Use Of Clove Oil Research Articles

Anesthesia of wild female Persian sturgeon,Acipenser persicus(Borodin, 1897) breeders during controlled propagation: effects on hematological parameters, stress response and reproductive performance

This study examined the effects of anesthesia on the hematological and biochemical parameters as well as the reproductive performance of wild female Persian sturgeon, Acipenser persicus, during controlled spawning. Fourteen mature females were divided into two groups: ‘anesthetized’ and ‘non-anesthetized’. All activities including transportation, catheterizing and handling were performed with both groups: (i) under anesthesia (150 ppm clove oil), and (ii) without anesthesia. After 10 days storage and handling, blood samples were taken from all fish after anesthesia. No significant differences were found in the reproductive performance of either group. However, differences were found in the hematological parameters, with values being significantly higher in the non-anesthetized group, including neutrophils (34.36 ± 6.33% vs 23.63 ± 5.22%), monocytes (2.84 ± 1.70% vs 1.27 ± 0.64%), mean corpuscular volume (321.3 ± 39.40 pg vs 228.0 ± 24.46 pg) and mean corpuscular hemoglobin (106.9 ± 15.70 fl vs 76.50 ± 7.50 fl). Significantly lower values were found in the non-anesthetized group for lymphocytes (60.68 ± 7.25% vs 73.54 ± 4.80%), Hb (4.62 ± 0.74 mg dl−1 vs 6.28 ± 1.21 mg dl−1), Hct (13.86 ± 1.76% vs 18.84 ± 3.85%), red blood cell (0.43 ± 0.05 cell mm−3 vs 0.85 ± 0.13 × 106 cell mm−3) and white blood cell (22 403 ± 2240 cell mm−3 vs 35 318 ± 3084 cell mm−3). The non-anesthetized fish had significantly higher cortisol levels compared to the anesthetized group (62.33 ± 8.85 ng ml−1 vs 46.12 ± 8.07 ng ml−1). There was no difference in plasma glucose levels between groups. It is concluded that the use of clove oil as an anesthetic is suitable for handling of wild female Persian sturgeon in controlled propagation programmes. However, further research is needed to determine a standardized protocol for the safe application of anesthesia for use in sturgeons in general.

The effects of four anaesthetics on haematological and blood biochemical profiles in vimba bream, Vimba vimba

The aim of this study was to compare the effect of four anaesthetics on the haematological and blood biochemical profiles of vimba bream (Vimba vimba). The haematological and blood biochemical profiles of vimba bream were evaluated 10 min and 24 h after anaesthesia with MS 222 (100 mg/l), clove oil (33 mg/l), 2-phenoxyethanol (0.4 ml/l), Propiscin (1.0 ml/l) and compared to non-anaesthetised controls. The 10 min exposure to any of the anaesthetics did not show any effects on haematological profiles. The exposure to 2-phenoxyethanol and Propiscin significantly (P < 0.01) influenced levels of glucose and ammonia, and the activity of aspartate aminotransferase compared with the control group. The level of triacylglycerols was significantly (P < 0.01) increased and the activity of lactate dehydrogenase was significantly (P < 0.01) decreased by exposure to MS 222. The use of clove oil showed no effects on the haematological and blood biochemical profiles and is recommended as a suitable anaesthetic for vimba bream. Other anaesthetics tested affected blood biochemical profiles to some extent.  

