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Viruses and nanbots

 * molecular robotics
 * Nanorobotics
 * Self-assembly of nanoparticles
 * Capsid

From: Virome:

Viromes were the first examples of shotgun community sequence, which is now known as metagenomics. In the 2000s, the Rohwer lab sequenced viromes from seawater, marine sediments, adult human stool, ...

T. Hinckley et al. Development of phage-based nanobots for the recognition, separation and detection of bacterial pathogens. 255th American Chemical Society National Meeting, New Orleans, March 20, 2018.

J. Chen et al. Lyophilized engineered phages for Escherichia coli detection in food matrices. ACS Sensors. Vol. 2. October 2017, p. 1573. doi: 10.1021/acssensors.7b00561

J. Chen et al. Bacteriophage-based nanoprobes for rapid bacteria separation. Nanoscale. Vol. 7. August 2015, p. 16230. doi: 10.1039/c5nr03779d

Breitbart, M; Felts, B; Kelley, S; Mahaffy, JM; Nulton, J; Salamon, P; Rohwer, F (22 March 2004). "Diversity and population structure of a near-shore marine-sediment viral community". Proceedings of the Royal Society B: Biological Sciences. 271 (1539): 565–74. doi:10.1098/rspb.2003.2628. PMC 1691639. PMID 15156913.

Rohwer, F. and Thurber, R.V., 2009. "Viruses manipulate the marine environment". Nature, 459(7244), p. 207.

Brussaard, C.P., Wilhelm, S.W., Thingstad, F., Weinbauer, M.G., Bratbak, G., Heldal, M., Kimmance, S.A., Middelboe, M., Nagasaki, K., Paul, J.H. and Schroeder, D.C., 2008. Global-scale processes with a nanoscale drive: the role of marine viruses". The ISME Journal, 2(6), p. 575.

Brum, J.R., Ignacio-Espinoza, J.C., Roux, S., Doulcier, G., Acinas, S.G., Alberti, A., Chaffron, S., Cruaud, C., De Vargas, C., Gasol, J.M. and Gorsky, G., 2015. Patterns and ecological drivers of ocean viral communities. Science, 348(6237), p. 1261498.  • "Ocean microbes produce half of the oxygen we breathe (1) and drive much of the substrate and redox transformations that fuel Earth’s ecosystems (2). However, they do so in a constantly evolving network of chemical, physical and biotic constraints – interactions which are only beginning to be explored. Marine viruses are presumably key players in these interactions (3, 4) as they affect microbial populations through lysis, reprogramming of host metabolism, and horizontal gene transfer"

Brum, J.R. and Sullivan, M.B., 2015. Rising to the challenge: accelerated pace of discovery transforms marine virology. Nature Reviews Microbiology, 13(3), p. 147. • "Marine viruses have important roles in microbial mortality, gene transfer, metabolic reprogramming and biogeochemical cycling" • "Viruses were once thought to have a limited influence in marine environments because initial studies detected few viruses capable of infecting cultivated bacteria1. However, similar to early studies of marine bacteria2 cultivation grossly underestimated marine viral abundance. In 1989, direct microscopic examination of seawater showed an ocean teeming with millions of viruses per milliliter of seawater1. Almost simultaneously, another study showed that viruses actively infect marine microorganisms3, which drive energy and nutrient transformations that fuel life on our planet4, leading to speculation that viruses have a major influence on marine ecosystem dynamics1,3 23 ." • "In summary, an explosion of novel tools, technologies and theories are transforming our conceptual view of marine viral ecology. Given this, and the experimental advantages of studying microbial systems, we further challenge the field to advance our understanding of ecological interactions of micro- and nano-scale entities to match, and perhaps even surpass, that of their macro-scale counterparts. " • "" • "" • "" ETC

Breitbart M (2012) Marine viruses: truth or dare. Ann Rev Mar Sci 4: 425–448.

Hemminga, M.A., Vos, W.L., Nazarov, P.V., Koehorst, R.B., Wolfs, C.J., Spruijt, R.B. and Stopar, D. (2010) "Viruses: incredible nanomachines. New advances with filamentous phages" European Biophysics Journal, 39(4): 541–550. • "From the perspective of nanotechnology, viruses can be regarded as efficient nanomachines, producing numerous copies of themselves."

Johnson, J.E. (2010) "Virus particle maturation: insights into elegantly programmed nanomachines". Current opinion in structural biology, 20(2): 210–216. • "Capsid maturation is an accessible natural example of a nano machine"

Koudelka, K.J., Pitek, A.S., Manchester, M. and Steinmetz, N.F. (2015) "Virus-based nanoparticles as versatile nanomachines". Annual review of virology, 2: 379–401. • "Nanoscale engineering is revolutionizing the way we prevent, detect, and treat diseases. Viruses have played a special role in these developments because they can function as prefabricated nanoscaffolds that have unique properties and are easily modified. The interiors of virus particles can encapsulate and protect sensitive compounds, while the exteriors can be altered to display large and small molecules in precisely defined arrays. These properties of viruses, along with their innate biocompatibility, have led to their development as actively targeted drug delivery systems that expand on and improve current pharmaceutical options." • "In contrast, bionanomaterials based on viruses allow for the templated assembly of millions of identical nanoparticles and their production in living cells. Viruses are ubiquitous in the environment, and those that infect bacteria, mammals, or plants have all been used to manufacture virus-based nanoparticles (VNPs). Viruses are an ideal starting point because they have evolved naturally to deliver nucleic acids and can therefore be subverted for the delivery of other molecules, such as drugs and imaging reagents. Finally, viruses replicate prodigiously, allowing the inexpensive manufacture of VNPs on an industrial scale." • "VNPs are high-precision materials that self-assemble into symmetrical and polyvalent structures that can be tailored at the atomic level. Virus-based materials come in a variety of shapes and sizes, but most are monodisperse with geometries that can be custom modified... Whereas some synthetic nanoparticles persist in the body for weeks or even longer (168–171), virus-based materials are subject to proteolytic degradation and thus are removed safely from the body within days"

Krupovic, M., Prangishvili, D., Hendrix, R.W. and Bamford, D.H. (2011) "Genomics of bacterial and archaeal viruses: dynamics within the prokaryotic virosphere". ''Microbiol. Mol. Biol. Rev.'', 75(4): 610–635. • "Over the past few years, the viruses of prokaryotes have been transformed in the view of microbiologists from simply being convenient experimental model systems into being a major component of the biosphere. They are the global champions of diversity, they constitute a majority of organisms on the planet, they have large roles in the planet’s ecosystems, they exert a significant—some would say dominant—force on the evolution of their bacterial and archaeal hosts, and they have been doing this for billions of years, possibly for as long as there have been cells."

Sunagawa, S., Coelho, L.P., Chaffron, S., Kultima, J.R., Labadie, K., Salazar, G., Djahanschiri, B., Zeller, G., Mende, D.R., Alberti, A. and Cornejo-Castillo, F.M., 2015. Structure and function of the global ocean microbiome. Science, 348(6237), p. 1261359.  • "We identify ocean microbial core functionality and reveal, given the physicochemical differences, a surprisingly high fraction of its abundance (>73%) to be shared with the human gut microbiome." • "Microorganisms are ubiquitous in the ocean environment, where they play key roles in biogeochemical processes, such as carbon and nutrient cycling (1). With an estimated 104 - 106 cells per milliliter, their biomass combined with high turnover rates and environmental complexity, provides the grounds for immense genetic diversity (2). These microorganisms, and the communities they form, drive and respond to changes in the environment, including climate change-associated shifts in temperature, carbon chemistry, nutrient and oxygen content, and alterations in ocean stratification and currents (3)."

