Management of non-fatal human crocodile interaction with Crocodylus moreletii in the Laguna del Carpintero, Tampico, Mexico

Human-crocodile interaction in the Laguna del Carpintero, Tampico, Tamaulipas, Mexico has been a growing concern for the last several years, with homeless people being the most affected in recent years, however, productive people have also been involved. The objective of this document is to describe in detail a case of non-fatal human-crocodile interaction in this lagoon and the response of the SOS Crocodile Tampico working group. To document the case, we collected information on the interaction, the causative crocodile and the affected person. On June 8, 2024 a male person was involved in a non-fatal interaction with a 278 cm long crocodile, which caused a fracture in his left leg, requiring him to be transported to the nearest hospital. This event activated the first response team who provided pre-hospital and hospital care; search and capture of the crocodile involved, as well as the custody, handling and final disposal of the crocodile into captivity. Therefore, we consider that inter-institutional coordination between federal, state, municipal, health and crocodile specialists, integrated as the SOS Crocodile working group, is fundamental to rapidly and efficiently attend the interactions with crocodiles in urban areas.

SOS Crocodile working group, Morelet´s crocodile, Negative interaction, First response protocol.

The frequency of negative interactions between humans and crocodiles is increasing as a

of the expansion of urban areas, which is leading to the isolation of nearby wetlands and direct competition for space, water, and food resources (Amarasinghe et al. 2015). The city of Tampico, Tamaulipas (Mexico) plays an important role in the state's economy as a tourist destination, with the Laguna del Carpintero being a primary attraction for visitors. The tourist activity in this lagoon has experienced exponential growth over the past two Author-formatted, not peer-reviewed document posted on 25/11/2024. DOI:  https://doi.org/10.3897/arphapreprints.e142593 Non-fatal human crocodile interaction in Mexico 2 decades, with a diverse range of recreational, sporting, and cultural activities taking place. The site boasts an array of recreational facilities, including a park, fairground, theatre, convention center, sports unit, schools, and a semi-conserved natural area (Figure 1). The site is home to a population of swamp crocodiles (Crocodylus moreletii) that has been studied since 2004. Previous research has indicated that the population is ecologically stable and functional (Carrera 2004; Villegas and Reynoso 2013; Rivera-Téllez et al. 2017). The crocodiles are the primary tourist attraction of the lagoon, and the municipality offers guided trips on outboard motorboats (pontoons) and trams for visitors to observe the crocodiles at their leisure, whether they are swimming or sunbathing in their natural habitat. Regarding non-fatal human-crocodile encounters (IH-C), it is notable that 25% of such incidents recorded in the state of Tamaulipas occur in Tampico City. The Laguna del Carpintero accounts for 100% of IH-C NF occurrences within this municipality (Cedillo- Leal et al. 2024). In light of these circumstances, the municipality of Tampico initiated an interdisciplinary project in 2020, with the objective of addressing the crocodile population in Laguna del Carpintero. The project's primary objective was the formation of a first response team, designated as "SOS Crocodile Tampico," which included experts from various government agencies, including federal, state, and municipal representatives, as well as specialists in crocodile management, medical professionals, and first aid personnel. This working group adheres to the recommendations set forth in the Protocol for Attention to Human-Crocodile Contingencies (PACH-C) (SEMARNAT, 2018), a document developed by Mexican specialists to address this type of contingency. The PACH-C outlines the recommended courses of action for the resolution of IH-C in Mexico. The

of this group is to address all reports of interactions with crocodiles, including both sightings and instances of non-fatal and fatal attacks. In this context, the SOS Crocodile Tampico working group is responsible for the design and proposal of preventive strategies, including the installation of signage along the entire periphery and canals of the lagoon, as well as the organization of talks and training workshops for authorities, civil society, and students from a range of educational levels. These workshops aim to highlight the importance of crocodiles and the prevention of negative interactions. Furthermore, it coordinates surveillance and dissemination actions on radio, television and social networks (Barrios-Quiroz et al. 2021). Regrettably, despite the implementation of preventive strategies and corrective actions, negative interactions with crocodiles were documented during the initial three-year phase of the project (2021-2023), with all cases involving homeless individuals (Cedillo-Leal et al. 2023). In the current year, 2024, for the first time since the project's implementation, two of the three negative interactions that have occurred involved individuals who are not homeless. The purpose of this document is, therefore, to present in detail the response and coordinated actions of the SOS Crocodile Tampico working group to a case of non-fatal human-crocodile interaction in the Laguna del Carpintero.

