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1.
A study of gonad development and spawning in Anadara granosa (L.) from the west coast of West Malaysia was carried out between September 1977 and November 1978 based on (a) changes in the condition of the whole animal and (b) histological changes in the gonad. Gonads did not develop until a length of 17.5 mm had been attained and the first spawning probably occurred at a length of 24–25 mm. There was evidence of a low level of spawning activity throughout the year but the largest size group spawned in October in 2 consecutive years. There was inconclusive evidence for a second spawning in May/June. A condition index of dry/wet weight of tissue adequately reflected spawning in specimens longer than 30 mm. There was no deviation from a 1 : 1 ratio of males to females in any of the size classes studied. 相似文献
2.
Variation in growth rate,liver weight and body composition at first sexual maturity in rainbow trout
Bjarte Tveranger 《Aquaculture (Amsterdam, Netherlands)》1985,49(2):89-99
Rainbow trout around 743 g were fed four different diets over an 8-month period. Maturing males grew faster in the period before spawning (Sept.–Dec.) than maturing females, and significantly faster than immature fish. Mature fish stagnated in growth while the immature fish surpassed the growth of mature fish during the spawning season. The condition factor was moderately influenced by the maturation process. In the period before spawning (Sept.–Jan.) maturing females had a significantly higher hepatosomatic index than males and immature fish. An increase in dry matter and fat and a decrease of protein were observed in the muscle of maturing males and immature fish towards the spawning season, while maturing females had a slight fall in dry matter and fat and a small increase in protein in the same period. Dry matter and fat in muscle of rainbow trout were positively correlated. 相似文献
3.
Early sexual maturation of male chinook salmon (maturation 1 to 4 years prior to females in the same age class) results in reduced effectiveness of stock enhancement programs and a financial loss to the salmon farming industry. Previous studies in Atlantic salmon have shown that the age of maturity in males is affected by growth and/or body energy stores, but the relative roles of these two factors are not well understood. Therefore, an experiment was designed to determine when spermatogenesis was initiated, to characterize the endocrine changes during the onset of puberty in male salmon, and to determine if the level of whole-body lipid affects the incidence of early male maturation in a wild stock (Yakima River) of 1+ spring chinook salmon. Fry were fed a commercial diet from February until August and were then divided into groups of 320 fish (mean weight, 5.6 g) and fed one of five experimental diets (two replicate groups/diet) containing 4%, 9%, 14%, 18% or 22% lipid and 82%, 77%, 73%, 69%, or 65% protein for 13 months. Fish were reared on natural photoperiod and ambient temperature (6°C to 16°C), and pair-fed to a level based on the tank with the lowest feed consumption. Fish were weighed monthly and sampled to determine body composition, pituitary follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels, plasma insulin-like growth factor I (IGF-I) levels, and stage of gonadal development.
Throughout the experimental period the mean fish weight was similar among treatment groups. However, from December through the end of the experiment in the following September, maturing males were significantly larger than nonmaturing fish. Initial lipid levels in 0-age experimental fish were near 6%, which is similar to wild fish of the same stock and age captured in the Yakima River during August. Fish fed diets containing more than 4% lipid increased in whole-body lipid content during the first 2 months of feeding and then maintained at relatively constant levels during the course of the experiment. Whole-body lipid levels for the dietary treatment groups averaged 5.6%, 7.1%, 8.2%, 9.4%, and 9.6% from October through the following September.
Based on histological examination of the testes of experimental fish, type B spermatogonia and primary spermatocytes were first observed in some of the yearling males during November. These were designated maturing males. Pituitary FSH levels were significantly higher in maturing than nonmaturing males at this time and for the remainder of the study. Pituitary FSH levels increased as spermatogenesis proceeded in maturing fish, whereas pituitary LH levels increased in maturing 1+ males only during July and August, when testes were in late stages of spermatogenesis and in September during spermiation. Plasma IGF-I levels were significantly higher in maturing males than nonmaturing fish from December through the end of experiment. Since maturing males were significantly larger than nonmaturing fish of both sexes from December through September, the difference in IGF-I levels could be due to differences in growth or due to maturation.
The percentage of maturing males was significantly influenced by whole-body lipid, increasing from 34% in fish fed the 4% lipid diet to 45% in fish fed the 22% lipid diet. These data suggest that whole-body lipid levels influenced the incidence of maturation of male spring chinook salmon. In addition, both endocrine and histological indicators suggest that maturation was initiated in males approximately a full year prior to the time the fish will spawn. 相似文献
4.
