Sounds awkward in English but there are many museum websites that use the phrase. There are even courses you can study. See below.

However, you don't say what objects are being conserved in the coastal and marine areas. Sounds more like environmental conservation than object conservation. More context would be useful.

Saludos

I presume this refers to things that are conserved. In this case it appears to be ecological conservation, but the term "objects of conservation" can apply equally to artworks, buildings, etc.

"10. A plan of conservation tasks for a Natura 2000 site shall contain:
1) a description of the boundaries of the site and a map of the Natura 2000 site;
2) the identification of the existing and potential threats for the
preservation of a favourable conservation status of natural habitats and the species of flora and fauna and their habitats which are the objects of conservation;
3) the objectives of conservation measures;
4) the determination of conservation measures, with an indication of the entities responsible for their implementation and the areas of their implementation, including in particular the measures for:
a) the active conservation of natural habitats, the species of flora and fauna and their habitats,
b) monitoring the status of the objects of conservation and monitoring the achievement of the objectives referred to in
point 3,
c) complementing the level of knowledge concerning the
objects of conservation and the factors affecting their conservation"
http://www.europarl.europa.eu/document/activities/cont/20091...

The Wikipedia page on Conservation in the UK uses the term "objects of conservation" to apply to any sort, historical, cultural or natural:
http://en.wikipedia.org/wiki/Conservation_in_the_United_King...

It seems that OC as an abbreviation for "objetos de conservación" is not a one-off usage in this document; it occurs in several places:
https://www.google.es/search?num=100&q="objetos de conservac...

So it would be nice to retain it. One advantage of "objects of conservation" is that the abbreviation works in English too.

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Note added at 1 hr (2013-09-20 10:03:25 GMT)
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A few further references to reinforce this proposal. From the FAO:

"The Area Conservation Plan (CAP) is the methodology used by TNC to identify objects of conservation, pressures, pressure sources, successful measures and strategies for a priority site."
http://www.fao.org/docrep/006/y5305b/y5305b02.htm

Winston Churchill Memorial Trust (UK):
"Novel ecosystems, those that have new species combinations arising through either species invasions or environmental change, are now widespread and could become objects of conservation for their own sake in the future."
http://www.wcmt.org.uk/reports/943_1.pdf (p. 139)

Convention on Biological Diversity/United States Agency for International Development:
"During this first workshop, a vision was established for the Reserve and the objects of conservation were selected. The objects selected were both natural and cultural."
http://www.cbd.int/doc/pa/tools/Indigenous peoples and prote... (p. 8, and several further instances in this document).