Osmeriformes

(Smelts, galaxiids, and relatives)

Class Actinopterygii

Order Osmeriformes

Number of families 9

Evolution and systematics

Fossil Osmeriformes include Speirsaenigma lindoei, the oldest fossil osmerid from the Paleocene formations of Alberta, Canada, and a presumed close relative of the ayu (Plecoglossus altivelis; suborder Osmeroidei), Enoplophthalmus (Osmeroidei) from Europe, and possibly the family Pattersonellidae within the Argentinoidei.

The systematics of the "lower" euteleosts, particularly the Protacanthopterygii (the pikes, salmons, and smelts), has been in a constant state of flux since about the middle of the 1970s. Many phylogenies developed since that time considered that the Protacanthopterygii included three main lineages, one that included the pikes, pickerels, and mudminnows (Esociformes), another including the salmons, trouts, chars, graylings, and whitefishes (Salmoniformes), and a third comprising the freshwater and diadromous smelts, the galaxiids, the southern graylings, the marine argentines, deepsea smelts, barreleyes, and slickheads (Osmeriformes). The ancestor of the remaining teleosts, the "higher teleosts," or the Neoteleosti, is thought to be either the common ancestor of the Protacanthopterygii and the Neoteleosti, or to have risen within the Protacanthopterygii (Johnson and Patterson, 1996). However, many researchers did not necessarily formally recognize any of the above groups at the order level. Furthermore, the precise relationships of the various members of these groups has been a source of constant debate among ichthyologists researching the "lower" euteleosts (Johnson and Patterson [1996], as well as Rosen [1974], Fink [1984], Nelson [1994], and Begle [1991 and 1992]), who base their research primarily on anatomical and morphological data, and the most extensive study utilizing molecular data of Waters et al. (2000).

In light of the lack of consensus among these studies, it seems prudent, for the time being at least, to retain the traditional groupings/orders of the Esociformes, Salmoniformes, and Osmeriformes, while modifying them slightly to take into account the thorough studies of Johnson and Patterson (1996) and Waters et al. (2000). Such a scheme has been used in this chapter. However, it is likely that, with the collection of additional molecular data from a suite of taxa that represents all the major groupings, a further revision to the classification of the "lower" euteleostean fishes will occur.

If the classification given above is accepted, the Osmeriformes contains two suborders, the Osmeroidei (the smelts, galaxiids, etc.), which includes four families and approximately 70 species, and the Argentinoidei (the argentines, deepsea smelts, etc.), which includes five families and approximately 170 species. Just as it is likely that changes to the classification of this group will occur with the collection of more data, so it is also likely that the number of species will increase.

The nine families of Osmeriformes are: smelts (Osmeridae); salamanderfishes (Lepidogalaxiidae); New Zealand smelts or southern graylings (Retropinnidae); galaxiids or southern minnows (Galaxiidae); Argentines or herring smelts (Argentinidae); barreleyes or spookfishes (Opisthoproctidae); deepsea smelts (Microstomatidae); tube shoulders (Platytroctidae); and deepsea slickheads or slickheads (Alepocephalidae).

Physical characteristics

Morphological characteristics that are unique to, and present in, all members of the Osmeriformes have not yet been determined, and this is reflected in the placement of the group and its constituent members at different taxonomic levels by many researchers, including Fink (1984), Eschmeyer (1990), Johnson and Patterson (1996), and Helfman et al. (1997).

It is often stated that members of this group are generally silvery and elongate fishes. However, this probably reflects the fact that most authors are more familiar with the Northern Hemisphere species of the family Osmeridae (smelts) than with other groups. For example, even though members of the Southern Hemisphere families Galaxiidae and Lepidogalaxiidae are generally elongate, only a few have a silvery belly and none could be considered silvery overall, the majority having a brownish or olive base color overlaid with stripes, spots, or mottling of various colors. In addition, although many Argentinidae possess silvery sides, many species found in the other families of the suborder Argentinoidei, and in particular those that inhabit the deep oceans, are black or brown in color. In regard to shape, most members of the order are elongate, but the Opisthoproctidae (barreleyes) are often deep bodied and laterally compressed.

Members of the Osmeriformes are usually very small to small fishes, ranging in size from 1.2 to 27.5 in (3–70 cm);0.0016 oz to 3 lb (0.22 g–1.3 kg). The maximum length recorded for the eastern Australian galaxiid (Galaxiella pusilla) is only 1.5 in (3.9 cm), and the mean length of males and females at maturity is only 0.9 and 1.1 in (2.4 and 2.8 cm), respectively. However, some representatives of the argentines (Argentinidae) and slickheads (Alepocephalidae) may reach considerably larger sizes than the diminutive eastern Australian galaxiid, including the slickhead (Alepocephalus rostratus) of the western Mediterranean and eastern Atlantic, which attains a length of at least 27.5 in (70 cm).

There are several physical characteristics of the major groups of Osmeriformes that help to distinguish them. Helfman noted that Osmeriformes have a single dorsal fin made up of soft rays, have abdominal pelvic fins, often have an adipose fin, and generally have a toothless maxilla. The smelts (super-family Osmeroidea) are typical osmeriforms, in that they are elongate fishes with bright silvery scales, and have a dorsal fin situated toward the center of body, as well an adipose fin and a forked caudal fin. In most species, fingerlike filaments rising from the pyloric region of the stomach (pyloric ceca) are present, these structures aid digestion. Although most osmeroids are covered with bright silvery scales, others, such as the ayu (subfamily Plecoglossinae) are olive dorsolaterally and white ventrally. An adhesive membrane that acts as an anchoring mechanism surrounds the eggs of all members of the Osmeroida, and several species smell of cucumber instead of fish.

In contrast to the predominantly silvery Osmeroidea, fishes in the super-family Galaxioidea (galaxiids and relatives) often have a brown-to-olive base color overlaid with stripes, bands, or spots of various colors. Although members of the Retropinnidae and some species of the Galaxiidae, i.e., the single species Lovettia sealii (Tasmanian whitebait), and both species of Aplochiton, have an adipose fin and a deeply forked caudal fin, the other galaxiids and the salamanderfish (Lepidogalaxias salamandroides) have no adipose fin and a truncate or rounded caudal. Pyloric ceca are present in both species of Aplochiton and some other members of the Galaxiidae. The majority of the Galaxiidae are scaleless.

Like the Osmeroidea, most members of the super-family Argentinoidea (argentines, deepsea smelts, and relatives) are generally silvery, and have a dorsal fin situated toward the middle of the body and a forked caudal fin. Although some species within the Microstomatidae and the Bathylagidae (deepsea smelts) possess an adipose fin, others do not. Most members of this group have small mouths with no teeth on the upper jaw. As is the case with many fishes that are nocturnal or inhabit deep waters, many members of the super-families Argentinoidea and Alepocephaloidea (slickheads and relatives) have very large eyes, an adaptation that maximizes the collection of the little light available in poorly lit waters.