Paez-Espino, D., Eloe-Fadrosh, E.A., Pavlopoulos, G.A., Thomas, A.D., Huntemann, M., Mikhailova, N., Rubin, E., Ivanova, N.N. and Kyrpides, N.C., 2016. Uncovering Earth’s virome. Nature, 536(7617), p. 425.  • "Viruses are the most abundant entities across all habitats, and a major reservoir of genetic diversity1 affecting biogeochemical cycles and ecosystem dynamics1. Exploration of viral populations in oceans of the world and within the human microbiome has illuminated considerable genetic complexity2,3"

Viruses as nanomachines

from: http://www.storagetwo.com/blog/2016/2/viruses-nanorobots-among-us Viruses defy the usual categories we use to define life. They don’t have cells. They don’t consume, store, or use energy. They don’t move. They don’t reproduce without a host. They don’t show any signs of activity at all unless they’re in an environment where they can spread. They have been compared to nanorobots, and in many ways, it is an apt description. If viruses are not “alive” as we define it, then what should we call these strange evolving and replicating entities?



Some phages "look just like lunar landers sent from alien spaceships", or as though they have been constructed by a child using an erector set. - Thinking Like a Phage: The Genius of the Viruses That Infect Bacteria and Archaea"Thinking Like a Phage", by Merry Youle.

Doubtful marine viruses could infect humans since viruses need to be sensitively tuned to the target host, which in this case is not present in the ocean

From Virus: Viruses display a wide diversity of shapes and sizes, called morphologies. In general, viruses are much smaller than bacteria. Most viruses that have been studied have a diameter between 20 and 300 nanometres. Some filoviruses have a total length of up to 1400 nm; their diameters are only about 80 nm. Most viruses cannot be seen with an optical microscope so scanning and transmission electron microscopes are used to visualise them.

From Virus: Viruses are by far the most abundant biological entities on Earth and they outnumber all the others put together. They infect all types of cellular life including animals, plants, bacteria and fungi. Different types of viruses can infect only a limited range of hosts and many are species-specific. Some, such as smallpox virus for example, can infect only one species—in this case humans, and are said to have a narrow host range. Other viruses, such as rabies virus, can infect different species of mammals and are said to have a broad range. The viruses that infect plants are harmless to animals, and most viruses that infect other animals are harmless to humans.

"The marine environment is primarily occupied by microbes, mainly bacteria and protists, which account for about 70% of the total marine biomass."


 * earth's total biomass is 560 billion tonnes.
 * Cyanophage
 * Microbial ecology

Middelboe, M. and Brussaard, C. (2017) "Marine viruses: key players in marine ecosystems". Viruses. 9(10): 302.


 * Giant virus


 * virophages

Paez-Espino, D., Eloe-Fadrosh, E.A., Pavlopoulos, G.A., Thomas, A.D., Huntemann, M., Mikhailova, N., Rubin, E., Ivanova, N.N. and Kyrpides, N.C. (2016) "Uncovering Earth’s virome". Nature, 536(7617): 425. 

Freshwater fish of New Zealand



 * Birds of New Zealand
 * List of birds of New Zealand

"Native freshwater fishes of New Zealand. The fauna is sparse (~ 40 species) and characterised by a high degree of diadromy... this fauna offered an opportunity to 'explore pattern and process, cause and effect, evolution and biogeography,in a way that would have been much more difficult in areas with more speciose faunas'... The family Galaxiidae comprises a group of southern hemisphere fishes whose wide geographic range and the diversity of habitats they have colonised are somewhat akin to the northern hemisphere salmonids... studying the ecology of the migrations of juvenile galaxiids (known locally as 'whitebait', and considered a delicacy)"

"At present, 50 genetically distinct, extant fish species are recognised in freshwaters in New Zealand with another three or four species yet to be formally named (Allibone et al. 2010) (Table 1). However, the actual species number is hard to define because eight are classified as ‘freshwater indeterminate’: they are essentially marine species but move far into fresh waters for long periods. Only one native fish, the endemic grayling (Prototroctes oxyrhynchus), is known to have become extinct since the first human settlement of New Zealand c. 700 years ago, although many other species have become locally extinct over much of their pre-European range. New Zealand’s freshwater fish fauna is unique, with 92% of the named species found nowhere else in the world."

"Diadromy: One feature of the New Zealand freshwater fish fauna is the large proportion of diadromous species: namely, fish that undertake two migratory movements between the ocean and fresh water in their life cycles. Diadromous fish employ three very distinctly different strategies: anadromy, catadromy, and amphidromy (Table 3). Anadromous fish spend their adult life in the sea, move to fresh water to breed, then die; catadromy is essentially the opposite, with fish spending most of their adult life in fresh water before a final migration to the ocean to breed and die; and amphidromy is an intermediate strategy in which adults live in fresh water, usually breed yearly, and the juveniles spend time in the ocean before returning to fresh water (McDowall 1988). A few decades ago diadromy was thought to be obligatory in most diadromous species, but we now know that in some species diadromy seems to be facultative, as not all individuals migrate. In the currently recognised extant taxa, diadromy is thought to be obligatory in 13 species and facultative in 6, and at least one diadromous species is present in each of the nine families in the New Zealand fauna (Ling 2010). Seven diadromous species include landlocked populations, usually, but not always, are formed when a lake outlet is blocked (Closs et al. 2003)"

Overview
"Compared to other countries, New Zealand has a sparse freshwater fish fauna of just over fifty species. But it is unique and comprises at least thirty-five native species of which thirty-one are found only in New Zealand. Most of the native species belong to just four families of fish, and include twenty galaxiids, seven bullies, two eels, and two smelts. Nine potentially new galaxiid species have been recently found in Otago but are yet to be named so the list is not yet complete."

"Because of the sparse native fish fauna, a large number of species have been introduced (legally, illegally and accidently). Of the fifteen species that are known to have established breeding populations in more than one location, six are salmonids (Salmonidae), four are cyprinids (cyprinidae), and three are live-bearers (Poecillidae). The redfin perch and the bullhead catfish are also well established. A further two species (grass and silver carp) are present, but do not breed. Five other species have very restricted populations and their current status is uncertain."

"An unusually high proportion of the native fish are diadromous (i.e. they all have a marine phase in their lifecycle). Although several grow to adulthood in freshwater then migrate downriver to breed in the sea (e.g., eels, mullet, freshwater flounder), most breed in freshwater with their juveniles travelling downriver to develop at sea (e.g., galaxiids, smelt and bullies). Only the lamprey breeds and develops in freshwater streams and spends its entire adult life at sea."

"Because these diadromous species all need to migrate upriver from the sea at some stage, they are vulnerable to barriers created by falls, chutes, dams, weirs, and culverts. They also vary widely in their ability to move upriver. Some species (eels and certain galaxiids) can climb vertical wet rock faces and they penetrate far upriver to high altitudes. Others cannot climb and are restricted to lowland, coastal streams. As a consequence, the geographical distributions of the species vary widely within rivers and are greatly affected by both altitude and distance from the sea."

"Many of the native species are small, cryptic and/or are nocturnal so it is not surprising that most people are not aware that they are present. They express surprise when they learn that there is more to the native fauna than just eels and galaxiids. For example, redfin bullies are brightly coloured and good in aquaria, whereas torrent fish are shaped like a stealth fighter and are well adapted to cope with the high water velocities found in rapids where they live."

