Consumption to biomass (Q/B) ratio and estimates of Q/B-predictor parameters for Caribbean fishes

Estimates of the Q/B ratio and parameters of equations to 'predict' Q/B values for 116 fish stocks in the Gulf of Salamanca, Colombia are presented. A compilation of these estimates available for Caribbean Sea fishes (264 stocks) is also provided for comparison purposes. General trends in the value of Q/B resulting from differences in the equation and parameter values used are briefly discussed.

Estimating the food consumption of fishes: one step in linking a species with its ecosystem

Details are given of a new software package MAXIMS which may be used to estimate the daily food consumption of fish. The software estimates the feeding times, the rates of ingestion and evacuation and related parameters. Two applications of the program are described. The first pertains to anchovy (Engraulis ringens ) with one feeding period per day, and the second one to juvenile cod (Gadus morhua ), which feed during dawn and dusk.

Fish demand and supply projections

It has been predicted that the global demand for fish for human consumption will increase by more than 50% over the next 15 years. The FAO has projected that the increase in supply will originate primarily from marine fisheries, aquaculture and to a lesser extent from inland fisheries, but with a commensurate price increase. However, there are constraints to increased production in both marine and inland fisheries, such as overfishing, overexploitation limited potential increase and environmental degradation due to industrialization. The author sees aquaculture as having the greatest potential for future expansion. Aquaculture practices vary depending on culture, environment, society amd sources of fish. Inputs are generally low-cost, ecologically efficient and the majority of aquaculture ventures are small-scale and family operated. In the future, advances in technology, genetic improvement of cultured species, improvement in nutrition, disease management, reproduction control and environmental management are expected along with opportunities for complimentary activities with agriculture, industrial and wastewater linkages. The main constraints to aquaculture are from reduced access to suitable land and good quality water due to pollution and habitat degradation. Aquaculture itself carries minimal potential for aquatic pollution. State participation in fisheries production has not proven to be the best way to promote the fisheries sector. The role of governments is increasingly seen as creating an environment for economic sectors to make an optimum contribution, through support in areas such as infrastructure, research, training and extension and a legal framework. The author feels that a holistic approach integrating the natural and social sciences is called for when fisheries policy is being examined.

The role of small indigenous fish species in food and nutrition security in Bangladesh

In Bangladesh, only 6% of the daily food intake is animal food of which fish accounts for 50%. Rice is the mainstay, making up 60% of the daily food intake. However, many nutrients such as vitamins A and C, iron, calcium, zinc and iodine are not found in rice and have to be obtained from other sources. Small indigenous fish are a vital contribution to the diet of the rural poor in Bangladesh, where more than 30,000 children go blind every year from vitamin A deficiency and 70% of women and children are iron-deficient. Small fish, which are less than 10 cm in length and usually eaten whole with the organs and bones, contain large amount of calcium and possibly iron and zinc. The largest fish promoted in aquaculture do not contribute significantly to calcium intake. Some species also contain large amount of vitamin A. Much of the small indigenous fish (SIS) of Bangladesh are caught in floodplains and natural waterbodies. Small fish are eaten frequently in small amounts and are more equally distributed among family members than big fish of which men get the larger share. Unfortunately, overfishing and the deterioration of natural habitats have resulted in a decline in SIS. When measures are taken to improve food and nutrition security, there should be a focus on production of small fish so that greater quantities are accessible for consumption by the rural poor.

Improving aquaculture feed in Bangladesh: From feed ingredients to farmer profit to safe consumption

Use of manufactured feeds in aquaculture in Bangladesh has grown rapidly over the last five years. More than 1 million tonnes of commercially formulated feeds and 0.3-0.4 million tonnes of farm-made feeds were produced in 2012, and sectoral growth is projected to increase substantially over the medium term. This working paper summarizes findings from a study, conducted as part of the WorldFish/USAID “Feed the Future-Aquaculture” project in 2012, assessing the current status of the aquaculture feed sector in Bangladesh. Fish feed value chains, market trends, ingredients and formulation systems, farm feeding practices, ancillary services and feed regulations were investigated. The study identifies a number of entry points for interventions in the sector, and investments which would improve feed quality and farmer access to better feeds and support the growth of sustainable aquaculture.