5.
Changes in condition factor (cf) and gonadosomatic index (GSI) in maturing and non‐maturing Atlantic salmon (Salmo salar L.) cultured in Bay of Fundy sea cages was investigated under control (natural) and continuous light conditions. All experimental cages contained salmon stocked as smolts in April 2001. Six control cages received only natural illumination, three received continuous light from 3 November, 2001 until 31 May, 2002, and three received continuous illumination from 15 February, 2001 until 31 May, 2002. In mid‐July 2002, each cage was sampled, and sex, round weight, fork length (FL), mean muscle lipid content and gonad weight were recorded from each sampled fish. At harvest (August 2002 to February 2003), sex, maturation state, round weight and FL were measured from a sample of fish from each cage. The frequency distributions of GSIs from fish sampled in July indicated for both sexes a GSI>0.3 was indicative of early maturation. The relationship between cf and GSI suggested that salmon of both sexes had to have a cf greater than 1.3 in early summer for early maturation to develop. Continuous illumination from November greatly reduced the number of males with GSI>0.3 in mid‐July (0.8%, compared with 50% for control males); 17% of males from cages lit in February had GSIs exceeding 0.3. The percentage of control females exceeding 0.3 was 7%, compared with 0% and 4% for females from cages receiving continuous illumination from November and February respectively. For salmon with GSI of 0.3 or less, the percent muscle lipid increased linearly with cf. A multiple regression of cf and FL on GSI (GSI=?0.973+0.35 cf+0.013 FL) correctly identified 88% of maturing vs. non‐maturing salmon from control cages in July. 相似文献
6.
L. Garcia-Rejón M. J. Sanchez-Muros J. Cerdá M. de la Higuera 《Fish physiology and biochemistry》1997,16(2):93-105
The fructose 1,6 biphosphatase (FBPase) activity was measured in the liver and gonads of broodstock sea bass that were fed
three experimental diets over the reproductive cycle. Enzyme activity was measured at the pre-spawning (November), spawning
(February) and post-spawning (May) periods. Additionally, some biometric indices were calculated at these three times. The
different diets, one with standard composition (51% protein, 13% lipid, 10% digestible carbohydrates), one with a high-carbohydrate
content (32% protein, 13% lipid, 32% digestible carbohydrates) and one deficient in ω3 essential fatty acids (51% protein,
13% lipid, 10% digestible carbohydrates), had similar affects on growth and gonad development, as deduced from the similar
weight, condition factor, hepatosomatic index, gonadosomatic index and liposomatic index over the reproductive cycle. FBPase
activity was detected at all times in the liver of both sexes, and in the ovaries but not in the testes. In general, females
showed greater liver activity than males, especially at spawning time. During post-spawning, FBPase activity fell in tissues
of both sexes. Enzyme activity was also affected, mostly in the liver, by the different types of feed; hepatic activity in
fish fed the high-carbohydrate diet fell during the spawning and post-spawning periods, though at a different level for each
sex. The diet deficient in ω3 EFA presented the lowest FBPase activity, compared with the other diets, in females during the
spawning period; there was very little change in males or females over the reproductive cycle. The results showed that the
highest gluconeogenic activity in sea bass broodstock occurred at the spawning time and the females had larger glucose requirements
than males over the reproductive cycle, as demonstrated by the absence of FBPase activity in testes. This work also confirmed
the adaptative capacity of this enzyme to different nutritional and physiological conditions. 相似文献
7.
Regin Arge Magny S Thomassen Rolf K Berge Jose L Zambonino‐Infante Bendik Fyhn Terjesen Maike Oehme Kjell‐Arne Rørvik 《Aquaculture Research》2014,45(5):922-933
Effects of dietary tetradecylthioacetic fatty acid (TTA) on muscle fat, development of gonads and early sexual maturation in S0 Atlantic salmon during the first year in sea were investigated. TTA (0.5% w/w) was added to the feeds for 8 weeks in the spring. In May, at the end of the TTA‐feeding period, the fish in the TTA group had significantly (P < 0.05) less fat (10.1%) stored in muscle compared with the control group (10.8%). In September, mean male gonadosomatic index (GSI) in maturing fish in the TTA group was found to be lower compared with the maturing fish in the control group (P = 0.05). On the basis of GSI values, male sexual maturation in September was 10.0% vs. 14.4% for the TTA and the control group respectively. Thus, relative to the control group, the incidence of male sexual maturation in the TTA group was reduced by about 1/3 (P = 0.002). Production data was not affected by dietary supplementation of TTA. This study reveals that TTA significantly reduces the incidence of male sexual maturation in S0 Atlantic salmon. A significant elimination model of TTA in fish muscle that takes into account, the growth rate of the fish was further developed in this study. 相似文献
8.