"Many of the largest native galaxiids (called kokopu) live mostly in small streams running beneath forest or bush canopies. Widespread conversion of forest to pasture has resulted in their decline, and the introduction of predatory trout restricts their distributions within forested streams. As a consequence of these changes, together with the creation of migration barriers and loss of habitats, a number of the native fish are now endangered. A 2010 report indicated that whereas only the grayling is extinct, eight species are nationally threatened and another twelve are now in decline."

"Eels and galaxiids are responsible for commercial and cultural fisheries in New Zealand rivers with five species of galaxiids comprising the national delicacy known as 'whitebait'. Sports fisheries are based on introduced species, including chinook salmon (South Island rivers), rainbow and brown trout (lakes and rivers nationally), and coarse fish (perch, rudd, tench, koi carp), mainly in small North Island lakes. Other introduced species (i.e., gambusia, catfish, goldfish) have few if any values and some of the introduced species are pests in some places because they either reduce native biodiversity, degrade other species habitats, or contribute to the decline of water quality in lakes."

Native species
"The latest information indicates that New Zealand has around 40 native species of freshwater fish. This count may increase as new genetic techniques bring a better understanding of the diversity within some fish groups. Thirty-three species are known only in New Zealand. Kōaro, longfin eels and spotted eels are also found in Australia, while lamprey and īnanga also occur in Australia, Chile and Argentina. New Zealand’s native freshwater fish belong to eight distinct families: the jawless lamprey, eels, smelts, southern graylings, galaxiids, torrentfish, bullies and flounder. Most are relatively small, although the eels are an obvious exception – some female longfin eels are up to 2 metres long and 25 kilograms in weight."

Age
"Longfin eels are the longest-living native fish, generally taking 20–30 years to reach maturity. Some large female eels stay in fresh water for over 80 years. In contrast, smaller species, such as īnanga, reach maturity in just one year and rarely live longer than three years."

Diet
"Almost all native fish prey on invertebrates or other fish. However, historical accounts indicate that the now-extinct grayling (Prototroctes oxyrhynchus) was an exception and grazed on algae from river rocks."

Migration and life cycles
"Nearly half the native fish species migrate to and from the sea during their life cycle. As not all species can climb rapids and waterfalls, freshwater fish are most diverse at low altitudes, closer to the coast.
 * Lampreys reproduce in fresh water but develop mostly at sea.
 * Eels reproduce at sea, but most of their growth occurs in fresh waters.
 * The five species of galaxiids that form the whitebait catch lay their eggs in fresh water, but their larvae quickly migrate to sea and spend a few months there before heading back to fresh water."

Distribution
"Although not found elsewhere, many of New Zealand’s freshwater fish do have close relatives in Australia, South America and Southern Africa. Two species that do exist beyond New Zealand are lampreys and īnanga. This distribution, with other evidence, indicates that migration across the oceans is an important factor explaining the global spread of these fish."

Factors affecting life in fresh water
"A range of factors influence the types of species that live in different parts of New Zealand.
 * At a broad level, evolutionary history and climate determine which species are found in certain regions.
 * At a finer level, factors such as water quality, land use, channel shape, or lake type influence the range of species found in a river reach or lake.
 * Small-scale factors (light and food availability, cover, predation, competition, water depth and speed) also control which species live at certain sites within a river or lake. All these factors can interact to shape freshwater ecosystems."

Light availability
"Without light, plants cannot grow. There are big differences between the communities living in the well-lit surface and edges of lakes, and those in the depths, which receive little or no light. Turbid (muddy) water also restricts the amount of light that reaches the bed. Lakes with large shallow areas tend to be more productive than lakes with little shallow water (because more light reaches the lake bed). A similar situation exists in river systems, where heavily shaded streams rely on leaves and other organic material from the surrounding catchment to fuel the ecosystem. In larger rivers the canopy opens up, allowing algal production to become more important."

Predators versus available food
"There is debate about whether the number of invertebrates (insects and other animals without backbones) in a habitat is controlled by the number of predators that will eat them, or by the amount of food available for them. Both factors are important, but their relative importance may vary. For example, the introduction of trout appears to have changed some streams from systems controlled by the available food to those controlled by trout as predators."

Disturbances: floods and droughts
"Rivers and streams are particularly prone to disturbance, due to huge changes in flows, as in floods and droughts. Although these are often seen as harmful, it appears that a moderate level of disturbance can promote higher diversity in some systems. This makes sense: if there is some variation in an environment, more life forms may be able to live there."

Human impact
"Irrigation and hydroelectricity projects. Water is currently in high demand, and the value of freshwater systems is often weighed against the potential value of using the water. Hydroelectric dams and large irrigation projects can turn running waters into lakes, affect water quality, and restrict fish movement along river systems."

Farming
"Many rivers and lakes now have high concentrations of nutrients, sediment and faecal bacteria, and problems with algal blooms (a heavy growth of algae). This is because more intense farming leads to excessive runoff of sediment and fertilisers into waterways. Taking water for irrigation has also harmed the water quality of lowland streams and some lakes. The Rotorua lakes are classic examples. Too many nutrients enter the lakes, causing algal blooms, which in turn starve the water of oxygen. At times, the lakes are closed for swimming, due to low water quality."

Pests
"Various pests have become established in freshwater systems. Pest fish prey on native species and can stir up mud and alter the water quality. Invasive aquatic plants grow profusely, changing the habitat and causing problems for recreational activities. For example the introduced weed Lagarosiphon major can grow so profusely that it clogs the shoreline, making it unattractive for swimming. Even tiny algae can cause problems. In 2004 outbreaks of Didymosphenia geminata smothered South Island riverbeds, affecting everything living there."

Where are the fish?
"New Zealand has an abundance of cool clear rivers, streams and lakes, but if you look into the water you will not usually see many fish. The journals of many early settlers refer to empty rivers. Believing there were no native fish, they introduced trout and salmon – species that would meet their expectations as game and a source of food. But it was a mistake to think the rivers were empty, as Māori had long caught a wide variety of native fish. European settlers soon discovered the delight of fresh whitebait, and learned to fish for upokororo (grayling). As Māori knew well, eels were a nutritious addition, and livened up an often plain colonial diet. Many New Zealanders are surprised to learn that fisheries biologists recognise more than 40 native freshwater fish species. If asked about freshwater fish, most people will mention trout (which are not native), eels, and perhaps whitebait. There is little awareness of the variety of native fish in rivers and lakes."

Ousted by trout
"New Zealanders are more familiar with trout and salmon than with native fish. Trout and salmon were introduced in the late 19th and early 20th centuries. Massive trout populations rapidly developed, with adverse effects on native fish through predation, competition for food and displacement from favoured habitats."

Secretive and nocturnal
"For some reason that scientists do not understand, nearly all native freshwater fish are very furtive creatures. By day they typically live among boulders and pebbles of streams and lake beds, or hide beneath overhanging stream banks, or among logs and woody debris. Most species are also quite small. New Zealand’s eels are nocturnal, as are many other native freshwater fish. An effective, low-tech way of identifying fish, especially in small streams, is spotlighting – shining a broad-beamed torch into a stream at night to see what is out and about."

Small streams
"The greatest diversity of native fish occurs in small streams – many of them no more than a metre wide. It is not clear why they prefer this habitat. It could be partly because introduced trout have forced them into smaller headwater streams, preying on them or displacing them from their habitats. It is likely that there are other reasons as well."

Protection
"Freshwater fish are not protected under the Wildlife Act 1953, although native fish are protected in national parks or other conservation lands. For many species, legal protection from being caught is not really an issue as land use and developments that damage their habitats pose far greater threats to their survival. There are some regulations to manage the harvest of eels, whitebait, smelt and lamprey that form small fisheries."

