Enterolith with a stingray spine nidus in an Atlantic bottlenose dolphin (Tursiops truncatus)

In March 2006, a dead, male bottlenose dolphin (Tursiops truncatus) was found in the salt marsh in Charleston, South Carolina, United States. During necropsy, an enterolith was found completely obstructing the intestinal lumen. Further examination of the enterolith revealed a stingray spine nidus. Most terrestrial enteroliths are composed primarily of struvite (magnesium ammonium phosphate); however, the majority of the enterolith discovered in the stranded dolphin was composed of calcium phosphate carbonate. This case provides an interesting comparison of the variation in the mineral composition between terrestrial and marine enteroliths.

Ascorbic acid turnover in the ocular tissues of some fishes

The ascorbic acid turnover from the ocular tissues of 11 species of fishes from a culture pond and the river Godavari (Andhra Pradesh, India) has been studied. The free ascorbic acid and ascorbigen contents were more in the case of bottom or deep dwelling fishes and the least in the case of surface living forms, depending upon the light penetration in the area that each species inhabits. The enzymic utilization and ascorbic acid-macromolecule complex varied among the fishes possibly depending upon individual energy requirements and not upon light intensity. No size-related or sex-related variation was observed. No variation was observed between riverine and pond-reared fishes of the same species.

Manipulation of chromosomes in fish: review of various techniques and their implications in aquaculture

Human ingenuity has made it possible to advent the chromosome manipulation techniques to produce individuals with differing genomic status in a number of fish using various causal agents such as physical shocks (temperature or hydrostatic pressure), chemical (endomitotics) and anesthetic treatments either to suppress the second meiotic division shortly after fertilization of eggs or to prevent the first mitotic division shortly prior to mitotic cleavage formation. This results in the induction of polyploidy (triploidy and tetraploidy), gynogenesis (both meiotic and mitotic leading to clonal lines) and androgenesis in fish population. The rationale for the induction of such ploidy in fish has been its potential for generating sterile individuals, rapidly inbred lines and masculinized fish, which could be of benefit to fish farming and aquaculture. In this paper, these are critically reviewed and the implication of recently developed chromosome manipulation techniques to various fin fishes is discussed.

Investigation on bacterial flora of farmed freshwater prawn (Macrobrachium rosenbergii de Man) in Bangladesh

Total bacterial load in the haemolymph of freshwater prawn Macrobrachium rosenbergii varied from 6.2x10⁴ to 1.9x10⁷ CFU/ml whereas in the hepatopancreas, bacterial load varied from 1.9x10³ to 2.9x10⁵ CFU/g. The total bacterial load in the pond water varied from 2.6x10² to 4.1x10⁵ CFU/ml. The isolated bacterial genera in the haemolymph and the hepatopancreas of prawn were Streptococcus, Acinetobacter, Micrococcus, Aeromonas, Vibrio, Flavobacterium, Staphylococcus and Pseudomonas, whereas the detected bacterial genera in pond water were Micrococcus, Streptococcus, Vibrio, Flavobacterium, Staphylococcus, Pseudomonas and Aeromonas. Among the detected genera, Vibrio and Staphylococcus were found to be dominant genera in the haemolymph of the sampled prawn throughout the study period whereas Staphylococcus and Pseudomonas were dominant in pond water.

Preservation of fish by freezing and glazing. Pt. 3. Effect of freezing, glazing and frozen storage on the B-vitamins and essential minerals present in the fish flesh

The changes occurring in moisture, thiamine, riboflavin niacin, phosphorus, iron and calcium in pomfret, surmai and frozen mackerel, glazed with ascorbic acid, citric acid, sodium chloride, glucose, sodium nitrite and kept under frozen storage were studied up to 6 months and results reported.

Algorithm for identification in the v-gap metric

This paper suggests a method for identification in the v-gap metric. For a finite number of frequency response samples, a problem for identification in the v-gap metric is formulated and an approximate solution is described. It uses an iterative technique for obtaining an L2-gap approximation. Each stage of the iteration involves solving an LMI optimisation. Given a known stabilising controller and the L2-gap approximation, it is shown how to derive a v-gap approximation.

