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Research Article
Feb 15, 2013
Condition Index and Neutral Red Assay Response of Cultured Mytilus edulis L. Stored in a Wet Holdin ... g Facility during Winter and Spring in Northeastern Newfoundland
In order to determine the effects of extended wet-holding on cultured blue mussels under ambient conditions during the winter and spring in Newfoundland, we investigated physiological stress response using the Neutral Red Assay, change in dry and wet weight and in overall condition based on the dry tissue weight/dry shell weight ratio and the dry tissue weight/wet tissue weight ratio of animals held for up to three months in a commercial holding facility and compared with field controls. During the winter season, dry weight and condition of mussels in the holding facility increased significantly over the three month period when compared with samples from the field. Spring-held mussels were observed to lose dry weight and condition in holding as compared with field controls. The Neutral Red Assay indicated an observed but not statistically significant change in physiological stress response for mussels held during the winter season. No observed change was noted for field controls. During the spring no overall change was noted in Neutral Red response for held or field control samples Dry weight and condition analysis indicated that the winter season was the most stable for long term holding of harvested mussels. Overall analysis of lysosomal neutral red retention time did not reveal a statistically significant response for mussels held during winter or spring suggesting that low temperatures may affect the haemocyte lysosomal response to Neutral Red retention. Based on the observed change in condition and dry weight across season, we recommend that mussels can be held for at least two months during the winter season and at a limit of one month for spring (especially late spring i.e. May and June) before a significant loss in condition and potential quality is observed.
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Research Article
Jan 09, 2013
Species richness and floral diversity around ‘Teesta Barrage Project’ in Jalpaiguri district of West ... West Bengal, India with emphasis on invasive plants and indigenous uses
An investigation was carried out in Gajoldoba beels, Saraswatipur forest, tea gardens and village areas around ‘Teesta Barrage Project’ (TBP) to document floral diversity and their uses by local people during 2011-2012. Around 81 plant species distributed in 75 genera, along with 4 fern species, all under 45 families (dicot - 33, monocot - 08, fern - 04) have been documented. Family Fabaceae dominated with highest number (12 taxa) of plant species, and was followed by monocot family Poaceae with 7 taxa. Plant species showed marked variations in frequency, density and abundance in 200 randomly laid quadrat studies. Among the flowering plants, Lantana camara, Mikania indica, Parthenium hysterophorus, Ageratum conyzoides, and Cynodon dactylon exhibited aggressive invasions. About 36 (44.44%) plant species were used by local people for diverse medicinal purposes. The study revealed presence of rich biodiversity, local traditional knowledge on herbal medicine and resource utilization in TBP area which need urgent conservation.
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Research Article
Jan 02, 2013
A Comparison of A Creel Census to Modeled Access-Point Creel Surveys on Two Small Lakes Managed as ... Put-and-Take Rainbow Trout Fisheries
Access-point creel surveys are assumed to represent actual angler harvest, pressure, and other parameters. A full creel census was conducted on two small lakes managed as put and-take Rainbow Trout (Oncorhynchus mykiss) fisheries to evaluate this assumption. Modeled results based on standard methods from full (40 h/week), one-half (20 h/week), and one-third (12 h/week) surveys, were compared to actual census values. The confidence intervals for angling pressure in all survey scenarios included the actual census values, with the exception of the full survey in one lake. Confidence intervals for total catch also included the census values, except for the full and onethird survey in one lake. In all cases, both Rainbow Trout catch and harvest point estimates were not significantly different among any of the scenarios and census. Census values for party size were not included in the confidence intervals in the one-third surveys at both lakes, and the one-half survey at one lake. Trip length confidence intervals included the actual census value only in the full survey for one lake; all other point estimates of trip length in the other survey scenarios were significantly different from the census values. In general, confidence limits increased as the simulated survey efforts decreased. Using standard access-point creel survey methods, managers of small water bodies stocked with catchable trout should be able to achieve relatively reliable creel survey estimates of angling pressure, catch, and harvest with considerably less effort than a full survey.
