Overall Conclusions on the Ballast Water Issue and Its Management Options - Global Maritime Transport and Ballast Water Management: Issues and Solutions - page 290

on the route, an approach to shallow waters, and the consumption of fuel during the
voyage. As a result, vessels fundamentally rely on ballast water for safe operations
as a function of their design and construction.
Transfer of Organisms via Ballast Water
Many ballast water studies conducted in different parts of the world proved that
ships substantially facilitate the transfer of aquatic organisms across natural barri-
ers. Almost all species types have been found in ballast water samples ranging from
unicellular algae, macroalgae, invertebrates to fi sh. It has also been confi rmed that
human pathogens are being transferred with ship's ballast water and at least every
9 weeks a new species is found along the coasts of ICES member countries, which
includes secondary species introductions. Voyage length critically affects the survival
rate of organisms in ballast water. However, the organisms can survive in ballast
water for a relatively long time. Some algae, in particular dinofl agellates, can form
cysts which sink to the ballast water sediment and may remain viable for several
years. There are also known cases when organisms have reproduced and expanded
their population inside a tank so that a single ballast water discharge from a ship can
be potentially threatening.
One might think that ballast water was moved with ships since more than
100 years and all species which may become ballast water transported have reached
the areas they can colonise, but this is not the case. Studies have shown that the
number of new non-indigenous species records is increasing since the last 50 years.
This can also be due to the focus of scientists on this subject starting at that time and
because of intensifi ed research especially over the last two decades. The increase of
newly found non-indigenous species by ballast water since the last 50 years may
also be related to ever increasing ship speed and sizes. With increased speed the
unfavourable conditions an organism is exposed to inside a ballast tank during
transit get shorter thereby increasing the en-route survival potential. With increasing
vessel size ballast tanks also tend to get bigger, which may further support organism
survival due to longer lasting favourable abiotic water conditions.
In short, many of the most negatively impacting species have arrived in ballast
tanks which triggered the interest to develop globally applicable organisms transfer
preventing measures, i.e., the International Convention for the Control and
Management of Ships' Ballast Water and Sediments (BWM Convention).
Ballast Water Management Policy
Due to the lack of implemented, internationally agreed ballast water management
standards, national BWM requirements arose. As shipping is a truly global busi-
ness, regionally or nationally different standards are a disadvantage and globally