Unlike the other marine, and often deep-sea, members of the Osmeriformes, such as the Argentinoidea, the Alepocephaloidea are generally black/brown in color, have a dorsal fin situated toward the back of the body, do not possess an adipose fin, and generally have large mouths that, except for the three species of Leptochilichthyes, have teeth on the upper jaw.

Sexual dimorphism has been recorded in some members of the osmeriforms. For example, female salamanderfish attain lengths of over 2.7 in (7 cm), but the males are much smaller and have never been recorded at lengths greater than 2 in (5 cm). Furthermore, the males develop a series of enlarged scales, or a scale sheath, around their anal fin, which is absent in females. Males of many osmerids develop tubercles during the breeding season. In addition to exhibiting sexual dimorphism with regard to differences in size, some osmeriforms develop nuptial coloration. For example, during the breeding season, some galaxiids become particularly brightly colored. The black-stripe minnow (Galaxiella nigrostriata) develops a bright orange to vermillion lateral stripe, which is often highlighted by the development of dark brown to black stripes on either side.

Distribution

The first suborder of the Osmeriformes, the Osmeroidei (smelts, galaxiids, etc.), is restricted to latitudes north and south of the tropics. Within this suborder, those taxa that constitute the super-family Osmeroidea are, with the notable exception of some members of the tribe Salangini (icefishes and noodle-fishes), restricted to the cooler regions of the Northern Hemisphere. The Osmeroidea have a wide distribution, occurring in the Arctic, Atlantic and Pacific Oceans, as well as the rivers that drain into these oceans. However, they are absent from the Indian Ocean and its drainages, presumably a reflection of the fact that the vast majority of species comprising this super-family occur in cool temperate waters. They are also absent from the Mediterranean and its drainages. The tribe Osmerini (smelts) has a circumpolar distribution, with representatives in the Arctic, Atlantic, and particularly the Pacific Oceans, but the ranges of the Plecoglossinae (the ayu, or sweetfish) and the Salangini are far more restricted; both these groups are found only in the coastal waters and drainages of the eastern Pacific. However, while the Plecoglossinae and the Salangini do not occur in the Arctic or Atlantic Oceans or their drainages, their extension into the lower latitudes is far greater than any other member of the Osmeroidei. For example, the Plecoglossinae, represented solely by the ayu, has a range that extends from northern China to Korea and Taiwan in the south; the Salangini, represented by 11 species, has a range that that has a similar northern extent of its range but extends into Vietnam.

In contrast to the Northern Hemisphere Osmeroidea, the three families in the super-family Galaxioidea are found only in the Southern Hemisphere. The most widespread family is the Galaxiidae, representatives of which are found in Australia (where 22 of the 35 species occur), Lord Howe Island, New Caledonia, Tasmania, Chile, Argentina, and the tip of South Africa. Two of the remaining three families, the Retropinnidae and Prototroctidae, are found in Australia and New Zealand. Two species of the Retropinnidae, the Australian smelt (Retropinna semoni) and the Tasmanian smelt (Retropinna tasmanica), together have an extensive range that encompasses much of subtropical and temperate eastern Australia. The cucumberfish (Retropinna retropinna) and Stokell's smelt (Stokellia anisodon) are found in New Zealand. The Prototroctidae are represented in Australia by a single species, the Australian grayling, found in the coastal streams of New South Wales, Victoria, and Tasmania. The New Zealand grayling (Prototroctes oxyrhynchus) was last recorded in the 1920s. The third family of Southern Hemisphere Osmeroidei, Lepidogalaxiidae, consists of the single species, the salamanderfish, which is confined to the acid/peat flat region of the southwestern tip of Western Australia.

In contrast to the suborder Osmeroidei, whose members occur in fresh or coastal marine waters and essentially have a holarctic distribution, the obligate marine members of the suborder Argentinoidei can be found in all ocean waters from the Arctic in the north, through the Atlantic, Indian, and Pacific Oceans (including tropical and equatorial regions), to the southern ocean around Antarctica in the south. Species of the family Opisthoproctidae, subfamily Microstomatinae, are found in tropical to temperate regions of the Atlantic, Indian, and Pacific Oceans. Fishes in the subfamily Bathylaginae are represented in the subarctic to Antarctic, Atlantic, Indian, and Pacific Oceans; members of the family Argentinidae are found throughout Atlantic, Indian, and Pacific waters; and members of the families Platytroctidae and Alepocephalidae are found in all oceans.

Habitat

Osmeriforms are found in most aquatic habitats, in fresh waters in torrential mountain streams, slow-flowing rivers, ponds, lakes, and even pools that become completely dry for several months of the year, to highly variable salinity of estuaries, out into shallow inshore marine habitats, and on to the meso-and bathypelagic regions of the open ocean (deeper than 9,840 ft/3,000 m). Thus, with the exception of the freshwater systems of the lower latitudes of the Americas, Africa, the Indian subcontinent, and Australia, members of this order may be found in marine and freshwater environments off or in all of the continents. Furthermore, in the more temperate regions of the Southern Hemisphere, they are likely to be encountered in any aquatic habitat that fish biologists sample.

For example, in the fresh waters of Australia, species such as the Australian grayling and the climbing galaxias (Galaxias brevipinnis) tend to be restricted to the upper reaches of river systems, where they are found in shady areas over a rocky substrate in clear waters of moderate-to fast-flowing tributary streams. Other species, such as the barred galaxias (Galaxias fuscus), although also restricted to the headwaters of river systems, appear to prefer the slower-flowing pools below riffles and rapids. Further downstream, species such as the Australian smelt and the trout minnow (Galaxias truttaceus) tend to be found in the still to slow-flowing backwaters of streams and rivers, and to lakes and swamps, where they are found amid vegetation, logs, rocks, and other structure around the margins. Other species of Southern Hemisphere osmeriforms, such as swan galaxias (Galaxias fontanus), Clarence galaxias (Galaxias johnstoni), and Pedder galaxias (Galaxias pedderensis) are most commonly found in lakes and pools; Tasmanian mudfish (Galaxias cleaveri) and swamp galaxias (Galaxias parvus) occur in muddy marshes and swamps; and black-stripe minnow and salamanderfish inhabit small tannin-stained and acidic pools that often become completely dry in summer. Other Southern Hemisphere forms, such as the western minnow (Galaxias occidentalis), are found in all the above habitats, as well as in many of the brackish, salt-affected, streams, rivers, and lakes that are unfortunately becoming more common in southwestern Australia. Some populations of trout minnow and common jollytail (Galaxias maculatus) spend their adult lives in rivers and lakes, but move down into the brackish areas of estuaries to spawn. The larvae then move out to sea, where they spend the first year of life before moving back into rivers as juveniles.

In the Northern Hemisphere, most osmeriforms in fresh waters are usually anadromous forms on their annual spawning run, however, some species, such as the rainbow smelt (Osmerus mordax) of North America and ayu of Asia, have both anadromous or amphidromous and freshwater populations. Freshwater populations of both these species tend to spend their adult life in lakes.

