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The growth pattern of the endemic Neretvan roach, Rutilus basak from the Hutovo Blato wetlands was analyzed. A total of 441 specimens ranging from 6.0 to 21.7 cm TL were obtained by electro fishing between December 2007 and November 2008. The male:female ratio for all fish combined was 0.34 : 1.00 but changed across length classes. The spawning period extended from February to April, with a peak in the first half of March. Maximum observed age was 10 years. Predominance of age classes 1-5 in the catch (77.0% of individuals) was noted. The length-weight relationship showed a positive allometric growth ( b = 3.321; R = 0.957). Parameters of the von Bertalanffy equation were: L = 20.201 cm; K = 0.257 per year; t = −1.554 year; R = 0.977. This study revealed that R. basak invests energy in reproduction rather than in body size and thus has a relatively fast growth, short life span and precocious maturity. Moreover, elementary biological population parameters are provided that can be used for conservation purposes. [ABSTRACT FROM AUTHOR]

The Neretva River Delta in Croatia is under constant threat of pollution from various sources along the river watercourse, such as the aluminium industry and bauxite mining, intensive agriculture and untreated sewage from towns. The area is also an important fishing ground and food source for the local residents, whereby the suitability of fish for human consumption is always in question. In this paper the presence of arsenic from six sources was analysed: in water, sediment and fish organs (kidneys, liver, muscles and gonads) of 11 fish species: Lepomis gibbosus, Carassius auratus gibelio, Cyprinus carpio, Anguilla anguilla, Ameiurus nebulosus, Mugil cephalus, Leuciscus svallize, Oncorhynchus mykiss, Salmo trutta, Tinca tinca and Scardinius plotiza. The research showed that arsenic concentrations varied significantly from one source to another in the water, sediment and organs of different fish species. Average concentrations in water and sediment were 18.1 μg L and 32.7 μg kg, respectively. Average arsenic levels in the fish organs were 115.9, 105.8, 76.1 and 61.9 μg kg in muscles, kidneys, gonads and livers, respectively. These values are below legally permitted concentrations, although individuals with higher than average concentrations were recorded. [ABSTRACT FROM AUTHOR]

A rare species, the angular rough shark Oxynotus centrina (Linnaeus, 1758) was incidentally captured on 7 July 2007 by long line in Croatian waters at the eastern coast of the Adriatic Sea. An adult female weighing 7883 g and reaching 800 mm in total length is the largest angular rough shark recorded to date not only in the Adriatic Sea but also in the Mediterranean. Morphometric measurements were taken which were in agreement with those of specimens previously measured from other Mediterranean areas. The female contained asymmetrically distributed (14 in the right ovary, four in the left) developing yellow yolk oocytes 24–35 mm in diameter, and the uteri were in resting phase. This confirms that vitellogenesis does not proceed in parallel with gestation and that the species reproduces in alternate years. Hepatosomatic and gonadosomatic indexes reached high values, 35.50 and 4.81, respectively. Examination of the stomach did not reveal traces of any recently eaten or even partly digested food, suggesting that the female was in a non-feeding period. [ABSTRACT FROM AUTHOR]

The present study investigated the age, growth, mortality and morphometry of the sand smelt, Atherina boyeri, in the Mala Neretva River estuary (mid-eastern Adriatic Sea). The study of scale annuli showed that the population is up to 4 years of age. However, most sand smelt are in their first and second year; the numbers of older individuals are very low because they migrate upstream and are heavily fished. The von Bertalanffy parameters for the total sample of sand smelt were found to be L∞ = 13.5 cm, K = 0.37 year-1 and t0 = −0 97. Overall total mortality was estimated at 1.81 year-1, natural mortality was 0.90 year-1 and fishing mortality was 0.91 year-1. [ABSTRACT FROM AUTHOR]

Early developmental stages of the hybrids Dentex (Dentex) dentex ... × Pagrus major ... and P. major ... × D. dentex ... were compared with those of the parental species. Fertilization rates were slightly different from those obtained with the parental fish. Two periods of mortality were noted, one immediately after fertilization and the other about 1 day before hatching. The mean hatching times of the hybrids and parental species were not significantly different (P ≤ 0.01). Growth of larvae from both maternal species and hybrids at the beginning of active feeding (day 6 after hatching) to day 30 was also not significantly different (P ≤ 0.01). One D. dentex ... × P. major ... hybrid reached a total length of 5.7cm at day 104; this specimen became highly cannibalistic, typical for the species. Descriptions of early stages of hybrids and their differences in terms of morphological features of parental species are presented. [ABSTRACT FROM AUTHOR]

The article offers information on the first record of leptocephali of bandtooth conger Ariosoma balearicum in the Adriatic Sea. Researchers caught the first sample of Arisoma balearicum accidently while conducting their monitoring project on small pelagic fish. Their observations regarding this speicies is described in the article.

The article presents the first record of Holacanthus ciliaris (Linnaeus, 1758) (Teleostei: Pomacanthidae) from the Mediterranean Sea. The queen angelfish Holacanthus ciliaris is a marine non-migratory subtropical fish that can be discovered inhabiting coral reef areas at dephts from 1 to 70 meter. Its previous distribution is the Western Atlantic and Eastern Central Atlantic.

The article focuses on the study which determined the world record morphometric measurements of bull ray species, known as Pteromylaeus bovinus, caught by fishermen in the Northern Adriatic Sea. The study used pelagic trawls method to catch the subtropical benthopelagic species of the family Myliobatidae at the muddy substrate and depths of the sea. An experimental result showed that the maximum record weight was 116 kilograms with no apparent parasitic infections described.

Length–weight relationships are presented for fish species from three eastern Adriatic estuarine systems (Croatian waters). The values of the parameter b mostly remained within the expected range of 2.5–3.5. No information regarding the length–weight relationship previously existed for 11 of the species. [ABSTRACT FROM AUTHOR]

The article offers information on the juveniles of two Lessepsian migrants, Fistularia commersonii Ruppell, and Siganus luridus. Researchers found their specimens in the Adriatic Sea. A chart of their physical properties which include length, body weight, and eye diameter, is included in the article.

The article presents information on the blue runner, Caranx crysos in the Adriatic Sea. It informs that the blue runner specimen from the Adriatic had an upper jaw with an irregular series of moderate canines flanked by an inner band. It was observed that the height of the spinous dorsal fin was distinctly shorter than the length of the soft dorsal fin lobe and the cleithrum margin was smooth, without papillae.

The article discusses on the characteristics of an oceanic puffer or tetraodontidae, which was first recorded in 1758 in the Adriatic Sea. It provides information on oceanic puffer's species and the oceans where oceanic puffers are usually located. The body parts of oceanic puffer were also measured and described.