Valter Kožul

Incidence of spinal deformities in natural populations of sandsmelt, Atherina boyeri (Risso, 1810) in the Neretva river estuary, middle Adriatic

Information is presented on the occurrence of spinal deformities in natural populations of sandsmelt, Atherina boyeri in the Neretva River estuary, middle eastern Adriatic. During 1998 and 1999, the spinal deformity levels varied between 2.02% and 10.30% in four samplings, and 3.58% in total catch. The spine is deformed in one to a few places from vertical to horizontal angles, and the deformities are visible on the fish body immediately after catching. The possible reasons for such deformities are discussed.

Preliminary information on feeding and growth of pompano, Trachinotus ovatus (Linnaeus, 1758) (Pisces ; Carangidae) in captivity

Although the chances of successfully farming Trachinotus ovatus on a commercial scale are limited by the low food conversion rates, this species deserves further applied studies on the basis of their quick adaptation to confinement and their tolerance of captivity conditions.

Additional records of Lobotes surinamensis, Caranx crysos, Enchelycore anatina, and Lagocephalus sceleratus (Actinopterygii) in the Adriatic Sea

Additional records of four fish species are reported from the Adriatic Sea are reported: Atlantic tripletail, Lobotes surinamensis (Bloch, 1790) (Perciformes: Lobotidae) ; blue runner, Caranx crysos (Mitchill, 1815) (Perciformes: Carangidae) ; fangtooth moray, Enchelycore anatina (Lowe, 1838) (Anguilliformes: Muraenidae) ; and silver- cheeked toadfish, Lagocephalus sceleratus (Gmelin, 1789) (Tetraodontiformes: Tetraodontidae). More evidence is needed to indicate establishment of populations of these species in the Adriatic Sea. Lessepsian migrant Lagocephalus sceleratus is the third Lessepsian fish species from the Adriatic Sea with more than one record.

The spawning, embryonic and early larval development of the green wrasse Labrus viridis (Linnaeus, 1758)(Labridae) in controlled conditions

Green wrasse, Labrus viridis (Linnaeus, 1758), is an endangered species in the southern Adriatic Sea, but it is also of interest for potential rearing in polyculture with other commercial species for the repopulation of areas where it is endangered or as a new aquaculture species. A parental stock of the green wrasse was kept in aquaria for six years. The spawning, embryonic and early larval development maintained under controlled laboratory conditions are described and illustrated. The average diameter of newly spawned eggs was 1.01±0.03 mm. Mature and fertilized eggs were attached to the tank bottom by mucus. Hatching started after 127 h at a mean temperature of 14.4±0.8°C. The average total length of newly hatched larvae was 4.80±0.22 mm. Absorption of the yolk-sac was completed after the 5th day when larvae reached 5.87±0.28 mm. Larvae were fed with the rotifers Brachionus plicatilis. The pigmentation of L. viridis larvae is similar to that of Labrus merula and Labrus bergylta, but the main differences between these species are in the size of larvae and the development time of the melanophores on the anal fin-fold (five days later than with L. merula) and on top of the head (nine days earlier than with L. merula).

IMPACT OF OOCYTE SIZE ON LHRHa INDUCEDOVULATION AND FERTILIZED EGG QUALITY IN SADDLED BREAM OBLADA MELANURA (LINNAEUS, 1758)

The objective of this study was to evaluate the effects of oocyte size and luteinizing hormone releasing hormone analogue (LHRHa) on ovulatory success in artificial fertilization. Vitellogenic females with maximum oocyte diameters 400-550 μm were repeatedly injected with LHRHa (20 μ g kg-1 per injection). Fish with maximum oocyte diameters 500 μm spawned within 48-54 h. These results demonstrate that injected LHRHa is effective for ovulation of saddled bream with maximum oocyte diameters >500μm.