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Research Article
Dec 06, 2012
Impact of Formulated Protein Diets on Growth of the Indian Major Carp, Labeo rohita (Hamilton)
Fresh water aquaculture in India is mainly carp-based and accounts for a considerable proportion of total aquaculture production. Feeding constitutes a major factor in fish culture since the fish obtain the maximum nutritional requirement through the food they consume. Protein forms one of the main components of fish feed and hence formulation of feeds that contain high amount of protein using cost-effective natural ingredients is very essential to achieve efficient production from fish culture. Labeo rohita is an extensively studied fish and contributes to a considerable proportion of fish production in India. In the present investigation, four different kinds of fish feed (using groundnut cake, azolla, rice bran and tapioca powder) were formulated with varying protein concentrations (30%, 35%, 40% and 45%) and given to L. rohita to assess the impact of the protein diet on its growth and bioenergetic parameters. The fish were fed with the formulated feed at a rate of 4% of their body weight for a period of 60 days. It was observed that the fish fed with formulated feed containing 40% protein content showed better growth results and improvement in bioenergetic parameters, compared to the other three feeds.
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Research Article
Oct 16, 2012
Effect of Different Salinity and Ration Levels on Growth Performance and Nutritive Physiology of M ... ilkfish, Chanos chanos (Forsskal) – Field and Laboratory Studies
To investigate the effect of inland groundwater salinity, and two ration levels on growth performance and nutrition physiology in milkfish, Chanos chanos, two experiments (Experiment 1 and 2) were conducted. In the first experiment (Expt. 1), a 100-day monoculture of Chanos chanos at two different salinities (10 and 25‰) was carried out in ponds and the fish were fed on two different (4% and 6% BW d -1 ) ration levels. Irrespective of the salinity treatment, low ration favored high growth in fish grown at 25 ppt salinity. Carcass composition revealed high accumulation of protein, fat, energy and phosphorus in fish fed at low ration level and maintained at 25 ppt salinity. Irrespective of the salinity treatment, DO, BOD, pH and nutrients remained significantly (P<0.05) higher in ponds where the fish were fed at low ration level. Multivariate analysis revealed a significant positive correlation of nutrients and productivity indicating parameters with fish weight gain. The second experiment (Expt. 2) was conducted under laboratory conditions and the milkfish fry were exposed to five different salinity levels (10.0, 15.0, 20.0, 25.0 and 30.0 ‰) for 100 days. A control in fresh water (0.0 ppt) was also maintained. Irrespective of the salinity treatment, significantly (P<0.05) high growth, feed conversion efficiency and intestinal enzyme activity were observed in fish maintained at low (4%) ration level. Carcass composition, muscle and liver glycogen levels, muscle protein, viscero-somatic index (VSI) and hepato-somatic index (HSI) values were also significantly (P<0.05) affected not only by the salinity treatment but also by the ration level. Studies indicated that low ration level and high salinity favored high growth in milkfish
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Research Article
Aug 06, 2012
Some Haematological Changes of Zander (Sander lucioperca) In Relation to Age and Its Relationship ... with Parasitic Infection
The blood parameters of Sander (S.) lucioperca were investigated among different age classes (2, 3, 4 and 5 year old). Also, alterations of haematological parameters in relation to parasitic infection were tested. The red blood cell (RBC), white blood cell (WBC), hematocrit (Ht), hemoglobin concentration (Hb), mean corpuscular volume (MCV), mean corpuscular hemogbobin (MCH), mean corpuscular hemoglobin concentration (MCHC), lymphocyte, neutrophil, monocyte and myelocyte were measured. No haematological parameters showed significant differences (P > 0.05) among age classes. The values of Ht, Hb, neutrophil and monocyte were higher in 4 year compared to other ages. The results showed that MCH, lymphocyte and myelocyte increased with the age. Significant differences were detected for the lymphocytes and neutrophils (infested versus non-infested by Eustrongylides excises and Dactylogyrus sp) respectively. No differences were found with regard to other haematological parameters of infested fish. Results from this study suggest that age has some degree of influence on the blood parameters of S. lucioperca.
