MEPS 630:137-148 (2019)  -  DOI: https://doi.org/10.3354/meps13127

ABSTRACT: Spiny lobsters have an extended pelagic larval development in oceanic waters, ending in a non-feeding post-larva that swims to coastal habitats to settle and molt to a benthic juvenile. The accumulation of energetic reserves by larvae is thought to be challenging, especially in tropical waters. We examined changes in fatty acid (FA) composition of the tropical Caribbean spiny lobster Panulirus argus for successive developmental stages sampled across the shelf and off the eastern Yucatan Peninsula, Mexico. Final-stage larvae accumulate considerable lipid reserves (26 ± 2.8% SD of dry weight), mostly saturated FAs (65.4 ± 2.1% of total FAs). Proportions of the FAs 14:0, 15:0, and 16:1n-7 tended to decrease from final larvae to settled juveniles, consistent with their use as a key energy source, although the dominant energy sources in all developmental stages were 16:0 and 18:0. In contrast, the percentages of 20:4n-6 (arachidonic acid) and 20:5n-3 (eicosapentaenoic acid) tended to increase with development, consistent with being conserved. Bacterial and flagellate FA markers dominated in final-stage larvae, indicating a microbial loop foodweb as the source of lipid reserves. Such foodwebs are characteristic of the oligotrophic waters in which the larvae of both sub-tropical and temperate spiny lobsters species are also found. Similarities in the accumulation and use of FAs between the tropical P. argus and spiny lobsters from cooler regions of the world suggest that their extended larval period is a means of acquiring sufficient energy reserves whilst feeding in oligotrophic oceanic waters.

KEY WORDS: Fatty acid profile · Fatty acid trophic markers · Lipid energy reserves · Microbial loop · Foodweb · Tropical spiny lobsters