Assessment of contaminant body burdens and histopathology of fish and shellfish species frequently used for subsistence food by Alaskan Native communities

Subsistence food items can be a health concern in rural Alaska because community members often rely on fish and wildlife resources not routinely monitored for persistent bioaccumulative contaminants and pathogens. Subsistence activities are a large part of the traditional culture, as well as a means of providing protein in the diets for Tribal members. In response to the growing concerns among Native communities, contaminant body burden and histopathological condition of chum and sockeye salmon (Oncorhynchus keta and Oncorhynchus nerka) and the shellfish cockles and softshell clams (Clinocardium nuttallii and Mya arenaria) were assessed. In the Spring of 2010, the fish and shellfish were collected from traditional subsistence harvest areas in the vicinity of Nanwalek, Port Graham, and Seldovia, AK, and were analyzed for trace metals and residues of organic contaminants routinely monitored by the NOAA National Status & Trends Program (NS&T). Additionally, the fish and shellfish were histologically characterized for the presence, prevalence and severity of tissue pathology, disease, and parasite infection. The fish and shellfish sampled showed low tissue contamination, and pathologic effects of the parasites and diseases were absent or minimal. Taken together, the results showed that the fish and shellfish were healthy and pose no safety concern for consumption. This study provides reliable chemistry and histopathology information for local resource managers and Alaska Native people regarding subsistence fish and shellfish use and management needs.

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

Effect of salinity on food consumption and growth of juvenile Nile tilapia (Oreochromi niloticus L.)

The effect of salinity (0, lO and 20%o, water temperature 28 ± l oC) on food consumption and growth of juvenile Nile tilapia, Oreochromis niloticus L. (9.94 ± 0.15 g) were investigated by feeding group of 20 fish at 2% body weight day. Individual food consumption was measured using X-radiography. There were no significant differences in growth or white muscle protein concentrations among groups. During feed deprivation, weight loss was similar for fish held at O%o and 10 %o salinity, but after 7 days over 50% of the fish maintained at 20%o salinity developed lesions covering 5-25% of the body. No significant relationships were observed between individual specific growth rates and food consumption rates within the groups. The fish in all salinity groups showed a negative correlation between specific growth rate and food conversion ratio. The coefficient of variation for wet weight specific food consumption and the mean share of meal for each fish were used as a measure of social hierarchy strength. A negative correlation was observed between coefficient of variation in food consumption and mean share of meal. The social hierarchy structure was similar in all salinities; 25% of the fish were dominant (18.29% above an equal share of meal) and 30% were subordinate (16.19% below an equal share of meal) and the remainder 45% fish fed theoretical share of meal (MSM, 5.26%).

Effect of benzocaine on opercular movement and oxygen consumption in Channa punctatus (Bloch)

Effect of anaesthetization with benzocaine at the rate of 18.0 mg.1super(-1) on juveniles of Channa punctatus was observed using a cylindrical glass respirometer. Oxygen consumption and opercular movement were studied at 3h and 24h of anaesthetization. The oxygen consumption of control fish increased linearly from 0.183±0.029 to 0.481±0.034 mlO sub(2).h super(-1) with an increase in body weight from 1.45±0.18 to 6.12±0.11g and showed a reduction (p<0.001) of about 41% in 3h and 37% in 24h anaesthetization of Benzocaine. Similarly, the opercular movement of control fish ranging between 46±1 to 49±1min super(-1) came down to show a reduction (p<0.001) of 43% and 38% respectively in 3h and 24h anaesthetization. The information is useful in calculation of oxygen requirement of this species for live transportation and other experimental purpose.

