First estimates of metabolic rate in Atlantic bluefin tuna larvae

Abstract

Atlantic bluefin tuna is an iconic scombrid species with a high commercial and ecological value. Despite their importance, many physiological aspects, especially during the larval stages, are still unknown. Metabolic rates are one of the understudied aspects in scombrid larvae, likely due to challenges associated to larval handling before and during respirometry trials. Gaining reliable estimates of metabolic rates is essential to understand how larvae balance their high growth needs and activity and other physiological functions, which can be very useful for fisheries ecology and aquaculture. This is the first study to (a) estimate the relationship between routine metabolic rate (RMR) and larval dry weight (DW) (mass scaling exponent) at a constant temperature of 26 C, (b) measure the RMR under light and darkness and (c) test whether the interindividual differences in the RMR are related to larval nutritional status (RNA/DNA and DNA/DW). The RMR scaled nearly isometrically with body size (b = 0.99, 0.60-31.56 mg DW) in contrast to the allometric relationship observed in most fish larvae (average b = 0.87). The results show no significant differences in larval RMR under light and darkness, suggesting similar larval activity levels in both conditions. The size explained most of the variability in RMR (97%), and nutritional condition was unrelated to the interindividual differences in routine metabolism. This is the first study to report the metabolic rates of Atlantic bluefin tuna larvae and discuss the challenges of performing bioenergetic studies with early life stages of scombrids.

Atlantic bluefin tuna spawn early to avoid metabolic meltdown in larvae

“…1c) (Reglero et al 2018b). The duration of the yolk-sac stage (Y ufera et al 2014, see Appendix S1) and the routine metabolic rate have only been measured at 25°C and 26°C, respectively (Blanco et al 2020, see Appendix S1), and we assume Q10 equal to 2 for both these rates (Peck and Moyano 2016, Fig. 1c).…”

Advancements in hatchery production of red snapper Lutjanus campechanus: Exclusive use of small strain rotifers as initial prey for larval rearing

“…Along with copepods, enriched rotifers have been used effectively as first feeding organisms for snapper species (Duray et al, 1996; Ibarra‐Castro et al, 2020), small mouth‐gape marine fish larvae (Alvarez‐Lajonchère et al, 1996; Geng et al, 2019; Wullur et al, 2011), and even challenging species that also exhibit rapid yolk‐sac absorption and high nutritional demand, such as scombrid larvae (Blanco et al, 2020; Kaji et al, 1999; Sawada et al, 2005; Stein et al, 2018). S‐strain rotifers are relatively easy to culture in large scale, compared to copepod species (Saillant et al, 2013).…”

Comparison of Metabolic Rates of Young of the Year Beluga (Huso huso), Sterlet (Acipenser ruthenus) and Bester Hybrid Reared in a Recirculating Aquaculture System

“…Standard metabolic rate (SMR) is defined for whole organisms exhibiting minimal functional activity, i.e., in the total absence of voluntary muscular movements and when no food was being digested or absorbed [6]. However, whenever subjects show some minor activity in a respirometer (swimming or maintaining position) many authors prefer the term routine metabolic rate (RMR), which includes a minor cost of the activity [7,8]. Generally, SMR is correlated with growth trajectories, maximum aerobic performance, and some behaviors [9,10] and has an important role in ecological fitness.…”