The Anthropocene marks a period where human activity dominates Earth’s climate system. Since the Industrial Revolution, fossil fuel use, deforestation, and intensive agriculture have sharply increased greenhouse gases, raising global temperatures by an average of 1.19°C between 2014 and 2024—approaching the 1.5°C threshold. Atmospheric CO₂ has climbed from ~280 to over 420 ppm, intensifying ocean acidification, sea-level rise, and ecological disruption. This study introduces a new hypothesis: that disruptions in the natural water cycle also amplify climate change. Water trapped in bottled or packaged forms weakens carbon sinks and alters hydrological circulation. Industrialization and massive plastic bottle use reinforce this effect. Thus, climate mitigation should not only reduce emissions but also restore natural water flows. Key strategies include reducing packaged water, promoting clean tap water, expanding refill stations, and improving water treatment. Furthermore, it is recommended that the storage and circulation of bottled and packaged water be better regulated and managed to minimize disruption to the natural water cycle. Protecting water’s natural flow is crucial for maintaining global climate stability.

There has been much discussion about which is better, farmed (= aquaculture) or wild-caught fish (= capture-fisheries), with supporters and opponents of both approaches. On balance, aquaculture should be the better option because of the ability to control all aspects of production. The result is that farmed products are often cheaper than wild-caught equivalents. However, there are negative aspects to aquaculture, including habitat destruction, for example the removal of mangroves for the construction of shrimp farms, the effect of escapees on native fish populations, and the possible negative impact of pollution from organic material, pathogens and antimicrobial compounds. The use of wild-caught `trash` fish as a source of protein and oil for the diets of carnivorous fish species in aquaculture is unsustainable. In contrast with wild-caught fish, there is greater variability in supply because of overfishing, quotas imposed by governments, and the effects of adverse weather. Moreover, fishing in distant waters is expensive and hazardous. Certainly, the quality of the product is more difficult to control because the history of the catch is largely unknown. However, there are concerns about illegal fishing activities, and the capture of undersized specimens which impacts negatively on future stocking levels. For the forseeable future, there will be roles for both aquaculture and capture-fisheries to meet the increasing global demand for aquatic food.

The editorial in the last issue was evocative and thought provoking (Steinberg, 2024). Consequently, it is appropriate to include an Editor in Chief’s perspective on the manuscripts that are received and considered for publication. It is realized that the publication process is stressful for the authors, but success is euphoric. Authors strive to publish in top class refereed international journals with success contributing to career security and advancement. The utopian desire of editors is to publish well-written manuscripts describing excellent work that will be well received by the readership and contribute to the all-important journal metrics. In short, we live in a period dominated by impact factors, and the number of citations, article downloads and reads. There may be contractual obligations with the publisher regarding the number of articles to be accepted and published within a defined period. In short, there is pressure on editors and authors. So, what is the reality of the situation. To dispel one myth, not all submissions lead to publications. It is not unusual that only a small minority of the submissions are actually published. The developments in the publication process have been met with a veritable explosion in the number of manuscripts submitted to journals posing tremendous pressure on the editors to deal with them in a timely manner for the benefit of authors and journals alike. Many submissions will be culled during the initial quality checks. The rest need to be assessed in terms of the content. This is the principle role of the editors and referees. However, for the system to work effectively, referees need to provide fair, impartial comment. We do not need false praise from “friends” or antagonistic comments from competitors. The reports guide the editor to make informed judgements. Could the process by improved? Well, we are certainly open to suggestions! There are clearly interesting times ahead.