Impact of small indigenous species of fish (SIS) on livelihood of local fishing community in two upazilas of Mymensingh

The fisher folk used to catch small indigenous species of fish (SIS) from rivers, canals, wetlands and floodplains at little or no cost for their livelihood. Surplus fish was sold at the local market to generate some little capital for the households. The livelihood and consumption of SIS in fishing community of two upazilas viz. Trisal and Ishwarganj under Mymensingh district were studied for 3 months in 2004. Most of the fisher folk of the study areas belong to resource-poor section of the society living below the poverty level. Majority of them had no cultivable land. As professional fishers they face many problems during lean fishing period from January to April due to little or non-availability of fish. Majority of the fisher households consumed SIS three to four days a week. The fisher households of Trisal upazila consumed more small fish than those of Ishwargonj upazila. More than 50% respondents consumed <20 g SIS/day and 20% consumed >40 g SIS/day in Trisal upazila. On the other hand, in Ishwargonj upzila, most of the fisher households (66%) were found to consume <20 g SIS/day. SIS was mostly available from July-December in rivers, wetlands (beels), and canals, and income from fishing was reported to be good. The dominant SIS was Puntius spp., Mystus spp., Anabas testudineus, catfishes, mola, and small prawns. Non-indigenous species like tilapia was also dominant in Trisal upzila where aquaculture practices were well established.

Shifting rice farming to fish culture in some selected areas of Mymensingh, Bangladesh: the process, conflicts and impacts

The evolutionary process of converting low-lying paddy fields into fish farms and its impact on agrarian communities in some selected areas of Mymensingh district were studied. This study was conducted through participatory rural appraisal (PRA) covering 12 villages from each of selected upazillas viz. Fulpur and Haluaghat of Mymensing [sic] district. A total of 12 PRA sessions were conducted where 90 farmers participated during 29 July to 26 August 2004. It is seen that the use of low-lying paddy fields was mostly confined to Broadcast Aman (B. Aman) rice production until 1960s. With the introduction of modern rice farming technology, the farmers started to produce Boro rice in Rabi season and B. Aman rice in Kharif season. With the passage of time, aquaculture technologies have been evolved and the farmers realized that fish farming is more profitable than rice cultivation, and then they started to utilize their paddy fields for alternate rice-fish farming and rice-cum-fish farming. Now a days, aquaculture based crop production system is in practice in more than 25% of the low-lying paddy fields. Conversion of rice fields in to fish ponds has brought up a change in the livelihood patterns of the rural farmers. The areas where the farmers involved themselves in the new production systems were fingerling collection, transportation and marketing of fry and fingerlings. During 1960s to 1970s, a few people used to culture fish in the permanent ponds for their own consumption, the species produced were rohu, catla, mrigal, ghainna, long whiskered catfish, freshwater shark (boal), snake head (shol) etc. Small fishes like climbing perch, stinging catfish, walking catfish, barb, minnows etc. were available in the rice fields during monsoon season. In 1980s to mid 1990s, some rice fields were converted into fish ponds and the people started to produce fish for commercial purposes. When rice-fish farming became profitable, a large number of people started converting their rice fields in to rice-fish culture ponds. Culture of some exotic fishes like silver carp, tilapia, grass carp, silver barb etc. also started in the paddy fields. Higher income from fish farming contributed positively in improving the housing, sanitation and education system in the study areas. It is seen that the medium and medium high lands were only used for alternate rice fish farming. The net income was high in any fish based cropping system that motivated the farmers to introduce fish based cropping system in the low-lying inland areas. As a result, the regional as well as communal income disparities occurred. However, the extraction of ground water became common during the dry period as the water was used for both rice and fish farming. Mass conversion of paddy fields into rice-fish culture ponds caused water logging in the study areas. In most cases, the participated farmers mentioned that they could be easily benefited by producing fish with T. Aman or only fish during the monsoon season. They agreed that this was an impressive technology to them and they could generate employment opportunities throughout the year. Finally, the social, economic and technical problems which are acting as constraints to rapid expansion of fish production system were reported from the interviewee.

