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Introduction | Background | What Animals are Included?
Why Conserve Marine Invertebrates? | What will the Document Cover?
Why Conserve Marine Invertebrates?
Conservation of biological diversity
Invertebrates make up a major proportion of all marine biodiversity. One argument for conserving biodiversity in its entirety — or as close to its entirety as possible — is simply our ignorance about the vast majority of marine organisms and ecosystems. Our taxonomic knowledge — which would allow us to answer questions as simple as "how many species are there?" — is sparse. Even worse, information on the biology and ecology of the vast majority of species is virtually non-existent (the exceptions are a handful of commercially very important species). We have a long way to go in understanding the complex interactions between species which form the basis of marine ecosystems, or the true value of these "ecosystem services" for the human species. Until we know more we need to exercise the precautionary principle by conserving as much biological diversity as possible.
Ecological roles
Invertebrates are an integral part of marine ecosystems, and play a number of roles which help to support the function and stability of the food chains and ecosystems upon which other animals and ourselves rely. For instance, marine invertebrates play a role in the cycling of nutrients, are essential for the breakdown of plant matter and other detritus, form the basis of many food chains (including those supporting commercial fisheries), provide habitat for other species (e.g. coral reefs), regulate populations of other organisms (plant and animal) through predation, parasitism and herbivory, and help maintain water quality by filtering large amounts of water during feeding.
Scientific / environmental values
Both as subjects for study and tools for research in a range of fields, marine invertebrates contribute to our knowledge of ecosystems and environments, genetics, physiology, biology, medicine, chemistry, physics and other areas. Some species can be directly utilised as indicators of environmental health or degradation.
Importance as food
Certain marine invertebrates are used extensively as human food, with exploited species including various molluscs (e.g. scallops, mussels, abalone, squid, octopus), crustaceans (e.g. prawns, lobsters, crabs) and echinoderms (sea cucumbers — trepang or beche-de-mer). Invertebrates are among the most valuable of fished species, accounting for a high proportion of fisheries income relative to the quantity harvested. For instance, in 1995-96 crustaceans and molluscs made up only 40% of the tonnage yet almost 75% of the dollar value of Australian commercial fisheries (Australian Bureau of Statistics). Molluscs and crustaceans are also collected by recreational fishers, while other invertebrate species, such as bristle worms and cunjevoi, are commonly exploited for use as bait.
Economic & medical values
Throughout the history of humankind, certain marine invertebrates have been targeted, because of their aesthetic qualities, for use in jewellery or as adornments. Particularly prized have been the shells of certain marine molluscs (e.g. trochus) and the pearls and shells of pearl oysters. In other areas, sponges have long been used in the cosmetic industry, while the medical potential of coral as a replacement for bone (in bone grafts etc) is a more recent development. Growth in the hobby of aquarium keeping is leading to increased trade in certain live marine organisms, particularly corals.
Throughout millions of years of evolution, marine invertebrates have developed complex chemical signals for everything from the regulation of spawning and larval settlement to defence against predators. The screening of marine invertebrates for novel compounds and bioactive substances is a rapidly expanding area of biotechnological and pharmaceutical research. Such compounds have a variety of potential applications, ranging from new drugs to "natural" antifouling paints for boats and other man-made structures.
Aesthetic / recreational values
Many people derive great enjoyment from hobbies which revolve around the collection or observation of marine invertebrates. These range from snorkelling and scuba-diving (with coral reefs being particularly popular) to shell-collecting, aquarium keeping and even just wandering along rocky shores looking in tidepools. In some instances, the aesthetic and recreational values of marine invertebrates also translate into enormous economic gains. The Great Barrier Reef, for example, experiences around 1.5 million visitor-days a year and is estimated to generate over $1 billion annually in tourism revenue.
Ethical reasons
As the above points demonstrate, there are a host of economic and other utilitarian reasons for focusing on the conservation of marine invertebrates. However, there is also a strong ethical argument, based on the inherent "right of existence" of all living organisms. While humans are currently the dominant species on earth, the enormous diversity of organisms with whom we share it are equally the product (and the survivors) of billions of years of evolution. For this reason alone they can be seen as entirely "deserving" of a chance to continue their existence, regardless of their immediate value or otherwise to human society.
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