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Research Article
Aug 05, 2012
Reproductive Biology of the Indian Oil Sardine Sardinella longiceps From Al-Seeb Waters off Oman
The objective of this study is to examine the reproductive biology of the Omani-Indian oil sardine Sardinella longiceps from AlSeeb area off the Omani waters. During the period January 2004–December 2008, a total of 1592 sardines were sampled. The lengths of the sampled fish ranged from 11.9 to 22 cm with a mean length of 16.5 ± 1.84 cm and modal length of 15.5 cm. Their weights ranged from 14 to 94.6 g with a mean weight of 42.43 ±15.19 g and modal weight of 43.7 g. The length–weight relationship equations analyzed for the combined sex, female, and male sardines were 2.99 W 0.009 L , 2.94 W 0.011L , and 2.94 W 0.001L , respectively. The length at 50% maturity for combined sex, female, and male sardines was 16.35, 16.46, and 16.28 cm, respectively. During the study, the Omani sardines were observed to spawn in October, June, and July, September, June, and January and September during the years 2004, 2005, 2006, 2007, and 2008, respectively. During the sampling period, the relative condition factor Kn varied from one year to another and ranged from 0.36 to 1.46 with a mean of 0.9 ± 0.08. An overall mean sex ratio of 0.68 ± 0.02 proved to be significantly different from the expected theoretical sex ratio of 0.5 ( 2 = 200; df = 1; P 0.05).
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Research Article
Jul 23, 2012
Survival Rate and Development Period of the Larvae of Portunus pelagicus (Decapoda, Brachyura, Por ... tunidae) In Relation to Temperature and Salinity
Berried females of Portunus pelagicus (Blue swimmer crab) were collected from the wild and the zoea 1 obtained from a single berry were stocked in 200 litre tanks at the rate of 25 numbers/mL. In order to study the independent effects of temperature and salinity, the larvae were reared in three different temperatures (26°C, 28°C and 30°C) at a fixed salinity of 35 ppt and in three different salinities (25 ppt, 30 ppt and 35 ppt) at a fixed temperature of 28°C. Feeding was carried out with microalgae, rotifers, moina and formulated shrimp feed, which varied with stage. The survival rates at each stage in all the trials were assessed by random sampling. The most ideal temperature and salinity among those studied were calculated in relation to the overall survival rate and larval development period. The data pertaining to both temperature and salinity manipulated investigations were found to be significant (P < 0.01) when subjected to one-way ANOVA. Among the tested temperatures, the highest average survival (14.12 0.31%) and the lowest average development period (14.67 days) were obtained at 30 ± 0.1°C. Among the salinity values tested, the highest mean survival rate (06.89 ± 0.06%) and the lowest average development period (14.33 days) were obtained at 35 ppt.
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Research Article
May 18, 2012
Population Dynamics and Management of Goldlined Seabream Rhabdosargus sarba (Sparidae) from the Om ... an Coast of Arabian Sea
Rhabdosargus sarba is one of the most important coastal demersal species inhabiting Omani waters. An estimate of the age and growth of R. sarba ranging from 15 to 43.2 cm total length collected from the Omani waters is made by examining the growth increment of their whole otoliths. The growth rings showed that R. sarba rarely attain more than six years. The von Bertalanffy growth parameters were K = 0.33 yr-1 , L = 46.97 cm and to = -0.83 yr. The mean total mortality coefficient "Z" estimated by two different methods was 1.8 yr-1 . The geometric mean of natural mortality coefficient "M" was 0.6 yr-1 . Exploitation rate "E" was computed as 0.67, while the length at first capture was 22.9 cm. The yield per recruit analysis showed that the stock of R. sarba in the Arabian Sea is overexploited and the exploitation rate should be reduced by about 47% to maintain a sufficient stock biomass for spawning and recruitment as well as the length at first capture should be raised to about 30 cm.
