Louisiana plays host to 25 species
Most freshwater fishermen don’t give a lot of thought to the little fish in their bait bucket. They’re just shiners. Or to the glittery little fish flashing in the creek, river or lake — they’re just minnows.
But the word “minnow” takes in a lot of territory. The minnow family, Cyprinidae, is the largest family of freshwater fish in the world with roughly 2,400 species. The word “roughly” is used because Cyprinidae is a taxonomist’s delight.
Taxonomists are those scientists who study the evolutionary and family relationship between animals. They are divided into “lumpers” and “splitters.”
Splitters tend to want to create new species based on small details. Lumpers write off the small variations in a population to minor genetic variation and tend to combine multiple species into one.
So during any given day or week, depending on whose pitching is best, the number of species in the family could be different.
“Minnow” brings to mind “small,” like the little fish in the bait bucket. But not all minnows in Louisiana are small.
Common (German) carp, silver carp, grass carp, black carp and even the occasional goldfish (notice these are all introduced exotic species) are in the minnow family.
The minnows for sale at bait shops are all golden shiners, a species easy to grow in the quiet ponds of fish farms. But that wasn’t always the case. In the early 1960s, I would save my lawn-mowing money to buy shiners for crappie bait.
Often I had to wait at the bait stand until the seine crews came in from catching shiners in the wild. They caught a variety of shiners (Louisiana has 25 species), but by far the most common were what we called spot tail or blackspot shiners.
Officially named blacktail shiners (Cyprinella venusta), they are the most widespread and common shiner in the state, and can be identified by the prominent black spot located at the base of the tail.
Cyprinella means “small carp in Greek and venusta means “beautiful,” like the Roman goddess of love in Latin.
Only two other species have similar, although smaller, black spots. One has a black band down the side to go with the spot; the other is mainly found in the Ouachita River basin and lives in the quiet waters of oxbows and sluggish bayous.
The blacktail shiner almost always is found in swiftly flowing rivers and creeks with gravel and sand bottoms.
The blacktail shiner is a well-studied little fish (maximum size is 7½ inches, although few are over 4 inches long).
Most studied has been their tumultuous love life.
They are “crevice spawners,” which means they lay eggs into bottom crevices or under the edges of individual rocks in a gravelly bottom. Choice spawning sites are limited, and dominant males patrol the areas of the crevices to keep other males away.
Interestingly, the male makes solo runs along a crevice depositing his sperm before an eligible female even appears. Those actions seem to attract ready-to-spawn females that deposit their 140 to 460 eggs into the crevice holding the male’s sperm.
The female is closely watched by the male, which doubles back as soon as the female finishes to eat any eggs that failed to make it into the crevice.
While females are depositing eggs with a wiggle and a shake, smaller “sneaker” males dart in between the male and female to try to fertilize some eggs themselves — an action, not surprisingly, to which the dominant males take offense.
Dominant males that hold territory have to be constantly alert, even when a female isn’t present. The minute it turns its back, other males — both large and small — move in to deposit their own sperm in the crevice.
The competition produces a high level of aggression in males that, in turn, results in a shorter life span for males than females. Males defend their turf in four ways: swift assaults, chases, agonistic displays and fights.
In a swift assault, the male rams into the side of another male with its head, often turning the victim 90 degrees. Chases are just that: One male pursues another male beyond the contested territory.
Agonistic displays are shows of aggression, with each fish attempting to bluff the other into giving up. Two males swim in circles head to tail beside each other or parallel head to head, with their fins fully erect and their bodies rigid and quivering. Fights occur when neither fish backs down, and consists of violent ramming and head-butting that lasts longer than swift assaults.
While single male/single female spawnings are the norm, what one scientist called “disorderly episodes” also occur. He described these as “free-for-alls” of males and females massed at a spawning crevice, with individual females having to force their way to the crevice to spawn and no male able to guard the crevice.
Each female will spawn 20 to 46 times during the April-through-September spawning season. Researchers agree sound plays a role during spawning courtship, although they disagree on whether it is the males or the females who produce the pulses of grunts and knocks.
Typical lifespan of blackfin shiners is 4 to 5 years, with growth averaging slightly less than an inch a year. Females mature during the year after their first birthday, with all of them being mature by 1.6 inches long.
Major food items for the species are aquatic insect larvae, small insects such as termites and flies that have fallen into the water, small plant seed, algae, bottom sediment and detritus (the broken down remains of plants and animals).
Feeding is done during daylight hours.
They have been observed following bottom-rooting hogsuckers working their way upstream in swift-flowing riffle areas. Any food dislodged and not eaten by the suckers are taken by the shiners. Once they reach the head of the riffle, the entire group drifts downstream en masse to the riffle base to repeat the process.
Blacktail shiners are a very important food item for stream-dwelling predators such as spotted bass, and are excellent baitfish for anglers with enough energy to seine their own bait.
They offer little sport to fishermen except that rare breed called “micro-anglers.” The late Bread Snellings Jr. was one such fisherman. Former Times Picayune outdoor editor Bob Marshall managed to catch an incredible 489 different species of fish on hook and line.