STARRY FLOUNDER

STARRY FLOUNDER

LIFE HISTORY

Adult Stage:

Adults are demersal and occur mainly from central California northward, in estuaries and at depths < 150 m, over soft bottoms.

Composites: estuarine, non-rocky shelf

Spawning Stage:

Spawning occurs during winter and spring at depths <45 m, over soft bottoms.

Composites: estuarine, non-rocky shelf

Juvenile Stage:

Juveniles are demersal and occur at depths <100 m, over soft bottoms.

Composites: estuarine, non-rocky shelf

Larval Stage:

Larvae are pelagic and occur in waters <70m.

Composites: estuarine, neritic

Egg Stage:

Eggs are pelagic and occur at depths from 20-70 m.

Composites: estuarine, neritic

Range

Starry flounder are found in the western Bering Sea and north of the Bering Strait south to Los Angeles Harbor, California. They are common in Puget Sound [94, 114, 260].

Fishery

Starry flounder are not a commercially important flatfish, except in Puget Sound. Starry flounder are captured by bottom trawl. They aren’t generally targeted recreationally, but they are taken quite often by anglers fishing from boats or steep rocky banks.

Habitat

Starry flounder is an important member of the inner continental shelf and shallow sublittoral communities [260]. Older juveniles and adults are found from 120 km upstream to the outer continental shelf at 375 m, but most adults are found in less than 150 m [260]. Most spawning occurs in estuaries or sheltered inshore bays [270], in less than 45 m of water.

Eggs and larvae are epipelagic; juveniles and adults are demersal [94]. Eggs occur at or near the surface over water 20-70 m deep [63, 94, 114]. Larvae are found in estuaries to 37 km offshore. Juveniles are found in estuaries and the lower reaches of major coastal rivers [114, 270]. Adults also occur in estuaries or their freshwater sources year-round in Puget Sound [94].

Juveniles prefer sandy to muddy substrates, and adults prefer sandy to coarse substrates [260]. Eggs are found in polyhaline to euhaline waters; juveniles are found in mesohaline to fresh water; adults and larvae are found in euhaline to fresh water [63, 94, 270]. All life stages can survive and grow at temperatures below 0EC to 12.5EC [260].

Movements and Migrations

Starry flounder is not considered to be a migratory species. However, adults move inshore in late winter-early spring to spawn and offshore and deeper in the summer and fall, but these coastal movements are generally less than 5 km [63]; [260]. Some starry flounder have shown movements of >200 km [63], but this is not considered typical. Adults and juveniles are known to swim great distances up major coastal rivers (>120 km) but not following any migratory trend. Larvae may be transported by oceanic currents great distances.

Reproduction

Starry flounder are oviparous; eggs are fertilized externally [94]. Spawning occurs annually in a short time frame in winter and spring, with the exact timing depending on location. In California, starry flounder spawn from November-February, peaking in December [94, 270]. In Puget Sound, spawning occurs from February-April, peaking in March [94, 114]. In British Columbia and the Gulf of Alaska, spawning occurs from February-May, peaking in early April [114].

In the Bering Sea, females of 38-48 cm produced between 900,000 and 2,500,000 eggs [260]. In California, a 56-cm fish had 11,000,000 eggs [270].

Growth and Development

Fertilized eggs are spherical and between 0.89 and 1.01 mm in diameter [114, 260]. Embryonic development is indirect and external. Eggs hatch in 2.8 days at 12.5EC, 4.6 days at 10.0EC, and 14.7 days at 2.0-5.4EC [94, 114, 300].

Larvae hatch at 1.93-2.08 mm and float with their yolk sacs up [94, 114, 300]. The yolk sac is gone in 4-5 days, by the time the larvae reaches 6 mm [94]. Metamorphosis to the benthic juvenile form occurs at 10-12 mm [94, 299]. Sexually immature juveniles range in size from 10 mm to 45 cm, depending on sex [63, 114, 197, 270].

Females begin maturing at 24 cm and 3 years, but some may not mature until 45 cm and 4-6 years [94, 114, 197, 270]. Males begin maturing at 2 years and 22 cm, but some may not reach maturity until 4 years and 36 cm [94, 114, 197]. After 2 years, females grow faster than males and reach larger sizes. Maximum age is reported as 21 years [260].

Trophic Interactions

Larvae are planktivorous. Juveniles and adults are carnivorous. At 5-12 mm, larvae eat copepods, eggs and nauplii as well as barnacle larvae and diatoms [114, 300]. Small juveniles feed on copepods, amphipods and annelid worms [231]. Barry, et al., [26] reported that adult starry flounder in Elkhorn Slough, California fed on 87 different taxa of prey over one year, yet mollusks and infaunal worms made up >65% of their diet. Large fish fed on a wider variety of items, including crabs and other more mobile foods. In other areas, clams and benthic fishes are an important part of the starry flounder’s diet [260]. Starry flounder do not feed during spawning or coldwater periods [260].

Larvae are eaten by larger fish and herons. Juveniles and adults are eaten by pinnipeds, larger fishes, sharks and marine mammals [260]. Wading and diving seabirds such as herons and cormorants feed on juvenile starry flounder [115].

Starry flounder probably competes with other soft-bottom benthic fishes of estuaries and shallow nearshore bays. It occasionally interbreeds with the English sole to produce a hybrid [260].

STARRY FLOUNDER

SUMMARY TABLE