Mrityunjoy Kunda - Academia.edu (original) (raw)

Papers by Mrityunjoy Kunda

Egyptian Journal of Aquatic Biology and Fisheries, Nov 1, 2022

The experiment was carried out for 94 days in the renowned Ratargul Freshwater Swamp Forest of Ba... more The experiment was carried out for 94 days in the renowned Ratargul Freshwater Swamp Forest of Bangladesh in order to assess the production performance and economics among three locally high-demand catfish species with a view to selecting suitable species for cage culture. Magur (Clarias batrachus), pabda (Ompok pabda) and pangas (Pangasianodon hypophthalmus) were stocked in Treatment-1 (T 1), Treatment-2 (T 2) and Treatment-3 (T 3), respectively at stocking densities of 40 fish/m 3

Aquaculture Research, Oct 1, 2008

An integrated aquaculture of freshwater prawn (Macrobrachium rosenbergii) and self-recruiting sma... more An integrated aquaculture of freshwater prawn (Macrobrachium rosenbergii) and self-recruiting small ¢sh mola (Amblypharyngodon mola) was conducted in farmers' rice ¢elds at Mymensingh, Bangladesh. There were four treatments with three replications. Four stocking densities, 10 000, 15000, 20 000 and 25000 ha À 1 , of freshwater prawn were applied. The stocking density of mola was the same (20 000 ha À 1) in all treatments. During land preparation, triple super phosphate (TSP) and murate of potash (MP) were applied at the rate of150 and 75 kg ha À 1 respectively. Urea was applied at the rate of 200 kg ha À 1 in equally distributed three installments after16,45 and 65 days of rice plantation. Prawns were fed with commercial pelleted feed at 3^8% body weight. All water quality parameters were found to be within the suitable range for freshwater prawn culture. There was a homogenous abundance of plankton communities in all treatments. The results of a 4-month culture period showed that the average production of prawn ranged from 222 to 388 kg ha À 1 , mola 51 to 68 kg ha À 1 and rice 2880 to 3710 kg ha À 1. Signi¢cantly higher production of both prawn and mola was recorded in the plots where the freshwater prawn stocking density was 15000 ha À 1. This treatment resulted in a net pro¢t of USD 1100 ha À 1 .

An investigation on growth, production and fishery of three Indian major carps: rohu, Labeo rolzi... more An investigation on growth, production and fishery of three Indian major carps: rohu, Labeo rolzita, ca tla, Catla catla and mrigal, Cirrlzinus mrigala and three exotic carps: silver carp, Hypoplzthalmichth:ys molitrix, grass carp, Ctenopharyngodon idella, and common carp, Cyprinus cmpio was carried out in Nasti baor during February to April months. In catch per unit effort (CPUE) study the highest catch/day/person (3.13 kg) and catch/day/gear (40.65 kg) was recorded in the month of lv1arch for lwchal fishing. In hamar fishing catch/day/person (15.08 kg) and catch/day/gear (1206 kg) was also found higher in March. Komar fishing was done only in March and April and its CPUE was greater in both the months than that of hoclzal. The average recovery rate (combination of all six species) was 37.80 considering the stocking from July month of the previous year. The recovery rate of common carp (54.1) was the highest and lowest (13.90) in case of silver carp. When the recovery was calculated on the basis of one year data and stocking, it was 55.6%. Analysis of production model revealed that the present production (54,806 kg/year) is less than both theoretical production (model I-85,285 kg/year and model II-75,952 kg/year) estimated. Therefore, it may be concluded that the fish production from Nasti baor could still be increased from the present level of production.

