Oogenesis and spawn formation in the invasive lionfish, Pterois miles and Pterois volitans

The Indo-Pacific lionfish, Pterois miles and P. volitans, have recently invaded the U.S. east coast and the Caribbean and pose a significant threat to native reef fish communities. Few studies have documented reproduction in pteroines from the Indo-Pacific. This study provides a description of oogenesis and spawn formation in P. miles and P. volitans collected from offshore waters of North Carolina, U.S.A and the Bahamas. Using histological and laboratory observations, we found no differences in reproductive biology between P. miles and P. volitans. These lionfish spawn buoyant eggs that are encased in a hollow mass of mucus produced by specialized secretory cells of the ovarian wall complex. Oocytes develop on highly vascularized peduncles with all oocyte stages present in the ovary of spawning females and the most mature oocytes placed terminally, near the ovarian lumen. Given these ovarian characteristics, these lionfish are asynchronous, indeterminate batch spawners and are thus capable of sustained reproduction throughout the year when conditions are suitable. This mode of reproduction could have contributed to the recent and rapid establishment of these lionfish in the northwestern Atlantic and Caribbean.

Prey consumption of Steller sea lions (Eumetopias jubatus) off Alaska: How much prey do they require?

The effects of seasonal and regional differences in diet composition on the food requirements of Steller sea lions (Eumetopias jubatus) were estimated by using a bioenergetic model. The model considered differences in the energy density of the prey, and differences in digestive efficiency and the heat increment of feeding of different diets. The model predicted that Steller sea lions in southeast Alaska required 45–60% more food per day in early spring (March) than after the breeding season in late summer (August) because of seasonal changes in the energy density of the diets (along with seasonal changes in energy requirements). The southeast Alaska population, at 23,000 (±1660 SD) animals (all ages), consumed an estimated 140,000 (±27,800) t of prey in 1998. In contrast, we estimated that the 51,000 (±3680) animals making up the western Alaska population in the Gulf of Alaska and Aleutian Islands consumed just over twice this amount (303,000 [±57,500] t). In terms of biomass removed in 1998 from Alaskan waters, we estimated that Steller sea lions accounted for about 5% of the natural mortality of gadids (pollock and cod) and up to 75% of the natural mortality of hexagrammids (adult Atka mackerel). These two groups of species were consumed in higher amounts than any other. The predicted average daily food requirement per individual ranged from 16 (±2.8) to 20 (±3.6) kg (all ages combined). Per capita food requirements differed by as much as 24% between regions of Alaska depending on the relative amounts of low–energy-density prey (e.g. gadids) versus high–energy-density prey (e.g. forage fish and salmon) consumed. Estimated requirements were highest in regions where Steller sea lions consumed higher proportions of low–energy-density prey and experienced the highest rates of population decline

Changes in mid-troposphere snow accumulation on Mt. Logan, Yukon, over the last three centuries

EXTRACT (SEE PDF FOR FULL ABSTRACT): A net snow accumulation time series is presented. It is derived from a 102.5 m ice core retrieved from Mt. Logan at an altitude of 5340 m a.s.l. Annual increments are identified using stable isotopes, trace chemistry, and beta activity. ... The resulting time series of nearly 300 years seems to indicate a lower mean accumulation from AD 1700 to the mid-19th century than after that time. The last 100 years of the series correlates significantly with certain instrumental station records at mid-northern latitudes.

Initial global perspective of climate for the last thousand years: the ice core record

Climatic and environmental records from low, middle, and high latitude ice cores greatly increase our knowledge of the course of past events. This historical perspective is essential to predict climatic oscillations, dominated as they may be by increasing greenhouse gas concentrations. Forcing factors, internal and external, that have operated in the past will continue to influence the course of events.

Faecal indicator organisms in frozen prawn products. Pt. 2. Survival of the organisms during freezing and frozen storage

The rate of survival of different types of faecal indicator organisms like Escherichia coli, enterococci etc. during freezing and frozen storage has been studied. Peeled and deveined prawns inoculated with a mixed culture of the above organisms were subjected to freezing and storage at -10̊F and examined for over four months.

Studies on the storage behaviour of laminated and commercial Bombay duck

A modified method for the preparation of laminated Bombay duck is presented. Investigation was carried out to find out an effective chemical to control the discoloration of dried laminated Bombay duck. Among various chemicals tried, NDGA and BHT were found to have considerably retarded the discoloration and extended the storage life of the product. Attempt was also made to suggest the optimum humidity level for the proper storage of the commercially dried fish. It was found that a level of about 65% R. H. provided maximum storage life to commercial product.

Monogenean infestations in Thai silver barb (Barbodes gonionotus Bleeker) and their adaptations in Bangladesh waters

An investigation on the infestation of monogenetic trematodes of Barbodes gonionotus was conducted during the period from July '97 to June '98. Host specimens were collected from local fish farms and also from local fish markets of Mymensingh. Samples of P. ticto and P. sarana were also examined. Two species - Dactylogyrus lampam (Lim and Furtado 1986) and Dactylogyrus siamensis (Chinabut and Lim 1993) the Thai parasites were recorded from B. gonionotus and D. lampam, from our indigenous fish P. sarana. Two species of Gyrodactylus were also recorded from B. gonionotus. Both prevalence and intensity of infestation were moderate in B. gonionotus. Prevalences were recorded higher in larger fishes and mean intensity in intermediate size group fishes. Infestations were higher in winter months. Adaptations of the foreign parasites in Bangladesh waters, their transmission in local fishes and invasion of the local parasites to this exotic fish have been discussed. Suggestions have also been made to protect the introduction of new species in our waters.

