Comparing the identification of southern California juvenile rockfishes (genus Sebastes spp.) by restriction site analysis of the mitochondrial ND3/ND4 region and by morphological characteristics

Rockfish (Sebastes spp.) juveniles are often difficult to identify by using morphological characters. This study independently applies morphological characters and a key based on mitochondrial restriction site variation to identify juvenile rockf ishes collected in southern California during juvenile rockfish surveys. Twenty-four specimens of Sebastes were examined genetically without knowledge of the morphological assignment. Seventeen fish were identified genetically as S. semicinctus, S. goodei, S. auriculatus, S. jordani, S. levis, S. rastrelliger, and S. saxicola. Identities for the remaining fish were narrowed to two or three species: 1) three fish were either S. carnatus or S. chrysomelas; 2) one fish was either S. chlorosticus, S. eos, or S. rosenblatti; and 3) three fish could have been either S. hopkinsi or S. ovalis, the latter for which we now have distinguishing mitochondrial markers. The genetic and morphological assignments concurred except for the identity of one fish that could only be narrowed down to S. hopkinsi or S. semicinctus by using morphological characters. Genetics excluded more species from multispecies groupings than did the morphological approach, especially species within the subgenus Sebastomus. Species in the genetically unresolvable groups may be similar because of recent divergence or because of interspecies introgression.

Determining the role of linear and nonlinear interactions in records of climate change: possible solar influences in annual to century-scale records

Time series analysis methods have traditionally helped in identifying the role of various forcing mechanisms in influencing climate change. A challenge to understanding decadal and century-scale climate change has been that the linkages between climate changes and potential forcing mechanisms such as solar variability are often uncertain. However, most studies have focused on the role of climate forcing and climate response within a strictly linear framework. Nonlinear time series analysis procedures provide the opportunity to analyze the role of climate forcing and climate responses between different time scales of climate change. An example is provided by the possible nonlinear response of paleo-ENSO-scale climate changes as identified from coral records to forcing by the solar cycle at longer time scales.

Preparation of prawn pickle and its storage characteristics

Prawn pickle was produced using smaller variety of prawn. Vinegar and salt was used to preserve the prawn muscle against spoilage. Different spices were used to get desired attractive flavour. Benzoic acid to the extent of 200 ppm was used as preservative. Several trials were carried out using different amounts of spices and different methods of preparation. After each trial the sample was subjected to sensory evaluation by judges consisting of five members who had previous experience of acting as panel members. Several trials were carried out to arrive at a final recipe as judged best by the taste panel. Utilizing this final recipe, a product was prepared and subjected to biochemical, bacteriological and organoleptic evaluation and found to be quite acceptable after seven months of storage in glass jar at ambient temperature. The product was subjected to large scale consumer acceptance trial involving 140 consumers, 42% of them ranked it excellent, 41% rated very good, 12% rated good while 5% of the consumers rated it as average.

Preparation of an extruded fish snack using twin screw extruder and the storage characteristics of the product

A value-added extruded fish product was prepared with corn flour (80%) and fish (sciaenid) powder (20%), using a twin-screw extruder. The effect of different parameters like moisture, temperature, fish powder concentration, speed of the extruder and die-diameter on expansion ratio and crisp texture were studied. The storage characteristics of the final product were studied using three different types of packaging under nitrogen flushing. The study revealed that aluminum foil is the best packaging material to keep the product acceptable for more than three months.

Development of intermediate moisture marinated fish product and its storage characteristics

An attempt was made to prepare an intermediate moisture (around 44% moisture) marinated (pH around 4) fish product. Fillets from Sciaenid fish (each fish weighing 70-80 gm) were dipped in a solution containing 7% acetic acid, 20% common salt and 1% propionic acid for 2 hours. After soaking, the soaked fillets were partially dried to about 44% moisture. Three effective hurdles like low pH (by using 7% acetic add and 1% propionic acid), low water activity (by using 20% salt and partially drying the fillets) and preservative (1% propionic add), were used to prepare a shelf-stable product at room temperature. The dried product was sprayed with 0.0 5% BHA in 50% alcohol and further dried for 10 minutes to remove added water and alcohol, thereby another hurdle (preservative) against fat oxidation. The product was packed in 300 gauge polythene bags and stored in transparent screw cap plastic jars. Fortnightly samples were drawn and subjected to biochemical, bacteriological and organoleptic evaluation to study its storage characteristics. The product was in good acceptable form up to 4 months at ambient temperature. The product needed one hour soaking in water with two changes of water in between to make it free from excess salt and acid smell.

Iced and frozen storage characteristics of cultured Chanos chanos (Forskal)

Freshly harvested milk fish (Chanos chanos) were stored in crushed ice and their storage life estimated by following biochemical, bacteriological and organoleptic changes occurring during storage. Samples of the fish were withdrawn at various intervals of storage, quick frozen, glazed and held in frozen storage at-l8°C. Shelf-life in frozen storage was determined in relation to period of ice storage prior to freezing by determining biochemical and organoleptic characteristics up to 30 weeks.

Some observations on the growth and cyst production characteristics of the brine shrimp Artemia sp. (Gujarat strain) in pond culture and its potential for import substitution

Experimental culture of the brine shrimp Artemia sp. (Gujarat strain) and production of cyst is discussed. The qualitative and quantitative aspects of the cyst and its economic potential for import substitution are highlighted.