Geography
"New Zealand’s freshwater fish have strong connections with fish of other southern lands. The shortfin eel, īnanga and kōaro are found in eastern Australia, and īnanga in Patagonian South America and the Falkland Islands. In the past some researchers suggested that this spread was because New Zealand, like Australia, was once part of the supercontinent Gondwana. Recent DNA research indicates that it is far more likely that these fish are more recent arrivals, carried around the southern hemisphere on oceanic currents. Some endemic groups such as the pencil galaxias may have an ancient Gondwana heritage."

Evolving from marine species
"Some species that evolved as marine fish have established themselves in fresh water. Just how this happens is unknown, but at some stage an event must have caused a shift into fresh water. Perhaps a lack of fish diversity in river rapids provided an opportunity for a marine species to invade this environment. The torrentfish still retains its marine connections by living at sea during larval and early juvenile life. The black flounder must still return to sea for spawning and early juvenile life. Several flounder (mainly marine) can also live in river estuaries and lowland lakes. But the black flounder has taken the process a little further – it may be found many kilometres up some rivers."

Links to the sea
"Nearly half the native freshwater species are found in the sea at some life stage. This may be as larvae and juveniles (as with whitebait species and several bullies), after which they return to fresh water. Some adults (such as eels) may migrate to sea to spawn. In another example, the smelts living in rivers spend most of their lives at sea before returning to fresh water as adults, to spawn. Fish migrate between rivers and the sea at most times of the year, but especially in spring and autumn. These species are known as diadromous (from Greek words meaning ‘running across’)."

Climbing
"The distribution of the migratory species depends on how far upstream they can move. Rapids and waterfalls are not necessarily barriers. Some species have extraordinary climbing abilities, and can be found upstream of waterfalls tens of metres high. Eels are able to climb like this, and some of the whitebait species, especially kōaro, banded kōkopu and shortjaw kōkopu. These fish climb mostly when small, moving up the wet margins of falls, and using their fins to hold onto rocks by surface adhesion. Some are well known for climbing out of buckets, and if in captivity, often climb out of aquariums (they can climb glass as long as it is damp)."

Stuck in the Nevis
"For the past half million years Otago’s Nevis River has flowed north into the Kawarau River, which then flows into the Clutha River. But it is thought that the Nevis once flowed south, into Southland’s Mataura River. Supporting evidence is that the Nevis has a Galaxiid species (Galaxias gollumoides) that is otherwise found only in the Mataura and other Southland waterways. The fish is found only in one other isolated locality in the Clutha catchment."

Flexible behaviour
"Many species can vary their behaviour. Although the ancestral pattern is for them to go to sea, they can establish landlocked populations in the open water of lakes rather than the sea – mostly at the juvenile stage."

Nocturnal activity
"A high number of native species are nocturnal, moving from under cover to be active at night. Why they are so nocturnal is not understood. The most likely explanation is that it might minimise predation by aquatic birds, especially shags, and perhaps herons. But if it is an avoidance strategy then a paradox emerges. Some fish are habitual prey for large eels, which are also more active at night, emerging from cover to feed."

Galaxiids


"Most native freshwater fish species are called galaxiids (from the family name Galaxiidae). There are seven genera in the family and two (Galaxias and Neochanna) occur in New Zealand. The name refers to their profusion of small, silvery-gold spots, which were compared to the stars in a galaxy by those who first identified them... In New Zealand there are at least 25 species in this family. New species are still being discovered, with eight recognised since the early 1990s. Galaxiids are a fascinatingly diverse group. Most are shy creatures that few people ever see. A small number of enthusiasts find them appealing and keep them in captivity... Galaxiids have no scales, and their dorsal fin lies toward the rear of the body. The main fins form a propulsion unit towards the tail, making them adept at rapid acceleration and short bursts of speed, though not so well designed for long-distance swimming."

"The galaxioid fishes are the dominant, most speciose group of freshwater fishes (with >50 species) in the lands of the cool southern hemisphere, with representatives in western and eastern Australia, Tasmania, New Caledonia, Lord Howe Island, New Zealand, the Chatham, Auckland and Campbell Islands, Patagonian South America (Chile, Argentina), the Falkland Islands and South Africa. The group is most diverse in Australia and New Zealand. Lepidogalaxiidae is found only in Australia, Retropinnidae in Australia and New Zealand, and Galaxiidae across the entire range of the group. Many species are in serious conservation crisis for a diversity of reasons, including habitat deterioration and possibly fisheries exploitation, but there is enduring and pervasive information that shows that the group has been seriously impacted by the acclimatisation of salmonid fishes originating in the cool-temperate northern hemisphere, particularly brown and rainbow trout. With few exceptions, where these trout have been introduced there has been major decline in the galaxioids, especially Galaxiidae, as a result of a complexly interacting series of adverse impacts from these introduced fishes. In some places, centrarchids and cichlids may also have adverse impacts. In addition, there appear to have been adverse impacts from the translocation of galaxioids into communities where they do not naturally occur. In many instances it appears that displacement of the galaxioids has led to a situation where galaxioids and salmonids no longer co-occur, owing either to displacement or predation, leading to fish communities in which there is no explicit evidence for displacement. These effects are resulting in the galaxioid fishes being amongst the most seriously threatened fishes known."

Kōaro relatives
"There is a group of species that are closely related to the kōaro. Scientists are beginning to discover these highly secretive fish in the headwaters of streams in the eastern and southern South Island. Although very similar to the kōaro, they do not have larvae that go to sea. They spawn in spring. Over spring and summer small shoals of whitebait-like juveniles appear in pools and backwaters. They live in open water for several months and grow to about 4 centimetres long, when they disappear into gravels of stream beds and are rarely seen."
 * taxonomically uncertain

Mudfish (Neochanna)
"Also belonging to the galaxiid family are the Neochanna mudfishes. These are specialised for living in wetlands and swampy spring heads. Best described as cigar-shaped, some may be up to 15 centimetres long. Of five species, three have completely lost their pelvic fins (fins under the body about halfway back to the tail), and in the others these are much reduced. Using their dorsal and anal fins, and well-adapted broad, rounded tails, they swim among the debris of bush wetlands. They are known for their ability to aestivate – spend summer in a state of semi-torpor, surviving if water disappears. Mudfish can survive a long drought. When their wetlands dry out in summer, they find cavities and objects to lie under, breathing air through their skin. As the autumn rains fill the wetlands, the fish are washed out again."

Smelt
"New Zealand has two fish of the Retropinnidae family. These are the common smelt (Retropinna retropinna) and Stokell’s smelt (Stokellia anisodon). Although smelt have a very strong cucumber odour when they are first captured, the name smelt has nothing to do with this. It is an ancient word for silvery – referring to their colour. Growing to around 10 centimetres, smelt move into lowland rivers from the sea as mature adults to spawn – often being caught towards the end of the whitebait fishing season, in spring. They are very fragile, dying within a minute or two if handled. The smelt populations in some inland lakes, especially in the central North Island, belong to the same species, but have abandoned migrations to and from the sea, spending their whole lives in fresh water."

Links

 * Freshwater fish Department of Conservation,Wellington.
 * NIWA Atlas of NZ Freshwater Fishes NIWA.