Since its inception ~6000 years ago, aquaculture has evolved to enable its survival and growth to become a major contributor of protein of high nutritional value for human consumption, thereby improving food security and reducing poverty. Best practices have been established and updated to reflect developments as they occurred. Currently, best practices reflect all aspects of production from site selection and especially location in terms of proximity to other farms, construction and maintenance of the facilities, management practices, stock selection and acquisition, nutrition, biosecurity, disease control, and processing. Concerns about aquaculture continue to be addressed, and include the effects of pollution, such as from uneaten food and feces on the aquatic environment, and the needs of other users of waterways, such as for recreation/tourism. Best practices have been formalized into accredited standards, such as ISO 9000, and form the basis of Certification by the Global Seafood Alliance. With the intensification of aquaculture, the provision of total food requirements became necessary for the farmed stock. This has led the development of feeds capable of providing all the nutritional needs of the farmed species. Concerns about the sustainability of some feed components, such as protein from trash fish, are ongoing. Disease management has progressed from a curative approach (= therapy) with chemicals/antibiotics to prophylaxis with vaccines, probiotics and plant products. Best practices encompass the most up to date technology, including engineering, life sciences and nanotechnology. For the future, aquaculture is likely to remain at the forefront of ingenuity with the goal of increasing the contribution to human nutrition.

The rapid expansion in aquacultural production in the years since the end of the Second World War has been matched by increases in the incidence and severity of disease. Thus, the number of diseases has increased together with losses. However, there has been a growing awareness of the need for and implementation of effective disease control strategies, i.e. to implement effective biosecurity procedures. Attention has focused on site location, water flow, diet and effective management procedures. The latter includes use of sensible hygiene and disinfection policies, movement restrictions and slaughter in the case of the most serious diseases. Advances have been made with combating disease from the initial emphasis on chemotherapy with inhibitory compounds including antibiotics to more modern prophylaxis procedures involving vaccines, non-specific immunostimulants, pre- and probiotics, bacteriophages and medicinal plant products. Challenges remain, but there is evidence of great ingenuity in aquaculture research to overcome obstacles for a sustainable future.

The majority of marine ammonia oxidizers belong to Thaumarchaeota , a phylum of Archaea, which is distributed throughout the water column. Marine surface waters contain distinct thaumarchaeotal phylotypes compared to the deeper ocean, but spatial dynamics of the surface-associated lineages are largely unsolved. This study of 120 seawater samples from the eastern Chinese marginal seas identified contrasting distribution and association patterns among thaumarchaeotal phylotypes across different dimensions. Horizontally, Nitrosopumilus -like and Nitrosopelagicus -like phylotypes dominated the surface water (3 m) of the Yellow Sea (YS) and East China Sea (ECS), respectively, along with increased abundance of total free-living Thaumarchaeota in ECS. Similar compositional changes were observed in the surface microlayer. The spatial heterogeneity of particle-attached Thaumarchaeota was less clear in surface microlayers than in surface waters. Vertically, the Nitrosopelagicus -like phylotype increased in abundance from surface to 90 m in ECS, which led to an increase in the proportion of Thaumarchaeota relative to total prokaryotes. This occurred mainly in the free-living fraction. These results indicate a clear size-fractionated niche partitioning, which is more pronounced at lower depths than in the surface water/surface microlayer. In addition, associations of Thaumarchaeota with other microbial taxa varied between phylotypes and size fractions. Our results show that a phylotype-resolved and size-fractionated spatial heterogeneity of the thaumarchaeotal community is present in surface oceanic waters and a vertical variation of the Nitrosopelagicus -like phylotype is present in shallow shelf waters.

