Long-term trends in juvenile American lobster populations across nine lobster fishing areas in Nova Scotia, Canada

Analyzing juvenile American lobster populations using fishery-independent data enhances understanding of population dynamics and supports fishery sustainability. This repeated cross-sectional study investigated trends in juvenile lobster populations by analyzing size distributions from nine Lobster Fishing Areas (LFAs) in Nova Scotia, Canada. Data were collected in season from lobsters sampled using ventless research traps between 2003 and 2023. Mixed effect linear and logistic regression models assessed spatial and temporal influences on mean carapace length (CL) and proportions of juvenile lobster. This study provides a 20-year overview of mean CL and juvenile probability, accounting for factors including water depth, sampling month, and lobster sex. Results showed significant variation in temporal effects on mean CL and proportion of juvenile lobster between LFAs. Decreasing trends in sampling juvenile lobsters were observed along the Northeastern coast of Cape Breton and in a highly productive area on the South Shore of Nova Scotia. In contrast, other LFAs showed more resilience, with the southwestern area displaying a relatively stable trend. The findings highlight variability in juvenile lobster trends across LFAs, which reflect the relative effectiveness of local management measures and provide insights to inform management decisions in Nova Scotia.