Cayo Miskito IMMA
Size in Square Kilometres
5 198 km2
Qualifying Species and Criteria
Guiana Dolphin – Sotalia guianensis
Criterion B (1)
Greater Caribbean Manatee – Trichechus manatus manatus
Criterion A; Criterion C (2)
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Summary
The Cayos Miskito IMMA is located along the northeastern Caribbean coast of Nicaragua. The area extends from Cabo Gracias a Dios on the northern boundary to the mouth of the Wauhta Lagoon on the southern boundary. It includes the coastal lagoons of Bismuna, Pahara and Wauhta and the adjacent marine waters up to 20 m isobath. The area is influenced by rivers, estuarine and marine waters. Seagrass and seaweed beds, as well as coral reefs, create the conditions for the development of numerous species of fish and invertebrates. The area is inhabited by a small population of Guiana dolphins (Sotalia guianensis) and the Greater Caribbean/Antillean manatee (Trichechus manatus manatus), with populations estimated to be 50 and 350 individuals, respectively. The Guiana dolphins in this IMMA represent one of only the two populations found in Central America (600 km south in Costa Rica and Panama). The area is inside the Cayos Miskitos EBSA, IBA and RAMSAR wetland status.
Description of Qualifying Criteria
Criterion A: Species or Population Vulnerability
The IMMA provides important habitat for greater Caribbean manatee (Trichechus manatus manatus) is listed Endangered on the IUCN Red List with a decreasing trend (Morales-Vela, et al., A. 2024). The estimated population in Nicaragua is around 350 individuals (Jimenez, 2001; Morales-Vela, B., Quintana-Rizzo, E. & Mignucci-Giannoni, A. 2024). The main threat in the area is illegal poaching by direct hunt by harpoon and gill or circle nets (Jimenez, 2002). A decrease in sightings or absence based on interviews and direct observations had been reported in areas suitable for your presence (Jimenez, 2002).
Criterion B: Distribution and Abundance
Sub-criterion B1: Small and Resident Populations
The Guiana dolphin (Sotalia guianensis) is a coastal species found in discrete and discontinuous populations from southern Brazil to Honduras (da Silva and Best, 1996; Secchi et al., 2018). This species is categorized as Near Threatened based on the IUCN Red List (Secchi et al., 2018). Although incomplete, assessments of its distribution, abundance, and threats are increasingly well-documented along the Atlantic coast of South America (Secchi et al., 2018). The northernmost populations are found in “Cayos Miskito y Franja Costera Inmediata Biological Reserve”, Nicaragua, and in “Gandoca-Manzanillo Wildlife Refuge”, Costa Rica, and Changuinola, Panama (Carr and Bonde 2000; Edwards and Schnell 2001; Acevedo et al., 2005; Gamboa and May-Collado, 2006; May-Collado et al., 2017).
This IMMA hosts one of the only two known small populations of Guiana dolphins in Central America. The other is on the border of Costa Rica and Panama, around 600 km to the south. Given the relatively small home ranges displayed by other populations of Guiana dolphins (e.g Oshima & de Oliveira, 2016, who describe small home ranges in Brazil), it can be expected that this population is resident in the IMMA with little or no exchange with other populations. Caballero et al. (2018) found one low- quality DNA sample from Cayos Miskito that shared one haplotype with samples from the Maracaibo Lake in Venezuela and the Colombian Caribbean. However, due to the geographic isolation of Cayos Miskito and the discontinuous distribution of Guiana dolphins along the coast of Central America, it is likely that this population is geographically isolated, including from populations in Costa Rica/Panama.
Edwards and Schnell (2001) conducted surveys from March through May of 1996-1998 in Cayos Miskito and reported that Guiana dolphins occur in shallow waters and within 300 m from shore. Depths of sightings ranged from 1 to 5 meters. During boat surveys 183 groups (536 individuals) were sighted (for areas with Sotalia, mean overall density = 0.604 individuals/km2, coastal areas = 0.647/km2, inlets = 0.578/km2, and lagoons = 0.486/km2). Overall, based on all sightings, mean group size was 3.01 (SD = 1.79, range 1–15) and varied among years (x̄= 4.20 in 1996, 2.58 in 1997, and 3.39 in 1998), but not for different months. Abundance was estimated to be 49 individuals based on the portions of the Reserve investigated (Edwards & Schnell 2001).
Sub-criterion B2: Aggregations
Boat-based surveys since 2007 revealed the Somers Isles to be a humpback whale (Megaptera novaeangliae) migratory stopover ground (Grove et al., 2023), with whales observed passing through Bermuda waters on their way south to the Caribbean breeding/calving grounds from mid-December into February as well as on their way north from the breeding/calving grounds to their northern feeding grounds March through to mid-May. Peak aggregations occur from mid-March to late April. An abundance survey indicated some 1,000-2,000 humpbacks migrate through Bermuda, with reconstructed abundances showing exponential growth since 2012 (Grove et al. 2022, 2023). Numerous important habitats have been identified including areas for feeding, resting, using sand holes to remove parasites, and singing (Stevenson and Werth, 2024). It is believed that the complex topography of the canyon enhances song transmission (Payne and Payne, 1985). On their way north, large numbers of humpbacks aggregate in the IMMA, with layovers up to 21 days. Groups with over a dozen individuals can be observed milling around for many hours. Their behaviour differs from earlier in the season when competitive groups are frequently observed. These large groups will then suddenly move at a consistent speed and heading (north) with coordinated breathing in what appears to be a convoy.
