true

ISRA FACTSHEETS

SOUTH AMERICAN ATLANTIC REGION

ISRA FACTSHEETS

SOUTH AMERICAN ATLANTIC REGION

Juan Griego ISRA

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Juan Griego ISRA

Juan Griego

Summary

Juan Griego is located off northern Margarita Island in Venezuela. The area includes coastal waters, and the habitat is characterised by a mix of hard substrates and soft sediments. It is influenced by seasonal upwelling, driven by the Caribbean Current and trade winds. Within the area there are: threatened species (e.g., Smalleye Smoothhound Mustelus higmani); range-restricted species (Venezuelan Dwarf Smoothhound Mustelus minicanis); and reproductive areas (Smalleye Smoothhound).

Juan Griego

Juan Griego

DESCRIPTION OF HABITAT

Juan Griego is located in the northern region of Margarita Island in Venezuela. This coastal area extends from Manzanillo at the northeastern tip of the island to La Guardia Cove in the centre. It features rugged coastal landscapes, including rocky shores, sandy beaches, and cliffs. The seafloor consists of a mix of hard substrates and soft sediments, particularly sand, silt, and clay (Torres Hugues & Córdova López 2013). The shallow coastal waters transition to deeper zones, providing a gradient of ecological niches. This area is influenced by upwelling systems driven by the westward Caribbean Current and the trade winds, enhancing biological productivity (Rueda-Roa & Muller-Karger 2013). The principal upwelling season is from December–April, with a secondary season from June–August (Rueda-Roa & Muller-Karger 2013).

This Important Shark and Ray Area is benthic and pelagic and is delineated from surface waters (0 m) to 30 m based on the bathymetry of the area.

CRITERION A

VULNERABILITY

Two Qualifying Species considered threatened with extinction according to the IUCN Red List of Threatened Species regularly occur in the area. These are the Endangered Smalleye Smoothhound (Pollom et al. 2020a) and Venezuelan Dwarf Smoothhound (Pollom et al. 2020b).

CRITERION B

RANGE RESTRICTED

This area holds the regular presence of the Venezuelan Dwarf Smoothhound as a resident range-restricted species. Venezuelan Dwarf Smoothhounds have been observed in this area, primarily as incidental catch in the trawling shrimp fishery operating in La Guardia Bay in 3–4 m depth (Rodríguez et al. 2024). A total of 20 landing site visits were conducted in the area from February to April 2024, with Venezuelan Dwarf Smoothounds recorded in eight of these visits. This species comprised 41% of the shark and ray bycatch in this fishery, which operates in La Guardia Cove, in the southwest of the area. Sizes of animals ranged from 27–31 cm total length (TL). The size-at-birth for Venezuelan Dwarf Smoothhounds ranges from 22.4–29.5 cm TL (Tagliafico et al. 2015), indicating that captured individuals were neonates. One individual with an open umbilical scar was recorded (Rodríguez et al. 2024). Additionally, fishers indicated that they commonly release pups, so the landed catch may be an underestimate (P Rodríguez pers. obs. 2025). Large females were also reported on one occasion (P Rodríguez pers. obs. 2025), highlighting the importance of this area for the species. Although it appears likely that this area is important for the reproduction of the species, additional data from other years are needed to confirm this. The species only occurs in the North Brazil Shelf and the Caribbean Sea Large Marine Ecosystems (LME) (Pollom et al. 2020b).

While this species was historically reported from the northern region of Margarita Island, outside of the area (Tagliafico et al. 2017), more recent landing site investigations in the Margarita Island region conducted between 2014–2024 did not record the species outside of this area (LA Zambrano unpubl. data 2025). This further supports the importance of the area for this range-restricted species.

CRITERION C

SUB-CRITERION C1 – REPRODUCTIVE AREAS

Juan Griego is an important reproductive area for one shark species.

Fisheries landing surveys show that Smalleye Smoothhounds are regularly captured in this area throughout the year (Tagliafico et al. 2015; Macías-Cuyare et al. 2020). Between 2015–2016, 28 landing site surveys were undertaken at Juan Griego port, in this area, with visits in September–November 2015 (n = 7), February 2016 (n = 7), July 2016 (n = 6), September (n = 7), and November 2016 (n = 2) (Macías-Cuyare et al. 2020). Various fishing gears were used to capture sharks, including mainly longlines, bottom-set gillnets, and driftnets. Fisher interviews confirmed capture of the species within this area (M Macias pers. obs. 2025). A subsample of 313 Smalleye Smoothhounds were measured, and more than half of all females (55%) were pregnant. Neonates with a size of <26 cm TL comprised 13% of the total samples (Macías-Cuyare et al. 2020). The size-at-birth for the species is 23–26 cm TL (Macías-Cuyare et al. 2020). Although the species is captured throughout the broader region, survey results indicate that the area is particularly important for the gestation of females, potentially for pupping, and for the early life stages of Smalleye Smoothhounds. By contrast, a total of 2,223 individuals were measured during weekly surveys of two bottom-set gillnet landing sites and two fish markets from January 2006 to December 2008 (Tagliafico et al. 2015). Only one of these four sites is within the area, while the others are in northwestern and southeastern Margarita Island. The overall sex ratio was close to even (1.1:1 female:male), and their size ranged between 20.0–88.4 cm TL. Of the 1,156 females assessed, ~16% were pregnant and ~6% had recently given birth. Pregnant females were observed throughout the year, indicating continuous reproduction. Neonates <30 cm TL were also captured (Tagliafico et al. 2015). Another study recording 784 Smalleye Smoothhounds captured in commercial fisheries and landed in Cumaná (~70 km straight-line distance from Juan Griego) reported mostly males with a sex ratio of 0.2:1 female:male (Marquez et al. 2019). These comparisons highlight the regional importance of Juan Griego for the reproduction of Smalleye Smoothhounds.

Juan Griego

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