Eels
"Freshwater eels are fish, and belong to the family Anguillidae. Slow growing and long lived, they begin life in the sea, and then spend many years in fresh water as adults. Finally they return to sea to spawn, after which they die. Many people are scared of eels, because they are snakelike and slimy, and can slither over land. There are very few reports of eels attacking, but if they do, their teeth can grip. In one incident a longfin eel bit the wetsuit of a diver, who had to use a knife to release its hold. Unlike nearly all other freshwater fish, eels have a long cylindrical shape, and continuous dorsal (back), caudal (tail) and anal fins. They have pectoral (side) fins but no pelvic fins. Covered in a layer of mucus, eels are extremely slippery. Although they seem to lack scales, under the microscope you can see a mosaic of tiny scales in the leathery, slimy skin. Eels can travel over land, slithering through wet grass to get to a pond or lake. As long as their skin stays moist they can absorb oxygen through it, surviving long periods out of water. Freshwater eels are found worldwide. Of 15 recognised species, most occur in the waterways that flow into western Pacific and Indian oceans. There are none that spawn in the eastern Pacific or the South Atlantic."

New Zealand eels
"Eels are New Zealand’s top native freshwater predators – no other species prey on them when they are adult. Māori identified many different varieties, mainly by colour. But when European settlers first arrived in New Zealand there was debate about the number of species. There are three species, all from the Anguillidae family of fish: The longfin and shortfin eels are found all around New Zealand. They have very varied coloration, so this is not the best way to identify them. The most reliable distinguishing feature is the length of the back fin – hence their names."
 * longfin eel (Anguilla dieffenbachii), found further inland
 * shortfin eel (A. australis), found on the coast
 * spotted eel (A. reinhardtii), which may have recently arrived from Australia and is found only in northern rivers.

Spotted eel
"The spotted eel also occurs in eastern Australia, New Caledonia and Lord Howe Island. It was first confirmed in New Zealand waters in 1997, and is currently only found in rivers from Taranaki to Northland. It has a distinctive colour pattern – mottled or blotched on the back, with yellowish pectoral fins. This eel grows to 1.5 metres and 14 kilograms. The maximum reported age is 41 years."

"Diet and feeding: Eels were once considered a threat because they ate introduced trout. But they are now economically important in New Zealand, and there has been considerable research into their diet. Big longfin eels may eat species such as juvenile trout – larger prey than that of the shortfin or spotted eel. One 9-kilogram eel was reported to have eaten an entire shoveller duck. Small (less than 50-centimetre) longfin and shortfin eels generally feed on snails, insects, worms, grubs, crayfish and small fish. Eels feed mainly at night, using their powerful sense of smell to track prey. Once an eel is close, taste buds on its head and sensors along its sides help locate the victim."

"The largest recorded longfin eel is a 24-kilo specimen taken from Lake Waihola, south of Dunedin, in 1974. At Lake Ellesmere (Te Waihora) in Canterbury, shortfin eels longer than 50 centimetres increasingly become fish-eaters, preying on cockabullies and smelt. Feeding drops off during winter in both species, especially in southern New Zealand. Growth rates are slow. Longfin eels grow at around 2.5 centimetres a year at a length of 30 centimetres, and they slow down to only 1.5 centimetres a year at a length of 1 metre. Shortfin eels grow a little faster. These slow rates are a result of temperature, food supply and competition. Faster growth rates have been achieved in trials to fatten eels in farm ponds."

Life cycle


"Freshwater eels have a remarkable life cycle, which begins and ends in the ocean. Spawning has never been observed. Adult eels probably spawn at some depth in warm seas. New Zealand’s shortfin eels produce 1.5–3 million eggs, and the longfins 1–20 million eggs. Males fertilise the eggs. After spawning, the adults die.cFertilised eggs hatch at the surface and become leaf-shaped larvae, floating on ocean currents towards the coast. They have teeth, but it is not clear for what purpose – they may store calcium for bone development. Their skin may absorb nutrients, as researchers have not found food in the larvae.cOnce the larvae reach land, an extraordinary transformation takes place: they become slender, transparent eels, known as glass eels. They arrive at New Zealand’s coast from July to December, with numbers peaking in spring (August–October) – the time of whitebait migration. Glass eels migrate into river mouths or estuaries in astounding numbers.cHydroelectric dams are an obstacle to elvers (young eels) swimming upriver. Some dams have special passes, allowing them to get round the massive concrete walls. But they don’t always need this help. Elvers can climb the 43-metre Arapuni Dam on the Waikato River, and the 75-metre Patea River dam in Taranaki. Glass eels soon turn grey-brown, and in this form they are known as elvers. They migrate upriver, often in swarms and usually at night. Young elvers can climb waterfalls, but lose this skill as they grow. Elvers become adults, with bigger heads and fatter bodies. After many years in fresh water, eels migrate back down the waterways to the sea. It is thought that males fertilise the eggs once the females spawn out at sea. When they reach breeding size, eels change from ‘yellow-bellies’ to ‘silver-bellies’. The yellow-grey underside becomes grey-white, the head shape changes and the head, back and pectoral fins darken."

"Shortfin males migrate in February–March, and longfin males in April. The females soon follow, and both males and females die after spawning. Studies show the species also migrate at different ages: Shortfin males at an average of 14 years (38–58 centimetres), females at 22 years (50–100 centimetres). Longfin males an average of 23 years (48–74 centimetres), females at 34 years (75–180 centimetres). It is not known how long the journey takes. One female longfin eel that was tagged took 161 days to swim from Canterbury’s Lake Ellesmere (Te Waihora) to a point 160 kilometres north-east of New Caledonia. Barriers across waterways have hampered their route. One estimate suggests that hydroelectric dams have blocked the longfin eel’s access to the sea in 35% of its habitat."

"For centuries, larval eels were thought to be a separate species: they occur in the ocean and look different from adult, freshwater eels. Then in 1896 the Italian zoologist Giovanni Grassi reported that Leptocephalus brevirostris, known as a saltwater fish, was in fact the larva of the European freshwater eel. But just where at sea they bred was a mystery. Searching for breeding grounds: In a 1923 paper, Danish biologist Johannes Schmidt stated that American and European eels spawned in the Sargasso Sea, in the Atlantic. In 1926, after sailing his research vessel Dana II to Australia and New Zealand, he concluded that New Zealand eels probably bred somewhere east of New Caledonia. But the exact locations are still not fully known."

"Longfin eels: At migration, longfin eels are more ready to reproduce than shortfin eels. Scientists thought this meant their spawning grounds were closer to shore. However, a study showed that the longfin eel had the longest larval stage of any Pacific freshwater eel reported. This suggests that the larvae actually hatch further away from New Zealand, possibly near Tonga. They were also the biggest specimens when they reached coastal waters – so they may have been at sea longer, and travelled further."

Export and fishery management
"Freshwater eels have become an important export, often live or as processed products. They go mainly to South-East Asia, Europe and Canada. Annual sales ranged from $800,000 to $3.5 million between 1990 and 2004. Live eels and products such as smoked fillets, whole smoked eels or skinned segments are available from local processors and restaurants. Worldwide, eel production is declining because of overfishing of glass eels (juveniles) and adults, and damage to the environment. Many countries farm eels, usually sourced from wild glass eels. International demand for wild glass eels for use in eel farms is strong. The market is subject to fluctuations, and high prices can be paid. Through the Quota Management System the New Zealand government controls and monitors commercial fishing, limiting the total catch to ensure sustainability."

"In 2000, the South Island’s shortfin and longfin eels came under the quota system. Both species were treated as a single stock. In 2004 the North Island eel fisheries were included, but the two species were managed separately. Treating South Island shortfin and longfin eel fisheries as a single stock is questionable. Longfin eels breed later in their lives than shortfin eels, which makes them more vulnerable to overfishing."

Links

 * Eel: New Zealand freshwater fish Department of Conservation.
 * Keeping tabs on our native eels
 * The long and the short of it: looking after native eels NIWA.

