Pacific bumper

Chloroscombrus orqueta is a fish of the family Carangidae, described in 1883 from specimens collected in Panama ^[1],[2]. It is a small fish with an oval, strongly compressed body that schools in coastal waters of the eastern Pacific, from southern California to Peru ^[3]. Its juveniles have been found beside jellyfish, and the species turns up in the bycatch of shrimp trawling ^[4],[5]. Its global category on the IUCN Red List is Least Concern ^[6].

Jordan and Gilbert described the species in 1883 from specimens gathered by Gilbert in Panama, and the name orqueta is the one the local fishermen there used for the fish ^[1]. The authors treated it as the Pacific counterpart of Chloroscombrus chrysurus, the Atlantic species of the same genus ^[1]. For Peru, FishBase records the names «pardo», «chuyes», «citarita» and «parvo» ^[3].

The body is oval and strongly compressed, with sharp edges; the belly profile curves more than the back, the head is small and somewhat pointed, and the mouth is small and very oblique, with a projecting lower jaw ^[1]. The head is almost naked and the body bears well-developed scales; the jaw teeth are very small, and the caudal fin is widely forked, with the upper lobe slightly longer than the lower ^[1].

In life the back is green with blue reflections and the sides and belly are silvery white; there is a black blotch on the upper angle of the gill cover and another, square one on the back of the tail, over the bases of the upper caudal rays ^[1]. The fins are yellowish, with the dorsal and anal edged in black and the tip of the upper caudal lobe black ^[1]. According to FishBase it reaches 30 cm total length, though 18 cm is usual ^[3].

Similar species

• Chloroscombrus chrysurus: According to the authors, Chloroscombrus chrysurus, of the Atlantic, has essentially the same proportions, fin rays and colouring (that of Chloroscombrus orqueta is somewhat darker), but it is told apart by a much shorter curve of the lateral line and by lacking the marked armature of the tail stalk: Chloroscombrus orqueta has a distinct keel with enlarged, bony lateral-line scales, whereas in the other they differ little from the rest ^[1].

It lives in the eastern Pacific, from San Pedro, in southern California, to Peru, including the Gulf of California ^[3]. A study of shrimp bycatch lists it with an affinity from the San Diego to the Panamic province ^[5], and defines the latter as extending south from El Salvador to around Cabo Blanco, in northern Peru ^[5].

FishBase describes it as a fish of marine and brackish water whose adults school in coastal waters, including mangrove lagoons ^[3]. In the Gulf of California it was recorded in the 2004-2005 shrimp-fishing season, in sampling done between 4 and 137 m depth on the shelf of Sonora, Sinaloa and Nayarit ^[5].

In Bahía de La Paz, between 2008 and 2011, 71 specimens of this species were collected; the largest measured 60 mm total length and the smallest fish of the three species in the study 8 to 10 mm, and they were post-flexion larvae and early juveniles ^[4]. The authors cite that fish associated with floating objects are mostly juveniles and that, beside jellyfish, they may gain protection from predators and access to planktonic food ^[4].

According to FishBase, the estimated trophic level is 2.5, based on diet studies, and the species makes grunting sounds when caught ^[3].

In Bahía de La Paz, in the Gulf of California, this species was the most abundant of the 3 carangids that came up incidentally with the cannonball jellyfish Stomolophus meleagris: 71 of the 96 fish, or 74 % ^[4]. It was found in 2009, 2010 and 2011, and the authors note that it was present in different seasons and years ^[4].

The authors state that the reproductive cycle of this species and of Caranx caballus has been reported over most of the year, so larvae and juveniles can be present almost year-round, and that their abundance could depend on other factors such as plankton biomass ^[4]. In shrimp trawling in the Gulf of California it was classed as an abundant species, meaning a relative abundance above 1 % of the individuals sampled ^[5].

Its global category on the IUCN Red List is Least Concern ^[6]. FishBase states that the assessment dates from 30 April 2008 and that the species' vulnerability to fishing is low, with a value of 24 out of 100 ^[3].

FishBase states that it is used commercially on a small scale and sold fresh, salted and fried ^[3]. In the Gulf of California it is part of the bycatch of the industrial shrimp fishery, in which fish made up 70 % of the catch ^[5].