This paper completes a survey of the strictly fresh-water Philippine fishes, within the limits set in the introduction to Part I. The remaining species are few; namely, dalag, climbing perch, two catfishes of general or wide distribution, and one, highly localized osphronemid. Any further discussion of the fishes found in the rivers and lakes of the Philippines, unless limited to single species or genera, would necessitate a consideration of forms dwelling largely in brackish or salt water and is therefore omitted. One order, including three families, and two families belonging to the order of catfishes, with two new genera and two new species, are here presented.
In this paper the length recorded does not include the caudal fin, except where so stated.
An assemblage of fishes, either perchlike with oblong and compressed, or elongate and more or less cylindrical body, characterized especially by the presence of a large cavity in the head above the gills. The latter is a peculiar modification of the upper elements of one of the pairs of gill-bearing arches. Instead of the branchihyals being straight and solid, as in most fishes, they are excessively developed and in all except the Ophicephalidae are provided with several thin plates or folds, erect from the surface of the bones and the roof of the skull. These by their intersection form an elaborate apparatus or labyrinth of thin plates and chambers lined with a vascular membrane well supplied with large blood vessels. Into the suprabranchial cavity atmospheric air is taken direct, the fish rising to the surface for the purpose of inhaling the air; if prevented from so doing it dies of suffocation, the gills alone apparently not being able sufficiently to oxygenate the blood. The suprabranchial chamber communicates with the branchial cavity by an opening above the two anterior gill slits, and may be separate from the pharyngeal cavity or in open communication with it, as in the Ophicephalidae. Scales large to medium in size, ctenoid or cycloid; lateral line present and continuous or interrupted, vestigial, or absent; dorsal fin single, long, origin above or before base of pectorals and longer than anal, or shorter than anal and beginning behind base of pectorals; dorsal and anal with numerous spines of variable number or spines absent; ventrals thoracic, subabdominal, of six rays, the outer spinous in Philippine species; gills four; pseudobranchiae none or rudimentary; pyloric appendages few or none; air bladder present or absent.
This order is confined to the fresh waters of the East Indies, southeastern and southern Asia, and tropical Africa. The various species have the - power of being able to live out of the water for, some, time, or to live in semifluid mud, or even to lie in a half-torpid condition in the thick mud beneath the hard-baked crust of the bottom of a pond or water hole, They are not able, however, to live in mud from which all moisture has disappeared, as popular superstition credits them to be; when their gills are entirely dry they die as do other fishes.
Elongate and more or less cylindrical fishes, the posterior portion strongly compressed laterally; head large, depressed, covered above with very large shieldlike scales, those of the rest of the body of medium size, cycloid and much striated; all the fins lack spines; dorsal and anal long, undivided, with many rays, the pectorals large and the ventrals thoracic when present; the pelvic bones attached to the symphysis of the clavicles by a ligament; mouth large, upper lip protractile, though I have never seen a living fish extend it; maxillaries outside margin of mouth, bands of small or cardiform curved teeth on intermaxillaries, vomer, palatines, and mandibles; canine teeth also always present on mandibles and sometimes on vomer and palatines; lateral line nearly always curved more or less abruptly in its anterior half or may be partially interrupted; air bladder continued into an elongation of abdominal cavity in tail; four gills; gill rakers present but no pseudobranchiae; gill membranes connected with each other but free from isthmus.
Above the gills is a large cavity, connected with the throat and serving as an accessory breathing organ. These fish go to the top and inhale air directly, the osmotic transfer of gases taking place through the mucous membrane that lines the cavity. In this way they are able to live in imperfectly oxygenated water or in mud, and to endure prolonged removal from water. Their position in the water is indicated by the bubbles which they expel at frequent intervals. So dependent are they upon the oxygen derived from directly inhaled air that they drown if kept in a vessel where they are prevented from coming to the surface of the water now and then.
This family includes two genera, and occurs from Formosa and Halmahera to Hindustan, Ceylon, and tropical Africa. But one occurs in the Philippines.
