Insufficient energy reserves are widely considered to be a primary factor contributing to high rates of early benthic phase mortality among benthic marine invertebrates, but this hypothesis has been based mostly on indirect, observational evidence, and remains largely untested. We therefore examined the role of initial energy reserves in regulating survivorship and growth during the early benthic phase. Recently settled or hatched individuals of six invertebrate species were collected from natural populations, maintained without food, and their survivorship was monitored. Contrary to expectations, starved individuals of all six species had high survivorship through the critical first 10 d of the early benthic phase, with half of the species experiencing <2% mortality, and the remaining three species experiencing only 6 – 12% mortality. For five of the six species, 50% mortality was reached only after ≥50 d of starvation. Additionally, no difference in short-term survivorship was detected among starved individuals of three different size classes (a proxy for energy reserves) of N. ostrina hatchlings. Finally, the effect of different durations of delayed feeding (0 – 50 d) on recovery (i.e. growth and survivorship) once food was made available revealed that duration of starvation prior to feeding can nevertheless have significant longer-term impacts on the proportion of individuals that survive or their ability to grow. Together, these findings suggest that depleted energy reserves are not a primary cause of high mortality at the start of the early benthic phase, as had previously been hypothesized. Levels of energy reserves did influence growth, however, suggesting a possible indirect influence on performance by leaving individuals vulnerable for longer periods.

Full listing of methodology related to the data in this file is given in the article published in Ecology and Evolution.
This study examined the role of initial energy reserves on early benthic phase (EBP) survivorship in six species of benthic intertidal invertebrates on the west coast of Vancouver Island, Canada: the barnacles Balanus glandula Darwin 1854 and Chthamalus dalli Pilsbry 1916, the mussel Mytilus trossulus Gould 1850, the snails Nucella ostrina Gould 1852 and Nucella lamellosa Gmelin 1791, and the crabs Petrolisthes cinctipes Randall 1840 and P. eriomerus Stimpson 1871. EBP individuals of the two Petrolisthes species could not be readily distinguished, so these were grouped together and designated as Petrolisthes spp. Animals were collected from rocky intertidal sites located in Barkley Sound. All experiments were conducted at the Bamfield Marine Sciences Centre the west coast of Vancouver Island from May to September of 2019. To experimentally control the energy reserves of EBP individuals, most experiments in this study involved rearing EBP individuals without food. In addition, body mass was also used as a proxy for energy reserves in one experiment to determine its influence on survivorship.