Commercial‐scale Validation of Temperature‐step Rearing on Growth Physiology in Turbot,Scophthalmus maximus

The aim of this study was to investigate the possible benefit of “temperature‐steps” (T‐steps) rearing for juvenile turbot (initial weight 15.1 g) under realistic production scale and to determine whether initial growth advantage is maintained throughout the rearing period to market size. One group (called T‐step 22‐19‐16) of juvenile turbot was reared at three different temperatures, that is, 22 C (from 17 to 60 g) followed by 19 C (from 60 to 100 g) and 16 C (>100 g); another group (called T‐step 19‐16) at two temperatures, that is, 19 C (from 17 to 100 g) and lowered to 16 C (>100 g); and the third group (called C16) at one constant temperature, that is, 16 C. Relative growth was significantly higher in the two T‐step groups, with the T‐step 19‐16 showing the highest overall growth. Feed conversion efficiency was highest in the 19‐16 group. Only minor effects of the experimental rearing on blood physiology were found, with one notable exception of inverse relationship between plasma glucose and growth. Overall, these findings indicate that a short interval of rearing fish at high temperature during the early juvenile phase may have a long‐term effect on biomass increment in turbot. This is an important finding for the turbot industry.     

Intraspecific Differences in Physiological Efficiency of Juvenile Atlantic Halibut Hippoglossus hippoglossus L.

We compared growth efficiency, feeding consumption, metabolism, excretion, and energy allocation in populations of juvenile Atlantic halibut from Norway, Iceland, and Canada reared at low (8 C), medium (12 C, 15 C) and high (18 C) experimental temperatures. Our findings show that protein utilization and energy allocation in juvenile Atlantic halibut varies among different populations, as the Norwegian population displayed the highest protein efficiency ratio, protein production value, and energy conversion efficiency compared to the Canadian population, while the Icelandic population showed overall intermediate growth performance. The results do not conform to a simple thermal adaptation model but might represent an example of: 1) local adaptation of fish populations; or 2) countergradient variation where shorter growing season at higher latitudes is compensated with higher physiological efficiency. These findings have implications for halibut culture, particularly in selection work focusing on growth performance.     

Hemoglobin genotypes of turbot (Scophthalmus maximus): consequences for growth and variations in optimal temperature for growth

We studied the growth properties of three different hemoglobin genotypes of juvenile turbot (Scophthalmus maximus) reared at 10, 14, 18 and 22 °C. The genotype Hb-I(2/2) displayed the overall highest growth rate in the temperature range 14–22 °C, whereas no differences were found at sub-optimal temperature (10 °C). The differences in growth were largest at optimal temperatures where the Hb-I(2/2) genotype displayed 13% higher growth than the two other genotypes. Optimal temperature for growth (T _opt.G) varied between the genotypes with the genotype Hb-I(2/2) displaying the highest T _opt.G (23.0 °C) and Hb-I(1/1) the lowest (19.0 °C). The biological significance of this link between biochemical genetic variation and physiological properties might be influences on growth pattern, ultimate size and age at first maturity. This is the first reported quantitative trait locus (QTL) for this species.     

Effect of weaning time on the performance of Trachinotus ovatus (Linnaeus 1758) larvae

Effect of weaning time on the larval performance of golden pompano Trachinotus ovatus was studied in the experimental condition. The same weaning regime started on four different days of posthatch (DPH): 13 DPH (W13), 16 DPH (W16), 19 DPH (W19) and 22 DPH (W22), respectively. Growth, survival, RNA/DNA ratios and mid‐gut cell height of fish were assessed in each weaning regime over time. Growth and survival rates of fish larvae weaned in the W19 and W22 regimes were significantly higher than those in the W13 and W16 regimes. No significant differences were found either between W19 and W22, or between W13 and W16 treatments. Fish showed a decrease in the RNA/DNA ratio in W13, but a trend of increase in W16, W19 and W22. Weaning time significantly affected the mid‐gut cell height in larval golden pompano. On 24 DPH, the mid‐gut cell height of fish in the W13 and W16 treatments was significantly thinner than those in the W19 and W22 treatments. Based on fish growth, survival, RNA/DNA ratio and mid‐gut cell height, weaning can be started on 13 DPH in golden pompano larvae, but we recommend that the best weaning window be 16–22 DPH. These results are supported by histological and nutritional evidence and would guide the weaning process for golden pompano larvae, and offer a useful approach to explore the weaning protocol in larval fish rearing.     

