Search

Shell characteristics and consequent marketability of the oyster Crassostrea gigas are influenced by several factors, and most important of which are the rearing methods and gears. In this study, we investigated the effects of two different gears on the quality aspect (shell shape, weight meat percentage, backward shell shape, epibionts and blisters) and growth rate (weight and length) of C. gigas by adopting the innovative Ortac Oyster Farming System, during the field grow‐out phase of production. Aspect and growth of oysters farmed in Ortac and floating bags were compared. After 14 weeks, the aspect of the animals was influenced by the gear, resulting in a lower quality in the Ortac (i.e. worse shell shape, lower weight meat percentage, higher percentage of backwards and blisters) than in the floating bag, while the incidence of epibionts was less in the Ortac. Regarding the growth performance, total wet weight gained in the Ortac was lower (~28.3 g) than in the floating bag (~32.4 g; p

The seahorse has been used for thousands of years as an important traditional Chinese medicine (TCM) in China. Many species of wild seahorse have become endangered, but demand for them continues to grow rapidly. Therefore, it is urgent to cultivate seahorses to relieve the strain on natural populations and meet the market demand for this TCM. In this study, medicinal components of wild and cultured yellow seahorses (Hippocampus kuda Bleeker) were analysed and compared. Different parts of the body (cortex and bone), male and female specimens, and seahorses of different ages were analysed. Crude protein, crude fat, trace elements, calcium, amino acid, fatty acid, steroid and cholesterol content were measured. The results showed that moisture content accounted for 70% of wet weight and ash content increased with growth. Crude protein and fat contents were higher in cultured seahorses than in wild specimens, and the content of Zn in cultured seahorses (93.26 ± 10.44%) was significantly higher than that of same‐aged wild seahorses (74.20 ± 3.83%). Amino acid and fatty acid contents of cultured seahorses also were higher than those of wild seahorses. These findings show that cultured seahorses can also be used in TCMs and that 1‐year‐old cultured seahorses have the best properties.

The gonadosomatic (GSI) and hepatosomatic (HSI) indexes are widely used for the evaluation of reproductive biology in crustaceans. However, the use of either wet or dry weight for estimating these indexes is not standardized in the literature. Here, we compare the GSI and HSI indexes based on wet and dry samples of females of Macrobrachium amazonicum from populations with different phenotypes (large and small‐size prawns) as a model. In our analysis, for GSI, the application of wet weight tended to overestimate the values recorded in the initial (I‐II) and intermediate (III) stages of ovarian development, and underestimate the results in the final (IV‐V) stages when compared to the use of dry weight. This could be attributed to the reduction in cytoplasmic organelles and water content of the cytosol due to the increase in yolk and lipids in the oocytes throughout ovarian development. For HSI, no significant differences were detected between wet and dry samples. However, the dry HSI computed at all stages of development was overestimated when compared to the use of wet samples, and only the hepatopancreas of females at the final stage (V) showed a significant decrease in water content. Thus, our results indicate that M. amazonicum females maintain constant hepatopancreatic reserves throughout ovarian development. In this way, the use of dry weight is more adequate to estimate GSI and HSI in this species.

This study reports the presence of Cd, Pb, Zn, Hg, Cu, and Cr in the cockles (Anadara granosa, Linnaeus, 1758) harvested along the East Java Coast, Indonesia. The concentrations of metals were determined by atomic absorption spectrometer and expressed in mg kg-1 wet weight. The concentrations of metals ranged from 0.11 to 0.82 mg kg−1 for Cd, 0.10 to 0.54 mg kg−1 for Pb, 10.22 to 19.04 mg kg−1 for Zn, 0.02 to 1.47 mg kg−1 for Hg, 1.79 to 4.76 mg kg−1 for Cu, and 1.64 to 3.79 mg kg−1 for Cr. The metal concentrations in the whole tissues of cockles were in the order Zn>Cu>Cr>Hg>Cd>Pb. The Cd and Pb levels in cockles were found to be higher than the permissible limit for human consumption according to EC and FAO; the levels of Hg exceeded the EC, Hong Kong, Australia, and Indonesia standards; and the levels of Cr exceeded the Hong Kong standard. The estimated weekly intake (EWI) of cockles indicates that the concentrations of Cd and Hg in the cockle tissues from Gresik were higher than the provisional tolerable weekly intake (PTWI); meanwhile, the concentrations of Cr of cockles from all locations were higher than and close to the PTWI. The THQ values for Cd at Gresik, for Hg at Gresik, Surabaya, and Pasuruan, and for Cr at all locations were higher than one indicating that these metals pose potential noncarcinogenic effects to consumers. Reducing the consumption of cockles should be done in order to minimize the adverse effects of metals especially Cd, Hg, and Cr to human health.