Social Science Research Network, 2021

Gorai River is one of the important rivers in Bangladesh for rich aquatic biodiversity. The river... more Gorai River is one of the important rivers in Bangladesh for rich aquatic biodiversity. The river is originated from the Ganges-Padma River system, a trans-boundary river between India and Bangladesh. Once the river was rich in fish biodiversity, but due to man-made and natural causes the availability of fish reduced drastically. A comprehensive analysis of fish diversity indices, gear efficiency, catch composition and decline causes of fish diversity in Gorai River, Bangladesh was accompanied. The data were collected monthly basis from January to December 2018 from four major fishing sites of the river. A total of 62 fish and 2 prawn species under 12 orders and 24 families were recorded. Cypriniformes was the leading order consisting 27% of the total catch. The overall values of Shannon-Weaver diversity (H'), Margalef’s richness (d) and Pielou’s evenness (J') indices were recorded as 1.478, 15.115 and 0.481, respectively. The highest and lowest CPUE were recorded from seine net (5.2±1.72 kg gear-1 haul-1) and hook & long lines (0.0135±0.0015 kg gear-1 haul-1), respectively whereas, highest and lowest gear efficiency were recorded from lift net (0.321±0.036 kg gear-1 person-1 hour-1) and fish trap (0.0005±0.0002 kg gear-1 person-1 hour-1), respectively. Alternatively, the highest fish catch were recorded on April (21228±464.38 kg) and lowest on August (3855±138.21 kg). The fishermen identified a few noteworthy dangers to fish diversity, which should be addressed properly to enhance the fish biodiversity of Gorai River.

International journal of natural sciences, Jul 31, 2016

This study was conducted to investigate and compare the growth performance of four Tilapia strain... more This study was conducted to investigate and compare the growth performance of four Tilapia strains in hapa nursing with the aim to find out the best strain of tilapia. The research was conducted by four treatments with five replicates each. The tilapia fry were collected from, BFRI source from BFRI HQ, Mymensingh stocked in Treatment-1; unknown source from Hi-Tech Tilapia Hatchery Dagoanbhuiya, Feni in Treatment-2, Philipine strain from Green Field Tilapia Hatchery, Laxmipur in Treatment-3 and fry from Breeding Cohort, Sonar Bangla Hatchery, Bamna, Barguna in Treatment-4. The Individual stocking weight (g) of fry was average 0.01g. The fries were stocked in 12 hapa at same stocking density of 1200 fish/m 2. Each of the hapa was 2m × 1m × 1m size and fixed in an earthen ponds. Supplementary feed with 31.29% of protein level consisting of rice bran (25%), mustard oil cake (15%), wheat flour (30%) and fish meal (30%) was given at the rate of 40% of their body weight per day manually, four times a day at the beginning of the experimental period and reduced to 25% of their body weight and continued up to harvesting period. The results showed that fry of Treatment-4 strain was the best strain and had significantly (p < 0.05) higher final mean body weight (FMBW), mean body weight gain (MBWG), specific growth rate (SGR) (9.75%), gross yield (GY) (2.13) and Net yield (NY) (2.12) than the Treatment-1 , Treatment-2 strains and Treatemnt-3 strain. Treatment-4 strain had the fastest growth rate, whereas the lowest performing strain was that from Treatment-2. We also analyzed survival rate of the fish from stocking to harvest, survival rate was highest in Treatment-4 strain (80%) where lowest is Treatment-3. Treatment-4 stain also showed the best feed conversion ratio (FCR) 1.62 than others. Considering the overall performance it can be concluded that tilapia strain collected from Breeding Cohort source is best among the four strains. However, further research may still be needed to compare more strains from different water body to evaluate the genetic potential for Tilapia.

Journal of fisheries, Mar 1, 2023

The current study compared the length-weight relationships and condition factors in mono-and mixe... more The current study compared the length-weight relationships and condition factors in mono-and mixed-sex Nile tilapia (Oreochromis niloticus). The trial lasted for 91 days and included two treatments with five replications for each, all with the same stocking density. During the study period, 20 randomly selected fish individuals were measured and recorded from each cage every two weeks. The observed growth trend was allometric, with no significant difference in the mean exponential values (b), 2.696 and 2.65 for mono and mixed-sex tilapia respectively. There was a significant difference in final weight gain between monosex (171.58±7.39 g) and mixed-sex (149.09±4.14 g) tilapia. There was no significant difference in final length between monosex (19.80±0.42 cm) and mixed-sex (19.80±0.42 cm) tilapia. Moreover, the mean correlation coefficient (r 2) of both groups was positive. The Fulton condition factor (K) also varies from 0.700 to 1.000 (monosex) and 1.000 to 1.010 (mixed-sex). The relative condition factor (K n) for monosex and mixed-sex tilapia ranged from 1.96 to 2.222 and 2.092 to 2.35 respectively, indicated good aquaculture conditions. The present findings will attract fish farmers to mixed-sex tilapia culture by allowing them to lessen hormone administration and expected to boost national fish production through open water cage aquaculture.

