Board index Aquaria Topics Fish Health and Water Chemistry 2013 AVMA Euthanasia guidelines.

2013 AVMA Euthanasia guidelines.

Discussion about fish health and water chemistry.

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Post Fri Mar 01, 2013 12:55 pm
nelson23 Level 2 Member
Level 2 Member

Posts: 43
In case anyone is interested in 2013 the American Veterinary Medical Association (AVMA) updated the Guidelines
for the Euthanasia of Animals:


I have put the sections pertinent to fish and inverts below. The entire guide can be found online. Hope it is useful for you.

S6. FINFISH AND AQUATIC INVERTEBRATES

S6.1 GENERAL CONSIDERATIONS

Finfish and aquatic invertebrates play important roles as food, pets, research subjects, display animals, sources of recreation, and key components of healthy ecosystems. In each of these situations it may be necessary to cause the death of some animals. Considerable evidence is accumulating suggesting it is appropriate to consider the possibility of pain perception in these species. The aim is to accomplish death for these animals rapidly with the minimum amount of pain and distress practicable. Because the environment associated with finfish and aquatic invertebrates in each of their roles is different, and because knowledge about the evolutionary and societal status of poikilothermic animals (lower vertebrates and invertebrates) is limited, identifying and applying appropriate criteria for euthanasia can be difficult.

S6.1.1 Terms Applicable to Ending Life

Specific to finfish, the three main terms used to describe the ending of life are euthanasia, slaughter, and humane killing. There is often confusion regarding how these terms and their associated methods differ. The methods described in the Guidelines serve as guidance for veterinarians and others who may need to perform euthanasia. The Guidelines are not intended to specifically address slaughter or humane killing methods. Slaughter is used primarily to describe the humane killing of animals intended for human consumption for food or other uses (eg, agricultural harvest, commercial fishing). Humane killing is less specific and can be used to describe some recreational fishing practices and may also include activities such as finfish sampling, depopulation, eradication, and control to eliminate unwanted finfish (including diseased or nonnative finfish) from a water body. A fourth term, harvest, specifically refers to the act or process of gathering a crop, as in aquaculture and commercial fishing; however, harvest may also be used to describe finfish removed from a water body by anglers. Whether harvested finfish are slaughtered or humanely killed depends on the context of the activity. Neither slaughter nor humane killing is addressed by this document. Addressing euthanasia of invertebrates in some settings is not meant to discount the necessity for and suitability of slaughter and pest control techniques that do not meet the definition of euthanasia. Nor is the intent of this document to advocate the expansion of coverage of IACUC to invertebrates.

S6.1.2 Human and Animal Considerations

Because of the diversity of physiologic and anatomic characteristics seen among species of finfish and aquatic invertebrates, optimal methods for euthanasia will vary. Euthanasia choices for finfish and aquatic invertebrates must account for animal stress responses and human safety concerns associated with handling, as well as differences in metabolism, respiration, and tolerance to cerebral hypoxia. Virtually all methods require that personnel be carefully trained and monitored (although some carry more risks of human ineffectiveness than others), some require DEA registration and record keeping, extra-label use requires administration by or under the supervision of a veterinarian, and chemicals regulated by the EPA can only be legally used according to their label directions. Intra-coelomic injections carry an inherent risk of organ damage and response time may vary. Intravenous injections require careful handling of finfish, as well as trained and experienced personnel. Intramuscular injections with ketamine, α2 adrenergic receptor agonists, or Telazol can be administered via pole syringe or dart gun to larger finfish to facilitate handling and reduce handling stress for finfish, but rarely achieve surgical planes of anesthesia in teleosts. In all cases, veterinarians and others with expertise relevant to the species of interest should be consulted; professional judgment and relevant expertise should be taken into account when ultimately determining the best method to use. In addition, it is often more difficult to ascertain when a finfish or an aquatic invertebrate is dead as compared with birds and mammals. Some unique aspects of euthanasia for finfish have been described.

S6.1.3 Preparation and Environment

As a general principle the preparations for euthanasia of finfish should be very similar to the preparations for anesthesia of finfish. If possible, withholding food for 12 to 24 hours prior to euthanasia will reduce regurgitation, defecation, and nitrogenous waste production. The environment should be as quiet and nonstimulatory as possible given the circumstances. Light intensity should be reduced if possible, but with adequate lighting for personnel. This can also be achieved through use of a dark or opaque container and lid, or by use of less intense lighting, (eg, red light illumination, as red light does not penetrate water well).

