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1.
A.S. GARCIA C.C. PARRISH J.A. BROWN S.C. JOHNSON S. LEADBEATER 《Aquaculture Nutrition》2008,14(5):431-444
We evaluated the effects of enriched rotifers on growth, survival and on the lipid composition of haddock larvae. The treatments tested were (1) AlgaMac 2000®, (2) AquaGrow® Advantage and (3) Pavlova sp. paste and AlgaMac 2000®. The treatments did not influence larval growth rate throughout the experimental period (P = 0.70). Larvae from all treatments grew approximately 8% of their dry weight per day between 1 and 29 days post hatch (dph). Treatment 3 resulted in the best survival, estimated to be 3 on a scale from 0 to 5, whereas for the two other groups the survival estimates were 0 and 2. Rotifers from treatment 1 had low sterol concentrations, high eicosapentaenoic acid/arachidonic acid ratio and their feeding resulted in high larval mortality. Rotifers enriched with Pavlova sp. had the lowest proportions of the sum of saturated fatty acids, docosahexaenoic acid and sum of ω3 and the highest proportions of the sum of monounsaturated fatty acids (ΣMUFA). This was partially reflected in larvae from treatment 3 in that they had the highest proportions of ΣMUFA and the lowest proportions of Σω3 (P < 0.0001 for both analyses). In addition, these larvae had the highest and lowest ΣC20 and ΣC22 polyunsaturated fatty acids (PUFA) respectively (P < 0.0001 for both analyses). We suggest that more research with ω3 and ω6 PUFA can lead to improvements in the rearing of haddock larvae produced in hatcheries. 相似文献
2.
Influences of mean advection and simple behavior on the distribution of cod and haddock early life stages on Georges Bank 总被引:2,自引:0,他引:2
FRANCISCO E. WERNER FRED H. PAGE DANIEL R. LYNCH JOHN W. LODER R. GREGORY LOUGH R. IAN PERRY DAVID A. GREENBERG MICHAEL M. SINCLAIR 《Fisheries Oceanography》1993,2(2):43-64
Results of a modeling study designed to explore the influences of physical advection and certain biological mechanisms on the distribution of cod (Gadus morhua) and haddock (Melarwgrammus aeglefinus) early life stages on Georges Bank are described. Using a late-winter/early-spring 3-D circulation field driven by the M2 tidal current, mean wind stress and Scotian Shelf inflow, we examine the distribution of cod and haddock larvae spawned on the Northeast Peak of the Bank. The sensitivity to a March-April baroclinic field is also explored. Results indicate that larvae remaining in the surface Ekman layer are generally advected off-bank. However, downwelling associated with Ekman layer convergence near the shelf break provides a mechanism for larvae to exit from the off-bank surface drift. Larvae below the surface layer are transported south-westward along the southern flank of Georges Bank and are retained on the Bank if their position immediately upstream of the Great South Channel is shoalward of (roughly) the 70 m isobath. Within the Great South Channel region and between the 50 and 70 m isobaths, retention can depend on the phase of the tide. Spawning shoalward of the 50 m isobath on the Northeast Peak greatly increases the chances of retention. These results apply to passive larvae and to those with specified vertical distributions and migration based on observations. Directional on-bank swimming at rates of 0.5 to 1 body length per second would substantially enhance shoalward displacement, resulting in larval distributions during the first 2 months that are consistent with field observations. 相似文献
3.
Growth,Survival, and Whole‐body Proximate and Fatty Acid Composition of Haddock,Melanogrammus aeglefinus L., Postlarvae Fed a Practical Microparticulate Weaning Diet 下载免费PDF全文
Further development of high‐quality feeds for hatchery‐reared haddock in the North Atlantic would benefit from a standard formulation that can be used as a reference for hatcheries and laboratory studies. A practical microparticulate diet (PMD) developed and evaluated with newly metamorphosed juvenile haddock, Melanogrammus aeglefinus L., postlarvae is proposed. Survival of fish fed PMD was just as high (88–89%; P > 0.05) as those fed a high‐quality imported feed (Biokyowa). Alternatively, fish fed PMD had higher (P < 0.05) final fork lengths (39.5 vs. 35.1 mm), wet weights (851.3 vs. 580.2 mg) and weight gains (1637.2 vs. 1115.7%). No differences (P > 0.05) in whole‐body moisture (846–857 g/kg), ash (17–18 g/kg), or protein (101 g/kg) contents were found. Lipid content of fish fed PMD (26 g/kg) was higher (P < 0.05) than those fed Biokyowa (21 g/kg) despite PMD containing 15 g/kg lower dietary lipid, suggesting higher intake and/or lipid retention. The PMD formulation proved to be a highly suitable weaning diet for haddock postlarvae based on high feed acceptance, survival, and fish growth. Given the economic and logistical difficulties associated with importing commercial weaning feeds, this easily produced practical weaning diet has good potential for use by laboratory researchers and farm managers for hatchery‐based nutrition research with haddock postlarvae. 相似文献
4.
