Many professionals regard the study of history as a waste of time. I can understand this sentiment where research proceeds rather automatically and largely without concern for possible social censure, but where societal forces directly complicate the agenda involved, there is reason for proceeding with a more open mind. Ignorance of the past invites reinventing the wheel; not only with respect to specific theories or models that were designed in some past era but never fully tested, but also to more general points of view that may extend beyond the immediate science of the question. Meanwhile, within most fields of knowledge there are constant attempts at reinvention; in many of these theory or research paradigms may become stale or stagnant. But just as often societal evolution may produce new agenda, including ones that require wholly new perspectives. The biodiversity movement of the past fifteen years is a good example of such forces in action. Human population pressures increasingly test the planet's ability to renew itself, a momentum that has caused conservationists and planners to move away from single-species and intra-national forms of management and toward larger-scale, interdisciplinary, understandings of the socio-natural processes at work.

An extensive literature has appeared since 1990 on the study of ‘no-take’ marine reserves and their potential to make significant contributions to the conservation and management of fisheries, especially in tropical environments (see Polunin 1990; Roberts & Polunin 1991; DeMartini 1993; Roberts 1997; Allison et al. 1998; Guénette et al. 1998). The literature describes many potential benefits of marine reserves to fisheries, including increases in spawner-biomass-per-recruit and increases in larval supply from protecting ‘source’ populations (Jennings 2000). The important word here is ‘potential’. Some claims made by advocates of marine reserves might be regarded as optimistic, whereas critics of reserves might sometimes have been unduly harsh. Conservation goals for marine reserves are often poorly defined, and differences of opinion regarding the efficacy of reserves for fulfilling any of their stated goals can frequently be attributed to a lack of good information with which to predict their effects. Here, we critically examine the literature from 1990–2001 to determine (1) the relative effort put into empirical and theoretical approaches to predict reserve effects, and (2) the quality of empirical evidence available to support theoretical predictions. It is not the purpose of this article to single out particular studies for criticism (although this is sometimes inevitable to provide examples), nor to draw conclusions concerning the efficacy of marine reserves.

This review of polar marine ecosystems covers both the Arctic and Antarctic, identifying the major threats and, where possible, predicting their possible state(s) in 2025. Although the two polar regions are similar in their extreme photoperiod, low temperatures, and in being heavily influenced by snow and ice, in almost all other respects they are very different. The Arctic Ocean is a basin surrounded by continental landmasses, close to, and influenced by, large populations and industrial activities. In contrast, the Southern Ocean is contiguous with all the other great oceans and surrounds a single land mass; Antarctica is remote from major centres of population and sources of pollution. Marine environments in both polar regions have been highly disturbed by fishing activity, but, in terms of pollution, some areas remain among the most pristine in the world. There are, however, both local and global pressures. Over the 2025 time horizon, the greatest concern for the Arctic is probably the ecological implications of climate change, particularly insofar as sea ice extent and duration are likely to be affected. Such changes are not expected to be as pronounced in the Southern Ocean over this time period, and concerns are related more to direct threats from harvesting of marine living resources, and the ability to manage these fisheries sustainably. In both polar regions, the capacity of marine ecosystems to withstand the cumulative impact of a number of pressures, including climate change, pollution and overexploitation, acting synergistically is of greatest concern.

Von Hippel and von Hippel (1998) suggested that Viagra had the potential to replace an existing demand for certain wildlife species used in traditional Chinese medicine (TCM) to treat erectile dysfunction (ED). Von Hippel and von Hippel (2002) attempted to show that this potential is becoming a reality.

