The balancing act: Protein, lipid and seaweed dietary levels to maximize gonad quantity in a wild‐caught sea urchin

Abstract

Sea urchin gonads (roe) are a prized global sea food commodity, with growing demand driving the need for urchin roe enhancement aquaculture. Effective roe enhancement of urchins using formulated feeds require species‐specific optimization and an understanding of the interactions between key dietary components (e.g. protein, lipid, carbohydrate, energy and/or algal supplements). Here, we tested 18 formulated feeds on the sea urchin Heliocidaris erythrogramma, collected from barrens. The 18 iso‐energetic (~20 MJ/kg) feed combinations contained one of three protein levels (250, 375 or 500 g/kg), three lipid levels (73, 101 or 131 g/kg) combined with a single (45 g/kg Sargassum spp.) or multiple (45 g/kg Sargassum spp., 25 g/kg Solieria robusta, 25 g/kg Ulva lactuca) dried algal supplement. From two consecutive 12‐week enhancement trials, the most optimal feed type contained 375 g/kg protein, 73 g/kg lipid and a 45 g/kg algal supplement (Sargassum spp.) and produced gonad indices of 18.5 ± 0.4% (Trial 1) and 21.7 ± 1.2% (Trial 2). Across feed types, there was no significant difference in the proportion of marketable quality (A and B grade) roe produced (56%–85% Trial 1, 65%–85% Trial 2). We conclude that roe enhancement of H. erythrogramma collected from barrens is highly feasible.

Aquatic Plants and Aquatic Animals in the Context of Sustainability: Cultivation Techniques, Integration, and Blue Revolution

“…These selected macroalgae-dryadditives significantly increased the growth performance, feed intake, energy, and protein consumption of T. gratilla [176]. At different protein and lipid levels, the dried seaweed (Sargassum spp., Solieria robusta, and U. lactuca) were used, as a single or multiple, as a feed additive to the diet of sea urchin (Heliocidaris erythrogramma), which improved gonad indices [177].…”

Modest Dietary Protein Requirement for Sea Urchin Gonad Production Demonstrated by Feeding Trials with Consideration of Protein Leaching

“…Sea urchins densely distributed on "barrens" (e.g., [11,12]), where communities of crustose coralline red algae without erect macrophytes occur in subtidal rocky seafloors, exhibit decreased growth rate and have small gonads with inferior quality (e.g., [13,14]). Recently, utilization of barren individuals of Mesocentrotus nudus in Northern Japan [15][16][17], Heliocidaris erythrogramma in Australia [18][19][20], and Strongylocentrotus droebachiensis in Norway [21,22] have been concentrated. In particular, M. nudus commands the highest price of all edible sea urchins around the world [23].…”