K. Uysal A. Yerlikaya M. Y. Aksoylar M. Yöntem M. Ulupinar 《Ecology of Freshwater Fish》2006,15(4):441-445
Abstract – We examined seasonal variations in liver condition factor, total lipid and fatty acid composition of maturing pikeperch ( Sander lucioperca) from Lake Eğirdir, Turkey. The spawning of pikeperch in Eğirdir Lake started in March, continued very fast during May and gradually ended in July as determined by measuring the gonadosomatic index. The total lipid content of male and female liver reached its highest level in September and November (the end of dense feeding period during which temperature decreased sharply), but declined to the lowest level in May (just after spawning). The highest level of liver condition factor was observed in January and March during which gonads mature rapidly. Palmitic acid was the predominant saturated fatty acid (SFA) in female and male liver. The ratio of monounsaturated fatty acids (MUFA) was higher than that of polyunsaturated fatty acids (PUFA) in both sexes. Docosahexaenoic acid (22:6 n -3), eicosopentaenoic acid (20:5 n -3) and arachidonic acid (20:4 n -6) were the predominant PUFA. Seasonal variations in PUFA were more evident than that in other fatty acids. PUFA, especially the n -3 fatty acids ratio, increased to the maximum level during the sharp decreases in temperature (in November). However, the amount of PUFA decreased to the lowest level in reproductive period. The results suggest that the ratio of pikeperch liver fatty acids is influenced by gonad maturation and temperature variations and that pikeperch requires a large amount of PUFA and the n -3 fatty acids for the development of gonads. 相似文献
9.
Chris M. C. Woods Philip J. James Graeme A. Moss Johnny Wright Sten Siikavuopio 《Aquaculture International》2008,16(1):49-68
We compared the gonad-enhancing effects of two diets (NIWA and NIFA diets) in two size classes of sea urchins (Evechinus chloroticus): small and large urchins with a test diameter of 75.6 ± 1.2 mm and 93.8 ± 0.5 mm, weighing 174.8 ± 7.9 g and 315 ± 5.6 g,
respectively. After eight weeks being fed prepared diets, urchin gonad index (GI) had significantly surpassed that of the
initial and final samples of wild urchins. Urchins in the NIWA/small treatment had a larger GI than the NIFA/small and NIFA/large
treatments. The NIWA/large treatment had a larger GI than the NIFA/large treatment. The overall percentage increase in GI
for the NIWA/small, NIWA/large, NIFA/small and NIFA/large treatments were 183%, 135%, 132% and 85%, respectively. In terms
of gonad colour (CIELAB), there were no significant differences in gonad redness (a*) or yellowness (b*) between experimental
treatments, but there was a significant difference in gonad lightness (L*) with small urchins fed both diets having lighter-coloured
gonads than the large urchins fed both diets. Sensory assessment of gonads revealed that gonads from small urchins fed both
diets were rated as being of better colouration and more uniform in colour than gonads from large urchins. Gonads of urchins
fed the NIFA diet were rated as being less bitter and of better overall taste than gonads from urchins fed the NIWA diet.
This study shows that feeding prepared diets to E. chloroticus can significantly increase gonad yield but that different diets can affect the magnitude of GI increase and the taste of
gonads, and that smaller urchins appear more suitable for gonad enhancement. 相似文献
10.
ABSTRACT: During 1986–1989, the seasonal maturation and gonad index (gonad weight/body weight × 100) of adult Loxechinus albus were examined at nine sites, and the appearance of four-armed echinopluteus larvae was investigated at three sites off the eastern coast of Chiloé Island, Chile. Spawning occurred during November–January when the gonad indices fell to a minimum, the number of mature specimens decreased and four-armed larvae appeared, corresponding to the rise in water temperature. The number of four-armed larvae appearing at the northern site was markedly less than that at the southern site. The sea urchins matured in January and February immediately after spawning at many sites and a high percentage of maturation lasted for a long period at some sites. These findings are considered to be associated with high food availability and annual narrow ranges of water temperature. 相似文献
11.