As with the freshwater osmeriforms, the marine forms also occur in a wide range of marine habitats. The majority of the anadromous, amphidromous, and strictly marine Osmeroidea, such as the capelin (Mallotus villosus), are found in the shallow coastal waters out to the continental shelf, while members of the super-family Argentinoidei are found in these waters and also out over the continental shelf and into the open ocean. Although representatives of the Argentinoidei occur in all major habitats of the open ocean, only one species of the family Alepocephalidae, Microphotolepis schmidti, is known to inhabit the epipelagic zone (the top 656 ft/200 m of the water column). However, the Argentinoidei is well represented in the deeper zones of the open oceans. For example, in the Western Central Pacific Ocean (based on the FAO designation), Nansenia ardesiaca, Nansenia pelagica, and Xenophthalmichthys (subfamily Microstomatinae); Bathylagus nigrigenys and Dolicholagus longirostris (longsnout blackmelt, subfamily Bathylaginae); and Dolichopteryx longipes, Opisthoproctus grimaldii, Opisthoproctus soleatus, and Winteria telescopa (family Opisthoproctidae), are meso-to bathypelagic, meaning that they live in open waters above the bottom at depths of 656–13,120 ft (200–4,000 m). In the same region, Argentina spp. and Glossanodon struhsakeri (family Argentinidae) are benthopelagic, living on and just above the bottom, on the outer continental shelf and slopes to depths of about 4,590 ft (1,400 m). Approximately 59 species of the family Alepocephalidae and approximately 21 species of the family Platytroctidae are found above the continental shelf and ocean ridges, and are considered to be engybenthic, as they inhabit a layer of water that extends from just above the bottom to several feet above it. Although most of the species of the families Alepocephalidae and Platytroctidae are known from depths of 2,625–8,200 ft (800–2,500 m), a few species of the former are inhabitants of the abyssal depths, having been caught from more than 16,400 ft (5,000 m).

Not only are the osmeriforms found in a diverse array of habitats, they also live in some of the most inhospitable environments in which fishes are found. For example, fishes that live in the deep oceans, such as members of the suborder Argentinoidei, live in one of the most hostile environments on Earth, where little, if any, light visible to the human eye penetrates below 656–2,625 ft (200–800 m). Thus, deepsea fishes, depending on the amount of light entering their domain, must either have eyes that maximize light collection or rely on other senses in such a dark environment. Furthermore, such a lack of light in the ocean depths has two major effects; first, due to the lack of the warming light, temperatures in the bathypelagic zone are 35.6–41°F (2–5°C); second, as no light enters this deep zone, photosynthesis cannot occur and phytoplankton cannot survive, thus productivity is dependent on the "rain" of dead organisms and feces from the euphotic zone (the zone of light penetration) and food is consequently scarce. Third, low productivity is one thing, but the massive volume of the ocean deep means that the little food available is spread very thinly. If these factors were not enough to create a harsh environment, the added difficulty of living in deep water, where pressure increases by one atmosphere for every increase in depth of 33 ft (10 m), cannot be underestimated. Not only are chemical reactions affected by increases in pressure, but the gas solubility in the blood and tissues and the difficulty of secreting gas into the swim bladder are also increased.

In addition to the severe environmental conditions of deepsea environments, other osmeriforms, such as salamanderfish and black-stripe minnow, live in small, tannin-stained and acidic pools that often become completely dry in summer, habitats which are equally extreme.

Behavior

Published works describing the behavior of osmeriform species are scarce. The few that do exist generally describe the spawning migrations of the freshwater, anadromous, and coastal forms, or the migrations of juveniles of the amphidromous forms back into the rivers. For example, with the onset of winter rains, many galaxiids move upstream into tributaries and feeder streams where they spawn amongst flooded vegetation (western minnow), or on rocks (marbled galaxias, Galaxias olidus). During these upstream migrations, some species, such as climbing galaxias and western minnows, can "climb" obstacles as high as 33 ft (10 m) by jumping and wriggling in an eel-like fashion, using their pelvic and pectoral fins to lever themselves forward and upward. This is quite a feat, considering that individuals of these species are rarely larger than 6 in (15 cm). Species that have amphidromous populations, such as the common jollytail, undertake migrations. The adults move downstream to spawn in estuaries, the larvae that result then move out to sea before returning to the rivers in large schools of so-called whitebait. The spawning migrations of the amphidromous, anadromous, and coastal forms are described in the species descriptions of the ayu, eulachon, and the capelin, respectively.

Virtually nothing is known about the behavior of the deepsea osmeriforms. However, two behavior patterns are likely in at least some species. First, most mesopelagic fishes undergo vertical feeding migrations, in which they move to the epipelagic zone at night to feed on the abundant zooplankton found in this region. Such migrations have been recorded for at least one species within the Argentinoidea, the long-snout blacksmelt (Dolicholagus longirostris), so it is likely that other species also undertake such daily migrations. Second, many species of deepsea fishes have bioluminescent light-emitting organs called photophores, which are thought to be used for attracting mates (by flashing in particular pulse patterns), for attracting prey items, and for "hiding" the fishes from predators. The latter mechanism is thought to work in those species that live in regions into which some light just penetrates, whereby rows of photophores along the ventral surface reduce the chance that the fish is silhouetted when viewed from below.

Feeding ecology and diet

Although some representatives from most groups, including the capelin and the slender argentine (Microstoma microstoma), prey predominantly on small benthic and pelagic arthropods, others, such as the surf smelt (Hypomesus pretiosus) and European smelt (Osmerus eperlanus), have much wider diets, ingesting arthropods, fishes, mollusks, and worms. The Agassiz's slickhead (Alepocephalus agassizii) feeds on crustaceans, worms, echinoderms, and comb jellies. Other species of osmeriforms are, or become, specialist feeders. The mirrorbelly (Opisthoproctus grimaldii) is reported to feed on the stinging cells and tentacles of jellyfishes, and others, such as the ayu and black-stripe minnow, both exhibit marked shifts in diet at the end of their larval/juvenile stages.

Osmeriforms are preyed on by a wide variety of predators. For example, sharks, as well as a variety of bony fishes, seals, birds, and dolphins, have been reported to prey on the eulachon (Thaleichthys pacificus); bony fishes and squids prey on the argentines.

Reproductive biology

Fishes in the suborder Osmeroidei, such as the surf smelt and capelin, show a diverse array of breeding strategies, undergoing extensive migrations from coastal seas to surf beaches and estuaries, where they often form massive spawning aggregations, males pressing against females until they release their eggs, the males then releasing their sperm. The eggs are then fertilized and wave action buries them below the sand. Other members of the Osmeroidei, such as the eulachon and ayu, move up into rivers to spawn. Freshwater populations of Northern Hemisphere osmeroids tend to undergo similar spawning migrations, and may spawn in habitats similar to those of the migratory forms, such as the ayu. They may also spawn in different habitats. The freshwater forms of the European smelt tend to spawn in lakes, the anadromous forms spawn in rivers.

