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The Effects of Salinity on the Survival, Growth, and Eco-Physiological Parameters of Juvenile Sea Urchin Diadema setosum
by
, , ,
Xuanliang Wang
1,
Jieyu Zhang
1
,
Lei You
1,
Yunyong Jin
1,
Zhenhao Lin
1,
Junhao Lin
1,
Jinhui Wu
2 and
Zonghe Yu
1,* 1
College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China
2
Agro-Tech Extension Center of Guangdong Province, Guangzhou 510520, China
*
Author to whom correspondence should be addressed.
Animals 2025, 15(16), 2462; https://doi.org/10.3390/ani15162462
Submission received: 15 July 2025
/
Revised: 16 August 2025
/
Accepted: 19 August 2025
/
Published: 21 August 2025
(This article belongs to the Special Issue Energy and Lipid Metabolism in Aquaculture Invertebrates: Mechanisms, Nutritional Modulation, and Applications)
Simple Summary
Diadema setosum holds both economic and ecological significance. Economically, it is not only valued for its medicinal properties but also for its gonad, which can be processed into various seafood products, making it an important commercial sea urchin species. Ecologically, D. setosum plays a vital role in maintaining marine ecosystem balance by feeding on algae and organic debris, thereby facilitating nutrient cycling and energy flow within benthic ecosystems. However, overfishing and environmental changes have led to a decline in its population. Previous studies have shown that salinity significantly affects the reproduction and larval development of D. setosum, but its impact on juveniles remains unclear. In this study, we investigated the effects of salinity on the survival, growth, and eco-physiological parameters of juvenile D. setosum. Our results demonstrate that salinity has a substantial influence, with an optimal range of 32–36. This work provides valuable insights for the breeding and aquaculture of D. setosum.
Abstract
Diadema setosum is an economically important species in tropical and subtropical waters. To determine the optimal salinity for D. setosum aquaculture, we examined six salinity levels (20, 24, 28, 32, 36, and 40) during winter and spring, assessing their effects on survival, growth, and eco-physiological parameters of juvenile D. setosum. Results showed that (1) in winter, the survival rate of juvenile D. setosum was highest at salinities of 28–36, with 100% survival at salinities of 32–36. During spring, all salinity groups reached 100% survival. (2) Juveniles exhibited optimal growth performances at salinities of 32–36 across all seasons, and negative growth occurred at lower salinities (20–24) during winter. (3) The juveniles exhibited higher oxygen consumption rate and ammonium excretion rate with an atomic O:N ratio > 25 at salinities of 32–36, indicating that carbon-based substrates were the primary catabolic substrate. Under salinity stress (<24 or >40), the O:N ratio declined significantly, reflecting that proteins were the main metabolic substrate. (4) Fecal excretion was higher in winter than in spring, possibly due to size and digestive efficiency differences. Studies confirmed that salinity and temperature exert significantly combined effects on D. setosum, with an optimal salinity range of 32–36. This work provides valuable insights for the breeding and aquaculture of this species.
Keywords:
Diadema setosum; juvenile; salinity; survival; growth; eco-physiological parameters