Water quality should be similar to that of the environment from which the finfish originated, or optimized for that species and situation, for the duration of euthanasia. If of acceptable quality for finfish health, water in which they have been house or captured should be used, and supplemental aeration and temperature control may be necessary. Either the immersion euthanasia solution is prepared with water from the finfish housing system and the finfish are transferred into it or a concentrated form of the anesthetic agent as a solution (containing buffering agent if appropriate) is introduced directly into the container of finfish to minimize stressors. If euthanizing a large population of finfish, it is important to monitor the anesthetic bath water quality (temperature, dissolved O2, and organic loading, in particular). The euthanasia agent may need to be supplemented or replaced periodically. Euthanasia methods should be tested in one animal or a small group of animals prior to use in a large population for an unfamiliar species. If handling is required, appropriate equipment (nets, gloves) should be used to minimize stressors.

S6.1.4 Indicators of Death in Finfish and Aquatic Invertebrates

Because the thousands of species of finfish and aquatic invertebrates vary greatly in anatomic and physiologic characteristics, reliable indicators of death may not be available for some. However, there are some standard approaches that can be useful for many of the more commonly encountered species. Loss of movement, loss of reactivity to any stimulus, and initial flaccidity (prior to rigor mortis) may serve as indicators of death for finfish and some aquatic invertebrates. More useful indicators for many finfish include respiratory arrest (cessation of rhythmic opercular activity) for a minimum of 10 minutes and loss of eyeroll (vestibuloocular reflex, the movement of the eye when the finfish is rocked from side to side). The latter is no longer present in finfish that have been deeply anesthetized or euthanized. The heart can continue to contract even after brain death or removal from the bodies of finfish,558 so the presence of a heartbeat is not a reliable indicator of life, but sustained absence of heartbeat is a strong indicator of death. For more sessile, less active organisms, or those with specific anatomic or physiologic adaptations that prevent use of these indicators, it may be more difficult to assess loss of consciousness and death, and consultation with species experts is recommended.

S6.1.5 Disposition of Euthanized Animals

Any euthanized finfish or invertebrate should be promptly removed from its aquarium, pond, or other vessel and disposed of according to all pertinent federal, state, and local regulations, in a manner that will reduce the risk of disease spread, prevent pests and other nontarget species from gaining access to animal remains, and ensure human and environmental safety. Preventing environmental contamination by any life stage of finfish that could hatch and/or survive outside an acceptable, enclosed body of water is an important consideration in confirmation of death and disposal of the animal’s remains.

S6.1.6 Finfish and Aquatic Invertebrates Intended for Human Consumption

As previously indicated, the term slaughter is used primarily to refer to the killing of animals intended for human consumption (eg, agricultural harvest, commercial fisheries) and these Guidelines are not intended to address that activity. However, when euthanasia of animals intended for human consumption is desired, tissue residues from the use of drugs and other chemicals will make many methods unacceptable unless they have been approved by the FDA for this purpose and appropriate withdrawal periods are followed. Use of any unapproved chemicals for euthanasia prohibits entry of the finfish into the food chain, either by rendering, as fish meal, or as directly consumed product.549 With that said, currently there are no drugs approved for euthanasia of finfish or aquatic invertebrates. Carbon dioxide is a drug of low regulatory priority that avoids unacceptable residues, but it is not an FDA approved method for killing aquatic animals used for food. Physical methods that are acceptable with conditions include manually applied blunt force trauma to the head, decapitation, and pithing.

S6.2 FINFISH

Common methods used to euthanize finfish include noninhaled methods (i.e., immersion and injection) and physical methods. Because of general differences in anatomy and application seen between finfish and terrestrial animals (especially with regard to primary respiratory organs, and aqueous vs. air environment), techniques involving addition of drugs to the finfish’s environment (i.e., the water), for purposes of this document, are considered noninhaled methods.

Descriptions of methods used to euthanize finfish follow and include 1-step and 2-step procedures. Each method is further classified as acceptable, acceptable with conditions, or unacceptable considering characteristics of the methods and the environments in which euthanasia is conducted, including veterinary private practice (eg, companion and ornamental [display] finfish), ornamental (aquarium) finfish wholesale and retail facilities, research laboratories, and finfish kept outdoors and in fisheries. An acceptable method reliably meets the requirements of euthanasia. Methods that are acceptable with conditions reliably meet the requirements of euthanasia when specified conditions are met. An unacceptable method does not meet the requirements of euthanasia. Because finfishes’ anatomic and physiologic characteristics are quite different from those of mammals and birds, classification of techniques may vary from what has been recommended for other species.

