Habitat use by the Antillean manatee (Trichechus manatus) during an extreme dry season in an urban lake in Tabasco, Mexico

Abstract

There are three important manatee areas in Mexico: the coasts of the State of Quintana Roo; the freshwater systems within the lower basin of the Grijalva-Usumacinta rivers, which host the largest manatee population; and the rivers of central and southern Veracruz. The Antillean manatee (Trichechus manatus manatus) is a threatened species throughout its range. In the Grijalva-Usumacinta region, two of the current threats to manatees are the effects of extremely dry periods and geographical isolation. The objective of the study was to evaluate the behavior and habitat use of the landlocked manatee population inhabiting Laguna de las Ilusiones, Villahermosa, Tabasco, under fortuitous dry conditions, to conduct an evaluation and implement a monitoring plan for landlocked manatees. In this work, we gathered information on the differential use of the lake, and on whether this use is related to the known habitat characteristics that govern the distribution of manatees. Using VHF tags, we followed the activities of four manatees (three females and one male) to characterize and quantify four behaviors, namely feeding, resting, exploring, and traveling, between April and August 2007. We built Kernel polygons for the 25, 50, 75, and 95 % of the utilization distribution (UD). We modeled the habitat using a binary logistic regression and explored the association between the tagged manatees using Cole's simple coefficient of association. Manatees were concentrated mainly to the northeast of the lake. The best feeding logistic model included depth, distance to the the shore, tree cover, and wind speed (Table 1), and yielded differences between periods (H = 9.85, P = 0.007, Figure 5). The logistic models fit poorly for resting, exploring, and traveling (Table 1). The resting model included distance to the the shore, tree cover, and company, and yielded differences between periods (H = 6.68, P = 0.035). Traveling included depth, cloud cover, and human activities, and yielded differences between periods (H = 7.55, P = 0.023). Exploration included depth and company, and did not differ between periods (H = 1.55, P = 0.461). We had the opportunity to assess these behaviors under dry conditions, and our findings are not necessarily applicable to the rainy season. The northern portion of the lake is an embayment connected to the central zone by a 50 m-wide shallow channel, which limited the movement of manatees. Higher food availability and stress avoidance might make manatees choose this area. Feeding was better modeled by the habitat characteristics included in the study. Feeding increased slightly in the evenings. Exploring and traveling were the behavior types observed most frequently in manatees; maybe they were moving across food patches or known areas. Manatee social encounters are reported as short-term and sporadic, but in this study manatees were observed in groups during nearly half of the observation time. When the availability of grasses and aquatic plants is low, manatees increase their consumption of other food items li...

Behaviour and occurrence of the Antillean manatee (Trichechus manatus manatus) in relation to habitat characteristics and the influence of human activities in a protected area in north‐eastern Brazil

“…The manatees at the study site spent most of their time feeding on the bottom (BF), with SM, followed by RD. Similar behaviours have been recorded in other areas with similar environmental characteristics (Araújo & Marcondes, 2003; Castelblanco‐Martínez et al, 2009; Pablo‐Rodríguez & Olivera‐Gómez, 2012; Pablo‐Rodríguez et al, 2016; Ramírez‐Jiménez et al, 2017). The SM is associated with exploring the environment in search of food (Bailey et al, 1996).…”

“…The behavioural ecology of free‐ranging T. manatus was first studied in the 1970s in Florida, focusing on the Florida manatee subspecies, T. m. latirostris (Hartman, 1979). Behavioural research of Antillean subspecies ( T. m. manatus ) has focused on populations in the Caribbean and Central America (Castelblanco‐Martínez et al, 2013; Alvarez‐Alemán et al, 2017; Ramírez‐Jiménez et al, 2017), and there are a few behavioural studies in the wild in Brazil (Paludo & Langguth, 2002; Alves, 2003; Silva et al, 2011).…”

Accomplishments and challenges of the research on Antillean manatee: A bibliometric analysis

“…Another relevant category is 'Conservation' (16.6%), which includes quantitative or qualitative descriptions of threats to manatee viability/health such as boat collisions (e.g., Borges et al, 2007), poaching (e.g., Jiménez-Pérez, 2002), contaminants (e.g., Anzolin et al, 2012; Romero-Calderón et 1980-1982 1983-1987 1988-1992 1993-1997 1998-2002 2003-2007 2008 1980-1982 1983-1987 1988-1992 1993-1997 1998-2002 2003-2007 2008 (e.g., Vanoye, 2002;Silva et al, 2009;Takeuchi et al, 2016). In the topic behavior (10.3%), papers approaching aspects on manatee communication (e.g., Alicca et al, 1997;Sousa-Lima et al, 2008;Umeed et al, 2018;Merchan et al, 2019;Ramos et al, 2020), learning and welfare (e.g., Hénaut et al, 2020), husbandry (Lima et al, 2005), circadian rhythm (Holguin-Medina et al, 2015), habitat preferences (e.g., Ramírez-Jiménez et al, 2017), and movements and migrations (e.g., Castelblanco-Martínez et al, 2013) were found.…”

Seeing in the dark: A review of the use of side-scan sonar to detect and study manatees, with an emphasis on Latin America

“…Not surprisingly, the majority of the work has occurred in Mexico, because that is where the technique was first described and had the best results in the initial study (Gonzalez-Socoloske et al, 2009). However, it was surprising to see the number of unique locations (at least seven, including Catazajá wetlands in Chiapas, Alvarado Lagoon System in Veracruz, Laguna de las llusiones, Pantanos de Centla, and San Pedro River in Tabasco, Laguna de Terminos in Campeche, and Rio Hondo in Quintana Roo) and independent research groups (at least seven) within Mexico that are using the methodology (Rodas-Trejo et al, 2008;Gonzalez-Socoloske et al, 2009;Daniel-Rentería et al, 2012;Gonzalez-Socoloske & Olivera-Gomez, 2012;Acevedo-Olvera et al, 2015;Puc-Carrasco et al, 2016;Puc-Carrasco et al, 2017;Ramírez-Jiménez et al, 2017;Serrano et al, 2017;Ladrón de Guevara-Porras et al, 2019;Corona-Figueroa et al, 2021, 2022. The 15 countries with confirmed use of side-scan sonar are likely an underrepresentation of the overall number because there are some localities where it has been used, but they are yet to publish their results in any format that we were able to assess.…”

“…In addition, many studies have indicated that in seasonally flooding systems (e.g. Alvarado Lagoon System, Usumacinta-Grijalva Basin, Orinoco Basin, Sanaga River Basin, Amazon River Basin), the dry season provides the best opportunities to use the technology due to the concentration of the manatees and the shallow water (Arévalo-González et al, 2014;Ramírez-Jiménez et al, 2017).…”