Northern brown shrimp - Farfantepenaeus aztecus

 

brown shrimp

 

Diagnostic characters: Carapace smooth. Rostrum armed with usually 8 or 9 teeth on dorsal margin and 2
teeth on ventral, its tip moderately short (1/4 or less the length of rostrum); adrostral sulcus and carina long,
extending almost to hind margin of carapace, sulcus wide posteriorly; postrostral carina well developed
as far back as adrostral sulcus, with a deep median sulcus throughout its length; gastrofrontal carina present.
Dorsolateral sulcus on last abdominal segment well defined and broad, ratio of height of dorsal
keel to width of sulcus often less than 2.25.Antennae short, about 1.4 times the body length.Petasma with
short distomarginal projections, distal folds not forming auricles, apices of ventral costae tightly
joined to adjacent membranous portion; free border of costae unarmed, attached border with 2 or 3 series
of closely set teeth. Thelycum with lateral plates, their anteromedian angles divergent; posterior
process armed with a median crest bifurcate anteriorly (Y-shaped) and exposed. Colour: often brown,
sometimes with an orange or yellowish tinge, occasionally reddish or greenish; pereiopods and tail fan darker,
uropods often with a purple edge. Usually no dark lateral spot at junction of third and fourth abdominal segments.
Juveniles are frequently light greyish with minute brown or olive green specks over entire body and, in
addition, orange ones on abdomen; uropods with brown specks, particularly dense at their distal portions.

Size: Maximum length: females, 236 mm; males, 195 mm.

Habitat, biology, and fisheries: Estuarine and oceanic littoral. Found from the coastline to depths of about
110m(occasionally in deeperwater, to 165 m), mainly onmud or sandymud, sometimes mixed with shell fragments;
the juveniles inhabit muddy or peaty bottoms with shell fragments in estuarine waters. The adults are
mostly active at night, burying in the substrate in daytime. Greatest quantities along the Texas coast and in the
southwestern Bay of Campeche; most important species of Farfantepenaeus off North Carolina. The total
catch for this species exceeds that of other peneids taken in the USA. In the fisheries statistics for the years
1984 to 1998 Farfantepenaeus aztecus has been referred to as Penaeus aztecus. From 1984 to 1998 the capture
production reported from the USA totaled 928 222 t (mean capture production: 61 881 t/year).From 1984
to 1991 the capture production was always greater than 60 000 t, peaking to 78 667 t in 1990. From 1992 on,
the mark of 60 000 t was never attained again. There are no separate statistics for this species in the other
countries of Area 31, where the Farfantepenaeus species are referred together as Penaeus spp. This species
is caught mainly with American-type shrimp trawls (balloon and flat); usually, 2 trawls are towed simultaneously
(double-rig). In inshore and near shore waters it is mainly taken with shrimp trawls (including trynets) and various other types of gear (frame trawls, channel nets, seines, cast nets, push nets, lift nets and set gear). Marketed mostly frozen and fresh; a small fraction of the catch is canned; juvenile and subadult shrimp are mainly sold as bait. This species has been farm-raised on a small scale.
 

Distribution: Martha’s Vineyard, Massachusetts, around peninsular Florida to Sanibel grounds, Appalachicola Bay, around Gulf of Mexico to northwestern Yucatán. F. aztecus extends farther north than any of the other western Atlantic species of the genus.