Use of Clove Oil and Eugenol to Anesthetize Fingerling Shabut Barbus grypus

AbstractIn this study, the efficacy of four doses of clove oil and eugenol were compared to sedate fingerling Shabut Barbus grypus to various stages of sedation and recovery. The results from the present study indicated that effective concentrations were at 50 μL/L for eugenol (induction time: 58 ± 8 s; recovery time: 199 ± 15 s [mean ± SD]) and clove oil (induction time: 76 ± 6 s; recovery time: 161 ± 34 s). The induction times decreased significantly with the increasing concentrations of clove oil and eugenol, while recovery times increased with increasing concentrations of anesthetic (P < 0.05). Exposure of fish to 75 or 100 μL/L clove oil or to 50, 75, or 100 μL/L eugenol resulted in mean induction times ≤ 1 min. Fish did not become fully sedated within 3 min when treated with 25 μL/L clove oil. Other concentrations of both anesthetics, fish reached to full induction at ≤ 3 min and recovered from anesthesia ≤ 5 min. Our results showed the clove oil and eugenol are effective anesthetics for fingerling Shabut when used at concentrations of 50–100 μL/L.

Effect of anaesthesia with clove oil in fish (review)

Clove oil is an effective, local and natural anaesthetic. Many hatcheries and research studies use clove oil to immobilize fish for handling, sorting, tagging, artificial reproduction procedures and surgery and to suppress sensory systems during invasive procedures. Clove oil may be more appropriate for use in commercial aquaculture situations. Improper clove oil use can decrease fish viability, distort physiological data or result in mortalities. Because animals may be anaesthetized by unskilled labourers and released in natural water bodies, training in the proper use of clove oil may decrease variability in recovery and experimental results and increase fish survival. Here, we briefly describe many aspects of clove oil, including the legal uses of it, anaesthesia mechanism and what is currently known about the preparation and behavioural and pathologic effects of the anaesthetic. We outline methods and precautions for administration and changes in fish behaviour during progressively deeper anaesthesia and discuss the physiological effects of clove oil, its potential for compromising fish health and effectiveness of water quality parameters.

고등어(Scomber japonicus) 치어의 마취제로서 Clove oil, MS-222 및 2-Phenoxyethanol의 평가

The efficiency of clove oil, MS-222, and 2-phenoxyethanol was evaluated as anesthetics in juvenile Scomber japonicus. Stage A5 of anesthesia was assumed to be sufficient for conducting routine aquaculture procedures in less than 3 min, with recovery (stage R5) in less than 5 min. The lowest effective doses of the three anesthetics were 50 mg <TEX>$L^{-1}$</TEX> clove oil (anesthetic time of 71.3 s and recovery time of 167.0 s), 100 mg <TEX>$L^{-1}$</TEX> MS-222 (anesthetic time of 70.7 s and recovery time of 115.7 s), and 400 mg <TEX>$L^{-1}$</TEX> 2-phenoxyethanol (anesthetic time of 86.7 s and recovery time of 95.0 s). Anesthetic times decreased with increasing doses for all three anesthetic agents, and fish anesthetized with clove oil exhibited the longest recovery times. After 30 min, the highest plasma cortisol and lactate levels were detected with the use of clove oil, whereas the lowest values were observed with 2-phenoxyethanol. In addition, high glucose levels were maintained during recovery with clove oil, but the treatments did not significantly differ. The most effective of the three anesthetic agents was 2-phenoxyethanol, although all were considered acceptable for use in cultures of juvenile Scomber japonicus.

Use of clove oil to anaesthetize larvae of Russian sturgeon (Acipenser gueldenstaedtii)

The efficacy of clove oil as an anaesthetic was evaluated in larvae of Russian sturgeon (Acipenser gueldenstaedtii) using four anaesthetic concentrations varying from 0.20 to 0.75 g L−1 Mean length, 13.7 ± 0.70 mm, 44 larvae placed individually to the anaesthetic bath, and induction (I-1 and I-2) and recovery times (R-1 and R-2) recorded at 18.0 ± 0.01°C. Larvae failed to respond to external stimuli ≥3 min (3.19 min) and recovered in ≥5 min (5.10 min) at 0.20 g L−1 and at the other three doses larvae reached to syncopal stage in <3 min and recovered from anaesthesia <10 min. As expected, the higher dose of clove oil resulted in significantly shorter anaesthesia induction and longer recovery times. While correlation coefficients between induction time and dose determined as negative; r = 0.87 and a positive correlation r = 0.86 has been found between doses and recovery times (P < 0.01). The study demonstrated that clove oil can be used as an effective anaesthetic in larvae of Russian sturgeon and higher dose of clove oil prolonged the recovery time.