The development of size variation in Dover sole,Solea solea and turbot,Scophthalmus maximus: genetic variability between different geographical and among year class farmed strains

Growth and variation in size of turbot and sole larvae originating from different genetic sources were compared at different stocking densities, including genetically based information that might lead to a better knowledge of heterogeneity in cultivated populations. There was no effect of density on growth rate in either species. However, between the two sole batches there was an earlier metamorphosis of faster growing fish from Norway. In sole groups after metamorphosis, variation was stable and therefore no development of size variation was observed. There was no density effect on size variation within turbot batches before, or after metamorphosis. Spreading rate and growth rate were positively correlated in sole larvae indicating that growth of the smaller fish was not equal to the larger ones, but size variation followed a different pattern in turbot. No evidence for either overall significant heterozygosity excess, or deficiency was evidenced in the farmed strains of either species . However, significant differences between farmed populations in terms of genetic variability (θ) were reported, which was rather attributed to within differentiation than between strains. One could safely argue that different strains of Dover sole originated from different genetic sources (factorial analysis). Moreover, when the analysis was extended to individual loci to assess whether specific loci had any consistently larger, or smaller effect on heterozygosity, locus specific significant trends were discerned in turbot. A positive Heterozygosity Fitness (growth rate) Correlation (HFC) suggests that heterozygotes reported enhanced growth rates compared with homozygous ones in flatfish larvae, thus special precautions should be taken into account whenever different genetic structure patterns emerge, because of various flatfish broodstock geographical origin and year class samples.     

Effects of starvation and recovery on the survival, growth and RNA/DNA ratio in loliginid squid paralarvae

The ability of Loligo opalescens paralarvae to resist and recover from starvation was examined by measuring their survival, growth rate and RNA/DNA ratios during starvation and refeeding. Paralarvae were fed Artemia sp. nauplii, zooplankton and mysid shrimp. Fourteen days after hatching they were separated into five feeding treatments: a control treatment (food was always available) and treatments starved for 2, 3, 4 and 5 days, and then refed. Each day, 5–7 paralarvae from each treatment were anesthetized to measure mantle length and wet weight (WW), and then RNA and DNA were extracted using an ethidium bromide fluorometric technique. Paralarvae did not survive 4 and 5 days of starvation, showing that at 15 days of age and at 16 °C the limit to recovery was 3 days of starvation. Paralarvae starved for 2 and 3 days showed compensatory growth that mitigated the effects of starvation, in that at the end of the experiment (10 days), they attained mean final body weights similar to the control treatment. Differences in the RNA/DNA ratios between control and starved paralarvae were detected within 2 days of food deprivation. For paralarvae starved 2 and 3 days, it took 1 day after refeeding to attain RNA/DNA ratios not significantly different from the control treatment. Additionally, RNA/DNA ratios were highest during the day (0800, 1200, 1600 h) and lowest at night (0000, 0400 h), suggesting daytime feeding activity. Growth rates ranged from − 14% to 21% WW day^− 1 and the resulting equation between RNA/DNA ratio and growth rate (GR) of paralarvae was GR = 1.74 RNA/DNA − 11.79 (R² = 0.70). After starvation, there was a reduction in growth variability in all starved treatments, while growth variability remained high in the control treatment. Findings from the present study indicate that nucleic acids are a valid indicator of nutritional condition and growth in squid paralarvae.     

Temperature influences on California rainbow trout physiological performance

Although thermal influences on the physiology of rainbow trout (Oncorhynchus mykiss) have been widely studied, there is little information about the responses of different genetic strains to temperatures. The effects of water temperature (10, 14, 19, 22, and 25 °C) on food consumption rate, growth rate, gross conversion efficiency, resting routine oxygen consumption rate, upper critical thermal tolerance and critical swimming velocity were investigated in juvenile rainbow trout of the Eagle Lake (O. m. aquilarum) subspecies and the Mt. Shasta strain. No strain-related differences in conversion efficiency, oxygen consumption rates, thermal tolerance or swimming performance were observed in 1995 (19, 22, and 25 °C) or 1996 (10, 14, and 19 °C), but Mt. Shasta strain trout grew faster at highest temperatures than did Eagle Lake trout. Food consumption rates, growth rates, conversion efficiency, and oxygen consumption rates declined at the extreme temperatures (10 and 25 °C) in both Eagle Lake and Mt. Shasta trout. Swimming performance was temperature-independent between 10 and 19 °C (overall mean: 5.43 body lengths s^–1).     

