Impacts of shipping on the biodiversity of large marine vertebrates: persistent organic pollutants, sewage and debris.

Only in the last decade has there been recognition that marine ecosystems worldwide are suffering a massive decline in biodiversity and irreparable alterations to ecosystem functions. The capacity of oceans to recover from global perturbations and, thus, to maintain ecosystem goods and services is rapidly weakening. Climate change, pollution, overfishing, introduced species and habitat degradation have been identified as the principal causes of marine biodiversity loss and thus priorities for conservation intervention. The Mediterranean Sea is representative of such extreme conditions resulting from persistent historical impact sustained over thousands of years of human development, settlement, commerce and resource exploitation. Currently, there are 601 cities with a population of 10,000 or more inhabitants along the Mediterranean coasts and 175 million tourists a year visit these shores. An enclosed sea such as the Mediterranean is particularly vulnerable to ship-associated impacts due to a high-volume of shipping routes, long history of use, and sensitive shallow and deep-sea habitats. Over the past half century, shipping has greatly expanded in the Mediterranean Sea. Between 1985 and 2001, a 77% increase was recorded in the volume of ship cargo loaded and unloaded in Mediterranean ports. An estimated total of 200,000 commercial ships cross the Mediterranean Sea annually and approximately 30% of international sea-borne volume originates from or is directed towards the 300 ports in the Mediterranean Sea. These values are expected to grow three or four fold in the next 20 years. It is logical, then, to predict that there will be various maritime-associated impacts on marine biodiversity and that these are also expected to grow at an alarming rate. These impacts are due to ship pollution and emissions, collisions and noise, grounding and anchor damage, and transportation of non-indigenous species. This review is the first attempt, as far as we know, to present and discuss these impacts scientifically, comprehensively and from a multi-disciplinary perspective in an effort to identify potential management and collective mitigation measures. We are optimistic that such a first and important step will initiate international and regional dialogue and pragmatic multi-lateral efforts towards addressing these serious issues in the Mediterranean