Within the Southern Hemisphere osmeroids, the Tasmanian smelt is anadromous, spending most of its life in the sea before returning to estuaries and rivers to spawn. In other species, such as the common jollytail, most populations are amphidromous. The adults of this species live in fresh water, but during autumn move downstream to spawn in estuaries. Spawning takes place on spring tides amid inundated vegetation, the eggs developing out of water and hatching two weeks later on the next spring tide. The larvae are then washed out to sea, where they feed and develop into juveniles before returning to the rivers to complete their life cycle. In purely freshwater forms such as the western minnow, migrations into tributaries or into the shallows of lakes are usual.

Within the Argentinoidei, stout blacksmelt (Pseudobathylagus milleri), and the longsnout blacksmelt produce planktonic eggs and larvae, and it is likely that other members of this suborder do likewise. Little other data are available on the reproductive behavior in the deepsea osmeriforms.

The age at first maturity, whether the adults survive to spawn in more than one year, and the spawning pattern, spawning period, and number and size of eggs vary greatly within the order. For example, anadromous forms of the European smelt do not spawn until their third or fourth year, when during a short breeding season of one to three months they produce 8,000 to 50,000 small (0.02–0.03 in/0.06–0.09 cm) demersal eggs. Adults usually die after spawning. Other species, such as the mudminnow (Galaxiella munda), which becomes mature at the end of its first year of life, has a spawning period that extends for three to four months, during which they produce several small batches (37–92) of smallish (0.06–0.05 in/0.09–0.14 cm) demersal eggs. Most mudminnow die within one or two months of spawning. Unlike the above two species, the western minnow spawns at the end of its first year and can live to spawn a further four times.

The salamanderfish is unique in the Osmeriformes in that, rather than broadcasting its eggs and sperm, it undergoes internal fertilization.

There are no reports of parental care in the Osmeriformes.

Conservation status

Eight species of Osmeriformes are listed by the IUCN. One species is classified as Extinct, one species as Endangered, one species as Critically Endangered, three species as Vulnerable, and two species as Data deficient. In addition, many Australian forms are considered by the Australian Society for Fish Biology to be data deficient to endangered, largely because of land clearing and the subsequent degradation of freshwater habitats. Many deepsea forms are small and rare, and thus are likely to be overlooked by conservationists.

Significance to humans

Due to their generally small size and/or inaccessibility (in deepsea forms), most Osmeriformes are of little importance to humans, either commercially or recreationally. However, in the Northern Hemisphere, eulachon, capelin, European smelt, and ayu form the basis of important local commercial and recreational fisheries during their spawning migrations, and in the Southern Hemisphere, the juveniles of the anadromous species, such as the Tasmanian whitebait and common jollytail, form the basis of important commercial whitebait fisheries in New Zealand and Chile. In Australia, massive falls in whitebait capture during the 1970s led to the closure of the fishery. However, it has since been reopened as a tightly regulated recreational fishery.

Species accounts

List of Species

California slickhead

Alepocephalus tenebrosus

family

Alepocephalidae

taxonomy

Alepocephalus tenebrosus Gilbert, 1892, Santa Barbara Channel, California, United States, 359–822 fathoms (2,154–4,932 ft/655–1,500 m).

other common names

None known.

physical characteristics

Total length about 23.6 in (60 cm), moderately sized, fusiform, laterally compressed; dorsal fin posteriorly placed; adipose fin absent. Skull translucent, body brown to black. Swim bladder absent.

distribution

North Pacific from Bering Sea to California; southeastern Pacific, Chile.

habitat

Marine. Deep waters, oceanic at depths 150–18,045 ft (46–5,500 m).

behavior

Little is known about the biology and behavior. However, other slickheads are gregarious, forming large schools close to the bottom.

feeding ecology and diet

Larvae and juveniles ingest benthic and planktonic crustaceans. Others feed on squids, arrow worms, comb jellies, and other deep-sea fishes such as anglerfishes.

reproductive biology

Eggs and larvae are pelagic.

conservation status

Not listed by the IUCN.

significance to humans

Not commercially sought after due to soft texture.

Greater argentine

Argentina silus

family

Argentinidae

taxonomy

Salmo silus Ascanius, 1775, Bergen, Norway.

other common names

English: Atlantic argentine; French: Grande argentine, saumon doré; German: Goldlachs; Spanish: Pez plata, sula.

physical characteristics

Standard length about 27.5 in (70 cm), moderately sized, elongate; dorsal fin medially to anteriorly placed, anterior to origin of pelvic fins. Adipose fin present. Brown to olive dorsally, silver laterally and ventrally. Mouth small, and lacks teeth on jaws.

distribution

Western Atlantic, from Davis Strait in the north, to Georges Bank in the south. Eastern Atlantic from Denmark Strait to west coast of Scotland and deeper parts of the North Sea.

habitat

Marine. Deep waters, oceanic at depths of 460–4,725 ft (140–1,440 m).

behavior

Gregarious, forms large schools close to the bottom.

feeding ecology and diet

Feeds on benthic and planktonic crustaceans, squids, arrow worms, and comb jellies. Preyed upon by bony fishes, such as swordfishes and hakes, and seals.

reproductive biology

Attains sexual maturity at the end of the fourth year. Spawns in late winter off Canada, and in April and May in the North Sea. Eggs and larvae are pelagic. Juveniles settle on the bottom of waters up to about 410 ft (125 m) deep before moving out into deeper water.

conservation status

Not listed by the IUCN. May be particularly susceptible to overfishing because they have a fairly long population doubling time of between 4.5 and 14 years.

significance to humans

A commercial fishery was started by Russia in 1963, joined by Japan in 1968. Estimated sustainable yield is 5,500–24,250 tons (5,000 to 20,000 metric tons).

Western minnow

Galaxias occidentalis

family

Galaxiidae

taxonomy

Galaxias occidentalis Ogilby, 1900, streams south of Perth, Western Australia.

other common names

English: Western galaxias.

physical characteristics

Length about 7.9 in (20 cm), small, elongate, scaleless; dorsal fin posteriorly placed. Olive green dorsally, fading to cream/white ventrally. Dark lateral bars often present.

distribution

Restricted to the southern corner of Western Australia, from approximately 155 mi (250 km) north of Perth to 50 mi (80 km) east of Albany.

habitat

Fresh waters in streams, rivers, lakes, and ponds/pools; also in brackish habitats. Schools amid riparian vegetation and open waters at all depths.

behavior

Little is known.

feeding ecology and diet

During the day most food eaten is from the water surface (e.g., flying insects and spiders), although insect larvae and small crustaceans from the substrate and within the water column are also taken. At night switches diet to freshwater shrimps.

reproductive biology

Attains sexual maturity at the end of the first year at about 2.9 in (7.5 cm). Breeding occurs during wet winter months between June and September, peaks in August (winter). Migrates into creeks or the inundated shores of lakes to spawn. Mean number of mature eggs is 905; diameter of mature eggs is 0.05 in (0.13 cm). Can live up to five years and will spawn at the end of each of these years.

conservation status

Not listed by the IUCN.

significance to humans

Fishers use them as bait for introduced trouts and European perches.

