Marine amphipods as a new live prey for ornamental aquaculture: exploring the potential of Parhyale hawaiensis and Elasmopus pectenicrus

Abstract

Marine amphipods are gaining attention in aquaculture as a natural live food alternative to traditional preys such as brine shrimps (Artemia spp.). The use of Artemia is convenient for the culture of many marine species, but often problematic for some others, such as seahorses and other marine ornamental species. Unlike Artemia, marine amphipods are consumed by fish in their natural environment and show biochemical profiles that better match the nutritional requirements of marine fish, particularly of polyunsaturated fatty acids (PUFA), including eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. Despite their potentially easy culture, there are no established culture techniques and a deeper knowledge on the reproductive biology, nutritional profiles and culture methodologies is still needed to potentiate the optimization of mass production. The present study assessed, for the first time, the aquaculture potential of Parhyale hawaiensis and Elasmopus pectenicrus, two cosmopolitan marine gammarids (as per traditional schemes of classification) that naturally proliferate in the wild and in aquaculture facilities. For that purpose, aspects of the population and reproductive biology of the species were characterized and then a series of laboratory-scale experiments were conducted to determine amphipod productivity, the time needed to reach sexual maturity by hatchlings (generation time), cannibalism degree, the effects of sex ratio on fecundity and the effects of diet (shrimp diet, plant-based diet and commercial fish diet) on fecundity and juvenile growth. P. hawaiensis, unlike E. pectenicrus, was easily maintained and propagated in laboratory conditions. P. hawaiensis showed a higher total length (9.3 ± 1.3 mm), wet weight (14.4 ± 6.2 mg), dry weight (10.5 ± 4.4 mg), females/males sex ratio (2.24), fecundity (12.8 ± 5.7 embryos per female), and gross energy content (16.71 ± 0.67 kJ g-1) compared to E. pectenicrus (7.9 ± 1.2 mm total length; 8.4 ± 4.3 mg wet weight; 5.7 ± 3.2 mg dry weight; 1.34 females/males sex ratio; 6.5 ± 3.9 embryos per female; 12.86 ± 0.82 kJ g−1 gross energy content). P. hawaiensis juvenile growth showed a small, but significant, reduction by the use of a plant-based diet compared to a commercial shrimp and fish diet; however, fecundity was not affected, supporting the possible use of inexpensive diets to mass produce amphipods as live or frozen food. Possible limitations of P. hawaiensis could be their quite long generation times (50.9 ± 5.8 days) and relatively low fecundity levels (12.8 ± 5.7 embryos per female). With an observed productivity rate of 0.36 ± 0.08 juveniles per amphipod couple per day, P. hawaiensis could become a specialty feed for species that cannot easily transition to a formulated diet such as seahorses and other highly priced marine ornamental species.

Marine amphipods (Parhyale hawaiensis) as an alternative feed for the lined seahorse (Hippocampus erectus, Perri 1810): nutritional value and feeding trial

“…Amphipods (P. hawaiensis) were collected as previously described in Vargas-Abúndez et al (2021). Specifically, they were collected both from outdoor flow-through systems in which amphipods grow freely at aquaculture facilities of the National Autonomous University of Mexico (UNAM) located in Sisal, Yucatán, México, and from green intertidal algae attached to rocks in Sisal beach.…”

“…Plastic mesh was introduced in the tank as artificial substratum for the animals (Baeza-Rojano et al, 2013a;Vargas-Abúndez et al, 2021). Amphipods were fed daily with a commercial shrimp feed (Camaronina 35Ò Purina, Sonora, Mexico) (crude protein 350 g kg −1 , lipids 80 g kg −1 , ash < 100 g kg −1 , fiber < 50 g kg −1 , energy 21.6 kJ g −1 , FA profile not available).…”

“…Although diet and environmental parameters can influence their nutritional value, they are generally rich in proteins (up to 60% of dw) and lipids (up to 20% on dry weight (dw) basis), including the PUFAs (over 50% of total FAs in some species) EPA (over 20% of total FAs) and DHA (up to 20% of total FAs) Fernandez-Gonzalez et al, 2018;Jiménez-Prada et al, 2018). The few studies to assess and develop potential culturing or harvesting techniques for aquaculture conducted so far are promising (Guerra-García et al, 2016;Fernandez-Gonzalez et al, 2018;Xue et al, 2018;Vargas-Abúndez et al, 2021). These include a recently published culture trial in biofloc systems (Promthale et al, 2021).…”

“…It inhabits marine coastal habitats such as rocky beaches, estuaries and mangroves, where it readily forms dense aggregations of up to 7,000 individuals m −2 (Poovachiranon, Boto & Duke, 1986;Paz-Ríos, Simões & Ardisson, 2013). Since the early 2000's, it has been attracting interest to the scientific community as a compelling crustacean model for biological research (Sun & Patel, 2019), due to their small size (6.12-11.83 mm, total length), fast growth (0.15 mm day −1 ), short life cycle (from newborn to adult in 50.9 ± 5.8 days), high fecundity (up to 35 embryos per female), translucent embryos and year-round reproduction (Vargas-Abúndez et al, 2021). It is amenable to experimental investigation and plenty of information and experimental tools, such as the complete genome and gene editing tools, are already available for this species (Kao et al, 2016;Sun & Patel, 2019).…”

“…It is amenable to experimental investigation and plenty of information and experimental tools, such as the complete genome and gene editing tools, are already available for this species (Kao et al, 2016;Sun & Patel, 2019). Propagation of P. hawaiensis under laboratory conditions is straightforward and well documented, with prospects for mass-scale aquaculture (Vargas-Abúndez et al, 2021). Taking advantage of its environmental tolerance, opportunistic behavior and detritivorous habits, P. hawaiensis could be an interesting candidate for mass production in biofloc systems.…”