CARMABI FOUNDATION
(ECOLOGICAL INSTITUTE)
To:
Milieudienst
Groot
Curaçao
While
the former seagrass and coral communities of the
Schottegat harbor have been almost totally degraded
by industrial contamination, the harbor remains a critical feeding area for
hundreds of shore and seabirds and contains high densities of baitfish yearround.
Consumption of baitfish by birds and larger predatory fish means that contaminants
enter the coral reef food web on a rather extensive scale and may pose an
environmental risk to the seabirds, sealife in general
and man as the top consumer of local seafood. Aside from degrading the environment
within the bay, studies show that contaminated waters flowing out of the Schottegat harbor cause environmental stress to most marine
life and degrade large tracts of the coral reef adjacent to the harbor. Due
to the area’s importance as feeding habitat for shore- and seabirds, and its
links to the coral reef food web, the level of environmental contamination
in the Schottegat should be reduced in the years to come. A baseline
study of natural resource values and contamination of the environment and
food web in the bay can be highly recommended.
High
densities of herons, egrets and other shorebirds such as sandpipers and plovers
can regularly be found feeding along shores of the bay. The bay is frequented
year-round by significant numbers of these animals. The mangroves bordering
the bay, especially on the western side are roosting sites of hundreds of
herons, cattle egrets, pigeons (ala blanka) and
doves (bula deifi).
The bay is an important feeding ground for seabirds such as
the Frigate bird (makuaku), gulls and the endangered
common tern. For instance, throughout the 2002 breeding season for common
terns in Curaçao, (April-July) a flock of about 150 adult common terns fed
in the bay (Motetbaai, Batipanabaai). This group of common terns, nesting at Janthiel bay and feeding in the Schottegat,
is the largest breeding colony of this species in the whole Caribbean Sea
(Buckley and Buckley, 2000; Debrot, in prep., Halewijn and Norton, 1984). By the end of August, about 100
mostly young birds continued feeding in the bay at Baaimacola. In June and July 1996, on one day (26 July)
16 Frigate birds were counted (A. Debrot, pers. obs.) feeding in the western
side of the Schottegat (APNA) togethern with upwards of 50 common terns. These animals were also seen in large numbers
in the Batipanabaai and the waters east of Curaçao
Dock Maatschappij. On an annual basis the bay is
visited by 5-10 Osprey which spend several months feeding there (also at the
Amstel Brewery).
Use
of the bay by these large numbers of seabirds and wading birds is due to the
high densities of small baitfish. Massive fish kills due to the contaminated
waters (also high temperature, high BOD and localized low oxygen) and poor
circulation are almost an annual occurrence.
People
fish in the bay on a daily basis. All day long people can be seen fishing
along the St. Annabaai. Several times a week people
can be seen fishing at the culvert along the Nieuwehavenweg. This location is generally fished by people
of oriental nationality and the fish probably end up being served to clients
in oriental restaurants. Large Tarpons (Sabalo),
Ladyfish (Makambi) and Snook (Sapati
Solda) are tolerant of poor water quality and are
abundant in the Schottegat harbor. These are valuable
sport fish and are fished frequently by recreational sport fishers in the
western side of the bay. Articles on this topic have appeared recently in
the Dutch sportsfishing magazine “Beet”. The fish
from the bay often smell and tast of petroleum.
Consumption is likely unhealthy. The bay contains large numbers of commercially
valuable blueshelled crab (Calinectes
spp.) (Huyghe, 1984) and spiny lobsters (Panilurus
argus) (Jalink and
Donkersloot, 1985).
The fishlife inside the bay is connected to the food web of the coral reef due to consumption of baitfish and lifecycle migration of many species. Contaminants in the food web likely get concentrated and spread throughout the reef ecosystem of the island where fishing effort by artesanal fishermen is very high.
Curaçao has nine native freshwater shrimp species and eleven native freshwater fishes. All these species spend part of their life in estuarine areas and the sea. The Schottegat is the largest freshwater drainage basin of the island and is of importance to the freshwater fauna of several streams which drain into the Schottegat (eg. Muizenberg-Rio Canario) (Debrot in press, Debrot, subm.). The freshwater shrimps originating from the Schottegat are caught and consumed by island inhabitants during the rainy season.
The contaminated waters which flow out of the Schottegat harbor significantly stress and degrade coastal coral reef communities in the vicinity Willemstad (e.g. Gast, 1998; Gast et al., 1999) These stressed coral communities further serve as source of infectious coral reef diseases which may then spread to large tracts of the reef (Bak et al, 1984; Nagelkerken et al., 1999).
Bak, R. P. M., M. J. E. Carpay and E. D. de Ruyter van Steveninck. 1984. Densities of the sea urchin Diadema antillarum
before and after mass mortalities on the coral reefs of Curacao. Mar. Ecol.
Progr. Ser. 17: 105-108.
Buckley, P. A. and F. G. Buckley. 2000.
Breeding common terns in the Greater West Indies: status and conservation
priorities. Pp. 96-102. In: E. A. Schreiber and D.S. Lee (eds.) Status and
conservation of West Indian seabirds. Soc. Caribb.
Ornith., Spec. Publ. No. 1. 225
pp.
Debrot, A. O. Tern breeding in Curaçao and
Bonaire, 2002, and conservation recommendations (in prep.)
Debrot, A. O. The freshwater
shrimps of Curaçao, West Indies (Decapoda, Caridea).
(in press., Crustaceana)
Debrot, A. O. A survey and review of the freshwater fishes
of Curaçao, West Indies. (subm. Car. J. Sci.)
Gast, G. J. 1998. Microbial densities and dynamics in fringing coral reef waters. Doctoral Dissertation, University of Groningen, The Netherlands, 123 pp.
Gast, G. J., P. J. Jonkers, F. C. van Duyl and R. P. M. Bak. 1999. Bacteria, flagellates and nutrients in island fringing reef waters: influence of the ocean, the reef and eutrophication. Bull. Mar. Sci. 65:523-538.
Halewijn, R. Van, and R. L. Norton. 1984. The status and conservation of seabirds in the Caribbean. Pp. 169-222 in J. P. Croxall, P. G. H. Evans and R. W. Schreiber (eds.) Status and conservation of the World’s Seabirds. ICBP Tech. Publ. 2, ICBP, Cambridge, England. 778 pp.
Huyghe, M. 1984. Verspreiding en grootte van Callinectes spp. Op Curacao. Carmabi Report, Curacao. 48 pp.
Jalink, C. And C. Donkersloot. 1985. Onderzoek naar de verspreiding van Panulirus argus aan de zuidkust van Curacao. Carmabi report, Curacao. 74 pp.
Nagelkerken I, Smith G.W., Snelders, E., Karel M, & James, S. 1999. Sea urchin (Meoma ventricosa) die-off in Curaçao (Netherlands Antilles) associated with a pathogenic bacterium. Dis. Aquat. Org. 38:71-74.
Sincerely,
Dr. W. L. Bakhuis, director
cc.
Refineria Isla
J. Hasselmeyer, director
R. Ruggenaath, environmental officer
Refineria di Kòrsou
H. Parisius, director
Carmabi
L. Pors, manager Curaçao Underwater Park