http://www.researchgate.net/profile/Nemer-Narchi/publication/370497014_Towards_reef_restoration_in_Zihuatanejo_Guerrero_Mexico_lessons_learned/links/645549224af78873525eb634/Towards-reef-restoration-in-Zihuatanejo-Guerrero-Mexico-lessons-learned.pdf

https://revistas.ucr.ac.cr/index.php/rbt/article/view/54792

ABSTRACT

Coral Reef Structures in Zihuatanejo, Guerrero are well-preserved. The coverage of living corals, near 60 % at several locations, makes them comparable to other coral reefs in the states of Oaxaca, Jalisco, and Nayarit and with high potential to promote their conservation. Objective: To present the outcome of 12 years of research in coral communities from Zihuatanejo, Guerrero, as a justifying argument for the current conservation efforts in the area. Methods: We developed a baseline on the conservation status of the reef structures, bioerosion processes and the source of major natural and anthropogenic impacts. We assessed the genetic diversity of the coral zooxanthellae symbionts, the outcome of a technique of coral transplantation to recover the coverage of living corals and the local ecological knowledge to involve local inhabitants to promote conservation. Results: At least five coral reefs remain exposed to a medium-low level of impact by bioerosion and anthropization. Coral transplantation experiments made in the area showed records of transplant survival nearing 90 %. Although the warming of the sea surface temperature that occurred during the El Niño of 2015-2016 caused coral bleaching and mortality in several coral populations in this area, there were no affectations attributed to this phenomenon in other locations. This response was not related to the level of exposure to anthropogenic impacts, and the presence of thermal resistant zooxanthellae was assessed using molecular tools, confirming the existence of zooxanthellae of the genus Durusdinium. The analysis of local ecological knowledge of the inhabitants of Zihuatanejo showed that they keep elaborate knowledge on the ecology of coral reefs. This is complemented with scientific knowledge that will encourage community participation in conservation strategies. https://doi.org/10.15517/rev.biol.trop..v71iS1.54792 SUPPLEMENT 2 Revista de Biología Tropical, ISSN: 2215-2075 Vol. 71 (S1): e54792, abril 2023 (Publicado Abr. 30, 2023) INTRODUCTION The eastern tropical Pacific has suboptimal oceanographic conditions for coral community development (Glynn & Ault, 2000). The Mexican Pacific coast is a region with high primary productivity enhanced by the nutrient enrichment coming from riverine discharge, upwelling currents, and a high seasonal temperature variability jointed with high turbidity of the water column that difficult coral survival (Reyes-Bonilla, 2003). The development of human settlements near coral communities also has exerted negative impact through the discharge of sewage, solid waste, and land transformation, causing coastal erosion and enhancing the sedimentation rate at some sites harboring corals (Nava & Ramírez-Herrera, 2012). Added to these anthropized conditions is the impact of the El Niño phenomenon, which in the last decades has decimated entire populations of reef corals at some localities in this region (Nava et al., 2019). Some of these impacts, chronic and silent, exceptional or devastating, have occurred without being recorded in detail. This is not the case with the coral communities from Zihuatanejo, which remain among the most conserved on the Mexican Conclusions: A long-term multidisciplinary strategy is required for coral reef conservation that encompasses: 1) assessing the role of the overall holobiont in the thermal resistance of corals from this area and 2) establishing restoration strategies of coral reefs that include the local knowledge about marine ecology, for the establishment of coral reef protection and management schemes put in place by local inhabitants. Key words: Pocillopora; restoration; Mexican Pacific; citizen science; coral reefs.

INTRODUCTION

The eastern tropical Pacific has suboptimal oceanographic conditions for coral community development (Glynn & Ault, 2000). The Mexican Pacific coast is a region with high primary productivity enhanced by the nutrient enrichment coming from riverine discharge, upwelling currents, and a high seasonal temperature variability jointed with high turbidity of the water column that difficult coral survival (Reyes-Bonilla, 2003). The development of human settlements near coral communities also has exerted negative impact through the discharge of sewage, solid waste, and land transformation, causing coastal erosion and enhancing the sedimentation rate at some sites harboring corals (Nava & Ramírez-Herrera, 2012). Added to these anthropized conditions is the impact of the El Niño phenomenon, which in the last decades has decimated entire populations of reef corals at some localities in this region (Nava et al., 2019). Some of these impacts, chronic and silent, exceptional or devastating, have occurred without being recorded in detail. This is not the case with the coral communities from Zihuatanejo, which remain among the most conserved on the Mexican central Pacific coast. These communities vary in their extension and structural characteristics, but all have provided relevant life support systems to the inhabitants of the municipality of Zihuatanejo de Azueta for 400 years (SánchezBriones, 2010). Since that time, the activity of traditional fishing has been part of the identity of the inhabitants of this municipality and the region (Reyes-García, 2012). Since the decade of 1980, Playa las Gatas has been an important tourist destination in Zihuatanejo, allowing the establishment of several service providers offering lodging, food, and recreational services. The first studies of the conservation state of five locations with coral communities in the area began in 2009, which are Islote Zacatoso, Playa las Gatas, Caleta de Chon, Playa Manzanillo, and Playa Riscalillo (Fig. 1). Such studies provided relevant information about the environmental conditions of each site, suggesting that these communities are under pressure of anthropogenic origin (Nava & Ramírez-Herrera, 2012). Data on the coverage of living corals and their ratio concerning dead coral substrata have evidenced the presence of locations with reef patches with an acceptable conservation status (Nava & Ramírez-Herrera, 2012; Nava et al., 2019; Nava et al., 2021). These data suggest such communities present a high potential to develop restoration initiatives. Assuming the process of sponge bioerosion as an indicator of the conservation state of the reef ecosystem, the survey of boring sponge abundance in reefs from Zihuatanejo revealed that bioerosion may weaken the reef framework in locations with high cover of dead corals (Nava et al., 2019). Previous tests of a reliable and low-cost strategy for coral transplantation on rocky substrata showed to be effective and that it can be used by local inhabitants at sites with reduced coral coverage. Nonetheless, the impact of the event of the El Niño of 2015-16 showed that it is necessary to implement a multidisciplinary strategy to restore the coverage with living corals resistant to thermal stress (Cárdenas-Alvarado et al., 2021). The algal symbionts of corals (Symbiodiniaceae) are relevant since they provide corals with nutrients and oxygen and allow them to increase their calcification rate (Muller-Parker et al., 2015). Since Cladocopium and Durusdinium are the most tolerant genera to high seawater temperatures (Baker et al., 2004; LaJeunesse et al., 2018), we aimed to test if the identity of algal symbionts may influence the response of coral bleaching in Zihuatanejo and now are attempting restoration emerging from a citizen science approach. Recent research has demonstrated that local inhabitants are owners of their elaborated ecological knowledge that is used to manage natural resources from coral communities (Drouet-Cruz, 2020). Current efforts aim at integrating all available information to sustain strategic alliances among academic, citizen, and government agencies to develop restoration initiatives based on the participation of local inhabitants that promote coral communities restoration with thermally resistant reef corals. This contribution provides an analysis of the outcome of this work in process and proposes an approach to establish a long-term initiative for the conservation of coral communities from Zihuatanejo, Guerrero.