Biodiversity of the Caribbean A Learning Resource Prepared For: (Protecting the Eastern Caribbean Region’s Biodiversity Project) Photo supplied by: : Rick Searle (EKOS Communications, Inc.) Part 2 / Section A Open Ocean Ecosystems February 2009 Prepared by Ekos Communications, Inc. Victoria, British Columbia, Canada [Part 2/Section A] Open Ocean Ecosystems Table of Contents A.1. What is the Ocean? A.2. Ocean Zones A.3. Influences on the Ocean A.4. Oceanic Species A.5. Emerging Trends/Major Threats A.5.a. Overexploitation A.5.b. Habitat Destruction A.5.c. Pollution A.5.d. Climate Change A.6. Conserving Ocean Ecosystems A.7. Case Study: Folkestone Park and Marine Reserve (FPMR), Barbados A.8. Activity 1: Coastal Activities A.9. Activity 2: Caribbean Fish Who’s Who? A.10. References [Part 2/Section A] Open Ocean Ecosystems A.1. What is the Ocean? An ocean ecosystem is a body of salt water where currents, waves, and tides intermingle to create a distinct community of organisms that interact together in the physical environment. Ocean ecosystems are home to some of the most diverse life on Earth and hold a varied number of plants, animals, and microor- ganisms1. Due to the size and complexity of ocean ecosystems, many of their species are still unknown to scientists. With their rich biodiversity, ocean ecosystems are essential to the economic, social, and cultural life of those countries interspersed among them. Ocean or marine ecosystems are different from terrestrial ecosystems in the great extent and rate of dispersal of nutrients, materials,and holoplanktonic, organisms that live their entire life in the sea, floating in the water between the bottom and surface. Marine ecosystems tend to be more open than their terrestrial counterparts, in that they exhibit higher rates of movement in and out of areas as a result of the forces of ocean waves and currents2. Ocean ecosystems differ in size, form, and species diversity depending on their location around the globe. Oceans, however, are important for all humans as they are key influences on climate and weather and produce extensive food for human consumption. Caribbean Sea Large Marine Ecosystem NOAA Fisheries: Northeast Fisheries Science Center. (2003) Large Marine Ecosystems: The Caribbean Sea, an arm of the Atlantic Ocean, is a partially Caribbean Sea. Retrieved from: na.nefsc.noaa.gov/lme/text/lme12.htm enclosed sea in the Western Hemisphere bounded by North, South, and Central America. The Caribbean encompasses an area 3 A.2. Ocean Zones of 3,274,085 square kilometers . The average depth of this sea is The Caribbean Sea, like all oceans, is divided into five zones 2200 metres, with the Cayman Trench at 7535 metres being the based on water depth and light penetration. greatest depth measured to this date. It is estimated that 40% of the Caribbean’s human population lives within two kilometers 4 1. The epipelagic, or sunlit zone, is the top layer of the ocean of the coast . The ocean ecosystem is an essential factor in the where enough sunlight penetrates for plants to carry out social, cultural, economic, and political lives of all Caribbean photosynthesis. people. 2. The mesopelagic, or twilight zone, is a dimly-lit zone where some light penetrates, but not enough for plants to grow. 3. The bathypelagic, or midnight zone, is the deep ocean layer where no light penetrates. 4. The abyssal zone is the pitch-black bottom layer of the ocean where pressure is immense and water temperature is almost freezing. 5. The hadal zone is the water found in the ocean’s deepest trenches. While plants only exist in the sunlit zone (approximately five percent of the ocean) where photosynthesis can occur, animals and microorganisms are found at all depths of the ocean, though their numbers are greater near the surface where food is readily available. Over 90% of all species dwell on the ocean bottom, however, and one rock can provide habitat to over ten major groups such as corals, molluscs and sponge5. Oceanic species can either be pelagic or benthic. Pelagic species live in the open sea, away from the sea bottom, whereas benthic species live on the bottom of the ocean. Photo supplied by: Ministry of Agriculture, Lands, Forestry and Fisheries (St. Lucia) [Part 2/Section A] Open Ocean Ecosystems Ocean Zones the sea in the southeast and flow in a northwest direction. These currents are created by the sun warming the ocean water at the sunlit zone equator. 