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Lophelia pertusa, a cosmopolitan cold-water coral, offers potential for new palaeoclimate proxies. This study investigated its skeletal growth patterns to aid in this development. Corallite characteristics (calyx diameter, height, thecal width and banding) of L. pertusa sampled from oil platforms in the northern North Sea were examined. The mean distance between daughter polyps along a growth axis (27.4 ± 5 mm, SD) was equivalent to the estimated annual growth rate; hence, the polyps bud once a year. The majority of growth occurred in the first year when the characteristic trumpet shape of a corallite was formed, while the thecal wall thickened more consistently. Further examination of two polyps showed a dark growth band and centres of calcification along the full length of the inner theca, which represents early skeletal growth. Skeletal sampling adjacent to this area along sequential polyps shows promise as an annual chronology in these North Sea corals.

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Horse mussels Modiolus modiolus can occur in dense aggregations and form areas of ecological and biological significance. In the Bay of Fundy, Canada, aggregations of horse mussels are associated with flow parallel bedforms, and this area is under consideration for designation as a sensitive benthic area which would provide protective measures. Basic demographic information is required to inform the development of effective conservation and management strategies and although general life-history characteristics of M. modiolus are known, detailed quantitative demographic information on this population is limited. The objective of this study was to characterize the population structure of horse mussels in the Bay of Fundy and assess change in key demographic characteristics since the last study in this area in 1997/1998. There have been significant changes in the population since 1998: the 2017 population contains larger, older, mature individuals, with significantly more females; 35% of the current population is over 20 yr of age. Direct evidence that this population has been impacted by bottom-contact fishing gear was also observed. Consistent with M. modiolus populations worldwide, this population demonstrates life-history traits (e.g. slow growth rates, late age of maturity, long lifespan) that make it sensitive and susceptible to disturbance. Coupled with the knowledge that this population overlaps with significant fishing activity, this study supports the assumption that this population is vulnerable to bottom-contact fishing and that recovery from adverse impacts would be slow and uncertain.