Length-weight Relationships of Four Commercially Important Fish Species in Indonesia

Length-frequencies and length-weight relationships of the four economically important fish species Encrasicholina heteroloba (Rüppel 1837), E. punctifer Fowler 1938, Katsuwonus pelamis (Linnaeus 1758) and Rastrelliger kanagurta (Cuvier 1816) were analysed to assess the condition of the respective stocks. Length-frequency data were analysed to estimate the theoretical maximum size of fish in a stock (L∞) and the coefficient K, indicating how fast fish reach that size. A power model approach was used with length and weight data to estimate the condition factor a and allometry coefficient b. The two anchovy species (Encrasicholina) showed similar values with = 9.45 cm, K = 1.10 year-1, a = 0.00672 and b = 2.919 for E. heteroloba and L∞ = 10.78 cm, K = 1.00 year-1, a = 0.01031 and b = 2.871 for E. punctifer. For both species, the allometry coefficient was below 3, implying allometric growth. The estimated parameters for the skipjack tuna K. pelamis and the Indian mackerel R. kanagurta were L∞= 72.32 cm, K = 0.38, a = 0.0395 and b = 2.766 and L∞= 27.83 cm, K = 0.92, a = 0.00556 and b = 3.216, respectively. All data were collected in Pasir Kendang, Padang, West-Sumatra in 1993 and 1994.

Characterization of acid-and pepsin-soluble collagens from spines and skulls of skipjack tuna (Katsuwonus pelamis) / 中国天然药物

Acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) from the spine (ASC-SP and PSC-SP) and skull (ASC-SK and PSC-SK) of the skipjack tuna, Katsuwonus pelamis, were successfully isolated and characterized. The yields of ASC-SP, PSC-SP, ASC-SK and PSC-SK were (2.47 ± 0.39)%, (5.62 ± 0.82)%, (3.57 ± 0.40)%, and (6.71 ± 0.81)%, respectively, on the basis of dry weight. The four collagens contained Gly (330.2-339.1 residues/1 000 residues) as the major amino acid, and their imino acid contents were between 168.8 and 178.2 residues/1 000 residues. Amino acid composition, SDS-PAGE, and FTIR investigations confirmed that ASC-SP and ASC-SK were mainly composed of type I collagen, and had higher contents of high-molecular weight cross-links than those of PSC-SK and PSC-SP. The FTIR investigation also certified all the collagens had triple helical structure. The denaturation temperatures of ASC-SK, PSC-SK, ASC-SP, and PSC-SP were 17.8, 16.6, 17.6, and 16.5 °C, respectively. All isolated collagens were soluble at acidic pH (1-5) and lost their solubilities when the NaCl concentration was above 2% (W/V). The isolated collagens from the spines and skulls of skipjack tuna could serve as an alternative source of collagens for further application in food, cosmetic, biomedical, and pharmaceutical industries.

Distribución y abundancia de larvas del pez Katsuwonus pelamis (Perciformes: Scombridae) en el Golfo de México, 1982-1992

Distribution and abundance of Katsuwonus pelamis larvae (Perciformes: Scombridae) in the Gulf of Mexico, 1982-1992. The epipelagic fish known as skipjack (Katsuwonus pelamis) is considered inside the "little tuna" group. The species is distributed in tropical and subtropical waters worldwide. Despite its fisheries importance in Mexico, there is little knowledge about the species in the region. The information from 18 oceanographic cruises inside the Mexican exclusive economic zone in the Gulf of Mexico and Caribbean Sea, was analyzed for the period 1982 to 1992. Plankton was collected in a paired 60 cm mouth bongo net sampler with 0.333 mm mesh nets in oblique tows. The maximum abundance was in spring and summer; 1986 had the largest population (4 881.8544 x 10(9) larvae) and 1983 the lowest density (566.3748 x 10(9)). The skipjack has suitable conditions for reproduction in this area, and the southwestern region is the most productive. The spawning was greater in the summer. The annual biomass was estimated in 2 513 to 21 659 tons, the high value corresponded to 1986, with potential yields between 7 472 and 10 071 tons. A local fishery seems viable but needs further evidence. Rev. Biol. Trop. 56 (3): 1343-1359. Epub 2008 September 30.

El barrilete Katsuwonus pelamis, considerado en el grupo de los atunes menores, es una especie epipelágica, distribuida en aguas tropicales y subtropicales del mundo, que ha llegado a convertirse en uno de los atunes más capturados. Sin embargo, en México se han realizado pocos estudios a pesar de su importancia en esta región. Analicé la información recolectada en 18 cruceros oceanográficos en la zona económica exclusiva mexicana del Golfo de México y Mar Caribe (1982 a 1992). Las muestras se obtuvieron mediante arrastres oblicuos de redes tipo bongo de 60 cm de boca y malla de 0.333 mm. Las máximas abundancias de larvas se presentaron en primavera y verano, y 1986 se caracterizó por tener una mayor población, un total de 4 881.8544 x 10(9) larvas, 1983 tuvo la más baja densidad con 566.3748 x 10(9). El barrilete se encontraba entonces en las condiciones adecuadas para su reproducción en esta área, siendo la región sudoccidental la más productiva; el desove fue mayor en verano. Las biomasas calculadas por temporada fueron de 2 513 a 21 659 toneladas, correspondiendo a 1986 el valor más alto, con un rendimiento potencial entre 7 472 y 10 071 t. Es factible explotarlo en el Golfo de México si otra información corrobora estos resultados.