A simple and fast method for the determination of PAHs in smoked meat samples was described. The QuEChERS (Z-Sep) procedure was used for sample preparation. Gas chromatograph-mass spectrometer with electron ionization (EI) was used to separate and detect the PAHs. All 16 common PAHs were analyzed successfully. Matrix-matched calibration was applied. Spiked samples were performed at 1 ng/g (n=10) and 10 ng/g (n=10) for two days. Overall recoveries of PAHs were within 74 to 117%, with RSDs within 1.15 to 37.57% and 1 and 10 ng/g wet weight for first and second day, respectively. In most of the analyzed smoked meat samples, there were no exceeded levels compared to the maximum levels declared by Commission Regulation (EU) number 835/2011. The method can be recommended for routine analysis for laboratories having a large number of samples.

In terms of nutrition, dates are an important commodity because they are a source of carbohydrates and minerals. Saudi Arabia is the second largest producer of dates worldwide. Khalas is the tenth most popular date type in the Kingdom of Saudi Arabia (KSA), but only limited information related to the levels of essential nutrients in Khalas dates is available. The concentrations of Mn, Cu, Zn, and Se were determined using inductively coupled plasma-mass spectrometry (ICP-MS). The average concentrations in wet weight were as follows (mg/kg): Mn (2.90 ± 0.54), Cu (1.78 ± 0.64), Zn (1.72 ± 0.42), and Se (0.10 ± 0.06). The calculated intakes (μg/kg bw day) per 100 g dates for each element were as follows: Mn (4.14), Cu (2.54), Zn (2.46), and Se (0.14), which represent 0.14%, 0.51%, 0.25%, and 0.2%, respectively, of the provisional maximum tolerable daily intake (PMTDI) recommended by the EFSA/WHO. It was found that levels of the analysed essential elements in up to 100 g of Khalas dates do not exceed the level set by the EFSA/WHO.

Summary This study investigated the age and growth of damselfish, Chromis notate, from Jeju Island in Korea. Samples were collected monthly by lift net from September 2013 to August 2014. Total lengths of the damselfish ranged from 6.4 to 15.3 cm. The relationship between total length and wet weight was WW = 0.0125TL3.1631 for females, and WW = 0.0091TL3.2769 for males. The slopes in the relationship between length and weight were not significantly different between sexes, but were significantly different in the intercepts. There were more female than male specimens (1.3:1). Age determination was conducted using the otoliths. Marginal increment (MI) declined in summer and winter, which suggests that two rings are formed each year. Ages of sampled individuals ranged from 1 to 5 years. Length-at-age data were fitted using the von Bertalanffy growth model. The estimated growth functions were Lt = 19.93 [1 − exp−0.21 (t + 0.811)] total length and wet weight was females, and Lt = 16.47 [1 − exp−0.32 (t + 0.499)] for males.

Recent work has established methods to engineer self-assembled, scaffold-free neocartilage from an expanded articular chondrocyte (AC) cell source. In continuing such work, the objective of the present study was to investigate the effects of cell-seeding density and dexamethasone concentration on these neocartilage constructs. Neocartilage discs (5 mm diameter) were formed by self-assembling passaged leporine articular chondrocytes into non-adherent agarose moulds. The cell-seeding densities (2, 3, 4, 5 and 6 million cells/construct) and dexamethasone concentrations (10 and 100 nm) in the culture medium were varied in a full-factorial study. After 4 weeks, the neocartilage constructs were assessed for morphological, biochemical and biomechanical properties. The cell-seeding density profoundly affected neocartilage properties. The two dexamethasone concentrations explored did not induce overall significant differences. Constructs formed using lower cell-seeding densities possessed much higher biochemical and biomechanical properties than constructs seeded with higher cell densities. Notably, the 2 million cells/construct group formed hyaline-like neocartilage with a collagen wet weight (WW) content of ~7% and a Young's modulus of ~4 MPa, representing the high end of values achieved in self-assembled neocartilage. Excitingly, the mechanical properties of these constructs were on a par with that of native cartilage tissues tested under similar conditions. Through optimization of cell-seeding density, this study shows for the first time the use of expanded ACs to form homogeneous self-assembled neocartilage with exceptionally high tensile strength. With such functional properties, these engineered neocartilage constructs provide a promising alternative for treating articular lesions. Copyright © 2016 John Wiley & Sons, Ltd.

