Juvenile growth deficit as an early alert of cockle Cerastoderma edule mortality

In the population dynamics of bi-phasic marine invertebrates, fitness one stage in life a cohort affects that following stage. This effect makes prediction fate challenging. We conducted 22 yr monthly survey cockles Cerastoderma edule focussed on juvenile Two types years were distinguished terms longevity: low-mortality group (‘L’) and high-mortality (‘H’). The cockle shell lengths 0 + cohorts was higher L group, August September. A could hereby confidently be assigned to or H as soon August. Maximum abundance cohorts, parasite load, date recruitment did not discriminate groups, while an early for peak related group. maximum air temperature chl concentration July whereas minimum salinity during month September slightly lower years. Therefore, length under given threshold identified alert short lifespan cohort. long-term analysis contributes deeper understanding invertebrates. success juveniles is solely intensity mortality by predation, but also linked their fitness, growth rates appearing proxy.