Using bone measurements to estimate the original sizes of bluefish (Pomatomus saltatrix) from digested remains

The ability to estimate the original size of an ingested prey item is an important step in understanding the community and population structure of piscivorous predators (Scharf et al., 1998). More specifically, knowledge of original prey size is essential for deriving important biological information, such as predator consumption rates, biomass of the prey consumed, and selectivity of a predator towards a specific size class of prey (Hansel et al., 1988; Scharf et al., 1997; Radke et al., 2000). To accurately assess the overall “top-down” pressure a predator may exert on prey community structure, prey size is crucial. However, such information is often difficult to collect in the field (Trippel and Beamish, 1987). Stomach-content analyses are the most common methods for examining the diets of piscivorous fish, but the prey items found are often thoroughly digested and sometimes unidentifiable. As a result, obtaining a direct measurement of prey items is frequently impossible.

Modern dinoflagellate cysts found in surface sediments of Santa Cruz Island, Galapagos

Modern dinoflagellate cysts in surface sediments collected on Santa Cruz Island, Galapagos, are described, along with other palynomorphs such as microforaminiferal linings, tintinnid loricae, copepod eggs and acritarchs including Domasiella-like micro-remains and Halodinium spp. The dinoflagellate cyst assemblages mainly consisted of Spiniferites cf. scabratus (gonyaulacoid) followed by Brigantedinium spp. and Selenopemphix quanta (peridinioids). No gymnodinioid cysts were found. No remarkable differences in cyst composition and densities were recognized between stations. The cyst assemblages were characterized by low species diversity and low cyst concentrations in comparison with the Pacific coast of Guatemala and Peru. CDF Contribution Number 1019.

Anchorage of air bladder with the interspinous bone of the anal fin in Lactarius lactarius (Bloch and Schneider, 1801)

Specimens of the false trevally (Lactarius lactarius ), 127 to 221 mm in total length, were studied for the mode of anchorage of the air-bladder with the interspinous bone of the anal fin. The 1st and 2nd interspinous bones are fused together into a single piece (named here as the anchor bone) which pierces through the air-bladder, dividing it into two intercommunicating chambers at its upper end, and ultimately articulates with the 10th vertebral bone. The lower end of the bone is broad, fan like with one side affording articulation with the 1st and 2nd anal spines. This is an unique feature of great taxonomical importance to L. lactarius, the only species in the family Lactariidae. The anal fin counts (23-27) and vertebral counts (23) are also given.

Successful inoculation of Artemia and production of cysts in the coastal saltpans of Bangladesh II

Bangladesh has no naturally occurring Artemia, and all the growing shrimp hatcheries of the country depend entirely on import of cysts from foreign countries. Following successful inoculation of Artemia and production of cysts for the first time in this country in a coastal saltpan (at Chanua, Banskhali) by the senior author (in 1989-90), a similar second attempt was made under this programme in a saltpan (1000 m super(2)) of Demoshia, Chakaria, Cox's Bazar, Bangladesh between January and April 1992. A total of 1639.9 g (dry weight) of cysts (i.e. 5.46 kg DW/ha/month) have been produced using the Red Jungle Brand, whereas the previous attempt obtained 517 g of cysts (i.e. 2.07 kg DW/ha/month) using the Great Salt Lake Brand.

Effect of decapsulation on viability and hatching performance of Artemia cysts at different salinity levels

Artemia cysts were produced from the traditional solar salt works of Bangladesh through different fertilization treatments were tested for viability and hatching performance in different forms, such as processed and preserved, processed and decapsulated and unprocessed and undecapsulated. Decapsulated cysts performed maximum hatching (86.0%) in 20ppt salinity during 48 hours of incubation. The hatching percentage by the unprocessed and undecapsulated cysts were very low (12.0- 18.7%) in all the tested salinity grades.

Effects of culture treatments on HUFA levels in Artemia cysts

Artemia cysts (of GSL, Utah, USA origin) were produced from the modified traditional solar salt works of Bangladesh during winter months through different feeding/fertilization treatments (T1, T2, T3, T4 ) were analyzed to understand the effects of treatments on their fatty acid profile. Palmitic, Linolenic, Eicosapantaenonic and Docohexaenoic acids (mg/g. DW) were found highest for the cysts in T1 (16.0% ±1 .36), T2 (14.7% ±0.47), T3 (4.7% ±0.40) and T4 (0.7% ±0.06) treatments, respectively. High amount of 18:3(n-3) acids in the cysts of all sources proves to be freshwater type of the cysts. The presence of marine type essential fatty acids in the cysts of all sources were found low for 20:5n-3 (3.7-4.7%) and very low for 22:6n-3 (0.09-0.7%). No significant variation was observed for 16:0 acids within the treatments, but for 18:3(n-3) acid, the variation was found highly significant (P= 0.0052) between T2 and T4 treatments. For 20:5(n-3), only variation between T2 and T4 was found insignificant (P=0.1161), but between other treatments, significant variation was observed between T2 and T4 (P=0.0241), T2 and T4 (P=0.0022) and T1 andT4 (P=0.0161). No significant variation was found in other treatments.

Effects of dietary phosphorus and zinc levels on growth artd bone mineralization in fingerlings of rainbow trout, Oncorhynchus mykiss

A laboratory based 2 x 2 factorial experiment was conducted to investigate the influences of dietary phosphorus and zinc levels on growth and bone mineralization in fingerlings of rainbow trout for 21 weeks. Two levels of phosphorus (19 and 30 mg/g) and two levels of zinc (55 and 103 Ag/g) in the dry diets were tested. Duplicate tanks of 30 rainbow trout (average weight 1.56 ± 0.24 g) per 60L glass tank were fed experimental diets three times a day to apparent satiation level at 15 to 24°C water temperature. The results of the present study demonstrated that dietary phosphorus supplementation influenced the growth and bone mineralization whereas zinc levels significantly (p<0.05) influenced bone mineralization in rainbow trout. Further investigations in this area with different size and age groups of this fish are broadly needed.

Successful inoculation of Artemia and production of cysts in man-made salterns in the Philippines

The authors report on inoculation experiments of Artemia nauplii and young adults of the San Francisco Bay strains in earthen fish ponds. The test inoculated proved successful where water salinity ranges from 20 to 32 o/oo during the start of the rainy season in the Philippines.