Ultrastructural alterations in the gills of cyprinid,<i> Labeo rohita</i> (Hamilton) exposed to Lead nitrate

570-575Lead contaminates aquatic ecosystems and causes deleterious effects on aquatic organisms, particularly fishes, and percolates to human beings through food chain as accumulated residue. In this context, we conducted histological studies on impact of lead toxicity in Rohu, Labeo rohita (Hamilton), a common freshwater fish consumed by humans, exposed to sub-lethal concentrations of lead nitrate. Previously, we observed damage in the gills using light microscope, and now we studied ultrastructural alterations at cellular level in the gills using Transmission electron microscopy (TEM). The gill tissues were dissected after 15, 30, 45 and 60 days of exposure, washed, fixed in Karnovsky's fixative, and processed further for histological investigation. Normal cellular architecture was noticed in the control group while, whereas large number of alterations could be observed in different organelles in the cells of the lead nitrate treated groups. The severity of the lesions was proportional to the increased concentration of the tested pollutant in a time dependent manner

Comparative studies on age and growth patterns of cultivated and wild Catla catla (Hamilton)

144-149Catla catla (Hamilton) is one of the fastest growing Indian major carps (IMCs) with increasing market demand. Consistent demand and exploitation invites the attention of ichthyologists for its conservation strategies. Age and growth studies play a pivotal role for managing the fishery stocks in different water bodies. Here, we studied the age and growth patterns using opercula of both farm grown as well as the wild grown C. catla adopting standard methodologies. Wild specimens were caught from Harike wetland (Ramsar site) and the cultivated one from a farm at Dhudike in Punjab. High value of correlation coefficient ‘r’ 0.976 (wetland) and 0.983 (farm) reveals the strong relationship in total length and operculum radius of the fish. C. catla achieved average total length from wetland and farm, respectively at 1st (273.44 mm) 2nd (427.44 mm) 3rd (525.49 mm) 4th (624.52 mm) 5th (744.98 mm) 6th (813.62 mm) and 1st (282.1 mm) 2nd (463 mm) 3rd (601.7 mm) year of age of opercular bones study. The growth parameters such as, index of species average size (φh) 135.6 (wetland) and 200.6 (farm), growth constant (Clt) showed two growth phases from both localities i.e. sexual immaturity up to 2 years and sexual maturity afterwards. Whereas, growth characteristic (Cth) has revealed irregular growth pattern at wetland in comparison to growth of fish from farm. The results of this study concluded that the fish experienced more growth from the farm due to better and controlled conditions but, in wetland surrounding conditions were observed to be unfavourable for survival of the fish C. catla

Ultrastructural alterations in the gills of cyprinid, Labeo rohita (Hamilton) exposed to Lead nitrate

Lead contaminates aquatic ecosystems and causes deleterious effects on aquatic organisms, particularly fishes, and percolates to human beings through food chain as accumulated residue. In this context, we conducted histological studies on impact of lead toxicity in Rohu, Labeo rohita (Hamilton), a common freshwater fish consumed by humans, exposed to sub-lethal concentrations of lead nitrate. Previously, we observed damage in the gills using light microscope, and now we studied ultrastructural alterations at cellular level in the gills using Transmission electron microscopy (TEM). The gill tissues were dissected after 15, 30, 45 and 60 days of exposure, washed, fixed in Karnovsky's fixative, and processed further for histological investigation. Normal cellular architecture was noticed in the control group while, whereas large number of alterations could be observed in different organelles in the cells of the lead nitrate treated groups. The severity of the lesions was proportional to the increased concentration of the tested pollutant in a time dependent manner

Comparative studies on age and growth patterns of cultivated and wild Catla catla (Hamilton)

Catla catla (Hamilton) is one of the fastest growing Indian major carps (IMCs) with increasing market demand. Consistent demand and exploitation invites the attention of ichthyologists for its conservation strategies. Age and growth studies play a pivotal role for managing the fishery stocks in different water bodies. Here, we studied the age and growth patterns using opercula of both farm grown as well as the wild grown C. catla adopting standard methodologies. Wild specimens were caught from Harike wetland (Ramsar site) and the cultivated one from a farm at Dhudike in Punjab. High value of correlation coefficient ‘r’ 0.976 (wetland) and 0.983 (farm) reveals the strong relationship in total length and operculum radius of the fish. C. catla achieved average total length from wetland and farm, respectively at 1st (273.44 mm) 2nd (427.44 mm) 3rd (525.49 mm) 4th (624.52 mm) 5th (744.98 mm) 6th (813.62 mm) and 1st (282.1 mm) 2nd (463 mm) 3rd (601.7 mm) year of age of opercular bones study. The growth parameters such as, index of species average size (φh) 135.6 (wetland) and 200.6 (farm), growth constant (Clt) showed two growth phases from both localities i.e. sexual immaturity up to 2 years and sexual maturity afterwards. Whereas, growth characteristic (Cth) has revealed irregular growth pattern at wetland in comparison to growth of fish from farm. The results of this study concluded that the fish experienced more growth from the farm due to better and controlled conditions but, in wetland surrounding conditions were observed to be unfavourable for survival of the fish C. catla

Histopathological alterations in the gills of <i>Labeo</i> <i>rohita </i> (Hamilton-Buchanan) due to Lead toxicity

576-583Lead is an industrially important heavy metal used in manufacturing paints, batteries, explosives, pottery and other important products of daily life. On the other hand, it is the most damaging element for aquatic fauna especially fish as it accumulates in the body of organism and have low rate of elimination. The present paper emphasizes on the histopathological effects of different sub-lethal doses of lead nitrate on the gills of a commonly consumed freshwater fish Rohu, Labeo rohita. After 15, 30, 45 and 60 days of exposure, gill tissues were dissected and routine histological processes were done. No changes were seen in the gills of the control fingerlings. The histopathological changes such as cellular hypertrophy, hyperplasia, vacuolation, epithelial lifting, shortening, curling and abnormal elongation of the secondary lamellae, fusion of adjacent lamellae, telangiectasis, blood congestion, interstitial edema, necrosis, lamellar aneurysm, architectural distortion and degeneration of gills were observed in the gills of the treated fingerlings. The extent of damage of gill tissue was proportionate with the increased dosage and duration of lead nitrate exposure