Saba Bank National Park

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Chapter 4. ECOLOGICAL CRITERIA

(Guidelines and Criteria Section B/ Ecological Criteria) Nominated areas must conform to at least one of the eight ecological criteria. Describe how the nominated site satisfies one or more of the following criteria. (Attach in Annex any relevant supporting documents.)

Representativeness:


Coral reefs:

Saba Bank meets the true definition of a seamount being isolated by deep water; in this case the nearest islands are Saba and St. Eustatius. Except for the fact that it does not break the water surface, Saba Bank is a classic atoll consisting of a submerged mountain crowned at the summit with a ring of actively growing coral reefs.The Saba Bank is considered to be a submerged coral atoll. A substantial eastern part (225 km2) is between 10 and 20 m depth consists of extensive coral reefs froming a fringe along the edge of the bank of 55 km.

Macro-algal communities:

The relatively unstructured interior plains of the Bank consist of hard substrate, bare or with a thin layer of sediment, covered with macro-algae and scattTeh coral reefs of the Sabered sponges and gorgonians. In depths of 25-30 m, the average depth of the Bank, particularly robust specimens of algae typical of shallower seagrass beds were found, but here in the total absence of any seagrasses (seagrasses generally do not grow below 20 m). Few filamentous and thin sheet forms indicative of stressed or physically disturbed environments were observed.

Littler et al states that "the two most diverse areas for algae reported in the Caribbean had been Diamond Rock, Martinique, and Pelican Cays, Belize, a mangrove, seagrass, and coral complHabitats on Saba Bank have far exceeded both of these places for species diversity per unit collection effort. A major reason for this uniqueness and richness is the sheer size and habitat range of the seamount/atoll."

Conch and lobster populations

The Saba bank provides important habitat for Caribbean spiny lobster (Panulirus argus) and Queen Conch (Strombus gigas)

Foraging area for sea turtles

As are other shallow areas in the Caribbean, the Saba Bank is presumed to be an important foraging area for sea turtles, rich as it is in sponges.

Humpback whale calving area

Like the Silver Banks near the Dominican Republic and other shallow banks in the Caribbean, the Saba Bank is likely an important area for humpback whales, that are sighted regularly or heard singing in groups during the last survey on the Bank, and the area may be a calving ground for the humpbacks.

 

 

 

 

 

 

 

 

 

Conservation value:


The  Saba Bank National Park contains the whole of the Saba Bank and is large enough to be a self contained system for the ecosystems present within the National Park. There are indications that some of the new (sub)species of fish discovered on the Saba Bank may be endemic to the area.

In addition the Saba Bank National Park is:

  • A source of recruitment for corals, fish, lobster and other species for the surrounding region.
  • Important for endangered sea turtles as a foraging area for adults.
  • Important for humpback whales as resting place in the winter months, and possibly as a calving area.
  • A center of macro-algal diversity
  • an important area for Queen Conch

Rarity:


The Saba Bank has been identified as having the greatest diversity of marine macro-algae of the Caribbean

A new gobioid fish species of the genus Starksia (Starksia williamsi) was discovered on the Saba Bank, other species of Starksia found on the Saba Bank had different genetic lineages than elsewhere in the region (Baldwin et al, 2011). A new species of gorgonian (Pterogorgia n.sp.) was discovered on the Saba Bank in shallow water. Since the shallow water gorgonian fauna in the Caribbean is quite well known and the new species was quite distinct from the other three species in the genus, this discovery was quite surprising. These findings may indicate that the Saba Bank may have its own endemic species, occurring only on the Saba  Bank.

Etnoyer et al (2010) found that the gorgonian diversity of the Saba Bank was higher than in other areas in the Caribbean (Florida, Providencia Island Colombia, and Puerto Rico). The species accrual curve of the Saba Bank indicates that not even all the common species, let alone rare species, have been found, so the actual diversity will be even higher.

 

Naturalness:


The Saba Bank is a seamount separated from land by deep water. Human impact has only been from fisheries, so the area has been relatively free of disturbance by human influence. The coral reefs of Saba Bank are far removed from landbased sources of pollution or nutirents. since 1996 fisheries has been regulated and restricted to about 10 fishing permits for small (35-50 ft) fishing boats using only lines and traps

Although there has been a clear impact from fisheries, the area can still be considered quite natural, especailly compared with most other areas directly offshore of human populations.

Critical habitats:


As stated above the Saba Bank is a foraging area for endangered sea turtles (annex 2) and important for their survival.

Similarly it is presumed to be an important resting or possibly calving area for humpback whales (annex 2).

The Saba bank contains extensive coral reefs (annex 3) not only in need of protetion themselves, but providing critical habitat for endangered or vulnerable fish species such as several grouper species, and Balistes vetula, the Queen triggerfish.

The area also contains spawning aggregation areas for Balistes vetula (vulnerable) and other species such as Epinephelus guttatus (Red Hind)

The area contains Queen conch (Strombus gigas) populations (annex 3) that were severely overfished and are now recovering.

Diversity:


Because the Saba Bank National Park encloses the entire seamount with an area of over 2000 km2 and has been shown to have a unique diversity it is clear that it contains sufficient diversity for its long term viability

Connectivity/coherence:


Saba Bank may be considered an important Caribbean reef habitat because it has a large extent, and it is positioned in an upstream position relative to neighboring Puerto Rico (to the northwest) and the Meso-American Barrier Reef (to the far west), in relation to the direction of flow for the Caribbean current. The Caribbean current flows east to west along the southern parts of the Antilles Ridge, turning to the northwest at higher latitudes. Long-lived invertebrate larvae (e.g. spiny lobster Panulirus argus, Queen conch Strombus gigas) could theoretically disperse from Saba Bank to downstream habitats.

As an important area for humpback whales Saba Bank is linked to other resting places of humpback whales in the Caribbean such as the Silver Banks area and the summer grou ds of the humpback whales in the Northern Atlantic.

As a foraging area for adult sea turtles it is clearly linked to the nesting beaches of these sea turtles, which have as yet not been identified.