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Sardinella tawilis

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Sardinella tawilis
Sardinella tawilisbeing sold in a market.
Scientific classificationEdit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Clupeiformes
Family: Dorosomatidae
Genus: Sardinella
Species:
S. tawilis
Binomial name
Sardinella tawilis
(Herre,1927)
Synonyms[citation needed]

Sardinella tawilis(thefreshwater sardinella,freshwater herring,bombon sardineorfreshwater sardine) is a freshwatersardinefound exclusively in thePhilippines.It is the only member of the genusSardinellaknown to exist entirely in fresh water.[2]Locally, they are known inFilipinoastawilis.[2]

S. tawilisis listed in theArk of Tasteinternational catalogue of endangeredheritage foodsofPhilippine cuisineby theSlow Foodmovement.[3]

In January 2019, theInternational Union for Conservation of Naturedeclared S. tawilisan endangered species.[4][5][6]

Etymology and taxonomic history[edit]

Sardinellais the diminutive of the Greeksarda,meaning literally "little sardine".

The species was originally identified and named in 1927 asHarengula tawilisbyAlbert William Herre,the Chief of the Fisheries Division of the Bureau of Science in Manila. The species was later moved to the more appropriate and taxonomically accurate genus,Sardinella.[2]

Description[edit]

S. tawilisis a small fish reaching up to 15 cm and weighing less than 30 g. Like other members of their family, they have laterally compressed bodies with bellies covered in tough, scale-likescutes.They have a single, triangular dorsal fin and a forked caudal fin. They possess long, slendergill rakersin their mouths.[2]

Range and distribution[edit]

S. tawilispopulations are only found inTaal Lakein theBatangasprovinceon the island ofLuzonin the Philippines. Taal Lake is the third-largest lake in the Philippines and is located in thecalderaof anancient volcano.[7]It has an area of about 24,356.4 hectares (60,186 acres) and lies at nine municipalities and two cities. Near its center lies the 23.8-square-kilometer (9.2 sq mi) Volcano Island which has a 1.9-kilometer (1.2 mi) crater lake in the middle. The lake has a maximum depth of 180 meters (590 ft) and an average depth of 65 meters (213 ft).[8]Before recent history, the lake was but an extension of the entirely marineBalayan Bay,connected by a channel that narrowed through time and transpired as ariver.[9]Major eruptions in the 18th centuryessentially sealed the lake from the sea, eventually leading its waters to become fresh water.S. tawilisis believed to be one of a few former marine species trapped within the lake that have evolved into purely freshwater species.[2]

Ecology[edit]

S. tawilis,like members of its family, is anepipelagicfilter feeder,using its gill rakers to strain plankton from the water while it swims with its mouth open. They roam the lake in large schools, just below the surface as the volcanic (and thus sedimentary) nature of the lake limits their plankton food to the surface.

The freshwater sardinella prefers to ingest larger prey, such as adultcopepods,supplemented withrotifersandwater fleas.During the summer months when the density of smaller copepods were much higher, their stomach contents consisted primarily ofcalanoidcopepods, which are larger than the copepods blooming during this time. This suggests some partial control over prey selection exhibited by the fish, as opposed to simple filter-feeding.[10]

Little is known about their reproduction.[11]It is known that the Taal population spawns during the months of April to July, when surface temperatures are highest.[10]

The reproduction of the species saw a decline after theeruption of Taal Volcano in 2020.[12]

Importance to humans[edit]

Bins ofS. tawilisfor sale at a Metro Manila supermarket

Despite its threatened status,[13]stocks in Lake Taal have been commercially fished for several decades. The fish is a widely popular food fish in the Philippines, and tons are shipped to most of the major cities in the country. Local supermarkets and wet markets usually have a tray or pile dedicated solely to the species.[citation needed]

The species is commonly referred to astawilisin the local language ofTagalog.On the island ofCebu,one of the many places wheretawilisis shipped, the nativeCebuanoname for the fish istunsoy.[2]

In addition to raw consumption,tawilisis also processed into various food products. It is one of the many fish species dried, salted, and sold asdaingin the country. They are also smoked and bottled in oil, and sold commercially.[citation needed]