The following case study documents an interaction between humans and crocodiles that occurred in 2024 in Laguna del Carpintero, located in Tampico, Tamaulipas, Mexico (Fig. 1). The first author gathered data regarding the location of the incident (GPS, WGS84 system), as well as the date and time of the incident. The incident was classified in Author-formatted, not peer-reviewed document posted on 25/11/2024. DOI:  https://doi.org/10.3897/arphapreprints.e142593 Non-fatal human crocodile interaction in Mexico 3 accordance with the criteria set forth in the Protocol for Attention to Human-Crocodilian Contingencies (PACH-C) (SEMARNAT, 2018). Additionally, data pertaining to the crocodile, including its sex and total length, were obtained. Information regarding the victim, such as age, sex, social status, and the injuries caused by the crocodile, number and type, was also collected.

The following section presents a detailed account of the case in question. On June 8, 2024 at 21:00, a report was received via the 911 emergency services hotline. The caller indicated that a person had been bitten by a crocodile in the vicinity of Laguna del Carpintero (22° 13.776'N; 97° 50.883'W). In response to this report, an alert was promptly disseminated to members of the SOS Crocodile Tampico working group, who were then instructed to initiate the PACH-C protocol (SEMARNAT, 2018). The group personnel (municipal firefighters, state guardsmen, Mexican Red Cross members, and the group's coordinator) promptly proceeded to the site to verify the report. The individual was identified as an adult male and was observed to have crawled a distance of approximately 102 meters from the site of the incident. He was subsequently provided with pre-hospital care by Mexican Red Cross paramedics (Fig. 2A-B) and was then transferred to the Tampico General Hospital "Dr. Carlos Canseco," where the emergency team was already waiting to provide further care. It is noteworthy that the initial response group actively communicates with the Author-formatted, not peer-reviewed document posted on 25/11/2024. DOI:  https://doi.org/10.3897/arphapreprints.e142593 Non-fatal human crocodile interaction in Mexico 4 hospital personnel responsible for providing subsequent care. This enables the transfer of essential information, including the initial report and photographs of the wounds, allowing for a pre-diagnosis and improved preparation for the eventual reception of the victim. Following the victim's admission to the medical facility, the incident was classified as Grade 4 (non-fatal) (PACH-C). Thereafter, an incident order was initiated, which outlined the recommended strategies and activities to be conducted in accordance with the degree of interaction. Subsequently, the site where the interaction took place was identified and classified as an open rainwater drainage channel with closed vegetation in the majority of the channel. This channel is situated between the municipal sports facility and the fairgrounds (Fig. 1). The site in question is adjacent to a dirt road that is routinely utilized by the residents of the area for commuting to and from their places of employment. The exact location of the incident was determined due to the presence of blood and footwear belonging to the victim, in addition to the observation of an adult crocodile in the vicinity, which exhibited a peculiar behavior as it emerged from the water when it perceived our presence (Fig. 2C). Subsequently, we conducted a survey to determine if additional crocodiles were present, during which we observed a second, smaller crocodile at a distance of 42 meters from the site of the interaction. This second crocodile was identified as a nesting female (Fig. 2D). Previously, the nest had been manipulated to translocate the eggs on May 23, 2024, and the nest was destroyed for safety reasons. However, the female constructed a new nest without the presence of eggs (Fig. 2D). Author-formatted, not peer-reviewed document posted on 25/11/2024. DOI:  https://doi.org/10.3897/arphapreprints.e142593 Non-fatal human crocodile interaction in Mexico 5 The crocodile that caused the interaction was captured using poles, specifically a PVC tube with a plastic-lined steel cable, which were placed in the crocodile's neck. The capture process was completed in approximately two hours, as the crocodile was introduced into a subway cave, a characteristic habitat of this species. Subsequently, the animal was transported to the facilities of the municipal fire department, where it was temporarily housed, and the relevant data was collected (Fig. 3A-C). The crocodile was identified as a male Crocodylus moreletii, measuring 278 cm in total length. It was transferred to the federal authority (PROFEPA) who placed it in permanent captivity to prevent further incidents. A follow-up interview was conducted with the victim and the medical staff of the hospital to obtain further information regarding the circumstances of the incident, including the number and severity of injuries inflicted by the crocodile. The victim was a 54-year-old adult male who stated that he was not intoxicated or under the influence of any illicit substance. He also indicated that he was a regular visitor to the area, where he was watching a soccer game at the time of the incident. He had decided to walk to the edge of the canal to urinate when the attack occurred. At that moment, the crocodile seized the individual by the left leg, above the knee, inflicting a substantial injury. During his attempt to defend himself, he suffered a minor injury to his right hand. The medical report from the emergency department indicated the presence of a 15 cm avulsive wound with irregular edges in the quadriceps femoris, accompanied by exposure Author-formatted, not peer-reviewed document posted on 25/11/2024. DOI:  https://doi.org/10.3897/arphapreprints.e142593 Non-fatal human crocodile interaction in Mexico 6 of muscle tissue and fracture of the left femur. Consequently, the patient was admitted to the operating room for surgical lavage and trauma surgery, with the objective of placing external fixators and reconstruction of the muscle tissues. The patient was hospitalized for a period of three days and subsequently discharged for recovery at home until the removal of the external fixator, after which he was referred for physiotherapy sessions.

