Studies on the nutritional value of cassava (Manihot utillisima) peels as energy source in the diet of Oreochromis niloticus fry fed in indoor glass aquaria

This study, though, has as its core objective cost reduction in aquaculture nutrition was equally designed to investigate the value of the peels of cassava (Manihot utillisima) as energy source in the diet of Oreochromis niloticus fry. Three levels of cassava peels diet and a control (100% yellow maize in the carbohydrate mixture) was prepared and tested on O. niloticus fry for ten (10) weeks. The fry with mean weight of 0.32g were grouped fifteen (15) in each of the glass aquaria measuring 60x30x30cm with a maximum capacity of 52 litres of water. The fry were fed twice daily at 10% biomass. Weekly, the fry were weighed to determine the weight increment or otherwise and the quality of feed adjusted accordingly. Water quality parameters like temperature, pH and dissolved oxygen (D.0) were monitored and found to be at desirable level. DT 3 (97 % cassava peels and 3% yellow maize) in the carbohydrate mixture gave the best growth performance. The fry fed, this diet gained mean weight of 1.18g for the period of the experiment. However, the poorest performance in terms of growth was from fry fed the control diet (100%yellow maize in the carbohydrate mixture) fry fed this diet gained mean weight of 0.80 for the duration of the experiment. Analysis of the various growth indices like SGR, PER, FCR and NPU shows that DT3 was the overall best diet with an SGR value of2.40 and FCR of 43.83. However, DT 1 (70% cassava peels and 30% yellow maize) gave the poorest SGR of 1.61 and FCR of 67.58. The difference in weight gain among the fry fed the three levels of cassava peels diet and the control was not statically significant (P>0.05)

Parameters for success of Versova multipurpose cooperative in Maharashtra

Fishermen co-operatives can be a potent agency for bringing about the social and economic progress of the fishermen community. Streamlining of marketing procedures and provision of infrastructural facilities would result in lowering of production costs and increased benefits accruing to the producers. Another consequence will be an increase in fish yield whereby the problem of the nutritional food gap can be resolved. Success in cooperation is determined by diverse factors like effective leadership and management, loyal and informed members, availability of adequate and timely finance and infrastructure. Proximity to a large metropolis will also have a significant impact on the creation of a favourable environment.

Effects of gamma radiation on nutritional and microbial quality of Pampus chinensis (Euphrasen 1788)

To evaluate the efficiency of gamma radiation in combination with low temperature Chinese pomfret, Pampus chinensis were preserved by the treatment of different doses of gamma radiation (3, 5 and 8 KGy) at freezing temperature (-20°C) during 90 days of storage period. Quality assessments for fish were carried out at an interval of 15 days during the storage period. Quality assessments were done by organoleptic, chemical (Total Volatile Nitrogen, TVN and Trimethylamine, TMA) and microbiological (Total Bacterial Count, TBC and Total Mould Count, TMC) evaluation. From the analysis of all parameters, maximum shelf-life was observed for irradiated (8 KGy) sample. It remained acceptable up to 75 days and that was the highest duration among 4 types of samples.

Estimations, from tagging experiments, of mortality rates and other parameters respecting yellowfin and skipjack tuna

ENGLISH: In this paper, a method of analysis described by Gulland (1963) has been used to estimate the fishing mortality rates of tagged yellowfin and skipjack tuna for specific areas and years. Fishing mortality rates obtained for tagged tunas will also represent those for the entire population from which the tagged fishes were drawn, provided the assumptions used and corrections made for these analyses are valid. Total mortality rates of tagged fishes have also been computed. These are not assumed to be directly equivalent to the total mortality rates of the untagged populations,since tagged fishes are subject to additional types of attrition. These additional sources of mortality are also examined in this study. SPANISH: En el presente trabajo se ha usado un método de análisis descrito por Gulland (1963), para estimar las tasas de mortalidad de pesca de los atunes aleta amarilla y barrilete marcados en áreas y años específicos. Las tasas de mortalidad de pesca obtenidas en atunes marcados representarán también las de toda la población, de la cual fueron extraídos, previendo que las suposiciones usadas y las correcciones hechas para estos análisis sean válidas. Las tasas de mortalidad total de los peces marcados también han sido computadas. No se supone que éstas sean directamente equivalentes a las tasas de mortalidad total de las poblaciones no marcadas, ya que los peces marcados están sujetos también a otros tipos de pérdida. Estas otras causas de mortalidad son examinadas también en el presente estudio.