Ecological and socioeconomic aspects of subterranean hydrosystems have changed during the past 40–50 years. The major environmental pressures (mainly anthropogenic ones) impact the quantity and quality of groundwater resources and the state of subsurface ecosystems, and it is expected that the environmental pressures on groundwater will continue, at least until 2025, unless new environmental policies change this state of affairs. The world demographic increase and the general rise of water demand constitute one of the major environmental pressures on groundwater ecosystems especially in less developed countries in Africa, Asia and South America. Specific human activities leading to the depletion of groundwater reserves include agricultural practices, landscape alteration, urbanization demand for domestic and public drinking water, various industrial activities such as thermoelectric production and mining, and the rise of tourism in coastal areas. Climate change is contributing to the water crisis too, especially in areas with arid climate and/or in some humid monsoonal countries. The overload of aquifers with pollutants derived from agriculture (fertilizers and pesticides), from industry (release of hydrocarbon chemicals, especially spills), from waste and industrial waters, from domestic and industrial landfills, from the infiltration of pollutants from surface and from the intrusion of saline water affect groundwater quality. The dangerous increase in contaminated subsurface sites with chemicals and microbial pathogens brings with it health risks to humans. Changes of redox condition in groundwater zones, changes of biological diversity, vegetation changes with modification of agriculture practices and impacts at the biosphere scale, such as the increase in the concentration of nitrous oxides in the atmosphere, all impact groundwater ecosystems. Groundwater ecosystems must be better investigated and understood. Economic, social and ecological lines of thinking have to be combined in order to achieve meaningful policies for the sustainable development of groundwater reserves and for the protection of subsurface ecosystems. Practical measures and ideas for the development of policies up to the 2025 time-horizon should improve the sustainable usage of the world's groundwater resources.

Feral swine (Sus scrofa) adversely affect the environment in many of the places where they have been introduced. Such is the case in Florida, but quantification and economic evaluation of the damage can provide objective bases for developing strategies to protect habitats. Swine damage to native wet pine-flatwoods at three state parks in Florida was monitored from winter 2002 to winter 2003. Economic valuations of damage were based on the US dollar amounts that wetland regulators have allowed permit applicants to spend in attempts to replace lost resources. The parks had different swine management histories and the damage patterns differed among them over time. Swine were intensively removed in 2000 from the first park, and it initially had the lowest habitat damage at 1.3%, but as a result of natural and artificial population growth this damage rose to 5.4% by the conclusion of the study, and was valued at US$ 19 193–36 498 ha−1. The second park had no history of swine harvest and, over the monitoring period, damage escalated from 2.6%–6.4%, with an associated value of US$ 22 747–43 257 ha−1. Swine were managed as game animals in the third park prior to its inclusion into the state parks system in 2000. Within this park, the proportion of area damaged decreased from 4.3%–1.5%, valued at US$ 5 331–10 138 ha−1. This decrease may be a result of human activities associated with development of the park's infrastructure causing dispersal of animals conditioned to avoid humans by hunting. Damage was highly scattered in each park, as evidenced by a much higher proportion of sampling sites showing damage than the actual proportion of land area damaged. The dispersed nature of small amounts of damage would increase the effort required to recover habitat and thus damage value estimates are probably conservative. It was also impossible to incorporate values for such contingencies as swine impact to state and federally listed endangered plants in the parks, some of which are found nowhere else in the world.

The goal of this paper is to review current impacts of human activities on the deep-sea floor ecosystem, and to predict anthropogenic changes to this ecosystem by the year 2025. The deep-sea floor ecosystem is one of the largest on the planet, covering roughly 60% of the Earth's solid surface. Despite this vast size, our knowledge of the deep sea is poor relative to other marine ecosystems, and future human threats are difficult to predict. Low productivity, low physical energy, low biological rates, and the vastness of the soft-sediment deep sea create an unusual suite of conservation challenges relative to shallow water. The numerous, but widely spaced, island habitats of the deep ocean (for example seamounts, hydrothermal vents and submarine canyons) differ from typical deep-sea soft sediments in substrate type (hard) and levels of productivity (often high); these habitats will respond differently to anthropogenic impacts and climate change. The principal human threats to the deep sea are the disposal of wastes (structures, radioactive wastes, munitions and carbon dioxide), deep-sea fishing, oil and gas extraction, marine mineral extraction, and climate change. Current international regulations prohibit deep-sea dumping of structures, radioactive waste and munitions. Future disposal activities that could be significant by 2025 include deep-sea carbon-dioxide sequestration, sewage-sludge emplacement and dredge-spoil disposal. As fish stocks dwindle in the upper ocean, deep-sea fisheries are increasingly targeted. Most (perhaps all) of these deep-sea fisheries are not sustainable in the long term given current management practices; deep-sea fish are long-lived, slow growing and very slow to recruit in the face of sustained fishing pressure. Oil and gas exploitation has begun, and will continue, in deep water, creating significant localized impacts resulting mainly from accumulation of contaminated drill cuttings. Marine mineral extraction, in particular manganese nodule mining, represents one of the most significant conservation challenges in the deep sea. The vast spatial scales planned for nodule mining dwarf other potential direct human impacts. Nodule-mining disturbance will likely affect tens to hundreds of thousands of square kilometres with ecosystem recovery requiring many decades to millions of years (for nodule regrowth). Limited knowledge of the taxonomy, species structure, biogeography and basic natural history of deep-sea animals prevents accurate assessment of the risk of species extinctions from large-scale mining. While there are close linkages between benthic, pelagic and climatic processes, it is difficult to predict the impact of climate change on deep-sea benthic ecosystems; it is certain, however, that changes in primary production in surface waters will alter the standing stocks in the food-limited, deep-sea benthic. Long time-series studies from the abyssal North Pacific and North Atlantic suggest that even seemingly stable deep-sea ecosystems may exhibit change in key ecological parameters on decadal time scales. The causes of these decadal changes remain enigmatic. Compared to the rest of the planet, the bulk of the deep sea will probably remain relatively unimpacted by human activities and climate change in the year 2025. However, increased pressure on terrestrial resources will certainly lead to an expansion of direct human activities in the deep sea, and to direct and indirect environmental impacts. Because so little is known about this remote environment, the deep-sea ecosystem may well be substantially modified before its natural state is fully understood.

