Indices and fecundity of a threatened freshwater catfish Mystus montanus

Fecundity of threatened catfish Mystus montanus was estimated from a collection of gravid females, which ranged from 290 to 27,972 according to body length and weight. The relationship between fecundity and BL, BW, GL and GW was analyzed by linear regression, which showed both positive and negative correlation. Gonado-somatic index (GSI), hepato-somatic index (HSI) and spleen-somatic index (SSI) ranged from 0.135 to 21.28, 0.358 to 21.33 and 0.126 to 1.08 in females and the corresponding values for males were 0.17 to 10.68, 0.619 to 3.25 and 1.25 to 2.33 respectively.

Labels or fables? The myth of sustainability: a collection of articles from SAMUDRA Report

Labels or Fables? The Myth of Sustainability examines the costs of certification of global fisheries and how it is allegedly biased towards industrial-scale fisheries. This dossier is a compilation of articles from Samudra Report dealing with the issue of ecolabelling in fisheries.

Size related feeding patterns and electivity indices of silver barb (Barbodes gonionotus Bleeker) from a pond, Bangladesh

The feeding patterns with respect to quality and quantity of food of silver barb, Barbodes gonionotus varied with their size and development. The results indicated that the fish in the size group I (7-25 mm TL) were fairly omnivore with particular liking for rotifera, green and blue-green algae while the size group II (25.1-44 mm TL) and III (44.1-55 mm TL) were omnivore with higher tendency of feeding on debris, aquatic plants, green algae, blue-green algae and rotifera. However, the fish of the size group IV (55.1-80 mm TL) were found to be herbivore with feeding preference for aquatic plants, green and blue-green algae. In all the size groups, debris was the most dominant food item. Feeding preference of the fish showed clear ontogenetic shift. The electivity indices revealed that the fish were selective feeder.

Challenges to effective fishing and preferred fishing gear in a hydrodynamic freshwater system

Challenges to fishing and preferred gear of multiple used Lake, whose water depth is controlled by opening of its dam gate were investigated. Geographic survey, interview and focused group discussion of fishermen were used to assess factors influencing effectiveness of fishing and the preferred gear of Asejire Lake. Water usage (s) such as frequency of Complete and Partial Opening of Dams Gate (CODG and PODG) were investigated as indices for hydrodynamic condition. Response during focused group discussion with about 33% of fishermen of the Lake were obtained on sources of disturbance to effective fishing (SDEF), most effective gear (MEG)- least environmentally perturbed gear, comparability of catch structure of preferred gear to conventional gear and sustainability of superiority of preferred gears in situations outside hydrodynamic condition (SSPPG). The PODG occurred 1-7times/Month-dry season, 15-18times/Month-wet season; CODG occurred 1-2times/Month in both season; Interval of CODG was 3-17 and 5-12days (dry and wet season). It affected set-net and catch. The SDEF were gear availability, weather condition, dam’s gate opening, religion activities and Health of fisher-folks. 50% respondents accepted opening of dams gate as most important disturbance while religion was least (5% respondents accepted). 60% respondents accepted traps as MEG being the least affected while 75% respondents accepted Gura cage trap as the MEG among traps.90% respondents accepted that among traps, its catch structure was closest (comparable) to conventional gear. However, 75% respondents rejected SSPPG. Opening of dams’ gate creates hydrodynamic condition and it affects fishing. Gura trap was preferred for fishing hydrodynamic condition.

Diversity indices of selected macrobenthos in Karanja Creek (District-Raigad), Maharashtra, west coast of India

The diversity indices can be used as a good measure for studying the effect of industrial pollution because industrial wastes and sewage almost always reduce the diversity of natural systems into which they are discharged. A measurement of diversity often provides a better index of pollution than a direct measurement of pollutants. The assessment of macrobenthos diversity with respect to diversity indices reflects the marine population and habitat disturbance, and also serves as an important indicator of environmental conditions. The present study was designed to investigate the diversity indices of selected macrobenthos at two ecologically distinct locations on the Karanja creek (District - Raigad), Maharashtra, west coast of India. Results on various diversity indices like Index of Frequency (F) or Importance Probability (Pi), Index of Dominance (c), Rarity Index (R), Shannon's Index of General Diversity (H¹) Margaf’s Richness Index (R sub(1)) and Evenness Index (e) did not vary significantly. This demonstrates that at present, Karanja creek harbours varied forms of macrobenthic community showing no effect of human disturbance, but in future, measures must be taken for the protection and conservation of macrobenthic community of the creek.

Disease problems in shrimp sector in Khulna district of Bangladesh: a question of sustainability

Disease is the main restraining factor for the development of shrimp sector in Bangladesh. Both brackish water shrimp bagda (Penaeus monodon) and freshwater prawn golda, (Macrobrachium rosenbergii) farming in Bangladesh have been facing disease problem. A study on disease outbreak in both brackish water and freshwater small-scale shrimp farms (gher) in Khulna district was carried out through interviewing randomly selected 3-5% of shrimp farmers with a structured questionnaire during March to December, 2002. The study showed that 97% bagda farming ghers and 80% golda farming ghers were affected by disease. White spot disease was the severe disease for bagda, whereas, antenna rot was the main disease for freshwater prawn. Change of water and liming were carried out as control measures of disease for bagda shrimp farming, while it was only liming for golda farming. A small number of shrimp farmers (15%) used chemicals for treatment of shrimp diseases. Development of suitable farming technology to prevent disease contamination and innovation of proper treatments for diseases are required to overcome the disease problems for sustainable shrimp farming in Bangladesh.

