Appetite in captivity - feeding studies of the red sea cucumber Parastichopus tremulus

Abstract

The deposit feeding sea cucumber Parastichopus tremulus is an underutilised resource in North Atlantic waters. Geographically it is distributed from the Barents Sea in the north to the Canary Islands in the south. At present performance of P. tremulus in aquaculture is largely unknown. Species and stage specific biological knowledge gaps need to be filled for a potential industry to develop, and feeds that support growth needs special attention. Particulate matter (sludge) from fish farms is an unutilised resource that has potential as ingredient in feeds for sea cucumbers, which would help to reduce the environmental footprint of P. tremulus aquaculture production. The suitability of salmon sludge as a feed ingredient is unknown. Feeds using dried salmon freshwater sludge (50% and 75% volume ratios) or seaweed powder (Sargassum spp. 25%, 50% and 75% volume ratios) were compared in this study. Feed mixes with different ratios of ingredients and sand (0.6-1 mm) were given in excess (50% wet weight/wet weight animal/week) to adult P. tremulus. Daily feed intake was estimated by measuring daily faeces production rate. Each animal was given all feeds sequentially, and faeces collected for a ten-day period. Absorption efficiencies were estimated based on analysis of organic matter content in feed and faeces. Large variations were found in feed intake, both between individuals and between days. Our results indicated that P. tremulus showed a higher intake of feeds containing seaweed, with a trend of higher intake with increasing seaweed content. Absorption efficiency estimates of seaweed-based feeds ranged from -337 to 73.7%. P. tremulus showed a preferential selection of organic particles in the feed with lowest content of seaweed. Absorption efficiency of feeds containing sludge (2.5 – 58.3%) was comparable to that of feeds containing seaweed, however, feed intake of sludge-based feeds was significantly lower than that of the seaweed-based feeds and resulted in large variation in estimates. The results suggest that salmon freshwater sludge could have a potential future use as an ingredient in sustainable feeds for P. tremulus, but that optimisation of feed formulations need to be studied further.

Effect of live-storage period and temperature on oxygen consumption rate in the cold-water sea cucumber Parastichopus tremulus

“…Animals in group 1 and 2 were not supplied with feed other than what the incoming unfiltered seawater provided in form of organic matter. Group 3 on the other hand was fed regularly on a mixture of seaweed powder (Sargassum thunbergii) and sand at a ratio (volume:volume) of 50:50 (medium ration according to Sunde and Christophersen, 2023). All experiments were performed with standardized groups of sea cucumbers where one group consisted of three sub-groups (replicates) divided between three perforated plastic trays (L x W x H: 600 x 352 x 96 mm) with lids.…”

“…In Norway, the red sea cucumber Parastichopus tremulus has been identified as one of the species with the highest commercial potential for Asian markets (Kjerstad et al, 2015). P. tremulus has also been considered as a potential key species in Norwegian IMTA (Sunde and Christophersen, 2023). Presently only landed as bycatch, it is one of the most common sea cucumbers occurring along the Norwegian coast.…”

Aquaculture of emerging species in North-Eastern Atlantic and Mediterranean Sea: a systematic review on sea cucumber farming and potential development

“…Enriched substrates promoted higher growth rates compared with natural treatment, in both adult and juvenile specimens, but with similar survival rates (Rodrigues et al, 2023). In addition, while growth rates were high regardless of the ratio of sand to macrophyte, FR and AE increased with sediment enrichment (Sunde and Christophersen, 2023). Sediments enriched with seagrasses (Cymodocea nodosa and Zostera noltii) showed different performance, probably due to the composition of the seagrass litter (Domıńguez-Godino et al, 2020).…”

“…H. tubulosa showed high survival rates and positive growth with fish, mussels and sea urchins (Tolon et al, 2017a;Grosso et al, 2021Grosso et al, , 2023, but also showed signs of disease in highly eutrophic conditions, such as those that may occur near fish cages (Sadoul et al, 2022). Similarly, P. tremulus growth rates were enhanced by the addition of salmon sludge to natural sediments, suggesting the suitability of this species to reduce the impact of salmon farming, which is widespread in northern European countries (Sunde and Christophersen, 2023). Fish waste was also found to be palatable to H. forskali but further studies on growth performance are needed (MacDonald et al, 2013).…”