The deep sea is the world's largest ecosystem by volume and is assumed to have a high assimilative capacity. Natural events, such as the sinking of surface plant and animal material to the seabed, sediment slides, benthic storms and hydrothermal vents can contribute vast amounts of material, both organic and inorganic, to the deep ocean. In the past the deep sea has been used as a repository for sewage, dredge spoil and radioactive waste. In addition, there has been interest in the disposal of large man-made objects and, more recently, the disposal of industrially-produced carbon dioxide. Some of the materials disposed of in the deep sea may have natural analogues. This review examines natural processes in the deep sea including the vertical flux of organic material, turbidity currents and benthic storms, natural gas emissions, hydrothermal vents, natural radionuclides and rocky substrata, and compares them with anthropogenic input including sewage disposal, dredge spoil, carbon dioxide disposal, chemical contamination and the disposal of radioactive waste, wrecks and rigs. The comparison shows what are true analogues and what are false friends. Knowledge of the deep sea is fragmentary and much more needs to be known about this large, biologically-diverse system before any further consideration is given to its use in the disposal of waste.

River margins are valued for agriculture in the western Amazon because of their fertile soils and level surfaces. Riparian forests along river margins also provide valuable ecosystem services by protecting water quality and providing resources to aquatic organisms. Because inhabitants of the region rely on these aquatic resources, riparian deforestation may have unintended negative feedbacks on the health and well-being of rural communities. A survey of 79 households of mixed cultural background investigated how riparian environments were used, what mechanisms were in place for their conservation, and how local people valued them. Corn, beans and peanuts were cultivated preferentially in riparian areas, complementing the manioc and plantains grown on upland soils. People valued riparian areas for their ecosystem services and generally left a protective buffer of forest along rivers. Both the agricultural and ecological values of riparian areas may be preserved through proper management.

Mesoamerica (Southern Mexico, Guatemala, Belize, El Salvador, Honduras, Nicaragua, Costa Rica and Panama) is a culturally diverse region considered a conservation priority due to its biotic richness and high endemism. The Convention on Biological Diversity (CBD) sets out obligations and objectives for national parties to cope with biodiversity reduction, and encourages these national parties to develop measures to conserve and manage biodiversity. This paper presents trends in Mesoamerican countries in the implementation of the CBD, specifically in relation to the general measures for conservation and sustainable use (Article 6), identification and monitoring (Article 7), and in situ conservation (Article 8) derived from examination of reports from the CBD National Reports unit, questionnaires to national focal points, and interviews in the field. In general, there was increased effort toward CBD implementation and related issues. The scientific capacity, political stability, and accessibility to resources in each country, however, influenced the rate at which capacity was being built and the relative importance governments afforded to each of the CBD articles. Lack of resources or institutional limitations are identified as major impediments to fulfilling obligations. The CBD is also poorly known among actors in civil society and at several levels of administration. Overall, Costa Rica and Mexico are exceptions in the region with regard to inventory and monitoring, and the efforts to incorporate biodiversity into broader intersectoral policies. However, the measures required to ensure the fair and equitable sharing of benefits arising from biodiversity are poorly developed, or not developed at all, in the region. It is pivotal that, since Mesoamerica is one of the poorest regions in the world, any attempt to conserve biodiversity in the region must include sustainable use and equity.

