The ballast water from ships carries marine organisms that have invasive potential. The International Maritime Organization Ballast Water Management Convention (2004) requires ballast water exchange or ballast water management (BWM) systems either onboard or ashore. Ships can be exempted on the basis of risk assessment, when exclusively sailing between specific ports or in an enclosed area. In reply to our questionnaire, the shipping sector argues that the North Sea is ecologically homogeneous and exemptions could therefore be granted. This paper proposes that the North Sea area is, in fact, not homogeneous in terms of hydrographical and biological conditions; therefore, ballast water is a relevant transport mechanism for organisms. Within the North Sea, the short shipping routes indicate a high risk for survival. We examined actual simulation models for ballast water risk assessment in the North Sea, and we have identified the major parameters that need to be included in such models. These models provided a basis; they further need to be combined and adapted for the purpose of evaluating the rationale for an exemption. We concluded that exemptions from BWM are not recommended for the North Sea area. Anticipating the Ballast Water Management Convention, ship owners might do well to study possibilities for installing BWM systems onboard.

Monitoring, Reporting and Verifi cation (MRV) of emissions on board has been proposed as a measure to reduce global greenhouse gas (GHG) emissions. The requirements for MRV are set by two legislative bodies, the European Union (EU-MRV) and the International Maritime Organization (IMO-DCS) and ships have to comply with them. However, current maritime practices do not permit the right implementation of MRV and best practices can only be developed after a certain time of experience. A solution could be the application of the diff erent existing emission calculation methods on the phase of MRV where it is most useful. This contribution explores which method could be useful as maritime best practices and could meet the goals of EU-MRV and IMO-DCS. Eleven existing methods have been assessed by a set of questions based on key MRV elements found in literature. Methods have been classifi ed within Theoretical Based Methods (TBM) and Ship Based Methods (SBM). TBM methods may not comply with the monitoring phase of MRV but could be feasible as alternative method when activity data from ships are extracted. On the other hand, SBM methods seem to be the most appropriates to comply with MRV specifi cations, but need more investments on board and therefore require best practices regarding the way of application. The assessed methods are already available, possibly suitable to be used for monitoring, and therefore applicable as early best practices, with the understanding that some of the methods are theoretical, based on assumptions, and often too general. Nevertheless, a diff erent approach like the one presented in this contribution may be supportive in the understanding of MRV on board. Sažetak Praćenje, izvješćivanje i verifi kacija (MRV) emisija na brodu predloženi su kao mjera za smanjenje globalne emisije stakleničkih plinova. Zahtjeve MRV-a postavila su dva zakonodavna tijela, Europska unija (EU-MRV) i Međunarodna pomorska organizacija (IMO-DCS), a brodovi ih moraju ispuniti. Međutim, trenutna pomorska praksa ne dopušta ispravnu provedbu MRV-a, a najbolje prakse mogu se razviti tek nakon stečenog iskustva. Rješenje može biti primjena različitih postojećih metoda izračuna emisije u onoj fazi MRV-a gdje je to najkorisnije. Ovaj rad istražuje koja bi metoda mogla biti korisna kao najbolja pomorska praksa i koja bi mogla ispuniti ciljeve EU-MRV i IMO-DCS. Jedanaest postojećih metoda bilo je procijenjeno uz pomoć skupa pitanja temeljenih na ključnim MRV elementima koji se nalaze u literaturi. Metode su podijeljene na Teorijske metode (TBM) i Brodske metode (SBM). TBM metode možda nisu u skladu s fazom praćenja u sklopu MRV-a, ali mogu biti izvedive kao alternativna metoda kad se s brodova dobiju podaci o aktivnostima. S druge strane, čini se da su SBM metode najprikladnije za udovoljavanje specifi kacijama MRV-a, ali je potrebno više ulaganja na brodu i stoga su potrebne najbolje prakse u primjeni. Procijenjene metode su već dostupne, moguće ih je koristiti za praćenje, te se primjenjuju kao rane najbolje prakse, imajući na ...