Herbal Remedies for the Treatment of Periodontal Disease - A Patent Review

Periodontal diseases, if left unchecked, can lead to major health problems. There are a number of traditional herbal remedies for the treatment and management of diseases related to teeth, gum and oral hygiene. Use of clove oil is an age old remedy still practiced for periodontal problems. Our aim is to present an overall view of the current strategies adopted for the formulation and application of traditional herbal remedies. The article provides a review of the patents obtained on herbal remedies for the treatment of periodontal diseases. In addition, it also provides an overall view of potent herbal remedies widely used for periodontal diseases.

Effects of the fish anesthetic, clove oil (eugenol), on coral health and growth

Ecological research within coral reefs often requires the use of anesthetics to immobilize organisms. It is therefore important to consider the effect of these chemicals on the surrounding flora and fauna, particularly to the corals themselves. We quantified the effects of clove oil, a commonly used fish anesthetic, on the growth and occurrence of bleaching in three species of corals: Acropora striata, Pocillopora verrucosa, and Porites australiensis. We compared coral responses to five treatments: a gradient of four clove oil concentrations (0-28%) in seawater, and one concentration of clove oil (14%) in ethanol. Each week, we assessed the presence of bleaching, and then applied the treatment. We measured growth over the duration of the 6-week experiment using the buoyant weight technique. Growth and bleaching showed a dose response to clove oil exposure, and the use of ethanol as a solvent had an additional deleterious effect, as also suggested by observed changes in concentrations of eugenol following field application. Overall, growth was reduced by 37.6% at the highest concentration (28% clove oil in seawater) relative to the control (0% clove oil). The reduction in growth was nearly as great (35.3% of the control) at half the concentration of clove oil (14%) when dissolved in ethanol. These results suggest the repeated use of clove oil (even without a solvent) can deleteriously affect corals.

Evaluation of Clove Oil Concentrations for Use as an Anesthetic During Field Processing and Passive Integrated Transponder Implantation of Juvenile Steelhead

We examined the efficiency of sedating juvenile steelhead Oncorhynchus mykiss with 12.5, 25, or 50 mg/l clove oil concentration as it would relate to in situ sampling and marking. We compared handling effort and processing time among dosages for fish sedated with clove oil, implanted with a 23-mm passive integrated transponder (PIT) tag, weighed, measured, and fin clipped. In addition, we compared anesthesia induction, recovery, and initial and delayed mortality among dosages for fish sedated with clove oil. Fish reached each anesthesia induction stage faster as clove oil concentration increased. Handling effort was significantly more difficult for individuals anesthetized in the 12.5 mg/l clove oil concentration compared to 25 or 50 mg/l. Handling effort did not differ between fish sedated with 25 or 50 mg/l. Handling time was significantly longer for fish anesthetized with 12.5 or 25 mg/l clove oil concentrations compared to 50 mg/l. Handling time did not differ between fish anesthetized with 12.5 or 25 mg/l. Processed fish (i.e. PIT tagged, weighed, measured, fin clipped) recovered significantly quicker when anesthetized with 12.5 mg/l clove oil concentration followed by 25 and 50 mg/l. Time to each anesthesia recovery stage did not differ between processed fish and controls. We observed no initial post-tagging mortality. Though we observed delayed mortality, it was low and did not significantly differ among clove oil concentrations. Our results support the use of clove oil as a fish anesthetic, and 50 mg/l was an effective concentration when used for PIT tagging juvenile steelhead.