Summary The Lake Eyre Basin in central Australia is one of the world's last unregulated dryland river systems. To facilitate future research in this area, the relationships between total length, standard length, and wet weight for 10 widespread, large-bodied freshwater fish species are presented. All linear relationships were strong (r2 > 0.90) and values of the exponent b of the length–weight relationships ranged from 2.786 to 3.336. These results provide novel baseline data for species in this area.

The basket cockle (Clinocardium nuttallii) is a candidate species for aquaculture in the northeast Pacific. The aim of the current research was to assess the feasibility of C. nuttallii grow-out, with an emphasis on growth performance and qualities affecting product marketability. In this article, we investigated the combined effects of culture mode (intertidal and off-bottom suspended culture) and initial stocking density (1500, 3000, 10 500 and 21 000 ind m−2) on C. nuttallii survival and growth during the first year of grow-out (May through October). In intertidal culture, cockles exhibited low survival and poor growth rates. In suspended culture, survival was consistently high (>96%) at all stocking densities tested; growth and condition parameters had the highest values at 1500 and 3000 ind m−2. The edible portion (meat yield) exceeded 40% of the whole wet weight at all stocking densities, occurrences of fouled and deformed cockles were

Commercial bath sponge population in the Mediterranean has been recently reduced due to diseases and the depletion of natural banks. The commercial supply is far below the demand on the last 10–15 years. In this study, we aimed to investigate the farming performance of Spongia officinalis in the Dardanelles. Sponges collected from the Dardanelles cut into pieces of different weight. They were divided into two groups depending on the wet weight ranging from 50 to 150 g (mean weight 102.6 ± 4.81 g) and from 160 to 360 g (mean weight 235.8 ± 8.56 g). Three rope systems located parallel to each other with 6–7 m inter-distance were constructed for the cultivation of sponges. At the end of the study, while small-sized sponges could reach mean wet weight of 120.7 ± 14.8 g, large-sized sponges reached mean wet weight of 247.6 ± 22.4 g. Growth rates were estimated 5–17% at 21st month. The survival rates were found 82% and 88%.

Seawater sampling from three abalone farms in New Zealand showed average ambient concentrations of dissolved inorganic phosphate (Pi) varying between 2.36 and 238 μM. The Pi concentration within each system appeared to be directly linked to the percentage of water that was replaced each day. An experiment was conducted over 5 months to examine the effect of elevated Pi concentrations on the growth of two juvenile abalone (Haliotis iris) size classes (small: average shell length=23.9 ± 0.1 and large: average shell length=61.9 ± 0.1 mm). Abalone from each size class were exposed to Pi concentrations of; (a) natural incoming seawater (average 0.12 ± 0.12 μM), (b) 10.7 ± 1.3 μM, (c) 60.9 ± 5.8 μM and (d) 113.1 ± 5.6 μM. The results suggest that over the course of the 5-month period of this experiment there was a significant negative impact on growth (shell length and wet weight) when the smaller size class of abalone were exposed to Pi concentrations greater than 10.7 μM and for the large size class of abalone when exposed to greater than 60.9 μM Pi. However, elevated Pi concentrations did not significantly impact on abalone survival during the course of the experiment.

The effect of chitosan, a polymer of glucosamine obtained by the deacetylation of chitin, on growth, survival and stress tolerance was studied in postlarval Litopenaeus vannamei. An experiment was performed with postlarval shrimp (mean initial wet weight 1.2 mg) fed five isoenergic and isonitrogenous diets containing five supplemented levels of chitosan (0, 0.5, 1, 2 and 4 g kg−1 diet, respectively). The five compound diets (C0, C0.5, C1, C2 and C4) sustained shrimp growth throughout the experiment. Growth performance (final body weights; weight gain; SGR: specific growth rate) in shrimp fed diet C2 was significantly higher than that in shrimp fed diets C0, C0.5 and C1 (P