Seasonal and sex related haematological variations of the freshwater spiny eel, Mastacembelus armatus reared in the cemented cisterns

The seasonal and sex related haematological vanatlons in the freshwater spiny eel Mastacembelus armatuswere studied during summer from April to June 2001 and winter from November 2001 to January 2002. In total 60 fish (30 males and 30 females) ranging from 30- 55.6 cm in total length and from 55-95.5 g in weight were collected from the culture stock maintained in the cemented cisterns. It was observed that the values of the total erythrocyte count (TEC), haemoglobin concentration (Hb ), haematocrit values, packed cell volume (PCV) and neutrophil count were significantly higher (P< 0.05) in males than the females during summer (April to June- on-set of breeding season). Females were observed to have remarkably higher values (P< 0.01) of erythrocyte sedimentation rate (ESR), total leucocyte count (TLC) and thrombocyte count during summer. On the other hand, insignificant variations in the various haematological parameters were noticed during winter (November to January) between the two sexes of M. armatus.

A brief account on the 'Gunja Net' fishing of the Kutch Backwaters (Gujarat)

A survey was made of the fishing gear (Gunja net) and methods used in the prawn fishery of the coastal waters of the Gulf of Kutch.

Effect of demonstration in transferring fish processing technology

A group of 28 fisherwomen who attended demonstration on three subjects, namely, preparation of fish wafers, fish pickles and fish soup powder showed significant knowledge and skill gain for all the three messages. The total knowledge and skill gain was maximum for preparation of fish wafers followed by that for preparation of fish soup powder and fish pickles.

Status and prospects of mackerel and tuna fishery in Bangladesh

Present status and future prospects of mackerel and tuna fisheries in Bangladesh were assessed during July 2003-June 2004. The work concentrated on the fishing gears, length of fishes, total landings and market price of the catch and highlighted the prospects of the fishery in Bangladesh. Four commercially important species of mackerels and tuna viz. Scomberomorus guttatus, Scomberomorus commerson, Rastrelliger kanagurta, and Euthynnus affinis were included in the study. About 95% of mackerels and tuna were caught by drift gill nets and the rest were caught by long lines (4%) and marine set-bag-net (1%). Average monthly total landing of mackerels and tunas was about 264 t, of which 147 t landed in Cox's Bazar and 117 t in Chittagong sites. Total catches of the four species in Cox's Bazar and Chittagong sites were found to be 956 and 762 t, respectively. The poor landing was observed during January-February and the peak landing was in November and July. Gross market value of the annual landing of mackerels and tunas (1,718 t) was found to be 1,392 latch taka. Nevertheless, the mackerel and tuna fisheries in Bangladesh are increasingly contributing to the marine fish production of the country and have very good potential for further expansion for both domestic and export market.

Study on fish hatchery and nurseries in Mymensingh, Bangladesh

In generally, fish hatchery and nursery owners having both hatchery and nursery facilities were financially stronger, well-educated and well-trained than only nursery ponds owners in Mymensingh aquaculture region. On the other hand, only nursery pond owners were more experienced in fish seed business than only hatchery owners. Most of the owners were satisfied with existing communication facilities. Lack of technical knowledge was one of the major constraints which could be solved by ensuring proper training. This business can be made more profitable providing loan to poor farmers and improving law and order situation.

Assessment of the heavy metals among suspended particulates and dissolved phases in Suez Canal water

The concentrations and distribution of particulate and dissolved heavy metals, viz: Cu, Zn, Pb, Cd, Fe and Mn have been determined seasonally during 2003 in water samples collected from the Suez Canal. The presented data clarifies that the metals exhibited clear differences in their distribution between particulate and dissolved forms. The concentration of particulate heavy metals ranged between 0.09-3.13, 0.57-15.02, 0.18-3.87, 0.02-0.73, 2.74-49.62 and 0.15-5.08 µg/L for Cu, Zn, Pb, Cd, Fe and Mn, respectively. In the same respect, these values for dissolved forms were 0.28-4.12, 0.57-9.08, 0.27-2.50, 0.02-1.24, 1.94-42.50 and 0.11-3.65 µg/L. The concentrations of particulate metals viz: Zn, Pb, Cd, Fe and Mn were high was compared to the dissolved forms. Dissolved copper, rather than particulate, showed the highest percentage of total copper. The particulate forms of Pb, Cd, Fe and Mn always had higher concentrations than the dissolved forms during the course of study except in the summer season. The northern part of the Suez Canal at Port Said showed mean concentrations of particulate and dissolved Cu=1.43 and 2.10, Zn=8.61 and 3.17, Pb=1.72 and 1.23, Cd=0.35 and 0.35, Fe= 23.49 and 15.83 and Mn=2.09 and 1.82 µg/L. These high concentrations may be attributed to the greater activities, particularly loading and unloading operations at Port Said harbour s industrial effluents and domestic drainage of Port Said city. In contrast, the Sinai side could be considered as reference site, as it was almost clean, i.e., without harmful outfalls, where Cu=0.16 and 0.56, Zn=2.14 and 0.94, Pb=6.29 and 3.44, Cd=0.055 and 0.088, Fe=6.29 and 3.44 and Mn=0.56 and 0.26 µg/L for particulate and dissolved metals respectively.