Effects of the Faroese long-line fishery, other oceanic fisheries and oceanic variations on age at maturity of Icelandic north-coast stocks of Atlantic salmon (Salmo salar)

Investigations were conducted on the effects of oceanic variations (as indicated by sea temperatures) and catches of the Faroese, Norwegian Sea and West Greenland salmon fisheries on the sea-age composition of Atlantic salmon (Salmo salar L.) from 22 Icelandic north-coast rivers. Catches of grilse in rivers were strongly correlated among the 22 rivers, as were the ratios of grilse caught to two-sea winter (2SW) salmon caught the next year. Four of the 22 rivers showed increasing ratios over time and three of these rivers, all in the northeast, had significantly higher mean ratios after the expansion of the Faroese fishery than before (P < 0.05). No evidence was found from ratios for the other 18 rivers to suggest that Faroese fishing was significantly depleting those stocks, even though 13 micro-tagged north-coast salmon had been recovered in the fishery in the 1988–1989 season. No evidence was found that Norwegian Sea or West Greenland fisheries affected stock composition. The mean April–May sea temperature prior to when the smolts enter the sea was significantly and positively related to ratios in eight of the 22 rivers. This result, along with frequent significant correlations in ratios among rivers, indicated that more rapid growth of smolts in their first summer may have increased grilse to 2SW salmon ratios on several rivers.     

温度胁迫及恢复过程中褐牙鲆幼鱼GH、IGF-I、RNA／DNA比值和糖原的变化

褐牙鲆（Paralichthysolivaceus）幼鱼分别在温度8．5℃（T8.5）、13．0℃（T13.0）、17．5℃（T17.5）、22．0℃（T22.0）、26．5℃（T26.5）下养殖10d后,调整至生长最快的温度22．0℃养殖30d,研究了生长激素（GH）、类胰岛素生长因子I（IGF-I）、RNA／DNA比值和糖原质量分数的变化。除在胁迫阶段T17.5处理血浆IGF-I质量浓度显著低于T22.0处理外,不同处理的血浆GH和IGF-I质量浓度在胁迫和恢复阶段均无显著差异。不同处理的肝脏RNA／DNA比值仅在20-40d阶段有显著差异,不同处理的肌肉RNA／DNA比值在所有时间均无显著差异。胁迫结束时T8.5、T13.0、T26．5处理的肝脏糖原质量分数显著低于T17.5,处理,试验结束时T22.0处理肝糖原质量分数略低于其余处理。胁迫结束时T25.5处理肌肉糖原质量分数最高,而在恢复的第一个10d时T13.0处理肌肉糖原质量分数最高。不同温度下养殖10d导致的生长减缓能够在恢复至22．0℃后的30d内获得完全补偿生长,但此试验中GH、IGF-I和RNA／DNA比值与生长率不存在明显的相关性。     

Comparative growth and mortality of cultured Lion's Paw scallops (Nodipecten subnodosus) from Gulf of California and Pacific populations and their reciprocal transplants

This study focused on the comparison of growth and mortality of Lion's Paw scallops Nodipecten subnodosus from Gulf of California and Pacific populations and their reciprocal transplants, cultured in suspended module and bottom culture in Baja California Sur, Mexico. Environmental parameters were monitored to determine site‐specific differences and were correlated with scallops' population‐specific responses. Significant differences in growth were found between sites, populations and grow‐out methods. Growth performance of scallops originating from the Pacific population was lower and uniform between Pacific and Gulf culture sites, whereas Gulf scallops cultured at the Pacific site grew better. Growth and survival was higher in suspended than bottom culture, mainly due to depth‐associated differences in food and oxygen supply. Increasing temperatures and decreasing food and oxygen during summer months resulted in depressed growth and elevated mortality. At the Pacific site, this was partially compensated by considerably higher food availability. Gulf scallops resisted high diurnal temperature changes at San Buto significantly better than Pacific scallops. They also survived generally better than the Pacific population, independent of site and grow‐out method, indicating physiological adaptations to high temperatures and low food availability in their habitat. Consequently, the Gulf population appears to be more feasible for aquaculture operations in coastal lagoons with stressful conditions.     

