Blackfin Wolf Herring

Blackfin wolf-herrings lack many natural predators, and its mostly silver body acts as camouflage. Humans <>) are the primary predator of this species, which are used for food and for bait.

Known Predators:

• Humans Homo sapiens

Anti-predator Adaptations: cryptic

Fish of the suborder Clupeoidei, including blackfin wolf-herrings, have a phenomenal ability to hear due to two pairs of air bubbles inside their inner ears. Some members of this suborder can even detect ultrasonic frequencies. Pacific herrings (Clupea pallasii pallasii), for example, alter their feeding and schooling behaviors when sounds of toothed whales are imitated in a controlled environment. Some similar species of herring not only react to, but also produce high frequency sounds by releasing air bubbles. Because they feed primarily during the day, members of this genus g. Chirocentrus are also thought to utilize sight to hunt.

Perception Channels: visual ; tactile ; acoustic ; vibrations ; chemical

Blackfin wolf-herrings are not currently listed at risk by the IUCN, CITES, or the US Federal List. Abundant fishing of this species is not currently know to drastically affect populations.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

Intra-ovarian eggs of blackfin wolf-herrings reach maturity at 50 to 65 millidarcies (measurement of permeability) and are then released by the female. Males typically mature at smaller sizes than females. The growth rate remains constant in males until they reach 30 cm and in females until they reach 40 cm, after which there is a marked decline in growth rate.

Despite stories of fisherman being bitten by blackfin wolf-herrings, currently there are no known adverse effects of Chirocentrus nudus on humans. These accidental bites are believed to result from mishandling of captured fish.

Negative Impacts: injures humans (bites or stings)

Blackfin wolf herrings are an important part of the fishing industry and make up a large percentage of catches along the Pacific coastlines. Fishery reports from Tanzania, Pakistan, India, Thailand, Indonesia, Maylasia, Singapore and the Philippines recorded catches of the genus Chirocentrus totaling 50,083 tons in 1983. As a gamefish, wolf-herrings are targeted by many fisheries in the Indian Ocean and western Pacific Ocean. They are typically caught using gillnets, seines, shawls and traps. Blackfin wolf-herrings are marketed fresh, frozen, or dried and salted. Blackfin wolf herrings are also used as bait for other trophy fish.

Positive Impacts: food

Blackfin wolf-herrings are common predators of sardines. They also act as host to marine leeches, Nerocila phaiopleura, which attach at the branchial/shoulder region of a host fish. Leeches do not cause harm to the fish while feeding. As the leech releases from its host, however, it leaves small skin lesions at its point of attachment. These lesions allow easy access for pathogenic microbes and infections like vibriosis. Vibriosis is an infection caused by a group of bacteria from the genus g. Vibrio.

Commensal/Parasitic Species:

• Marine leech Nerocila phaiopleura

As a carnivorous fish, blackfin wolf-herrings prey mainly on other members of the order Clupeiformes, as well as members of the class Cephalopoda (octopus and squid). Sardines, however, are preferred prey of this species, particularly Sardinella brachysoma and Sardinella gibbosa. Juveniles also display this carnivorous behavior, feeding on small shrimp, post-larvae, and early juvenile fish. The diet of blackfin wolf-herrings is seasonally consistent. As they feed primarily during the day, members of this genus g. Chirocentrus are thought to rely on sight to hunt.

Animal Foods: fish; mollusks; aquatic crustaceans

Primary Diet: carnivore (Piscivore )

Blackfin wolf-herrings, Chirocentrus nudus, are found throughout the Indian Ocean, ranging from the eastern shores of Africa to the Solomon Islands. They can be found as far north as southern Japan and as far south as northern Australia.

Biogeographic Regions: indian ocean (Native ); pacific ocean (Native )

Blackfin wolf-herrings prefer warm coastal waters, often in inland areas. They inhabit brackish and marine waters up to depths of 120 m. This species, however, is most commonly found in turbulent waters at depths from 9 to 28 m. Blackfin wolf-herrings also frequent coral reefs, which are potential hunting grounds.

Range depth: 0 to 120 m.

Average depth: 9 to 28 m.

Habitat Regions: saltwater or marine

Aquatic Biomes: reef ; coastal ; brackish water

Longevity of blackfin wolf-herrings is not well documented. Age of blackfin wolf-herrings can be estimated through a model of growth rate for this species, which uses measures of length (to the caudal fork) and of a portion of a bone called the otolith. Due to this technical procedure, relatively few individuals have been aged. Most members of this species aged using this method were 4 to 6 years of age, though some were as old as 13 years of age.