S6.2.1 noninhaled Agents

Immersion (1 step)—Intentional overdose via immersion in anesthetic solutions is a common method of euthanasia for finfish. Finfish should be left in the anesthetic solution for a minimum of 10 minutes after cessation of opercular movement. Options include the following:

(1) Benzocaine or benzocaine hydrochloride, buffered. Solutions for immersion should be prepared in concentrations of 250 mg/L and should be buffered.

(2) Carbon dioxide. Immersion in CO2-saturated water causes narcosis and loss of consciousness after several minutes. Some species may exhibit hyperactivity prior to loss of consciousness. Purity and concentration of CO2 are important for effectiveness. Only CO2 from a source that allows for careful regulation of concentration, such as from cylinders, is acceptable. Care must be taken when using CO2 to prevent exposure to personnel (ie, euthanasia must be conducted in well-ventilated areas).

(3) Ethanol. Ethanol has been suggested as an acceptable alternative method for finfish. The depressive effects of ethanol on the CNS are well described, and exposure of zebrafish via immersion has become a model for behavioral and molecular responses to alcohol, at concentrations from 10 to 30 mL of 95% ethanol/L. At this dose, alcohol induces anesthesia, and prolonged immersion produces death via respiratory depression causing anoxia. This is not equivalent to immersing finfish directly into preservative concentrations of ethanol (70%), which is not acceptable as a euthanasia method.

(4) Eugenol, isoeugenol, and clove oil. Whenever possible, products with standardized, known concentrations of essential oils should be used so that accurate dosing is possible. Concentrations required for anesthesia will vary depending on species and other factors, but may be as low as 17 mg/L for some species. Greater concentrations will be required for euthanasia. Finish should be left in the anesthetic solution for a minimum of 10 minutes after cessation of opercular movement. These compounds are equivocal or known carcinogens according to the National Toxicology Program. Some studies in rodents indicate this group of anesthetics may cause paralysis in addition to having anesthetic effects, and analgesic properties are unknown. Because some clove oil products may contain or include either methyleugenol or isoeugenol, or both, FDA has expressed concern that the use of clove oil or its components in finfish may adversely affect human food safety and animal food safety. In addition, because clove oil and its components have not been evaluated for target animal safety, FDA is also concerned that the use of any of these compounds may adversely affect finish, including endangered aquatic species. Isoeugenol is a potential carcinogen so human safety in the application of that agent is of concern.

(5) Isoflurane, sevoflurane. These concentrated liquid anesthetics can be added to water, although they are generally not very water soluble. Injecting the solution through a syringe and fine gauge needle under the water in the container used for euthanizing is helpful in ensuring dispersal in the water. Doses of > 5 to 20 mL/L can be used (10 times the upper range for anesthesia). However, because both anesthetics are highly volatile, human safety is of concern and use in a well-ventilated area is imperative.

(6) Quinaldine sulfate. Solutions for immersion should be prepared in concentrations of 100 mg/L. Quinaldine sulfate will acidify water; therefore, buffering is required to prevent distress from acute drop in pH.

(7) Tricaine methanesulfonate, buffered (MS 222, TMS). Solutions must be buffered, and concentrations required for euthanasia may vary depending upon the species, life stage, and water chemistry parameters. A concentration of 250 to 500 mg/L, or 5 to 10 times the anesthetic dosage, is effective for most species. MS 222 at a dose of 400 mg/L has been shown to be ineffective for a few species (eg, Gulf of Mexico sturgeon). Finfish that are too large for practical or cost-effective immersion in lethal doses of buffered MS 222 can be euthanized by applying the concentrated, buffered solution directly to the gills.

(8) 2-phenoxyethanol. Solutions for immersion should be prepared in concentrations of 0.5 to 0.6 mL/L or 0.3 to 0.4 mg/L.

Injection—Injectable agents have been administered for euthanasia via IV, intracoelomic, IM, and intracardiac routes.

(1) Pentobarbital (1 step). Sodium pentobarbital (60 to 100 mg/kg [27.3 to 45.5 mg/lb]) can be administered by IV, intracardiac, or intracoelomic routes for euthanasia. Pentobarbital may also be administered via intracardiac injection for anesthetized animals as the second step of a 2-step euthanasia procedure. Death usually occurs within 30 minutes.

(2) Ketamine (2 step). Ketamine may be administered at dosages from 66 to 88 mg/kg (30 to 40 mg/lb) via an IM injection followed by a lethal dose of pentobarbital. Observers should be advised about the possibility of ketamine-induced muscle spasms during induction.