Tillmann J. Benfey Helen M. Dye Igor I. Solar Edward M. Donaldson 《Fish physiology and biochemistry》1989,6(2):113-120
This paper describes the effect of triploidy on growth and reproductive endocrinology in the months leading up to and including spawning in rainbow trout,Salmo gairdneri, and pink salmon,Oncorhynchus gorbuscha. Growth rates were the same for diploid and triploid rainbow trout, but triploid female pink salmon were smaller than maturing diploid females and diploid and triploid males of the same age. Triploid males of both species developed typical secondary sexual characteristics and had normal endocrine profiles, although their cycle appeared to be delayed by about one month. Triploid females remained silvery in appearance and showed no endocrine signs of maturation, even at the level of the pituitary. Thus, although triploids of both sexes are genetically sterile, only the females do not undergo physiological maturation.Reported in part at the Third International Symposium on Reproductive Physiology of Fish, St. John's, Newfoundland, August 2–7, 1987. 相似文献
12.
Yoshifumi Sawada Manabu Seoka Keitaro Kato Toshihiro Tamura Masahiro Nakatani Shoji Hayashi Tokihiko Okada Kenichi Tose Shigeru Miyashita Osamu Murata Hidemi Kumai 《Fisheries Science》2007,73(5):1070-1077
ABSTRACT: Stable reproduction is essential for supplying artificially hatched fish to tuna aquaculture. We observed testes maturation in reared Pacific bluefin tuna (PBT) Thunnus orientalis at 2+ years of age. The incidence of males with mature testes was 25.0%, and 40% of the males had developing testes that contain spermatozoa, while oocytes of the same aged females were not mature. These fish were wild-caught at 0+ years old in August 1997 and the gonads were examined in October 1998 and January–February 2000. Therefore, the age at examination in 2000 was estimated to be 2 years and 7–10 months old considering the spawning season of the wild PBT and the size when captured. Histological examination of the matured and developing testes showed that they contained spermatozoa, spermatids, spermatocytes, and spermatogonia. All the spermatozoa were observed to be motile in sea water under light microscopy. From the results of this and previous studies, matured males are probably fertile for at least 5 months a year in Kushimoto. The testes maturation observed at young age in captivity is considered promising to reduce the cost of broodstock maintenance for the juvenile production of PBT, especially if the sperm are cryopreserved. 相似文献
13.
Reproductive cycle of yellow sea bream <Emphasis Type="Italic">Dentex tumifrons</Emphasis> in Wakasa Bay,the Sea of Japan off central Honshu 总被引：2，自引：0，他引：2
ABSTRACT: To determine the spawning season and reproductive cycle of the yellow sea bream, Dentex tumifrons , in Wakasa Bay, in the Sea of Japan off central Honshu, seasonal change in the gonadosomatic index ( GSI ) was examined and histological observations of both ovaries and testes were conducted. The female GSI gradually increased from May, maintained a high level between August and October and then rapidly decreased. The histological observations of the ovary showed that vitellogenesis began from May and developed until September. Spent fish began to be observed in October and all the fish collected in December were spent. There was only one peak in the seasonal change in GSI of males and females in Wakasa Bay. Thus, yellow sea bream spawn only in autumn in Wakasa Bay. Differences in the reproductive cycle and number of spawning seasons were found between the two different latitudinal areas, Wakasa Bay and the East China Sea (low latitudinal area) where the spawning seasons were spring and autumn. An increase in water temperature is an important factor to initiate gonadal maturation (recrudescence) and is terminated by the short day-length in Wakasa Bay. 相似文献
14.
