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1.
Tetsuro Shiraishi Kumiko Okamoto Michio Yoneda Takeshi Sakai Seiji Ohshimo Shizumasa Onoe Akihiko Yamaguchi Michiya Matsuyama 《Fisheries Science》2008,74(5):947-954
The age and growth of chub mackerel Scomber japonicus collected from the East China Sea and the northern waters off Kyushu between June 2000 and June 2001 were determined by observing
the otolith surface after dipping it in xylene. The translucent and opaque zones on the otolith surface were identified, and
the number of translucent zones was counted. Monthly changes in the frequency of fish with translucent zones on the otolith
margin, and in the marginal increments, indicated that the translucent zones were formed between April and June. The seasonal
pattern of annulus formation on the otolith became clear by observing the otoliths of fish with known ages, and the otolith
formation in wild fish was consistent with that of fish with known ages. The mean gonadosomatic index of male and female fish
was high from March to May, and spawning females were observed from mid-March to mid-May. The estimated ages were 1–5 years
for males and 1–6 years for females. The von Bertalanffy growth parameters did not significantly differ between male and female.
The model was obtained as FL
t=406×{1−exp[−0.372×(t+1.68)] 相似文献
2.
The age and growth of two Nematalosa species around Okinawa Island were examined using sectioned otoliths collected from September 2003 to April 2006. Monthly
changes in the frequency of the appearance of a translucent band on the outer margin of the otoliths indicated that ring formation
occurred once a year from January to July for Nematalosa come and from January to March for Nematalosa japonica. The von Bertalanffy growth equations for both species were as follows: N. come: L
t
= 365.5{1 − exp[−0.111 × (t + 0.288)]} for females and L
t
= 214.7{1 − exp[−0.700 × (t – 1.110)]} for males; N. japonica: L
t
= 205.1{1 − exp[−1.068 × (t − 1.180)]} for females and L
t
= 195.5 {1 − exp[−1.293 × (t − 1.269)]} for males. The maximum ages observed for N. come and N. japonica were 11 and 6 years old, respectively. The growth of these species was characterized by the slow growth of N. come over many years, resulting in a larger size than N. japonica. 相似文献
3.
Takeshi Sakai Michio Yoneda Tetsuro Shiraishi Muneharu Tokimura Hiroshi Horikawa Michiya Matsuyama 《Fisheries Science》2009,75(4):895-902
We studied the age and growth of the lizardfish Saurida elongata using ground thin sections of otoliths (sagittae) from specimens collected in the Tsushima/Korea Strait between May 1999
and June 2001. A total of 695 individuals with fork lengths (FL) ranging from 189 to 478 mm were examined. The frequency of
translucent zone occurrence at the outer margin of the otoliths indicated that translucent zones formed once a year between
November and February. Most of the males examined were estimated to be 2–7 years old and the females, 3–9 years old. The maximum
estimated age of a male specimen was 10 years and that of a female, 11 years. The estimated von Bertalanffy growth curves
were FL
t
= 451{1 − exp[−0.172(t + 2.50)]} and FL
t
= 515{1 − exp[−0.151(t + 2.47)]} for males and females, respectively. At all ages, the FL at a specific age for females was greater than that for
males, suggesting that females of this species grow faster than males. 相似文献
4.
Jeong-Hoon Lee Keita Kodama Gen Kume Masaaki Oyama Satoshi Katayama Yuji Takao Toshihiro Horiguchi 《Fisheries Science》2009,75(2):379-385
To find an appropriate method for age determination in the marbled sole Pseudopleuronectes yokohamae in Tokyo Bay, Japan, sagittal otoliths of 1,343 individuals were observed by surface-reading and cross-section methods and
the results were compared. Opaque zones occurred once a year and were regarded as annuli in both methods. The surface-reading
method sometimes provided a lower count of the number of annuli than the cross-section method, and the frequency of this discrepancy
was highest in older fish (males above 5 years, females above 4 years). The oldest female fish was estimated to be age 10 years
by the cross-section method but 8 years by the surface-reading method. The cross-section method could provide a more accurate
estimate of age and is therefore likely to be indispensable to estimations of longevity. In contrast, the surface-reading
method is superior in terms of cost and time efficiency but is likely to underestimate the ages of older fish. However, growth
equations based on age estimated by the surface-reading method were sufficiently accurate if males ≥5 years and females ≥4 years
were combined as specific, single age groups of 5+ and 4+, respectively. 相似文献
5.
