The striped bonito (Sarda orientalis) is a medium-sized predatory scombrid fish in the tribe Sardini, closely related to mackerels and tuna. It lives in the Indo-Pacific and East Pacific Ocean, generally in near-coastal waters. It is caught by fishermen for food, and itself feeds mostly on creatures from the seafloor.
Most of the true bonitos are in the genus Sarda, though the striped bonito is the only kind found in the Gulf of Fernandez. Other genera of bonito include Cybiosarda, Gymnosarda, and Orcynopsis. The term “bonito” in Japanese cuisine refers to the skipjack tuna or katsuo (Katsuwonus pelamis), and otherwise is sometimes used to refer generally to any various scombrid fish related to but smaller than tuna.
Description
The striped bonito grows to 40 inches in length, and is a perciform fish. It has 17 to 18 dorsal spines and 14 to 16 anal soft rays. The dorsal side of its head is a lustrous metallic blue, and the rest of its body is silvery with some darker horizontal striping. Its first dorsal fin is longer than its head and almost connects to the second dorsal fin. The caudal peduncle is very narrow, with six to eight small finlets found on both the top and bottom.
Bonitos are rich in the amino acid lysine, making them a means by which piscivorous dinosaurs could avoid dying due to InGen’s lysine contingency. They also travel into relatively shallow water to feed on crustaceans, during which time the dinosaurs could easily feed on these fish.
Growth
As with most of their relatives, bonitos start out life as planktonic larvae. They gradually develop into adolescent and then adult fish. Most species of bonitos grow reasonably quickly, reaching roughly a kilogram in a few months.
Sexual Dimorphism
No sexual dimorphism is known in the striped bonito.
Habitat
Preferred Habitat
The striped bonito inhabits near-coastal waters up to 550 feet deep, but may venture into water as little as three feet deep in search of food.
Natural range
This fish inhabits the Pacific Ocean, ranging from the Indo-Pacific into the East Pacific including the Gulf of Fernandez. It normally lives in waters off coastlines, and is frequently found near islands such as the Muertes Archipelago. On larger islands such as Isla Sorna, as well as mainland areas, it will sometimes venture into rather shallow water to feed on crustaceans living just off beaches and in estuaries.
Introduced
The striped bonito has not been introduced to waters outside its native range. It is not commonly bred in mariculture, so it seldom appears in captivity either.
Behavior and Ecology
Activity Patterns
Bonitos maintain activity throughout the full daily cycle; most fish do not truly sleep. In 2001, a shoal was observed in a tidal river during the early hours of the morning. The striped bonito normally only ventures into shallow water to feed, suggesting that the shoal had moved into the river in search of food.
Diet and Feeding Behavior
Striped bonitos normally inhabit the ocean, but venture into shallow water to feed. Their diet consists of smaller fish, crustaceans, and small squid.
Social Behavior
Bonitos are shoaling fish, traveling in groups for protection; they may shoal with other types of related fish such as tuna. Despite this, they are not particularly social and do not form attachments with others of their kind. Shoals are capable of group coordination when evading predators, which is observed by Dr. Alan Grant and Eric Kirby. This behavior, called “flashing,” involves the entire school rapidly changing direction in order to reflect light off of their silvery scales to confuse predators and help the fish escape.
Reproduction
Breeding occurs with the monsoon season. Bonitos, as with many fish, spawn by releasing gametes into the water column, and the larvae that develop drift as plankton until they grow large and strong enough to swim on their own. They do not practice parental care.
Communication
Like the majority of fish, bonitos are not capable of vocalizing and have little in the way of communication other than movement.
Ecological Interactions
This is a predatory fish, but is only midway up the food web. It feeds on crustaceans from the seafloor, and on various small fish and squid in mid-water; its prey items are themselves either carnivores or scavengers. Bonitos are subsequently preyed upon by bigger animals, including marine mammals, larger fish, large squid, and piscivorous birds.