An increment technique for estimating growth parameters of tropical tunas, as applied to yellowfin tuna (Thunnus albacares)

ENGLISH: The rate of growth of tropical tunas has been studied by various investigators using diverse methods. Hayashi (1957) examined methods to determine the age of tunas by interpreting growth patterns on the bony or hard parts, but the results proved unreliable. Moore (1951), Hennemuth (1961), and Davidoff (1963) studied the age and growth of yellowfin tuna by the analysis of size frequency distributions. Schaefer, Chatwin and Broadhead (1961), and Fink (ms.), estimated the rate of growth of yellowfin tuna from tagging data; their estimates gave a somewhat slower rate of growth than that obtained by the study of length-frequency distributions. For the yellowfin tuna, modal groups representing age groups can be identified and followed for relatively long periods of time in length-frequency graphs. This may not be possible, however, for other tropical tunas where the modal groups may not represent identifiable age groups; this appears to be the case for skipjack tuna (Schaefer, 1962). It is necessary, therefore, to devise a method of estimating the growth rates of such species without identifying the year classes. The technique described in this study, hereafter called the "increment technique", employs the measurement of the change in length per unit of time, with respect to mean body length, without the identification of year classes. This technique is applied here as a method of estimating the growth rate of yellowfin tuna from the entire Eastern Tropical Pacific, and from the Commission's northern statistical areas (Areas 01-04 and 08) as shown in Figure 1. The growth rates of yellowfin tuna from Area 02 (Hennemuth, 1961) and from the northern areas (Davidoff, 1963) have been described by the technique of tracing modal progressions of year classes, hereafter termed the "year class technique". The growth rate analyses performed by both techniques apply to the segment of the population which is captured by tuna fishing vessels. The results obtained by both methods are compared in this report. SPANISH: La tasa del crecimiento de los atunes tropicales ha sido estudiada por varios investigadores quienes usaron diversos métodos. Hayashi (1957) examinó los métodos para determinar la edad de los atunes interpretando las marcas del crecimiento de las partes óseas o duras, pero los resultados no han demostrado eficacia. Moore (1951), Hennemuth (1961) y Davidoff (1963) estudiaron la edad y el crecimiento del atún aleta amarilla por medio del análisis de las distribuciones de la frecuencia de tamaños. Schaefer, Chatwin y Broadhead (1961) y Fink (Ms.), estimaron la tasa del crecimiento del atún aleta amarilla valiéndose de los datos de la marcación de los peces; ambos estimaron una tasa del crecimiento algo más lenta que la que se obtiene mediante el estudio de las distribuciones de la frecuencia de longitudes. Para el atún aleta amarilla, los grupos modales que representan grupos de edad pueden ser identificados y seguidos durante períodos de tiempo relativamente largos en los gráficos de la frecuencia de longitudes. Sin embargo, ésto puede no ser posible para otros atunes tropicales para los cuales los grupos modales posiblemente no representan grupos de edad identificables; este parece ser el caso para el barrilete (Schaefer, 1962). Consecuentemente, es necesario idear un método para estimar las tasas del crecimiento de las mencionadas especies sin necesidad de identificar las clases anuales. La técnica descrita en este estudio, en adelante llamada la "técnica incremental", emplea la medida del cambio en la longitud por unidad de tiempo, con respecto al promedio de la longitud corporal, sin tener que identificar las clases anuales. Esta técnica se aplica aquí como un método para estimar la tasa del crecimiento del atún aleta amarilla de todo el Pacífico Oriental Tropical, y de las áreas estadísticas norteñas de la Comisión (Areas 01-04 y 08), como se muestra en la Figura 1. Las tasas del crecimiento del atún aleta amarilla del Area 02 (Hennemuth, 1961) y de las áreas del norte (Davidoff, 1963), han sido descritas por medio de una técnica que consiste en delinear las progresiones modales de las clases anuales, en adelante llamada la "técnica de la clase anual". Los análisis de la tasa del crecimiento llevados a cabo por ambas técnicas se refieren al segmento de la población capturada por embarcaciones pesqueras de atún. Los resultados obtenidos por ambos métodos se comparan en este informe.