Gavin Downing 《Aquaculture Research》2002,33(4):251-259
In a small‐scale culture experiment, larval haddock, Melanogrammus aeglefinus L., were raised under various combinations of light quality [blue (470 nm), green (530 nm) or full‐spectrum white light] and light intensity [low (0.3–0.4 µmol s?1 m?2) or high (1.7–1.9 µmol s?1 m?2)], and in total darkness (both fed, and starved). Larval growth (0.9% day?1 in standard length; 2.4% day?1 in body area) was not significantly different between any combination of coloured light. At the time of total mortality in the starved treatment, survival was significantly reduced under low intensity, full‐spectrum white light (13%) vs. all other coloured light treatments (68%). Larvae raised under both continuous dark treatments (fed and starved) exhibited morphological changes associated with irreversible starvation (point‐of‐no‐return). Lack of a pronounced effect of light quality on larval haddock growth probably results from a combination of plasticity in early larval vision, and enhanced encounter rates between larvae and prey at the relatively high prey densities used in aquaculture. 相似文献
5.
Apparent digestibility of common feed ingredients by juvenile haddock, Melanogrammus aeglefinus L. 总被引:2,自引:0,他引:2
The digestible energy (DE) content and the apparent digestibility coefficients (ADCs) of nutrients in common feed ingredients available in Atlantic Canada for haddock, Melanogrammus aeglefinus, feed formulations were determined. Juvenile haddock (mean weight, 93.9±2.1 g) were held in tanks equipped with fecal collection columns and fed practical fish meal‐based diets for 5 weeks. The experimental diets consisted of a reference diet and six test diets, each containing 30% test ingredient, with all diets being supplemented with chromic oxide (Cr2O3, 5 g kg?1) as the inert digestion indicator. Three marine fish by‐products, herring meal (HM), shrimp meal (SM) and crab meal (CRM) and three plant protein supplements, dehulled soybean meal (SBM), canola meal (CAM) and corn gluten meal (CGM) were the test ingredients. The DE content of HM, SBM, CGM, CRM, CAM and SM were 18.3, 18.0, 17.8, 12.4, 10.9 and 8.8 MJ kg?1 respectively. Protein ADCs were 95.9%, 92.2%, 92.3%, 82.0%, 83.0% and 73.5% respectively. Organic matter ADCs were 95.9%, 89.0%, 72.6%, 68.9%, 58.9% and 54.9% respectively. Lipid ADCs were 97.9%, 83.0%, 57.4%, 62.0%, 87.2% and 55.8% respectively. Based upon its high crude protein content and nutrient ADC and DE content, properly processed dehulled SBM was found to be a good plant protein supplement to partially replace HM in haddock feeds. 相似文献
6.
Assessment of sex and evaluation of ovarian maturation of fish using ultrasonography 总被引:6,自引:0,他引:6
Ultrasonography is a non‐invasive method that can be used to assess sex and maturity of fish. This study was conducted to examine the feasibility of using ultrasound images to sex juvenile and mature halibut Hippoglossus hippoglossus (Linnaeus), mature winter Pleuronectes americanus (Walbaum) and yellowtail flounder Pleuronectes ferruginea (Storer) and mature haddock Melanogrammus aeglefinus (Linnaeus). In females, both immature and mature ovaries were relatively easy to distinguish, but in males only mature testes were consistently distinguishable. Ovarian maturation of haddock and ovulatory cycles of halibut may also be assessed using ultrasound. 相似文献
7.