Black-stripe minnow

Galaxiella nigrostriata

family

Galaxiidae

taxonomy

Galaxias pusillus nigrostriatus Shipway, 1953, a small drain running into Marbellup Creek on a property owned by Mr. Byland, Elleker, near Albany, Western Australia.

other common names

German: Schwartzstreifen-Zwerggalaxie.

physical characteristics

Total length about 2 in (5 cm), tiny, elongate, scaleless; dorsal fin posteriorly placed. Between June and September, adults develop nuptial coloration of two longitudinal black stripes separated by a brilliant yellow (in light-colored waters) to red stripe (in dark-colored waters). In dark-colored waters, the dorsal-most black stripes extend upward and meet. Larvae show the same nuptial coloration. Outside breeding season, color is uniform brown to black, with a faint dull-yellow to red lateral stripe.

distribution

Restricted to a small area of peat flats on the southern coast of Western Australia, from Augusta in the west (about 220 mi/350 km south of Perth) to Albany in the east. Two disjunct populations about 125 mi and 250 mi (200 and 400 km) to the north were found in the 1990s, suggesting that the loss of habitat caused by massive urban and rural development during the previous hundred years had a significant impact.

habitat

Fresh waters in streams, ponds, and shallow pools. Most commonly found in highly tannin-stained and acidic ephemeral pools, in which salamanderfish also occur. Small schools found amid riparian vegetation and open waters and at all depths.

behavior

Estivates when pools become dry in summer. Large numbers are found in even the smallest pools (11.8 in/30 cm diameter) before they completely dry up. When pools were filled artificially, black-stripe minnow and salamanderfish emerged from the substrate within two hours. Unlike salamanderfish, does not apparently have any specific anatomical, physiological, or behavioral adaptations to aid estivation, and must presumably survive in crustacean burrows (and similar) that contain water through the dry season.

feeding ecology and diet

Active carnivores at all stages. The smallest larvae, 0.19–0.43 in (0.5–1.1 cm), feed predominantly on rotifers; larger larvae, 0.5–0.9 in (1.2–2.3 cm) consume fewer rotifers, but far more small crustaceans and insect larvae. Juveniles and adults continue to take crustaceans and insect larvae, but a large part of their diet consists of terrestrial insects and spiders taken from the surface. Larvae and small juveniles assume a head-down, tail-up stance (between 30 and 45°), forming their body into an "S" shape as prey approaches, striking at high speed when the prey is within about half a body length.

reproductive biology

Sexually mature at the end of the first year, when males are about 1.3 in (3.3 cm) and females 1.4 in (3.7 cm). Individuals spawn several times between June and September, peak activity in late June/early July. Mean number of mature eggs is 62; diameter is 0.03 in (0.07 cm). Most adults die within two months of spawning.

conservation status

Not listed by the IUCN. Regarded as vulnerable by the Australian Society for Fish Biology.

significance to humans

The Western Australian Department of Fisheries and commercial breeders of ornamental fishes are considering its suitability as an aquarium fish.

Salamanderfish

Lepidogalaxias salamandroides

family

Lepidogalaxiidae

taxonomy

Lepidogalaxias salamandroides Mees, 1961. Tiny creek about 6 mi (9.6 km) east-northeast of Shannon River, Western Australia.

other common names

English: Shannon mudminnow; German: Salamanderfisch.

physical characteristics

Length about 2.9 in (7.5 cm), small, elongate; dorsal fin posteriorly placed. Scales absent on head, back, and belly. Pelvic fins well developed, even at hatching. Males have enlarged anal fin sheathed with scales. Brown to gray overall, dark saddlelike markings dorsally, and blotches laterally, the latter forming a pair of stripes during breeding.

distribution

Restricted to a small area of peat flats on the southern coast of Western Australia. Used to extend from Margaret River in the west (about 186 mi/300 km) south of Perth) to Albany in the east; in 2003 its range had contracted to central 93–125 mi/150–200 km) of this area.

habitat

Fresh waters in streams, ponds, and shallow pools. Most common in ephemeral, tannin-stained, highly acidic (pH 3.0) pools that can exceed 95°F (35°C) in summer. Solitary and benthic, rests on pelvic fins amid riparian vegetation and in open waters. Larvae and juveniles most common in very shallow water (less than 3.9 in/10 cm), tend to move into deeper waters (usually less than 39.4 in/1 m) as they grow.

behavior

Exhibits several behaviors rare among fishes. Like lungfishes, estivates when pools in which they live become dry, burrowing into the substrate, forming an "S" shape, and producing a mucous cocoon, emerging when pools refill with winter rain. Unlike black-striped minnow, buries itself before the pool becomes almost dry.

feeding ecology and diet

Active carnivore at all stages, feeds on small crustaceans and insect larvae. Individuals rest on the substrate with their head and body raised up, supported by the large pelvic fins present at hatching. Unlike any other species of fishes, salamanderfish have very large gaps between the vertebrae immediately behind the head. These gaps allow them to move their head from side to side when scanning for prey, which is crucial, as muscles that allow movement of the eyes are absent or greatly reduced. When prey are within about half a body length, darts forward, engulfing and swallowing prey whole.

reproductive biology

About 27% attain sexual maturity and spawn at the end of the first year, when males are 1.5 in (3.9 cm) and females are about 1.7 in (4.3 cm). All two-year-old fishes mature and spawn. Each individual spawns several times between late May and late August, peak activity in late July/early August. Mean number of mature eggs is approximately 82; diameter is 0.07 in (0.18 cm). Many fish survive to spawn in two seasons, but only a few survive to spawn at the end of the third and fourth years. Spawning behavior is unique. Males develop an enlarged anal fin surrounded by a sheath of scales. On finding a receptive female, a male will approach and nudge her sides, if she does not swim away or react aggressively, he will approach from the side, and using his scale sheath grasp the female around her anal fin and cloaca. Sperm is introduced into the female via his enlarged anal fin. In the laboratory, males may remain attached to a female for several hours. When physically removed, a male always reattaches from the same side; apparently, just like humans, salamanderfish are either right or left "handed."

conservation status

Not listed by the IUCN. Regarded as vulnerable by the Australian Society for Fish Biology.

significance to humans

None, although the Western Australian Department of Fisheries and commercial breeders of ornamental fishes are considering its suitability as an aquarium fish.

