Figure 2.

Halobates sericeus adult and juvenile numerical concentration (NC) versus microplastic NC in 1972–1973 (a: Spearman rank correlation, p = 0.3644; r² = 0.019) and 2009–2010 (b: Spearman rank correlation, p < 0.0001; r² = 0.404); H. sericeus egg NC versus microplastic NC in 1972–1973 (c: Spearman rank correlation p = 0.0614; r² = 0.079) and 2009–2010 (d: Spearman rank correlation, p < 0.0001; r² = 0.512). Also shown are size–frequency histograms for all microplastic particle areas (grey) and particles with attached eggs (black) in (e) 1972–1973 and (f) 2009–2010. Symbols (a–d) represent dates of data collection: spring 1972 (grey diamonds), autumn 1972 (filled diamonds), winter 1973 (open diamonds), summer 2009 (filled circles) and autumn 2010 (open circles). Only particles in the size range used by H. sericeus were used to calculate microplastic NC (a–d). Eggs in the samples for (e) were dislodged from their original substrate (63%) are excluded from this figure.