Weakfish
(also known as Saltwater trout, Shecutts, Silver squeteague, Gray squwteague, Squit, Chickwick, Bastard trout, and Sandtrout in the USA;  Corvinata real in Spain and Portugal; Pescada-amarela in Brazil; and Wittiewittie in Suriname)

 

Cynoscion  regalis  (Bloch & Schneider, 1801)
(previously classified as Cestreus carolinensis (Gronow, 1854), Johnius regalis (Bloch & Schneider, 1801), Labrus squeteague (Mitchill, 1815), Otolithus obliquatus (Cuvier & Valenciennes, 1879), and Roccus comes (Mitchill, 1814))


 

Weakfish are a member of the Sciaenidae family. Known as drums or croakers, sciaenids use special muscles attached to the wall of the swim bladder (a gas filled organ used primarily for buoyancy control and important for hearing in some fishes). To produce their distinctive sounds,  which are thought to be associated with courtship and spawning behavior, sciaenids rapidly flex these sonic muscles against the swim bladder. Sciaenids are primarily bottom associated, carnivorous fishes distributed worldwide in tropical and temperate inshore waters (see map below). The majority inhabit open sand and mud bottoms and some are found only in brackish waters. Though the exact number of species is unknown, there are probably up to 200 species. Along the western Atlantic there are 56 species in 21 genera. Thirteen species in nine genera are present in the Chesapeake Bay region. Of these, CQFE studies six species as part of its stock assessment for the Virginia Marine Resource Commission (see reports at left).


 

Areas where weakfish have been found


Map from AquaMaps


 

Weakfish are a popular target of sport and commercial fisheries up and down the U.S. East Coast. Although Chesapeake Bay is home to an important population of weakfish, other places have laid claim to this fish. For example, it is the state fish of Delaware as of July 7, 1981, and Fortescue, on the Delaware Bay in New Jersey, calls itself the "Weakfish Capital of the World". The scientific name, Cynoscion regalis, distinguishes the east coast weakfish from other fish bearing this common name. A relative in the Southern Hemisphere, Cynoscion acoupa, is also called "weakfish" but grows much larger, with a 43 inch, 29 pound plus record in Brazil.

Scientists who study fish (ichthyologists) have placed weakfish in the family Sciaenidae, which includes the drums and sea trouts. The sciaenids have well-developed swimbladders that are used in sound production and give the family its common names: drums and croakers. Croakers often make a grunting sound when they are hooked and taken from the water. Moreover, we have located spawning groups of black drum by putting our ears to the bottom of an aluminum boat and listening for the characteristic "boom, boom, boom". The sea trouts differ from the drums in their body dimensions. Sea trout, such as weakfish, are narrower and more streamlined than are the drums.

The sciaenids are primarily bottom associated, carnivorous fishes distributed worldwide in tropical and temperate inshore waters. The majority occur on open sand and mud bottoms and some are found only in brackish waters. The exact number of species is uncertain, but there are probably between 150 and 200. Chao (1976) revised the sciaenids of the western Atlantic and found that they comprise 56 species in 21 genera. Thirteen species in nine genera are known to occur in the Chesapeake Bay region.

Another distinguishing feature of the sciaenids of Chesapeake Bay is their distinctive life-history. Sciaenids reach sexual maturity very early in their lives, typically at just 10% of their potential life span. When the sciaenids reach sexual maturity, they have prodigious reproduction. Reproduction can occur over many months, as often as every other day at times, with each female producing a million or more eggs each time. Weakfish share these family characteristics. Weakfish can live 17 years (the oldest we’ve seen so far) or longer, but most fish become sexually mature at one year of age, and all are sexually mature by two. This corresponds to a size of 6 ½ inches. Thus, weakfish could spawn over as many as 17 years if they reached old age. In Chesapeake Bay the mean age we see now is 4 years and these fish have spawned, on average, 3-4 times. This early age for first reproduction is remarkable, especially when we compare weakfish with other economically-important fish, such as a cod which spawns first when it reaches 30% of its potential life span. This may be one of the reasons that weakfish populations have withstood heavy fishing pressure without collapsing.

