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Triglidae

life science Maturity 5-7 Next article →

Triglidae is a family of bottom-feeding fish known as gurnards or sea robins. These ray-finned fish live in both temperate and tropical seas across the globe. They are classified as scorpaenoid fish, which describes their general body type. Scientists group them in different ways depending on their research. Some experts place them in the order Scorpaeniformes. Other authorities believe they belong in the order Perciformes. This disagreement happens because of how different species are related to one another.

One of the most amazing things about gurnards is how they move. They have three specialized structures on each side called walking rays. These rays are actually modified fin-rays from their pectoral fins. During their development, these rays separate from the rest of the fin membrane. They possess unique anatomy and specialized muscle divisions. This allows them to use the rays for underwater locomotion along the seafloor. The rays also help them find food through a process called chemoreception. This is a way of "tasting" the environment using highly sensitive senses. They can detect amino acids that are common in marine invertebrates.

Tub Gurnard, Gard, Languedoc-Roussillon, FR imported from iNaturalist photo 413989311
Tub Gurnard, Gard, Languedoc-Roussillon, FR imported from iNaturalist photo 413989311

Physical features make gurnards easy to identify in the wild. Their heads are bony and often resemble a protective casque. Most species have a snout with paired rostral projections. These projections can have spines and make the snout look two-lobed from above. They also have a very solid skull and sometimes possess armored plates on their bodies. A unique feature is the drumming muscle. This muscle beats against the swim bladder to create sounds. This action produces a croaking noise similar to a frog. This sound is why they are called gurnards.

Chelidonichthys lucerna Natural History Museum University of Pisa P 433
Chelidonichthys lucerna Natural History Museum University of Pisa P 433

There are many different types of gurnards within this family. The family is divided into 14 different genera and four subfamilies. This includes about 170 different species. The subfamilies include Prionotinae, Pterygotriglinae, and Triglinae. Some scientists also consider the subfamily Peristediinae to be part of the Triglidae family. The Prionotinae are considered the basal grouping in the family. The Triglinae are seen as the most derived group.

History shows how our understanding of these fish has changed. The French naturalist Constantine Samuel Rafinesque first described the Triglidae family in 1815. Later, in 1883, Jordan and Gilbert designated a specific species as the type for the family. This species is Trigla lyra. Linnaeus had actually described this fish much earlier, in 1758. The name "Trigla" comes from a classical name for the red mullet. Early researchers like Artedi thought gurnards and red mullets were the same. They noticed both fish were red and made sounds. However, Linnaeus realized they were different and gave them separate classifications.

Size and habitat vary greatly among the 170 species. The smallest is the spotwing gurnard, known as Lepidotrigla spiloptera. The largest is the tub gurnard, or Chelidonichthys lucerna. Most species are around 30 centimeters in length. In many species, the females grow larger than the males. Gurnards are carnivores that mainly eat crustaceans. They are also opportunistic predators that eat mollusks and other small fish. They live on the bottom of the ocean down to depths of 200 meters. While adults prefer deeper water, juveniles tend to stay in shallower areas.

Humans have a long history of interacting with gurnards. They are often used in cooking because they have firm white flesh. In France, they are a common ingredient in the dish bouillabaisse. In the past, British fishermen often caught them as bycatch and threw them away. However, their popularity has grown as other fish became more expensive. Between 2007 and 2008, the wholesale price in some areas rose from £0.25 to £4 per kg. Sales increased tenfold by the year 2011. Today, they are found in fish markets in the United States as well.

Chelidonichthys lucerna filetti burrro e salvia
Chelidonichthys lucerna filetti burrro e salvia
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Spiny red gurnard - Tokyosealifepark -...
File:Tub Gurnard, Gard, Languedoc-Roussillon, FR imported from iNaturalist photo 413989311.jpg
Tub Gurnard, Gard, Languedoc-Roussillon,...
File:Chelidonichthys lucerna Natural History Museum University of Pisa P 433.jpg
Chelidonichthys lucerna Natural History...
File:Chelidonichthys lucerna filetti burrro e salvia.jpg
Chelidonichthys lucerna filetti burrro e...
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