Of the four species given in the key I have found but - one in the Philippines: Ophicephalus maculatus .
|Ophicephalus melasoma BLEEKER,||Nat. Tijdschr. Ned. Indie 2 (1851) 424.|
|Ophiocephalus melanosoma GÜNTHER,||Cat. Fishes Brit. Mus. 3 (1861) 473|
|BLEEKER, Atlas Ichth. 9 (1877) pl. 399, fig. 4|
|BOULENGER, Ann. & Mag. Nat. Hist. VI 15 (1895) 186|
|WEBER and BEAUFORT, Fishes Indo-Austr. Arch. 4 (1922) 319 .|
Depth 5 to 5.8, and 5.9 to 7.2 in length with caudal; head 3.1 to 3.3, and 3.8 to 4.2 in length with caudal; eye 5.7 to 7 in head, twice or a little less in interorbital space.
Cylindrical anteriorly, compressed posteriorly; head depressed, its upper profile straight, and interorbital space flat; snout less than twice diameter of eye; maxillary reaching from hind border of eye to far beyond eye; lower jaw slightly prominent, cleft of mouth rather oblique; a rather broad villiform band of teeth in interinaxillaries, teeth near angle coarser, especially the posterior ones; a patch of moderately strong teeth on vomer and an elongate band of strong teeth on palatines, the inner row largest and caniniform; several rows of teeth near symphysis of lower Jaw, passing into a single row at sides, behind which are strong, widely spaced canines, all teeth curved backward; five or six scales in a row between eye and hind border of operculum and three to four rows on operculum; lateral line with an abrupt downward curve of three scales at fourteenth or fifteenth scale; fifteen to sixteen scales between tip of snout and origin of dorsal, which is behind base of pectorals; dorsal extends beyond tip of anal; pectorals about as long as from eye to posterior margin of head; ventrals as in O. striatus .
Color in alcohol dark greenish or bluish above, yellowish. or reddish brown below; a rather inconspicuous dark oblique spot behind corner of mouth; underparts of head sometimes with yellow spots; pectorals, dorsal, and caudal dark, ventrals of the color of the lower parts, sometimes striped posteriorly; anal light, with a subterminal dark band. Attaining a length of 285 millimeters.
This species is included on the authority of Boulenger, who determined as such three specimens collected by Everett on Balabac Island. I have seen no material, the above description being compiled from Weber and Beaufort.
As in O. striatus , young specimens have a red lateral band from snout to caudal.
Ophicephalus melasoma occurs in the East Indies on the islands of Sumatra, Banca, and Borneo, and in Tonquin and Siam on the mainland.
|Ophicephalus striatus BLOCH,||Ausländ. Fische 7 (1793) 141, pl. 359|
|CUVIER & VALENCIENNES, Hist. Nat. Poiss. 7 (1831) 313, pls. 202 and 206. 474.|
|Ophiocephalus striatus GÜNTHER,||Cat. Fishes Brit. Mus. 3 (1861)|
|BLEEKER, Atlas Ichth. 9 (1877) pl. 399, fig. 1|
|SMITH, Bull. U. S. Fish Comm. 21 (1901) 17|
|JORDAN and SEALE, Proc. U. S. Nat. Mus. 28 (1905) 782 ; Bull. U. S. Bur. Fisheries 26 (1906) 27|
|EVERMANN and SEALE, Bull. U. S. Bur. Fisheries 26 (1906) 103; Proc. U. S. Nat. Mus. 31 (1907) 507|
|WEBER and BEAUFORT, Fishes Indo-Austr. Arch. 4 (1922) 317.|
|Ophiocephalus vagus PETERS,||Monatsber. Akad. Berlin (1868) 260.|
|? Ophiocephalus melanopterus||SMITH and SEALE, Proc. Biol. Soc. Washington 19 (1906) 79.|
Dalag in Tagalog and many other Philippine dialects; aluan or haluan and aruan or haruan in Moro and Visayan; haroan , to, rabo , terebog , and talosog in Bikol; bakule and bulig are Tagalog names applied to young dalag,
Dorsal 37-43; anal 23-27; pectoral 15-17; ventral 6; lateral line 52-58; scales in transverse series 4/(8 - 10), not counting the lateral line.