One experiment was conducted to determine the nutritive value of phospholipids on growth performance of early postlarval shrimp, Litopenaeus vannamei. Five isoenergic and isonitrogenous diets with five supplemented levels of phospholipids (P1, P2, P3, P4 and P5 with 0, 10, 20, 40 and 80 g kg⁻¹ diet, respectively) were fed to triplicate groups of L. vannamei (mean initial wet weight 0.8 mg) for 27 days. After the 27-day feeding trial, the lowest weight gain (WG, %) and specific growth rate (SGR, % day⁻¹) was found in P1 treatment, the highest WG and SGR was found in P3, P4 and P5 treatments, P2 treatment provided intermediate result and showed significant difference compared to P1, P3, P4 and P5 treatments. Shrimp fed the P1 diet had significantly lower survival than shrimp fed other diets, while no significant difference was found in survival among P2, P3, P4 and P5 treatments. Broken-line analysis on WG indicated that the optimum dietary phospholipids for early postlarval shrimp, L. vannamei, is 45.96 g kg⁻¹ diet.

Three experiments were designed to investigate the heat increment of feeding (HiE) in Chinese shrimp, Fenneropenaeus chinensis. (1) Four groups of shrimp with different weight were fed at four rations to measure oxygen consumption in the following 24 h. (2) Four groups of shrimp with different weight were fed with four rations for 28 days. (3) Fish flesh, shrimp flesh, clam foot, polychaette worm, formulated diet and mixed diet were provided to six groups of shrimp for 30 days. The coefficient of heat increment of feeding (CHiE) values within 24 h after ingesting 1 g digestible protein (DP) and 1 kJ digestible energy (DE) were 18.57 kJ and 0.45. CHiE values of 1 g DP and 1 kJ DE achieved in the second experiment were 25.06 kJ and 0.57. The energy cost of 1 g wet weight gain, 1 g protein gain and 1 kJ recovered energy were 13.94, 32.16 and 1.07 kJ. They accounted for 69.28%, 26.71% or 40.23% of HiE of the meals needed for these growths. The present results indicated that HiE was a fundamental property of the feed and the energy cost of growth accounted for different fraction when different feeds were ingested.

Three Pavlova species were evaluated for their nutritional value as diets for growth and survival of the Cortez oyster Crassostrea corteziensis spat during late-nursery cultivation at a hatchery. Microalgae were provided as monospeci¢c diets (Pavlova salina, P .s p. C50 andP. sp. C53) and in binary combinations of diets112,1 1 3a nd 213 at 80^90 10 3 cells mL 1 for 21 days. Juveniles experienced high survival rates and grew well with all dietary treatments, but binary diets yielded greater survival and growth of spat. From the three binary treatments, Diet 6 (P .s p. C50 andP. sp. C53) promoted signi¢cantly (Po0.001) fastest growth of juveniles in shell height (0.19 mm day 1 ), shell length (0.14 mm day 1 ), total wet weight (0.04 g day 1 ) and dry weight of meat biomass (0.024 g day 1 ). For all shell dimensions, the lowest growth rates occurred with Diets 2 (P .s p. C56 alone) and 3 (P. sp. C50 alone). These results highlight the importance of testing microalgal diets for bivalve spat rather than just relying on published nutritional values.

Quantitative benthic samples were taken during spring and summer at three locations on the Louisiana continental shelf from 2004 to 2012 to assess the influence of hypoxia on the mean sizes (wet weight) of polychaete annelid worms. While the mean body size over the entire study of 64 samples was 3.99 ± 4.66 mg wet weight per individual, the mean ranged from 2.97 ± 2.87 mg during consistently hypoxic conditions (p<0.01) under oxic conditions (>2 mg/L). The variations in size within assemblages were estimated from conventional biomass size spectra (BSS) and normalized biomass size spectra (NBSS) across a broad range of oxygen concentrations. The decline in size was due to the elimination of large species under hypoxic conditions (Paraprionospio pinnataflourished. These results suggest that there will be enhanced selection for small sizes and species with enlarged branchial palps such as those inP. pinnataif, as predicted, hypoxia becomes more commonplace in time and space worldwide.

Summary The relationships between total (TL) and standard (SL) lengths for 50 fish species and between TL and wet weight for 52 fish species caught in the Oueme River are presented. Relationships between TL and SL are linear. Between TL and weight, the relationships are of the form TW = aTLb. The b values range from 2.3307 to 3.5185. Student's t-test revealed that 38.5% of the species have b values significantly different from 3.