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Research Article
May 17, 2012
Catch Rate, Distribution, Trophic and Reproductive Biology of the African Carp Labeo coubie in the ... Agbokim Waterfalls, Nigeria
The catch rate, diet, size, and reproduction of 565 specimen of Labeo coubie were studied over 24 months (January 2005– January 2007) in three reaches [upstream, midstream (waterfalls region) and downstream] along the 6817.7 m length of Agbokim waterfalls during wet and dry seasons. Data were processed using fecundity (F), allometric coefficient (b), Fultons condition factor, and diet breadth. Fecundity values were 10411.0 ± 121, 15102.0 ± 303.5 and 24143.3 ± 662 eggs for fish from upstream, midstream, and downstream, respectively, with overall mean value of 19811.3 ± 223 eggs. The relationships of fecundity with total weight, ovary weight, ovary length, body breadth were positively linear. Mean allometric coefficient (b) of the length–weight relationship of fish in the three reaches were 2.662 ± 0.291 (upstream), 2.592 ± 0.368 (midstream), and 2.622 ± 0.315 (downstream) and all showed significant departure from cubic value (negative allometry). Detritus, phytoplanktons and plant materials were the dominant food items in the diet, contributing 36.8%, 32.1%, and 17.2% of stomach content, respectively. Food Richness of 7 and Gut Repletion Index, 100% were recorded. The low mean diet breadth exhibited by fish from the three sampling sites showed that the species has low trophic flexibility and cannot easily change feeding habit. Mean condition factor varied from 0.442 ± 0.127 upstream to 0.648 ± 0.146 downstream. Downstream therefore provided better spawning conditions for Labeo coubie in the tropical waterfalls ecosystems.
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Research Article
May 07, 2012
Aquaculture of Marine Fish in Inland Low Salinity Well Water: Potassium Is Not the Only Limiting E ... lement
Inland saline groundwater is abundant in various areas of the world but is not suitable for traditional agriculture irrigation and is also not suitable for marine aquaculture mainly because of potassium deficiencies. In the present work, we used marbled spinefoot rabbitfish Siganus rivulatus, as a model organism to investigate whether varying levels of aqueous K+ affect survival and growth, and whether ambient K+ has an effect on fish osmoregulation and haemolymph osmolality. A ten-week growth experiment was conducted where fish were reared in reconstituted inland saline water containing K+ concentrations equivalent to 15%, 40% and 100% (denoted as: Trt15, Trt40, and Trt100, respectively) of potassium in 15 ppt seawater. A 15 ppt seawater treatment (CSW) was used as a control. Fish weight, length, survival, Fulton-type condition index, blood and water osmolality, and serum Na+ and K+ concentrations were evaluated. Gill NKA activity was also estimated. Fish reared in Trt15 died during week 8. At the end of the experiment (week 10), no differences were observed in fish survival and total length among treatments Trt40 and Trt100 and control (P>0.05). Final weight was less in Trt40 and Trt100 than in CSW. Fulton-type condition index results showed that Trt100 was more suitable for fish than Trt40, but still not as suitable as 15 ppt sea water. Sodium (Na+ ) in serum was not affected by aqueous K+ levels, whereas serum K+ varied congruently with aqueous K+ . Rabbitfish reared in Trt40 and Trt100 had greater blood osmolality than those reared in control seawater. Gill NKA activity also increased by 50% in Trt40 and Trt100 as compared to control. The present study shows that potassium-deficient 15 ppt inland well water is not suitable for long-term culture of Siganus rivulatus. Results suggest that inland saline well waters greatly increase activity of NKA and consequently energy expenditure. Furthermore, K+ does not appear to be the only limiting mineral in inland low salinity groundwater that affects fish osmoregulation.
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Research Article
Nov 11, 2011
Probiotic-Based Nutritional Effects on Killifish Reproduction
Probiotic bacteria used as dietary additives seem to offer an attractive choice inducing overall health benefits to the host organism. It is well known that reproduction, in all vertebrates, is regulated by the reproductive axis and that nutrition affects reproductive events, from puberty to adult gametogenesis, in both sexes. Consequently, reproductive events are very closely aligned with the nutrition. The aims of this study were to investigate the effects of dietary probiotic administration on the marine teleost Fundulus heteroclitus and the effects of such broodstock dietary treatment on the growth and survival of the new progeny. Lactobacillus rhamnosus IMC 501® was administered daily as a feed additive, at a final concentration of 106 cfu ml-1 for 8 days. Gonadal growth (gonadosomatic index, GSI), fecundity, embryo survival and hatching rate of larvae from broodstock fed probiotic-supplemented diets were analysed as well as the biometric parameters (body weight, BW; total length, TL). The results demonstrated the beneficial effects of probiotics on the reproductive performance of this marine teleost, as the GSI, fecundity and embryo survival were significantly enhanced by probiotic administration. On the contrary, no effect on the hatching rate was shown. Moreover, broodstock probiotic-based nutrition affected the early stages of larval development of the new progeny: in detail, a significantly higher TL was shown throughout the experiment in the progeny derived from the probiotic (PRO) group bloodstocks compared to the control (CTRL) group; mean BW was significantly higher only at 30 days post-hatching (dph) while no change was observed in terms of larval survival. These results confirmed the positive effect of L. rhamnosus IMC 501® on the reproductive process of this marine teleost, but further work is required to better understand the mechanisms by which probiotics act on the reproductive axis as well as the nutritionally-/immunologically-mediated maternal effects on embryo and larval development and growth.
