Evaluation model and management strategy for reducing pollution caused by ship collision in coastal waters

2020 ◽  
pp. 105446
Author(s):  
Yao Yu ◽  
Liming Chen ◽  
Yaqing Shu ◽  
Wanying Zhu
Keyword(s):  
Coastal Waters ◽  
Management Strategy ◽  
Evaluation Model ◽  
Ship Collision

Modelling and simulation of ship collisions in port and coastal waters

2021 ◽  
pp. 147509022198918
Author(s):  
Chien-Chang Chou
Keyword(s):  
Coastal Waters ◽  
Maritime Transportation ◽  
Critical Factors ◽  
Ship Maneuvering ◽  
Collision Model ◽  
The Past ◽  
Sea Current ◽  
Ship Collision ◽  
Comparison Of The Results ◽  
Collision Models

Navigational safety is an important issue in maritime transportation. The most frequent type of maritime accident in the port and coastal waters is the ship collision. Although some ship collision models have been developed in the past, few have taken account of wind and sea current effects. However, wind and sea current are critical factors in ship maneuvering. Therefore, based on the previous collision model without wind and sea current effects, this study further develops a ship collision model with wind and sea current effects. Finally, a comparison of the results for the proposed collision model in this study and the ship maneuvering simulator is shown to illustrate the effectiveness of the proposed mathematical model in this paper, followed by the conclusions and suggestions given to navigators, port managers, and governmental maritime departments to improve navigational safety in port and coastal waters.

scholarly journals DISTRIBUSI SPASIO-TEMPORAL POPULASI RAJUNGAN (Portunus pelagicus) BETINA MENGERAMI TELUR DI PERAIRAN PESISIR LAMPUNG TIMUR

2015 ◽  
Vol 6 (2) ◽  
pp. 95
Author(s):  
Zairion Zairion ◽  
Yusli Wardianto ◽  
Achmad Fahrudin ◽  
Mennofatria Boer
Keyword(s):  
Water Depth ◽  
Coastal Waters ◽  
Management Strategy ◽  
Temporal Distribution ◽  
Fishing Gear ◽  
Portunus Pelagicus ◽  
Temporal Occurrence ◽  
Breeding Seasons ◽  
Two Peaks ◽  
One Way Anova

Distribusi spasio-temporal populasi rajungan betina yang mengerami telur (BEF) telah dikaji di perairan pesisir Lampung Timur. Penelitian dilakukan pada tiga stratifikasi kedalaman perairan: <5 m (strata S1), antara 5-10 m (strata S2), dan >10 m (strata S3) serta empat sub-area (A1-A4) di setiap stratum dari bulan Maret 2012-Februari 2013. Kelimpahan populasi rajungan BEF diindikasikan dengan proporsi rajungan BEF/betina tidak mengerami telur (NBF) dan BEF/total individu. Perbedaan proporsi dianalisis dengan uji ANOVA satu arah. Hasil penelitian menunjukan bahwa proporsi rajungan BEF bervariasi secara spasial, ditemukan mulai dari strata S1 dan meningkat ke strata S3. Daerah pemijahan dan pembiakan yang dominan terdapat pada kedalaman air >5 m dan di sub-area A2 dan A3. Secara agregat, BEF ditemukan sepanjang tahun dengan dua puncak kelimpahan (Mei dan September-Oktober) sebagai puncakmusimpemijahan dan pembiakan. Proporsi rajungan BEF secara spasio temporal tumpang tindih dengan daerah penangkapan rajungan pada hampir semua musim. Diperlukan strategi pengelolaan pemanfataan yang sesuai untukmenunjang keberhasilan reproduksi, diantaranya penangkapan menggunakan alat yang dapat mempertahankan BEF dalam keadaan hidup selama terperangkap, kemudian melepaskannya atau memeliharanya di area tertentu sampai menetaskan telurnya sehingga dapat meningkatkan produksi larva dan pada akhirnya dapat mempertahankan populasi dan stok.Spatial-temporal distribution of berried females (BEFs) Portunus pelagicus was studied in East Lampung coastal waters. An investigation was conducted at three water depth stratifications, i.e., less than 5 m (stratum S1), between 5-10 m (stratum S2) and more than 10 m (stratum S3), as well as four sub-areas (A1 A4) in each of stratifications from March 2012 to February 2013. The abundance of BEF population was indicated by their proportion to non-berried females (NBFs) and to the total individual crabs, while the differences among the results were tested by one-way ANOVA test. The results showed that the proportions of BEFs varied spatially, increased from stratum S1 to S3. Spawning and breeding seemed to dominantly occur at water depth more than 5 m and A2 and A3 sub-areas. BEFs were found throughout the year with two peaks of its occurrence, i.e. in May and in September to October, and those months were considered as peak of spawning and breeding seasons. The spatial and temporal occurrence of BEFs overlapped with crab fishing grounds in most fishing seasons. An appropriate fisheries management strategy is required for their reproduction success. Capturing crab by using eco-friendly fishing gear that render caught BEFs alive and releasing them or keeping them in certain area for hatching their eggs would enhance larvae production to maintain population and stock.