Asian fisheries science, Dec 6, 2008

Aquaculture, Dec 1, 2011

A sustainable semi-intensive pond aquaculture technology including major carp species as 'cash-cr... more A sustainable semi-intensive pond aquaculture technology including major carp species as 'cash-crop' and small indigenous fish species (SIS) as food for the farmers' families is being optimized in Bangladesh. This is done through manipulations of the fish species combinations stocked, considering the ecological effects produced by bottom feeders on the pond bottom and filter feeders in the water column. The present paper presents results of experiments performed simultaneously in 64 farmers' fish ponds, located in 4 distant agro-ecological regions of Bangladesh. In each region each experiment involved 4 treatments, 4 replicates per treatment. The control polyculture was the traditional stocking of 33 rohu (Labeo rohita), 33 catla (Catla catla), and 34 common carp (Cyprinus carpio) per 100 m 2 , with the addition of 250 SIS and 3 silver carp (Hypophthalmichthys molitrix) per 100 m 2. In previous experiments this silver carp addition was found to have no effects on the other fish and on the environment, compared to the traditional stocking without silver carp. Interferences on the water column (Water treatment) were achieved changing the density of the herbivorous fish (reducing catla density to 24/100 m 2 and increasing silver carp to 12/100 m 2), and on the bottom (Bottom treatment) doing so on the benthophagous fish (replacing 10/100 m 2 common carp by mrigal). Both interferences were simultaneously carried out in the Water and Bottom treatment. Harvesting weight and biomass, growth rate, survival and yield of each species and total yield, food conversion ratio and income obtained in the different treatments and regions are presented and their interactions through the food web are discussed. Performing the same experiment in four distant regions of the country allowed observing if the effects of the Water column and/or Bottom interventions differ among regions, and accelerating the dissemination of the "cash-SIS" technology throughout the country. The manipulations performed did not affect the small fish mola, which reproduced and yielded equally well in all the polycultures. This allowed a continuous mola supply for consumption by the farmers' families throughout the culture season, and opened the option to consume or sell the larger amounts of mola gathered at final harvest. Manipulation of species composition proved to be a useful tool to affect the pond ecosystem towards improving fish yield and corresponding income. Just by substituting almost a third of the catla by silver carp increased total yield by 16%. When also almost a third of the common carp was substituted by mrigal, total yield increased a further 3%. In both cases selling the whole production increased income by 27%, which gives the farmer the option to keep part of the fish for family consumption.

To assess the culture potential of mola (Jlmblypharyngodon mala) along with carps in polyculture ... more To assess the culture potential of mola (Jlmblypharyngodon mala) along with carps in polyculture systems, an experiment consisted of three treatments each with five replications was conducted for 4 months in two villages of Parhatipur upazilla under Dinajpur district. In the first treatment (SS), catla, rohu, mrigal, grass carp, Thai punti, common carp and a higher density of silver carp (8 per 40m 2) were stocked. In the second trcaLment (SM), stocking density of silver carp was reduced to half and mola was added at a stocking density of 12,500/ha with all other fishes used in SS. In the third treatment (MlVl), no silver carp was stocked and mola was added at a stocking density of 25,000/ha with all other fishes used in SS. All treatments were subjected to the same regime of feed and fertilizers. The yields of large carps were 2035 kg/ha, 1757 kg/ha and 1326 kg/ha for treatments SS, SM and MM, respectively. Catla, grass carp and carpio showed better growth and production performance in presence of mola at a higher density, while rohu, Thai punti and mrigal showed better performance when stocking density of mola was relatively low. Mola yield was almost two times higher (184 kg/ha) in absence of silver carp (MM) than (62 kg/ha) in presence of silver carp (SM). The result showed that there was a significantly (p<O.Ol) lovver total fish production in treatment MM. But there were no significant difference in total production between treatment SS and SM.