A bioeconomic analysis of sustainability of marine fish production in Kerala

The study has been undertaken in Kerala State in India with an overall objective of analyzing the bio-economic conditions of commercially exploited marine fishes for assessing their sustainability in the context of existing management practices. Maximum sustainable yield, maximum economic yield and open access levels of yield and effort were analyzed using Gompertz-Fox growth model. The study concluded that the fishing effort exceeded the economically optimal levels and there is unnecessary wastage of money, manpower and fuel in the fishing industry. The study stressed the urgent need for capture fisheries management in the State which at present follows an open access fishery where regulations exist only in the form of seasonal closure in the monsoon season.

Evaluation of some biological indices and population dynamic of "Saurida tumbil" in the northern Persian Gulf and Oman Sea

The Great lizardfish is one of the commercial demersal fishes in the Persian Gulf and Oman Sea. In this study the food preference index (FPI), Fullness index (FI) and stomach contents of Saurida tumbil were evaluated to assess the quantity and kind of food which this species consumes in the study area. The samples were collected monthly from commercial bottom trawl fisheries in main fishing grounds of eastern Strait of Hormuz. A total of 346 specimens were collected during years 2009-2010 of which 269 specimens were female and 77 specimens were male. The minimum and maximum total length were 161 and 590 mm, respectively with the highest frequency in length group of 350-370mm. Results showed that 20.9% of stomachs were full, 18.9% were semi-full and 60.2% were empty. The main stomach contents (FPI=80.2%) were fishes and minor stomach contents (FPI=25.7%) were crustacean (Specially crab and shrimp) and cephalopods were found as random food. The minimum and maximum FIs were 2.5 and 42.5 in December and September respectively; and the overall CV was 60.2. The results indicate that this fish is a relatively frugal species which consumes fishes as main food and there is no difference in feeding of male and female.

Effect of thawing methods on the chemical, biochemical, microbiological and sensory indices of Caspian Sea kutum (Rutilus frisii kutum) and rainbow trout (Oncorhynchus mykiss)

Effects of different thawing method i.e. in a refrigerator, in water, at air ambient temperature and in a microwave oven on proximate, chemical (PV, TBA, FFA, TVB-N, SSP, FA), biochemical (pH, WHC,ThL), microbial (total viable, psychrotrophic, coliform, Shewanella and yeast-mould count) and sensory analysis were carried out on frozen whole Caspian sea Kutum (Rutilus frisii kutum) and Rainbow trout (Oncorhynchus mykiss) carcasses. The values of ash, protein, SSP, WHC, PUFA, PUFA/SFA. EPA+DHA/C16:0, pH, and microbial count of thawed samples decreased significantly while fat, PV, TBA, FFA, TVB-N, SFA and MUFA increased compared to the fresh fish (unfrozen) as control samples. Also, sensory evaluation all of thawed samples showed a significant (p<0.05) quality loss compared to the fresh fish as control samples. The lowest chemical and biochemical values as well as microbial growth were determined in water thawed samples. Therefore, based on this study thawing in water is most suitable for frozen whole rainbow trout.

A comparative study on effects of Immunoster and Immunowall as immunostimulants on some hematological, biochemical and growth indices of farmed great sturgeon juveniles (Huso huso)

Prebiotics are non-digestible food ingredients that profitably affect the host by selectively stimulating the growth and /or activation of one or a limited number of bacteria in the intestine that can enhance host health status. Immunoster (IS) and Immunowall (IW) are prebiotics and immunostimulants derived from the outer cell wall of brewers yeast, Saccharomyces cerevisiae. These substances contain MOS and �-glucans. After a four-week acclimatization period to rearing conditions and basal diet, 450 farmed great sturgeon juveniles weighing 95.58 ± 9.38 g were randomly distributed into 15 fiberglass tanks (2 × 2 × 0.53 m) in five treatments (Control, IS 1%, IW 1%, IS 3%, and IW 3%) in three replicates (completely randomized design) and kept at a density of 30 fish per tank for a period of 8 weeks at water temperature 20.55 ± 5.11ºC, dissolved oxygen 6.73 ± 0.35 mg L-1 and pH 7.92 ± 0.09. IS and IW were added at two levels of 1% and 3% to the basal diet in place of cellulose, except the control. At the beginning, in the middle and at the end of the trial, carcass analysis was done to determine the moisture, protein, fat, ash, and total carbohydrate. Also, blood samples were collected to measure hematological, biochemical and immune indices. At the end of the trial, final weight, final length, body weight increase (BWI), specific growth rate (SGR), average daily growth (ADG), protein efficiency ratio (PER), feed conversion ratio (FCR), and condition factor (CF) in fish fed on IS and IW in both levels 1% and 3% showed some differences. These differences were significant in IS 3% and IW 1% and 3% compared with the control (P<0.05). HSI showed no significant difference (P>0.05) and survival rate was 100% in all treatments. Crude protein of carcass in fish fed on IS and IW at 1% and 3% showed an increase in comparison with the control. There was significant difference between IS 3% and the control in crude protein of carcass (P<0.05). Fish fed on IS and IW at 1% and 3% showed various results in hematological and biochemical factors. It was observed significant difference in MCV between IW 1% and IS 3% compared with the control (P<0.05). Although there was an increase in values of hematocrit, hemoglobin (except IS 1%), WBC (except IW 3%), MCH, neutrophil, total protein, albumin (except IS 3%), K+, and lysozyme in fish fed on IS and IW compared with the control, it was no significant (P>0.05). The maximum count of WBC and the highest value of Ca2+ were seen in IW 1%. The maximum count of lymphocyte, the highest values of total protein, albumin and IgM were recorded in IW 3%. IS 1% had the maximum count of neutrophil and the highest concentration of lysozyme. Based on obtained results, it can be declared that IS and IW at two levels of 1% and 3% can enhance growth performance and feed efficiency and also improve some hematological, biochemical, and immune indices in farmed great sturgeon juveniles.