An improved AHP based fuzzy evaluation model for ship collision risk

2021 ◽  
pp. 1-9
Author(s):  
Jie Luo ◽  
Deling Wang ◽  
Yuan Gao
Keyword(s):  
Collision Avoidance ◽  
Comprehensive Evaluation ◽  
Evaluation Model ◽  
Fuzzy Comprehensive Evaluation ◽  
Risk Level ◽  
Fuzzy Evaluation ◽  
Collision Risk ◽  
Decision Making System ◽  
Solid Foundation ◽  
Ship Collision

In the research of ship collision avoidance and automatic collision avoidance decision-making system, collision risk level is especially important. To evaluate the risk of ship collision, the nature of the risk level of ship collision is analyzed. Based on the fuzzy comprehensive evaluation model based on improved AHP, the concepts of space collision risk and time collision risk are proposed, and the models for space collision risk, time collision risk and collision risk level are established at the same time. The model developed and perfected the concept of ship collision risk, and are more logical, laid a solid foundation for subsequent comprehensive evaluation.

Reproduction and embryonic development of the blue stingray, Dasyatis chrysonota, in southern African waters

2008 ◽  
Vol 89 (4) ◽  
pp. 809-815 ◽  
Author(s):  
David A. Ebert ◽  
Paul D. Cowley
Keyword(s):  
Life History ◽  
Reproductive Cycle ◽  
Coastal Waters ◽  
Management Strategy ◽  
Eastern Cape Province ◽  
Eastern Cape ◽  
Annual Reproductive Cycle ◽  
Life History Characteristics ◽  
Disc Width ◽  
Over Exploitation

Dasyatis chrysonota is perhaps the most common of the 14 whiptail stingray (Chondrichthyes: Dasyatidae) species known to frequent the temperate coastal waters of southern Africa and like other stingrays they possess life history characteristics that make them vulnerable to over-exploitation. First and 50% maturity (Dw50) were determined for 153 males and 204 females from the Eastern Cape Province of South Africa. Disc width (Dw) for first and Dw50 maturity was estimated at 392 mm and 395 mm Dw, respectively for males and at 500 mm and 505 mm Dw, respectively for females. The reproductive cycle of males, based on gonadosomatic (GSI) and hepatosomoatic (HSI) indices indicates that they are most active during the spring. Females appear to have an annual reproductive cycle with a maximum HSI occurring during the summer and autumn, but it declines steadily through the birthing season reaching a low in the late spring. Fecundity, following a nine month gestation period, averages 2.8 with a range of 1–7. Embryos at six different development stages are described. Dasyatis chrysonota, like other dasyatids, exhibit life history characteristics that make them vulnerable to overexploitation, therefore a precautionary management strategy is advised for this species.

As Inland Becomes Coastal: Shifting Equity and Flood Risk in the Amite River Basin (USA)

2021 ◽  
Vol 14 (3) ◽  
pp. 475-504
Author(s):  
Craig E. Colten
Keyword(s):  
Coastal Waters ◽  
Urban Areas ◽  
Management Strategy ◽  
Baton Rouge ◽  
County Level ◽  
Sea Levels ◽  
The Us ◽  
Rising Sea Levels ◽  
Coastal Louisiana ◽  
Policy Adjustments

Coastal Louisiana is experiencing the most rapid relative sea-level rise in the US due to a combination of a subsiding delta and rising coastal waters. Consequently, the influences of extreme coastal weather are reaching farther inland and impacting urban areas where traditional environmental policy, organised at the parish (county) level, is unable to address this changing flood risks. This situation is most prominent in the metro Baton Rouge region with the largest city situated upstream from two small, but rapidly growing, parishes. Following a massive flood in 2016, the upstream parishes have undertaken policy adjustments to facilitate the expulsion of water toward downstream neighbors and foster redevelopment in the floodplain. The lower parish has expressed concerns about the anticipated increases in discharge to be sent its way. Although the state is concerned with rising sea levels, it has not merged coastal and inland flood policy considerations. Downstream residents have little voice in upstream policy making and the absence of basin-wide management strategy perpetuates emergent risks and environmental injustices. As climate change drives coastal conditions inland, the misalignment between locally based governance and regional environmental realities will become more pronounced and exacerbate social injustices.

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