The thermoregulatory behaviour of green abalone Haliotis fulgens and pink abalone H. corrugata was investigated. Haliotis fulgens juveniles ranging in wet weight from 3.0 to 3.3 g and from 28.7 to 30.5 mm shell length and of H. corrugata 2.0 g and 25.7 mm in shell length were exposed to 19°C for 30 days in a flow-through water system. Temperature preference was determined in a horizontal thermal gradient and was found to be 25.4°C for green abalone and 25.0°C for pink abalone. Displacement velocity was 4.3 cm h⁻¹ for H. fulgens and 12.8 cm h⁻¹ for H. corrugata. The optimum temperature for growth calculated for both abalone species was 24.6 and 24.5°C respectively. The critical thermal maxima (CTMax) of H. fulgens and H. corrugata were determined as a measure of thermal tolerance. Abalones were subjected to increasing water temperatures at a rate of 1°C on 30 min until they detached from the substrate. The CTMax at 50% were 33.6 and 32.0°C for green and pink abalone respectively. The results are discussed in relation to site selection and commercial rearing.

Daily food intakes, optimal feeding regimes and food concentrations for laboratory reared Paralithodes camtschaticus (Tilesius, 1815) larvae were investigated. Artemia nauplii hatched at standard conditions were used as food. Daily food intakes of zoeae I–IV at 7–8 °C comprised 11.3, 22.4, 33.2, and 41.8 nauplii individuals (ind)−1 day−1, respectively, taking into account that wet weight of Artemia nauplii used for the experiments constituted 0.026 mg, dry weight 0.0042 mg. Optimal initial Artemia nauplii concentrations for feeding zoeae I–IV was determined as 400–600, 600–800, 800–1000 and 1000–1200 nauplii L−1 respectively. Recommendations on using Artemia nauplii as food for red king crab larvae were outlined on the basis of experimental results. Growth, development and survival rates of zoeae I–IV reared in recycling water system at 7–8 °C and fed Artemia nauplii according to these recommendations were described.

This study was carried out to quantify the transfer of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) from commercial fish feed into the edible part of rainbow trout (Oncorhynchus mykiss, Walbaum) under normal rearing conditions. Trout were fed with high-energy feed for salmon (fat content 26–30%) over a period of 19 months. The average weight of the fish increased from 10 g to more than 2092 g, reaching a size of up to 51-cm length (Tl). Considerable amounts of PCDDs and PCDFs were transferred from the fish feed into the tissue of the trout. Dioxin concentrations increased during the time of feeding from 0.054 up to 0.914 ng WHO-PCDD/F-TEQs kg−1 wet weight and from 4.991 to 15.815 ng WHO-PCDD/F-TEQs kg−1 fat. A correlation was found between the dioxin concentration of the feed and the resulting concentration in the fat of the muscle tissue. The data allow the establishment of transfer rates from a high-energy diet to farmed rainbow trout.

Summary Early gonad development of the Asian sea bass (Lates calcarifer) grown in a freshwater recirculation system was investigated to determine the onset of sexual maturation. Studied individuals aged between 9 and 15 months. Culture conditions were provided initially in circular tanks (4000 L) and linked to a warm-water recirculation system (27°C, O2 = 7‐ 8 mg L ! 1 ) until they reached 20 g wet weight. They were ongrown in raceways (54 m 3 ; final density 80 kg m ! 3 ) connected to a recirculating system with a fluidized bed as biofilter. Their gonads were examined each month (5‐12 fish) and prepared for histology. Following microscopic observations testis maturity was categorized and correlated to total length (cm) and weight (g). Gonad development started much earlier in the recirculation system than described previously in both, wild and cultured fish. We assume that spermatogenesis in these fish starts earlier than 9 month of age and the fact that mature spermatozoa were present in testes that contained mostly spermatogonia indicates highly asynchronous spermatogenesis.

Summary The relationships are given between total length and wet weight, and between total length and standard length for 10 scorpionfishes from the south coast of Korea.

The preferred temperature (PT) of Poecilia sphenops (Pisces, Poeciliidae) (n = 240; 1.13 +/- 0.06 g wet weight; 3.26 +/- 0.88 cm standard length) from Presa Piedra Azul, Oaxaca, Mexico, was measured at acclimation temperature of 20 degrees C, 23 degrees C, 26 degrees C, 29 degrees C, 32 degrees C and 35 degrees C. The thermal preference of males was 25.5 degrees C in summer and 29.6 degrees C in winter; whereas females preferred 29 degrees C in both seasons. Fish held at 20 degrees C and 23 degrees C preferred temperatures 36% higher than their acclimation temperature (AT), and those held at 35 degrees C and 32 degrees C preferred 30% and 20% lower temperatures than their AT. In intermediate temperatures, no significant differences between PT and AT were found. The interval of thermal selection based on the higher (HAT) and lower (LAT) avoidance temperatures was of 10-14 degrees C and not different between sexes in both seasons. Knowledge of the thermal biology of P. sphenops based on the preferred and avoidance temperatures was very important in order to understand the capacity of the species to adapt to the thermal changes occurring in its habitat. Based on the results, we can recommend the use of P. sphenops in aquaculture owing to its thermal plasticity.