Depth 5 to 6, head 3 to 3.3 in length without caudal, and 3.6 to 4 in total length; eye 4.4 to 8.5 in head, 1.6 to 2 in interorbital space, and 1.2 to 1.75 in snout.
The large broad head flat between eyes, upper profile but little convex, being more like an inclined plane; trunk hardly cylindrical but more or less flattened on sides even just behind head and strongly compressed posteriorly; eyes large, prominent, and somewhat projecting in life; the slightly oblique mouth large, the maxillary reaching well beyond eye, except in the very young (in a specimen 32 millimeters long it extends-but a little beyond pupil); snout broad, rounded, lower jaw projecting; teeth in upper jaws (intermaxillaries) very small, recurved, in broad bands, tapering posteriorly, of from five or six to eight or nine rows, those behind symphysis fewer, coarser, longer, and some of them caninelike; teeth on vomer and palatines in about three or four rows, much larger than those on interinaxillaries, recurved, palatine teeth larger than those of vomer, some of them caniniform; teeth of mandibles in a patch of from three to five rows of teeth near symphysis, posteriorly with but one row of widely spaced canines larger than any of the other teeth in either jaw; pectorals shorter than postorbital part of head; lateral, line with a downward curve, usually including three scales at sixteenth to twentieth scale.
Color of specimens in alcohol above greenish or bluish to almost black, becoming white, silvery, or brownish beneath; dark streaks and blotches both above and below, including dorsal and anal fins and forming diagonal bars running forward and meeting at right angles on sides, these obscured or obsolete in old specimens; undersurface white, with dark or. brown dots,,dashes, and irregular or curved spots; a dark stripe from angle of mouth to suboperculum, sometimes fading and disappearing; pectorals dark, like the back; ventrals pale to w whitish, spotted with dark brown or posterior half dark like the back; caudal very dark, or with crossbars of light and dark.
Color in life of a specimen raised from the egg, in my office 375 millimeters long over all, pale muddy or brownish gray above and on sides with darker mottlings on head and dark brown bands or blotches across back and passing diagonally downward and forward to middle of, side, where they may meet at right. angles more or less clearly defined similar bars from below or be continued downward stopping at the white of belly and underparts, which. are spotted with dark brown; a dark bar from corner of mouth backward and downward to opercle; dorsal fin clear to muddy, with flecks of brown; pectorals and ventrals colorless, with a few dark spots; anal and caudal very dark with a bronze greenish cast; eyes large, very prominent, with orange red iris.
Dalag is the most important fresh-water food fish in the Philippines, and occurs in lakes and lowland rivers throughout the islands from Siasi northward. While I have examined vast numbers of specimens from Jolo to Aparri, it is apparent that the original habitat of this fish did not include all the Philippine waters in which we now find it. Dalag abound in Lake Lanao but it is very evident that they have been planted there by the Moros. The Tagabilis claim to have taken them to Lake Sebu in the high mountains of southern Cotabato Province, while we know positively that they were carried by Christian Filipinos from Laguna de Bay, Luzon, to Lake Balinsasayao, the name applied to two small crater lakes at an altitude of about 1,050 meters in Oriental Negros, near Dumaguete. In like manner dalag have been distributed to lowland rivers and ponds all over the Islands, until they now occur wherever they can maintain themselves.
No systematic attempts have been made to cultivate dalag, though some of the Ifugaos stock their rice paddies with the fry and harvest them a few months later, while now and then some person attempts to grow them in a natural or artificial pond. The greatest obstacle to growing dalag commercially is their carnivorous habit and the difficulty of obtaining any cheap animal food in the Philippines. If this obstacle could be over come they could be grown easily in large numbers.
