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Species Identification in Fish and Wildlife Forensic Investigations

A wide variety of forensic techniques are presently available to Florida Fish and Wildlife Conservation Commission (FWC) officers investigating violations against Florida’s fish and wildlife resources. As new scientific advances are used in forensic analysis, the number, capabilities, and potential for use of these techniques are constantly increasing.

During investigation of fish and wildlife crimes, law enforcement officers encounter different types of physical, chemical, and biological evidence. Effective use of forensic analysis enhances the ability of investigators to determine if violations have occurred, how, and by whom the violations were committed. Investigators can then establish links between crime scenes, evidence, and suspects.

Physical evidence include fibers, soil, glass, firearms, tools, footprints and other impressions, tool marks, and other materials.  Chemical evidence includes gunshot residue, drugs, flammable materials, fragrances, poisons, and other substances.  When identified and properly collected, these types of evidence are submitted and analyzed by specialized criminology forensic laboratories. FWC officers and investigators usually submit physical and chemical evidence to the Florida Department of Law Enforcement’s (FDLE) Forensic Laboratory. FDLE has many facilities around the state that specialize in different types of evidence that include physical, chemical, and biological.  

Biological evidence is anything that is or has been a part of a living organism. This category includes tissues, meat, body fluids, skin, fur, hair, bones, scales, internal organs, and other animal parts or remains. This type of evidence can be analyzed to identify any type of individual animal species or gender, the location where a particular animal or population is from, the cause, time and manner of death, and other information. Methods include morphological examination (which means examining the form and structures that are unique to different species), dissection of carcasses, and the use of chemical and biochemical analyses.

Species identification is possible in virtually all living organisms including plants. It can be accomplished in many ways using a variety of techniques. The methods chosen depend on several factors including the type of sample collected by the officer, the condition of the sample, and what information is necessary to support an investigation or to demonstrate that a violation has occurred.  In many instances an officer or a biologist can visually identify an organism or identify it by referencing published guides and manuals used for the identification of specific groups of animals. Law enforcement officers receive training on how to conduct species identification in the field. Additionally, the FWC’s Fish and Wildlife Research Institute (FWRI) has many biologists who are experts in specific groups of animals and routinely conduct identifications based on visual examination of animals as well as parts and remains.

Morphological examination is best suited for samples such as hairs, feathers, hide, skeletal remains, whole or partial carcasses, small parts of animals such as fish scales, feathers, legs, tails, and bones, birds, fish, fish fillets, and other animal remains often left behind by poachers, hunters, anglers, and other animals that prey on a particular species. Using the naked eye or a microscope, the evidence sample is studied and then compared to reference samples or compared to published works such as identification guides, manuals, and publications dedicated to individual species.

Morphological examination cannot be used for samples that have no visually recognizable features.  These samples include body fluids such as blood, sweat, and other secretions.  Other samples with no recognizable features include pieces of meat, fragments of other tissues, and samples that have been destroyed or otherwise altered by physical processes such as weather, or other factors. These kinds of samples require more complicated scientific analysis that often requires specialized laboratory facilities. Current methods for these identifications include chemical and biochemical identification of compounds found in blood and other animal tissues. These techniques identify proteins, genetic material, and other molecules that are unique to different species of animals.

Species identification techniques have been used on many kinds of samples, including fish scales, internal organs, skins, and hides intended for the manufacture of clothing. Species identification has also been used on feathers from protected birds. Biochemical and molecular techniques have been useful to determine whether or not blood, body fluids, meat, and other samples obtained from crime scenes came from a particular species.

In a recent case, a known poacher was charged with illegal possession of a snook during a closed season. When confronted by the officer, the suspect emptied a bucket that contained a fish. The officer believed that the suspect’s bucket contained a snook out of season. Without the fish as evidence, the officer needed to demonstrate that the suspect had been in possession of a snook.  The officer seized the bucket as well as the suspect’s fishing tackle. Six fish scales and fish slime containing blood were found in the bucket. The scales were examined and compared to reference samples. The blood was subjected to DNA analysis. Test results of the samples demonstrated they came from a snook, thus confirming that suspect had been in illegal possession of a snook. In addition to charges of possession of a snook during the closed season, the suspect was found guilty of tampering with evidence, a second degree felony.

As research at FWRI continues yielding more information about specific animals being studied, species identification will continue to improve as a tool to enforce the laws and regulation that protect the state’s fish and wildlife resources. Scientists and law enforcement officers constantly seek to improve their abilities and work together towards supporting the mission of the Florida Fish and Wildlife Conservation Commission:

 “Managing fish and wildlife resources for their long-term well-being and the benefit of people.”