The effect of escape vents on the capture of black sea bass, Centropristis striata, in fish traps

  • Published source details Shepherd G.R., Moore C.W. & Seagraves R.J. (2002) The effect of escape vents on the capture of black sea bass, Centropristis striata, in fish traps. Fisheries Research, 54, 195-207.


This study is summarised as evidence for the following.

Action Category

Modify fishing trap/pot configuration

Action Link
Marine Fish Conservation
  1. Modify fishing trap/pot configuration

    A replicated, randomised, controlled study in 1994 of an area of shallow seabed in the Atlantic Ocean off Delaware, USA (Shepherd et al. 2002) found that fish traps modified with escape vents reduced the unwanted catch of undersized black sea bass Centropristis striata compared to traps without escape vents. Across all escape vent sizes, catch rates of bass (all sizes) were lower in traps with vents than without (with: 2–11 bass/trap, without: 10–14 bass/trap) and the average bass size was greater (with: 27 cm: without: 25 cm). The proportion of undersized (<24 cm) bass in traps with vents was reduced by 72–95% compared to without, and the reduction increased with increasing vent size (2.9 cm: 288 bass, 3.2 cm: 80 bass, 3.5 cm: 59, 3.8 cm: 48 bass, no vent: 1,037 bass). Data were collected from 893 trap deployments (18–27 m) during nine trips between May-November 1994. Traps were deployed along lines (strings) of 25 traps in blocks of five trap designs, four with escape vents of different sizes (2.3 cm, 3.2 cm, 3.5 cm and 3.8 cm) and one standard trap without vents. Four strings of 25 traps were set/trip and traps were randomly positioned within a block. Strings were set 5 miles apart and left for 12–32 days before retrieval.

    (Summarised by: Chris Barrett)

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