Range lifespan
Status: wild: 6 to 13 years.

Typical lifespan
Status: wild: 2 to 13 years.

Average lifespan
Status: wild: 6 years.

Blackfin wolf-herrings are narrow elongated fish, so named for the black markings on the upper part of the dorsal fin and the wolf-like canines protruding from their mandible and premaxilla. These black markings set this species apart from its closest relative Chirocentrus nudus, whitefin wolf-herrings. The wide mandible of blackfin wolf-herrings appears to point almost directly upward when their mouth is closed. Members of the family Chirocentridae have been characterized as long herrings. On average, the fork lengths (distance from tip of lower jaw to the fork of caudal fin) of most blackfin wolf-herrings range from 14 to 71 cm. Some blackfin wolf-herrings have been recorded at over 1 meter long. Members of this species generally weigh between 170 and 1200 g.

Range mass: 170 to 1200 g.

Average mass: 800 g.

Range length: 3 to 120 cm.

Average length: 70 cm.

Other Physical Features: heterothermic ; bilateral symmetry

Sexual Dimorphism: sexes alike

Blackfin wolf-herrings reproduce by spawning, though little information is available regarding specific mating systems of this species. Mating systems are likely similar to those of other members of the suborder Clupeoidei. Clupeoids generally disperse pelagic eggs, which are fertilized and then drift through the current or adhere to substrate.

Little information is available regarding the breeding of blackfin wolf-herrings. Like other members of the order Clupeiformes, blackfin wolf-herrings are believed to breed once annually, producing many offspring. Reports of spawning activity varies by location. Spawning generally occurs from April to June, but in some areas spawning occurs as late as October. In some cases around the Rameswaram Islands, spawning has been reported to begin in December.

Breeding interval: Blackfin wolf-herrings breed once annually.

Breeding season: Blackfin wolf-herrings generally breed between April and October

Average age at sexual or reproductive maturity (female): 1 minutes.

Average age at sexual or reproductive maturity (male): 1 minutes.

Key Reproductive Features: seasonal breeding ; fertilization (External ); oviparous

As with all spawning fishes, blackfin wolf-herrings do not demonstrate investment in their offspring post-fertilization.

Parental Investment: no parental involvement

The slightly shorter pectoral fin (11 to 13% of standard length; cf. 13 to 18%) and the black marking of the upper part of the dorsal fin are the only satisfactory characters separating this species from C. nudus; there is also some black on the anterior part of the anal fin. Variations in body depth may represent sexual dimorphism, but this needs study.

Probably throughout the warmer coastal waters of the Indo-Pacific, from the Arab Gulf, Red Sea, east African coast south to Durban, eastward to Japan, the Philippines and south to northern Australia. However, it is not known to what extent C. nudus may contribute to these records.

To about 100 cm of standard length.

Pelagic,inshore fishes.Feeds mainly on small fishes, but perhaps also crustaceans, etc. No precise information on breeding.

Separate statistics for Chirocentrus (almost certainly including a proportion of C. nudus) are reported by Tanzania, Pakistan, India, Thailand, Indonesia, Malaysia, Singapore and the Philippines, with a total of 50 083 t in 1983. The catches in Palk Bay and around Rameswaram I in the Gulf of Mannar (southern India) are the only ones where the two species of Chirocentrus were positively separated (Luther, 1968); C. dorab contributed only 20% to the catch, the rest being C. nudus, caught with gillnets, seines, shallow trawls and traps. The total catch reported for this species to FAO for 1999 was 13 077 t. The countries with the largest catches were Thailand (10 800 t) and Pakistan (2 266 t). Marketed fresh or frozen.The total catch in 1996 was 11 873 t (Thailand 10 292 t and Pakistan 1 580 t).

Diagnosis: The slightly shorter pectoral fin, 11-13% of standard length, and the black marking of the upper part of the dorsal fin are the only satisfactory characters separating this species from Chirocentrus nudus; there is also some black on the anterior part of the anal fin (Ref. 188).Description: With numerous dagger-like teeth (Ref. 37816). Lower gillrakers 12-16 (Ref. 6595). Pectoral fin shorter than distance between eye centre and hind border of gill cover, 11-13% of standard length; dorsal fin with 4-5 unbranched and 12-14 branched rays; anal fin with 3-4 unbranched and 26-32 branched rays; pectoral fin with 1 unbranched and 13-15 branched rays; pelvic fin with 1 unbranched and 6-7 branched rays (Ref. 2871, 6595, 30573). Scales numerous, small, usually lost (Ref. 6595, 37816). Belly without scutes (Ref. 6595).Colouration: Silvery; back bright blue, fading to grey; flanks bright silver (Ref. 37816).