Aquaculture Research, Jun 1, 2009

An on-farm trial was carried out from February to June 2006 to evaluate the growth and production... more An on-farm trial was carried out from February to June 2006 to evaluate the growth and production performance of catla (Catla catla) and tilapia (Oreochromis niloticus) with freshwater prawn (Macrobrachium rosenbergii) and mola (Amblypharyngodon mola) in farmer' s rice ¢elds. In all treatments, 20 000 mola ha À 1 and 20 000 prawn ha À 1 were stocked. Besides, stocking included 2500 catla ha À 1 in treatment-I, 2500 tilapia ha À 1 in treatment-II and catla and tilapia at 1250 ha À 1 each in treatment-III. Prawns were fed in the evening with pellets at a feeding rate of 3^8% body weight (initially 8% and gradually decreased to 3%). Catla and tilapia were fed in the morning with a paste of mustard oil cake and rice bran at a feeding rate of 3% body weight. Signi¢cantly higher combined production of ¢sh and prawn observed was 2142 kg ha À 1 in treatment-I. The bene¢t:cost ratio was found to be signi¢cantly higher in treatment-I than in treatment-II and there were no di¡erences between treatments I and III. From the production and economic point of view, treatment-I was found to be the best proposition for the rotational rice^¢sh culture systems.

Aquaculture International, Oct 28, 2016

Small indigenous species (SIS) of fish such as the mola carplet (Amblypharyngodon mola) are rich ... more Small indigenous species (SIS) of fish such as the mola carplet (Amblypharyngodon mola) are rich in nutrients, often containing high levels of zinc, iron, and vitamin A. Despite scientific and government efforts, culture of SIS for improved nutrition is not yet widespread. This paper investigates the contribution of the mola carplet, commonly referred to in Bangladesh as ''mola'' to household fish consumption, and the factors influencing productivity and income from carp-mola polyculture in southwest Bangladesh. In addition, we assess the effect of inclusion of mola into carp polyculture ponds on the inputs required to culture fish in homestead ponds. Carp-mola polyculture farmers (n = 344) and carp-only polyculture farmers (n = 513, as controls) were surveyed in May 2013. Mola broodstock were stocked in 4881 homestead ponds, at an average rate of 25 kg ha-1. The results indicated that pond area, water color (a proxy of phytoplankton abundance) and inorganic fertilizer (primarily urea and TSP) significantly influence mola production. Smaller ponds proved to have higher productivity than larger ponds. Production and profitability of carp-mola polyculture system are significantly higher (P \ 0.1) than carp-only polyculture systems. Mola also contributed to household fish consumption, with 47 % of mola produced in homestead ponds consumed by household members. The results suggest scope for wider dissemination and impact of mola production technology. Such dissemination might involve closer collaboration among research, governmental, and non-governmental organizations, involving lead farmer selection, farmer-to-farmer visits and result demonstrations and wider communication of the positive outcomes of culturing mola.

Aquaculture Research, Mar 1, 2008

The e¡ects of di¡erent stocking densities of freshwater prawn (Macrobrachium rosenbergii) on its ... more The e¡ects of di¡erent stocking densities of freshwater prawn (Macrobrachium rosenbergii) on its growth and production in relation to the presence of small self-recruiting species mola (Amblypharyngodon mola) were investigated in modi¢ed rice ¢elds after rice harvest at Mymensingh, Bangladesh. Keeping the stocking density of mola ¢xed at 20 000 ha À1 in each treatment, four densities of freshwater prawn (treatments) were maintained:10 000,15000, 20 000 and 25000 ha À1 respectively. The rice plots were limed (CaCO 3) and fertilized with urea, triple super phosphate and cowdung regularly. The prawns were fed daily with commercial pellets.Water quality parameters such as temperature, dissolved oxygen, transparency, pH, total alkalinity, inorganic nitrogen (nitrate, nitrite and total ammonia), chlorophyll a and orthophosphate were determined fortnightly. Numerical analysis of plankton communities was performed monthly. All water quality parameters were found to be within the suitable range for freshwater prawn culture, except high temperature, in the peak summer months. There was a homogenous abundance of plankton communities in all treatments throughout the experimental period. Mola started to breed in the second month of the original stocking with partial harvesting after the second month and continued until the ¢nal harvest. The total production of mola ranged between 124 and 152 kg ha À1 during the 4-month culture period. The average prawn survival ranged from 49% to 57% without any signi¢cant di¡erence among treatments. Freshwater prawn production ranged from 294 to 596 kg ha À1 with signi¢cantly higher production in the treatment where 20 000 ha À1 freshwater prawn were stocked. This treatment also resulted in a higher net pro¢t margin (74%), indicating that stocking at a combination of 20 000 ha À1 freshwater prawn and 20 000 ha À1 mola could be the optimum proposition for prawn^mola culture in modi¢ed rain-fed rice ¢elds after rice cultivation.