Study on the sustainability of FPC produced from Kilka (Clupeonella engrauliformis, C. grimmi and C. cultriventris) in two vacuum packaging and modified atmosphere packaging at different environmental factors

Fish protein concentrate (FPC) is a healthy, sustainable and high nutritive product which sanitized produced from fishes in which, protein and other nutrients are more concentrated than in fresh fishes. The aim of this research is to study on the sustainability of FPC produced from Kilka (Clupeonella engrauliformis , C. grimmi and C. cultriventris) in two Vaccum Packaging and Modified Atmosphere Packaging at different environmental factors during six months. In our study the analysis of FPC protein showed 91.2%, lipid: 0.5%, ash: 3.6%, moisture: 2.3%, Total Volatile Nitrogen: 10 ml/100gr and peroxide: 5meq/kg. Amino acids and fatty acids were also determined. Bacteria and Fungi were lower than 1000 colony. Samples are kept in different condition of temperature (5, 20 and 35 degree centigrade), humidity (25, 40 and 90 percent) and light and dark environment in six month. Lipid rate in FPC after 6 months in VP and MAP (60% C02, 30 % N2 and 10% O2), packages was decreased but was not significant (P>0.05). It was also detected that increase temperature lead to more decrease in lipid content. Protein rate of FPC was decreased from 91.2% to 73.6% during six months at 35°C in VP Package and from 91.2% to 69.4% in MAP package. These changes were significant (P<0.05). TVN and PV rate in FPC after 6 months in VP and MAP packages was increased but was significant (P<0.05). Amino acids and fatty acids were also determined. But more changes in MAP packages was detected.

Study on effects of extracted probiotics from microbial flora of digestive system on growth indices in beluga (Huso huso) and Persian sturgeon (Acipenser persicus)

Isolation of Lactic Acid Bacteria (LAB) was carried out from gastro intestinal tract of beluga and Persian sturgeon at international sturgeon research institute and PCR has been used for bacteria Identification. Two species of LAB including Enterococcus seriolicida and Leuconostoc mesenteroides were isolated from Gastrointestinal tract (GI) of persian sturgeon in this study and the counts of Leu. mesenteroides (4.63×102 CFU/gr of GI) was significantly higher than other species. Lactobacillus curvatus, Lactococcus raffinolactis, Lactococcus lactis and Streptococcus sp. were also isolated from GI of beluga and maximum counts was belonged to Lb. curvatus (4.63×102 CFU/gr of GI) in this species. Dominant species were lyophilized and adding to the water since start of mix feeding of sturgeon with different counts including 2×109, 5×109 and 9×109 CFU/gr of live food, 4 times a day. The results revealed that the maximum and minimum growth rate and protease, amylase, and lipase activity in beluga was gained by using of Lb. curvatus with total viable count of 9×10 9 CFU/gr of live food and Leu. mesenteroides with total viable count of 9×109 CFU/gr of live food. According to the results of this study, the maximum and minimum growth rate and protease, amylase, and lipase activity in Persian sturgeon was gained by using of Leu. mesenteroides with total viable count of 2×10 9 CFU/gr of live food and Lb. curvatus with total viable count of 9×109 CFU/gr of live food. Histological study showed that gastrointestinal development was same during larva rearing in control and other treatments but the size of liver was bigger in treatments that received nonspecific LAB in both species. According to the results, positive effects of using dominant specific LAB bacteria for larviculture of sturgeon has been proved in this study.

Sustainability in aquaculture

Sustainable aquaculture in Asia is discussed, considering in particular the loss of mangroves associated with the rapid increase in production of cultured shrimp. Southeast Asia's development and population growth brought non-sustainable exploitation of its coastline; the destruction has increased through the years as development proceeded and the international markets entered the scenario. An outline is given of the current status of mangroves in some Asian countries. Some worldwide remedies for sustainable aquaculture are described.