Trachinotus blochii

Not to be confused with Florida pompano or Silver pomfret.

Background Information

Snubnose pompano
Conservation status
Least Concern  (IUCN 3.1)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Carangiformes
Family:	Carangidae
Genus:	Trachinotus
Species:	T. blochii
Binomial name
Trachinotus blochii (Lacépède, 1801)

The following paragraphs will discuss the golden pompano (Tranchinotus Bronchii) including the geographic range it inhabits, the environment in which it thrives, description of the species and the taxonomy.

Geographic Range

Spends from the Indian Ocean, the Red Sea and eastern Africa to the central Pacific Ocean. This includes northern Japan and as far south as the coast of Southern New Wales as seen in figure 1.

Environment

The golden pompano are pelagic fish associated with rocky reefs, coral reeds, as well as in shore habitats. Pelagic fish are associated with open seas. It is found in warm waters between twenty-five through twenty-nine degrees Celsius. They live in brackish waters. Brackish waters can be defined as waters with an increased amount of salinity than fresh water, however lower salinity levels than marine waters.

Description

Tranchinotus blochii, also called snub nosed dart, golden pompano, and golden pomfret, is an Asia Pacific species in the family Carangidae. The fish body shape can be described as fusiform body plane. The shape is streamlined or torpedo resemblance.

The body is also elongated helping to reduce drag as it is a burst swimmer. This is an adaptation to evade predators since drag is reduced. Another adaptation it has. to escape predators is the coloration description. Dorsal side is darker to camouflage into the environment if predated, or hunted, from above. Likewise, it is lighter in color on the ventral, or abdominal, side to blend into the environment if predated from below. Overall, it is tinted with yellow coloration as seen in figure 1 and 2.

Figure 1: Golden Pompano (Trachinotus bronchii) Identification

Figure 2: Anatomical features

Females are typically larger than the male Golden Pompano “females were found to be 17% larger than males after reaching 7 months of age...” [1] .  The length of the fish is in between around forty centimeters to about 110 centimeters.  The weight is around 3.4 kilograms. It is metabolically active and continuously swims thus needs a high energy diet.

Taxonomy

This is the science of naming, describing, and classifying the organism being studied. It can be group as followed:

Taxonomy

Classification	Name
Kingdom	Animalia
Phylum	Chordata
Subphylum	Vertebrata
Class	Actinopterygii
Subclass	Neopterygii
Order	Perciformes
Family	Carangidae
Genus	Trachinotus
Species	Tranchinotus blochii

According to alternative names includes buck-nosed trevally, dart, oyster cracker, snub-nosed dart, and snub-nosed swallow tail.

Behavior Ecology

Social Behavior

Juvenile pompano live in small schools, or groups, until they reach maturation. Adults live in solitary

Reproduction

The male and females are sexually dimorphic. Sexual dimorphism exhibits traits which differentiate males from females. These traits can be differences in size, color, and behavior between males and female individuals. Males and females have similar colors. However, they have different growth rates. Females typically mature quicker than the males and grow quicker.  There are also sex specific genes that aids in fish differentiation. Females have been observed with a heterozygous mutation. Males have been observed with a homozygous mutation.  

The life cycle starts off with females laying eggs in the offshore. The eggs are about one millimeter in diameter. Typically, they hatch within twenty-four hours. Metamorphism happens as they begin to lose the larvae shape in growing into their juvenile states. This takes about fifteen days to complete. Juveniles can be found offshore in sandy areas. The growth rate of the fish is fast.

Diet

The golden pompano has specialized pharyngeal plates designed to crush food such as shrimp, bivalves, etc. They are benthic feeders (figure 3) meaning that they feed on bottom dwellers. Their diet consists of proteins and fats essential to providing energy for their highly energetic lifestyle due to continuously swimming. Digestive tract is one of the shortest among similar species of fish thus suggesting more frequent feedings increases the growth rate of the fish. During the larvae stage of life, they feed on zooplankton. As they reach adulthood, they feed primarily on invertebrates

Figure 3: Benthic Feeding of Pompano

Competition

Larger fish, marine mammals, and birds like to predate upon Trachinotus blochii. It causes competition among patches of areas. These patches can have resources that the pompano can use. The pompano evolved evasion as a response to being predated.

Human Interaction

Figure 4: Human Consumption of Pompano

Golden pompano is very nutritious and highly sought (figure 4). Consumer demand is high although the wild supply of them is low. There is currently research being done to increase hatchery fish survivability.

Conservation Status

Five trachnotus species ( Trachinotus anak, Trachinotus blochii, Trachinotus mookalee, Trachinotus goreenisi, Trachinotus ovatus) were subjects observing global change impact of the distrubution of the fish. This study concluded that these species are adaptable and predicts expansions of the geographic range more so into the coasts of China. ²  These species are least concerned on the endangered species list.  

However, nocardiosis threatens the population. In return, human harvesting and consumption rates can be affected also. Nocardiosis is a bacterial infection. Symptoms includes visible lesions and eroding skin. Degradation of the gills can be apparent. Immunocompromised people could catch the bacteria and become ill. They can show respiratory symptoms similar to colds such as cough, hard time breathing etc.