Asian fisheries science, Jul 2, 2012

A study was conducted to evaluate the effects of stocking density of all-male freshwater prawn Ma... more A study was conducted to evaluate the effects of stocking density of all-male freshwater prawn Macrobrachium rosenbergii (De Man, 1879) on water quality, production and economic return in polyculture ponds. Trials involving three stocking densities of all-male prawn viz., 15,000, 20,000 and 25,000 ha-1 were carried out in replicates, combined in polyculture with fixed densities of silver carp, catla and small fish mola at 1,500, 1,000 and 20,000 ha-1 , respectively. Commercial prawn feed and fertilisers were applied routinely to all ponds. Blue-clawed males were harvested periodically at 15-day intervals over a 5-month culture cycle before final harvest. Differences in prawn density (treatments) did not significantly (P>0.05) affect any water quality parameters. Mean weight of prawn at harvest decreased significantly (P<0.05) with increasing stocking density. Net production of prawns however, was significantly higher at prawn densities of 25,000 and 20,000 ha-1 (661 kg. and 640 kg. ha-1 , respectively) compared with 15,000 ha-1 (535 kg. ha-1). Silver carp and catla production did not differ significantly among density treatments, while production of mola was higher at 20,000 prawn. ha-1. This treatment also resulted in higher net production of all species combined (1,688 kg. ha-1) as well as the highest return (US$ 2,597 ha-1).

International Journal of Fisheries and Aquatic Studies, May 1, 2022

Bio-floc technology ensures increased aquaculture intensification and the most efficient use of l... more Bio-floc technology ensures increased aquaculture intensification and the most efficient use of land, water, and feed resources, all while minimizing environmental impact. Bangladeshi farmers hope that Biofloc technology will provide them with a new horizon in the face of massive climate change. With the introduction of bioflock technology, the cost of fish production for farmers is falling. With the filling of rivers, canals, and beels, the number of houses and factories in Bangladesh is expanding. With all of this in mind, biofloc technology is timeless and sustainable for high-density fish farming in a small area, ensuring safe net food and increased production. As the fishing industry has evolved, more innovative and efficient methods of raising and harvesting fish have been adopted to meet the demands. The Biofloc technology, for example, was developed to cope with wastewater management, sustain biochemical cycles, and preserve aquatic life's nutritional levels. Within a short period of time, this approach has experienced tremendous growth. It is now widely utilized to assure the continued growth of aquatic life and the fishing sector. Its main goal is to convert the hazardous waste material produced in aquatic environments into protein-rich food for the creatures that live there.

Malaysian applied biology, Dec 31, 2021

The study was aimed to investigate the current status and threats of fisheries resources in the K... more The study was aimed to investigate the current status and threats of fisheries resources in the Kura River, Bangladesh. Monthly fish catch surveys were carried out from December 2015 to November 2016 in four catchment areas at Hasinarghat, Kandir-dor, Pulertol, and Barartok. In addition, questionnaire interviews and focus group discussions (FGD) were done to clarify perceptions about the Kura River fishery status. A total of 59 fish species from 22 families were documented and of which 27% were threatened. The values of diversity (H), richness (D), and evenness (J') were calculated at 3.599, 4.345, and 0.921 respectively. The highest catch volume was recorded 19800±7722.71 kg in November 2016 at the Kandirdor and the lowest 225±110.65 kg in March 2016 at the Barartok (p<0.05). The upstream blockage (man-made dam) in the Kura River was identified as the main cause of fish habitat change, decrease fish biodiversity, and production of this River. Therefore, the findings of this study exposed that the conservation of fish has become urgent. In this regard, the baseline scenario of the Kura River biodiversity and threats will help to make awareness to take necessary conservation strategy as well as the need for further in-depth study.