For most of human history on the planet, food acquisition has depended upon hunter-gathering involving a nomadic lifestyle for comparatively small groups of individuals. By modern standards, the total population would have been very low. Then approximately 12,000 years ago agriculture developed in the Near East, i.e. the Neolithic Revolution, leading to long-term and increasingly large human settlements. For the first time, finding food did not need to be the dominant activity for everyone all the time. Waste and its disposal were unlikely to have been a concern to these people. However, the hunter-gatherer approach to aquatic food continued. Indeed, aquaculture was not developed until more than 4,000 years ago, initially in China, and involved the rearing of common carp (Cyprinus carpio). The utopian notion about these ancient times was that humans lived in harmony with the environment. Fast forward to the 1760s and the start of the Industrial Revolution in Europe and North America. By this period, the global human population had increased to excess of 800 million, and there was a movement of people from rural to larger urban areas. Natural resources began to be used excessively, and waste materials were dumped onto the land and into waterways; gaseous compounds were released into the atmosphere. Currently, the global human population has grown to almost 8 billion with economies relying on growth despite finite resources (realistically, can this attitude be maintained into the future?); pollution is a major issue. Macro and micro-pollutants, including plastics and fishing nets/lines, abound in previously pristine marine habitats. Television programmes document marine mammals injured by netting; empty plastic drinks bottles may be found floating against shorelines even in remote areas. It is apt to recall the comment of Dr. Sherry Rogers that “the solution to pollution is dilution”, although at long last there are serious efforts to combat pollution, and reduce waste, such as by recycling. We have been guilty of plundering resources, for example destroying forests for timber, and overfishing the seas/oceans almost to the extent of species extinction. Fortunately, at last, environmental issues have come to the fore, especially the problems associated with climate change leading to extreme weather patterns and enhanced temperatures. Societies are realizing the need to attain sustainability for all key activities. There has been a moratorium on whale hunting, which has led to a large-scale increase in the numbers of these large mammals. Nations are working on controlling fishing to protect key species. We are moving from reliance on fossil fuels, much of which is extracted from deep sea wells with the added problem of the accidental release of hydrocarbons into the surrounding waters. Renewable energy is in vogue, including the use of wind turbines and for the future, wave power. Aquaculture, which has seen rapid expansion since World War 2, is embracing sustainability, for example by researching alternatives to using large quantities of trash fish for protein and oil in diets for carnivorous fish. New technologies are embraced. Apart from providing high-quality food to increasing human populations, aquaculture is contributing to restocking aquatic systems with rare and endangered species, thereby preserving and enhancing biodiversity. At long last, society is recognizing the problem of a growing human population, which is devastating the planet. Now is the time for innovative solutions. There has never been a greater need for sustainable aquatic research.

This study sought to determine the effect of fermented medicinal herbs (FMH), i.e. cutchery (Kaempferia galanga), turmeric (Curcuma longa) and curcuma (Curcuma xanthorrhiza) in combination with molasses and probiotic drink (Yakult), administered orally on the hematological and physiological profile of striped catfish (Pangasianodon hypophthalmus). A complete randomized design (CRD) experiment was used with four levels of treatments, namely P0 (control), P1 (FMH 100 mL/kg), P2 (FMH 200 mL/kg) and P3 (FMH 300 mL/kg) of feed. The fish were kept in a farm in cages at 75 fish/m3 and fed with the experimental diets for 60 days. The results revealed that FMH (P2) dietary administration improved hematological and physiological profile of catfish, i.e total erythrocytes of 2.81 x 106 cells/mm3, hematocrit values of 39.00%, hemoglobin levels of 10.73 g/dL, total leukocytes of 11.41 x 104 cells/mm3, blood glucose 97.33 mg/dL, and total serum protein 4.10 mg/dL compared to controls with 1.89 x 106 cells/mm3, 32.33 %, g/dL, 9.67 x 104 cells/mm3, 67.33 mg/dL, and total serum protein of 3.10 mg/dL, respectively. Moreover, the diet improved special growth rate, feed conversion ratio, feed efficiency and the survival rate of catfish. The hematological and physiological profile of catfish improvement are considered to be due to the content of secondary metabolites of FMH, namely curcuminoids, vitamin C, essential oils, tannins, and flavonoids, which trigger immunostimulation. The presence of curcuminoids provide an antioxidant effect on cell membranes reducing erythrocyte cell membrane damage due to oxidation. Similarly, flavonoids are natural antioxidants, which are credited with the ability of reducing free radicals and anti-free radicals.

Over the last few decades, aquaculture has undergone a dramatic expansion in production, becoming a key source of food for people in many countries. Indeed, aquaculture has become extremely important for food security. However, the rapid expansion has led to many concerns, such as the effects of water shortages, pollution, disease and the depletion of natural fish stocks used as protein and fat sources for aquaculture diets. Against this backdrop, there has been a growing awareness of the need for sustainability to ensure the long-term future of aquaculture. Thus, there have been tremendous efforts made to incorporate the latest procedures to ensure sustainability. For example, the industry has not been slow to address the benefits of polyculture, offshore rather than coastal sites for mariculture, the use of aquaponics and land-based recirculation systems, and improved disease management, including mitigation against the adverse effects of pollution, such as the use of biofloc technology. The therapeutic approach to disease control has moved towards prophylaxis, notably immunoprophylaxis and the use of probiotics and phytobiotics. Unfortunately, there are challenges resulting from the effects of environmental change, i.e. global warming. Some solutions have been found by use of new technologies, including nanotechnology. All these aspects are considered in this review.

