Hidden Mortality: Bottom Trawling Challenges the Legal Protection of Vulnerable Marine Species

Abstract

Legal protection of species is a central conservation instrument, yet its effectiveness depends on limiting incidental harm. Bottom trawl fisheries are inherently nonselective and frequently capture nontarget species. This creates a legal–management inconsistency: Bottom trawling remains permitted, whereas protected-species statutes prohibit harm or disturbance. Reconciling these policies requires that capture of protected species be rare and strictly incidental. Using standardized bottom trawl surveys in the Israeli Mediterranean, where bottom trawl fishing is strictly regulated spatially and seasonally, we quantified hourly capture rates of legally protected taxa. A mean of ∼53 protected individuals were captured per trawling hour, peaking at 80 m depth (147.7 individuals h⁻¹), dominated by Pennatula rubra. Elasmobranchs were also captured (∼2.6 individuals h⁻¹), including vulnerable, endangered, and critically endangered species. These results suggest that even under stringent regulation, species-focused protection may be insufficient where bottom trawling persists. Precautionary interaction-reducing measures, including stronger spatial restrictions, are therefore required.