A total of 518 Gerres sp. were collected around Okinawa Island, Japan, from November 2002 to July 2005, with monthly sampling where the standard
length of females (n=218) were 56.2–147.1 mm, and males (n=149) were 62.2–139.4 mm. The maximum ages observed for females were 5+ years and males were 4+ years, estimated by transverse sectioned sagittal otoliths. Mean marginal increment indicated that opaque rings were formed
once a year during April to July. The standard length (SL; mm) — body wet weight (BW; g) relationships were described as BW=(3.26×10−5) SL2.97 and BW=(3.13×10−5) SL
2.98 for females and males, respectively, and the standard length at age described by von Bertalanffy growth function for females,
L
t=137.1(1−e−0.80[t+0.80]) and males, L
t=127.3(1−e−0.82[t+0.93]). 相似文献
6.
Tamaki Shimose Toshiyuki Tanabe Kuo-Shu Chen Chien-Chung Hsu 《Fisheries Research》2009,100(2):134-139
Age determination of wild captured Pacific bluefin tuna, Thunnus orientalis, was conducted using sagittal otoliths of 806 specimens (47–260 cm in fork length) caught in the waters off Japan and Taiwan. Otoliths were transversely sectioned and the opaque and translucent zones were analyzed. Opaque zones mainly appeared on the otolith edge from April to July, indicating that the opaque zone is formed annually. The opaque zones formed during later life (age 10+) were more distinct than the earlier zones. The estimated ages of specimens ranged from 1 to 26 years. Parameters of the von Bertalanffy growth function were estimated to be 249.6 cm, 0.173, and −0.254 years for L∞, k, and t0, respectively. Growth of younger fish was rapid up to 5 years old attaining about 150 cm, and then growth rate decreased. After that, fish attained about 200 cm at 9 years old and about 225 cm (90% of L∞) at 13 years old (50% of maximum age). This paper updates the biological information on length at age with a large size range to support stock assessment model analyses for this commercially valuable species. 相似文献
7.
Hongxia Liu Meiqin Yi Xueyan Shi Pei Liang Xiwu Gao 《Fish physiology and biochemistry》2007,33(1):29-34
The substrate specificity of brain acetylcholinesterase (AChE) in adult Carassius auratus fish and its sensitivity to carbamate insecticides were investigated in vitro. The results showed that the order of four
substrates hydrolyzed by brain AChE in C. auratus was acetylthiocholine iodide > β-methylthiocholine iodide > propionylthiocholine iodide > butyrylthiocholine iodide, and
the maximum velocity (V
max) of AChE hydrolyzing acetylthiocholine iodide (ATCh) was the highest among the four substrates, and the V
max values were 0.067 and 0.082 mmol min−1 mg−1 for male and female fish respectively. But their Michaelis–Menten constants (K
m) were the lowest, only 0.071 and 0.072 mmol/l respectively. Compared with other carbamate insecticides, the sensitivity of
brain AChE to carbofuran was the highest and the IC50 values were 1.04 × 10−6 mol/l for females and 1.17 × 10−6 mol/l for males. The inhibitory tendencies of eserine, methomyl, and aldicarb to brain AChE were very similar, and the percentage
inhibition increased with time at the concentration of 1 × 10−6 mol/l. The order of inhibition potential of the three inhibitors from the highest to the lowest was eserine, aldicarb, and
methomyl. 相似文献
8.
Kyoko Suzuki Tomoyasu Yoshitomi Yoichi Kawaguchi Masaki Ichimura Kaneaki Edo Tsuguo Otake 《Fisheries Science》2011,77(3):313-320
Sakhalin taimen Hucho perryi populations have decreased drastically to near extinction. It is urgent to establish an effective conservation strategy based
on an understanding of the characteristics of migration and habitat use of this species. We examined the migration history
of anadromous Sakhalin taimen captured off the Sarufutsu coast, northern Hokkaido, Japan, using otolith Sr:Ca ratios and also
examined the relationship between their otolith Sr:Ca ratios during freshwater and seawater residence in a rearing experiment.
Otolith Sr:Ca ratios of some fish from the Sarufutsu coast showed freshwater levels (0.5–4.0 × 10−3) near the core, which thereafter increased to brackish water levels (4.0–6.0 × 10−3), and then to seawater levels (6.0–10.0 × 10−3) in the outermost regions. Those findings indicate that specimens from the Sarufutsu coast migrated to the brackish water
region or the sea and spent most of their lives there. The anadromous migration pattern including the timing of downstream
migration seems to be flexible among individuals in the species. They migrate between freshwater and seawater or brackish
water several times during their lives, showing extensive habitat use. It is essential to secure the continuity among the
freshwater, brackish water, and seawater areas for their effective conservation. 相似文献
9.
Pietro Ceccuzzi Genciana Terova Fabio Brambilla Micaela Antonini Marco Saroglia 《Fisheries Science》2011,77(4):533-545
No data have previously been reported on Eurasian perch Perca fluviatilis L. in Lake Varese. In this study, the growth, diet, and reproductive biology of the Eurasian perch population were investigated
with the aim of providing information that may serve as a basis for efficient resource management. A total of 240 specimens
were caught during the monthly sampling campaign from November 2006 through October 2008. The length-to-weight relationships
were W
t = 8.4 × 10−3
L
t3.10 (males) and W
t = 4.1 × 10−3
L
t3.36 (females). The parameters for the von Bertalanffy growth function for pooled sexes were L
∞
= 33.17 cm, k = 0.20 year−1, and t
0 = −1.34 year. Perch in Lake Varese spawn from April through May. Sexual maturity is reached when males are 2 years old, in
females mostly when they are 3 years old. Relative fecundity (F
rel) and absolute fecundity (F
abs) were assessed for females. Fecundity values were similar to data reported for other European populations: females of age
2+ F
rel = 102,457 ± 12,275, age 3+ F
rel = 131,767 ± 5,891, and age 4+ F
rel = 131,252 ± 15,555. Perch diet spectrum was wide and somewhat characterized by season. Perch in Lake Varese feed on macroinvertebrates,
mainly Chironomidae and Chaoborus, zooplankton, and juvenile rudd Scardinius erythrophthalmus. 相似文献
10.
Effect of temperature on the development of eggs of round herring Etrumeus teres was experimentally examined to construct a temperature-dependent egg development model. Mature fish were collected in the
field and their eggs were artificially fertilized onboard. The eggs were incubated at nine temperatures set between 14.0 and
25.0°C. All eggs at the lowest three temperatures, 14.0°C, 15.0°C, and 16.0°C, ceased development and died at various stages
before hatching. Durations required to hatching after fertilization ranged from 38.0 h at 25.0°C to 90.0 h at 17.5°C. The
temperature-dependent egg development model, i.e., egg age in hours (y
i,t
) at the ith stage and temperature t (°C), was expressed as: y
i,t
= 4.604 × exp(−0.100 × t −0.129 × i) × i
2.593. From the application of the model to early-stage eggs collected in the field, it is concluded that round herring starts
spawning immediately after sunset and almost completes spawning by midnight. The temperature-dependent egg development model
and the daily pattern of spawning presented in this study are essential tools for developing the daily egg production method
to estimate the spawning stock biomass. 相似文献
11.
Bacillus circulans PB7, isolated from the intestine of Catla catla, was evaluated for use as a probiotic supplement in the feeds for the fingerlings of Catla catla. The effect of supplement on the growth performance, feed utilization efficiency, and immune response was evaluated. Catla
fingerlings (ave. wt. 6.48 ± 0.43 g) were fed diets supplemented with 2 × 104 (feed C1), 2 × 105 (feed C2), and 2 × 106 (feed C3) B. circulans PB 7 cells per 100 g feed for 60 days at 5% of the body weight per day in two equal instalments in triplicate treatments.
The control feed (CC) was not supplemented with the B. circulans. All the feeds were isocaloric and isonitrogenous. Fish fed with feed C2 displayed better growth, significantly (P ≤ 0.05) highest RNA/DNA ratio, a lower feed conversion ratio (FCR), and a higher protein efficiency ratio (PER) than the
other experimental diets. Highest carcass protein and lipid was also observed in the fish fed C2 feed compared to the others.
Significantly (P ≤ 0.05), highest protease was recorded in fish fed feed C2 (47.9 ± 0.016) and lowest in fish fed feed C3 (32.10 ± 0.009),
where α-amylase activity did not differ significantly (P ≤ 0.05) beyond the lowest inclusion level. ALP, ACP, GOT, and GPT in the liver of Catla catla were the highest (P ≤ 0.05) in fish fed C2 feed. The highest TSP, albumin, and globulin was observed in fish treated with C2 feed after 60 days
feeding trial, but the lowest glucose level was observed in the same treatment. After the feeding trial, the non-specific
immunity levels and disease resistance of fish were also studied. Phagocytic ratio, phagocytic index, and leucocrit value
were the highest in fish fed feed C2. After the feeding trial, the fish were challenged for 10 days by bath exposure to Aeromonas hydrophila (AH1) (105c.f.u. ml−1 for 1 h, and, after 7 days, 107c.f.u. ml−1 for 1 h). Highest survival percentage was observed in fish fed with feed C2 compared with only 6.66% in the controls, which
indicated the effectiveness of B. circulans PB 7 in reducing disease caused by A. hydrophila. 相似文献
12.
Gao Zexia Wang Weimin Yang Yi Khalid Abbas Li Dapeng Zou Guiwei James S. Diana 《Fish physiology and biochemistry》2007,33(3):213-222
The peripheral blood cells of one-year-old Chinese sturgeon (Acipenser sinensis) have been studied by light microscopy and transmission electron microscopy. The erythrocyte count was 84.86 × 104 cell mm−3 in the peripheral blood of the fish and that of leukocytes was 2.24 × 104 cell mm−3. The erythrocytes and four main types of leucocyte—thrombocytes, lymphocytes, granulocytes (including neutrophils and eosinophils),
and monocytes, were identified in the peripheral blood. In addition to normal erythrocytes, reticulocytes and division of
erythrocytes were observed. Thrombocytes were the most numerous among the leukocytes, and the number of neutrophils with lobated
nuclei was larger than for other fish. The structures of the erythrocytes, lymphocytes, monocytes, granulocytes, and thrombocytes
of the fish were studied. The erythrocytes were almost completely devoid of organelles, except for some mitochondria and granules.
A large number of vacuoles and a few organelles were observed in cytoplasm of the monocytes. There were many microvilli on
the membrane and pseudopodia-like cytoplasm bulge in the lymphocytes. The neutrophils were round or oval in shape with bilobed,
trilobed, or multilobed nuclei whereas the eosinophils had big special granules, dark stained. There were many vesicles in
some thrombocytes, which were related to its phagocytosis; some thrombocytes had almost no cytoplasm or organelles. 相似文献
13.
Otolith microchemical analyses of the strontium (Sr) and calcium (Ca) concentrations in the eels Anguilla japonica and A. anguilla caught in Tokyo Bay were undertaken to reconstruct the eels’ migratory histories. A. japonica in the yellow stage (immature stage) were caught in a bay without any adjacent rivers or streams. A. anguilla was in the silver stage (early maturing stage), and the eel was confirmed to have just begun spawning migration to the open
ocean from Tokyo Bay based on the otolith Sr:Ca ratios, which showed a typical catadromous life history with low Sr:Ca ratio
values throughout the eel’s life after recruitment. The mean Sr:Ca ratios in A. japonica from the elver mark to the otolith edge indicated the eels belonged to several general categories of migratory histories,
including sea eels (average Sr:Ca ratio ≥6.0 × 10−3) and estuarine eels (average Sr:Ca ratio 2.5 to 6.0 × 10−3) based on the criteria reported previously in A. japonica. All eels had a certain freshwater life period, although the period was highly variable among fish. These results indicate
that A. japonica has a flexible pattern of migration, with the ability to adapt to various habitats and salinities. 相似文献
14.
The effect of stocking density on the survival and growth of pikeperch, Sander lucioperca (L.), larvae was examined in two consecutive experiments. In experiment I, 4-day-old larvae [body wet weight (BW): 0.5 mg;
total body length (TL): 5.6 mm] were reared in 200-l cylindro-conical tanks in a closed, recirculating system (20 ± 0.5°C)
at three stocking densities (25, 50 and 100 larvae l−1) and fed a mixed feed (Artemia nauplii and Lansy A2 artificial feed) for 14 consecutive days. At densities of 25 and 100 larvae l−1, growth rate and survival ranged from 2.7 to 1.9 mg day−1 and from 79.2 to 72.3%, and fish biomass gain ranged from 0.6 to 2.0 g l−1, respectively. There were two periods of increased larval mortality: the first was at beginning of exogenous feeding and
the second during swim bladder inflation. In experiment II, 18-day-old larvae (BW: 35 mg; TL: 15.6 mm) obtained from experiment
I were reared under culture conditions similar to those of experiment I, but at lower stocking densities (6, 10 and 15 larvae
l−1). The fish were fed exclusively with artificial feed (trout starter) for 21 consecutive days. At densities of 6 and 15 larvae
l−1, the growth rate and fish biomass gain ranged from 28.8 to 23.1 mg day−1 and from 2.0 to 3.3 g l−1, respectively. The highest survival (56.5%) was achieved at a density of 6 larvae l−1. Mortality at all densities was mainly caused by cannibalism II type behaviour (27–35% of total). In both experiments, growth
and survival were negatively correlated and fish biomass gain positively correlated with stocking densities. The present study
suggests that the initial stocking density of pikeperch larvae reared in a recirculating system can be 100 individuals l−1 for the 4- to 18-day period post-hatch and 15 individuals l−1 for the post-19-day period. 相似文献
15.
Largemouth perch (Percichthys colhuapiensis) represents one of the most economically important fish species in the Argentine Patagonia. However, little research has been done on the age and growth and population dynamics of this fish, though both studies are essential to properly deal with fisheries forecasts and management. As a contribution to elaborating management programmes for P. colhuapiensis, we evaluated the age and growth of this species in the Negro river via scale and whole otolith reading methods. The sample consisted of 579 specimens ranging in total length (TL) from 90 to 475 mm, captured seasonally from December 1994 to December 1995. The formation of scale annuli (end of winter) and the hyaline zone on otoliths (winter) of adult fish coincided with the beginning of the spawning season (end of winter-beginning of spring). The maximum estimated age was 11 years, which indicates that this is a relatively long-lived species. Otoliths were useful for ageing specimens 1–5 years-old, but above this age whole otoliths yielded lower age estimates than scales. Isometric growth of weight with length was found for total population, juveniles, and separate sexes (p > 0.25 in all cases). No significant differences between the length–weight relationships of sexes were observed (p > 0.10). Length at first maturity was significantly higher for males (TL50 = 271 mm TL; r = 0.88) than for females (TL50 = 243 mm TL; r = 0.96) (p < 0.01). Largemouth perch exhibited a consistent pattern of increase in length with age, with a period of fast growth during the first 5 years, and a slow-growing phase during the rest of his life. The growth parameters based on scale data were L∞: 462.1 mm, k = 0.23 and t0 = −0.94 for total population, L∞: 402.3 mm, k = 0.33 and t0 = −0.67 for males, and L∞: 548.4 mm, k = 0.15 and t0 = −1.59 for females, whereas those based on otolith reading were L∞: 537.4 mm, k = 0.17 and t0 = −1.0 for total population, L∞: 497.6 mm, k = 0.21 and t0 = −0.79 for males, and L∞: 582.0 mm, k = 0.14 and t0 = −1.53 for females. Scales are concluded to be the best structure to age P. colhuapiensis because they rendered L∞ values closer to the maximum TL observed, high precision, easiness of collection, low processing time, and the possibility of performing non-destructive monitoring studies. 相似文献
16.
In this study, we have investigated the effects of Porphyridium cruentum (Rodophyta) as a natural pigment source and astaxanthin and β-carotene as synthetic pigment sources on the skin colour of
cichlid fish (Cichlasoma severum sp., Heckel 1840), which are generally light orange with white patches and becomes shiny orange in the reproductive phase.
The fish were fed diets containing 50 mg kg−1 astaxanthin and β-carotene, and P. cruentum powder. The amount of both natural and synthetic pigment sources given as feed was 50 mg kg−1, and the experiment was continued for 50 days. Total carotenoid content of the fish was determined spectrophotometrically
at the end of the experiment. As a result, while a visible change of colour in the skin of the fish fed on the feed containing
astaxanthin was observed with 0.34 ± 0.2 mg g−1 of pigment accumulation, a relatively small change of colour was observed in the skin of other fish that were fed on the
feed containing P. cruentum and β-carotene with 0.22 ± 0.2 mg g−1 and 0.26 ± 0.1 mg g−1 of pigment accumulations, respectively. Therefore, it was determined that these pigment sources have an effect on the colour
of cichlid fish. 相似文献
17.
Bacillus subtilis isolated from the intestine of Cirrhinus mrigala (Hamilton) was incorporated into the rearing water of Poecilia reticulata (Peters), Poecilia sphenops (Valenciennes), Xiphophorus helleri (Heckel) and Xiphophorus maculatus (Gunther) at four different concentrations (5 × 108 cells ml−1, 5 × 107 cells ml−1, 5 × 106 cells ml−1 and 5 × 105 cells ml−1) and its effect on fish growth performance and survival, water quality parameters and bacterial population of water were
assessed. The results showed that the addition of bacterial cells in the rearing water resulted in greater survival and a
faster growth rate and, hence, greater length and weight increments of the livebearers. The use of a bioaugmentor in the rearing
water of the livebearing fishes resulted in significantly lower (P < 0.05) concentrations of dissolved organic matter and total ammonium nitrogen. The counts of motile aeromonads and total
coliforms recorded in the water of bioaugmented tanks were also lower than that in the control tank. Bioaugmentation between
106 and 108 cells ml−1 in the rearing water is sufficient in establishing a bioaugmentor and the use of a higher concentration of bacterial cells
did not always lead to significantly better results. 相似文献
18.
We examined the formation of annuli by marginal observations on otoliths of gunnel (Pholis fangi) in the Yellow Sea to validate the age determination method and to derive the growth equation covering from larval to adult stages. Gunnels, ranging from 46 to 173 mm in total length, were collected by a bag net fishery from the western coastal waters off Korea from November 1998 to October 1999. Marginal observations indicated that the translucent zone (annual mark) on adult otolith was formed during the winter, whereas the opaque zone was formed during the summer. However, a translucent zone was formed between May and June in juvenile otoliths. This false ring was formed when the fish transited from the inshore pelagic life of larvae to the offshore bottom life of juveniles. The observed maximum age was 58 months. Using observed length-at-monthly age, growth in length was expressed by von Bertalanffy growth curve; Lt = 144.0 (1 − e−0.11 (t+0.43)). P. fangi spawned in winter recruit to inshore, and grow quickly in the nursery habitats in spring. Gunnel inhabit the bottom offshore area during the summer season, and reappear inshore thereafter. 相似文献
19.
Teleost fish lack the enzyme for endogenous synthesis of ascorbic acid (AA), an essential micronutrient for fish. The aim
of this study was to examine the effect of higher levels of dietary vitamin C on growth, nutritional quality, and immunomodulation
in the Indian major carp, rohu (Labeo rohita). Four groups of L. rohita were fed experimental diets containing either no vitamin C (control) or supplemented with vitamin C at 500 mg kg−1 (Exp-1), 1000 mg kg−1 (Exp-2), or 1500 mg kg−1 (Exp-3) for 60 days. Growth parameters (NWG, ADG, and SGR), serological parameters (TSP, TSA, TSG, and A:G), haematological
parameters (TLC, TEC, Hct, MCV, and MCH), and different non-specific immunological parameters (PR, PI, respiratory burst activity,
and bactericidal activity) were evaluated during the experimental trial. Fish fed a vitamin C-supplemented diet showed higher
specific growth rate (SGR) up to 1000 mg kg−1 compared with control fish. Different haematological and serological parameters along with non-specific immune parameters
were influenced by vitamin C supplementation. Among the non-specific immune parameters phagocytic activity (PR and PI) and
respiratory burst activity (NBT cells) were significantly (P ≤ 0.05) enhanced by increasing doses of vitamin C supplementation. Higher levels of dietary vitamin C significantly (P ≤ 0.05) enhanced protection against Aeromonas hydrophila (AH1) infection compared with controls. Results from this study help to establish the beneficial effect of vitamin C on growth
and immunmodulation in rohu (L. rohita). 相似文献
20.
The growth, sex ratio with age, and age at sexual maturation were determined based on sectioned otoliths in 257 specimens
of the blackspot tuskfish Choerodon schoenleinii collected in waters off Ryukyu Island. Opaque rings observed by reflected light in the sectioned otoliths were found to form
once a year from January to July. The three growth parameters of the von Bertalanffy growth equation were L∞ = 68.1 (cm), k = 0.263, and t
0 = −0.023 (year). The age at which the sex ratio reached 50% by sexual transition was about 6.15 years, and the age at which
50% of females were sexually mature was approximately 2 years. The oldest specimen among the samples was 17 years old. 相似文献