(3) Ketamine:medetomidine (2 step). A combination of ketamine, at dosages of 1 to 2 mg/kg, with medetomidine, at dosages of 0.05 to 0.1 mg/kg (0.02 to 0.05 mg/lb), may be administered via IM injection followed by a lethal dose of pentobarbital.

(4) Propofol (2 step). A dose of 1.5 to 2.5 mg/kg (0.7 to 1.1 mg/lb) can be administered IV followed by an injection of a lethal dose of pentobarbital.

S6.2.2 Physical Methods

The following methods can be applied for euthanasia, providing they are performed using proper equipment by trained personnel who are regularly monitored for proficiency.

(1) Decapitation followed by pithing (2 step). Rapid severance of the head and brain from the spinal cord, followed by pithing of the brain, will cause rapid death and unconsciousness. Decapitation alone is not considered a humane approach to euthanasia, especially for species that may be particularly tolerant of low O concentrations. Pithing helps ensure rapid loss of brain function and death for those species.

(2) Cervical transection using a knife or other sharp instrument inserted caudal to the skull to sever the spinal cord and cervical vertebrae, followed by pithing (2 step). The rationale for this approach is similar to that for decapitation (destruction of connections between brain and spinal cord) and pithing (destruction of brain tissue), except that the head is still physically attached by musculature to the body.

(3) Manually applied blunt force trauma (cranial concussion) followed by pithing (2 step). Manually applied blunt force trauma (a rapid, accurately placed blow of sufficient energy to the cranium with an appropriate-sized club) can cause immediate unconsciousness and potentially death, but should be followed by pithing to ensure death. The finfish’s size, species, and anatomy and characteristics of the blow (including its accuracy, speed, and club mass) will determine the efficacy of manually applied blunt force trauma. This procedure requires training and monitoring for proficiency. Anatomic features, such as the location of the eyes, can help serve as a guide to the location of the brain.

(4) Captive bolt (most commonly nonpenetrating; 1 step). This is a method usually applied to large finfish species.

(5) Maceration (1 step). When applied correctly, using a well-maintained macerator specifically designed for the size of finfish being euthanized, death is nearly instantaneous. The process is aesthetically unpleasant for some operators and observers.

(6) Rapid chilling (hypothermic shock; 1 step or 2 step). It is acceptable for zebrafish (D rerio) to be euthanized by rapid chilling (2° to 4°C) until loss of orientation and operculum movements and subsequent holding times in ice-chilled water, specific to finfish size and age. Zebrafish adults (approx 3.8 cm long) can be rapidly killed (10 to 20 seconds) by immersion in 2° to 4°C (36° to 39°F) water. Adult zebrafish should be exposed for a minimum of 10 minutes and fry 4 to 7 dpf for at least 20 minutes following loss of operculum movement. Use of rapid chilling and use of buffered MS 222 alone have been shown to be unreliable euthanasia methods for zebrafish embryos < 3 dpf. To ensure embryonic lethality these methods should be followed with an adjunctive method such as use of dilute sodium or calcium hypochlorite solution at 500 mg/L. If necessary to ensure death of other life stages, rapid chilling may be followed by either an approved adjunctive euthanasia method or a humane killing method. Until further research is conducted, rapid chilling is acceptable with conditions for other small-bodied, similarly sized tropical and subtropical stenothermic species. Species-specific thermal tolerance and body size will determine the appropriateness and effectiveness of rapid chilling for euthanasia of finfish. Finfish size is important because the rate of heat loss via thermal conduction from a body is proportional to its surface area. Based on these 2 factors, it has been suggested that rapid chilling in water associated with an ice slurry is a suitable killing method for small tropical and subtropical finfish species 3.8 cm in length (tip of the snout to the posterior end of the last vertebra) or smaller, having lower lethal temperatures above 4°C.

To ensure optimal hypothermal shock (ie, rapid killing), transfer of finfish into ice water must be completed as quickly as possible. This means rapid transitions from acclimatization temperature to 2° to 4°C must be achieved. This can be accomplished by using minimal water volume to transfer finfish (ie, using a net to place finfish in chilled water). In addition, finfish should not be in direct contact with the ice in the water; rather a depression should be formed in the ice slurry to expose the entire surface of the finfish to the chilled water. Full contact with cold water ensures optimal exposure and rapid chilling of the finfish. Water temperature must not exceed 2° to 4°C. Well-insulated containers, such as coolers, will assist in maintaining the ice slurry and a probe thermometer can be used to confirm water temperature.