Tissue Lipid Content and Fatty Acid Composition of Penaeus monodon Fabricius Broodstock from the Wild 总被引：6，自引：0，他引：6
Oseni M. Millamena Felicitas P. Pascual 《Journal of the World Aquaculture Society》1990,21(2):116-121
Tissues (hepatopancreas, muscle, gonad) of wild Penacus mordon females with ovaries in different stages of development and males were analyzed for Upid content and fatty acid composition. Hepatopancreatic tissue had the highest mean levels of lipid at 15.72–25.20% in females and averaged 46.20 ± 1.53% in males. Levels of Lipid in the muscle were low with no marked variation throughout the maturation s-es. Ovarian lipid levels increased significantly at stage II (early maturing ovaries) and remained high through stage IV (fully mature ovaries). Peak lipid level was found at stage III (late maturing ovaries) and coincided with a decline in hepatopancreas lipid. Ovarian and hepatopancreatic lipids declined drastically in spent females. Profiles of fatty acid in the tissues consistently showed the presence of PUFA 204n-6, 20:5n-3 and 22611-3, with high levels in the polar lipid fraction of vitellogenic ovaries. These values were reflected in the male testis and spawned eggs. The finding suggest storage and utilization of lipids for maturation and spawning processes and that the phospholipids were mainly responsible for increases in ovarian lipids. The type of fatty acids present in maturing prawn ovaries is indicative of their importance in reproductive physiology. 相似文献
15.
Somatolactin (SL) is a novel pituitary hormone recently characterized in several fish species. Structural analyses have shown that SL belongs to the growth hormone/prolactin family, and that it is a highly conserved protein. SL is synthesized by the periodic acid/Schiff-positive cells in the pars intermedia, but has an as yet unidentified function(s). We have recently developed a homologous radioimmunoassay for coho salmon SL and measured plasma levels of SL during two stages of the coho salmon life cycle, smoltification and sexual maturation. During smoltification, plasma levels of SL changed almost in parallel with plasma levels of thyroxine; levels increased as morphological indices of smoltification appeared and decreased as smoltification was completed. Following this period, SL levels remained low until the spring prior to spawning. In a separate study, plasma levels of SL were measured in sexually maturing coho salmon that remained in fresh water throughout their life cycle. During the year of sexual maturation, plasma levels of SL gradually increased from the spring onward, reaching peak levels at the time of spawning in November and December. These data are similar to those previously reported for sexually maturing coho salmon that were maintained in seawater prior to spawning (Rand-Weaver et al. 1992). Therefore, increases in plasma SL levels occurred in sexually maturing fish irrespective of whether they were maintained in fresh water or seawater. Peak levels at spawning were higher than those observed during smoltification. Possible roles for SL in metabolism and reproduction are discussed. 相似文献
16.
The seasonal gonadal changes in the edible clam, Paphia laterisulca, from the Kalbadevi Estuary at Ratnagiri were studied for the period from May 1972 to April 1973 with the help of fresh gonad smears and histological study. The observations of gonad smears revealed the probable commencement of spawning between September and April from the occurrence of spent gonads. Male and female clams were present in almost equal numbers throughout the year.Histological details revealed that the clam P. laterisulca has a prolonged spawning period extending from mid-September to the end of March with two peaks, the first in October–November and the second in February–March. Lysis of the ripe gametes in both sexes for 2.5 months preceding spawning was observed. The second spawning peak was followed by regression in the gonads.Active gametogenesis was observed in May and June (33.5°C and 30.0°C), and again in December and January (21.5°C and 26.0°C) in clams that had spawned during the first spawning peak.The spawning stimulus in Paphia laterisulca appeared to be the sudden increase in salinity (from 4.1 to 22.5‰) in September in the Kalbadevi Estuary. 相似文献
17.
Antnio Fernando Gervsio Leonardo Elizabeth Romagosa Maria Inês Borella Sergio Ricardo Batlouni 《Aquaculture (Amsterdam, Netherlands)》2004,240(1-4):451-461
In the months of January 2001 and 2002, female cachara Pseudoplatystoma fasciatum were selected during their first and second gonadal maturation (2 years and 7 months old and 3 years and 7 months old, respectively) with an of oocyte diameter of 937.5 μm (82.5% with central nuclei and 17.5% with peripheral nuclei). Nine females in first maturation received two doses of carp pituitary extract (CPE), 0.5 mg/kg and 5.0 mg/kg; seven received two doses of human chorionic gonadotropin (hCG), 5 and 10 IU/g; five received doses of 0.5 CPE mg/kg and 5 hCG IU/g (CPE+hCG); and four received 0.9% saline (saline). Nine females from CPE and seven from hCG presented oocytes with the same diameter at the moment of oocyte release (100% with germinal vesicle breakdown and fertilization rate of 53.44±18.3 and 54.81±11.8%; larvae number of 165,330±94.1 and 158,570±20.6, respectively). The five females from CPE+hCG did not respond to the hormonal treatment. The four females from the saline group did not ovulate. In January 2002, 6 of 15 selected females that were going through the second reproductive cycle received CPE (five received hCG and four received saline), showing oocyte diameters similar to the ones in the first maturation. At stripping, CPE females had an oocyte diameter of 1062.5 μm (the hCG females had oocyte diameters ranging from 937.5 to 1125.0 μm; fertilization rates of 56.08±30.9 and 81.90±17.3%; 364,547±244 and 633,129±190, larvae, respectively). The fertilization rates and larvae number were higher in the second gonad maturation, both for CPE and hCG. 相似文献
18.