Dalag are monogamous and reproduce during every month in the year in the Philippines, while unquestionably many, if not all, breed twice a year. The eggs are laid in a nest of water plants, usually some species of alga, in the center of which they float, lying flush with the surface of the water. They are of a golden yellow color, about a millimeter in diameter, and from five hundred or so to perhaps a few thousand in number.
One or other of the parents guards the nest at all times, lying concealed beneath it. The eggs hatch in two or three days and the fry swim about in a dense mass, protected by one or both parents, a single individual hardly visible except for its golden eyes. In a short time the fry assume a characteristic orange color and are very handsome lively little fish, incessantly journeying up and down in the water and emitting bubbles of air as they come to the surface. As they grow larger their color changes and the orange remains only as a longitudinal lateral stripe. The school remains together until the fry reach a length of 50 or 60 millimeters or more, always continuing the habit of coming to the top for air and diving beneath, but no longer doing so in unison, and more and more separating from each other.
As time goes on their numbers become greatly diminished. Of the original eggs, many do not hatch owing to the attacks of water fungi; while fungi, various parasites both internal and external, insects and insect larvae, crustaceans, birds, and other fishes levy toll upon the fry. If food is scarce the adults gobble the young dalag as quickly as any other morsel.
With increased size the school scatters, each fish taking up a solitary abode, and the colors turn to brownish, with darker, diagonal, angled crossbars and a conspicuous dark ocellus at the posterior end of the dorsal; this gradually fades and the adult color and markings are assumed before the fish are a year old.
I have grown many in my office, and find that they become sexually mature in about eighteen months, when they may have a length of 250 millimeters or more. Specimens of the same age grown in ponds are much larger, however. As previously noted, one specimen raised in my office attained a length of 375 millimeters in two years and three months. Although this species is said by Weber and Beaufort to reach a length of over 900 millimeters, I have never seen any in the Philippines more than about 600 millimeters long. Such large, bulky, specimens are several years old and are rare except in places such as Lake Lanao, Lake Balinsasayao, Liguasan marsh, or the overflow lakes of the Agusan Valley. In the vicinity of Manila they are fished for too constantly to reach any very great size.
Dalag are very hardy and are able to survive conditions fatal to most other kinds of fishes. They are able to endure prolonged removal from the water, and during rains voluntarily make long journeys across wet grassy or muddy ground, or along tiny rills or wet paths. In this way they reach isolated pools and flooded rice fields,, although usually they reach the latter by following the irrigation ditches. Unobservant people, finding them in rice paddies which a few days before were dry and hard, have spread wide the delusion that they were buried in the sun-baked mud during the dry season or have rained down.
When the water has been drawn off or has evaporated until there remains but a pool of liquid mud, dalag are still able to survive for a long time, burrowing down in the mud for a foot or two; even after the surface of the mud has been caked over they will live as long as it is moist beneath.
Dalag take the hook readily, frogs being a particularly attractive bait. Large numbers are also taken in swamps and rice paddies by the aid of a conical woven trap, open at both ends, with the ribs projecting at the larger end for several inches. The person using it wades about, keeping a sharp lookout for bubbles of air which betray the presence -of a dalag beneath. When. these are seen the trap is plunged down into the mud over the spot where the bubbles were observed and, by feeling about with the hand in the inclosed space, the fish is forthwith caught. Although foreigners usually have a violent prejudice against eating dalag, they are really good food when properly prepared and have the great merit of being strictly fresh, since in most markets they are kept alive until sold, the market women having to stun them with a club before the customer can carry them readily.
Owing to their voracity, rapid reproduction, and quick growth, they play great havoc upon gaining entrance to ponds or preserves stocked with other fishes. Anyone engaging in the culture of other fresh-water fishes must be sure that there are no dalag left in the water to be stocked, and care must be taken that none can get in later.
This passage was originally published in 1924 as: Herre, A.W.C.T. - Distribution of the true freshwater fishes in the Philippines. II. Philippine Labyrinthici, Clariidae, and Siluridae . Philippine Journal of Science. 24(6):683-709.
|© 2001 - 2008 snakeheads.org||HOME of this page|