California smoothtongue

Leuroglossus stilbius

family

Microstomatidae

taxonomy

Leuroglossus stilbius Gilbert, 1890, Pacific off northwestern Mexico, Albatross sta. 2997, 221 fathoms (1,326 ft/400 m).

other common names

English: Esperlan, smoothtongue, southern smoothtongue; Spanish: Esperlan, esperlan de lengua suave.

physical characteristics

Length about 7.9 in (20 cm), small to moderately sized, elongate; dorsal fin medially placed; adipose fin present; eyes large. Body light to dark, may be silvery.

distribution

Eastern Pacific from Oregon, United States, in the north, to Gulf of California, Mexico, in the south.

habitat

Marine. Deep waters, oceanic at depths between surface and 2,265 ft (690 m).

behavior

Gregarious, forms large schools.

feeding ecology and diet

Benthic and planktonic crustaceans, worms, and tunicates have been recorded in the guts of juveniles. Reported to be preyed upon by tunas off the coast of the United States. Likely to have specialized eyes as those of some close relatives. Eyes are positioned on the top of the head to increase binocular vision, and in each eye a gap in front of the lens increases illumination of the retina, which itself has specialized photoreceptors. These specializations ensure great visual sensitivity in the forward plane and spatial perception, attributes particularly relevant when searching for prey in dim environments.

reproductive biology

Spawning occurs in the California Current between December and May. Eggs and larvae are pelagic.

conservation status

Not listed by the IUCN.

significance to humans

None known.

Barreleye

Macropinna microstoma

family

Opisthoproctidae

taxonomy

Macropinna microstoma Chapman, 1939, northeastern Pacific, 53°50"00"N, 134°20"00", 2,950–2,300 ft (900–700 m) wire out.

other common names

English: Pacific barreleye; Japanese: Demenigisu.

physical characteristics

Length about 1.8 in (4.5 cm). Small, deep-bodied, laterally compressed; dorsal fin posteriorly placed; adipose fin present. Eyes telescopic and large. Head clear, body black dorsally and ventrally, may be silver laterally.

distribution

North Pacific from Bering Sea in the north to Japan and Mexico in the south.

habitat

Marine. Deep waters, oceanic at depths about 330–2,950 ft (100–900 m).

behavior

Nothing known.

feeding ecology and diet

Not much is known. Other barreleye feed on stinging cells of jellyfishes. Each stalked eye in the closely related brownsnout spookfish (Dolichopteryx longipes) has two retinas, one directly below the lens, the other to the side of the lens. The first retina contains a golden to silvery pigment that ensures any light is reflected backward and forward, passing through photoreceptors several times before its energy is expended, and thus maximizing the efficiency of the eye. The second retina, although not as efficient, permits the barreleye to distinguish the movement of brightly lit objects, and thus see prey from below. Due to the excellent binocular vision provided by these tubular eyes, the barreleye can determine position precisely, and can also see predators that may be approaching from its side. Such optic specializations thus aid in both feeding and predator avoidance.

reproductive biology

Larvae, and probably eggs, are pelagic.

conservation status

Not listed by the IUCN.

significance to humans

None known.

Capelin

Mallotus villosus

family

Osmeridae

taxonomy

Mallotus villosus Muller, 1776, Iceland.

other common names

English: Whitefish, lodde; French: Capelan atlantique; German: Lodde; Spanish: Capelan.

physical characteristics

Total length about 9.8 in (25 cm). Small, moderately deep bodied; dorsal fin medially placed; adipose fin with long base. Body covered in small scales. Olive dorsally, silver laterally and ventrally. Enlarged pectoral and anal fins; two ridges of enlarged scales along each side of body in breeding males.

distribution

Circumpolar in the Arctic, North Atlantic, and North Pacific Oceans.

habitat

Marine. Oceanic moving into coastal seas to spawn. Found down to about 985 ft (300 m).

behavior

Little is known.

feeding ecology and diet

All stages feed on zooplankton and small benthic organisms such as euphausiid shrimps, copepods, amphipods, and worms. Predators such as rays, a range of bony fishes, seabirds, seals, whales, and dolphins take an estimated 3.3 million tons (3 million metric tons) in the northwest Atlantic.

reproductive biology

Forms massive spawning aggregations over shallow banks. Spawns over a two to three month period between March and October, depending on location. Two males flank and hold a female with enlarged fins and scale ridges until she releases her eggs, they then release the sperm. Females release up to 12,000 adhesive eggs. Many individuals survive to spawn in more than one year, although most spawning animals are in year three or four. Many fish spawning along shorelines, particularly males, become stranded on beaches and die.

conservation status

Not listed by the IUCN.

significance to humans

Very important in commercial, recreational, and traditional fisheries throughout the range. In 1998 the commercial fishery in the northwest Atlantic was estimated at 121,000 tons (110,000 metric tons). Marketed fresh, frozen, salted, dried, smoked, as fish meal (males), and roe (females).

Ayu

Plecoglossus altivelis

family

Osmeridae

taxonomy

Salmo (Plecoglossus) altivelis Temminck and Schlegel, 1846, Japan.

other common names

English: Ko-ayu, sweetfish; French: Ayu; Japanese: Koayu.

physical characteristics

Length about 11.8 in (30 cm). Small, moderately deep bodied; dorsal fin medially placed; adipose fin present. Body covered in small scales. Olive dorsolaterally, white ventrally.

distribution

Coastal seas and rivers in Japan, China, Korea, and Taiwan.

habitat

Marine, brackish, and fresh waters. Amphidromous, demersal in coastal seas, estuaries, rivers, streams, and lakes to a depth of about 33 ft (10 m). Landlocked forms also exist. In rivers and lakes appears to prefer clear waters.

behavior

Except for feeding and reproduction little is known regarding specific behavior patterns. In rivers, form territories, which they guard by attacking and nipping other ayu.

feeding ecology and diet

Larvae and juveniles feed primarily on small benthic crustaceans such as copepods and amphipods. Juveniles of the amphidromous form move into fresh waters in winter and spring, moving up into the higher reaches of rivers and streams. Adults use specially modified jaws and teeth to scrape algae from rocks. Adults have also been reported to eat small pebbles, although it seems likely that these were inadvertently ingested while grazing on algae. The few adults that survive spawning and return to the sea have been reported to feed on zoobenthos.

reproductive biology

Sexual maturity usually attained at end of first year at about 7.9–11.8 in (20–30 cm). Spawns in freshwater during autumn, when adults move downstream to the spawning grounds. At night, excavates small pits in sand or gravel banks into which about 10,000 adhesive eggs (0.04 in/0.1 cm) are released. Eggs hatch 14–20 days later. Larger individuals spawn once, after which most die; smaller individuals have about a 50% chance of surviving to spawn again two weeks later.

conservation status

Not listed by the IUCN.

significance to humans

Ayu form important commercial, aquaculture, recreational, and traditional fisheries. In Japan the commercial fishery and aquaculture accounted for 16,500 tons (15,000 metric tons) and 8,820 tons (8,000 metric tons), respectively, in 1979. Sport fishing in Japan involves baited hooks, flies, as well as a traditional method. In the traditional method, an ayu that has a small free-swinging treble hook fastened to it is attached to the line. Anglers swing the attached fish to ayu guarding territory, and when the resident fish nips the back of the "invader" it is caught on the free-swinging hook. In Japan the ayu forms the basis of the cormorant fishery, whereby cormorants are trained to dive for fish. This fishery is believed to date back at least 2,500 years, but is now for tourists.

