Linking life-history traits, spatial distribution and abundance of two species of lugworms to bait collection: A case study for sustainable management plan.

Arenicola spp. are marine benthic polychaetes dug for bait by anglers. Without regulation, this activity can lead to the decrease of lugworms' population meanwhile affecting the physical characteristics of the beach and the biodiversity. Here, we identified through morphology and genetics two species of lugworms, Arenicola marina and A. defodiens, within a Marine Protected Area of the Eastern English Channel (France). For each species, abundance and spatial distribution were assessed using a stratified random sampling and interpolation at four studied sites, as well as some life-history traits. These data were compared to lugworms' collection data to estimate its sustainability and to provide potential management measures. At one site, A. marina was present in large numbers on the higher and middle shore, whereas A. defodiens occupied the lower shore. At the other sites, both species co-occurred on the lower shore, and A. marina individuals were less numerous and lacking recruits. Spawning periods for A. marina occurred in early autumn and in late autumn for A. defodiens. The size at first maturity of A. marina was at 3.8 cm of trunk length (between 1.5 and 2.5 years old). One site (Au) appeared in need for management when linking abundance data with bait collection, where harvest of both species represented ∼14% of the total amount of lugworms and was above the carrying capacity of the beach for A. marina. The retail value associated to lugworm harvesting within the MPA was estimated at the same level as the shrimp retail value. Our results highlight the need for some fishery regulations.