Even when massive exploitation of cetaceans is viewed as a problem of the past, thousands of cetaceans die each year in directed hunts. Cetaceans hunting continue around the world, making no distinction between developed and developing countries. Some developed countries such as Japan and Norway, ask the IWC (International Whale Commission) link a www.iwcoffice.org scientific whaling permits. Scientific whaling has been a controversial topic regarding to justifications given by these countries to kill a number of whales each year. Some aboriginal communities around the world have a special permit to take (for local consumption) a number of cetaceans per year.
By-catch refers to the incidental capture of non-target species in fisheries. It affects nearly every cetacean species and death from entanglement in fishing gear is often likely to be slow and painful. Some dolphin species often associate with certain tuna species, this has caused fishermen to use dolphin groups in order to set purse seines around them and get the tuna. Gill nets and tuna seines cause the greatest mortality, many thousands of animals per year in some fisheries.
The destruction of habitat is a serious threat to cetacean biodiversity, particularly for inshore and freshwater species. Harmful products include sedimentation, agricultural runoff, port construction, trash, hydrocarbons, plastics, sewage outfalls and oils. Cetaceans are long-lived and exist near the top of the food chain. This makes some of them to store contaminants from the environment in their blubber, link ANATOMIA which are then transferred to calves in maternal milk.
As the Acoustic section explains, the water environment as a sound transporter is essential for the cetaceans’ orientation, communication and reproduction. Sonic pollution is a factor that considerably affects these animals’ habitat. The problem of high intensity vessel traffic is translated in an increasement of underwater noise levels, which mask acoustics signals that are important for dolphins’ and whales’ survival.
¿Why conserve whales and dolphins?
The first valuable aspect to consider should be their ecological role. As organisms in the top of the food chain that posses few natural predators, research oriented to biology and ecology of cetaceans would help us comprehend marine environments’ vulnerability.
Because of their nature and fatty storage, they act as biological indicators of marine pollution, pesticides, to mention one example.
Some cetaceans have considerably economic value when alive. Whale and dolphin watching activities benefit hundreds of communities around the world. Economic benefits were estimated to be over U.S. $1000 million in 1998 (Hoyt 2001).
Cetacean carcasses can provide food and other products that have economic as well as nutritional value.
Protection Measurements
Cetaceans’ conservation status throughout the world has been classified by different organizations and commissions, and as one might expect, it’s constantly changing over time, depending on populations’ dynamics. One example of these classifications is the IUCN Red List, link a www.uicnredlist.org whichprovides a framework to classify species according to their extinction risk. In the World, there are currently 6 Endangered species, 4 Vulnerable species and 2 Critically Endangered species (Vaquita and Biaiiji), which means they are likely to disappear within the next decade.
Species or populations are listed by CITES link a www.cites.org -Convention on International Trade in Endangered Species of Wild Fauna and Flora-, under 3 Appendixes. All cetaceans not listed in Appendix I (no commercial trade allowed) are automatically listed in Appendix II (trade allowed, but regulated through export licensing). Since 1986, when the IWC –International Whale Commission- moratorium on commercial whaling came into effect, CITES has included in Appendix I all species of whales protected under the moratorium.
There is very few information in Costa Rica about direct or indirect effects on cetacean populations. Whether these effects are through captures or other incidental consequences, habitat destruction or loss, competition with fisheries, sonic pollution or global climatic change, is unknown at a national scale.
To begin with this conservation and evaluation process, we ought to have basic information from the se animals: social relationships, feeding specializations, hunting groups, to mention some. The latter could address the main problems and would led us to propose management solutions. Thus, the field research increasement to generate more scientific data seems to be the starting point for cetacean conservation in Costa Rica. This would show as a consequence environmental education programs and more people with access to knowledge and their environment, which could have a short and long-term effect on future policies and legislations.
In August of 2005, the first Workshop on Conservation Assessment Management Plan (CAMP) on Cetaceans of Costa Rica took place. We started (along other national NGO´s) the National Coastal Workshops of the Whale-watching decree in October of 2006.
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