Eulachon

Thaleichthys pacificus

family

Osmeridae

taxonomy

Salmo (Mallotus?) pacificus Richardson, 1836, Columbia River, no higher than Katpootl, northwestern United States.

other common names

English: Candlefish, oilfish, fathom fish, hooligan; French: Eulachon.

physical characteristics

Total length 11.8 in (30 cm), small, slender bodied; dorsal fin medially placed; adipose fin present. Body covered in small scales. Brown to blue dorsally, silver laterally, white ventrally. Raised ridge along middle of body; large tubercles on fins of breeding males are absent or small in females.

distribution

Northwest Pacific between 61° and 36°N. From west of Saint Matthew Island and Kuskokwim (Bering Sea) in the north to Monterey Bay in northern California in the south.

habitat

Marine, brackish, and fresh waters. Anadromous, found in coastal seas, estuaries, rivers, and streams to a depth of 2,050 ft (625 m). Landlocked forms exist.

behavior

Little is known.

feeding ecology and diet

All stages feed on zooplankton and small benthic crustaceans such as mysid and euphausiid shrimps, as well as copepods and amphipods. Adults do not feed in freshwater. Reported to be preyed upon by dogfishes, salmonids, cods, flatfishes, sturgeons, seagulls, seals, and porpoises.

reproductive biology

Sexual maturity is attained at end of third year. Spawning migrations from the sea to rivers occur when river temperatures rise above 40°F (4.4°C), spawns in spring after the ice melt. Sticky eggs with a short stalk are broadcast over sand or gravel. Larvae hatch after about 30 days and are swept downstream and out to sea. Most adults die following spawning, a few survive for five years. Adults may return to natal streams to spawn.

conservation status

Not listed by the IUCN.

significance to humans

Traditionally an important fishery for Native Americans for food and oil. Fish are so oily they were dried and used as candles. Used as food for minks and other animals farmed for fur.

Australian smelt

Retropinna semoni

family

Retropinnidae

taxonomy

Prototroctes semoni Weber, 1895, Burnett River, Queensland, Australia.

other common names

German: Australischer Stint; Polish: Rakietniczka semona.

physical characteristics

Total length 3.9 in (10 cm), small, elongate; dorsal fin posteriorly placed; adipose fin present. Scales absent on head. Olive green dorsally, golden to orange or purple laterally, silvery ventrally. Fins enlarged in breeding males. Has only a left gonad. Often smells of cucumber when fresh.

distribution

Widespread in coastal drainages of southeastern Australia, from the Fitzroy River in southern Queensland to eastern South Australia; also in the Cooper Creek drainage of Lake Eyre.

habitat

Slow-flowing streams and rivers, lakes, and ponds/pools; also in brackish habitats. Schools among riparian vegetation and open waters at all depths.

behavior

Gregarious, forms large schools from midwater to the surface in large open waters.

feeding ecology and diet

Feeds on insects, microcrustaceans, and algae. An important component of the diets of other fishes.

reproductive biology

Sexual maturity usually attained at end of first year at about 2–3.9 in (5–10 cm). Some fish from inland and northern drainages may reach maturity in 9–11 months and at less than 1.6 in (4 cm). Spawns in fresh waters during spring. Spawning individuals develop nuptial tubercles on scales and fin rays. Releases 100–1,000 adhesive eggs (0.03 in/0.08 cm) over the streambed and/or aquatic vegetation. Larvae of about 0.18 in (0.45 cm) hatch after 10 days. Coastal populations may be amphidromous.

conservation status

Not listed by the IUCN.

significance to humans

Introduced to Tasmania as forage for introduced trouts.

Resources

Books

Allen, G. R. Freshwater Fishes of Australia. Neptune City, NJ: T. F. H. Publications, 1989.

Allen, G. R., S. H. Midgley, and M. Allen. Guide to the Freshwater Fishes of Australia. Perth: Western Australian Museum, 2002.

Berra, T. M. An Atlas of Distribution of the Freshwater Fish Families of the World. Lincoln: University of Nebraska Press, 1981.

Coad, B. W. Guide to the Marine Sport Fishes of Atlantic Canada and New England. Toronto: University of Toronto Press, 1992.

Eschmeyer, W. N. Catalog of the Genera of Recent Fishes. San Francisco: California Academy of Sciences, 1990.

Fink, W. L. "Basal Euteleosts: Relationships." In Ontogeny and Systematics of Fishes, edited by H. G. Moser, W. J. Richards, D. M. Cohen, M. P. Fahay, A. W. Kendall, Jr., and S. L. Richardson, Special Publication Number 1. Lawrence, KS: American Society of Ichthyologists and Herpetologists, Allen Press, 1984.

Glover, J. C. M. "Argentinidae, Bathylagidae, Opisthoproctidae, Alepocephalidae, and Platytroctidae." In The Fishes of Australia's South Coast, edited by M. F. Gomon, J. C. M. Glover, and R. H. Kuiter. Adelaide, Australia: State Print, 1994.

Helfman, G. S., B. B. Collette, and D. E. Facey. The Diversity of Fishes. Malden, MA: Blackwell Science, 1997.

Johnson, G. D., and C. Patterson. "Relationships of Lower Euteleostean Fishes." In Interrelationships of Fishes, edited by M. L. J. Stiassny, L. R. Parenti, and G. D. Johnson. San Diego: Academic Press, 1996.

Koehn, J. D., and W. G. O'Connor. Biological Information for Management of Native Freshwater Fish in Victoria. Melbourne: Victorian Government Printing Office, 1990.

Marshall, N. B. Developments in Deep-Sea Biology. Poole, Australia: Blandford Press, 1979.

McDowall, R. M. Diadromy in Fishes: Migrations Between Freshwater and Marine Environments. London: Croom Helm, 1988.

——. Freshwater Fishes of South-Eastern Australia. Sydney: Reed Books, 1996.

Morgan, D. L., H. S. Gill, and I. C. Potter. Distribution, Identification and Biology of Freshwater Fishes in South-Western Australia. Perth, Australia: Western Australian Museum, 1998.

Nelson, J. S. Fishes of the World, 3rd edition. New York: John Wiley & Sons, 1994.

Paxton, J. R., and D. M. Cohen. "Argentinidae." In Living Marine Resources of the Western Central Pacific. Vol. 3, Batoid Fishes, Chimaeras and Bony Fishes, Part 1 (Elopidae to Linophrynidae), edited by K. E. Carpenter and V. H. Niem. Rome: FAO, 1999.

