Aquatic Biology (Marine and Freshwater)
Aquatic biologists study the special characteristics of life in environments dominated by water. This includes how organisms live in such environments and the management and conservation of them. Although aquatic biologists with a zoological training are primarily concerned with aquatic animals, a broad knowledge of chemistry, geology, hydrology, statistics, botany, and microbiology are extremely valuable in understanding the complexities of the systems with which they are dealing. The general principles of aquatic biology apply to both marine and freshwater systems but there is a traditional division of aquatic systems between Marine Biologists and Freshwater Biologists (limnologists).
Marine biologists seek to understand the physical and chemical environment of the seas and how these relate to the ecology of marine animals. Among other things, their studies often have practical applications. For example, they may study fish populations, assessing their productivity and establishing guidelines for their sustainable exploitation by man.
Marine biologists will include biological oceanographers, who study all animal groups in the oceans, as well as researchers who focus on the larger marine animals including commercially exploitable fish (see the section on fisheries biology).
Many of the latter contribute to managing this valuable resource by providing scientific advice to the fishing industry. The interests of marine biologists extend from the open sea to sandy and rocky shores and estuaries and lagoons. Many have the opportunity to use scuba diving on the job and have appropriate training in diving as a professional skill and abide by certain regulations.
Marine biologists are employed by various research institutes (for example, the Oceanographic Research Institute and KwaZulu Natal Sharks Board), government organisations and departments, museums, aquaria, and universities.
Freshwater biologists are concerned with understanding the functioning of inland water systems and the organisms in them. Water in South Africa is a scarce resource and freshwater biologists are often involved in the protection and use of natural waters, often in stimulating multidisciplinary teams with chemists, hydrologists, and geologists.
There are several job opportunities for limnologists in South Africa. These range from positions at the technical level to those requiring a doctorate in zoology. Limnologists may find employment with state departments responsible for monitoring and maintaining the quality of our limited water resources and the useful biological life they sustain (e.g. Department of Water Affairs & Forestry). Other employers of freshwater biologists include research institutes, universities, technikons, and firms of ecological consultants.
Fisheries biology is a slightly more specialised branch of marine and freshwater biology. Marine fisheries are especially well developed along the west coast of South Africa but freshwater fisheries and the culture of fish, shellfish (e.g. oysters and prawns) in both inland and coastal waters are becoming increasingly important as yields of natural stocks decline. Fisheries biologists study the rates of reproduction and growth of fish and fish stocks, factors that affect population sizes and distributions and methods of harvesting. They also assess the effects of harvesting or catch size on the remaining stocks of fish by means of mathematical models and use these to formulate guidelines for quotas that will ensure the sustainable use of valuable commercial stocks. In addition to specialized knowledge of ichthyology, fisheries biologists usually have some training in other disciplines like ecology, limnology, population dynamics, and oceanography. The mathematical modelling of fish populations requires a background in statistics and computing.
Training in fisheries biology usually starts at the postgraduate level, although some universities do offer undergraduate courses in fisheries biology. Employment opportunities exist with various fisheries and ichthyological institutes, the commercial fishing and aquaculture industries, technikons and universities. Good fisheries biologists seldom have trouble finding permanent positions.