Summary We present the relationships between total (TL), fork(FL) and standard (SL) length for 37 fish species and the relationships between TL and wet weight for 40 fish species from the Aegean Sea (Cyclades; Greece). The relationships between TL, FL and SL were all linear (for all cases: r 2 > 0.928). The values of the exponent b of the length–weight relationships ranged from 2.235 to 3.704.

This research was done with the purpose to ascertain the biological feasibility of the culture of Crassostrea virginica (Gmelin 1971) at Rio Lagartos lagoon in Yucatan, Mexico. Spat from two localities of the Golfo de Mexico were grown in Nestier boxes: spat from Tamiahua, Veracruz, which had an initial average height of 22.50 ± 5.10 (SD) mm and initial total wet weight of 2.90 ± 1.64 g and spat from Mecoacan, Tabasco, that were 32.05 ± 4.50 mm and 5.53 ± 0.03 g, respectively. Both groups of oysters reached commercial size after 10 months of culture. Veracruz spat reached 65.00 ± 6.80 mm in height and 33.26 ± 7.02 g in total wet weight. Those from Tabasco reached 62.90 ± 6.70 mm in height and 33.97 ± 9.95 g in total wet weight. The mean physiological condition index for oysters from Tabasco was 5.96% and from Veracruz was 4.52%. Total survival rate was 63% for spat from Veracruz and 55% from Tabasco. Environmental conditions in the culture area proved to be favourable for the rearing of C. virginica.

The objective of this study was to determine the dietary phosphorus (P) requirement of juvenile Atlantic salmon, Salmon salar L. Triplicate groups of fish (mean initial weight 1.4 g) were fed semipurified, casein-gelatine-based diets containing one of five levels of P (4, 8, 10, 15 and 25 g kg−1) from Ca(H2PO4)2·H2O, or a commercial feed (17 g kg−1 P) for 9 weeks. Weight gains did not differ significantly among treatment groups fed the experimental diets but were slightly less than gains in fish fed the commercial feed. Feed efficiency (wet weight gain/dry feed consumed) was similar in all groups, averaging 1.45. Availability of dietary P, estimated from apparent retention and apparent digestibility, was 86%. Whole-body P concentrations declined in fish fed diets containing less than 10 g kg−1 P. Fitting a logistic curve to dietary P vs. whole-body P concentrations indicated that a minimum of 11 g kg−1 dietary P (9 g kg−1 digestible P) was required by juvenile Atlantic salmon to maintain whole-body P concentrations at initial levels. Calculation of a dietary requirement using a simple factorial model which incorporated measurements of P availability, feed efficiency and normal whole-body P concentration indicated that the dietary requirement was approximately 10 g kg−1. The dietary requirement established in this study (10–11 g kg−1) is higher than previously reported for Atlantic salmon or other fishes. Possible reasons for the wide range of reported dietary P requirements in fishes are discussed.

Morphological and histological studies demonstrated that 17 α-methyltestosterone (MT) affects sex differentiation and can be used to control the phenotypic sex of pikeperch. Stizostedion lucioperca L. Treatment (for 21 days) of pikeperch (initially 2.2 g wet weight) with MT at 30 mg kg-1 diet induced germ cells inversion in approximately 46.67% of individuals (although 96.67% of the fish were classified as males). An increase in treatment duration (60 and 90 mg kg-1) increased the percentage of female, intersex and sterile fish. Slower growth rates of all the fish treated with MT in comparison to the control groups were demonstrated. However, no significant differences in conditions and mortalities between the MT treated fish and controls were observed.