——. "Alepocephalidae." In Living Marine Resources of the Western Central Pacific. Vol. 3, Batoid Fishes, Chimaeras and Bony Fishes, Part 1 (Elopidae to Linophrynidae), edited by K.E. Carpenter and V. H. Niem. Rome: FAO, 1999.

——. "Bathylagidae" In Living Marine Resources of the Western Central Pacific. Vol. 3, Batoid Fishes, Chimaeras and Bony Fishes, Part 1 (Elopidae to Linophrynidae), edited by K.E. Carpenter and V. H. Niem. Rome: FAO, 1999.

——. "Opisthoproctidae." In Living Marine Resources of the Western Central Pacific. Vol. 3, Batoid Fishes, Chimaeras and Bony Fishes, Part 1 (Elopidae to Linophrynidae), edited by K.E. Carpenter and V. H. Niem. Rome: FAO, 1999.

Sazonov, Y. I. "Platytroctidae." In Living Marine Resources of the Western Central Pacific. Vol. 3, Batoid Fishes, Chimaeras and Bony Fishes, Part 1 (Elopidae to Linophrynidae), edited by K.E. Carpenter and V. H. Niem. Rome: FAO, 1999.

Sazonov, Y. I., and D. F. Markle. "Alepocephalidae." In Living Marine Resources of the Western Central Pacific. Vol. 3, Batoid Fishes, Chimaeras and Bony Fishes, Part 1 (Elopidae to Linophrynidae), edited by K. E. Carpenter and V. H. Niem. Rome: FAO, 1999.

Wheeler, A. The World Encyclopedia of Fishes. London: Macdonald, 1985.

Periodicals

Allen, G. R., and T. M. Berra. "Life History Aspects of the West Australian Salamanderfish, Lepidogalaxias salamandroides Mees." Records of the Western Australian Museum 14 (1989): 253–267.

Begle, D. P. "Monophyly and Relationships of Argentinoid Fishes." Copeia (1992): 350–366.

——. "Relationships of the Osmeroid Fishes and the Use of Reductive Characters in Phylogenetic Analysis." Systematic Zoology 40 (1991): 33–53.

Berra, T. M., and G. R. Allen. "Burrowing, Emergence, Behaviour, and Functional Morphology of the Australian Salamanderfish, Lepidogalaxias salamandroides." Fisheries 14 (1989): 2–10.

——. "Population Structure and Development of Lepidogalaxias salamandroides (Pisces: Salmoniformes) from Western Australia." Copeia (1991): 845–850.

——. "Inability of Salamanderfish, Lepidogalaxias salamandroides, to Tolerate Hypoxic Water." Records of the Western Australian Museum 17 (1995): 117.

Gill, H. S., and D. L. Morgan. "Larval Development in the Salamanderfish, Lepidogalaxias salamandroides." Copeia (1999): 219–224.

——. "Ontogenetic Changes in the Diet of Galaxiella nigrostriata (Shipway, 1953) (Galaxiidae) and Lepidogalaxias salamandroides Mees, 1961 (Lepidogalaxias)." Ecology of Freshwater Fish (in press).

Gill, H. S., and F. J. Neira. "Larval Descriptions of Three Galaxiid Fishes Endemic to South-Western Australia: Galaxias occidentalis, Galaxiella munda and Galaxiella nigrostriata (Salmoniformes: Galaxiidae)." Australian Journal of Marine and Freshwater Research 45 (1994): 1,307–1,317.

Iguchi, K., and Y. Tsukamoto. "Semelparous or Iteroparous: Resource Allocation Tactics in the Ayu, an Osmeroid Fish." Journal of Fish Biology 58 (2001): 520–528.

McDowall, R. M., and R. S. Frankenberg. "The Galaxiid Fishes of Australia (Pisces: Galaxiidae)." Records of the Australian Museum 33 (1981): 443–605.

McDowall, R. M., and B. J. Pusey. "Lepidogalaxias salamandroides Mees: A Redescription, with Natural History Notes." Records of the Western Australian Museum 11 (1983): 11–23.

Morgan, D. L., and H. S. Gill. "Fish Associations Within the Different Inland Habitats of Lower South-Western Australia." Records of the Western Australian Museum 20 (2000): 31–37.

Morgan, D. L., H. S. Gill, and I. C. Potter. "Age Composition, Growth and Reproductive Biology of the Salamanderfish Lepidogalaxias salamandroides: A Re-examination." Environmental Biology of Fishes 57 (2000): 191–204.

Morgan, D. L., D. C. Thorburn, and H. S. Gill. "Salinization of South-western Western Australian Rivers and the Implications for the Inland Fish Fauna: The Blackwood River, a Case Study." Pacific Conservation Biology (in press).

Pen, L. J. and I. C. Potter. "Biology of the Western Minnow, Galaxias occidentalis Ogilby (Teleostei: Galaxiidae), in a South-Western Australian River. 1. Reproductive Biology." Hydrobiologia 211 (1991): 77–88.

——. "Biology of the Western Minnow, Galaxias occidentalis Ogilby (Teleostei: Galaxiidae), in a South-Western Australian River. 2. Size and Age Composition, Growth and Diet." Hydrobiologia 211 (1991): 89–100.

Pen, L. J., H. S. Gill, I. C. Potter, and P. Humphries. "Growth, Age Composition, Reproductive Biology and Diet of the Black-Stripe Minnow Galaxiella nigrostriata (Shipway), Including Comparisons with the Other Two Galaxiella Species." Journal of Fish Biology 43 (1993): 847–863.

Pen, L. J., I. C. Potter, and R. W. Hilliard. "Biology of Galaxiella munda McDowall (Teleostei: Galaxiidae), Including a Comparison of the Reproductive Strategies of This and Three Other Local Species." Journal of Fish Biology 39 (1991): 717–731.

Pusey, B. J. "The Shannon Mud Minnow." Fishes of Sahul: Journal of Australia and New Guinea Fishes Association 1 (1983): 9–11.

——. "Aestivation in the Teleost Fish Lepidogalaxias salamandroides Mees." Comparative Biochemistry and Physiology 92A (1989): 137–138.

——. "Seasonality, Aestivation and the Life History of the Salamanderfish Lepidogalaxias salamandroides (Pisces: Lepidogalaxiidae)." Environmental Biology of Fishes 29 (1990): 15–26.

Rosen, D. E. "Phylogeny and Zoogeography of Salmoniform Fishes and Relationships of Lepidogalaxias salamandroides." Bulletin of the American Museum of Natural History 153 (1974): 265–326.

Waters, J. M., J. A. Lopez, and G. P. Wallis. "Molecular Phylogenetics and Biogeography of Galaxiid Fishes (Osteichthyes: Galaxiidae): Dispersal, Vicariance, and the Position of Lepidogalaxias salamandroides." Systematic Zoology 49 (2000): 777–795.

Howard Stamper Gill, PhD