Testing clove oil as an anaesthetic for long-distance transport of live fish: the case of the Lake Victoria cichlid Haplochromis obliquidens

Summary Clove oil can be used as an anaesthetic in the handling of marine and freshwater fish. Few studies report on its use for periods up to 48 h, for example, under long-distance transport conditions. This study tested the effect of different clove oil concentrations for 1–48 h on recovery and survival of the cichlid Haplochromis obliquidens, an ornamental fish species endemic to Lake Victoria. Haplochromis obliquidens were anaesthetized for 1 h using 5–25 μl L−1 clove oil. There was no correlation between clove oil concentration and post-anaesthesia recovery time (P = 0.15). On average, fish recovered within 9.5 ± 2 min, and no fish died within 24 h after recovery. Results from exposure of fish to 18–20 μl L−1 clove oil for up to 48 h suggested a narrow margin of safety as this concentration range induced mortality. At 18 μl L−1 recovery times ranged from 3 to 43 min between 24 and 36 h exposure, while fish exposed longer than 36 h recovered within 1–10 min, or within 1–2 min after 44–48 h. At the end of a 48-h transport experiment total ammonia levels were higher in transport water containing anaesthetized fish than for non-anaesthetized fish (1.65 ± 0.19 and 0.54 ± 0.08 mg L−1 NH + NH3, respectively). The combined use of clove oil and the selective ammonium ion exchanger zeolite was considered feasible as ammonia levels could be reduced by up to 82% compared to control bags without zeolite.

Use of clove oil to anaesthetize freshwater amphipods

The use of clove oil as a potential anaesthetic for freshwater amphipods was examined at 20 °C. Individuals of Gammarus minus, a common species in southern Illinois, USA, spanning the entire body size range (4.3–14.3 mm), were used to test four anaesthetic concentrations varying from 1.48 × 10−4 ml ml−1 to 5.9 × 10−4 ml ml−1. Small-bodied individuals (mean size = 5.4 mm ± 0.27SE) were used to test additional concentrations, up to 14.7 × 10−4 ml ml−1, a 10-fold span, to identify potential lethal concentrations. At the lowest concentration, time to anaesthesia and recovery was constant at all body sizes. For the three next higher concentrations, time to anaesthesia decreased with increasing concentration while recovery time increased. Activity of amphipods was not affected by the ethanol carrier. In addition, activity did not differ between amphipods that had recovered from anaesthesia and unexposed amphipods. At clove oil concentrations of 8.84 × 10−4 ml ml−1 and 14.7 × 10−4 ml ml−1, mortality was 7 and 40%, respectively, indicating, that 5.9 × 10−4 ml ml−1 was a safe working concentration. No mortality was observed with Gammarus acherondytes, a federally endangered cave amphipod on which the protocol with 80 μl of stock was used in the field. The method enabled us to obtain information on the endangered amphipod which normally would have required the sacrifice of individuals. Thus, research can continue on species for which population numbers are low and for which basic information is needed to formulate meaningful recovery plans.

APLIKASI MINYAK CENGKEH SEBAGAI OBAT BIUS PADA KAKAP PUTIH (Lates calcarifer Bloch)