Slash-and-burn is a widespread agricultural system practised by more than 250 million people in tropical regions. It is sustainable when fallow periods allow for the restoration of organic matter and nutrient losses that occur during the cropping phase. However, fallow periods have been reduced in most slash-and-burn systems as population density has increased. The consequent landscape structure modification occurring throughout this process can affect several ecological processes. As a first step in understanding these modifications, the present study aimed to test the effects of fallow period reduction on landscape structure by examining a total of 34 lots of 25–250 ha each in the north-east of the Brazilian Amazon. Sixteen lots with long fallow periods (about 10 years) were compared with 18 lots where fallow periods were reduced to c. four years. The reduction in fallow period created a more homogeneous landscape, largely dominated by agricultural and young secondary vegetation. The main mechanism leading to this homogenization was a more intensive use of initial secondary vegetation for agriculture. On average, the percentage of land used more intensively for agriculture was four times higher in short fallow period areas than in long-period areas. The increase in agricultural area is related to both an increase in the number of agricultural fields and also to an increase in the area of these fields. The proportions of forest and old secondary vegetation in the landscape were reduced as a consequence of a reduction in patch size, without significant fragmentation or patch losses. These structural changes appeared to be more usual in large properties belonging to several families. Further studies are needed to understand the consequences of these modifications for landscape functioning, but it is possible to speculate, based on previous studies, that these structural changes can lead to a reduction in the speed of regeneration processes.

Conservationists are missing opportunities to protect species at mass tourism sites where wildlife itself is not the main tourist attraction. At such locations are ‘incidental ecotourists’, i.e. tourists with multiple interests who encounter wildlife or fragile ecosystems inadvertently. A case study from Lamanai Archaeological Reserve, Belize, reveals the motivations of incidental ecotourists and their impact on an endangered primate species, the black howler monkey, Alouatta pigra. Four hundred and seventy-one visitors were surveyed to assess their travel goals, conservation commitments, and reactions to viewing howler monkeys. Data were also collected on the behaviour of tourists and monkeys during encounters. More intense tourist interactions with howler monkeys were correlated with the number of tourists and the duration of the encounter; guided parties interacted more intensely than unguided parties. Tourists were largely unaware that these interactions may harm the howler monkeys. Qualitative observations of howler response to tourists suggest short- and long-term negative impacts. These impacts could be mitigated through more effective guide training, limiting tourist group size, and increasing entrance fees at the Reserve. Improving environmental education may reduce impacts and motivate some tourists to become advocates for conservation of endangered species.

There is considerable interest in the fragmentation and loss of natural and semi-natural habitats, but few studies have examined the dynamics and mechanisms of change. A temporal analysis of landscape change on the South Downs in Sussex, UK, provides a clear description of the process of change over the 20 years 1971–1991. Transition probabilities were calculated from digital interpretations of an aerial photography time series of West Sussex. The analysis enabled quantitative comparison of landscape mosaics within different landscape ecoregions and under different management regimes to be made. Past changes in land use have produced a fragmented downland landscape. The key land conversion sequences identified show a substantial transition towards arable production, often at the expense of the internationally and nationally important unimproved grassland systems. A geographical information system facilitated greater understanding of the environmental and topographical characteristics of land converted to arable and other uses, and highlighted areas for protection and potential restoration. The patterns of land-use conversion observed in the study provide a landscape-scale planning tool for assessing the potential impact of agri-environmental policies, plans, and programmes in semi-natural grassland habitats.

Regional colleges in Tanzania, Cameroon and, recently, South Africa have trained some 4000 wildlife managers. Training need assessments called for major curriculum reforms, which were developed and implemented in the late 1990s. This is an analysis of the factors that influenced this curriculum reform in the colleges' endeavour to respond to new developments in African wildlife management. Since 1979, the curriculum of Garoua Wildlife College, Cameroon, has changed only gradually, whereas work placement subjects, selected by students and their employers, have quickly responded to developments in wildlife management, with an increase in the number of people-oriented subjects amongst other things. In the new curriculum, Garoua's mid-career students appreciated biology and inventory disciplines for their relevance, as well as courses in other disciplines tailored to conservation practice. The curriculum reforms implemented at Garoua depended on the presence of interested lecturers with an appropriate background, often obtained by additional training. The curricula of the regional wildlife colleges at Garoua (Cameroon) Mweka (Tanzania) and SAWC (South Africa) showed important differences, as a result of regional differences and differing visions of the wildlife management profession. All three colleges have struggled to establish a feedback system for continuous curriculum review. Increasing the exchanges between the colleges could further develop the curricula. While pursuing necessary changes in curriculum and institutions, care should be taken to avoid reducing the colleges' sustainability.