Overview
"In, ecology, and status of New Zealand's freshwater Fisheries resources are reviewed. Rivers are the main freshwater features in these Pacific temperate-zone islands. Geological events, the islands' remoteness, and the recent nature of human colonization (first Maori and then European) have shaped the freshwater ichthyofauna. Diadromy is a dominant ecological feature for many indigenous species. Many species have also been introduced to create Fisheries. Traditional Maori Fisheries are focussed on indigenous eels and whitebait while recreational Fisheries target introduced salmonids. Management of New Zealand freshwater Fish is dispersed among several departments. New Zealand habitats are pristine by global standards due largely to the recent settlement of European colonists. Many rivers have been impounded for electricity generation; this constitutes the main environmental issue for freshwater Fish. Intensification of agriculture also poses a growing eutrophication threat. The ecologies of indigenous species are becoming better known but much knowledge is anecdotal. Efforts to conserve indigenous freshwater species are increasing. Impoundment, irrigation, deforestation, and introduced salmonids, are the main threats to the native fauna."

New Zealand whitebait
"74 per cent of the country's native freshwater fish are now listed as threatened. Dr Joy said that was up on 68 per cent in 2009 and 30 per cent at the first review in 1992. New Zealand's figures were worse than any other country that kept such measurements. The global average was 35 to 37 per cent threatened. Dr Joy said native freshwater fish were like miner's canaries measuring the health of rivers."

"Many New Zealanders consider whitebait a delicacy, with its sweet, tender flavour. Often lightly cooked in fritters, the tiny fish are eaten head and all. They fetch a high price in the netting season... In their juvenile form, īnanga are well known as the chief species in the whitebait fishery, which is made up of juvenile fish of five different Galaxias species".

About 90% of the whitebait is made up of juvenile īnanga 

Links

 * McDowall, R. M. (1996). Managing the New Zealand whitebait fishery: a critical review of the role and performance of the Department of Conservation. NIWA Science and Technology Series No. 32. ISBN 047808370X.
 * Eikaas, H. S. (2004). The effect of habitat fragmentation on New Zealand native fish: a GIS approach. PhD thesis, University of Canterbury.
 * Haggerty, J. H. (2007). “I’m not a greenie but…”: Environmentality, eco-populism and governance in New Zealand Experiences from the Southland whitebait fishery. Journal of rural studies, 23(2), 222-237.
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 * Urgent review of whitebait rules needed Taranaki Daily News, 26 August 2015.
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 * Cobden restoration group
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 * Videos
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 * misc
 * Tempero, G. W., Ling, N., Hicks, B. J., & Osborne, M. W. (2006). Age composition, growth, and reproduction of koi carp (Cyprinus carpio) in the lower Waikato region, New Zealand. New Zealand Journal of Marine and Freshwater Research, 40(4), 571-583.

Biogeography
"New Zealand has been isolated in the southwestern Pacific Ocean since it separated from Gondwana during the Cretaceous period, some 80 million years ago. This prolonged geological isolation, combined with the islands’ very vigorous geological history, impacted by oceanic submergence, tectonic activity, mountain building extreme volcanism, and great climatic variability, create a dynamic scenario within which the New Zealand biota, including its freshwater fishes, have evolved over millions of years. These impacts have contributed to a highly dynamic biological history with undoubted though little understood extinction and vigorous colonisation of the islands’ fresh water. One of the key elements for understanding the origins and derivations of this fish fauna is that in all groups some or all of the species are diadromous, customarily spending a significant phase of their lives at sea. This has no doubt contributed in an important way the fauna’s origins as well, there has been frequent loss of diadromous behaviours leading, to species that have abandoned their sea-migratory behaviours and which now complete their entire lives in fresh water. The distribution patterns reflect these changing habits, with diadromous species being broadly distributed but tending to be lowland in range, whereas the derived, non-diadromous species have narrower ranges, but are often found further inland and at high elevations."

According to McDowall, New Zealand has a biota that" has broad relationships, primarily around the cool Southern Hemisphere, as well as with New Caledonia to the north. There are hints of ancient Gondwanan taxa, although the long-argued predominance of taxa derived by vicariant processes, driven by plate tectonics and the fragmentation of Gondwana, is no longer accepted as a principal explanation of the biota’s origins and relationships... Most of the terrestrial New Zealand flora and fauna has clearly arrived in New Zealand much more recently than the postulated separation of New Zealand from Gondwana, dated at c. 80 Ma. There is a view that New Zealand may have disappeared completely beneath the sea in the early Cenozoic, and acceptance of this would mean derivation of the entire biota by transoceanic dispersal. However, there are elements in the biota that seem to have broad distributions that date back to Gondwanan times, and also some that are thought unlikely to have been able to disperse to New Zealand across ocean gaps, especially freshwater organisms. Very strong connections to the biota of Australia, rather than to South America, are inconsistent with the timing of New Zealand’s ancient and early separation from Gondwana and seem likely to have resulted from dispersal."

Dispersal biogeography
"The broad distribution of freshwater fishes of the lamprey families Geotriidae and Mordaciidae and the salmoniform Galaxiidae and Retropinnidae in the southern cool temperate zone, has caused prolonged perplexity and debate. Arguments in favour of both a dispersal biogeography and a Gondwana-based vicariance biogeography have been presented. These are not necessarily alternatives. Main conclusions – Evidence from: all support, or are consistent with, a dispersal biogeography of this southern cool temperate fauna. The groups involved are sufficiently ancient to have formerly inhabited Gondwana, but no compelling evidence indicates that present distributions reflect a former broad Gondwana-based range. A role for dispersal in these fishes is consistent with increasingly common claims for dispersal in other taxa. This does not mean that there was no ancient influence from Gondwanan vicariance."
 * Distribution patterns in relation to life-history strategies;
 * Genetics and morphology;
 * Different elements in the New Zealand fauna and their relationships;
 * Recent dispersal events;
 * Geological history of the Falkland Islands and the relationships of its freshwater fishes; and
 * Parasitology;

Other references
34 (1): 185–194.
 * Allibone, R., David, B., Hitchmough, R., Jellyman, D., Ling, N., Ravenscroft, P., & Waters, J. (2010). "Conservation status of New Zealand freshwater fish" New Zealand Journal of Marine and Freshwater Research, 44 (4): 271–287.
 * Goodman, J. M., Dunn, N. R., Ravenscroft, P. J., Allibone, R. M., Boubee, J. A., David, B. O., ... & Rolfe, J. R. (2014). "Conservation status of New Zealand freshwater fish, 2013" New Zealand Threat Classification Series, series 7, New Zealand Department of Conservation. ISBN 9780478150148.
 * McDowall, R.M. (2010) New Zealand Freshwater Fishes: an Historical and Ecological Biogeography Springer. ISBN 9789048192717.
 * McDowall, R. M. (2010) "Historical and ecological context, pattern and process, in the derivation of New Zealand’s freshwater fish fauna" New Zealand Journal of Ecology, 34: 185–194.
 * McDowall, Robert M. (2010) Historical and ecological context, pattern and process, in the derivation of New Zealand’s freshwater fish fauna New Zealand Journal of Ecology,


 * McDowall, R. M. and Whitaker A.H. (2012) |%22freshwater+fishes%22+%22new+Zealand%22&source=gbs_toc_r&cad=4#v=onepage&q=Biogeography%20%22freshwater%20fish%22|%22freshwater%20fishes%22%20%22new%20Zealand%22&f=false "The freshwater fishes" In: G. Kuschel (Ed) Biogeography and Ecology in New Zealand, pp. 277–286. Springer Science. ISBN 9789401019415.


