Study

Steeper biomass spectra of demersal fish communities after trawler exclusion in Sicily

  • Published source details Sweeting C.J., Badalamenti F., D'Anna G., Pipitone C. & Polunin N.V.C. (2009) Steeper biomass spectra of demersal fish communities after trawler exclusion in Sicily. ICES Journal of Marine Science, 66, 195-202.

Actions

This study is summarised as evidence for the following.

Action Category

Cease or prohibit mobile fishing gears that catch bottom (demersal) species and are dragged across the seafloor

Action Link
Marine Fish Conservation
  1. Cease or prohibit mobile fishing gears that catch bottom (demersal) species and are dragged across the seafloor

    A replicated, site comparison study in 2004–2005 of three gulfs in the Mediterranean Sea, Sicily (Sweeting et al. 2009) found that 15 years after bottom-towed fishing gear (commercial trawling) was banned in an area, total fish biomass but not average fish weight was higher compared to gulfs where trawling was permitted. The total biomass of fish was higher in the non-trawled gulf than in the two trawled gulfs, and differences were greatest in smaller size classes (data reported as normalised biomass spectra analyses). Average fish weight was typically similar in non-trawled (61–89 g) and trawled gulfs (62–70 g), except for significantly greater average weight in spring. However, more than 70% of fish above 500 g were from the non-trawled gulf. A ban on trawl nets and all other bottom-towed fishing gear in a 200 km2 area was implemented in the Gulf of Castellammare, 200 km west of the trawled gulfs, in 1990. Fishing with static gears (trammel and gillnets) by artisanal vessels within the trawl exclusion area continued. All gulfs were subject to the existing country-wide ban on trawling in water <50 m. Fish surveys were carried out over four consecutive seasons in the trawl exclusion gulf from 2004 and in the two trawled gulfs in autumn 2004 and spring 2005. Bottom-dwelling fish were sampled with a benthic otter trawl. At each gulf, random sampling within several 2.25 nm2 areas, at three depths, was done and lengths and weights of all fish recorded.

    (Summarised by: Natasha Taylor)

Output references
What Works 2021 cover

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 21

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.


Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape ProgrammeRed List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Mauritian Wildlife Supporting Conservation Leaders
Sustainability Dashboard National Biodiversity Network Frog Life The international journey of Conservation - Oryx Cool Farm Alliance UNEP AWFA Bat Conservation InternationalPeople trust for endangered species Vincet Wildlife Trust