Sequential analysis for testing quality standard of fish ham and sausage

Fish sausages are finely ground fish flesh, either of a single species or mixed, homogenised with starch, sugar, fat, spices and preservatives, generally filled in cylindrical synthetic or natural casings and pasteurised. Similar products containing small pieces of quality fish and lard are termed "fish ham". They are highly relished products in Japan, annual consumption exceeding 2 lakh tones. Preliminary studies have shown that they can catch a lucrative market in our country. However, being a pasteurised product which is often consumed as such without any further cooking, strict quality control measures have to be enforced so as to avoid food poisoning hazards. Besides physical characteristics like absence of damages, pin-holes, curliness and air pockets as well as jelly strength, texture and flavour, chemical characteristics like pH and acid values, moisture, carbohydrate and fat contents and volatile bases have to be assessed. A very important test that has to be carried out along with the above, before passing a lot for free distribution is the bacteriological examination to avoid the presence of pathogenic organisms.

Quality characteristics of cured fish of commerce

A survey was conducted at the fish curing yards at Shakthikulangara (Quilon), fish market at Vizhinjam, fish curing yards, fish market as well as dry fish godowns in and around Tuticorin. A total of 23 samples of different varieties of fishes collected from the markets and curing yards and 8 samples of anchovies collected from different godowns at Tuticorin were analysed to evaluate the quality and extent of fungal and insect infestation. Samples were analysed for proximate composition and estimated their water activity. About 70% of the 23 samples of different varieties of fish were found to be unfit for consumption and 12.5% of the samples of anchovies were found to be infested with beetle, after 3 weeks of storage after collection from these centres.

Feeding habits and trophic levels of some demersal fish species in the Persian Gulf (Bushehr Province) using Ecopath model

A trophic study was carried out in February of 2012 to January 2013 on the ecosystem in the Persian Gulf, Bushehr provience. A total of 2,948 samples of stomach contents were analyzed based on the weight and number of food items and were identified about 40 preys. Crustacean and bony fish were as a main prey in most of the stomach contents . The mean average trophic level was estimated at 3.6 by Ecopath software. In this research, the mean level were studied between eight species varied from 3.47 to 4.61, Saurida tumbil occupy the highest and the Argyrops spinifer was the lowest level. The ranges of total mortality varied from 0.7 to 3.05 per years. The food consumption rate was estimated about 69.82 per year. The overlap index showed that the prey items such as fish, crustacean, bivalve and echinoderm were shared about 65, 15, 15 and 6 percent in all stomach of individual in respectively. Mixed trophic analysis indicates that benthos have a positive effect on most of the fish species. Most species have a negative impact on themselves, interpreted here as reflecting increased with in group competition for resources. This preliminary model can be helpful to determine the gaps in the present knowledge about demersal system of the Persian Gulf.

Production and quality assessment of fish pickles from mola (Amblypharyngodon mola) fish

Fish pickles (with olive and tamarind) were prepared from mola fish (Amblypharyngodon mola) and their nutritional and food quality were assessed. The quality of the pickle prepared with olive was excellent and the pickle prepared with tamarind was found good. Moisture content of the two pickle products were 43.85% (with tamarind) and 50.89% (with olive). The protein and lipid contents of tamarind added pickle were 19.13 and 35.64% respectively; pickle with olive contained less protein (13.16%) compared to tamarind added mola pickle. Lipid contents were almost same in both cases. Ash content of two pickles was also found similar (1.00%). The quality of mola pickles stored either in cool condition (4°C) with vinegar or at room temperature with Na-benzoate were found good for consumption up to 90 days of storage. All of the fish pickles preserved under different condition were found in acceptable condition up to 240 days storage and pickle with vinegar stored at 4°C was found good for consumption at the end of 240 days.