This is the first documented incident of a non-homeless individual engaged in a negative encounter with a crocodile in the Laguna del Carpintero since the inception of the SOS Crocodile Tampico working group. It is suggested that this interaction may have been triggered by a number of factors. Primarily, the time of day may have been a contributing factor. While the majority of these events are recorded during daytime hours (Langley, 2010), this case was recorded at night. This could have prevented the individual from observing the presence of the crocodile at the site. However, the victim stated during his interview that he was aware of the presence of crocodiles in the area and had observed them basking in the channel on multiple occasions. This assertion is corroborated by the first author of this manuscript, who has observed that male crocodiles are frequently found at close distances (less than 50 m) from the nests and, like the nesting females, they are vigilant at a distance from the nesting area. This finding is consistent with the data collected during the investigation of this case, which revealed that the interaction occurred at a distance of 42 meters from a nest. It is noteworthy that this incident coincided with the reproductive season of the species (April to September), during which the greatest number of interactions are observed. This finding concurs with national and worldwide statistics (Brien et al. 2017; García-Grajales and Buenrostro-Silva 2018; Khan et al. 2020). The creation of a first response task force to address negative interactions between humans and crocodiles has the potential to be a critical factor in preventing severe outcomes for victims. The communication between the various actors within this group enables a reduction in the time elapsed between the incident and the provision of hospital care. As soon as the SOS Crocodile Tampico working group is alerted, the emergency area is already aware and can evaluate the type of injury in advance. This is achieved through the information and images sent from the site of the incident, ensuring that the necessary material, area and personnel are prepared to attend the case.

The SOS Crocodile working group is a collaborative network of governmental agencies at the federal, state, and municipal levels, in addition to healthcare professionals and crocodile experts. This working group is becoming an invaluable resource in the resolution of the socio-environmental challenge of managing human-crocodile interactions. The increase in crocodile sightings and interactions with humans has been exacerbated by the process of urbanization, which is encroaching upon the crocodile habitat. In Tampico, the proximity of the Laguna del Carpintero and the consequent increase in human activity has heightened the risk of negative encounters with the crocodile, which is now regarded as a potentially dangerous animal. Despite the animal's dangerous reputation, however, it also evokes feelings of fascination and interest among people. The work of the SOS Crocodile Tampico working group, therefore, extends beyond the provision of victim care in the event of an attack. It also aims to foster awareness of the importance of coexistence with this reptile, Author-formatted, not peer-reviewed document posted on 25/11/2024. DOI:  https://doi.org/10.3897/arphapreprints.e142593 Non-fatal human crocodile interaction in Mexico 7 which play a fundamental role in maintaining the ecological balance within the wetlands they inhabit.

We would like to express our gratitude to all members of the SOS Crocodile Tampico working group for their invaluable contributions to the human-crocodile interactions project. Our special thanks to the Tampico Fire Department, the Mexican Red Cross, and the emergency area of the General Hospital "Dr. Carlos Canseco" for their crucial role in this initiative. Furthermore, we extend our gratitude to the municipal administration of Tampico (2018-2024), with special acknowledgement to the Department of Ecology, for their pivotal role in the successful implementation of this project. Additional Information Incompatibility The authors declare that there is no conflicting of interest. Ethical Statement No ethics statement was reported. Funding This research did not receive any specific grants from funding agencies in the public, commercial, or nonprofit sectors. Authors' contributions César N. Cedillo-Leal: fieldwork, writing, original draft and revision. Gabriel Barrios-Quiroz: writing, revising, translating and editing. Sergio E. Padilla-Paz: writing, translation and editing. ORCID of the author César N. Cedillo-Leal: https://orcid.org/0009-0009-5711-8628 Gabriel Barrios-Quiroz: https://orcid.org/0009-0005-5663-9289 Sergio E. Padilla-Paz: https://orcid.org/0000-0001-6530-6658 Data availability Author-formatted, not peer-reviewed document posted on 25/11/2024. DOI:  https://doi.org/10.3897/arphapreprints.e142593 Non-fatal human crocodile interaction in Mexico 8 All data supporting the findings of this study are presented in the main text.