This method of euthanasia is not appropriate for temperate, cool, or cold-water–tolerant finfish, such as carp, koi, goldfish, or other species that can survive at 4°C and below. It is appropriate for zebrafish and other small-bodied (3.8-cm-long or smaller) tropical and subtropical stenothermic finfish, for which the lower lethal temperature range is above 4°C. This method can also be acceptable for small to medium-sized (2.8to 13.5-cm-long) Australian river gizzard shad, as long as secondary euthanasia methods are applied after finfish are rendered nonresponsive.316 However, because of surface-to-volume considerations, use of this method is not appropriate in other medium to large-bodied finfish until data regarding its applicability to euthanasia for those species become available.

S6.2.3 Adjunctive Methods

Decapitation, pithing, freezing, and other physical methods for inducing death may be used as the second step of a 2-step procedure when finfish have been rendered unconscious prior to their application by an acceptable or acceptable-with-conditions, first-step method. If necessary to ensure death, rapid chilling for specified groups may be followed by either an approved adjunctive euthanasia method or a humane killing method. Use of a dilute sodium hypochlorite or calcium hypochlorite solution may be an adjunctive method for early life stages of finfish, including embryos and larvae.

S6.2.4 Unacceptable Methods

The following are unacceptable methods of euthanasia in any situation. Flushing of finfish into sewer, septic, or other types of outflow systems is unacceptable for many reasons. Water chemistry and quality may delay time to death and result in exposure to noxious compounds. For systems in close proximity to and/or connected to natural waterways, pathogen release or transmission may occur from diseased or carrier animals. Slow chilling or freezing of unanesthetized animals, including placing finfish into a freezer without prior anesthesia, is also an unacceptable method. Similarly death by anoxia and dessication after removal from the water or by anoxia in water; any death due to exposure to caustic chemicals; and death including prolonged traumatic injury prior to unconsciousness are unacceptable.

While metomidate has been used for euthanasia of some finfish species, its listing in the Index of Legally Marketed Unapproved New Animal Drugs for Minor Species by the FDA (with a specified use for sedation and anesthesia) means that its extralabel use for euthanasia is currently illegal.

S6.2.5 Life Stage Considerations

The effectiveness of euthanasia methods described in these guidelines may vary by life stage, as well as by species. Early stages in the lives of finfish, including embryos and larvae, may require higher concentrations of immersion anesthetics or a longer duration of exposure. As an example, immersion in a buffered MS 222 solution having a concentration > 1 g/L is not a reliable method for killing some finfish in younger life stages. For some species and in some situations, adjunctive methods to guarantee death may need to be applied for these animals after anesthesia with buffered MS 222. Rapid chilling followed by an adjunctive method such as immersion in a dilute sodium hypochlorite or calcium hypochlorite solution is acceptable for zebrafish embryos and larvae as a 2-step method and is also acceptable with conditions as a 2-step method for destruction of other (nonzebrafish) species’ embryos and larvae.

S6.2.6 Finfish in Particular Environments

S6.2.6.1 Veterinary Private Practice— Companion and ornamental (Display) Finfish

Clients with pet or display finfish of any species often value them as companion animals and share a human-animal bond similar to that seen between clients and other pets, such as dogs and cats. Therefore, it is important to consider the perception of the client when euthanasia methods are chosen. Clients should be offered the opportunity to be present during euthanasia whenever feasible; however, clients also should be educated as to what method will be used and what they may observe during euthanasia. For example, clients may believe the excitement phase of anesthesia, which can result in increased motor activity or the appearance of agitation, is unduly painful or stressful for the finfish even when it is not.

The following methods are acceptable for use in this environment:

(1) Immersion in solutions of buffered tricaine methanesulfonate (MS 222), buffered benzocaine, isoflurane and sevoflurane, quinaldine sulfate, and 2-phenoxyethanol.

(2) Injections of pentobarbital, ketamine followed by pentobarbital, a combination of ketamine and medetomidine followed by pentobarbital, and propofol followed by pentobarbital. Owners should be advised about the possibility of ketamine-induced muscle spasms during induction when using that agent.

The following methods are acceptable with conditions for use in this environment:

(1) Immersion in eugenol, isoeugenol, or cloveoil. Finfish should be left in the solution for a minimum of 10 minutes after cessation of opercular movement.

The following methods are not recommended for use in this environment:

(1) Immersion in CO2-saturated water is not recommended because some finfish exposed to this method may become hyperactive, which can be disconcerting for staff and owners.