Fish from the aquaculture industry will continue to be one of the mainstays in meeting human animal protein needs. Various global challenges face the aquaculture industry. Starting from the issue of environmental degradation, water pollution, conversion of agricultural land and aquaculture, to diseases attacks and the use of antibiotics to control fish pests and diseases. The presence of antibiotics and insecticides in food is no longer acceptable. Therefore, it is necessary to find an environmentally friendly solution for this disease and disturbance of water and environmental pollution. The use of natural ingredients in the form of medicinal plants to increase fish immunity and treat infectious diseases is a promising option. Water and environmental pollution are increasingly inevitable and the use of plants for the bioremediation process is the right choice. This paper presents a review of research on the use of several plant species that may be used for the purposes of improvement of fish immunity, enhancement of antimicrobial activity, replacement of the role of antibiotics, improvement of fish growth, improvement of feed conversion, and water quality improvement of polluted waters.

This study sought to determine the effect of fermented medicinal herbs (FMH), i.e. cutchery (Kaempferia galanga), turmeric (Curcuma longa) and curcuma (Curcuma xanthorrhiza) in combination with molasses and probiotic drink (Yakult), administered orally on the hematological and physiological profile of striped catfish (Pangasianodon hypophthalmus). A complete randomized design (CRD) experiment was used with four levels of treatments, namely P0 (control), P1 (FMH 100 mL/kg), P2 (FMH 200 mL/kg) and P3 (FMH 300 mL/kg) of feed. The fish were kept in a farm in cages at 75 fish/m3 and fed with the experimental diets for 60 days. The results revealed that FMH (P2) dietary administration improved hematological and physiological profile of catfish, i.e total erythrocytes of 2.81 x 106 cells/mm3, hematocrit values of 39.00%, hemoglobin levels of 10.73 g/dL, total leukocytes of 11.41 x 104 cells/mm3, blood glucose 97.33 mg/dL, and total serum protein 4.10 mg/dL compared to controls with 1.89 x 106 cells/mm3, 32.33 %, g/dL, 9.67 x 104 cells/mm3, 67.33 mg/dL, and total serum protein of 3.10 mg/dL, respectively. Moreover, the diet improved special growth rate, feed conversion ratio, feed efficiency and the survival rate of catfish. The hematological and physiological profile of catfish improvement are considered to be due to the content of secondary metabolites of FMH, namely curcuminoids, vitamin C, essential oils, tannins, and flavonoids, which trigger immunostimulation. The presence of curcuminoids provide an antioxidant effect on cell membranes reducing erythrocyte cell membrane damage due to oxidation. Similarly, flavonoids are natural antioxidants, which are credited with the ability of reducing free radicals and anti-free radicals.