Criterion C: Key Life Cycle Activities
Sub-criterion C2: Feeding Areas
Through a series of extensive small boat and interview surveys Jimenez (2002) identified the coastal lagoons of Bismuna, Pahara and Wauhta, which are encompassed in this IMMA, as hosting some of the highest densities of Greater Caribbean manatees in Nicaragua. He reported that manatees living in these brackish lagoons feed on submerged grasses (Sirigodium filiforme and Thalassia testudinum) and mangrove (Rhizophora mangle) leaves.
Supporting Information
Acevedo-Gutiérrez, A., DiBerardinis, A., Larkin, S., Larkin, K., & Forestell, P. (2005). Social interactions between tucuxis and bottlenose dolphins in Gandoca-Manzanillo, Costa Rica. LAJAM 4, 49–54. https://doi.org/10.5597/lajam00069
Caballero, S., Hollatz, C., Rodríguez, S., Trujillo, F., Baker, C. S. (2018). Population structure of riverine and coastal dolphins Sotalia fluviatilis and Sotalia guianensis: patterns of nuclear and mitochondrial diversity and implications for conservation. Journal of Heredity: 757-770.
Carr, T., & Bonde, R. K. (2000). Tucuxi (Sotalia fluviatilis) occurs in Nicaragua, 800 Km North of its previously known range. Marine Mammal Science, 16(2), 447–452.doi:10.1111/j.1748-7692.2000.tb00936.x
Da Silva, V. M. F. & Best. R. C. (1996). Sotalia fluviatilis. Mammalian Species 527: 1-7.
Edwards, H. H. and Schnell, G. D. 2001. Status and ecology of Sotalia fluviatilis in the Cayos Miskito Reservce, Nicaragua. Marine Mammal Science 17(3): 445-472.
Gamboa-Poveda, M. (2009). Tamaño poblacional, distribución y uso de hábitat de dos especies simpátricas de delfines en el Refugio Nacional de Vida Silvestre Gandoca-Manzanillo, Costa Rica. Trabajo de graduación para optar por el grado de Maestría. Universidad Nacional, Costa Rica. 90p.
Gamboa-Poveda, M. & May–Collado L. (2006). Insights on the occurrence, residency, and behavior of two coastal dolphins from Gandoca-Manzanillo, Costa Rica: Sotalia guianensis and Tursiops truncatus (Family Delphinidae). Paper SC/58/SM4 presented to the IWC Scientific Committee, June 2006.
Guzman, H. M., & Condit, R. (2017). Abundance of manatees (Trichechus manatus) in a Panama wetland estimated from side-scan sonar. Wildlife Society Bulletin, 41(3), 556–565. https://doi.org/10.1002/wsb.793
Jiménez I. Heavy poaching in prime habitat: the conservation status of the West Indian manatee in Nicaragua. Oryx. 2002;36(3):272-278. doi:10.1017/S0030605302000492
May-Collado, L. J. (2010). Changes in whistle structure of two dolphin species during interspecific associations. Ethology. 116:1065-1074.
May-Collado, L.J. & D. Wartzok. 2009. A characterization of Guyana dolphin (Sotalia guianensis) whistles from Costa Rica: The importance of broadband recording systems. Journal of the Acoustical Society of America. 125 (2): 1202-1213.
May-Collado, LJ.; M. Amador-Caballero, J. J. Casas; M. P. Gamboa-Poveda; F. Garita-Alpízar; T. Gerrodette; R. González-Barrientos; G. Hernández-Mora; D. M. Palacios; J. D. Palacios-Alfaro; B. Pérez; K. Rasmussen; L. Trejos-Lasso & Rodríguez-Fonseca, J. (2017) Chapter 12. Ecology and Conservation of Cetaceans of Costa Rica and Panama. In Advances in Marine Vertebrate Research in Latin America (M. Rossi-Santos and C. Finkl eds). Springer Press. Print ISBN: 978-3-319-56984-0; Electronic ISBN: 978-3-319-56985-7
Mignucci-Giannoni, A. A., González-Socoloske, D., Aquarium, C., Aquino, J., Caicedo-Herrera, D., Castelblanco-Martínez, D. N., Claridge, D., Corona-Figueroa, F., Debrot, A. O., de Thoisy, B., Espinoza-Marín, C., Galves, J. A., García-Alfonso, E., Guzmán, H. M., Khan, J. A., Kiszka, J. J., de Oliveira Luna, F., Marmontel, M., Olivera-Gómez, L. D., … Silva, C. J. (2024). What’s in a Name? Standardization of Vernacular Names for Trichechus manatus. Caribbean Naturalist, 98, 1-17. https://www.eaglehill.us/CANAonline/CANA-access-pages/CANA-regular/CANA-098-Mignucci.shtml
Morales-Vela, B., Quintana-Rizzo, E. & Mignucci-Giannoni, A. 2024. Trichechus manatus ssp. manatus. The IUCN Red List of Threatened Species 2024: e.T22105A43793924. Accessed on 15 November 2024.
Oshima, J. M & Oliveira-Santos, M. C. (2016) Guiana dolphin home range analysis based on 11 years of photo-identification research in a tropical estuary. Journal of Mammalogy, Volume 97, Issue 2, 23 March 2016, Pages 599–610, https://doi.org/10.1093/jmammal/gyv207
Secchi, E., Santos, M.C. de O. & Reeves, R.(2018). Sotalia guianensis (errata version published in 2019). The IUCN Red List of Threatened Species 2018: e.T181359A144232542. https://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T181359A144232542.en. Accessed on 19 April 2024.
Secretariat of the Convention on Biological Diversity (2014). Ecologically or Biologically Significant Marine Areas (EBSAs): Special places in the world’s oceans. Volume 2: Wider Caribbean and Western Mid-Atlantic Region. 86 pages.
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