(2) Manually applied blunt force trauma to the head, decapitation, and pithing are not recommended because their application can be distressing for owners and staff.

Early stages in the lives of finfish, including embryos and larvae, may require higher concentrations of immersion anesthetics or a longer duration of exposure. As an example, immersion in a buffered MS 222 solution having a concentration > 1 g/L is not a reliable method for killing some finfish in early life stages. For some species and in some situations, adjunctive methods to guarantee death may need to be applied for these animals after anesthesia with buffered MS 222.

Rapid chilling followed by immersion in a dilute sodium hypochlorite or calcium hypochlorite solution is acceptable for zebrafish embryos and larvae as a 2-step method and is also acceptable with conditions as a 2-step method for destruction of other (nonzebrafish) species’ embryos and larvae.

S6.2.6.2 Aquarium Finfish Wholesale and Retail Facilities

Freshwater and marine aquarium finfish are commercially collected from the wild, and are also bred in captivity. Tropical aquarium finfish are sold at retail pet shops and finfish stores from systems housing one or more species of finfish per tank. Individual finfish or populations of finfish may become injured or diseased and require euthanasia. Methods of euthanasia used in this environment need to be applicable to individual finfish, to all finfish in an aquarium, to finfish held in multiple aquariums on a central filtration system, or for finfish kept in ponds. In certain situations euthanasia may not be feasible and depopulation methods may be required.

The following methods are acceptable for use in this environment:

Immersion in solutions of buffered tricaine methanesulfonate (MS 222), buffered benzocaine, and quinaldine sulfate. Finfish should be left in the anesthetic solution for a minimum of 10 minutes after cessation of opercular movement.

The following methods are acceptable with conditions for use in this environment:

(1) Immersion in CO2-saturated water; eugenol, isoeugenol, or clove oil; and ethanol.

(2) Decapitation, cervical transection, or manually applied blunt force trauma as step 1 of a 2-step method, followed by pithing.

(3) Freezing may be used as an adjunctive method following anesthesia.

(4) Rapid chilling (hypothermic shock) for small-bodied (3.8-cm-long or smaller) tropical and subtropical stenothermic finfish, for which the lower lethal temperature range is above 4°C.

The following methods are not recommended for use in this environment:

Use of injectable anesthetic drugs including barbiturates, requires the oversight of a veterinarian and DEA permitting for controlled substances. Therefore, unless a veterinarian is available on-site to oversee use of these drugs, this method is not recommended in this environment.

Early stages in the lives of finfish, including embryos and larvae, may require higher concentrations of immersion anesthetics or a longer duration of exposure. As an example, immersion in a buffered MS 222 solution having a concentration > 1 g/L is not a reliable method for killing some finfish in early life stages. For some species and in some situations, adjunctive methods to guarantee death may need to be applied for these animals after anesthesia with buffered MS 222.

Rapid chilling followed by immersion in a dilute sodium hypochlorite or calcium hypochlorite solution is acceptable for zebrafish embryos and larvae as a 2-step method and is also acceptable with conditions as a 2-step method for destruction of other (non-zebrafish) species’ embryos and larvae.

S6.3 AQUATIC INVERTEBRATES

Overdose of a general anesthetic is as appropriate a euthanasia strategy for aquatic invertebrates as it is for finfish. And, immersion is an effective route of administration of anesthetic and euthanasia agents.
Because confirming the death of many invertebrates is difficult, 2-step euthanasia procedures are often recommended in which chemical induction of anesthesia, nonresponsiveness, or presumptive death is followed by an adjunctive method that destroys the brain or major ganglia physically (eg, pithing, freezing, boiling) or chemically (eg, alcohol, formalin). Application of the latter methods by themselves is generally not considered to meet the criteria established for euthanasia.

S6.3.1 Acceptable First Steps of 2-Step Methods
S6.3.1.1 noninhaled Agents for Immersion

Magnesium salts—Magnesium salts are a near-universal anesthetic agent, relaxing agent, and euthanasia agent for aquatic invertebrates, although they are ineffective for crustaceans. A range of concentrations has been recommended for various phyla. Research suggests the magnesium ion acts centrally in suppressing neural activity of cephalopods.


Clove oil or eugenol—Clove oil or eugenol has been used effectively as an immersion agent for the euthanasia of crustaceans (0.125 mL/L). Isoeugenol is a potential carcinogen so human safety in the application of that agent is of concern.

