MEPS 579:55-66 (2017)  -  DOI: https://doi.org/10.3354/meps12246

ABSTRACT: Variability in motility of planktonic larval marine benthic invertebrates with environmental conditions can affect the dispersal and survival of individuals by its influence on encounters with food and predators, horizontal transport, and settlement. We quantified the swimming speed and directional persistence, expressed as a persistence time and persistence length (i.e. run duration, and run length of a random walker), of nauplii and cyprids of the acorn barnacle Semibalanus balanoides over a temperature range of 0 to 12°C. We fit persistence time and length parameters in a correlated random walk model to displacement data obtained from video-recordings in 2D (horizontal and vertical dimensions). Nauplii (stages 2 and 6) were generally characterized by lower swimming speeds (nauplii: 0.98 to 2.54 mm s^-1; cyprids: 2.56 to 3.19 mm s^-1), higher persistence times (nauplii: 1.18 to 5.49 s; cyprids: 0.29 to 0.92 s), and higher persistence lengths (nauplii: 1.52 to 11.12 mm; cyprids: 0.96 to 2.80 mm). Significant correlations between temperature and persistence length resulted from the effect of temperature on swimming speed for stage 6 nauplii and persistence time for cyprids. Analyses indicated directional bias of each swimming metric in the vertical dimension. Although the correlated random walk model is an idealized model of animal movement, we suggest that the quantification of directional persistence of larval marine benthic invertebrates can provide new insight into the evolutionary trade-offs associated with feeding and non-feeding life history strategies.

KEY WORDS: Swimming speed · Random walk · Motility · Larval barnacle · Cypris · Nauplius · Meroplankton