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
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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
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.
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Use an alternative commercial fishing method Action Link |
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Use a larger mesh size Action Link |
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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)
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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)
