Identification of the egg, early life history and spawning areas if the anchoveta, Cetengraulis mysticetus (Günther), in the Gulf of Panama

ENGLISH: The egg of the anchoveta, Cetengraulis mysticetus (Günther), was identified in the Gulf of Panama by its size, difference in diurnal period of spawning, seasonal occurrence (October to January) and relative abundance. It is pelagic, translucent and oval with mean dimensions of 1.166 mm. and 0.558 mm. for the long and short axes respectively. The egg membrane is unsculptured, the yolk mass is markedly segmented, and no oil globule or pigmentation is present. It was not found in the plankton from mid-January 1957 until the latter part of the following September; during this period the gonads of the anchoveta were immature. Only one other anchovy egg, spawned during the same diurnal period, is sufficiently similar in dimensions to be confused with that of the anchoveta; however, it is slightly smaller. SPANISH: El huevo de la anchoveta, Cetengraulis mysticetus (Günther), fué identificado en el Golfo de Panamá por su tamaño, diferencias en el período diario de desove, su abundancia en la temporada (de octubre a enero) y por su abundancia relativa. El huevo es pelágico, translúcido, oval y con dimensiones promedio de 1.166 mm. y 0.558 mm. para los ejes largo y corto, respectivamente. La membrana es lisa, el vitelo está francamente segmentado y no posee ningún glóbulo graso o pigmentación. El huevo de la anchoveta no se encontró en el plancton en el período comprendido entre mediados de enero y fines de septiembre de 1957; durante este lapso las gónadas estuvieron inactivas.

The effects of dieldrin on various life stages of the African catfish Clarias gariepinus (Burchell)

Early life stages (ELS) of Clarias gariepinus were found to be less sensitive to acute dieldrin toxicity than ELS of Nile tilapia, Oreochromis niloticus; 96 h LC50 for 37 day old fry were 11.7 and 4.95pg/l, respectively. Growth of O. niloticus fry was significantly reduced in 22.4 pg/l dieldrin whereas growth of C. gariepinus fry was unaffected. Adult C. gariepinus rapidly absorbed dieldrin from aquaeous solution and accumulated it in their tissues, especially in the liver where after 30 days in 4.0 pg/l bioconcentration was close to 1000 fold. Chronic exposure of C. gariepinus to dieldrin had no effect on blood haematocrit and haemoglobin, but appeared to slow the growth of catfish, and had a clear negative effect on the reproductive potential of mature females

Determination of proximate composition, shelf life and fatty acid profiles of breaded kilka (Clupeonella cultriventris) during frozen storage

The present study aimed production of a new product with various texture and sensory properties in chase of the impetus for increasing human consumption considering suitable resources of Kilka fish in Caspian Sea. Following deheading, gutting, and brining, common Kilka were battered in two different formulations, i.e. simple batter and tempura batter, via automated predusting machinery and then, they were fried through flash frying for 30 seconds at 170°C in sunflower oil after they were breaded with bread crumbs flour. The products were subjected to continuous freezing at -40°C and were kept at -18°C in cold storage for four months once they were packed. Chemical composition (protein, fat, moisture, and ash), fatty acid profiles (29 fatty acids), chemical indices of spoilage (peroxide value, thiobarbituric acid, free fatty acids, and volatile nitrogen), and microbial properties (total bacteria count and coliform count) were compared in fresh and breaded Kilka at various times before frying (raw breaded Kilka), after frying (zero-phase), and in various months of frozen storage (phases 1, 2, 3, and 4). Organoleptic properties of breaded Kilka (i.e. odor, taste, texture, crispiness, cohesiveness of batter) and general acceptability in the phases 0, 1, 2, 3, and 4 were evaluated. The results obtained from chemical composition and fatty acid profiles in common Kilka denoted that MUFA, PUFA, and SFA were estimated to be 36.96, 32.85, and 29.12 g / 100g lipid, respectively. Levels of ù-3 and ù-6 were 7.6 and 1.12 g / 100 gr lipid, respectively. Docosahexaonoic acid (20.79%) was the highest fatty acid in PUFA group. ù-3/ù-6 and PUFA/SFA ratios were 7.6 and 1.12, respectively. The high rates of the indices and high percentage of ù-3 fatty acid in common Kilka showed that the fish can be considered as invaluable nutritional and fishery resources and commonsensical consumption of the species may reduce the risk of cardiovascular diseases. Frying breaded Kilka affected overall fat and moisture contents so that moisture content in fried breaded Kilka decreased significantly compared to raw breaded Kilka, while it was absolutely reverse for fat content. Overall fat content in tempura batter treatment was significantly lower than that of simple batter treatment (P≤0.05). Presence of hydrocolloids, namely proteins, starch, gum, and other polysaccharides, in tempura batter may prohibit moisture evaporation and placement with oil during frying process in addition to boosting water holding capacity through confining water molecules. During frying process, fatty acids composition of breaded Kilka with various batters changed so that rates of some fatty acids such as Palmitic acid (C16:0), Stearic acid (C18:0), Oleic acid (C18:1 ù-9cis), and linoleic acid (C18:3 ù-3) increased considerably following frying; however, ù-3/ù-6, PUFA/SFA, and EPA+DHA/C16:0 ratios (Polyan index) decreased significantly after frying. ù-3/ù-6, PUFA/SFA, and EPA+DHA/C16:0 ratios in tempura batter treatment were higher than those of simple batter treatment which is an indicator of higher nutritional value of breaded Kilka with tempura batter. Significant elevations were found in peroxide, thiobarbituric acid, and free fatty acids in fried breaded Kilka samples compared to raw samples which points to fat oxidation during cooking process. Overall microorganism count and coliform count decreased following heating process. Both breaded Kilka samples were of high sanitation quality at zero-phase according to ICMSF Standard. The results acquired from organoleptic evaluation declared that odor, cohesiveness, and general acceptability indices, among others, had significant differences between the treatments (P≤0.05). In all evaluated properties, breaded Kilka with tempura batter in different phases gained higher scores than breaded Kilka with simple batter. During cold storage of various treatments of breaded Kilka, total lipid content, PUFA, MUFA, ù-3, ù- 3/ù-6, PUFA/SFA, Polyen index decreased significantly. The mentioned reductions in addition to significant elevation of spoilage indices, namely peroxide, thiobarbituric acid, and free fatty acids, during frozen storage, indicate to oxidation and enzymatic mechanism activity during frozen storage of breaded Kilka. Considering sensory evaluation at the end of the fourth month and TVB-N contents exceeded eligible rate in the fourth month, shelf life of the products during frozen storage was set to be three months at -18°C. The results obtained from statistical tests indicate to better quality of breaded Kilka processed with tempura batter compared to simple batter in terms of organoleptic evaluation, spoilage indices, and high quality of fat in various sampling phases.