Weakfish’s ability to withstand heavy fishing not only results from the number of years it can reproduce, but also because of its great fertility. Weakfish begin spawning shortly after they enter Chesapeake Bay in May and finally finish at the end of August or early September, a period of four months. In the early 1990s, Dr. Susan Lowere-Barbieri found that weakfish spawn a batch of eggs as often as every 2-3 days or as infrequently as every two weeks or so, depending on the environment. Each batch of eggs can number from 100,000 to one-half million. The number of eggs in a batch is related to female size: bigger, older females carry more eggs than smaller females. Thus the reproductive output of a large female could be 4 to 20 million eggs each year. This high reproductive output helps weakfish populations persist even though they have been fished heavily. It also explains why they can recover quickly when fishing pressure is eased.

Weakfish do not grow as quickly to its potential lifetime size as do the drums and croakers. Drums typically reach most of their adult size in the first few years of life. Weakfish grow more slowly and they take five years (30% of their life span) to reach half their potential lifetime length; 10 years (>60%) to reach ¾ of this length, whereas the drums reach ¾ of their lifetime length at only 10% of the life-span. These are the statistics when we use Lowere-Barbieri’s data. When we use the data collected by VMRC and ODU, weakfish reach ¾ of the lifetime length by age 5 out of 9 years (55% of their maximum age in the Bay). This slow growth makes weakfish more vulnerable to growth overfishing than the drums.

In Virginia, most of the weakfish that are harvested are taken in the commercial fishery, although recreational harvest can be substantial. Recently, Virginia and the other East Coast states have been under harvest restrictions in order to reduce overfishing. In Virginia there are both size (recreational and commercial) and season (commercial) limits. See the Virginia Marine Resources Commission website for more details.

In our sampling of Chesapeake Bay, the average age of weakfish is 4 years and we collected fish as young as Young-of-the year (less than 1 year old) and as old as 9 years. The average length was 17 ½ inches, with a range of length from 7 ½ inches to almost 32 inches. The average weight of the weakfish that we sampled is a little under 2 ½ lbs, with a minimum of 3 ounces and a maximum of just over 11 pounds.


 

Weakfish development

At 3.0 mm TL, body depth has increased; ventral series of melanophores more pronounced.

 

At 4.6 mm TL, caudal rays present and dorsal and anal fin rays are slightly differentiated; most melanophores have disappeared except for pigment spots at the base of the anal and on gut (not found in C. nebulosus and C. nothus).

 

At 8.2 mm TL, anal fin rays and soft dorsal rays are present.

 

At 10.5 mm TL, nearly the full complement of dorsal fin elements is present; some lateral pigment; the young assume demersal existence.

 

At 17 mm TL, there are four vertical bands or saddles of chromatophores; anal pigment spot is gone. Body depth increases in proportion to length from hatching until about 17 mm TL, then body becomes more slender

Information from FishBase


 

Images of a weakfish as it develops



All images from Johnson, G. D., 1978, Development of fishes of the Mid-Atlantic Bight. An atlas of egg, larval and juvenile stages. Vol. IV. Carangidae through Ephippidae
Fish and Wildlife Service, U.S. Department of the Interior


 

Age your weakfish

Although weakfish grow more slowly than do the drums, their growth is just as variable. A 20 inch weakfish can be anywhere from 3 to 9 years of age and a 4 lb weakfish can be from 4 to 9 years old. Size and weight alone do not indicate the age of these fish. If you catch a fish that is four years old, how long can it be and how much will it weigh? See if you can tell from the graphs.

Age by Length

 

Age by Weight


 

Listen to weakfish sound 1

Weakfish sounds from the
Discovery of Sound in the Sea website of the
Office of Marine Programs at the University of Rhode Island

Listen to weakfish sound 2

Spotted seatrout sounds from the
Fish Sound Archive of the Sciaenid Acoustics Research Team
(SART)
at East Carolina University

Listen to weakfish sound 3

Spotted seatrout sounds from the
Fish Sound Archive of the Sciaenid Acoustics Research Team
(SART)
at East Carolina University