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Deposit-feeding sea cucumbers are efficient nutrient recyclers and have the potential to contribute to the limitation of organic matter load in polyculture or integrated aquaculture systems. Assessing how they assimilate organic matter originating from other farmed species is therefore important for the development of such multi-species farming systems. Here, a coupled stable isotope − fatty acid approach was used to characterize the assimilation of organic matter from shrimp (Penaeus stylirostris) farming by Holothuria scabra in an experimental culture system. H. scabra were reared in mesocosms on shrimp farming-originating sediment with and without additional food sources (maize and fish meals). Although fatty acid results did indicate that shrimp-farming sediment was assimilated by holothurids, we found no evidence of maize waste and fish meal contribution to H. scabra organic carbon (no effect on δ13C, no accumulation of meal-specific fatty acids). However, a strong effect of fish meal on H. scabra δ15N was observed, suggesting that this additional food source could represent an alternative source of nitrogen for holothurids. Finally, this study supports the culture of H. scabra as a perspective to reduce sedimentary organic matter excess associated with shrimp farms, and suggest that the addition of selected food sources might contribute to increasing the content in some nitrogen organic compounds in holothurid tissues. [ABSTRACT FROM AUTHOR]

Trade with marine species as ornamentals is an important sector of the international pet trade. The vast majority of these species are collected from the wild and one of the top supplying countries is Indonesia. Detailed evidence on trade with marine resources in Indonesia is lacking or it is hardly accessible. Moreover, the exploitation of ornamental species seems to be mostly uncontrolled. This study presents detailed characteristics of such trade for Indonesia, including the offered species, their sizes, prices, and conservation status, based on data and information obtained from wholesalers in 2018. The main provinces of marine wildlife collecting are also identified. In total, 777 marine vertebrate and invertebrate species were traded, belonging to 174 families including two species classified as endangered: Banggai cardinal fish (Pterapogon kauderni) and zebra shark (Stegostoma fasciatum). Commonly traded was red lionfish (Pterois volitans), known to be a successful invader. The volume of ornamental marine fish exported from Indonesia in period 2015–2019 was 3 353 983 kgs sold for 33 123 218 USD. The province of Bali was identified as the main exporter of ornamental marine fish within Indonesia. These findings should help to establish sustainable exploitation of marine resources in relation to conservation and wildlife management. [ABSTRACT FROM AUTHOR]

Age determination for stock assessments and conservation of cartilaginous fishes is mainly obtained by counting the annual growth bands in vertebrae. Recent studies show numerous inconsistencies and the need for systematic validation. We assessed the effectiveness of the fluorochrome alizarin red S, a common skeleton vital marker used as a time stamp for teleost fishes, on chondrichthyan. Twenty-five captive small-spotted catsharks (Scyliorhinus canicula) were marked by alizarin red S intraperitoneal injections. The fluorochrome produced a wide fluorescent mark on sectioned vertebral centra of all injected fish. Alizarin red S did not have a deleterious effect on growth during three months monitoring. The marks obtained remained stable in vivo for more than four years after injections and were resistant to fading during the observation under the microscope excitation light. Our results suggest that alizarin red S is an effective tool for long time vital marking of chondrichthyans. [ABSTRACT FROM AUTHOR]

This work examined diet composition of the juvenile orange-spotted grouper, Epinephelus coioides, and its trophic association with other juvenile fish species in tropical estuarine habitats during recruitment. From December 2015 to March 2016, juveniles were collected, their stomachs excised, preserved and analyzed. Small shrimps and amphipods, especially Grandidierella sp. and Elasmopus sp., were the most common food resources sharing among the most species. Epinephelus coioides predominantly ingested small shrimp, Grandidierella sp., Elasmopus sp. and fish larvae and had the greatest trophic overlap with Palatrus scapulopunctatus. Fish size, location and month significantly affected fullness indices and food items diversity in E. coioides. It is clear that the larger the size of E. coioides and its mouth opening, the larger the size of items ingested. This study confirms the ontogenetic dietary shift of juvenile E. coioides during recruitment season by starting as amphipod and small shrimp feeder and shifting to shrimp and fish larvae predator as they grow. This finding is fundamental to understanding how juvenile E. coioides cope with different conditions and its association with other co-existing species during the recruitment period. [ABSTRACT FROM AUTHOR]