Ethanol—Ethanol has been used for euthanasia of some phyla (at a 1% to 5% concentration as compared with concentrations of > 70% used for preservation), and acts by inhibiting neuronal sodium and calcium channels in molluscs. Initial aversion and/ or excitement has been reported as occurring in cephalopods.

Other agents for euthanasia, while less common, have been described and may be useful for specific applications.

S6.3.2 Acceptable Second Steps of 2-Step Methods

S6.3.2.1 noninhaled Agents for Immersion

Noninhaled agents that can be administered via immersion as the second step of a 2-step euthanasia approach include 70% alcohol and neutral-buffered 10% formalin. These agents are not acceptable, however, for immersion as a single-step procedure, nor as the first step of a 2-step procedure.

S6.3.2.2 Physical Methods
Pithing, freezing, and boiling are acceptable as the second step (adjunctive methods) of a 2-step euthanasia procedure. Pithing requires detailed anatomic knowledge of the species in question. These methods are not acceptable, however, as a single-step procedure, nor as the first step of a 2-step procedure.

S6.3.3 Life Stage Considerations

The effectiveness of euthanasia methods described in the Guidelines may vary depending on life stage and species. As for finfish, this should be considered when euthanizing aquatic invertebrates. Methods used for different life stages of the same species may require modification to maximize their effectiveness. Recommendations regarding use of adjunctive methods (as described previously) may also be necessary to guarantee death.

S6.3.4 Unacceptable Methods

Methods of killing that do not cause rapid death or that cause trauma prior to loss of consciousness are not considered humane methods of death, or euthanasia.

These can include removing a finfish or aquatic invertebrate from the water and allowing it to die by hypoxia secondary to desiccation of gill tissue; leaving finfish or aquatic invertebrates in a container of water without adequate aeration, causing death by anoxia; or any death due to exposure to caustic chemicals or traumatic injury without first inducing unconsciousness in the finfish or aquatic invertebrate.

Post Fri Mar 01, 2013 2:11 pm
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Thanks nelson. Its a tough subject, but one that nearly every fishkeeper has to deal with at some point. Good to be aware of the best methods.
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Post Fri Mar 01, 2013 3:24 pm
rawalstrom Level 3 Member
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Thanks for the post. This is my least favorite part of fish keeping.

But... I would require training for blunt force trauma?? :P

Ryan
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Post Fri Mar 01, 2013 3:53 pm
nelson23 Level 2 Member
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But... I would require training for blunt force trauma?? :P

I may be able to handle that part without training. A lot of the things listed an average person cannot get their hands on, but cloveoil, MS 222, and 95 to 100% ethanol are all readily available, as well the physical methods. I just think that a lot of us really get to know our fish over time and want to do right by them. Hopefully this can help people euthanize humanely and not feel as bad about it afterwards, because they know they did something in a good way.

Post Sat Mar 02, 2013 11:10 pm
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nelson23 wrote:
A lot of the things listed an average person cannot get their hands on, but cloveoil, MS 222, and 95 to 100% ethanol are all readily available, as well the physical methods. I just think that a lot of us really get to know our fish over time and want to do right by them. Hopefully this can help people euthanize humanely and not feel as bad about it afterwards, because they know they did something in a good way.


Thanks for breaking it down to these three methods. This document requires a considerable amount of time and attention. Us older folks used to have ADHD but our health has improved with age and now just have ADD. It is still difficult to wade through it.
Like a complete unknown

Post Sun Mar 03, 2013 12:31 pm
ibleeg Level 3 Member
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Can someone summarize it in a less lengthy way???plz

Post Tue May 07, 2013 10:02 pm
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ibleeg wrote:
Can someone summarize it in a less lengthy way???plz


clove oil will kill your unwanted fish in a humane fashion. It is easy to get(obtain).
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Post Wed May 08, 2013 3:48 am
musserjoe User avatar
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I am all for not causing any creature any unnecessary harm.

That being said, as an avid fisherman I would say that at least once a month, one of my favorite things is fish battered and deep fried.

There is just no possible way I am going to 'humanely euthanize' these fish.

While I am not going out of my way to torture my meal, also I would say that any of the described methods are completely out of the question.