Contingent valuation (CV) is a popular method in economics for eliciting individuals' preferences for non-market environmental resources, but very few attempts have been made to apply it to distant environmental goods of global importance. This paper reports the results of a CV study in the UK and Italy, which evaluated non-users' willingness to pay for the implementation of a proposed programme of protected areas in Brazilian Amazonia. The main focus of the survey was the wealth of biodiversity in the region proposed for protection and the ecosystem services provided by such areas. Taking both countries together, respondents were willing to pay, on average, £30 (US$ 45.60) per household per annum to fund the implementation of a protection programme covering 5% of Brazilian Amazonia and £39 (US$ 59.28) per household per annum to fund a 20% programme. Aggregated across households, an annual fund to conserve 5% of Brazilian Amazonia as strictly protected areas could yield around £600 million (US$ 912 million) in the UK and a similar amount in Italy. It should be noted that respondents appeared to show a high degree of uncertainty in the bid decision process for such an unfamiliar and distant good, leading to questions as to the validity and reliability of results. Nevertheless, responses were non-random and systematically related to a range of socio-economic characteristics and attitudinal variables. Thus initiatives such as international financial transfers from wealthy developed countries to support the protection of threatened areas of global significance could attract widespread support in those countries.

In recent years, wildlife policies that consider the participation of stakeholders have been promoted. An understanding of the stakeholders' attitudes towards conservation and existing policies are critical in designing new policies or sustainable conservation strategies. This paper examines stakeholders' (local people, park staff and professional hunter guides) attitudes, towards the Bénoué Wildlife Conservation Area (BWCA) and towards Cameroonian wildlife policy. The BWCA encompasses the Bénoué National Park and its surrounding hunting concessions that also include some villages. Both the Park and the hunting concessions are two categories of protected areas. Data were collected using informal interviews and questionnaires administered to 114 households from three communities, 17 park staff and seven professional hunter guides. Local people's attitudes towards protected areas depended on the management category of the particular protected area. Local people were positive towards the existence of the Park, but negative towards the system of hunting concession areas. There was local variation between communities concerning these attitudes. Local people were generally positive to maintaining the present Park area, but preferred a reduction in the size of the hunting concessions. Both Park staff and professional hunter guides expressed concern about present management strategies and the extent of illegal resource exploitation. Despite having poor knowledge of the current Cameroonian wildlife policy, most of the local households expressed support for it, but called for increased local involvement in management, off-take and the harvesting of benefits from both Park and hunting concession activities. The Park staff were sceptical about local participation in this context and saw such endeavours as a threat to a sound biodiversity management scheme. The findings indicate the need to strengthen current wildlife policy, promote the involvement of local people and empower the Park staff, both in terms of resources and in terms of skills in interacting with local people. The revised policy should be designed so as to vary according to the category of protected area and allow site-specific adaptations. Local people must experience reduced incurred costs and increased incomes from the Park. An environmental education programme is recommended to extensively disseminate the policy to user groups in the area.

A method of environmental classification has been applied twice to surveys of the whole of England, Scotland and Wales (the United Kingdom). Such experience is now being extended to the European continent. The paper draws on the unpublished working-papers of the relevant scientists and institutions in reconstructing both the motives and circumstances in which a methodology was developed in the UK for the assessment of the ecological resources of the wider countryside. The principles of strategic classification and subsequent sampling from defined strata were initially devised for broadleaved woodland, and first tested at a regional level. They drew on classical regression theory, with the environmental classification being the independent, and the vegetation or habitat the dependent, variable. The approach was linked to the development of efficient algorithms for analysis and classification, and more recently remote sensing and geographical information systems. Successive Countryside Surveys of the UK, carried out since 1978, have provided an objective measurement of the decline in the quality of vegetation and habitats. Such a statistically robust approach can be used to measure the rates of vegetation and habitat change at the strategic European level, and as an aid to devising appropriate rural-resources policies.