Catch-per-unit-effort and biological parameters from the Massachusetts coastal lobster (Homarus americanus) resource: Description and trends

Acomprehensive description of the Massachusetts coastal lobster (Homarus americanus) resou,rce was obtained by sampling commercial catches coastwide at sea and at dealerships between 1981 and 1986. Acommercial lobster sea-sampling program, wherein six coastal regions were sampled monthly, with an areal and temporal data weighting design, was the primary source of data. An improved index of catch per trap haul/set-over-day was generated by modeling the relationship between catch and immersion time and standardizing effort. This 6-year time-series of mean annual catch rates tracked closely the landings trend for territorial waters. During the study period there was a gradual increase in indices of exploitation and total annual mortality which corresponded to a gradual decline in mean carapace length of marketable lobster. The frequency of culls escalated from 10.0% in 1981 to 20.9% in 1986, while the percentage of lobster found dead in traps was consistently less than 1%. The sex ratio (%F:%M) was significantly different from 50:50 and approximated a 60:40 relationship during the study period. Male and female weight-length relationships were significantly different. Females weighed more than males at smaller sizes and less than males at larger sizes. A north-south clinal trend was evident wherein lobster north of Cape Cod weighed less at length than those from regions south of Cape Cod. Functional size-maturity relationships were developed for female lobster by staging cement gland development. Proportions mature at size represent more realistic values than those obtained by analyses of percent of females ovigerous. Regional variation occurred in most of the parameters studied. Three lobster groups, differing in major population descriptors, are defined by our data.(PDF file contains 28 pages.)

Plankton periodicity and some physicochemical parameters of the intake channel of Lake Chad

This study examines zooplankton periodicity and some physicochemical parameters of the intake channel of Lake Chad (Nigeria). Nine different zooplankton species were identified at the sampling station 1, while seven different zooplankton species were identified at the sampling station 2 (the intake channel of Lake Chad). Each identified zooplankton species was grouped according to its major group of copepods, Cladocera or Rotifera. The copepods dominated the zooplankton community with the highest numbers of occurrence as Cyclopedia species throughout the course of the study at both station l and 2. There was a clear evidence of the influence of organic manure nutrients on total zooplankton population at station 1 when compared to that of station 2. The water quality variables measured in the course of this study show that the surface water temperature in station 1 ranges from 27.5 degree C to 30.5 degree C. The pH ranges from 6.8 to 8.5, while D.O. contents ranges from 2.9mg/L to 6.1mg/L and alkalinity recorded was 172.00 to 208.00. At the station 2 the water quality parameters obtained show that surface water temperature ranges from 27.3 degree C to 30.2 degree C, pH ranges between 6.9 to 8.5, while the D.O contents ranges from 3.0 mg/L to 6.2 mg/L.Alkalinity ranges from 172mg/L to 212 mg/L

Nutritional and anti-nutritional analyses of Azolla africana Desv. and Spirodela polyrrhiza L. Schleiden as feedstuffs for fish production

The chemical composition of Azolla africana and Spirodela polyrrhiza cultivated in earthen ponds were determined. Crude protein contents of the samples were 28.9~c0.6 and 25.6~c0.2% dry matter for A. africana and S. polyrrhiza respectively. Dry matter, crude fibre and lipid contents of A. africana were higher (P<0.05) than values obtained for S. polyrrhiza. Mineral analyses showed that S. polyrrhiza contained higher levels of Na, S, Ca, Mg and Fe than A. africana. Except for Ca content in S. polyrrhiza, heavy metals (Ni and Zn) accumulation in Azolla were very high. There were no wide differences in the individual amino acid indexes except for methionine. Some anti-nutritional factors were determined. Cyanide, tannin and phytin contents of fresh weed samples were higher than sun-dried samples. A. africana contained more cyanide and tannin than S. polyrrhiza both in fresh and sun-dried forms