José Reyes-Tomassini 《Fish physiology and biochemistry》2013,39(4):993-1005
The manner in which behavior influences the gonadotropin-releasing hormone (GnRH) axis in hermaphroditic fishes is not understood. The Gilthead seabream, Sparus aurata, is a protandrous hermaphrodite with a complex gonadal cycle consisting of a quiescent, pre-spawning, spawning, and post-spawning stage. On two separate experiments, I used real-time quantitative PCR to measure the mRNA expression of three GnRH isoforms in homogenized seabream whole-brain extracts. In the first experiment, I measured the levels of GnRH-1, GnRH-2, and GnRH-3 mRNA throughout the gonad cycle. All three GnRH mRNAs increase around the peak of the spawning season (December). GnRH-3 mRNA expression is also elevated in August, which coincides with the beginning of gonad differentiation. All three GnRH mRNAs have the lowest expression levels in the month of September. There was no difference between males and females in the expression levels of any of the three GnRH mRNA. In the second experiment, I measured individual dominance ranks in six groups of fish, three during quiescence and three during spawning. GnRH-1 mRNA expression was positively correlated with dominance rank only during the quiescent period. The more dominant fish tended to have higher GnRH-1 mRNA expression. The existence of a quiescent-only correlation between GnRH-1 mRNA and dominance rank suggests a mechanism by which activation of gonad maturation could occur first in the most dominant ambisexual fish. 相似文献
19.
Hua Thai Nhan Truong Quynh Nhu Pham Minh Duc Hon Jung Liew Harry Ako Rajesh Jha 《Aquaculture Nutrition》2020,26(5):1771-1779
This study investigated the effect of dietary arachidonic acid (ARA, 20:4n‐6) on final maturation, spawning performance and composition of the gonad of black sea urchin (Diadema setosum). Four different dietary ARA levels of 0.3 g/kg (Control diet), 1.4 g/kg (ARA 1.4), 2.5 g/kg (ARA 2.5) and 3.7 g/kg (ARA 3.7) were prepared and tested in this feeding trial for 90 days. The result showed that growth in terms of weight was not relatively affected by dietary ARA. Gonadosomatic Index (GSI) of animals were gradually increased in all the diets throughout the trial. The highest GSI level (25.7 ± 3.16%) was observed in animals fed with the diet ARA 1.4. ARA content in the gonad proportionally increased with dietary ARA levels. The highest larval survival rate (85.5 ± 5.67%) was found in diet ARA 2.5. The results of this study indicate that ARA plays an important role in the reproduction functions of black sea urchin and supplementing an appropriate level of ARA in the broodstock diet could induce the final maturation and improve reproduction of black sea urchin, but a higher level of ARA (3.7 g/kg) seems to have a negative effect on both growth rate and GSI. 相似文献
20.
A K Imsland A Folkvord G L Grung S O Stefansson G L Taranger 《Aquaculture Research》1997,28(2):101-114
Sexual dimorphism in growth and maturation of individually tagged turbot (n= 421), Scophthalmus maximus Rafinesque, was studied in a long-lasting (20 months) growth experiment with four temperature regimes. The influence of onset of puberty and subsequent maturation on growth was evaluated. There were no initial size differences, but the final weight of females was larger than that of males at all temperature regimes, except at the lowest temperature. Surplus energy (sum of increase in somatic weight and gonad weight) in females was on average greater than in males from 8 months prior to first spawning. Significant growth (as specific growth rate, SGR) differences between maturing and immature fish were detected from the age of 9 months post hatch. Maturing females had the highest growth rate and reached the largest size (1.8 kg in 20 months), whereas male body weights reached a plateau and levelled off around 1.0 kg. To optimize production characteristics in turbot aquaculture and achieve more homogeneous growth, methods should be developed to produce all-female broods. 相似文献