The objective of this study was to determine the safety and efficacy of clove oil as an anesthetic in sea bass (Lates calcarifer) and the potential application of clove oil as anesthetic to facilitate the sea bass fry transportation. Acute toxicity test indicated the 24-hr LC50 value of clove oil in sea bass fry as 30 ppm with slope function of 1.079 (1.05 to 1.107). In efficacy test, fish were exposed to 5, 10, 15, 20 and 25 ppm of clove oil for 15 minutes. At 5 ppm, clove oil caused only sedation effect (partial loss of reaction to external stimuli) while at 20 ppm, fish entered anesthesia stage (failure to respond to external stimuli) within about 3 minutes. Fish recovered from a 15-min period of exposure in 20 ppm clove oil within less than 10 minutes following removal from the anesthetic solution. There was neither mortality nor abnormal behavior of fish during 15-min exposure of clove oil as well as during 7 days post recovery from anesthesia. The potential application of clove oil as an aid in the transport of sea bass fry in plastic bag was also investigated. At 5 ppm, clove oil could reduce activities of the fish without loss of equilibrium (sedation stage) during the 4 hour simulated transport at 50 fish per 1,000 ml sea water (15 ppt). At 20 ppm, clove oil caused loss of equilibrium in fish resulting in the anesthesia stage throughout the 4 hour period. However, there was no improvement on survival rate and fish behavior with the use of clove oil during and after this 4 hour transport. Simulated transport at 50 fish per 500 ml sea water (15 ppt) for 8 hour did show better significant survival rate with additional of 5 and 20 ppm clove oil. In both short and long term transport study, clove oil did show the benefit by reducing the fish activities judging from the reduction of oxygen consumption, ammonia and carbon dioxide levels. Addition of appropriate concentration of clove oil in transport water ensured that the fish would stay calm by reducing fish activity and therefore, prevented any drastic changes of water qualities.

Effects of Clove Oil Anaesthesia on European Catfish (Silurus glanis L.)

The aim of the study was to investigate acute toxicity of clove oil for European catfish and, using values of haematological and biochemical profiles of blood and histological tissue examinations, to assess the effects of the fish exposure to that anaesthetic. Acute toxicity values of clove oil for European catfish found were 10minLC50 76.70 mg l-1; 10minLC0.1 49.60 mg l-1; 10minLC99.9 118.50 mg l-1; 96hLC50 18.40 mg l-1; 96hLC0.1 10.70 mg l-1; and 96hLC99.9 31.90 mg l-1. Individual phases of anaesthesia and recovery were determined. The 10-min exposure to clove oil at a concentration of 30 mg l-1 caused a significant (p &lt; 0.05) increase in the concentration of triacylglycerols (TRIG), alanin aminotransferase (ALT) and decreased (p &lt; 0.05) in mean corpuscular haemoglobin concentration (MCHC) immediately after anaesthesia. The leukocyte counts were significantly (p &lt; 0.05) decreased 24 hours after anaesthesia. A significant (p &lt; 0.05) decrease of percentage distribution lymphocytes was found immediately after anaesthesia. On the other hand, percentage and absolute count of myeloid cells were increased. Increased percentage count of eosinophils outlasted 24 hours after anaesthesia, absolute counts of these cells were consistents with control. Histological examination showed capillary ectasia of gill filaments immediately after clove oil anaesthesia. Twenty-four hours after anaesthesia, no ectasia was observed. No histopathological changes were demonstrated in other tissues following anaesthesia. Results of the examinations suggest that the use of clove oil at a concentration of 30 mg l-1 does not cause irreversible damage in European catfish.

The use of clove oil, metomidate, tricaine methanesulphonate and 2-phenoxyethanol for inducing anaesthesia and their effect on the cortisol stress response in black sea bass (Centropristis striata L.)

Juvenile and adult black sea bass (Centropristis striata L.) were exposed to various concentrations of four anaesthetics to determine practical dosages for handling as well as for procedures such as bleeding, ovarian biopsy or tag implantation. In experiment 1, juveniles exposed to either 2.0 mg L−1 metomidate, 15 mg L−1 clove oil, 70 mg L−1 tricaine methanesulphonate (TMS) or 200 mg L−1 2-phenoxyethanol (2-PE) reached stage II of anaesthesia in 3–5 min and could be handled for weighing and measuring. All fish had completed recovery to stage III within 6 min. In experiment 2, the established concentrations of each anaesthetic were tested on juveniles to determine their ability to prevent a reflex to a subcutaneous needle puncture. All of the fish exposed to clove oil (20 mg L−1) and 40% of the TMS-treated (70 mg L−1) fish reacted while none of the fish anaesthetized in metomidate (2.0 mg L−1) or 2-PE (200 mg L−1) responded to the needle puncture. In experiment 3, metomidate (5.0 mg L−1), clove oil (30 mg L−1) TMS (125 mg L−1) or 2-PE (300 mg L−1) were all effective for performing an ovarian biopsy or tag implantation on adults. In experiment 4, TMS (125 mg L−1) exacerbated the cortisol response to a short handling stressor during a 30 min exposure. Fish anaesthetized in 2-PE (300 mg L−1), metomidate (5.0 mg L−1) or clove oil (40 mg L−1) had increased cortisol levels associated with the handling stressor but there were no further increases during the remainder of the experimental period. The results demonstrate that these anaesthetics are effective for sedation and anaesthesia of black sea bass and that the best choice is dependant upon the procedures to be performed.