Nutritional habits and food consumption pattern of fishing communities around Lake Kainji, Nigeria

The findings are presented of a nutrition survey carried out in the framework of the Nigerian-German Kainji Lake Fisheries Promotion Project in March/April 1995. The major aim of the study was to obtain closer information on the food habits and food consumption patterns of the fishing population, especially the quantification of fish and small fish in particular, consumed at the household level. A standardized questionnaire was used to collect relevant information on demographic, education and occupational profiles; the information was collected in 39 villages in the southern sector of Kainji Lake. (PDF contains 75 pages)

The nutritional status of pre-school children, Kainji Lake communities, Nigeria: a baseline survey

This survey was carried out to provide the Kainji Lake Fisheries Promotion Project (KLFPP), whose overall goal is the improvement of the standard of living of fishing communities around Kainji Lake, Nigeria, and an increase in the availability of fish to consumers, with nutritional status baseline data for long-term monitoring and evaluation of the overall project goal. In a cross-sectional survey, baseline anthropometric data was collected from 768 children, aged 3-60 months in 389 fisherfolk households around the southern sector of Kainji Lake, Nigeria. In addition, data was collected on the nutritional status and fertility of the mothers, vaccination coverage of children and child survival indicators. For control purposes, 576 children and 292 mothers from non-fishing households around Kainji Lake were likewise covered by the survey. A standardised questionnaire was used to collect relevant information, while anthropometric measurements were made using appropriate equipment. Data compilation and analysis was carried out with DATAEASE registered and EPI-INFO registered software, using NCHS reference data for the analysis of anthropometric measurements. The prevalence of stunted children in fishing households was high at 40%, while the prevalence of wasted and underweight children was likewise high at 10% and 29% respectively. Children from non-fishing households had a marginally lower prevalence of stunting, wasting and underweight with 37%, 7% and 25 % respectively, although these differences were not statistically significant. Considering the fact that the survey was carried out during a period of relative food abundance, the prevalence of wasting and underweight children is likely to be much higher during periods of food shortage. The prevalence of stunting, wasting and underweight was relatively high for children aged 3 to 23 months, suggesting an increased risk of malnutrition during this period, most likely associated with inadequate weaning practices. The prevalence of malnourishment amongst women of child-bearing age was relatively high, irrespective of occupation of the household, with an average of 11% undernourished and 6% wasted. Vaccination coverage was very low while infant and child mortality were extremely high with about 1 in 5 children dying before their fifth birthday. Based on the ethical obligation to maximise the potential benefits of the survey, recommendations for activities to improve community nutrition and health were made for communication to relevant authorities. (PDF contains 52 pages)

The nutritional status of pre-school children, Kainji Lake communities, Nigeria: a follow-up survey

This survey was carried out to provide the Kainji Lake Fisheries Promotion Project (KLFPP), whose overall goal is the improvement of the standard of living of fishing communities around Kainji Lake, Nigeria, managing the fisheries on a sustainable basis, with follow-up data for long-term monitoring and evaluation of the overall project goal. A similar survey, conducted in 1996, provided the baseline against which data from the current survey was evaluated. In a cross-sectional survey, anthropometric data was collected from 576 children aged 3-60 months in 282 fisherfolk households around the southern sector of Kainji Lake, Nigeria. In addition, data was collected on the nutritional status and fertility of the mothers, vaccination coverage of children and child survival indicators. For control purposes, 374 children and 181 mothers from non-fishing households around Kainji Lake were likewise covered by the survey. A standardised questionnaire was used to collect relevant data, while anthropometric measurements were made using appropriate equipment. Data compilation and analysis was carried out with a specially designed Microsoft Access application, using NCHS reference data for the analysis of anthropometric measurements. Statistical significance testing was done using EPI-INFO" software. The results of the follow-up survey indicate a slight increase in the percentage of stunted pre-school children in fishing households around Kainji Lake, from 40% in 1996 to 41% in 1999. This increase is however not statistically significant (p= 0.704). Over the same period, the percentage of stunted children in non-fishing households increased from 37% to 39% (p= 0.540), which is also not statistically significant. Likewise, there were no statistically significant differences between the 1996 and 1999 results for the prevalence of either wasted or underweight children in fishing households. The same applies to children from non-fishing households. In addition, vaccination coverage remains very low while infant and child mortality rates continue to be extremely high with about 1 in 5 children dying before their fifth birthday. There has been no perceptible and lasting improvement in the standard of living of fishing households over the course of the second project phase as indicated by the persistently high prevalence of stunting. The situation is the same for the control group, indicating that for the region as a whole, a number of factors beyond the immediate influence of the project continue to negatively impact on the standard of living. The results also show that the project activities have not had any negative long-term effect on the nutritional status of the beneficiaries. (PDF contains 44 pages)

