Prioritising surveillance for alien organisms transported as stowaways on ships travelling to South Africa

The global shipping network facilitates the transportation and introduction of marine and terrestrial organisms to regions where they are not native, and some of these organisms become invasive. South Africa was used as a case study to evaluate the potential for shipping to contribute to the introduction and establishment of marine and terrestrial alien species (i.e. establishment debt) and to assess how this varies across shipping routes and seasons. As a proxy for the number of species introduced (i.e. 'colonisation pressure') shipping movement data were used to determine, for each season, the number of ships that visited South African ports from foreign ports and the number of days travelled between ports. Seasonal marine and terrestrial environmental similarity between South African and foreign ports was then used to estimate the likelihood that introduced species would establish. These data were used to determine the seasonal relative contribution of shipping routes to South Africa's marine and terrestrial establishment debt. Additionally, distribution data were used to identify marine and terrestrial species that are known to be invasive elsewhere and which might be introduced to each South African port through shipping routes that have a high relative contribution to establishment debt. Shipping routes from Asian ports, especially Singapore, have a particularly high relative contribution to South Africa's establishment debt, while among South African ports, Durban has the highest risk of being invaded. There was seasonal variation in the shipping routes that have a high relative contribution to the establishment debt of the South African ports. The presented method provides a simple way to prioritise surveillance effort and our results indicate that, for South Africa, port-specific prevention strategies should be developed, a large portion of the available resources should be allocated to Durban, and seasonal variations and their consequences for prevention strategies should be explored further. (Résumé d'auteur

Water region and multiple ship detection for port surveillance

In this paper, we present a robust and accurate multiple ship detection system for port surveillance. First, water region is detected using a region-based technique. Second, ships are located by a cabin detector for the same port surveillance sequences. Third, a verification process is performed to remove the false detections of ships using the detected water region as contextual cues. We have analyzed our water region detection algorithm by experimenting on 5 sequences and we have found that it achieves an average pixel classification precision of 96.9% and a recall of 91.8%. The multiple ship detection system is tested on 3 different surveillance sequences. We successfully detect 133 ships out of 150 ships with a precision of 87.5% and a recall of 88.7%

A survey of potential users of the High Altitude Powered Platform (HAPP) in the ocean/coastal zone community

The results of a survey of the ocean/coastal zone community to determine potential applications of a High Altitude Powered Platform (HAPP) are reported. Such a platform, capable of stationkeeping for periods up to a year over a given location, could make frequent and repeated high resolution observations over a given region or serve as a high-altitude regional communications link. Users were surveyed in person and via a questionnaire to determine the desirability of the HAPP within the ocean/coastal zone community. The results of the survey indicated that there is strong interest in all areas of the user community (research and development, operational agencies, and private industry) in having NASA develop the HAPP

PSSA In The Baltic Sea : Protection On Paper Or Potential Progress?

This report analyzes the effectiveness of the mechanisms of the particularly sensitive sea area (PSSA) and associated protective measures (APMs) as adopted and applied in the Baltic Sea and their contribution towards achieving sustainable shipping in future scenarios.https://commons.wmu.se/wwf/1001/thumbnail.jp

Designing a constellation for AIS mission based on data acquisition of LAPAN-A2 and LAPAN-A3 satellites

Indonesia requires a maritime surveillance system that's capable to monitor its extensive waters territorial. One of the maritime standard navigation systems named AIS (Automatic Identification System), which is based on GPS and VHF digital communication, have enabled the ship monitoring in a real-time. By placing AIS receiver on the satellite, its coverage will be larger compared to the one usually placed on the seashore by maritime authority. Orbiting the AIS receiver prompted appearing the limitation of Time Division Multiple Access (TDMA) technology so the probability of ship detection would decrease drastically due to a huge number of heard ship signal simultaneously. This paper describes the design of satellite constellation for Indonesian maritime surveillance based on the result of the AIS data acquisition by LAPAN-A2 and LAPAN-A3 satellites that operate in both equatorial and polar orbit