Oyster larvae as a potential first feed for small-mouthed ornamental larval fish

Abstract

Aquaculture of ornamental marine fish for the aquarium trade is a possible solution to the negative environmental impacts of wild collection. An impasse to the culture of many marine fish species is high larval mortality due to unsuitable live feeds. Common live feeds can be too large for ornamental species, which often have larvae with small mouths. We tested wild oyster larvae as an alternative live feed for first-feeding blue tang Paracanthurus hepatus. P. hepatus readily consumed oyster larvae but did not consume rotifers. Survival and growth of P. hepatus fed oyster larvae was similar to unfed controls, likely due to the oyster trochophores developing into indigestible veligers. Restricting the diet of P. hepatus to only oyster trochophores improved survival and eye development, but survival rates remained low. Oyster trochophores were conditioned in pH 4.8 seawater to compromise their aragonite shells, and P. hepatus fed these had higher survival at 5 d post-hatch (dph) compared to those fed untreated trochophores and were the only fish surviving to 10 dph. The high consumption rates of oyster larvae by P. hepatus highlight the potential for bivalve larvae to be used as live feeds for first-feeding larval fish. Further research into improving the nutritional value of oyster larvae for larval fish may improve their viability as first feeds.

First feeding of a marine ornamental fish, the White‐barred Goby Amblygobius phalaena: Investigating the optimal initial live feed organisms and optimal feeding density

“…Consequently, they are well suited as initial live prey for marine ornamental fish larvae. Despite their potential, there have been limited instances of utilizing oyster larvae in the larviculture of marine ornamental fish: to our knowledge, only our study and the study by Basford et al (2019) have done so. Basford et al (2019) used New Zealand rock oyster Saccostrea glomerata larvae in the larviculture of Blue Tang Paracanthurus hepatus.…”

“…Despite their potential, there have been limited instances of utilizing oyster larvae in the larviculture of marine ornamental fish: to our knowledge, only our study and the study by Basford et al (2019) have done so. Basford et al (2019) used New Zealand rock oyster Saccostrea glomerata larvae in the larviculture of Blue Tang Paracanthurus hepatus. Therefore, further investigations into the application of oyster larvae in the larviculture of other marine ornamental fish species are warranted.…”

“…Therefore, in recent years, scientists have explored the use of various emerging, tiny (size = 60-80 μm) live feed organisms as initial prey to rear smaller-mouthed species. These include fertilized oyster eggs, oyster trochophores, ciliated protists, or copepod nauplii (Tarangkoon et al 2018;Basford et al 2019;Sowaske et al 2023).…”

Review: A bibliometric survey of live feed for marine finfish and shrimp larval production

“…This is why we hypothesize that the slow development of diversification in marine fish production is due, in part; to the limited exposure of new advances made within live feed research. Several live feed items besides the traditional Artemia and rotifers are used with various intensities, for example, polychaete larvae and molluscan veligers (see Howell, 1971 and Basford et al, 2019). However, these are far from well‐studied and their present volume rather limited relative to the also quite underused copepods.…”

“…Several live feed items besides the traditional Artemia and rotifers are used with various intensities, for example, polychaete larvae and molluscan veligers (see Howell, 1971 andBasford et al, 2019).…”