The use of aerial photographs for estimating school sizes of cetaceans

ENGLISH: The accuracy and precision of dolphin school size estimates based on aerial photograph counts were examined using data collected on recent aerial and ship surveys. These estimates were found to be accurate during a 1979research cruise aboard a tuna purse-seiner; dolphin schools were photographed from the ship’s helicopter, encircled with the purse-seine, and then counted as the dolphins were released from the net. A comparison of photographic estimates with these counts indicated that the relationship was fairly close and gave no indication of significantly differing from 1:1. During a 1980 aerial study, photographic estimates from different schools, passes, and camera formats were compared and were found to be quite precise with a standard deviation of approximately 60/0 of school size. Photographic estimates were also compared with estimates made by aerial observers. Most observers tended to underestimate school size, particularly for large schools. The variability among observers was high, indicating that observers should be individually calibrated. SPANISH: Se examinó la exactitud y la precisión de las estimaciones de la magnitud de los cardúmenes de delfines basadas en el cálculo de las fotografías aéreas, usando los datos obtenidos en los últimos reconocimientos aéreos y de los barcos. En 1979, durante un crucero de investigación en un cerquero atunero, se encontró que estas estimaciones eran acertadas; se fotografiaron los cardúmenes de delfines desde un helicóptero del barco, cercados con la red y luego se contaron a medida que se libraban los delfines de la red. Una comparación de las estimaciones fotográficas con estos cálculos indicó que la relación era bastante aproximada y no hubo indicación que se diferenció significativamente de la razón 1:1. Durante un estudio aéreo en 1980, se compararon las estimaciones fotográficas de diferentes del cardúmenes, en los pases y los formatos de las cámaras y se encontró que eran bastante precisos, con una desviación normal de cerca del 60/0 de la magnitud cardumen. Se compararon también las estimaciones fotográficas con las estimaciones realizadas por los observadores aéreos. La mayoría de los observadores tienden a subestimar la magnitud de los cardúmenes, especialmente los cardúmenes grandes. La variabilidad entre los observadores fue elevada, lo que indica que se deben calibrar individualmente los datos de observadores. (PDF contains 39 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)

Modified sorting technique to mitigate the collateral mortality of trawled school prawns (Metapenaeus macleayi)

The potential for changes to onboard handling practices in order to improve the fate of juvenile school prawns (Metapenaeus macleayi) discarded during trawling were investigated in two Australian rivers (Clarence and Hunter) by comparing a purpose-built, water-filled sorting tray against a conventional dry tray across various conditions, including the range of typical delays before the start of sorting the catch (2 min vs. 15 min). Juvenile school prawns (n= 5760), caught during 32 and 16 deployments in each river, were caged and sacrificed at four times: immediately (T0), and at 24 (T24), 72 (T72), and 120 (T12 0) hours after having been discarded. In both rivers, most mortalities occurred between T0 and T24 and, after adjusting for control deaths (<12%), were greatest for the 15-min conventional treatment (up to 41% at T120). Mixed-effects logistic models revealed that in addition to the sampling time, method of sorting, and delay in sorting, the weight of the catch, salinity, and percentage cloud cover were significant predictors of mortality. Although trawling caused some mortalities and comparable stress (measured as L -lactate) in all school prawns, use of the water tray lessened the negative impacts of some of the above factors across both the 2-min and 15-min delays in sorting so that the overall discard mortality was reduced by more than a third. When used in conjunction with selective trawls, widespread application of the water tray should help to improve the sustainability of trawling for school prawns.

Physical soil characteristics of waterlogged and saline lands of five districts of Haryana, India

Physical characteristics of waterlogged and saline soils of five districts, namely Rohtak, Faridabad, Gurgaon, Sonipat and Jhajjar, of Haryana were studied to evaluate the aquaculture potential. The soil samples from 76 sites were procured and analysed for pH, electrical conductivity, soil particles and water retention capacity, since the knowledge of these parameters is essential for the preliminary evaluation of a site for aqua-farming. Six soil types were identified and clay-loam was observed to be the maximum at 45 (59.21%) sites, followed by silty-clay loam at 14 (18.42%), sandy-clay loam at six (7.89%), silty-loam at four (5.26%), sandy-loam at four (5.26%) and loam at three (3.94%) sites. The pH of soil indicated moderate to high alkaline conditions ranging between 8.01and 9.00 at 53 (69.73%) sites, 9.01 and 10.00 at 17 (22.36%) sites, and low between 7.01 and 8.00 at six (7.89%) sites. The electrical conductivity was found to range between <1 and 10 mmho cmˉ¹ with the value of <1.0 mmho cmˉ¹ at 36 (47.36%) sites. The water retention capacity was observed mostly to be moderate. The paper describes the interrelationship between these parameters with reference to the suitability for aqua-farming.

