Recently, annual swarm of invasive Erythrean schyphozoan RhopilemanomadicaGalil, 1990 appeared along Egyptian Mediterranean coasts causing beach closures and fishing problems. The present study conducted survey and field monitoring on R. nomadica during blooming season in the Egyptian Mediterranean coast throughout three consecutive years (2015-2017). Three main features of R. nomadica bloom were addressed; viz starting date, duration and maximum density of aggregation. In 2015, the bloom started on 28 July, and over the following two years the bloom starting date shifted earlier being 19 July in 2016 and 15 June in 2017. The duration of the bloom varied yearly giving the longest duration in 2017 when the bloom continued in high density for a month. The highest density of R. nomadica was about 896 medusae/1000 m3 in 2017. The medusae diameter ranged between 21 to 112 cm. The average bell diameter for each year displayed gradual increasing values over the years. The consistent annual R. nomadica blooming was attributed to the high level of eutrophication and ecosystem degradation occurred along the Mediterranean coast since last decades. The shifting in the annual bloom starting date and duration may reflect the adaptation of R. nomadica to the climate change effect on the Mediterranean Sea temperature. Show less

The stocks of the Atlantic salmon (Salmo salar) in many rivers in North America and Europe have declined in recent years and are experiencing a crisis. Despite their high degree of legal protection, the quality of their aquatic environments within rivers and in the sea, including local coastal waters, appears to be deteriorating. Salmon survival, has declined both within the sea and within rivers. The status of the Atlantic salmon stocks is considered here, together with the adverse effects of different sources, and those steps that may need to be taken to improve the condition of the salmon. This paper is intended to assist management bodies in taking steps to resolve the problems that exist for salmon, both within rivers and in the sea. It makes particular use of information available on the River Dee in Scotland. Show less

Many marine and freshwater fisheries are now in a very poor state, and many fish stocks are close to collapse. There is a need to manage fisheries more carefully, especially since fishing can affect other aspects of the environment. It is also important to reduce the adverse effects of climate changes upon the marine and freshwater environments, fishes, and other animals, and the need to manage other human activities taking place in the sea, to improve the marine environment and protect the wildlife and the fishing activities. Marine pollution, includes human waste materials, chemicals and plastics, and there is also noise and substrate vibration, from industrial and other activities that may affect both the abundance and quality of fishes and other marine animals. This paper deals with fisheries management, and environmental protection, and concludes that fishermen, fisheries scientists, fisheries managers and environmental interests must work closely together, if fishes are to be adequately protected, and fisheries are to be better managed. It describes current systems of management. It especially draws attention to the importance of moving towards an ecosystem-based approach to fisheries management. Such an approach aims to manage all those human activities that have an impact upon the marine environment and its life forms. Show less

Underwater sounds from human sources can have detrimental effects upon aquatic animals, including fishes, and currently such sounds are very common. It is important to examine such anthropogenic sounds and their effects upon aquatic animals, so that it is possible to introduce protective regulations. Fishes and other aquatic animals can detect underwater sounds and use them to obtain key information about the environment around them. Sounds travel rapidly over great distances in water and can provide detailed information on the presence of prey, predators, and related fishes, while the overall acoustic scene provides the fishes with key information about their environment. Although some of the background noise is generated by natural sources, including the precipitation of rain and snow, and wind and waves, many underwater sounds now come from anthropogenic sources, often termed “noise”. Some of these human-made sounds can kill or injure fishes and other aquatic animals, also impairing their hearing, and altering their behavior. There is a need for more work on the impact of human-made underwater noise upon the fitness of aquatic animals. This paper considers the gaps in information that must be resolved. The effects that need to be considered include death and injuries, physiological effects, and changes in behavior. Show less