F. H. Page M. Sinclair C. E. Naimie J. W. Loder R. J. Losier P. L. Berrien & R. G. Lough 《Fisheries Oceanography》1999,8(3):212-226
The seasonal and geographical patterns of spawning for Georges Bank cod ( Gadus morhua ) and haddock ( Melanogrammus aeglefinus ) are estimated using composite distributions of stage I eggs derived from the Marine Resources Monitoring, Assessment and Prediction (MARMAP) data set (1977–1987). The inferred mean spawning locations are compared with patterns in particle residence times derived from a three-dimensional prognostic circulation model that estimates the tidal and seasonal mean circulation. The comparisons indicate that cod and haddock spawning occurs at times and locations characterized by model residence times in excess of 35 d. The results are discussed in the context of fish population regulation theory, particularly the member/vagrant hypothesis and the concept of abundance-dependent vagrancy. 相似文献
8.
Haddock (Melanogrammus aeglefinus L.) were maintained on either simulated natural (SNP) or advanced, phase‐shifted photoperiods (ADV) and reproductive characteristics of female fish were measured throughout two reproductive cycles. By advancing the seasonal photoperiod 8 weeks, relative to ambient conditions, follicle development, peak levels of estradiol and initiation of spawning were all accelerated compared with fish maintained on an SNP. Profiles of steroid synthesis and follicular development were similar between the two groups but the spawning period was protracted by 40 days in the fish maintained on ADV. Ultrasound imaging proved to be an effective and non‐invasive tool for accurately assessing ovarian development throughout the reproductive cycle. These results suggest that photoperiod manipulation has significant potential for extending the availability of eggs and larvae for haddock aquaculture. 相似文献
9.
Juvenile haddock, Melanogrammus aeglefinus L. (initial weight, 13.5 ± 0.1 g) were fed practical diets containing digestible protein to digestible energy (DP DE?1) ratios of 25–30 g DP MJ DE?1as‐fed using three protein levels (450, 500 and 550 g kg?1) each at two lipid levels (110 and 160 g kg?1) for 63 days. The results showed mean weight gain and feed conversion ratio were highest for diets containing 28.5 and 30.2 g DP MJ DE?1. DP DE?1 ratio had no significant effect on protein efficiency ratio except at the lowest level (24.7 g DP MJ DE?1) indicating a protein sparing effect of higher lipid when dietary protein is below the requirement. Haddock appears to preferentially use protein as the prime source of DE. DP DE?1 ratio had little effect on apparent digestibility (AD) of protein while AD of lipid was significantly affected. Significant differences in AD of energy and organic matter were found to be inversely related to the carbohydrate level of the diet. DP DE?1 ratios of 28.5 g DP MJ DE?1 or lower resulted in significantly higher hepatosomatic indexes. The highest whole‐body nitrogen gains and energy retention efficiencies were achieved at 28.5 and 30.2 g DP MJ DE?1, whereas only slight differences in nitrogen retention efficiencies were observed. The highest levels of energy retained in the form of protein were achieved at 28.5 and 30.2 g DP MJ DE?1. The diet that provided the best growth, feed utilization and digestibility with minimal HSI contained 546 g kg?1 protein (513 g kg?1 DP), 114 g kg?1 lipid, 164 g kg?1 carbohydrate, 17.0 MJ kg DE?1 and a DP DE?1 ratio of 30.2 g DP MJ DE?1. 相似文献
10.
We examine the hypothesis that recruitment is more variable in populations on isolated offshore banks than nearby shelf populations. Recruitment of cod (Gadus morhua) and American plaice (Hippoghssoides plates-soides) on Flemish Cap is more variable than in any comparable population. Recruitment of haddock (Melanogrammus aeglefinus) on Rockall Bank is also more variable than in surrounding populations. These results are confirmed both by estimates obtained by virtual population analysis and by research surveys. Recruitment of haddock and herring (Clupea harengus) on Georges Bank is also more variable than in surrounding populations; however, the results for two other groundfish populations, cod and yellowtake flounder (Limanda ferruginae), on Georges Bank are ambiguous. We conclude that marine fish populations on isolated banks are more variable than those on nearby shelf regions. 相似文献