The Estero Real Delta is a Site of International Importance in the Western Hemispheric Shorebird Reserve Network (WHSRN) since 2016, following its nomination by the Nicaraguan Ministry of the Environment and Natural Resources (Ministerio del Ambiente y Recursos Naturales de Nicaragua) and local stakeholders. The Delta is situated in Nicaragua and forms part of the Gulf of Fonseca estuary system which is shared between El Salvador, Honduras and Nicaragua. The shorebird reserve area includes 7,650 hectares of intertidal mudflats, and these are feeding grounds for at least 10% of the biogeographical population of Wilson’s Plover (Charadrius wilsonia) and more than 1% of the population of other species such as Semipalmated Sandpiper (Calidris pusilla), Willet (Tringa semipalmata), Short-billed Dowitcher (Limnodromus griseus), Whimbrel (Numenius phaeopus), American Oystercatcher (Haematopus palliatus), and others.
The area is also a crossover site for species using the Pacific, Midcontinental and Atlantic Flyways. Map from: Morales S., Jarquín, O., Reyes, E. & Navedo. G. J. 2019. Shorebirds and Shrimp Farming: Assessment of Shrimp Farming activities on Shorebirds in Central America. Western Hermiphere Shorebird Reserve Network, Manomet, Massachusetts, USA
38 years ago the Estero Real Delta was declared a Nature Reserve that included great expanses of salt flats and winter lagoons. The high productivity of the wetlands, the hydrological dynamics they exhibit and the demand for shrimp for export resulted in this landscape being gradually transformed into shrimp farms. Currently 21,182 hectares are being used for shrimp aquaculture.
The effective conservation of the site requires understanding of the use of the intertidal and high tide wetlands, the daily and annual dynamics of the migratory and resident species, and the influences of the tides on the activities of the shrimp farms. Since 2012 the Quetzalli group, with the support of the Executive Office of the WHSRN and others, began counts of shorebirds and censuses of waterbirds in the area. Previously no such information existed to illustrate the importance of the Estero Real Delta for shorebirds. To date at least 30 of the 50 shorebird species known from Central America have been recorded here. There are also important concentrations of at least five species of shorebirds at the site. This includes sometimes over 30% of the biogeographic population of Wilson’s Plover and vast flocks of shorebirds in general numbering more than 40,000 individuals. In the remaining salt flats there are resident nesting populations of Wilson’s Plover and Black-necked Stilt (Himantopus mexicanus). During the southbound migration individuals of Red Knot (Calidris canutus) pass through that were banded on the East Coast of the USA, and there is also a wintering population of the American Oystercatcher that migrates from the East Coast.
Shorebirds at shrimp farm Acuicola Real at Delta del Estero Real. Photos: Salvadora Morales
Monitoring at the shrimp farms has demonstrated that the shorebirds use the recently harvested ponds and dikes for resting during high tide.During their migration these stopover sites are vital for their survival. In the breeding season, some birds use the shrimp farm dikes for nesting, as is the case for the Black Skimmer (Rynchops niger). Other dikes, where more than 20 years ago mangroves were planted, are now used as nesting colonies by waterbirds. In this way some shrimp farms are used as refuges for shorebirds (such as Acuícola Real), some are used as refuges for waterbirds (CAMPA) and others play both roles (Granjas Marinas in Honduras). The mudflats of the Estero Real Delta are used by shorebirds for feeding, the shrimp farms for resting and reproduction, and in summer, the natural salt flats, when they have not yet dried, are used for feeding, resting and reproduction. This is why WHSRN Executive Office is promoting the extension of the shorebird reserve in the Estero Real Delta, to include all habitat needs of the shorebirds.
The area has seen many advances and improvements in our knowledge of good practices and highlighted the importance of the site for shorebirds and waterbirds. A local and international team have worked together with shrimp farmers from the SEAJOY group, and other shrimp farms in México, Nicaragua, Honduras and Panama, to contribute to the identification of good aquaculture practices that promote the conservation of shorebirds. These practices need to be practiced by pilot programs to standardize their implementation. Currently the national system of protected areas of the Ministry of the Environment is updating the management plan that it first developed in 2006. The goal is to ensure that the good practices that have been identified will contribute to the management plan and other similar conservation strategies. This will allow their implementation to be promoted by updating standards, laws and decrees that are supported by the scientific data generated in recent years in the Gulf of Fonseca.
For more information on shrimp farming and shorebirds click here
Cover Photo: Waterfowl using a shrimp pound at WHSRN site Delta de Estero Real, Nicaragua. Photo: Salvadora Morales.
