The history of ichthyology in Africa is reviewed. From the time of the Ancient Egyptians to the present, more than 3200 species have been discovered, drawn and described. Michel Adanson initiated the first material collections during the 18th century. During the 19th century, the work of travelling scientists (Étienne Geoffroy Saint-Hilaire, Andrew Smith) and explorers (including Mungo Park, Pierre Savorgnan de Brazza and Henry Morton Stanley) added substantially to developing zoological collections from their field trips. At that time, many species descriptions were based on fish preserved in these collections. Towards the end of the 19th and into the early part of the 20th century, knowledge of African fishes was greatly enhanced, especially through the work of Georges A. Boulenger, Albert C.L.G. Günther and Franz Steindachner, who, respectively, described 640, 119 and 53 species. The majority of the naturalists working in Africa during the middle and later parts of the 20th century tended to specialise in particular groups. In addition to conventional systematic studies, there was a steady rise in the numbers of contributions invoking genetics, specific parasites, and electrophysiology, amplifying fish identification using criteria other than morphology. These methods have proved helpful in finding explanations for the radiation of cichlids in the Rift Valley Lakes of East Africa, one of the most rapid and extensive involving vertebrates. Blending all these methods, descriptions of hitherto unknown species continue to be published. Whereas, until the mid-20th century, descriptions of new species and inventories of existing ones were the principal objectives of ichthyology, interests during the last 50 years have moved much more to the ecology of fish and to its application in aquaculture and aquariology: it is only during this period that most of the publications dealing with the biology and ecology of freshwater fishes and the science of fish culture have appeared. Brief biographies of the modern ichthyologists are presented, together with outlines of their main contributions.

At least 47 km of riverbank in the UK has been protected by willow spiling during the last 20 years and willow spiling is now the most widely used willow-based method for erosion control in the UK. Long willow canes are woven around vertically driven willow poles and because structures are living, resistance to erosion increases over time. Willow spiling has, alongside its geotechnical stabilisation function, numerous ecological and economical benefits for river restoration, habitat enhancement and community engagement. In this review, we select eight critical factors to consider when applying the method, based upon previous research and practical experience, and we explore knowledge gained from nearly 140 UK willow spiling projects. Information on performance has been collected from 27 % of the projects. Of these, 59 % were very successful, 30 % involved partial failure and 11 % failed completely. Although extreme flooding or drought can cause failure, most of the failures could have been limited by a better understanding of the site conditions in relation to willow requirements, by correct installation, by using good quality willow and by carrying out prompt repairs. Reasons for failure are documented and discussed. The importance of monitoring and maintaining the site after construction is emphasised.

The salmonid arctic charr Salvelinus alpinus (L.) is one of the most widespread fishes in the world and is found farther north than any other freshwater or diadromous fish, but also in cool water farther south. It shows a strong phenotypic, ecological, and life history diversity throughout its circumpolar range. One particular side of this diversity is the frequent occurrence of two or more distinct charr morphs in the same lake. This polymorphism has been termed ‘the charr problem’. Similar cases are found in other postglacial fishes, but not with the extent and diversity as with the arctic charr. This review first treats the classical case, pioneered in an advanced way by Winifred Frost, of autumn and winter spawning charr in Windermere, England, and three other cases that have received much research interest in recent years: Thingvallavatn, Iceland; Loch Rannoch, Scotland; and Fjellfrøsvatn, Norway. Then a special kind of sympatry with one morph living permanently in the profundal zone, known from a few lakes in Europe, Russia and Canada and unique for arctic charr among postglacial fishes, is reviewed. Among them is a recently discovered charr at 450 m depth in Tinnsjøen, Norway, one of the few very deep lakes in the world. With examples, the concluding discussion focuses on the variation of arctic charr polymorphisms which extends from early stages of ecological segregation to cases of reproductive isolation and speciation; and on models to explain the charr problem. The exceptional diversity of arctic charr provides a unique potential for further progress in studies on ecologically driven evolution within the frames of modern theory of developmental plasticity, adaptive radiation and adaptive speciation.

Twenty years after model equations describing the in situ growth rates of phytoplankton were first devised and eight since their successful incorporation into a computer simulation was first published, we set out to affirm the general validity and utility of PROTECH (Phytoplankton RespOnses To Environmental Change). Elaborated originally for commercial purposes, PROTECH has been shown to be capable of simulating simultaneous seasonal fluctuations in the standing crops of several contrasting species of alga, making it attractive for testing the impacts of various simulated regimes for managing the growth conditions. These have been sufficiently convincing to persuade us to use PROTECH as a research tool; over a number of years, it has been used to simulate such ‘traditional’ problems of ecology as succession, competitive exclusion and species diversity, in the context of intermediate disturbance. In this paper, we review critically the workings of the model, especially how complex but consistent outcomes emerge in compliance with simple trait-based rules of community assembly. We affirm that temperature-specific growth rates of algae are strongly influenced by algal morphology, that slender species are tolerant of low average light exposure and that periodicity is related to species-specific characteristics of motility and buoyant behaviour. The results of some applications of PROTECH are presented, simulating responses of the phytoplankton community to adjustments in nutrient loading, light penetration and hydrological flushing rates; an explicit investigation of the sensitivity of population responses of Cyanobacteria to eutrophication is also reported, in the context of varying availabilities of combined inorganic nitrogen.

Considering future developments of PROTECH, we affirm the virtues of its central growth equations; we anticipate that future applications will mostly depend upon improved representation of the physical environments it seeks to simulate and that these may more frequently relate to aquatic systems other than the lakes and reservoirs for which it was originally devised.