I hate to be insensitive but my reaction to this article: :roll:

Post Wed May 08, 2013 8:39 pm
Passionfish Level 20 Member
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Posts: 12302
Location: apple valley, mn
nelson23 wrote:
In case anyone is interested in 2013 the American Veterinary Medical Association (AVMA) updated the Guidelines
for the Euthanasia of Animals:


Specific to finfish, the three main terms used to describe the ending of life are euthanasia, slaughter, and humane killing. There is often confusion regarding how these terms and their associated methods differ. The methods described in the Guidelines serve as guidance for veterinarians and others who may need to perform euthanasia. The Guidelines are not intended to specifically address slaughter or humane killing methods. Slaughter is used primarily to describe the humane killing of animals intended for human consumption for food or other uses (eg, agricultural harvest, commercial fishing). Humane killing is less specific and can be used to describe some recreational fishing practices and may also include activities such as finfish sampling, depopulation, eradication, and control to eliminate unwanted finfish (including diseased or nonnative finfish) from a water body. A fourth term, harvest, specifically refers to the act or process of gathering a crop, as in aquaculture and commercial fishing; however, harvest may also be used to describe finfish removed from a water body by anglers. Whether harvested finfish are slaughtered or humanely killed depends on the context of the activity. Neither slaughter nor humane killing is addressed by this document.

S6.1.6 Finfish and Aquatic Invertebrates Intended for Human Consumption

As previously indicated, the term slaughter is used primarily to refer to the killing of animals intended for human consumption (eg, agricultural harvest, commercial fisheries) and these Guidelines are not intended to address that activity. However, when euthanasia of animals intended for human consumption is desired, tissue residues from the use of drugs and other chemicals will make many methods unacceptable unless they have been approved by the FDA for this purpose and appropriate withdrawal periods are followed. Use of any unapproved chemicals for euthanasia prohibits entry of the finfish into the food chain, either by rendering, as fish meal, or as directly consumed product.549 With that said, currently there are no drugs approved for euthanasia of finfish or aquatic invertebrates. Carbon dioxide is a drug of low regulatory priority that avoids unacceptable residues, but it is not an FDA approved method for killing aquatic animals used for food. Physical methods that are acceptable with conditions include manually applied blunt force trauma to the head, decapitation, and pithing.
Like a complete unknown

Post Sun Sep 08, 2013 10:38 am
Omaknits User avatar
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Location: St Paul, MacGroveland
Can anyone describe what "pithing" is? I am the head fish cleaner in my family and it still does bother me to be fileting fish that appear to still be alive. I says that decapitation is acceptable if followed by pithing.

Post Sun Sep 08, 2013 12:53 pm
Passionfish Level 20 Member
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Location: apple valley, mn
pithing is placing metal or hard plastic rod through interior of spinal column and sliding it caudally the length of spinal column, it can only be accomplished if spinal column has been seperated first to allow rod entry into column interior

pithing will destroy motor neurons resulting in no futher movement or flopping about by decapitatied fish, sensory neurons will continue to recieve messages from sensory receptors but the information can no longer be transmitted to motor neurons or brain neurons
Like a complete unknown

Post Sat Dec 21, 2013 4:16 am
AZNboi Level 1 Member
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Location: Sant Paul
Passionfish wrote:
pithing is placing metal or hard plastic rod through interior of spinal column and sliding it caudally the length of spinal column, it can only be accomplished if spinal column has been seperated first to allow rod entry into column interior

pithing will destroy motor neurons resulting in no futher movement or flopping about by decapitatied fish, sensory neurons will continue to recieve messages from sensory receptors but the information can no longer be transmitted to motor neurons or brain neurons

We do that to cows at slaughter house. Quick an easy no pain

Post Sat Dec 21, 2013 4:40 am
Passionfish Level 20 Member
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Posts: 12302
Location: apple valley, mn
I worked at slaughter house.
The device used there is a captive bolt pistol or stun gun, bolt gun or cattle gun. In devices where bolt enters brain, part of brain is destroyed and there is a concussion injury that knocks the animal out. Penatrating rod style stun gun is falling out of favor as disease from one cow brain is transmitted to next cow brain. Currently most stun guns strike forehead causing a severe concussion but do not force a rod into cranium. Animal is not dead and is most definitely is not pithed. Brain stem remains intact and animals heart is beating. This is important as next step is to bleed the animal and a beating heart is necessary for good bleed.
Like a complete unknown

Post Fri Feb 14, 2014 2:36 pm
Fortune User avatar
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Location: South St. Paul
Can we get a tl;dr?
Image

Post Sat Feb 15, 2014 1:31 pm
Passionfish Level 20 Member
Level 20 Member

Posts: 12302
Location: apple valley, mn
Cliff's notes version:
Use MS-222 at appropriate conc.
Use clove oil at appropriate conc
Create water/ice bath at temperature just above 32 degrees F
Like a complete unknown

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