aqua International Journal 21(4)
Volume 21, Issue 4 – 15 October 2015
Shima Bakhshalizadeh, Ali Bani1 and Shahram Abdolmalaki: Growth traits of two sturgeon species, Acipenser gueldenstaedtii and Acipenser nudiventris, in the Iranian waters of the Caspian Sea, pp. 154-164
The life history traits of the Russian sturgeon, Acipenser gueldenstaedtii, and ship sturgeon, Acipenser nudiventris, obtained from Iranian coastal waters of the Caspian Sea, were studied through analysis of the pectoral fin spine section. The specimens were obtained from commercial fisheries between October 2008 and June 2010.The interpretation of growth bands in the pectoral fin spine sections was carried out objectively using the direct reading of thin sections and by image analysis. The maximum age recorded for the specimens of Russian sturgeon and ship sturgeon were 27 and 32 years respectively. The estimates of asymptotic length (L∞) and the growth coefficient (K) of Russian sturgeon were 180.95 cm and 0.07 per year respectively. Ship sturgeon had an asymptotic length of 190.67 cm and a growth coefficient of 0.15 per year. The total mortality coefficient (Z) for Russian sturgeon and ship sturgeon were estimated to be 1.14 and 0.79 per year respectively. Annual mortality rates were calculated at 68 percent for Russian sturgeon and 55 percent for ship sturgeon. This study revealed high mortality, low survive rate of studied species that is due to fishing pressure and degradation of environmental conditions. The knowledge of life history of Russian sturgeon and the ship sturgeon in the Iranian Waters of the Caspian Sea have implication in management of the sympatric Russian sturgeon and the ship sturgeon stocks.
Stefano Valdesalici and José Ramón García Gil: Laimosemion mabura, a new killifish from the Essequibo River drainage, Guyana (Cyprinodontiformes: Rivulidae), pp. 166-171
Laimosemion mabura, new species, is described from a small stream belonging to the Essequibo River drainage, central Guyana. Males of Laimosemion mabura are similar to those of L. dibaphus, to which the new species may be closely related, in possessing bluish black pigmentation on the caudal peduncle, but differ in certain morphological characters and elements of colour pattern. The new species belongs to the L. geayi species group, and is distinguished from other members of this assemblage by male colour pattern.
Dalton Tavares Bressane Nielsen and Didier Pillet: Austrolebias accorsii, a new annual fish (Cyprinodontiformes: Rivulidae: Cynolebiatinae) from the upper río Grande basin, Amazon basin, Bolivia, pp. 172-179
Austrolebias accorsii new species is described from Bolivia, departamento de Santa Cruz, Rio Grande, upper Mamoré basin. This is the first record of the genus Austrolebias at the Amazon basin. Austrolebias accorsii new species is distinguished from other members of the Austrolebias bellottii species group by the following combination of characters: absence of dots or spots on body and fins (vs. presence), absence of bars on body (vs. presence), anal-fin origin between neural spines (13th-14th vs. 5th-11th) in males. Austrolebias accorsii females differ from females of other species of the Austrolebias bellottii species group by the combination of a higher number of anal-fin rays (31-32 vs. 23-30), colour pattern of the sides of body light yellowish brown, without bars; usually 1-3 black spots on anterocentral portion of flanks, surrounded by metallic green spots, black spots of random size and quantity on the posterior portion of the body to the caudal peduncle (vs. with bars, one to sixteen black spots on anterocentral portion of flanks without metallic green spots, absent black spots in peduncle caudal).
Dalton Tavares Bressane Nielsen and Didier Pillet: Spectrolebias bellidoi, a new annual fish (Cyprinodontiformes: Rivulidae: Cynolebiatinae) from the upper Río Grande basin, Amazon basin, Bolivia, pp. 180-187
Spectrolebias bellidoi n. sp. is described from a temporary pool from the upper Río Grande, Río Mamoré basin, Departamento Santa Cruz, Bolivia. The new species is distinguished from all congeners by the unique shape of the female’s anal fin, which is composed of two parts, a rounded anterior area, and a posterior portion (from the 14th-15th rays onwards), gradually decreasing in size (vs. entire anal fin with a rounded outline) and a higher number of analfin rays (30 vs. 21-28), in females. It can be additionally distinguished from all congeners, with the exception of S. reticulatus and S. pilleti, by the position of the dorsal fin, which has its origin anterior to the origin of the anal fin in males.
Book review: The freshwater fishes of Suriname by Jan H. A. Mol, pp. 188-189
|Dimensions||26.6 × 20.3 × 0.3 cm|