When in shallow water on Isla Sorna, bonitos are at risk of being preyed upon by piscivorous dinosaurs. A school of bonitos in 2001 was seen fleeing a Spinosaurus, suggesting that this animal preys on them. The bonitos “flashed” the spinosaur twice while near the surface, a behavior which helps many kinds of fish escape danger. Other predators which have been confirmed in this same channel include Ceratosaurus and Pteranodon, both of which are believed to feed on fish. These could also be potential threats to native bonitos. The range of Baryonyx on Isla Sorna is not confirmed, but these dinosaurs are also piscivorous and could prey on bonitos.
In Eric Kirby’s account Survivor, he describes a Pteranodon hunting silvery fish in the ocean which may have been bonitos. A cooked fish he describes later attracts a group of Compsognathus and an unidentified medium-sized animal, suggesting that other carnivores may opportunistically eat fish such as bonitos if they get the chance.
Cultural Significance
Symbolism
While the bonito may not be a common feature in art, its name reflects the appreciation fishermen have had for its appearance for generations. The name “bonito” comes from Spanish, originating around the 16th century; it means “pretty” or “lovely.”
In Captivitiy
The Atlantic and South Pacific bonitos (Sarda sarda and Sarda chiliensis chiliensis, respectively) have been raised and successfully spawned in recirculating aquaculture systems. As of 2011, the Atlantic bonito was being bred for domestication by the Murcian Oceanographic Centre of the Spanish Institute of Oceanography in Spain. The ultimate goal of the project is to domesticate the related bluefin tuna, but the smaller bonito is used as a model species. As a marine fish, it needs to be kept in a saltwater environment, which can be intensive and requires constant monitoring of the water chemistry and oxygen content. Wild-caught fish may become disoriented in captivity and collide with the walls of their containment, which can injure them.
In 2021, the Pacific bonito was also cultured by researchers after being caught off the Chilean coast. Researchers have found that this species is best kept at three fish per cubic meter of seawater. The fish caught for this project produced viable offspring after 14 months. They naturally feed on small aquatic animals as prey, so they must be acclimated to eating aquaculture feeds; it is best to start them with a diet of live and prepared fish, crustaceans, or squid and wean them onto a diet of prepared food fairly quickly. This ensures they will rebound from the stress of being transported from the sea, settling into their new habitat with minimal health issues.
Science
Bonitos are usually smaller and easier to keep than tunas, making them candidates for scombrid research. Studies using bonitos as models can be applied to tunas. Currently, most of the research using bonitos involves the Atlantic and Pacific species and focuses on how to keep them thriving in captivity as to enable aquaculture farming.
Politics
While they are subject to national, state, and local fishing regulations, bonitos are considered common fish and restrictions on catching them are usually not particularly stringent. At the moment there are no major ocean policy issues that specifically concern bonitos.
Bonito cannot legally be marketed as tuna in all countries, though this varies from one nation to another.
Resources
For hundreds of years the bonito has been caught for food by humans on coastlines of both the Atlantic and Pacific Oceans; the name “bonito” dates to at least the 16th century. Its meat is moderately fatty, dark in color, and firm. Younger fish usually have lighter meat often compared to skipjack tuna, and may sometimes be used as a replacement for said tuna (especially for canning). Bonito meat is commonly grilled or baked.
Dishes utilizing the bonito include varieties of katsuobushi called “bonito flakes,” which use the meat of younger bonitos, and lakerda. Bonito flakes are simmered, smoked, and fermented, common in Japan. Their relatives in the Atlantic are the main source of lakerda, which is pickled and is served in the Balkans and the Middle East around the Mediterranean Sea.
As well as being eaten, fishing for bonitos is a form of entertainment since this is a muscular fish that puts up a fight when on the hook. While not the largest sport fish, it is still quite prized.
Safety
You are unlikely to be attacked by a bonito. It is a medium-sized and strong fish, so the usual care should be taken when it is hooked or being reeled in while fishing. Proper preparation of the meat is essential to avoid parasitic infection, as is the case with all fish.
Behind the Scenes
The shoal of bonitos which appears in Jurassic Park /// is portrayed using digital effects, rather than making use of live-action fish. It can be assumed that the striped bonito (Sarda orientalis) was the species witnessed in the film by Dr. Alan Grant, as Isla Sorna is within the native range of this species according to FishBase. No other bonito species are found in this area.
