Longnose gar

Gar present three separate problems and the third one is unique in this catalogue.

THE BEAK. A long narrow jaw lined with many fine needle-sharp teeth, used to seize prey sideways. It punctures rather than cuts, the punctures are numerous, and a gar shakes its head. Hands do not approach the mouth: long pliers, and a gloved grip well behind the head.

THE ARMOUR. Gar are covered in hard, interlocking, enamel-like ganoid scales that are genuinely difficult to penetrate — historically used as arrowheads and abrasives. They are also sharp-edged. A hand run along a gar removes skin, and a fish thrashing against a bare forearm does the same. This armour is also why gar are hard to hook and why rope lures exist for them.

AND THE ROE IS TOXIC. Gar eggs are poisonous to humans and to many other animals — a real and documented toxicity, not a folk belief. A gar being prepared for the table must have the roe discarded and kept away from anybody who might eat it. This is the clearest case in the catalogue of a fish where the handling advice extends into the kitchen.

THE FISH IS OTHERWISE ROBUST. Gar are air-breathers with a vascularised swim bladder, tolerate poor water and handling far better than most fish, and survive release readily.

AND THE LEAD POINT. Gar are frequently fished with heavy terminal tackle in freshwater systems where lead restrictions may apply, and the species' longevity means bioaccumulation is a live consideration for anybody eating large individuals. Both are local questions worth asking.

Longnose gar share their habitat with bowfin and arrived at it along a separate evolutionary route, which makes the pair a useful illustration of what that habitat actually demands.

THE WATER IS THE SAME. Warm, slow, shallow, vegetated: backwaters, oxbows, sluggish river reaches, reservoir margins and weedy lakes across a large part of eastern and central North America. Gars tolerate low oxygen, high temperature and turbidity that exclude most predatory fish, and they also tolerate brackish water — longnose gar occur in coastal and estuarine situations well down the salinity gradient, which extends the range considerably.

THE SOLUTION IS THE SAME AND SEPARATELY EVOLVED. Gars possess a vascularised, alveolated gas bladder that functions as a lung, and they surface to gulp air — visibly and frequently, which is how they are usually spotted. As with bowfin, this converts oxygen-poor water into an uncontested niche.

THE HUNTING SHAPE IS WHERE THEY DIVERGE. A gar is an extremely elongate fish with a long, narrow, tooth-lined beak, and it hunts by lying almost motionless near the surface and striking sideways with a rapid sweep of the head. That works in the upper water among weed and structure rather than from deep cover, so gars are frequently seen basking near the surface in a way a bowfin is not, and they hold in the top of the column where an air-breather has least to lose.

THE ARMOUR IS PART OF THE HABITAT STORY. Gars are covered in thick, interlocking, enamel-coated ganoid scales forming a rigid protective sheath. That is heavy and it costs flexibility, and it buys near-immunity from predation — which is a reasonable trade in shallow warm water shared with large predators, and part of why gars persist where they do.

AND THE SPAWNING TIES THEM TO FLOODED MARGINS. Gars spawn over vegetation in shallow warm water, and the eggs are toxic to many potential predators, which is a further adaptation to a habitat with nowhere to hide. River channelisation and floodplain disconnection remove exactly that spawning habitat, which is the principal pressure on the group.