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Research Article
Aug 30, 2011
Effectiveness of Floating Micro-Bead Bio-Filter for Ornamental Fish in a Re-Circulating Aquacultur ... e System
Bio-filtration has been widely used in re-circulating aquaculture system to remove waste and to convert toxic ammonia and nitrite into safe end products ornamental fish and other aquatic organisms. However, the study of micro-bead usage as the filter medium has not yet been broadened and thoroughly developed. Therefore, the aim of this study is to construct a biological filter made from polyethylene micro-bead as the filter medium and to analyze its effectiveness in removing waste as well as in converting the toxic organic matter into stable substances. The bio-filter was constructed under a rotational molding process. The tubes, hoses, and piping were made from polyvinyl chloride (PVC) while the fasteners were made from stainless steel and other non-corrosive materials. The effectiveness of this bio-filter was measured by using biochemical oxygen demand (BOD) and total suspended solids (TSS) analysis. Results indicated that this bio-filter is efficient enough to remove suspended solids and BOD. Therefore, this floating micro-bead bio-filter can be used in aquaculture systems.
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Research Article
Apr 30, 2011
Changes in Ionic Ratios of Seminal Plasma and its Effect on Sperm Characteristics in Caspian Roach ... (Rutilus rutilus caspicus) During Spawning Migration
In this study, changes of ionic ratios (Na+ to K+ , Na+ to Ca+2, Na+ to Mg+2, K+ to Ca+2, K+ to Mg+2 and Ca+2 to Mg+2) during spawning migration of roach and its effect on sperm motility traits (sperm movement duration, percentage of motile spermatozoa) and sperm production characteristics (spermatocrit, sperm density and sperm volume) were investigated. Sperm of 30 males was collected during the spawning migration (February, March and April). Ionic ratios of Na+ to K+ , Na+ to Ca+2 and Ca+2 to Mg+2 significantly changed (P<0.05) between three terms, but Na+ to Mg+2 , K+ to Ca+2 and K+ to Mg+2 ratios did not show significant differences (P>0.05) between February, March and April. The results suggested that sperm movement duration is slightly influenced by (P<0.05) Na+ to K+ ratio. A similar tendency was observed in values of spermatocrit and percentage of motile spermatozoa due to Na+ to Ca2+ ratio. Also, Ca+2 to Mg+2 ratio influenced percentage of motile spermatozoa. The present study describes that biochemical composition (Ionic ratios) and semen characteristics will help in development of the basic knowledge and the strategies during artificial spawning programmes in this species.
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Research Article
Mar 29, 2011
Nanotechnology: A Novel Tool for Aquaculture and Fisheries Development. A Prospective Mini-Review
Nanotechnology has a tremendous potential to revolutionize agriculture and allied fields including aquaculture and fisheries. It can provide new tools for aquaculture, fish biotechnology, fish genetics, fish reproduction and aquatic health etc. Nanotechnology tools like nanomaterials, nanosensors, DNA nanovaccines, Gene delivery and smart drug delivery etc. have the potential to solve many puzzles related to animal health, production, reproduction, prevention and treatment of diseases. It is sensible to presume that in the upcoming years, nanotechnology research will reform the science and technology and will help boost livestock production. Nanotechnology applications in the fish processing industry can be utilized to detect bacteria in packaging, produce stronger flavors, colour quality, and safety by increasing the barrier properties. This paper presents the review of nanotechnology and its applications in aquaculture and fisheries.
