The common silver-biddy (''Gerres oyena''), also known as the blacktip silver biddy, Darnley Island silverbelly, longtail silverbiddy, oceanic silver biddy, shining silver-belly or slender silver belly,
is a
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of
mojarra
The mojarras are a family, Gerreidae, of fish in the order Perciformes. The family includes about 53 species found worldwide in tropical and warm temperate regions. They mostly inhabit coastal salt and brackish waters, although some occur in fre ...
native to marine and brackish waters of coastal waters of the
Indian Ocean
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by th ...
and the western
Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...
. It inhabits
estuaries
An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...
, coastal waters and
lagoons
A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'') an ...
. This species can reach a length of , though most do not exceed . This species is important to local
commercial fisheries
Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often ...
.
[
]
Reproduction
Based on the seasonal reproductive cycle of the species, ovary
The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. ...
development of the females occurs from March to September, while the testes
A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testoster ...
development of the males occurs between March and August. For both sexes, the maximal development occurs during April and May. Using the gonadosomatic index
In biology, the gonadosomatic index (GSI) is the calculation of the gonad mass as a proportion of the total body mass. It is represented by the formula:
GSI = onad weight / total tissue weight× 100
It is a tool for measuring the sexual maturity ...
, the minimum standard length (SL) at sexual maturity
Sexual maturity is the capability of an organism to reproduce. In humans it might be considered synonymous with adulthood, but here puberty is the name for the process of biological sexual maturation, while adulthood is based on cultural definitio ...
was 89.7 mm for the females and 81.4 mm for males. The size at which 50% of individuals were sexually mature was 104 mm SL in females and 92 mm SL in males.[Kanak, Khaled and Katsunori Tachihara]
Reproductive biology of common silver biddy Gerres oyena in Okinawa Island of southern Japan
Journal Fisheries Science, Springer Japan Issue, Volume 74, Number 2 , pages 265-275, March, 2008
See also
* Japanese silver-biddy
References
External links
Photograph
*
{{Taxonbar, from=Q1042461
Common silver-biddy
Fish of Japan
Fish described in 1775