Vol.:(0123456789) Aquaculture International https://doi.org/10.1007/s10499-023-01055-1 1 3 Efect of shrimp farm efuent (SFE) on growth, survival, regeneration, and biochemical composition in indigenous red seaweed Gracilaria corticata var. cylindrica Santlal Jaiswar 1,2  · Pankaj S. Dawange 1,2  · Chetna M. Zala 1  · Nikunj Balar 3 Received: 18 August 2022 / Accepted: 26 November 2022 © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2023 Abstract The growth and biochemical profle of the red seaweed Gracilaria corticata var. cylindrica was evaluated after in vitro cultivation with efuent from a shrimp Litopenaeus vannamei farming pond. Seaweeds were cultivated for 21 days in sterilized seawater enriched with shrimp efuent with 5 diferent concentrations (0.1, 1, 10, 50, and 100 mL L −1 ). Frag- ments with 50 and 100 mL L −1 showed a higher signifcant growth rate of 3.53 ± 0.08% and 3.7 ± 0.55% respectively compared to sterilized seawater as control (2.5 ± 0.15%). Sur- vival and regeneration of fragments were higher in the treatments 10, 50 and 100 mL L −1 . A 100% survival was observed in 10 and 100 mL L −1 , while 100-mL L −1 showed 100% regeneration in fragments. The number of branchlets developed per fragment was observed higher (2.33 ± 0.52) and (2.23 ± 0.05) in 50 and 100 mL L −1 respectively. A 50 mL L −1 showed the highest (124.45 ± 9.28 µg g −1 ) chlorophyll-a, and 100 mL L −1 showed the highest (54.5 ± 5.42 µg g −1 ) chlorophyll-b content. Agar yield (2.8 ± 0.32% FW), total sugar (72.6 ± 2.7%), and 3,6-anhydrogalactose (8.77 ± 0.63%) was observed highest in 100 mL L −1 treatment of shrimp efuent, while sulphate content (1.5 ± 0.8%) found higher in 50 mL L −1 . Results showed that efuent treatments positively afected G. corticata var. cylindrica growth and biochemical composition, especially 50 and 100 mL L −1 , which could be considered a good bio-stimulator for the making of the seedling. This work pre- sents the potential use of efuents from shrimp cultivation as fertilizer, improving the growth and seedling production for sustainable cultivation of endemic red seaweed Graci- laria corticata var. cylindrica. Keywords Agarophyte · Gracilaria · Biofertilizer · Shrimp farming efuent · Growth Handling editor Ronan Sulpice * Santlal Jaiswar santlal@csmcri.res.in 1 Division of Applied Phycology and Biotechnology, CSIR-Central Salt & Marine Chemicals Research Institute, Gijubhai Badheka Marg, Bhavnagar 364002, India 2 Academy of Scientifc and Innovative Research (AcSIR), Ghaziabad 201002, India 3 Center for Agriculture Horticulture Development (TKF-PIL), Manar, Bhavnagar 364150, India