Morphometric measurements as an index for estimating yield of meat in shell fishes, 2. Mussel (Perna viridis) and clam (villorita cyprinoides)

Observations (76 nos) on height-length and whole weight-meat weight relations of mussels (Perna viridis), both wild and cultured were made. From the length of mussel the height can be worked out by the equations (logarithmic scale), 1. y = 0.360+0.988 x for wild; 2. y = 0.334+1.011 x for cultured, where x is the length (cm) and y is the height (cms). So also to any height the corresponding meat weight can be obtained by the regression equation. log w=-0.8178+1.9769 log H for wild variety (1) log w=-1.3049+2.8385 log H for culture-variety (2) where w is the meat weight (g) and H is the height (cm) of the mussel. Fourteen observations on size weight measurements of dams were made. The yield varied from 8.9 to 13%. The length-height relationship worked out for clams (Villorita sp) is y=0.485+1.005 x for length x and height y.

Morphometric measurements as an index for estimating yield of meat of shell fishes, 1. Crab (Scylla serrata) Forskal

Sixty one observations on length-breadth and whole weight-meat weight relations of India crab (Scylla serrata) were made. From the length of crab (cm) the whole weight (gm) can be computed by the equation: log W=-0.1708+2.3341 log L. Similarly for any given length (cm) the meat weight (gm) can be found by the relation, log w=-1.5745+3.0148 log L.

Larval and postlarval development of the window-pane shell, Placuna placenta L. (Bivalvia: Placunidae)

Stages of development of P. placenta from the straight-hinge veliger to the adult are described. Mature larvae metamorphose at lengths from 220-230 m. Larvae probably attach byssally to the water surface at metamorphosis and remain in the plankton for some time before finally settling on the mud bottom.

Effect of chitin and prawn shell on the growth of albino rat

The effect of addition of pure chitin from prawn shell, deproteinised prawn shell, demineralized prawn shell and dry prawn shell in casein based control diet on albino rats was studied. The diets contained 0.5% chitin and 10% protein. The results obtained in the studies show that the weight gain and feed conversion were maximum in the control diet. While addition of pure chitin slightly brought down the weight gain, addition of deproteinsed prawn shell have the minimum weight gain showing that presence of minerals adversely affects both feed consumption and weight gain in the case of albino rats. Although it was reported that addition of pure chitin at 0.5% in the commercial feed of broiler chicken gave increased weight, in the case of albino rats the weight gain was slightly reduced compared to control diet.