Study

Trammel net and gill net selectivity for Lithognathus mormyrus (L., 1758), Diplodus annularis (L., 1758) and Mullus barbatus (L., 1758) in the Adriatic and Ligurian seas

  • Published source details Fabi G., Sbrana M., Biagi F., Grati F., Leonori I. & Sartor P. (2002) Trammel net and gill net selectivity for Lithognathus mormyrus (L., 1758), Diplodus annularis (L., 1758) and Mullus barbatus (L., 1758) in the Adriatic and Ligurian seas. Fisheries Research, 54, 375-388

Actions

This study is summarised as evidence for the following.

Action Category

Use an alternative commercial fishing method

Action Link
Marine Fish Conservation

Use a larger mesh size

Action Link
Marine Fish Conservation
  1. Use an alternative commercial fishing method

    A replicated, paired, controlled study in 1996–1997 of two coastal areas of the Mediterranean Sea, Italy (Fabi et al. 2002) found that a gillnet, a modified trammel net and a standard trammel net caught similar average sizes of striped sea bream Lithognathus mormyrus, annular sea bream Diplodus annularis and red mullet Mullus barbatus. Across areas and for the same mesh size, average sizes of all species were similar between the gillnet and trammel nets: striped bream (45 mm, gillnet: 16–17 cm, trammel nets: 16–18 cm; 70 mm, gillnet: 25–26 cm, trammel nets: 23–26 cm), annular bream (45 mm only, gillnet: 12–13 cm, trammel nets: 12–14 cm) and red mullet (45 mm only, gillnet: 16 cm, trammel nets: 15–16 cm). Between March 1996 and June 1997, a total of 29 trials were carried out in the Adriatic and 43 in the Ligurian Sea. A gillnet with one monofilament panel, a trammel net with an inner panel of polyamide monofilament and outer panels of twisted polyamide filament, and a standard commercial trammel net with all panels made of twisted polyamide filament, were tied end-to-end and their positions changed for each trial. The nets were lowered into shallow (4–15 m) water at dusk and retrieved the following dawn. All fish were identified, and fish length measured.

    (Summarised by: Rosslyn McIntyre)

  2. Use a larger mesh size

    A replicated, paired study in 1996–1997 in two areas of sandy-muddy seabed in the Mediterranean Sea, Italy (Fabi et al. 2002) found that an increase in the mesh size of set nets (gill and trammel) improved size-selectivity and reduced catches of small striped seabream Lithognathus mormyrus than a smaller mesh size. Across areas and nets, net selectivity (measured as optimal catch size) and average seabream length in catches increased with the larger 70 mm mesh size compared to the smaller 45 mm mesh size (selectivity, large: 26 cm, small: 17 cm; average length, large: 23–26 cm, small: 16–18 cm). In addition, the authors reported that the net selectivity for both mesh sizes was higher than the size at first maturity of striped seabream (14 cm), and that there were hardly any individuals under this size caught in the larger mesh, and between <1–3% for the smaller mesh size. Data were collected between March 1996 and June 1997 from set net deployments in the Adriatic Sea (29 trials) and Ligurian Sea (43 trials). Two mesh sizes (45 mm and 70 mm) mesh were tested simultaneously on each of three set net gears: a gillnet, a monofilament trammel net and a standard commercial trammel net. The three nets (each with two different mesh sizes) were tied end to end and the position of each gear changed for each trial. Nets were lowered into shallow (4–15 m) water at dusk and retrieved the following dawn. All fish were identified, and individual lengths measured.

    (Summarised by: Rosslyn McIntyre)

Output references

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, terrestrial 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 18

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