Dehesas, rangelands occupied by scattered oak trees and characterized by silvopastoral uses, cover about 3.1 million ha in south-western Spain. There is considerable debate about the long-term persistence of holm oak (Quercus ilex) populations in dehesas, since most stands are overaged and seedlings and saplings are sparse. The forest cycle has been disrupted in most dehesas. Regeneration has been inhibited since stands were opened for agriculture and grazing. Oak diameters from three land-use groups (young dehesa [YD], middle-aged dehesa [MD], and old dehesa [OD]) in Cáceres Province, Spain, were compared. These groups differed in the age of the land-use system, i.e. time since the original Mediterranean forest was cleared. The dehesa systems were established about 80 (YD), 150 (MD) and 500 (OD) years ago. An analysis of 66 holm oak cross sections revealed a close correlation (r2 = 91.2%) between tree rings and diameters, so that diameter seems to be a reliable indicator of tree age. Nested analysis of variance showed significant variation in diameters between the land-use groups. There is generally a positive relationship between tree age and the age of agrosilvopastoral use of the dehesas. Sparse holm oaks in the dehesas are primarily remnants from the first forest cycle. Local differences in growth conditions (for example soil quality and tree density) contribute further significant diameter variation on a between-plot level. Diameter structure of abandoned dehesas showed two peaks and a high proportion of trees in the smallest size class. This indicates that the forest degradation process is reversible. An effective regeneration policy should promote a rotating 20- to 30-year set-aside of dehesa parcels.

Sacred groves, some as old as several centuries, may have contributed to the preservation of some plant species in Tanzania. This has led conservationists to consider whether sacred groves could be used for in situ conservation. Eight sacred groves of the Ugunda chieftaincy of the Wanyamwezi in central Tanzania representing burial sites that varied from 6–300 years old were inventoried to compare woody species richness and taxonomic diversity with those of forest plots in a state managed Forest Reserve. Although they occupied a relatively small area the sacred groves had greater woody species richness and taxonomic diversity than the state managed Forest Reserve. The forest plots and the groves shared a species similarity index of 45%, suggesting that the sacred groves contributed to in situ conservation of the miombo woodland biodiversity. Some of the woody species were absent in the forest plots, also suggesting that groves served as a refuge for some species. An inventory of all existing sacred groves could provide important information on their role in in situ conservation. In order to promote them for community-based conservation of biodiversity the government should declare sacred groves as preservation sites, and incorporate them into modern conservation systems.

There are many environmental and socio-economic concerns about the shrimp aquaculture industry. This study, based on interviews, direct observations and literature reviews, shows that the Indian hatchery industry is heavily dependent upon the continuous support of natural resources and ecosystem services generated by marine, freshwater and terrestrial ecosystems. The mangrove ecosystem support area (‘ecological footprint’) needed to supply the hatcheries with Penaeus monodon shrimp broodstock, and the aquaculture grow-out ponds with postlarvae, exemplify the dependence on external ecosystems. Each hectare of mangrove in the Godavari River delta generated an annual fisheries catch of 0.8–1.5 P. monodon spawners (gravid females), valued at US$ 92–184. The entire Godavari mangrove delta had a partial gross economic value of US$ 3.0–6.0 million per year for the provision of shrimp spawners alone. The average hatchery, producing 75 million postlarvae annually, had an ecological footprint of 534 ha mangrove for the life-support input of shrimp spawners. The ecological footprint of intensive shrimp ponds was up to 11 times the pond area for postlarval input alone. The shrimp ponds in the State of Andhra Pradesh needed 35 000–138 000 ha of mangroves to satisfy the spawner requirement to hatcheries, and this implied a need to appropriate mangroves in other regions. Hatcheries were prepared to pay up to US$ 2000 for a single shrimp spawner, which also illustrated that the mangrove support areas regionally available were too small. Other concerns about the industry are the net loss of employment if hatcheries replace wild postlarvae collection, the extensive use of groundwater creating direct resource-use conflicts, by-catch problems in broodstock fisheries, and pollution by effluents. The risk of hatcheries introducing, amplifying and propagating disease affecting both cultured organisms and wild biota is another concern that can, and should, be addressed.