Sustainability, Mar 15, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

The compatibility of Dhela (Osteobrama cotio) (Hamilton) with major carps was studied in grow-out... more The compatibility of Dhela (Osteobrama cotio) (Hamilton) with major carps was studied in grow-out carp polyculture system for a period of 138 days in a set of six earthen ponds varied from 4 to 14 decimal days from 16 July 2013 to 30 November 2013 at Rayghar village of Golabgonj upazilla under Sylhet district, Bangladesh. Two different species combinations evaluated were T : catla (Catla catla Hamilton.), rohu 1 (Labeo rohita Hamilton), mrigal (Cirrhinus mrigala Hamilton) and dhela at 1:0.67:0.67:2; and T : catla, rohu and 2 mrigal at 1:0.67:0.67 at combined density of 16055 and 8645 fingerlings/ha respectively. While survival levels of the carps did not differ significantly in treatments (P>0.05), silver carp recorded highest survival levels (94-96%) followed by olive barb (87-90%), mrigal (72-74%), rohu (72-73%) and catla (67-69%). All the treatments were subjected to same regime of feed and fertilizers. Yield of dhela was found 37.45 kg ha in treatment T. 1 1 Production of dhela was very low because it did not able to take part breeding due to late stocking. Survival of dhela observed 83.56%. Total production of fish obtained in this experiment was 768.09 kg ha and 1 806.64 kg ha in treatment T and T , respectively. There were no significant differences in total production 1 1 2 between the treatments. Water parameter analysis showed that mean values of water temperature, transparency and dissolved oxygen were not significantly different among the treatments except pH. The total revenues per ha pond during study period were Tk. 94520 and Tk. 96720 in treatments T and T respectively. The net 1 2, benefits from treatment T and T were Tk.44605 and Tk. 57515, respectively. However, from the result of the 1 2 experiment it can be concluded that dhela may be one of the good candidate species for carp plolyculture system considering its high nutritional value and having no negative impacts on the growth of carp species.

A study was conducted 11:0 ascertain the existing farm water, effluent and feed quality of select... more A study was conducted 11:0 ascertain the existing farm water, effluent and feed quality of selected giant freshwater prawn farms from major prawn farming areas (Bagerhat Sadar, NoakhaH Sadar and Mymensingh) of Bangladesh during July to November 2005. Water quality parameters such as the mean values of dissolved 0 2 , alkalinity, N0 2-N, P0 4-P and NH 3-N did not show any significandy differences among the farming areas. Whereas significant differences (p < 0.05) were observed in the mean values of temperature, secchi disc visibility, pH and chlorophyll a. However, all the water quality parameters in the farming areas were within the suitable range for prawn cuhure. There was no significant variation in nutrients concentration of discharged effluent among the prawn farming areas. AH of the nutrients measured in effluent water were within the acceptable range and did not seem to pose a direct threat to the recipient environment. The analysed crude protein contents of commercial CP, Quality and Saudi-Bangla prawn feeds were 31.84%, 27.21% and 28.97%, respectively, whereas all analysed farm made feeds were less than 25%. The other nutrients of prawn feeds varied largely with the source of feeds and ingredients used to prepare feed. The annual yield of prawn varied from 320.4 to 512.6 kg ha• 1 (mean 412.3 kglha) depending on the management system.

Aquaculture Research, Mar 1, 2010

The e¡ects of selective harvesting (SH) and claw ablation (CA) of blue-clawed (BC) prawns on an a... more The e¡ects of selective harvesting (SH) and claw ablation (CA) of blue-clawed (BC) prawns on an all-male freshwater prawn^¢n¢sh polyculture system were compared with control (Co) in quadruplicate. Ponds were stocked with all-male freshwater prawn Macrobrachium rosenbergii, silver carp Hypophthalmichthys molitrix, catla Catla catla and mola Amblypharyngodon mola at 12000, 2000, 500 and 20 000 ha À 1 respectively. Prawns were fed with pelleted feed. Ponds were fertilized regularly with urea, triple super phosphate and cow-dung. SH of BC prawns in treatment SH and CA in treatment CA started on the 60th day during a 137-day culture and continued at 15-day intervals until the ¢nal harvest. Water quality parameters and plankton abundance did not vary signi¢cantly (P40.05) among the treatments. Treatment SH resulted in a higher (Po0.05) net production of freshwater prawn (437 kg ha À 1), with better survival and mean weight, followed by CA (354 kg ha À 1) and Co (322 kg ha À 1). The combined net production of prawn plus ¢n¢sh was also higher in SH (1244 kg ha À 1) as compared with CA (1161kg ha À 1) and Co (1137 kg ha À 1), although the ¢n¢sh production did not di¡er signi¢cantly. The periodic SH of BC prawns showed a better economic return with a BCR of 1.71.