Goonch catfish

Identifying it

No diagnosis accompanies this species in the file consulted. No ray counts, no colour, no proportion, nothing that would key it against the other members of its genus. What is available is an outline, and it comes from the catalogue entry on this page: a heavy body flattened underneath, a wide mouth carrying sharp teeth.

The family placement carries more information than the outline does. Bagarius sits in the Sisoridae, the catfishes of the fast rivers of southern Asia, and everything else on this page is consistent with that address rather than with any published description of this particular fish.

The water it needs

The water chemistry is the one part of the file given in numbers, and it is unexpectedly precise for a species with no diagnosis at all: pH 6.5 to 7.8, hardness 12 to 30, temperature 18 to 25 degrees.

Taken together those three figures describe a hard, near-neutral, cool river. Hardness in that band is water that has run over rock and taken minerals out of it, and a ceiling of 25 degrees is low for the latitudes involved. Neither number belongs to a warm lowland floodplain. Both belong to a river fed off high ground, which is why this animal and the Himalayan foothills are named in the same breath everywhere.

Two further entries widen the picture. The species tolerates brackish water, and it moves within the freshwater network without going to sea. Between them those allow it the whole length of a river system, from broken rock in the upper sections down to the reaches that taste of salt.

How to catch it

The file classes the fish as benthopelagic rather than demersal, which is a small distinction with a practical edge: it works the bed and the water above it, and it is not permanently pinned to the bottom.

The places listed for it are all edges of current rather than current itself — the eddy below a rapid, the slack behind a boulder, the narrow chute between rocks, the deep pool at the foot of broken water. Every one of those is somewhere the flow loses speed without stopping, which is also where whatever the river is carrying comes to rest.

That settles the presentation. Bait goes in heavy and is allowed to settle at the bottom of the slack, put in above the seam if anything, so that it finishes where the current would have deposited it anyway. Holding a bait out in the fast water is fishing the wrong side of the line.

The species supports a small commercial fishery and is also taken deliberately by anglers, so two kinds of pressure fall on the same populations.

Conservation

The recorded decline is attributed to the level of exploitation, and the file contains almost nothing else that could be used to manage it. No spawning season, no fecundity, no diet, no age. A species known only through what is landed can only be governed by what is landed.

Two entries in the environment line make that worse than it sounds. The fish moves inside the river network, and it tolerates brackish water at the bottom of it. A population defined that way is one unit spread across an entire drainage, so anything that divides the drainage divides a stock nobody has counted.

The missing longevity figure is the last problem. Without it there is no way to estimate how long a stripped reach takes to refill, and therefore no basis for saying whether a recovering stretch is actually recovering or merely still holding the fish that were left behind.

Other names

Goonch is a name from the Indian subcontinent that the European languages took whole instead of translating, and English doubles it — goonch catfish — because the word alone carries no meaning for an English reader.

That empty word has been filled by something else. In English-language television and print this fish has acquired a reputation as a man-eater, and the reference file answers the question directly, in its own vocabulary: under threat to humans it is entered as harmless. That is the only published statement on the point, and it contradicts the whole of the popular account.