Characteristics and gel properties of gelatin from goat skin, as influenced by extraction conditions, were studied. Yield of gelatin was 22.1–23.1% (wet weight basis). All gelatins contained α-chains as the predominant components, followed by β-chain. However, no β-chain was retained when extracted at 70C. Gelatin extracted at 50C for 2.5 h exhibited the highest gel strength (267 g) (P

Field-caught fry of the common wolfish, Anarhichas lupus L., and the spotted wolffish, A. minor Olafsen, were reared on a commercial dry pellet. Both species experienced the same environmental conditions, including an annual fluctuation in temperature from 5·8 to 13·7°C. The spotted wolffish reached 1·58 kg in 2 years from hatching, more than four times the weight of common wolffish (0·37kg). Analysis showed that for both species the specific growth rate decreased with increasing fish size and increasing temperature. Estimates, based upon optimum conditions, indicate that the spotted wolffish would reach a total wet weight of 5 kg (

ummary Routine oxygen consumption of turbot, Scophthalmus maximus, was determined in relation to temperature, salinity, body wet weight, and time of day. The highest routine oxygen consumption rates measured roughly followed a arabolic curve over the temperature range tested (8 to 24°C). The lowest rates showed a more linear refationship over the same temperature range. It is argued that lowest rates correspond to the standard oxygen consumption. Between 16 and 19°C, routine oxygen consumption reached a maximum. It is suggested that these temperatures correspond to the preferred ternerature of the species and are within the range of optimum temperature for growth of specimens weigkng about 100 g. Salinity effect on oxygen consumption rates was studied in five groups acclimated over 4 weeks to 8, 15, 22, 29, and 35%. salinity. Routine oxygen consumption rates were lowest at 8% salinity with no significant differences in higher acclimation salinities. Routine respiration of turbots showed conspicuous daily fluctuations. During spring, summer, and autumn, oxygen Consumption was higher during morning hours and at night. In winter, higher rates were measured only once (during morning and early afternoon). The relationship between routine oxygen consumption and body weight of turbots followed an exponential function with a slope of 0.7, which was lower compared to the slope of 0.8 usually given for roundfish-species. Zusammenfassung Der Einflus van abiotischen und biotischen Faktoren auf den Routinestoffwechsel des Steinbutt Scophthalmus maximus Der Sauerstoffverbrauch von Steinbutt, Scophthalmus maximus, wurde in Abhangigkeit von derTemperatur, dem Salzgehalt, derTageszeit und dem Korpergewicht auf dem Niveau des Routinestoffwechsels gemessen. Die Temperaturabhanigkeit (8–24°C) fur die hochsten gemessenen Sauerstoffverbrauchsraten folgte einer Parabel, watrend die niedrigsten Raten eher einer linearen Abhangigkeit unterlagen. Es wird diskutiert, das der untere Wertebereich eher dem Standard-Stoffwechsel des Steinbutt zuzuordnen ist und die Vorzugstemperatur fur diese Art (Nasgewicht der Tiere um 100 g) im Bereich der maximalen Stoffwechselaktivitat (16–19°C) liegt. Der Einflus des Salzgehaltes auf die Stoffwechselaktivitat von Steinbutt wurde bei 8, 15, 22, 29 und 35% Salzgehalt untersucht, an den die Tiere mindestens vier Wochen adaptiert worden waren. Die Sauerstoffverbrauchsraten waren nach der Adaptation an 15 bis 35 % Salzgehalt signifikant hoher verglichen mit den Raten, die nach Adatation an 8% Salzgehalt gemessen worden waren. Der Routinesauerstoffverbrauch unterlag einem Seutlichen Tagesgang: Messungen wahrend des Fruhjahrs, im Sommer und Herbst erbrachten einen Anstieg der Stoffwechselaktivitat in den Morgen- bzw. Abendstunden; im Winter nahm die Aktivitat nur noch einmal wahrend des Tages zu. Die Gewichtsabhangigkeit des Sauerstoffverbrauchs von Steinbutt folgt einer Exponentialfunktion, deren Exponent (0.7) niedriger ist, als im allgemeinen fur Fische (0.8) angenonimen wird.