Environmental Microbiology ReportsVolume 13, Issue 3 p. 248-252 Correspondence What do we mean by viability in terms of 'viable but non-culturable' cells? Da-Shuai Mu, Corresponding Author Da-Shuai Mu [email protected] orcid.org/0000-0001-7260-6165 State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237 China For correspondence. *E-mail [email protected]; Tel. +86-0631-5688303. **E-mail [email protected]; Tel. +86-0631-5688303. ***E-mail [email protected]; Tel. +86-0532-82032767.Search for more papers by this authorZong-Jun Du, Corresponding Author Zong-Jun Du [email protected] State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237 China For correspondence. *E-mail [email protected]; Tel. +86-0631-5688303. **E-mail [email protected]; Tel. +86-0631-5688303. ***E-mail [email protected]; Tel. +86-0532-82032767.Search for more papers by this authorJixiang Chen, Jixiang Chen College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, 266003 China School of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou, 730050 ChinaSearch for more papers by this authorBrian Austin, Brian Austin Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, Scotland, UKSearch for more papers by this authorXiao-Hua Zhang, Corresponding Author Xiao-Hua Zhang [email protected] orcid.org/0000-0002-7428-7775 College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, 266003 China For correspondence. *E-mail [email protected]; Tel. +86-0631-5688303. **E-mail [email protected]; Tel. +86-0631-5688303. ***E-mail [email protected]; Tel. +86-0532-82032767.Search for more papers by this author Da-Shuai Mu, Corresponding Author Da-Shuai Mu [email protected] orcid.org/0000-0001-7260-6165 State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237 China For correspondence. *E-mail [email protected]; Tel. +86-0631-5688303. **E-mail [email protected]; Tel. +86-0631-5688303. ***E-mail [email protected]; Tel. +86-0532-82032767.Search for more papers by this authorZong-Jun Du, Corresponding Author Zong-Jun Du [email protected] State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237 China For correspondence. *E-mail [email protected]; Tel. +86-0631-5688303. **E-mail [email protected]; Tel. +86-0631-5688303. ***E-mail [email protected]; Tel. +86-0532-82032767.Search for more papers by this authorJixiang Chen, Jixiang Chen College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, 266003 China School of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou, 730050 ChinaSearch for more papers by this authorBrian Austin, Brian Austin Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, Scotland, UKSearch for more papers by this authorXiao-Hua Zhang, Corresponding Author Xiao-Hua Zhang [email protected] orcid.org/0000-0002-7428-7775 College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, 266003 China For correspondence. *E-mail [email protected]; Tel. +86-0631-5688303. **E-mail [email protected]; Tel. +86-0631-5688303. ***E-mail [email protected]; Tel. +86-0532-82032767.Search for more papers by this author First published: 26 April 2021 https://doi.org/10.1111/1758-2229.12953Citations: 1Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume13, Issue3June 2021Pages 248-252 RelatedInformation

Culturing has been the cornerstone of microbiology since Robert Koch first successfully cultured bacteria in the late nineteenth century. However, even today, the majority of microorganisms in the marine environment remain uncultivated. There are various explanations for the inability to culture bacteria in the laboratory, including lack of essential nutrients, osmotic support or incubation conditions, low growth rate, development of micro-colonies, and the presence of senescent or viable but nonculturable (VBNC) cells. In the marine environment, many bacteria have been associated with dormancy, as typified by the VBNC state. VBNC refers to a state where bacteria are metabolically active, but are no longer culturable on routine growth media. It is apparently a unique survival strategy that has been adopted by many microorganisms in response to harsh environmental conditions and the bacterial cells in the VBNC state may regain culturability under favorable conditions. The resuscitation of VBNC cells may well be an important way to cultivate the otherwise uncultured microorganisms in marine environments. Many resuscitation stimuli that promote the restoration of culturability have so far been identified; these include sodium pyruvate, quorum sensing autoinducers, resuscitation-promoting factors Rpfs and YeaZ, and catalase. In this review, we focus on the issues associated with bacterial culturability, the diversity of bacteria entering the VBNC state, mechanisms of induction into the VBNC state, resuscitation factors of VBNC cells and implications of VBNC resuscitation stimuli for cultivating these otherwise uncultured microorganisms. Bringing important microorganisms into culture is still important in the era of high-throughput sequencing as their ecological functions in the marine environment can often only be known through isolation and cultivation.

