Ageing abandoned, lost, and discarded lobster fishing gear based on fouling assemblages

Abstract

Abstract Abandoned, lost, or otherwise discarded fishing gear (ALDFG) is a by‐product of many fisheries. ALDFG impacts extend beyond the targeted species and include by‐catch, habitat degradation, and increased plastic in the environment. In particular ALDFG such as lobster gear attracts a succession of fouling organisms, increasing species diversity and productivity. In Cape Cod Bay, Massachusetts, USA, a seasonal lobster gear closure occurs for the protection of North Atlantic right whales (Eubalaena glacialis), allowing for the removal of ALDFG. In this study, the percentage cover of fouling organisms on recovered gear was used to model the age of the recovered gear (of indeterminate age because of missing tags). Between 2017 and 2021, a total of 379 traps were photo documented, of which 223 were of known age (1–22 years) and 156 were of unknown age. The age of the unknown traps was modelled utilizing a random forest algorithm using traps with a known age as a training library. High correlations between modelled ages and known ages (R2 = 0.634, P < 0.001*) slightly underestimated the age of the traps by 1.2–1.8 years, but are sufficient for developing an age distribution. The majority (79%) of traps were recovered off Provincetown and averaged 10–11 years old. Approximately 50% of the traps recovered in Cape Cod Bay were deposited or lost between 2005 and 2010. Calculating the age of ALDFG aids in determining the loss rate of gear and in identifying high concentrations of untended gear that can be recycled or reused. This analysis allows practitioners to understand the scale of the problem, helps quantify the quantity of gear in the ocean, and helps identify the areas most affected. This information improves the effectiveness of removal efforts by focusing on discrete areas of recurring and recent gear loss.