Fluctuations in species composition of Penaeid prawns in estuaries

During a study of the distribution of penaeid prawns in Sri Lanka waters a difference was noticed in the species composition from one estuary to another. Moreover, a marked monthly fluctuation in the relative abundance of the different penaied species was also observed. This indicated migratory behaviour. In order to study this phenomenon in the different species of prawns, regular samples of prawns were collected from two estuaries on the south-west coast of Sri Lanka, namely at Moratuwa/Panadura and at Negombo. The investigation was spread over a period of three years from 1957-1959.

Survey on the quality of Jaadi available [in] Sri Lankan market

A quality of survey was conducted at the fish curing yards in a northwest coast and the southern coast in Sri Lanka. A total of 40 samples different varieties of fishes were collected from the market and jaadi curing yards and all were evaluated for the quality, fungal and insect infestation. Samples were analyzed for proximate composition chemical, microbiological and sensory quality. Thirty percent of the total analyzed samples of fish were found to be unfit for consumption. Samples collected from Negombo were found to the infected with maggots. Only 42% samples had dry matter above 50%. All the samples showed a protein content above 20%. The highest protein content was 27.92% in hurulla. Over 90% of the samples had TVN at acceptable quality limits (>40). The TBC for 33% of the samples were in the range 104-105/g range, while 48% were in the range of 107-108/g due to contamination of maggots and fungi. The Survey showed jaadi had a high level of protein in its composition. But defects of curing process such on imperfect cleaning inadequate salting resulted in low (Chemical and microbiological) quality of the product.

Prevalence of ectoparasites in farmed Pangasius hypothalamus

Of the total 240 Pangasius hypothalamus (5 - 8.7cm) fry examined during September' O1 to February'02, 80 (33.33%) were found to be infested with one or more ecroparasites irrespective of genera or groups. Seven parasitic groups were identified with the highest average prevalence of Trichodinids (55%) followed by Dacrylogyrus spp. ( 42%), Episrylis spp. (8%), Apiosoma spp. (7%) Argulus spp. (5%), Gyrodacrylus spp. (4%) and Piscicola spp. (2%) the lowest prevalent group irrespective of months. Trichodinid and Dacrylogyms spp. were recorded to be the dominating parasitic groups among the seven both in terms of monthly prevalence and severity of infestation throughout the period of investigation. The highest prevalence (60%) of ectoparasite was recorded in December and the lowest (10%) in February irrespective of groups.

Effect of sublethal concentration of artificial seawater on oxygen uptake and opercular frequency in an Indian major carp, Labeo rohita (Ham.)

The present study reports the effect of artificial seawater on oxygen uptake and opercular frequency in an Indian major carp, Labeo rohita. Whereas a control fish of 7.34 g average body weight consumed 1.538 ml O sub(2.) hˉ¹, the 24h and 96h exposed fish of the same body weight consumed 1.07 4 and 0.897 ml O sub(2.) hˉ¹, respectively. The oxygen uptake per unit body weight under controlled condition was 0.219 ml. g��¹. hˉ¹, whereas in 24h and 96h exposed fish, it was 0.152 and 0.124 ml. g��¹, hˉ¹, respectively. The change in opercular movement in 24h exposed fish was 7.67% higher, whereas in 96h exposed fish, it was 22.43% higher as compared to the control one. All changes are highly significant (p<0.001).

Fishing gear in freshwater reservoirs of India

Consequent on the great emphasis given to irrigation, power generation and flood control, several river valley reservoirs have been formed. The fact that these reservoirs support a fairly rich fishery potential needs no special mention. The total reservoir water area in the country is 6.4 lakh h.a. (16 lakh acres) and the yield is 5 to 8 kgm/h. a. in certain reservoirs, rising up to 40 kgm/h.a. in some of the highly productive ones.