vectors, to their invasive success, focusing on the main NIS of seaweeds that can be currently found at the northwest of the Iberian Peninsula. Particularly, six NIS of seaweeds (Sargassum muticum, Grateloupia turuturu, Asparagopsis armata (including Falkenbergia rufolanosa stage), Undaria pinnatifida, Codium fragile subsp. fragile and Colpomenia peregrina) were previously selected and sampled – based on DAFOR (Dominant, Abundant, Frequent, Occasional or Rare) cover ranges scale – along intertidal sites located within the northwest of the Iberian Peninsula. As a result of the sampling, the distribution of those seaweeds has been updated for the area, producing a hotspot map of their presence and relative abundance. Furthermore, the environmental management of NIS was addressed, as well as their potential uses such as biofertilizers, bioactivities, feed and food, aiming to show how these species, which are jeopardizing the ecosystem, can be an excellent environmental resource of bioactive compounds with high industrial potential and high socio-economic revenue. 

A regional comparative assessment of reef resources and socioeconomic activities of fisheries in 17 Pacific island countries and territories (PICTs) conducted by the Secretariat of the Pacific Community (SPC) over an 8-year period (2002–09) reveals useful resource status information. Here we review the status of sandfish (Holothuria scabra) stocks from a range of PICTs, some of which have had a moratorium on commercial exports for many years. Holothuria scabra was present in 41% of countries and 23% of sites assessed, although sites with sandfish were mostly at low density, with 81% below the mean density of 1,200 individuals/ha, and the majority of sandfish were small (<23 cm body length).

Progress in community-based marine resources management in the past decade has done little to reverse the declining trend in sea cucumber fisheries for the production of the export commodity, beche-de-mer. Both customary marine tenure and fisheries regulations are used to manage sandfish resources across the Pacific region, but have limitations. Community-based management controls were often outside the traditional boundaries of subsistence fishing when trying to control commercial harvests, while fisheries agencies were limited in the resources available to devise and implement regulations. While there are some well-managed fisheries as well as prospects for recovery in fisheries that are under pressure, difficulties in enforcing commercial fishing and export controls, and unlimited exemptions on subsistence and domestic sales, are challenging the sustainability of this fragile resource.

Continued extraction of sandfish for export and subsistence use is causing local extinctions and depletion of broodstock, threatening the potential development of sandfish aquaculture. PICTs therefore face a big challenge to reverse current trends to ensure continued use and commercial return from sandfish resources. At present, aquaculture offers both a hope and, in some cases, further pressure on a stressed legal, social and ecological system. While aquaculture is being trialled in the region with some success, the introduction of relatively new technology is also resulting in direct (broodstock losses) and indirect (trial harvests and clearing to prepare ground for seed) depletion of wild stocks. Many fishers and managers in PICTs lack basic knowledge of sea cucumber biology and aquaculture technology. In the face of big promises from aquaculture investors in the region, SPC has provided advice to assist decision-makers in making the best choices for sea cucumber aquaculture development in their countries.