Effects of clove oil anaesthesia on common carp (Cyprinus carpio L.)

The aim of the study was to investigate acute toxicity of clove oil for common carp and, using values of haematological and biochemical profiles of blood and histological tissue examinations, to assess the effects of the fish exposure to that anaesthetic. Acute toxicity values of clove oil for carp were found 10 minLC50 74.3&amp;nbsp;mg/l; 10minLC0.1 51.6 mg/l; 10minLC99.9 110.1 mg/l; 96hLC50 18.10 mg/l; 96hLC0.1 15.45 mg/l; and 96hLC99.9 19.80&amp;nbsp;mg/l. The fish were divided into four groups for haematological and biochemical examinations of blood and histological examinations of tissues. The groups were Control I (before the anaesthetic administration), Experiment I (immediately after 10 min anaesthesia at the concentration of 30 mg/l), Experiment II (24 hrs after 10 min anaesthesia) and Control II (controls examined in parallel with Experiment II). A total of 40 carp were examined. Clove oil anaesthesia had not effect on the haematological profile. The 10-min exposure to clove oil at a concentration of 30 mg/l caused a significant (P &amp;lt; 0.01) increase in the concentration of glucose (GLU) and inorganic phosphate (PHOS) immediately after anaesthesia. Clove oil anaesthesia had not effect on other biochemical indices. Histological examination showed capillary ectasia of gill filaments immediately after clove oil anaesthesia. Twenty-four hours after anaesthesia, no ectasia was observed. No histopathological changes were demonstrated in other tissues following anaesthesia. Results of the examinations suggest that the use of clove oil at a concentration of 30 mg/l does not cause irreversible damage in carp.

Effects of clove oil on the stress response of matrinxã (Brycon cephalus) subjected to transport

Fish transport is one of the most stressful procedures in aquaculture facilities. The present work evaluated the stress response of matrinxã to transportation procedures, and the use of clove oil as an alternative to reduce the stress response to transport in matrinxã (Brycon cephalus). Clove oil solutions were tested in concentrations of 0, 1, 5 and 10 mg/L during matrinxã transportation in plastic bags, supplied with water and oxygen as the usual field procedures in Brazil. Clove oil reduced some of the physiological stress responses (plasma cortisol, glucose and ions) that we measured. The high energetic cost to matrinxã cope with the transport stress was clear by the decrease of liver glycogen after transport. Our results suggest that clove oil (5 mg/l) can mitigate the stress response in matrinxã subjected to transport.

Effects of Clove Oil Anaesthesia on Rainbow Trout (Oncorhynchus mykiss)

