Study

Reducing longline bycatch: the larger the hook, the fewer the stingrays

  • Published source details Piovano S., Clò S. & Giacoma C. (2010) Reducing longline bycatch: the larger the hook, the fewer the stingrays. Biological Conservation, 143, 261-264.

Actions

This study is summarised as evidence for the following.

Action Category

Use a different bait type

Action Link
Marine Fish Conservation
  1. Use a different bait type

    A replicated study in 2005–2007 in pelagic waters in the Mediterranean Sea, Italy (Piovano et al. 2010) found that changing the size of the bait on pelagic longlines did not reduce the unwanted catches of pelagic stingray Pteroplatytrygon violacea. Neither the size of bait size (small or large), or the absence of light attractors, had a significant influence on the number of stingrays captured (data reported as statistical results). However, average catch rates were lowest with circle hooks (1 stingray/1,000 hooks) compared to J shaped hooks, and larger J hooks had lower catches than smaller J hooks (large: 3–6, small: 6–8 stingray/1,000 hooks). A total of 97 experimental fishing sets (86,116 hooks) were done between June-October from 2005–2007 in the Strait of Sicily, on nine commercial vessels targeting mainly swordfish Xiphias gladius. Small baits were round sardinella Sardinella aurita and horse mackerel Trachurus trachurus (26 sets), and the large bait was mackerel (Scombridae) (71 sets). Hooks were J shaped (two small, one large) alternated with circle hooks (one size). Light attractors (battery operated and chemical light sticks) were deployed on 72 sets.

    (Summarised by: Natasha Taylor)

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