Length–weight relations are presented for 20 fish species caught by small-scale fishery from the southern Ionian Sea (Greece) including a marine protected area from 2013 to 2017. The following species were studied: Spicara maena (Linnaeus, 1758); Labrus merula Linnaeus, 1758; Symphodus tinca (Linnaeus, 1758); Xyrichtys novacula (Linnaeus, 1758); Mullus surmuletus Linnaeus, 1758; Phycis phycis (Linnaeus, 1766); Sparisoma cretense (Linnaeus, 1758); Scorpaena scrofa Linnaeus, 1758; Serranus scriba (Linnaeus, 1758); Siganus luridus (Rüppell, 1829); Diplodus sargus (Linnaeus, 1758); Diplodus vulgaris (Geoffroy Saint-Hilaire, 1817); Pagellus acarne (Risso, 1827); Pagellus erythrinus (Linnaeus, 1758); Pagrus pagrus (Linnaeus, 1758); Spondyliosoma cantharus (Linnaeus, 1758); Dentex dentex (Linnaeus, 1758); Synodus saurus (Linnaeus, 1758); Trachinus radiatus Cuvier, 1829; Uranoscopus scaber Linnaeus, 1758. The main fishing gears that were involved in the data collection were trammel nets and longlines that were set in the sea during all seasons of the year. A total of 3510 specimens belonging to 12 families were examined. For two species (Labrus merula and Xyrichtys novacula) the maximum total body length reported in our study was higher than the one reported in the literature. To our knowledge, the length–weight relations for all the 20 fish species are the first to be reported from this area. Thus this contribution can serve as a baseline for monitoring, conservation and management efforts in this region, which is well known for its prime ecological importance. 

ichthyofauna, morphometric relations, length–weight relation, LWR, marine protected area, Zakynthos