Using a sclerochronological approach to determine a climate-growth relationship for waved whelk, Buccinum undatum, in the U.S. Mid-Atlantic

Using growth rings observed in statoliths, the size-at-age relationship was modeled for waved whelk (Buccinum undatum) populations within the Mid-Atlantic Bight. A total of 45 sites in the Mid-Atlantic were sampled between 2016 and 2019 using a scallop dredge, and a subset of the whelk collected were aged (n = 318). Lab-reared individuals and back-calculation methods were used to fill missing juvenile observations. The Mid-Atlantic Bight population appears to differ in the fit of growth curves, compared to other assessed populations, due to a timing difference in hatching. Growth curves for whelk from the Mid-Atlantic Bight show that maturity is reached between 4 and 6 years of age. A statolith chronology spanning a 10-year period was developed using a mixed-effects modeling approach. The chronology was used to explore the influence of temperature variation on growth during ecologically relevant periods. Growth increased with higher annual temperatures however specific seasonal bottom temperature had varying effects on growth. Increasing bottom temperature during summer, the anticipated egg-development and hatching period in this region, resulted in an age-dependent decline in growth with a positive effect on younger whelk and a negative effect on older whelk growth. Higher summer temperatures provide larger time-windows for growth, facilitating increased growth in early life stages. It appears that whelk in this region possess sufficient growth plasticity to adapt to warmer conditions throughout the year, but increased warming during specific seasons may depress growth in older individuals, potentially affecting fitness and population persistence. Understanding these temperature-growth dynamics are critical for disentangling the effects of climate change on whelk growth, allowing for population predictions in the future.

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