Amarasinghe AA, Madawala MB, Karunarathna DMS, Manolis C, De Silva A, and Sommerlad R (2015) Human – crocodile conflict and conservation implications of saltwater crocodiles Crocodilus porosus (Reptilia: Crocodylia: Crocodylidae) in Sri Lanka. Journal of Threatened Taxa 7: 7111 –7130. https://doi.org/10.11609/JOTT. O4159.7111-30 Barrios-Quiroz G, Cruz -Morales G and Cedillo -Leal CN (2021) Monitoring crocodylus moreletii in el Carpintero lagoon and establishment of “SOS Cocodrilo Tampico group” in Tamaulipas, México. Crocodile Specialist Group, Newsletter 40(1): 8-12. https://www.iucncsg.org/365_docs/attachments/protarea/09d0e0a5c4a731abd0e33 be60944bfd3.pdf Brien ML, Gienger CM, Browne CA, Read MA, Joyce MJ and Sullivan S (2017) Patterns of human –crocodile conflict in Queensland: a review of historical estuarine crocodile ( Crocodylus porosus ) management. Wildlife Research 44: 281 -290. https://doi.org/10.1071/WR17011 Carrera M (2004) Manejo integral de las poblaciones de cocodrilos en el municipio de Tampico. Memorias de la VI Reunión del Subcomité Técnico Consultivo COMACROM, Puerto Vallarta, Jalisco, México. Cedillo-Leal CN, Barrios-Quiroz G, Padilla-Paz S y González-Jauregui M (2023) Atención de interacciones negativas humano cocodrilo en zona urbana, Grupo SOS Cocodrilo Tampico. XV Congreso Internacional de Manejo de Fauna Silvestre de la Amazonía y Latinoamérica, Santa Martha, Colombia. Cedillo-Leal CN, Padilla -Paz SE y Barrios -Quiroz G (2024) Interacciones negativas humano-cocodrilo en el estado de Tamaulipas, México. VII Congreso sobre investigación y conservación de anfibios y reptiles, Puerto Escondido, México. García-Grajales J, and Buenrostro-Silva A (2018) Crocodile attacks in Oaxaca, Mexico: an update of its incidences and consequences for management and conservation. Acta Universitaria 28: 1-8. https://doi.org/10. 15174/AU.2018.1924 Khan W, Hore U, Mukherjee S and Mallapur G (2020) Human-crocodile conflict and attitude of local communities toward crocodile conservation in Bhitarkanika Wildlife Sanctuary, Odisha, India. Marine Policy 121: 104 -135. https://doi.org/10.1016/j.marpol.2020.104135 Langley RL (2010 ) Adverse encounters with alligators in the United States: an update. Wilderness and Environmental Medicine 21: 156 -163. https://doi.org/10.1016/J.WEM.2010.02.002 Rivera-Téllez E, López -Segurajáuregui G, Antaño -Díaz LA y Benítez -Díaz H (2017) Informe del Programa de Monitoreo del Cocodrilo de Pantano en México, temporadas 2014 a 2015 y análisis de tendencias del 2011 al 2015. Comisión Nacional para el Con ocimiento y Uso de la Biodiversidad. México 35pp . https://www.biodiversidad.gob.mx/media/1/planeta/cites/files/Informe%202011- 2015-v7.pdf Author-formatted, not peer-reviewed document posted on 25/11/2024. DOI:  https://doi.org/10.3897/arphapreprints.e142593 Non-fatal human crocodile interaction in Mexico 9 SEMARNAT (2018) Protocolo de Atención a Contingencias Humano -Crocodilianos. Componente de manejo de Poblaciones del Programa de Acción para la Conservación de Especies (PACE): Crocodylia ( Crocodylus acutus , Crocodylus moreletii, Caiman crocodilus chiapasiu s). SEMARNAT/CONANP, México. https://www.gob.mx/conanp/documentos/protocolo-de-atencion-a-contingencias- humano-cocodrilianos Villegas A y Reynos o VH (2013) Relative abundance and Habitat preference in isolated populations of Morelet’s crocodile ( Crocodylus moreletii ) along the coast of the Gulf of Mexico. Herpetological Conservation and Biology 8(3): 571−580. https://www.herpconbio.org/Volume_8/Issue_3/Villegas_Reynoso_2013.pdf Figure 1. Illustrates the location of Laguna del Carpintero in Tampico, Tamaulipas, Mexico. It indicates the site of the incident, the location of the victim's pre-hospital care, and the position of the crocodile nest. Existing infrastructure in the periphery of Laguna del Carpintero is also shown. Figure 2. A and B) Prehospital care of the person involved in the human-crocodile interaction (IH-C) Grade 4 non-fatal (NF) in the Laguna del Carpintero, Tampico, Tamaulipas; C) Spotting of the crocodile causing the IH-C NF in the pluvial channel; D) Spotting of the female protecting nest 42 m from the site of the IH-C NF. Figure 3. A) The crocodile responsible for the IH-C NF is held at the Tampico Fire Department facilities; B) Delivery to PROFEPA and C) transfer to final captive facility. Author-formatted, not peer-reviewed document posted on 25/11/2024. DOI:  https://doi.org/10.3897/arphapreprints.e142593