Veli‰ek J., Z. Svobodova, V. Piaakova: Effects of Clove Oil Anaesthesia on Rainbow Trout (Oncorhynchus mykiss). Acta Vet. Brno 2005, 74: 139-146. The aim of the study was to investigate acute toxicity of clove oil for rainbow trout and, using values of haematological and biochemical profiles of blood and histological tissue examinations, to assess the effects of the fish exposure to that anaesthetic. Acute toxicity values of clove oil for rainbow trout found were 10 min LC50 81.1 mg·l -1 ; 10 min LC0.1 63.9 mg·l -1 ; 10 min LC99.9 100.1 mg·l-1; 96 h LC50 14.1 mg·l-1; 96 h LC0.1 12.5 mg·l-1, and 96 h LC99.9 16.2 mg·l-1. Clove oil anaesthesia had no effect on the heamatological profile of blood. A significant increase in the concentration of glucose (GLU) and ammonia (NH 3 ), and a significant decrease in the aspartate aminotransferase (AST) activity following a 10 min anaesthesia were found. A significantly decreased AST activity was also found 24 h after anaesthesia. Clove oil anaesthesia had no effect on other biochemical indices. Histological examination of the fish following anaesthesia revealed sporadic ectasia in gill lamellae 24 h after anaesthesia in 20% of fish. No histopathological changes were demonstrated in other tissues (liver, spleen, cranial and caudal kidneys). Results of the examinations suggest that the use of clove oil at a concentration of 30 mg·l -1 does

Temperature effects on anaesthesia with clove oil in six temperate‐zone fishes

The potential use of clove oil (eugenol) as an anaesthetic for Atlantic salmon Salmo salar, brown trout Salmo trutta, rainbow trout Oncorhynchus mykiss, whitefish Coregonus lavaretus, perch Perca fluviatilis and roach Rutilus rutilus was examined at 5, 10, 15 and 20° C using three anaesthetic concentrations (varying from 20 to 200 mg l−1) at each temperature. Substantial species differences in sensitivity to clove oil were observed, even amongst congeners, and there may be some disadvantages (slow recovery and possibly mortality) with using clove oil for 0+ year whitefish and at low temperatures for perch and roach.

The use of clove oil as an anaesthetic for the longfinned eel,Anguilla reinhardtii(Steindachner)

To handle large river eels during procedures such as measuring and tagging for field and aquaculture studies, they must be anaesthetized. During our initial biological studies of Anguilla reinhardtii (Steindachner) it was found that the anaesthetic benzocaine was relatively expensive and elicited a variable response, even when used at relatively high concentrations. Human health risks are also a concern when using benzocaine, as some of the eels may later be sold for human consumption. Therefore, experiments were done to evaluate the use of clove oil (a safe, naturally occurring product) for anaesthesia of this species at a range of temperatures (17 and 25 degrees C) and salinities (0-32 g L(-1)). It was found that clove oil provided a suitable anaesthetic response through this wide range of temperatures and salinities. Response times were found to be relatively variable for both benzocaine and clove oil. This variability may be related to stress, environmental factors, or the condition of the fish. Clove oil is recommended for anaesthesia of anguillid eels because it is effective, relatively inexpensive, and poses little risk to human health.

The use of clove oil as an anaesthetic and method for sampling intertidal rockpool fishes

A suitable concentration of clove oil for anaesthetizing eight common Australian intertidal fishes was 40 mg l−1. Induction and recovery times at this concentration varied markedly interspecifically, although were &lt;3 and 5 min, respectively for all but Enneapterygius rufopileus. The number of species in clove oil samples was remarkably similar to bilge pumping samples in both small and large pools, although the number of individuals was significantly lower than bilge pumping in large pools. Number of species and individuals recorded by visual census differed from clove oil and bilge pumping methods in both large and small pools. Failure to detect all fish in pools by clove oil sampling and visual census was due to the secretive behaviour of many species and the tendency for such species as Bathygobius cocosensis not to emerge from under rocks during induction to anaesthesia. Complete draining of pools by bilge pumping, although time consuming, was a more accurate method of sampling rockpool fish assemblages than clove oil. However, clove oil is an effective stand‐alone sampling method because the number of fish and individuals are remarkably similar to samples obtained by bilge pumping. Clove oil is a favourable anaesthetic for temperate Australian intertidal fishes as mortality is extremely low, it is inexpensive and user‐safe, and induction and recovery times are short, although still sufficient to record biological information and identifications of fish whilst under anaesthesia.