Natural plant dietary supplementation in aquafeed could be used as an effective way for increasing the immunocompetency and disease resistance of fish. The current study aimed to investigate the potential effects of dietary Moringa oleifera leaf powder supplementation on the immune response, antioxidant status, and disease resistance against Aeromonas hydrophila in Oreochromis niloticus. A total of 180 fish (of 2.6 ± 0.5 g average weight) were randomly divided into three groups and fed on basal diet (= controls), and 1.5 and 5% (w/w) M. oleifera leaf powder incorporated into diets for 60 days. After the feeding trial, fish were challenged with A. hydrophila and continued on the same feeding regime during the next 2 weeks. Oral administration of O. niloticus fry with M. oleifera leaf powder led to significantly enhanced immune responses, i.e., respiratory burst, phagocytic and lysozyme activities, IgM level, and antioxidant enzyme activities, namely superoxide dismutase, catalase, and glutathion peroxidase levels in the liver, kidneys, and spleen. Conversely, the malondialdehyde level decreased significantly in the liver and kidneys. There was a significant increase in white blood cell count and non-significant change in red blood cell count and hemoglobin levels. Following challenge with A. hydrophila, all the fish in the experimental groups survived compared to only 20% of the controls; the relative percent survival was 100%. However, there was not any significant effect on growth as a result of feeding with the experimental diets. These results suggested that M. oleifera leaf powder-supplemented diets could enhance the immune response of O. niloticus fry and prevent disease caused by A. hydrophila.

Vibrio harveyi, which belongs to family Vibrionaceae of class Gammaproteobacteria, includes the species V. carchariae and V. trachuri as its junior synonyms. The organism is a well-recognized and serious bacterial pathogen of marine fish and invertebrates, including penaeid shrimp, in aquaculture. Diseased fish may exhibit a range of lesions, including eye lesions/blindness, gastro-enteritis, muscle necrosis, skin ulcers, and tail rot disease. In shrimp, V. harveyi is regarded as the etiological agent of luminous vibriosis in which affected animals glow in the dark. There is a second condition of shrimp known as Bolitas negricans where the digestive tract is filled with spheres of sloughed-off tissue. It is recognized that the pathogenicity mechanisms of V. harveyi may be different in fish and penaeid shrimp. In shrimp, the pathogenicity mechanisms involved the endotoxin lipopolysaccharide, and extracellular proteases, and interaction with bacteriophages. In fish, the pathogenicity mechanisms involved extracellular hemolysin (encoded by duplicate hemolysin genes), which was identified as a phospholipase B and could inactivate fish cells by apoptosis, via the caspase activation pathway. V. harveyi may enter the so-called viable but nonculturable (VBNC) state, and resuscitation of the VBNC cells may be an important reason for vibriosis outbreaks in aquaculture. Disease control measures center on dietary supplements (including probiotics), nonspecific immunostimulants, and vaccines and to a lesser extent antibiotics and other antimicrobial compounds.

Abstract This chapter describes the epidemiology, prevalence, distribution, risk factors, transmission, pathogenesis, clinical signs, diagnosis, treatment, prevention, control and effect of climate change on Aeromonas salmonicida infection in fishes.

This article presents the results of a workshop held in Stirling, Scotland in June 2018, called to examine critically the effects of low-dose ionising radiation on the ecosphere. The meeting brought together participants from the fields of low- and high-dose radiobiology and those working in radioecology to discuss the effects that low doses of radiation have on non-human biota. In particular, the shape of the low-dose response relationship and the extent to which the effects of low-dose and chronic exposure may be predicted from high dose rate exposures were discussed. It was concluded that high dose effects were not predictive of low dose effects. It followed that the tools presently available were deemed insufficient to reliably predict risk of low dose exposures in ecosystems. The workshop participants agreed on three major recommendations for a path forward. First, as treating radiation as a single or unique stressor was considered insufficient, the development of a multidisciplinary approach is suggested to address key concerns about multiple stressors in the ecosphere. Second, agreed definitions are needed to deal with the multiplicity of factors determining outcome to low dose exposures as a term can have different meanings in different disciplines. Third, appropriate tools need to be developed to deal with the different time, space and organisation level scales. These recommendations permit a more accurate picture of prospective risks.

The diagnosis of bacterial fish diseases has progressed from traditional culture-dependent methods involving the recovery of pathogens on agar-containing media and identification by examination of phenotypic traits. Newer approaches centre on culture-independent approaches. A problem with culturing is that it lacks sensitivity, tends to be slow, and its success depends on the composition of the media and incubation conditions employed. In contrast, culture-independent methods, now centring on molecular methods, are highly specific and sensitive. This raises an important issue that detection of very low numbers of bacterial cells does not necessarily imply the presence of clinical disease. Positivity could reflect background populations of the pathogen that may be present in the aquatic environment.