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.

In this study, the effects of feeding (F) and starvation (S) on survival, injury, and weight of captive male snow crab were examined. The experiment was carried out with three replicates of each treatment. Each replicate had 11 individually tagged crabs (average weight of 650 g ± 37 SE) per tank (replicate) in a total of six circular tanks (500 L), with stocking densities of 14 kg/m. The experiment ran for 100 days and the animals were exposed to ambient seawater temperatures ranging from 4.4ºC to 5.4ºC during the trial period. There were no significant differences in wet weight between the groups at the start or at the end of the experiment. However, the hepatopancreas index (HI) significantly decreased in both groups from 6.1% at the start to, respectively, 4.6% (F) and 3.2% (S) at day 100. The S group had a significantly lower HI than the F group. Only one animal died during the experiment (day 100, F). The frequencies of injuries were similar in all groups. The results show that adult male snow crab can be stored for minimum 100 days (with or without feeding) with relatively low risk of physical injury, or mortality due to social interactions.

The effects of water velocity and tipping frequency (water movement) on survival, somatic and gonad growth of juvenile and adult green sea urchin, Strongylocentrotus droebachiensis were investigated. Juvenile and adult urchins were held in ‘laminar’ or ‘tipper’ tanks. Both were supplied with three inlet water flows (1.5, 3.0 and 7.5 L min⁻¹) which converted to water velocities of 0.28, 0.57 and 1.43 cm s⁻¹ in the ‘laminar’ tanks and tipping frequencies of 30, 10 and 5 s in the ‘tipper’ tanks. Juvenile sea urchins had significantly lower mortality and greater somatic growth when held in ‘laminar’ flow tanks compared with ‘tipper’ tanks. The varying water velocities tested in the ‘laminar’ flow treatment had no effect on the growth of juvenile sea urchins. The juvenile sea urchins in the ‘tipping’ treatment held at high tipping frequency had significantly slower growth than those in the medium and low tipping frequency treatments. There were no differences in mortality or gonad growth in the adult sea urchins regardless of treatment. The ‘laminar’ flow tanks retained significantly more organic material compared with the ‘tipper’ tanks. The authors discuss the effects of water velocity and tipping frequencies in system design for aquaculture of sea urchins.

The snow crab (Chionoecetes opilio) is one of the most important commercial crabs in the world; it is heavily exploited in Atlantic Canada, Alaska, the Sea of Japan and the Barents Sea. Catches in the Barents Sea north of Norway have increased dramatically in the last decade. Most of the world's catch is processed, frozen and exported overseas. However, recently there has been considerable interest in exporting live snow crab, particularly in Norway. The stress of capture and live transport can result in significant mortalities. In order to establish a live export industry for snow crab, the welfare of the animal must be monitored throughout all the steps of the live transport process. In this study the reactions of snow crabs exposed to increasing periods of air exposure were measured in terms of reflex indicators, incidence of mortality, blood lactate levels and blood protein and haemocyanin. Although this is not a specific live holding or live transport process the aim was to test the suitability of reflex indicators to reflect vitality (stress) and not just to predict mortality. This would be compared with traditional blood biochemistry techniques for measuring crustacean stress. The study demonstrated that the reflex index score (RIS) is suitable to assess the vitality of snow crab. Longer air exposure periods render higher mortality rates and less vital individuals. The authors believe using vitality reflex indicators would be a suitable way of measuring crab welfare during the live holding and transport process.