Experimental rearing of juvenile New Zealand turbot Colistium nudipinnis (Waite 1910): a potential new aquaculture species

Investigations into factors affecting the growth of the first hatchery-produced juvenile New Zealand turbot Colistium nudipinnis (Waite 1910) showed that this endemic flatfish can be reared in raceways and tanks. After initial high mortality (> 60%) in the post-weaning period (to 120 days post-hatch), the juveniles showed high survival over the grow-out period. Growth of the juveniles was better at lower (16–18 °C) than at higher (> 20 °C) water temperatures, and better in a deep tank than in shallow raceways. Under the experimental rearing conditions, growth (to mean weight of 0.2 kg in 20 months) was relatively slow and food conversion (FCRs > 1.4) relatively high, both factors being related to the feeding behaviour of this species. C. nudipinnis feeds directly from the bottom, and this behavioural characteristic influences aspects of fish farming practice, such as stocking density and feeding strategy, that are critical to its economic viability. There is potential to improve the growth by optimizing the rearing conditions, so that it may not be unrealistic to achieve the maximum growth reached in these trials commercially and produce marketable farmed turbot, of over 400 g weight, within 2 years.     

Salinity During Early Development Influences Growth and Survival of Florida Red Tilapia in Brackish and Seawater

Growth of juvenile Florida red tilapin (1.57 g average weight) spawned and sex-reversed (monosex male) at salinities of 4 ppt and 18 ppt was compared at rearing salinities of 18 ppt and 36 ppt in 200 L aquaria under controlled photoperiod (12 L:12 D) and temperature (28 C). Growth was significantly higher for progeny spawned at 18 ppt than those spawned at 4 ppt under both rearing salinities with no difference observed between 18 ppt and 36 ppt.
In another experiment, growth of juvenile progeny (0.98 g average weight) spawned and sex-reversed at salinities of 2 ppt and 18 ppt was compared in 24 m³ outdoor pools at 36 ppt. When water temperatures exceeded 27 C, growth and survival were not significantly different between these groups. However, when temperatures fell below 25 C, growth and survival were significantly higher among progeny spawned at 18 ppt.
The results showed that progeny spawned and reared through early ontqenetic development in brackishwater are better adapted for growth in brackish and seawater and suggested that these fish may have higher resistance to cold-stress in seawater than progeny spawned in freshwater.     

Growth and survival of young turbot (Scophthalmus maximus L.) produced with cryopreserved sperm

This study assessed the growth and survival over a year of two groups of 4‐month‐old turbot Scophthalmus maximus (L.) derived from artificial fertilization with fresh (FG) and cryopreserved sperm (CG). Growth in both groups, measured monthly in terms of length and weight, were compared. Survival was also recorded. No significant differences were found when we compared weight and length data in both groups. Growth rates were similar between FG and CG young turbot during 1 year. Likewise, the same survival rate (92.2%) was found in both groups. Our results show the good survival and growth of young turbot obtained from cryopreserved sperm, and confirm the cryopreservation technique as a useful tool for raising turbot for commercial purposes.     

温度对白斑狗鱼耗氧率、窒息点及主要生化指标的影响

在不同温度下,测定了平均体重为(597.2±96.3)g的白斑狗鱼(Esox lucius)的呼吸耗氧率、窒息点及主要生化指标。结果显示:在水温为3℃、8℃、13℃和18℃下,白斑狗鱼的耗氧率随着温度的升高而显著上升(P<0.05)。3℃时耗氧率最低;为(0.0047±0.000017)mg/g.h,18℃时耗氧率最高;为(0.029±0.0011)mg/g.h。当水温在13℃时,白斑狗鱼的昼夜平均耗氧率在(0.020±0.0031)mg/g.h,15:00耗氧率最低,11:00耗氧率出现最高值。Q10值的变化显示白斑狗鱼的耗氧率对温度具有敏感性,13～18℃时,Q10最小,此温度为白斑狗鱼的较适生长温度。在高温下(18℃),白斑狗鱼呼吸急促,呼吸频率达到(68.50±3.58)次/min;在低温下(3℃),白斑狗鱼呼吸缓慢,呼吸频率下降到(29.00±4.31)次/min。白斑狗鱼的窒息点随着水温的升高而增大,水温为13℃,其窒息点最高为1.68 mg/L,水温为3℃时,其窒息点最低为0.82 mg/L。随着水温的不断上升,白斑狗鱼的肝糖元含量、肝胰脏中的乳酸含量显著减少(P<0.05)。肝糖元含量由(67.70±6.66)mg/g降至(41.83±3.72)mg/g。乳酸含量由(0.36±0.0041)mmol/gprot降至(0.15±0.0034)mmol/gprot。肝胰脏中的碱性磷酸酶、酸性磷酸酶的酶活力随着水温的升高而小幅缓慢下降,分别由(21.51±0.69)U/gprot和(22.34±0.43)U/gprot降至(19.04±0.62)U/gprot和(18.10±0.41)U/gprot。     