The assessment of physico-chemical parameters of Shiroro Lake and its major tributaries

The physico-chemical parameters of the surface water of Shiroro Lake and its major tributaries at their entry point to the reservoir were assessed over a period of eighteen months. As in other African inland water bodies there were seasonal variations in the parameters measured. The hydrological regime of the lake, precipitation chemistry, bedrock chemistry and hydro-electric power generation influence and determine the inputs of dissolved organic carbon, nutrient levels and water quality of the lake. The added nutrients to the lake by means of the major tributary rivers and inundation of surrounding areas also influence the water quality of the lake. The wet season mean values for water and air temperature were significantly (P <0.05) higher than dry season mean values in all stations. However, for pH, Dissolved oxygen and Phosphate-phosphorus the dry season mean values were higher than wet season mean values

The relationship between some physicochemical parameters and plankton composition on fish production in ponds

The effect of physico-chemical parameters and plankton composition on fish production in ponds was investigated in six fish farms for eight weeks. The physicochemical parameters investigated were temperature=25-30 plus or minus C, transparency=0.45-0.57m, dissolved oxygen=3.0-10.9mg/l, pH=6.0-7.7, dissolved carbon dioxide=5.46-28.3mg/l, total alkalinity=44.37-80.0ppm, chemical oxygen demand=31.88-72.18mg/l and biological oxygen demand=0.66-48.34mg/l. Plankton composition varies and was made of four families of phytoplankton namely; Cyanophyceae, Chlorophyceae, Dinophyceae and Diatomida; and four families of zooplankton viz; Protozoa, Rotifera, Copepoda and Dinoflagellates. Farm 1 and 6 recorded the highest average weight of about 1.0kg and average total length of about 40.0cm for the two fish species. This study showed that fish yield was dependable on the quality and management of pond water characteristics

The relationship between some physicochemical parameters and plankton composition on fish production in ponds

The effect of physico-chemical parameters and plankton composition on fish production in ponds was investigated in six fish farms for eight weeks. The physicochemical parameters investigated were temperature=25-30 plus or minus C, transparency=0.45-0.57m, dissolved oxygen=3.0-10.9mg/l, pH=6.0-7.7, dissolved carbon dioxide=5.46-28.3mg/l, total alkalinity=44.37-80.0ppm, chemical oxygen demand=31.88-72.18mg/l and biological oxygen demand=0.66-48.34mg/l. Plankton composition varies and was made of four families of phytoplankton namely: Cyanophyceae, Chlorophyceae, Dinophyceae and Diatomida; and four families of zooplankton viz: Protozoa, Rotifera, Copepoda and Dinoflagellates. Farm 1 and 6 recorded the highest average weight of about 1.0kg and average total length of about 40.0cm for the two fish species. This study showed that fish yield was dependable on the quality and management of pond water characteristics

Growth parameters for Lates niloticus (L.), Bagrus docmak (Forsskal), Oreochromis niloticus (L.), Clarias gariepinus (Burchell) and Synodontis species derived from tag returns

In a tagging experiment carried out in the Kenyan waters of Lake Victoria, an annual growth increment of 29 cm yr was obtained for Lates niloticus (L.). Growth parameters obtained using the von Bertalanffy model on the growth curve fitted by eye were L (inf.) = 122 cm yr and k = 0.26 yr. Data for other species tagged were inadequate to obtain meaningful results.