Comparative economic analysis of pond fish production in Mymensingh and Jessore Districts, Bangladesh

The study was conducted to determine the cost, return and relative profitability of pond fish production of Mymensingh and Jessore districts. A total of 75 ponds were selected on the basis of purposive random sampling technique from 7 villages under 2 Upazila (Trishal and Gouripur) of Mymensingh districts and 8 villages under 4 Upazila (Monimmpur, Jhikorgacha, Chowgacha and Sadar) of Jessore district. It was found that per hectare per year gross cost of pond fish production in Mymensingh and Jessore were Tk 333457.75 and Tk 54327.74, while gross return were Tk 434131.16 and Tk. 96640.00 and net return were Tk 100673.41 and Tk. 42312.26, respectively. The findings of this study revealed that the pond fish production in Jessore district was more profitable than that of Mymensingh district. Cobb-Douglas production function was applied to realize the specific effect of the factors on pond fish production. Out of six variables included in the function three variables had positive impact on return from pond fish production, in Mymensingh district but five variables had positive impact on return from pond fish production in Jessore district

Input-output relationship and economics of pangas monoculture and carp-pangas polyculture in two districts of Bangladesh

An attempt was made to study the input-output relationships and economics of pangas monoculture and carp-pangas polyculture in Bangladesh. By analyzing the data collected from 50 pangas farms and 55 carp-pangas farms, the study has investigated the production systems of two technologies and the effects of fingerling stocking and applications of feed and fertilizer on fisheries income. The data were collected from the fishermen of Trishal and Bhaluka of Mymensingh district, and Kahaloo and Adamdighee of Bogra district during 2001-02. For pangas monoculture, the stocking density was 31,561 per ha while it was 55,017 per ha in carp-pangas polyculture. Most of the farmers used urea, TSP and lime before stocking. Rice and wheat bran happened to be the most common feed ingredients for both types of culture in general. Other important ingredients used were mustard oil-cakes, rice polish, wheat flour, fish meal, bone meal, soybean meal and poultry litter. In terms of quantities, rice bran and wheat bran dominated the farmers list. Rice and wheat bran together constituted about 60% of all studied feeds. Feed cost constituted 59.13% of total costs for pangas monoculture and 67.44% for carp-pangas polyculture. Per ha productions of pangas and carp-pangas in a single culture cycle were 15,508 kg and 19,745 kg, respectively. Per ha gross profits were estimated to be Tk 310,311 and Tk 464,418 for pangas monoculture and carp-pangas polyculture, respectively. Net profit appeared to be Tk 264,216 per ha for pangas monoculture and Tk 416,509 per ha for carp-pangas polyculture. The BCRs calculated were 1.46 and 1.68 for monoculture and polyculture, respectively. The break-even costs per kg of fish were estimated at Tk 36.93 for pangas and Tk 30.93 for mixed species which was much lower than the prices the producers received. Break-even productions were estimated at 10,702 kg per ha for pangas monoculture and 11,784 kg per ha for carp-pangas polyculture. Fingerling and feed cost, and pond size significantly explained the variation of income from pangas monoculture. These factors have significantly influenced the income from the crop. Functional analysis shows that 1% increase in the feed cost might increase 0.51% of pangas income and 0.41% in carp-pangas income. No other inputs had shown this much of responses to increasing income from a fish.

Adoption, productivity and profitability of rice-fish and fingerling culture in three selected districts of Bangladesh

The study aimed to investigate the productivity and profitability of rice-fish farming. It also determined the factors affecting rice-fish and fingerling production in Bangladesh. Among the total respondents about 55% were involved in rice-fish farming, 37% in pond fish culture and rest 9% in fish nursery. Integrated rice-fish farming contributed about 83% of the annual farm income in Comilla while it was about 20% in both Kishoregonj and Chandpur districts. Among the different farming systems integrated rice-fish culture and rearing fingerlings in the nursery pond were more profitable at the farm level. Farmers earned a net return of Tk. 49,714/ha from integrated fish culture with boro rice while the net return of boro rice-alone was only Tk. 11,179/ha. This indicated that farmer could earn 218% higher net return from integrated rice-fish farming than that of boro rice only farming. Moreover, integrated rice-fish culture also reduced pesticides cost to about 77% and weeding cost to about 51% in boro season. Fingerling nursing earned highest net returns among the three technologies.

Fisheries profile mapping of coastal districts in Maharashtra state through GIS

In recent times, GIS is being increasingly used as a decision support system for management of fisheries and aquaculture. It provides new innovative approaches of the dynamic relations that characterize this sector. In this context, a study is conducted based on the secondary data of a major maritime state, Maharashtra, where mapping of fisheries profile of coastal districts in the state is performed through GIS tool having critical geographic dimensions. This paper aims to map information of the state which can be used for the purpose of planning and decision making as each aspect of map has a different component involved. For this purpose, at the core of the system, the data were accessed and integrated from different sources mainly from the five coastal districts of Maharashtra state. Data were brought in tabular form through Microsoft Excel and then joined to Map info Professional version 8.0 GIS software was used with the digitized map of Maharashtra state to enable mapping. This was further synchronized and integrated to generate four thematic maps searchable on several criteria. Map 1 contains the searchable criteria as regards to the fish growth for the year 1997-2004 and fish seed production for the year 2003-04. Map 2 contains fisher population along with their occupation for the year 1992. Map 3 contains brackish water and shrimp farming production and culture area. Map 4 contains infrastructural facilities which include type of boats etc. With this mapping, planners and various stakeholders have accessible information as regards to the various components of fisheries in the state of Maharashtra.

Malaysian school engages in bullfrog and turtle farming

A brief description is given of the culture methods used in the Sepang Today Aquaculture Centre, a private aquafarming training school in Malaysia, regarding American bullfrog (Rana catesbeiana) and the soft-shelled turtle (Trionyx sinensis). Seed production, grow-out, marketing and future potential are discussed, referring to the school s training brochures for both culture methods.