 * Berra, T. M., Crowley, L. E. L. M., Ivantsoff, W., & Fuerst, P. A. (1996). "Galaxias maculatus: an explanation of its biogeography Marine and Freshwater Research, 47 (6): 845–849. Full text
 * Elston E, Anderson-Lederer R, Death RG and Joy MK (2015) The Plight of New Zealand’s Freshwater Biodiversity Conservation Science Statement No. 1. Society for Conservation Biology (Oceania).
 * Jellyman, P. G., & Harding, J. S. (2012). The role of dams in altering freshwater fish communities in New Zealand. New Zealand Journal of Marine and Freshwater Research, 46(4), 475-489.
 * Joy, M. K., & Death, R. G. (2013). "Freshwater biodiversity" Ecosystem Services In New Zealand, Manaaki Whenua Press, Lincoln, New Zealand.
 * Weeks, E., Kingsford, R. T., Taylor, A., & Joy, M. (2014). Protecting the future of New Zealand’s freshwater ecosystems.
 * McDowall, Bob . Freshwater fish Te Ara - the Encyclopedia of New Zealand, updated 9-Jul-13.

Taxonomically undetermined species (14)
"Fourteen native entities are listed as taxonomically indeterminate and are awaiting formal description.

Introduced and naturalised species (20)
Defined by the Department of Conservation as "taxa that have become naturalised in the wild after being deliberately or accidentally introduced into New Zealand by human agency".

20 species

Introduced fish
"In the late 1800s and early 1900s, British settlers introduced fish of the Salmonidae family – trout and salmon – to New Zealand. Some of these species now form important recreational fisheries. Less well known, and usually much less widespread, are 15 other introduced species. These are known as coarse fish – many have coarser scales than trout and salmon."

Trout and salmon
"From the late 1800s, British settlers introduced fish of the Salmonidae family – trout and salmon – to New Zealand. Many species were released, yet only three established themselves well enough to form important fisheries: brown trout, rainbow trout and Chinook salmon. European settlers brought trout and salmon to New Zealand’s lakes and rivers so they could fish them for sport. The most common species today are brown trout, rainbow trout and Chinook salmon."

Sea-going trout
"In the late 1800s and early 1900s it was thought that sea trout were a different species from riverine trout. But it has long been known that some brown trout live in estuaries and also go out to sea. Today it is accepted that riverine and sea trout are merely variants of brown trout. Brown trout’s colours can change depending upon the waterway they live in. Sea-run trout can be a bright silvery colour, brown trout from rivers tend to be golden brown, and those from lakes are a duller silver. All have black spots, and riverine browns also have red spots."

Taupō trout
"Soon after they were brought to New Zealand, rainbow trout grew very large in Lake Taupō, but then declined in size. The average weight of trout in one angler’s bag was 10½ pounds (4.8 kilograms) in 1911, but by 1918 it had dwindled to 4 pounds (1.8 kilograms). The early bonanza was probably due to the trout feeding on the then plentiful native fish."

Chinook salmon life cycle
"Life cycle: Females and males pair up and the female digs a depression in a gravel stream bed and lays eggs. The male deposits his milt to fertilise them. Eggs hatch into alevins (fry with yolk sacs attached) in spring. After the yolk sac is used up, the fry emerge from river gravels in streams that they use for spawning. They spend about three months swimming downstream, entering the ocean in summer. In the sea the young salmon feed on small fish and crustaceans, and grow rapidly into adults. At maturity (3–4 years) they swim upstream in ‘runs’ or large numbers to spawn in the upper reaches of rivers. After spawning all adults die. The size of salmon runs changes from year to year. The best river was the Waitaki, but much of its glory was lost after the government built a dam at Kurow in 1935 – greatly reducing the size of the salmon run from perhaps 100,000 fish to 10,000. A fish ladder was built up the side of the dam but it was poorly designed and never worked. In the 2000s, upriver runs consist of a few thousand fish in each of the main rivers. Anglers probably catch 35–40% of them. In any given year the total run has varied between 10,000 and 75,000 fish – most years being at the lower end. Hatcheries: attempts to raise numbers' The variability of salmon runs led to efforts to enhance the size by hatching and releasing young salmon. In Canterbury, wild salmon were trapped and stripped of ova in spawning streams. During the 1980s, fish reared in hatcheries on the Rakaia River increased the size of runs. But the cost per fish reared was too high, and runs were still variable."

"There were also plans for "ocean ranching" – commercialising the fishery – in the 1970s and 1980s. The theory was that hundreds of thousands of salmon would be hatched from ova and released. They would go to sea and feed at no cost and come back as adults to be harvested. The plans went ahead and the salmon were released, but they did not come back. In the 2000s commercial salmon farms operated at South Island freshwater sites such as Waikoropupū Springs near Tākaka, and the Tekapo canal in the Mackenzie country. But most farmed salmon were reared in sea cages in the Marlborough Sounds and Stewart Island."

"The average survival rate for smolt [young salmon migrating to the sea] is less than one per cent, and anglers catch about a third of the returning fish, so for every salmon caught you have to release 300 smolt. To significantly improve the number of returning salmon you’d have to annually release 300,000 to 500,000 smolt, and they cost a dollar each to rear. This means each fish costs between $300 and $500."

"Research suggests that conditions out at sea may determine the number of salmon that return. Conditions in the rivers are also a factor. In spring and summer, juvenile salmon make their way downriver to the sea. Floods can kill juveniles or wash them out to sea. Stable flows give them a chance to stay longer in the river and so reach a greater size by the time they go to sea. Those that get to sea at three months of age make up 75% of returning adults."

Other salmonids
"In the late 1800s and early 1900s attempts were made to introduce other salmonid species such as whitefish, Atlantic salmon, brook char and mackinaw – but with little success."

"Whitefish (Coregonus clupeaformis): Much effort went into acclimatising this species, native to high-latitude lakes in the northern hemisphere. From 1876 to 1907 nearly 10 million ova were brought in. Some whitefish were hatched and released into lakes, but the species never became established."

Other reading

 * Fishing in New Zealand
 * NIWA Atlas of NZ Freshwater Fishes
 * Hayes, John, and Les Hill. The artful science of trout fishing. Christchurch: Canterbury University Press, 2005.
 * Millichamp, Ross. Salmon fever: a guide to salmon fishing in New Zealand. Christchurch: Shoal Bay, 1997.
 * McDowall, R. M. The Reed field guide to New Zealand freshwater fishes. Auckland: Reed, 2000.

Coarse fish
"Coarse fish are freshwater fish other than trout or salmon. They are called coarse fish because their scales are usually larger and coarser than those of trout or salmon. They were introduced in the late 1800s and early 1900s by British settlers, for aquariums or fishing. Many have been illegally set free by anglers wanting to stock up rivers and lakes.

Types of coarse fish
"Coarse fish found in New Zealand are: Most belong to Cyprinidae, a family which contains almost 2,500 species, including carps, minnows, and a host of other small fish found across Europe, Asia, Africa and North America."
 * Cyprinidae family – goldfish, koi carp, tench, rudd, orfe, gudgeon, grass carp, silver carp
 * Poeciliidae family – gambusia, caudo, common guppy, sailfin molly, swordtail
 * Percidae family – European perch
 * Ictaluridae family – brown bullhead catfish.

Coarse fishing
"Coarse fish are caught by anglers with a baited hook attached to a float. Some species have been illegally introduced and spread by anglers wanting to fish for them. Some species such as goldfish are usually too small to be targeted by anglers. Some very keen coarse anglers aim to catch a variety of species or the largest fish species. A few species, including silver carp and grass carp, do not breed naturally in New Zealand waterways and populations are maintained by releasing fish reared in captivity. It is doubtful whether some species, such as caudo, are established at all, despite records of their presence in New Zealand."