ummary Oreochromis niloticus were cultured during a six month period using underground water (salinity about 2.7%) in an intensive culture system comprising six circular tanks, each with a volume of 150 m3. Continuous aeration and mixing of water using floating pumps was combined with periodic removal of settled solids from the pond bottom by daily hushing out 50% of the tank water volume. Initial mean wet weight of fish in all tanks varied from 15 g to 52 g. Locally produced pellet feed containing 30 % raw protein was used at 3% per day of the biomass (dry to wet weight basis). The mean final weight in the system was 163 g, 110 g and 87 g, at a specific growth rate (SGR) of 0.72, 0.92 and 0.98, respectively, in tanks usin stocking rates of 60, 100 and 140 fish. m-3. Pertinent parameters of water chemistry and biological factors were determined at regular intervals. Water quality appeared to be less satisfactory in all tanks. Oxygen, pH and turbidity seemed to be in the anomalous range during the entire period of fattening, especially at high stocking rates. Rotifers and Protozoa were common organisms in the culture medium, whereas Cyanophyta, Chlorophyta, Euglenophyta and Chrysophyta were the more common algae. Chlorophyll-a concentrations ranged from 146 pg. L-1 during April, to 378 μg. L-1 during September. With regard to the weekly observations, chlorohylla were between 90 to 115 μg. L-1 just after completion of the weekly tank cleaning. In mid-week, bloom increased, causing a triple increase in chlorophyll-a which ranged from 240 to 305 μg. L-1. Some cost-benefit aspects of the operation are also discussed. Zusammenfassung Tilapia (Oreochromis niloticus) Biomasse-Ertrage in einer kommerziellen Fischfarm unter Venuendung von Rundbecken Oreochromis niloticus wurden uber 6 Monate in einer Intensivanlage gezuchtet, die aus 6 Rundbecken mit jeweils 150 m3 Wasservolumen bestand und mit Grundwasser versorgt wurde (Salzgehalt etwa 2.7%). Kontinuierliche Beluftung und Zirkularion wurde durch an der Oberflache schwimmende Pumpen erreicht und mit periodischer Entfernung der am Beckenboden abgesetzten Feststoffe kombiniert, wobei taglich etwa 50% des Beckenwassers ausgetauscht wurden. Mittlere Anfangsgewichte der Fische variierten in allen Becken zwischen 15 g und 52 g. Lokal hergestelltes Pelletfutter mit 30% Rohprotein wurde mit 3 % Korperbiomasse pro Tag verfuttert (auf der Basis Trockengewicht Futter zu Nasgewicht Fisch). Das mittlere Endgewicht der Fische im System betrug 163 g, 110 g, und 87 g, mit einer entsprechenden spezifischen Wachstumsrate (SGR) von 0,72, 0,92 und 0,98 in Becken mit einer Besatzdichte von 60, 100 und 140 Stuck. m-1. Wichtige Wasserqualitatsparameter und biologische Faktoren wurden in regelmisigen Abstanden bestimmt. Die Wasserqualitat war in allen Becken nicht zufriedenstellend. Sauerstoffgehalt, pH-Wert und Trubung waren wahrend der gesamten Abwach-sphase suboptimal, dies gilt besonders fur die hohen Besatzdichten. Radertierchen und Protozoen waren verbreitete Organismen im Kulturmedium, wahrend Cyanophyceen, Chlorophyten, Euglenophyten und Chrysophyten die ublicherweise vorhandenen Algen bildeten. Die Chlorophyll-a Konzentration variierte zwischen 146 μ. L-1 im April und 378 μ. L-1 im September. Unmittelbar nach der wochentlichen Beckenreinigung erreichten die Werte nur 90 und 115 μ. L-1. In der Mitte der Woche ergab die steigende Algenblute eine Verdreifachung des Chlorophyll-a-Gehaltes auf Werte zwischen 240 und 305 μ. L-1. AbschlieBend werden einige Aspekte zur Kostengestaltung des Betriebes diskutiert.

Summary The relationships are presented between total length and wet weight and between total length and standard length for four species of righteye flounder from the south coast of Korea.

Summary The relationships of total length (TL), fork length (FL) and standard length (SL) are presented for four fish species and the relationships between TL and wet weight for 23 fish species from the Chi River in northeastern Thailand. All length–length relationships were linear (r2 > 0.95). Slope (b) of the length–weight relationships showed values between 2.5073 and 3.4896.

Disk-shaped adhesive tablets, for treatment of mouth lesions, were prepared by direct compression of a mix of high viscosity sodium carboxymethyl-cellulose and 0.061% betamethasone valerate. They were evaluated in six healthy volunteers. The tablets hydrated rapidly, increased their wet weight fourfold in 15 min and maintained contact with the oral mucosa for at least 4 h. Erosion of the tablets was variable with only minor losses in one subject at all times tested, whereas over 80% tablet weight loss occurred in two subjects after 2.5 h. These differences were not solely related to differences in salivary flow. Loss of betamethasone occurred in parallel with the loss of weight from the tablet suggesting that drug release was mainly by erosion of the gelled polymer and not by diffusion from the matrix. The tablets provided prolonged contact with the mucosa but the intersubject variability and drug loss should be addressed to improve the formulation.