Study

Protection effects on fish assemblages, and comparison of two visual-census techniques in shallow artificial rocky habitats in the northern Adriatic Sea

  • Published source details Guidetti P., Verginella L., Viva C., Odorico R. & Boero F. (2005) Protection effects on fish assemblages, and comparison of two visual-census techniques in shallow artificial rocky habitats in the northern Adriatic Sea. Journal of the Marine Biological Association of the United Kingdom, 85, 247-255.

Actions

This study is summarised as evidence for the following.

Action Category

Manage or restrict harvesting of species on subtidal artificial structures

Action Link
Biodiversity of Marine Artificial Structures

Cease or prohibit all types of fishing in a marine protected area

Action Link
Marine Fish Conservation
  1. Manage or restrict harvesting of species on subtidal artificial structures

    A site comparison study in 2002–2003 on three subtidal breakwaters on open coastline in the Adriatic Sea, Italy (Guidetti et al. 2005; same experimental set-up as Guidetti, Bussotti & Boero 2005) found higher fish species richness and different fish community composition around a breakwater with restricted harvesting, compared with two unrestricted breakwaters, while fish abundances varied depending on the species and survey date. Sixteen years after harvesting restrictions were introduced, the fish species richness was higher around the breakwater with restrictions (24–27 species/breakwater) than those without (13–22/breakwater) and the fish community composition differed in seven of eight comparisons (data reported as statistical model results). Total fish abundance was higher around the restricted breakwater in only one of four surveys (152 vs 63–66 individuals/survey) but was similar in three (319–554 vs 192–841/survey). However, the individual abundances of eight of 12 fish species were higher around the restricted breakwater during two or more surveys (see paper for full results). Three fish species recorded around the restricted breakwater were absent from unrestricted breakwaters. Harvesting species on and around a boulder breakwater was restricted by creating a marine protected area in 1986, making fishing illegal with successful enforcement. Fishes were counted during four surveys at 4–7 m depth in 2002–2003 around the breakwater with restricted harvesting and around two nearby breakwaters with no restrictions.

    (Summarised by: Ally Evans)

  2. Cease or prohibit all types of fishing in a marine protected area

    A site comparison study in 2002–2003 of three areas of artificial rock in the Adriatic Sea, Italy (Guidetta et al. 2005, same experimental set-up as Guidetta, Bussotti & Boero 2005) found that a breakwater in a marine protected area where all fishing was prohibited for 16 years had a different fish assemblage, a higher species richness, and a similar total fish density but higher density of commercially targeted fish species, compared to two unprotected fished breakwaters. The fish assemblage at the unfished breakwater differed to both fished breakwaters in three of four sampling times, and only one in the final sampling time (data reported as statistical results and graphical analysis). In all four sampling times, species richness was higher at the unfished breakwater (24–27) than fished ones (13–22). Overall fish density was higher at the unfished breakwater in only one of four sampling times, however the individual densities of eight of 12 commercially targeted species were higher at the unfished breakwater in two or more sampling times, and schooling fish density was higher in all four sampling times (data reported as statistical results). The Miramare marine protected area was designated in 1986 and a fishing ban is successfully enforced. Four surveys using two different methods were undertaken from spring 2002 to summer 2003 at one breakwater in the Miramare Marine Protected Area (121 ha, no fishing since 1986) and two fished breakwaters (adjacent and 3 km away). Each sampling time, four transects (25 × 5 m) and four, point counts (5 m radius) were done per breakwater. The authors noted differences in the data between the two census methods.

    (Summarised by: Leo Clarke)

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 19

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 Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust