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1.
Grading trials were performed in experimental and commercial catfish ponds to compare an in-pond horizontal floating bar grader to current live-car grading. Three replicate trials were conducted in experimental ponds at three different temperature ranges (warm, >26 °C; cool, 13–26 °C; cold, <13 °C) with catfish size groups stocked in ratios of either 75:25, 50:50, or 25:75 sub-marketable (<0.57 kg) to marketable fish (≥0.57 kg). Commercial pond trials were replicated three times at each temperature range with a fish size range typical of ponds ready to harvest. Stress experienced by fish during harvest and grading was measured by mean serum glucose and cortisol levels. Grading speed was greater (P < 0.05) with the UAPB grader (105–449 kg/min) than the traditional live-car grader (0.5–0.6 kg/min). The UAPB grader decreased (P < 0.05) the proportion of sub-marketable fish during all trials. In contrast, the live car did not reduce the proportion of sub-marketable fish with the experimental methods used in this study during commercial trials or in the 25:75 distributions during warm and cold temperature trials in experimental ponds. The UAPB grader returned an average two to four times (range of 2–52) more sub-marketable fish by weight to the pond than the traditional live car method. Glucose and cortisol levels in fish graded with the two technologies were not significantly different. The UAPB grader sorted fish more accurately, consistently, and quickly than the live car at all temperatures in both experimental and commercial trials.  相似文献   

2.
The gametogenic cycle of Ostrea edulis and Crassostrea gigas was studied in the outflow water of fish ponds in Eilat, Israel. Despite relatively high water temperatures (14–28°C) and high salinity (41 ± 2 ppt), both species developed gonads. O. edulis spawned from March to May, when water temperature ranged from 18 to 22°C, with a dormant period during the summer months. C. gigas spawned between May and August, when water temperature ranged between 20 and 26°C, with a dormant period between August and April. Spat never developed in the fish pond system.  相似文献   

3.
This paper provides information on the early life stages of the Moroccan Atlantic sardine, Sardina pilchardus, and two species of Sardinella: Sardinella aurita and S. maderensis, between Cape Blanc (21°N) and Cape Boujdor (26°N), dealing with the spawning grounds, the nursery areas and the optimal spawning temperature and salinity range.

The spawning areas for Sardina are located North of Dakhla (24°30′–25°30′N) and near Cintra Bay (23°N). The larval development area is described together with seasonal and annual characteristics. The nurseries of Sardina are near Dakhla and to the south between 21 and 22°N but precise locations vary with season. The maximum occurrence of eggs was during winter, and was at temperatures from 16 to 18 °C in winter and between 18 and 18.5 °C in summer.

The main spawning area of Sardinella species is between Cape Blanc and Cintra Bay (21–23°N) with a maximum occurrence of eggs and larvae in July. For Sardinella off the southern region of Morocco, the optimal temperature interval for spawning is between 18 and 21.14 °C. No conclusions can be drawn on the relationship between spawning and water salinity.

The area north of Cintra Bay has a broad, but shallow continental shelf. This topography leads to decreasing dispersion effects and the zone constitutes a favorable area for larval retention and development.  相似文献   


4.
Abstract. Previous studies have led to the development of a laboratory model for a disease termed 'winter saprolegniosis', locally referred to as 'winter kill', occurring in channel catfish, Ictalurus punctatus Rafinesque, raised in commercial ponds in the southeastern United States. In the laboratory, the onset of disease was routinely brought about by a combination of two related factors: (1) a rapid drop in water temperature which induces immunosuppression in catfish; and (2) maintenance of low water temperatures (∼10°C), which favour the proliferation of an ubiquitous fungus of the genus Saprolegnia to produce high levels of fungal zoospores (≥5 spores ml−1). In this study, two commercial catfish ponds were monitored for over one year to determine if the above factors occurred in the field and could be correlated with outbreaks of winter saprolegniosis. It was noted that passages of severe cold weather fronts were able to drop pond water temperatures ≥10°C within 24h and that such decreases in water temperature were associated with immunosuppression of the catfish in the ponds. Furthermore, when Saprolegnia sp. zoospore levels were ≥5 spores ml-1, the immunocompromised catfish exhibited overt signs of winter saprolegniosis. If one of the factors implicated in the induction of disease was missing, fish in the ponds remained healthy. In addition, the onset of disease in the ponds appeared independent of pH and oxygen, total ammonia nitrogen and un-ionized ammonia levels. Collectively, these field results confirm the laboratory-based hypothesis concerning the aetiology of winter saprolegniosis in channel catfish.  相似文献   

5.
Cage‐pond integration system is a new model for enhancing productivity of pond aquaculture system. A field trial was conducted using African catfish (Clarias gariepinus) and Nile tilapia (Oreochromis niloticus) in cages and carps in earthen ponds. There were four treatments replicated five times: (1) carps in ponds without cage, (2) tilapia at 30 fish m?3 in cage and carps in open pond, (3) catfish at 100 fish m?3 in cage and carps in open pond, (4) tilapia and catfish at 30 and 100 fish m?3, respectively, in separate cages and carps in open pond. The carps were stocked at 1 fish m?2. The cage occupied about 3% of the pond area. The caged tilapia and catfish were fed and the control ponds were fertilized. Results showed that the combined extrapolated net yield was significantly higher (P < 0.05) in the catfish, tilapia and carps integration system (9.4 ± 1.6 t ha?1 year?1) than in the carp polyculture (3.3 ± 0.7 t ha?1 year?1). The net return from the tilapia and carps (6860 US$ ha?1 year?1) and catfish, tilapia and carps integration systems (6668 US$ ha?1 year?1) was significantly higher than in the carp polyculture (1709 US$ ha?1 year?1) (P < 0.05). This experiment demonstrated that the cage‐pond integration of African catfish and Nile tilapia with carps is the best technology to increase production; whereas integration of tilapia and carp for profitability.  相似文献   

6.
This study documents early out-of-season induced spawning of channel catfish Ictalurus punctatus. During the early spring (February–April) of 1999, 2000 and 2001, ponds containing (1) male and female channel catfish (mixed-sex ponds) or (2) male channel and blue catfish I. furcatus only, or female channel catfish only (single-sex ponds) were heated to 24–30°C to encourage gonadal maturation and spawning. Unheated ponds were stocked with males and females and were monitored during the duration of heating. When natural spawning occurred in the heated ponds, the fish were captured by seining and unspawned females were injected with 100 μg kg−1 of synthetic leutenizing hormone-releasing hormone. Injected females were either paired with males or held in communal all-female groups, and monitored for ovulation. Eggs were collected and fertilized with sperm of channel catfish or blue catfish. Females paired with males were induced to spawn 44 days (mixed-sex ponds) and 50 days (single-sex ponds) before natural spawning occurred in unheated ponds. Spawning latency (the time between injection and ovulation) and the percentage of neurulated embryos from eggs fertilized using channel catfish sperm was not different between spawning before the natural season (P=0.68) and during the natural season in fish from mixed-sex ponds (P=0.57). Females held in all-female groups produced eggs 34 days before the onset of spawning in unheated ponds. Spawning latency was not different between spawns before and during the natural season (P=0.16), and the percentages of neurulated embryos from eggs fertilized with channel catfish sperm (P=0.76) or blue catfish sperm (P=0.77) before or during the natural season were not different. This study demonstrates the feasibility of conditioning of channel catfish females for early out-of-season induced spawning in the laboratory.  相似文献   

7.
Abstract— Laboratory studies with pond water samples revealed that 5 mg/L active chlorine was needed to provide enough chlorine residual to reduce biological activity. Treatment of channel catfish ponds with repeated, 0.1-mg/L doses of active chlorine from calcium hypochlorite at 6- to 8-d intervals, as sometimes done by catfish farmers, had little influence on water quality. Dissolved oxygen, total ammonia-nitrogen, and chlorophyll a concentrations and pH were similar between treated and control ponds. Concentrations of chemical oxygen demand and particulate organic matter were seldom different between treated and control ponds. Channel catfish survival and net production were not improved by chlorine treatment. Thus, chlorination of production ponds during the grow-out period is not a useful technique. Treatment of sediment samples from ponds with up to 1,200-mg active chlorinelkg soil did not reduce bacterial abundance, so chlorination of bottoms of empty ponds may not he an effective disinfection procedure. Chlorination of pond waters with 30-mg/L active chlorine caused complete kill of bacteria 24 h after treatment, although heterotrophic bacteria quickly re-populated the water. Thus, chlorination can be an effective way to disinfect ponds before stocking.  相似文献   

8.
An environmental assessment was made of Alabama channel catfish Ictalurus punctatus farming which is concentrated in the west‐central region of the state. There are about 10,000 ha of production ponds with 10.7% of the area for fry and fingerlings and 89.3% for food fish. Food fish production was about 40,800 tons in 1997. Watershed ponds filled by rainfall and runoff make up 76% of total pond area. Water levels in many of these ponds are maintained in dry weather with well water. The other ponds are embankment ponds supplied by well water. Harvest is primarily by seine‐through procedures and ponds are not drained frequently. The main points related to Alabama catfish farming and environment issues are as follows: 1) catfish farming in Alabama is conservative of water, and excluding storm overflow, about two pond volumes are intentionally discharged from each pond in 15 yr; 2) overflow from ponds following rains occurs mostly in winter and early spring when pond water quality is good and stream discharge volume is high; 3) total suspended solids concentrations in pond effluents were high, and the main sources of total suspended solids were erosion of embankments, pond bottoms, and discharge ditches; 4) concentrations of nitrogen and phosphorus in effluents were not high, but annual effluent loads of these two nutrients were greater than for typical row crops in Alabama; 5) ground water use by the industry is about 86,000 m3/d, but seepage from ponds returns water to aquifers; 6) there is little use of medicated feeds; 7) copper sulfate is used to control blue‐green algae and off‐flavor in ponds, but copper is rapidly lost from pond water; 8) although sodium chloride is applied to ponds to control nitrite toxicity, stream or ground water salinization has not resulted from this practice; 9) fertilizers are applied two or three times annually to fry and fingerling ponds and occasionally to grow‐out ponds; 10) hydrated lime is applied occasionally at 50 to 100 kg/ha but this does not cause high pH in pond waters or effluents; 11) accumulated sediment removed from pond bottoms is used to repair embankments and not discarded outside ponds; 12) sampling above and below catfish pond outfalls on eight streams revealed few differences in stream water quality; 13) electricity used for pumping water and mechanical aeration is only 0.90 kW h/kg of production; 14) each metric ton of fish meal used in feeds yields about 10 tons of dressed catfish. Reduction in effluent volume through water reuse and effluent treatment in settling basins or wetlands does not appear feasible on most farms. However, some management practices are recommended for reducing the volume and improving the quality of channel catfish pond effluents.  相似文献   

9.
A 36 year (1951–1986) record of water temperatures in Mississippi catfish ponds is synthesized from relationships with existing air temperature records. Multiple regression analysis is used to produce the following predictor equations for morning and afternoon pond temperatures: morning pond temperatures = 2.218 + 0.062(max air temp, day before) + 0.285(min air temp, same day) + 0.561 (afternoon pond temp, day before) (1) afternoon pond temperatures
= 2.071 - 0.068(min air temp, same day) + 0.651 (morning pond temp, same day) + 0.373(max air temp, same day) (2)
The derived pond temperature record is analyzed to produce annual average regimes; daily average, maximum, and minimum temperatures with standard deviations; and probabilities at 10 levels of Occurrence through the year and for each individual month. Applications for the aquaculture industry are presented and evaluated.  相似文献   

10.
Data collected from 45 commercial channel catfish, Ictalurus punctatus, ponds were used to develop empirical models predicting sediment oxygen demand (SOD). Seven acceptable models were combined with a Monte-Carlo sampling distribution to predict industry-wide sediment oxygen demand (SODi). The SODi values obtained from the best equation were used in simulations to assess the effect of diurnally varying water column dissolved oxygen (DO) concentrations on SOD and the effect of pond water depth on the contribution of SOD to overall pond respiration. Estimated SODi ranged from 62 to 962 mg m−2 h−1, with a mean of 478 mg m−2 h−1. There was a 95% probability of mean SODi being ≥700 mg m−2 h−1. The effects of diurnal variation in DO concentration in the water column on expression of SOD was modeled by combining maximum SODi, an empirical relationship between DO and SOD, and simulated pond DO concentrations. At DO concentrations >15 mg l−1, diel SOD in catfish ponds exceeded 20 g O2 m−2 day−1. But when average diel DO was <4 mg l−1 and the range of DO concentration was 6–8 mg l−1, SOD decreased to 13 g O2 m−2 day−1 because DO availability limited the full expression of potential SOD. Respiration totals for sediment (average SODi), plankton, and fish respiration were calculated for pond water depths ranging from 0.25 to 4 m. Although whole-pond respiration increases as pond depth increases, the proportion of total respiration represented by sediment decreased from 48 to 10% by increasing water depth over this range. The results of these studies show that SOD is a major component of total pond respiration and that certain management practices can affect the impact of SOD on pond oxygen budgets. Mixing ponds during daylight hours, either mechanically or by orienting ponds for maximum wind fetch, will increase oxygen supply to sediments, thereby allowing maximum expression of SOD and maximum mineralization of sediment organic matter. Given a mixed condition caused by wind or other artificial means, the construction of deeper ponds increases the total mass of DO available for all respiration, causing nighttime DO concentrations to decline at a slower rate, reducing the need for supplemental aeration. Because a pond’s water volume decreases over time from sediment accumulation, annual aeration costs will increase with pond age. Constructing ponds with greater initial depth will therefore reduce long-term cost of aeration, allow more flexible management of pond water budget, and reduce the long-term expense associated with pond reconstruction.  相似文献   

11.
Threadfin shad Dorosoma petenense are often stocked into commercial catfish ponds for biological control of algae. It is thought that the fish will alter the phytoplankton community, improve water quality, and enhance channel catfish production. Co-stocking of shad and catfish is a common practice, although there is limited information regarding the effects of threadfin shad on pond dynamics and catfish production. To evaluate the influence of shad in catfish ponds, this study was conducted in ten 0.04-ha experimental earthen ponds near Auburn, Alabama. All ponds were stocked in April with 600 fingerling channel catfish Ictal-urus punctatus (13,200/ha) with a mean length of 10.4 cm (4.1 in). Additionally, five of these ponds were randomly chosen and stocked with 70 adult threadfin shad (1,750/ha) weighing a total of 3.3 kg (16.5 kg/ha). At harvest in November, an average of 1,284 threadfin shad (32,100/ha), weighing a total of 55 kg (1,375 kg/ha) were collected from each shad pond. Water quality was improved with the addition of threadfin shad to channel catfish ponds. Mean total ammonia-nitrogen was significantly lower and less variable in the shad treatment. Observed mean nitrite concentrations, though not significant, were lower in the shad treatment. The phytoplankton community of the shad treatment had significantly higher density, more taxa, and smaller organisms. Pond water in the shad treatment had higher projected early morning dissolved oxygen levels requiring less aeration. Channel catfish had significantly higher survival in the shad treatment, furthermore, though not statistically significant, observed mean fish production was higher and feed conversion ratio was lower than in the no-shad treatment.  相似文献   

12.
Water temperature in eight ponds and air temperatures were monitored at 2-h intervals during the 2010 growing season at an inland, low-salinity shrimp farm in Alabama. There was a high correlation (P < 0.01) between mean daily air and water temperatures; pond water usually averaged 3° to 4°C warmer than air. Monthly mean water temperatures among eight ponds differed by 3.40°C in May and by 2.83°C in September, but there was less than 1°C difference among ponds in June, July, and August. Differences in temperature among ponds were not related to pond water surface:volume ratio, but in July and September there was a negative correlation (P < 0.05) with increasing aeration rate. Negative correlations (P < 0.05) between average water temperature over the entire culture period and survival and production of Pacific white shrimp, Litopeneaus vannamei, possibly resulted from variation in crop duration and were not causal. Nevertheless, differences in water temperature among ponds in May and September were great enough to have possibly caused differential shrimp survival and production among ponds.  相似文献   

13.
Pingguo He   《Fisheries Research》2003,60(2-3):507-514
Swimming behaviour of winter flounder (Pleuronectes americanus) was recorded near baited hooks on natural fishing grounds using an underwater video camera. Winter flounder were observed to stay on or very close to the seabed, never rising to more than 0.6 m off bottom during 1 month of observation. Winter flounder were recorded to take bait actively at temperatures as low as −1.2 °C. Movement of winter flounder was characterised by a period of swimming off seabed followed by a period of resting on the seabed. The proportion of time swimming off seabed as opposed to resting on the seabed was positively related to water temperature. Flounder spent an average of 32% of time in swimming when at −1.2 °C compared with 67% when at 4.4 °C. Voluntary swimming speed of the flounder during the period of swimming was lower at lower temperatures. An average swimming speed of 0.52 body lengths per second (L s−1) at −1.2 °C was recorded compared with 0.95 L s−1 at 4.4 °C. Overall rate of movement was reduced by three-fold when water temperature fell from 4.4 to −1.2 °C. The reduced rate of movement at lower temperatures is discussed in relation to potential fishing area of fixed fishing gears such as gillnets.  相似文献   

14.
The jack mackerel population has a widespread oceanic spawning habitat off central Chile, extending more than one thousand nautical miles offshore. In this paper, the spatial structure of jack mackerel eggs density is analyzed on the basis of four surveys carried out in oceanic waters (32°S–39°S, 75°W–92°W), from 1998 to 2001. In each survey, a grid of plankton stations was sampled through vertical hauls with WP2 plankton nets by using several purse-seine fishing ships sampling simultaneously along the E–W transects. With the aim of finding the bulk of the egg distribution within the surveyed area, an exploratory analysis between jack mackerel egg densities, latitude, longitude, and sea surface temperature (SST) was carried out. The spatial structure of the egg distribution was studied using geostatistical techniques. The bulk of the jack mackerel spawning tends to occur offshore between 80°W and 92°W, is maximal at 35°S and associated to SST warmer than 15–16 °C. All of the variograms showed clear spatial autocorrelations without anisotropy, with the range fluctuating between 125 and 252 nautical miles. The range of variograms suggests that the spawning of jack mackerel is a large scale process, probably reflected in the adult behavior of the spawning by favoring a high dispersion of eggs and/or associated with sea surface temperature characterizing the subtropical frontal zone (16–18 °C) off central Chile.  相似文献   

15.
ABSTRACT:   An experiment in which water was circulated between shrimp aquaculture ponds stocked with 10 000 or 20 000 PL-15 stage Penaeus monodon , and mangrove enclosures each planted with 476 Rhizophora mucronata per enclosure, was carried out at the Samut Songkhram Coastal Aquatic Research Station, Faculty of Fisheries, Kasetsart University, Thailand. Shrimp survival rate was significantly higher ( P  < 0.001, Fisher's exact test) in ponds where 10 000 larvae was stocked and water was exchanged with the mangrove enclosure, compared with the control pond with no water exchange, over the 136 day experimental period. Phosphorus transport to the mangrove enclosure was estimated to be 0.41 kgP and 0.18 kgP over the experimental period and change in phosphorus content in mud was reduced there compared with the control pond. A load reduction effect to the environment was confirmed in this aquaculture system with mangrove enclosure compared with the phosphorus budget in the control pond, and 6.2 or 8.9 ha of mangrove area was estimated to be required by 1 ha shrimp ponds to fully process the phosphorus.  相似文献   

16.
To mitigate the serious water pollution caused by the rapid expansion of the aquaculture industry in recent years, the development of improved aquaculture systems with more efficient water usage and less environmental impact has become essential. In this study, a land-based recirculating aquaculture system (RAS) was established that consisted of purification units (i.e., a primary biological pond, two parallel horizontal subsurface flow constructed wetlands [CWs], and a long ecological ditch) and 4-5 series-connected recirculating ponds. This system was mainly designed to stock channel catfish (Ictalurus punctatus), fifteen spine stickleback (Spinibarbus sinensis) and yellow catfish (Pelteobagrus fulvidraco), and the culture efficacy was evaluated based on a 2-year field experiment covering two growing seasons. According to the results, the primary biological pond played a role in sedimentation or nutrient retention, although this was not as evident when the CWs were functioning. The water flowing through the wetland system at a hydraulic loading rate (HLR) of 600 mm/day displayed lower values for the temperature, pH, dissolved oxygen (DO), suspended solids, organic matter and nutrients, whereas the electrical conductivity (EC) was higher, suggesting the accumulation of dissolved solids in the system. Due to the recirculation treatment, the trophic status of the recirculating ponds increased gradually along the direction of the flow and was notably lower in comparison to the control. As a result, the fish production responded to the variation of the water quality, which was reflected in the measurements of culture efficacy (final weight, survival rate, SGR and yield). The three main rearing species showed a decreasing trend along the direction of the flow, which was higher compared to the control, whereas an opposite trend was observed for filter-feeding fish. A Pearson correlation analysis revealed that the main culture species were inclined to live in meso- or oligotrophic conditions, and the silver carp adapted to more eutrophic conditions. Because RAS can provide better environmental conditions year-round, the present culture method could be more suitable for species that are sensitive to water quality in typical subtropical areas.  相似文献   

17.
ABSTRACT

Fingerling channel catfish Ictalurus punctatus were exposed to Ichthyophthirius multifiliis-infested fish until immature trophonts developed. The fish were transferred to individual static fiberglass tanks filled with 600 L of pond water (total alkalinity and total hardness was 220 mg/L and 101 mg/L, respectively) and were treated with 0, 1.1, 2.2, 3.3, or 4.4 mg/L copper sulfate (CuSO4 · 5H2O) every other day for four treatments to evaluate its effectiveness to control mortality associated with ichthyophthiriasis. Water temperature was maintained at 18 ± 1°C. Fish were observed for ten days post-treatment and mortalities were recorded. Results indicate that half of the recommended dose (1.1 mg/L CuSO4) is needed to effectively control an occurrence of ichthyophthiriasis under the conditions of this study. However, fish culturists should be aware that effective CuSO4 treatment of ichthyophthiriasis on channel catfish raised in ponds may be influenced by water chemistry characteristics and suspended materials such as pond sediments.  相似文献   

18.
Temperature is recognized to be the most important environmental factor affecting growth in fish. Barramundi are cultured over a wide range of temperatures some of which approach the upper thermal tolerance for this species. A growth trial was conducted on juvenile barramundi to examine the effects of high temperatures ranging from the minimum optimal temperature (27 °C) for growth efficiency to the extreme upper thermal limits (39 °C) for feed intake, growth and growth efficiency. Juveniles (4.87 ± 0.32 g) were held at four different temperatures 27, 33, 36 and 39 °C and fed twice daily to satiation (503.5 g kg− 1 crude protein, 182.5 g kg− 1 lipid, 150.1 g kg− 1 ash, 20.52 GE MJ kg− 1). Feed intake (g·day− 1) and SGR (%·day− 1) increased with increasing temperature up to 36 °C. At 39 °C feed intake, growth, feed efficiency ratio, protein efficiency ratio and productive energy value were significantly lower than at the other temperatures. This demonstrates that growth was optimized at temperatures from 27 to 36 °C and that barramundi have a much wider range for maximum growth efficiency than previously thought.  相似文献   

19.
Continuous dissolved oxygen (DO) measurements were analyzed to evaluate the rates of pond metabolic processes related to productivity and respiration in three commercial catfish ponds in northwest Mississippi. Multiple regression models were constructed to assess the relative importance of various forcing functions on indices of net primary productivity (NPP) and whole pond respiration (WPR), duration of automated aeration, and DO concentration below various threshold values. Water temperature, solar radiation, wind run, cumulative feed, and lagged values of these parameters were considered as forcing functions. Generally, NPP and WPR were most strongly affected by water temperature and only weakly related to solar radiation. The duration of nightly aeration was also strongly related to water temperature, although 10-d cumulative feed was an important predictor in one pond. The best predictors of duration of DO below certain threshold values were NPP, WPR and wind run, the importance of which varied depending upon the pond and the threshold value considered. Change in feeding rate from one day to the next was inversely related to feeding rate on the previous day. The results of this analysis suggest that NPP and WPR rates, and the duration of required nightly aeration in commercial catfish ponds are controlled by factors not amenable to practical management control.  相似文献   

20.
In order to establish a large-scale hatchery technique for the sea squirt Halocynthia ritteri , the influences of water temperature on spawning induction, larval development and survival of H. ritteri were studied under laboratory conditions. The larvae of H. ritteri exhibited high sensitivity to changes in temperature. As temperature increased from 10 to 21 °C, the duration of larval stage was inversely related to temperature and the time to reach attached larvae stage decreased from 42.0 to 59.4 h. The biological minimum temperature for the early development of H. ritteri was estimated to be 0.22 °C. In relation to temperature, quadratic equations showed significant fits to the data of spawning rate, fecundity, fertilization, larval survival and attachment. Optimal temperatures for spawning rate, fecundity, fertilization rate, larval survival rate and attachment rate were estimated to be 14.9, 14.7, 13.2, 14.1 and 14.7 °C respectively. It is concluded that the range of 13–15 °C is optimal for spawning and larval rearing of sea squirts.  相似文献   

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