A comparison of epidemiological patterns of salmon lice, Lepeophtheirus salmonis, infections on farmed Atlantic salmon, Salmo salar L., in Norway and Scotland

This paper examines two large national data sets collected over several years and contrasts the patterns of sea lice, Lepeophtheirus salmonis (Krøyer, 1837), infections, the use of treatments and the occurrence of chalimus peaks between Norwegian and Scottish farms. Infection levels in Scotland were significantly higher in general over the period under study. For the chalimus stage group in the first quarter of the year, Norwegian mean abundance stayed below 10 lice per m² while Scottish means reached 45 lice per m² of fish skin per m³ of water. Both countries had more chalimus in summer than at other times of year, but in the last 3 months of the year Scottish fish had, on average, two to four times as many chalimus as Norwegian fish. Peaks of chalimus abundance were more frequent in Scotland, particularly in winter, but the most prominent peaks occurred in summer in both countries. In Scotland a marked mid-year build-up of mobile pre-adult and adult stages was seen, and both countries showed a tendency for mobile counts on the second year fish to increase towards the end of the year. Scottish fish carried, on average, three times as many mobile lice per m² of skin as Norwegian fish in the last 3 months of the year. The difference in lice loads was reflected in the greater use of veterinary medicines on Scottish farms. The higher infection levels in Scotland may be due to shallower and more enclosed water bodies used for farming, smaller and shallower pens, differences in sea water temperatures or in access to appropriate medication. The results highlight the importance of ensuring that effective veterinary medicines are available in the UK for the control of infection.     

Effects of temperature on the growth of pollack (Pollachius pollachius) juveniles

Growth of juvenile pollack was assessed at five constant temperatures (9, 12, 15, 18 and 21 °C) in an 84-day trial. Duplicate groups of 75 fish (initial weight 143 ± 2 g) were held in O₂ saturated water (102–103% saturation) and fed to apparent satiation. Growth increased as temperature increased from 9 °C up to a plateau at 12–15 °C (NS differences between 12 and 15 °C) followed by a decrease from 18 °C. No growth occurred at 21 °C. For the overall period, specific growth rates were 0.52% and 0.53% day^− 1 at 12 and 15 °C compared to 0.40% day^− 1 at 18 °C. Feed intake was maximum at 15–18 °C (0.68–0.69% day^− 1) and it was significantly lower at 21 °C (0.45% day^− 1). Apparent feed conversion ratio was significantly higher at 18 °C than at 12–15 °C (1.8 compared to 1.2–1.4). There was no significant change in fish whole body composition related to temperature.At the end of the experiment, fish growth recovery following a transfer from 18 and 21 °C to 15 °C was assessed using a 50-day challenge test. Growth rate of the previous 21 °C group was the same as in the 15 °C group (NS differences) and in the previous 18 °C group it was significantly lower. The study showed that pollack have a high capacity to recover from a prolonged period of low or no growth induced by high temperatures.     