Legal status
"Introduced fish can have four statuses under various pieces of legislation: Offenders can attract a maximum sentence of five years and/or a fine of up to $100,000. The legal status of some species varies. For example, rudd is only a ‘sports fish’ in the Auckland–Waikato fish and game region, but a ‘noxious fish’ elsewhere. Some species, such as caudo, goldfish and orfe, have no legal status."
 * sports fish (e.g. perch, tench) – it is an offence to fish for them without a licence.
 * noxious fish (e.g. koi carp, rudd) – illegal to possess, breed or release under the Freshwater Fisheries Regulations 1987.
 * unwanted organism (e.g. koi carp, gambusia) – illegal to release, spread, sell or breed under the Biosecurity Act 1993.
 * restricted species (e.g. silver carp, grass carp) – releases require the approval of the minister of conservation.

Value or pest?
"Some coarse fish are valued as food (European perch), or for recreational angling (European perch, koi carp, rudd, tench). Some have adverse effects on ecosystems (koi carp, rudd, tench, gambusia), while others are valued for their use in biological control (grass carp and silver carp). When ‘noxious fish’ or ‘unwanted organisms’ are found in contained areas such as ponds or small lakes, authorities sometimes eradicate them using the natural toxin rotenone, known as Derris Dust to gardeners."

Morihana on horseback
"Sub-inspector Morrison of the Armed Constabulary released goldfish into Lake Taupō in 1873, after bringing the fish on horseback from Napier. Goldfish became known to Māori as morihana – a transliteration of Morrison’s name. For some time morihana were a food for Rotorua Māori."

Robert (Bob) McDowall

 * Robert (Bob) McDowall 1939–2011
 * Jellyman, D. (2002). "Bob McDowall—his contribution to New Zealand's freshwater fish" New Zealand Journal of Marine and Freshwater Research, 36: 1–12.
 * Jellyman, Don J. (2011) Robert M. McDowall—taxonomist and biogeographer Environmental Biology of Fishes, 92 (4): 425–435.
 * Jellyman, D. J. (2011). "Robert M. McDowall—taxonomist and biogeographer". Environmental Biology of Fishes, 92 (4): 425–435. Full text
 * Robert Montgomery McDowall Obituary, The Royal Society of New Zealand, 14 March 2013.
 * Bob McDowall – his contribution to freshwater fish and fisheries of New Zealand and Australia – Don Jellyman
 * Watershed book from freshwater fisheries expert NIWA

New Zealand dairy farming

 * Foote, K. J., Joy, M. K., & Death, R. G. (2015). "New Zealand Dairy Farming: Milking Our Environment for All Its Worth" Environmental management, 56 (3): 1–12. Full text

Focus

 * Planetary boundaries
 * Bounding the Planetary Future: Why We Need a Great Transition Johan Rockström, Great Transition Initiative
 * 4. Steffen, Will et al. (2015) "The trajectory of the Anthropocene: The Great Acceleration." The Anthropocene Review 2053019614564785.


 * The Great Acceleration
 * Planetary Boundaries 2: The Great Acceleration - Interview with Katherine Richardson, 15 January 2015.
 * Visualizing the "Great Acceleration": The IGBP's Planetary Dashboard 9 Febuary 2015.
 * Great Transition
 * Anthropocene


 * Animal consciousness
 * animals have consciousness? ScienceLine, 6 March 1015. New York University.


 * Swarm intelligence
 * Talk:Swarm intelligence

Fish intelligence

 * Fish intelligence
 * Cognition
 * Intelligence
 * Bird intelligence
 * Cat intelligence
 * Cephalopod intelligence
 * Cetacean intelligence
 * Dinosaur intelligence
 * Evolution of human intelligence
 * Grubb TC (2003) The Mind of the Trout: A Cognitive Ecology for Biologists and Anglers Univerity of Wisconsin Press. ISBN 9780299183745.
 * fish "small brain" Google search
 * fish "small brain" Google Scholar
 * The Mind-Reading Salmon: The True Meaning of Statistical Significance Charles Seife, Scientific American, 12 August 2011.

Fish hold the records for the relative brain weights of vertebrates. Most vertebrate species have brains that weigh about the same in proportion to their total body mass. The deep sea bathopelagic cusk-eel Acanthonus armatus, is an ambush predator with a huge head. This fish has the smallest relative brain of all known vertebrates. At the other extreme, the elephantnose fish, an African freshwater fish, has the largest relative brain of all known vertebrates.

Goldfish can be trained to recognize and to react to light signals of different colors by using positive reinforcement. Goldfish have a memory-span of at least three months and can distinguish between different shapes, colours and sounds. Another experiment demonstrated retention of more than 1 month. Fish respond to certain colors most evidently in relation to feeding. Fish learn to anticipate feedings provided they occur at around the same time everyday. Goldfish can learn tricks, such as the limbo, slalom, fetch and soccer, using positive reinforcement training techniques.
 * from goldfish:


 * intelligence


 * fish are sentient

From : A recent issue of Fish and Fisheries, devoted to learning, cited more than 500 research papers on fish intelligence, proving that fish are smart, that they can use tools, and that they have impressive long-term memories and sophisticated social structures. The introductory chapter said that fish are "steeped in social intelligence, pursuing Machiavellian strategies of manipulation, punishment and reconciliation … exhibiting stable cultural traditions and cooperating to inspect predators and catch food."

• Culum Brown, a University of Edinburgh biologist who is studying the evolution of cognition in fish, says, "Fish are more intelligent than they appear. In many areas, such as memory, their cognitive powers match or exceed those of 'higher' vertebrates, including non-human primates." Their long-term memories help fish keep track of complex social relationships. Their spatial memory—"equal in all respects to any other vertebrate"—allows them to create cognitive maps that guide them through their watery homes, using cues such as polarized light, sounds, smells, and visual landmarks.

• Dr. Phil Gee, a psychologist from the University of Plymouth, says that fish can tell what time of day it is, and he trained fish to collect food by pressing a lever at specific times. He says "fish have a memory span of at least three months," and they "are probably able to adapt to changes in their circumstances, like any other small animals and birds."

• "We're now finding that [fish] are very capable of learning and remembering, and possess a range of cognitive skills that would surprise many people." —Dr. Theresa Burt de Perera, Oxford University

• A scientific review presented to the Australian Veterinary Association completely disproved the old myth that goldfish have three-second memories; instead, the veterinarians found that goldfish have impressive memories and problem-solving abilities. One of the researchers said that after conducting the review, they wanted “to get the message out to vets to start looking more closely at fish and considering their welfare like they do other animals.” —The Sunday Times, May 28, 2006

• "Australian crimson spotted rainbowfish, which learnt to escape from a net in their tank, remembered how they did it 11 months later. This is equivalent to a human recalling a lesson learnt 40 years ago." —Sunday Telegraph, Oct. 3, 2004


 * memory


 * collective intelligence
 * swarm intelligence
 * Swarm intelligence of fish schools
 * Migratory Behavior




 * 
 * neurons in a fish
 * Scientists Capture All The Neurons Firing Across A Fish's Brain On Video Popular Science, 19 March 2013.
 * Swarm intelligence of fish schools
 * Cooperation in Fishes
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"Machiavellian Intelligence hypothesis" fish


 * Scientists highlight fish 'intelligence' BBC, 31 August 2003.


 * video
 * Dr Culum Brown-Expert on fish behaviour, intelligence and memory – ABC.