0-200 metres twilight zone Because of these currents and the Caribbean’s proximity to the equator, the water temperature here ranges from 25.5 degrees 1000 metres Celsius in the winter to 28 degrees Celsius in the summer6. midnight zone The Caribbean Sea is a central area for many of the hurricanes that occur within the Western Hemisphere. Hurricanes and other tropical storms are caused by warm water and moist, warm air, which are readily found in the tropics. A.4. Oceanic Species The Caribbean region represents the greatest concentration of 4000 metres marine biodiversity in the Atlantic Ocean Basin7. Since the Caribbean nations depend on the condition and the beauty of the natural world to generate income, the conservation of the abyssal zone region’s biological diversity is not only linked to social, cultural, and political conditions, but also to the economic realities of the region. Although the marine component of biological diversity is of immense importance to humankind, knowledge about the 6000 metres status of marine living resources and ecosystems is less complete than that of terrestrial ecosystems. hadal zone The ocean is much richer in species than the land. The Carib- bean Sea marine ecosystem has the highest number of regionally endemic species in the world8. This is due to the geographic iso- lation of the Caribbean Sea from other oceanic regions. Atlantic deep-sea lobster (Acanthacaris caeca), Caribbean lobster (Meta- nephrops binghami), Bahamas sawshark (Pristiophorus schroed- eri), and Caribbean roughshark (Oxynotus caribbaeus) are sev- eral examples of endemic marine species found in the Caribbean Sea. All species of marine turtle, except for the flatback Natator( depressus) breed in the region. The critically endangered Kemp’s Ridley sea turtle (Lepidochelys kempii) and the West Indian Manatee (Trichecus manatus) exist only in the region. 11,000 metres A.3. Influences on the Ocean The ocean’s movement is controlled by currents. Ocean cur- rents are created from forces such as planet rotation, wind, tem- perature and salinity differences, and the gravitation of the moon acting upon the water. Winds are created as warm ocean currents from the tropics move towards the poles releasing warm air, and cold ocean currents move from the North and South poles towards the tropics bring- ing cool air. Wind drives the currents and waves found in oceans, which are necessary to circulate food. Hawksbill Turtle (Eretmochelys imbricata) The main oceanic current in the Caribbean Sea is an extension of National Environment & Planning Agency. (n.d.). Your environment & you: biodiversity: protect- the North Equatorial and South Equatorial currents, which enter ed animal species of Jamaica. Retrieved from: nepa.gov.jm/yourenv/biodiversity/species.htm [Part 2/Section A] Open Ocean Ecosystems The Caribbean has a large concentration of marine fish including parrotfish, barracuda, tarpon, snapper, spotted butterfly, porcupine, sturgeon, and damselfish. Smaller fish tend to remain in close proximity to coral reefs, a habitat in which they find shelter and food. Larger fish (which prey on smaller inshore coral reef fish) tend to have a larger habitat area and are found offshore from the Caribbean islands. Other commonly found inhabitants within the Caribbean Sea include a variety of conch and other molluscs, Green Sea, and Loggerhead sea turtles, a variety of lobsters and eels, black tip, hammerhead and leopard sharks, various species of jelly fish and sting rays, and many different species of whales, both baleen and toothed. Species within the ocean are interdependent on one an- other. All organisms in the ocean, from baleen whales to tiny plankton, are essential members of the marine food West Indian Manatee (Trichechus manatus) web. The marine food web explains how all the species National Environment & Planning Agency. (n.d.). Your environment & you: biodiversity: protected animal species of Jamaica. Retrieved from: nepa.gov.jm/yourenv/biodiversity/species.htm in the ocean depend upon each other for food. The web is organized by trophic levels (feeding levels) where the smallest primary producers, single-celled plants or phyto- plankton, exist at the bottom and the tunas, sharks, and billfishes such as marlins exist at the top. Tropical Food Web National Oceanic and Atmospheric Agency (NOAA). (2006). ECOPATH modelling. Retrieved from: celebrating200years. noaa.gov/breakthroughs/ecopath/welcome.html [Part 2/Section A] Open Ocean Ecosystems The fishing industry within the Caribbean occurs within the Over 170 species are caught for commercial purposes, but most Caribbean Sea Large Marine Ecosystem. Large Marine Eco- of the catch is comprised of less than 50 species10. The principal systems or LMEs are the jurisdictional regions of the world’s species harvested in the nearshore ecosystem are Caribbean oceans, encompassing coastal areas from river basins and estuar- spiny lobster (Panulirus argus), coralline reef fishes, and conch. ies to the seaward boundaries of continental shelves and the outer The most important species harvested in the offshore Caribbean margins of the major ocean current systems. The Caribbean Sea Sea are migratory pelagic species such as yellowfin tuna, skipjack LME produces an estimated catch of 0.5 million metric tons9. tuna, Atlantic blue marlin, swordfish, kingfish, and dolphinfish. Since the year 2000 , the most valuable fish harvested (in eco- FISH CATCH BY COUNTRY nomic terms) were round sardinella species (herrings, shads, and sardines), marine pelagic species (tuna, marlin, and kingfish), and Caribbean spiny lobster and ark clams (Arcidae)11.