Culture of the mysid, Mysidopsis almyra (Bowman), (Crustacea: Mysidacea) in a static water system: effects of density and temperature on production, survival and growth

The effects of animal density and water temperature on the culture of the mysid, Mysidopsis almyra (Bowman), in a static water system were evaluated. An initial set of experiments tested the effects of mysid density on production. Densities of 25, 37.5, 50, 100 and 200 mysids L^–1 were placed in trays with 20 L of sea water. Temperatures were maintained at 26 ± 2 °C. A second set of experiments was conducted in the same system at three different temperatures (18 ± 1, 22 ± 1 and 26 ± 2 °C) using a mysid density of 50 mysids L^–1 (1000 mysids tray^–1). All experiments had a duration of 30 days. The mysids in all trials were cultured at 20 ± 2‰ salinity and fed Artemia nauplii enriched with marine fatty acids. There was a positive correlation between production and mysid densities up to populations of 100 mysids L^–1; maximum production was 273 ± 99 hatchlings day^–1. At a population density of 200 mysids L^–1, high mortality and low production were recorded 4 days after the start of the experiment. The experiments testing different temperatures showed that mysid production was higher at 22 ± 1 °C, although this result was not significant (P > 0.05). Growth rates and hatchling survival after 7 days were significantly higher (P < 0.05) at 26 ± 2 °C compared to survival and growth at 18 or 22 °C.     

Feeding larvae of winter flounder Pseudopleuronectes americanus (Walbaum) with live prey or microencapsulated diet: linear growth and protein, RNA and DNA content

A commercial microencapsulated diet was used as a total or partial replacement of live prey for feeding larvae of winter flounder Pseudopleuronectes americanus (Walbaum), a potential alternative finfish species for coldwater marine aquaculture. Growth performance (morphometric measurements and biochemical composition) and nutritional condition (RNA/DNA ratios) of larvae fed live prey (Brachionus plicatilis Müller), a microencapsulated diet or a mixed diet of live prey and microcapsules were compared. Newly hatched larvae were unable to digest microencapsulated diet; live prey at initial feeding was required for their survival and growth. Larvae offered a mixed diet showed slower growth than larvae fed exclusively with live prey. However, at the onset of stomach differentiation, RNA/DNA ratios (indicators of protein synthesis potential) of the larvae fed both diets became similar. We suggest that, at that stage (size 5.5–6.3 mm), enzymatic activity had developed enough to allow digestion of inert food. As the RNA/DNA ratio is a good indicator of nutritional condition, it appears to be an interesting tool for the assessment of diet adequacy in marine larval feeding technology.     

Lasting Temperature Effects on the Muscle Tissue,Body Growth,and Fillet Texture of Adult Turbots,Scophthalmus maximus L.

Three groups of turbot, Scophthalmus maximus L., were reared at three different temperatures (Ts) from hatching until 150 d posthatching: warm (21–22 C), ambient (17–18 C), and cold T (15–16 C). Later on, all of them were transferred at ambient T until the end of the experiment (1.8 yr of age, at commercial size: ≈1.5 kg and 40 cm) in order to study the long‐term T effect on the growth. At 1 yr of age, almost all the muscle and body parameters were greater in the warm than in the rest of the groups. At 1.8 yrs of age, the reverse situation was found, such that almost all the muscle and body parameters were higher in the cold than in the rest of the groups, thus showing a compensatory growth in the cold group. In relation to the texture parameters, most of them did not show significant differences among the groups. In relation to the sex influence, the size of muscle fibers was lower in the female than in the male fish, whereas the number and the muscle fiber density were generally higher in female than in male fish. The texture parameters did not show significant sex influence.     

Effects of oxygen supersaturation and temperature on juvenile greenlip, Haliotis laevigata Donovan, and blacklip, Haliotis rubra Leach, abalone

Growth and survival of juvenile greenlip (39.03 (SD 3.80) mm (n=524)) and blacklip (31.92 (SD 4.19) mm (n=531) abalone were investigated at high dissolved oxygen levels (95–120% saturation) between 17 and 19°C. Abalone were fed the same artificial diet and each species was contained in groups of approximately 30 individuals within triplicate tanks for each of six treatments and were exposed to flow through water adjusted to give experimental conditions for up to 75 days. Blacklip abalone held at 16.9°C and 97% oxygen saturation grew in shell length significantly faster than all other treatments of blacklip abalone held at 19°C, and significantly faster than blacklip abalone maintained at 111% oxygen saturation and 17.5°C. Both temperature and oxygen saturation significantly affected the survival of this species. Blacklip abalone held at 19°C had significantly lower survival for both 96% oxygen saturation and 120% oxygen saturation, compared with blacklip abalone maintained at either 110% oxygen saturation and 19°C, or for any 17°C treatment. No significant differences were noted for greenlip abalone within the range tested in terms of growth rate, food consumption rate or survival, indicating that greenlip abalone tolerated these conditions better than did blacklip abalone.