Camallanus Disease. Parasitic infestations (protozoa, worms, etc.)

Acanthocolpus Infestation 1. Parasitic infestations (protozoa, worms, etc.)

Acanthocolpus Infestation 2. Parasitic infestations (protozoa, worms, etc.)

Megamicrocotyle Infestation. Parasitic infestations (protozoa, worms, etc.)

Nybelinia Disease. Parasitic infestations (protozoa, worms, etc.)

Camallanus Infection 4. Parasitic infestations (protozoa, worms, etc.)

Amphidromous. Refers to fishes that regularly migrate between freshwater and the sea (in both directions), but not for the purpose of breeding, as in anadromous and catadromous species. Sub-division of diadromous. Migrations should be cyclical and predictable and cover more than 100 km.Characteristic elements in amphidromy are: reproduction in fresh water, passage to sea by newly hatched larvae, a period of feeding and growing at sea usually a few months long, return to fresh water of well-grown juveniles, a further period of feeding and growing in fresh water, followed by reproduction there (Ref. 82692).

Dorsal spines (total): 0; Dorsal soft rays (total): 16 - 19; Analspines: 0; Analsoft rays: 29 - 36

Occurs in inshore waters of the continental shelf (Ref. 75154).

Occurs inshore, including brackish waters (Ref. 12743), from the shore to a depth of about 120 m (Ref. 30573). In Australia, it was reported in water temperatures of 26.0-29.0 °C (Ref. 4959). It feeds mainly on small fish and crustaceans (Ref. 188, 30573). Voracious predators of small schooling fishes, e.g. herrings and anchovies (Ref. 37816). Marketed fresh, frozen or dried and salted.

fisheries: commercial; gamefish: yes; bait: usually

分布於印度-太平洋暖水海域，西起紅海、非洲東部，東至所羅門群島，北至日本南部，南至澳洲北部。臺灣四周海域及澎湖均有產。

一般利用流刺網或一支釣等漁法捕獲。但因為魚體瘦薄，肉質較少，因此並非主要經濟魚種，市場上亦較少見。

體側扁而狹長，背緣近平直；腹緣尖但無稜鱗，外觀狀似短刀，故而被稱為寶刀魚。頭短，背部平。吻中等長。眼小，有脂性眼瞼。口裂大，向上陡斜，下頜突出於上頜；上頜骨末端向後延伸不及前鰓蓋骨上；上頜骨前端和下頜有銳利的犬齒，上頜兩側及腭骨均有細齒。鰓耙數3+14。體被細薄圓鱗，極易脫落；背鰭和臀鰭基部有發達之鱗鞘；胸鰭和腹鰭基部具腋鱗；尾鰭基部亦被細鱗。背鰭、臀鰭位於魚體之後半部，背鰭軟條16；臀鰭基底長，軟條30-34；尾鰭深叉。體背青綠色，腹側銀白色。各鰭淡黃色或淡色；尾鰭具黑緣。

近沿海表層洄游魚種，有時會進入汽水域。喜分散游動，不集結成群。肉食性，主要以小型魚類為主食，偶食甲殼類。

The dorab wolf-herring (Chirocentrus dorab) is a fish species from the genus Chirocentrus of the family Chirocentridae. It is a coastal fish, silvery below and bright blue above. It is found in both marine and brackish or estuarine waters, feeding on smaller fish and possibly crustaceans. Chirocentrus is from the Greek cheir meaning hand and kentron meaning sting. Dorab is from the Arabic language word darrab (ضرّاب) and the word is probably a corrupted form of durubb (دُرُبّ) the name for goldfish in Arabic. It has another Arabic name, lisan (لسان) which means tongue.

Occurs inshore. In Australia, it was reported in water temperatures of 26.0-29.0 °C (Ref. 4959). Feeds mainly on small fishes, but perhaps also crustaceans. Marketed fresh, frozen or dried and salted . Widely distributed in the Indian and Pacific Oceans .