In literature,Jose Rizalused three driedtawilisin his novelNoli Me Tangereto symbolize the Three Martyred Priests of Bagumbayan (Jose Burgos,Jacinto ZamoraandMariano Gomez).[citation needed]

Conservation[edit]

Because of several factors, the species is threatened byoverfishing.As with all species consisting of a single population in one location, a local extinction event will lead to species extinction. As the population of the Philippines grows, the demand will be greater fortawilis,possibly overfishing the lake's stock population. According to theIUCN Red Listreport which conducted last 28 February 2017 and published in 2018, the catch of thetawilisstarted to decline since 1998 due to overfishing, illegal use of active fishing gears, increasing use of fish cages, and the deterioration of the water quality in Taal Lake. The harvest of thetawilishas said to declined by at least 50 percent over the past 10 years. Because of this, the IUCN listed thetawilisas endangered.[4][5][6]

In February 2021, sometawiliswere taken out of Taal Lake due to Taal Volcano's increasing volcanic activity. The conservation project led and funded by theDepartment of Science and Technology'sCouncil for Agriculture, Aquatic, and Natural Resources Research and Developmentresettled thetawilisatUniversity of the Philippines Los Baños's Limnological Station.[14]

Sources[edit]

  • "Sardinella tawilis".Integrated Taxonomic Information System.Retrieved7 January2007.
  • Whitehead, Peter J.P. (1985). "FAO species catalogue. Vol. 7. Clupeoid fishes of the world (suborder Clupeioidei). An annotated and illustrated catalogue of the herrings, sardines, pilchards, sprats, shads, anchovies and wolf-herrings. Part 1 – Chirocentridae, Clupeidae and Pristigasteridae".FAO Fisheries Synopsis.125(7/1). Rome, Italy: Food and Agriculture Organization of the United Nations: 1–303.ISBN92-5-102340-9.

References[edit]

  1. ^"Sardinella tawilis".IUCN Red List of Threatened Species.
  2. ^abcdefFroese, Rainer, and Daniel Pauly, eds. (2010).Sardinella tawilisinFishBase.November 2010 version.
  3. ^"Tawilis".Slow Food Foundation for Biodiversity.Retrieved19 December2018.
  4. ^abJazul, Noreen (24 January 2019)."'Tawilis' now an endangered species ".Manila Bulletin.Retrieved24 January2019.
  5. ^ab"Taal Lake's Tawilis now on list of endangered species".CNN Philippines.24 January 2019. Archived fromthe originalon 25 January 2019.Retrieved24 January2019.
  6. ^ab"Isdang tawilis, endangered species na"(in Filipino).ABS-CBN News.23 January 2019.Retrieved24 January2019.
  7. ^"A Homepage for Taal Volcano".www.iml.rwth-aachen.de.Retrieved28 February2021.
  8. ^"The Philippine Journal of Fisheries".www.nfrdi.da.gov.ph.Retrieved26 February2021.
  9. ^https://repository.seafdec.org.ph/bitstream/handle/10862/831/cemplrfa_p133-147.pdf[bare URL PDF]
  10. ^abPapa, Rey Donne S.; Roberto C. Pagulayan; Alicia Ely J. Pagulayan (2008)."Zooplanktivory in the Endemic Freshwater Sardine, Sardinella tawilis (Herre 1927) of Taal Lake, the Philippines"(PDF).Zoological Studies.47(5). Taipei, Taiwan: Academia Sinica: 535–543.Retrieved26 December2008.
  11. ^Castillo, B.B.; A.S. Castillo; C.L. Gonzales (1975). "Tawilis fishery resources investigation of Taal Lake.".Philippine Council for Agriculture and Resources Research Fisheries Forum.Los Baños, Laguna, Philippines: Philippine Council for Agriculture and Resources Research. pp. 75–98.
  12. ^Ocampo, Karl R. (16 January 2020)."'Tawilis' production seen to decline after Taal blast ".Retrieved28 February2021.
  13. ^(2010_11)."Sardinella Tawilis, Philippine Information".FishBase. Retrieved on 10 February 2011.
  14. ^"Some tawilis removed from Taal Lake for conservation".Retrieved28 February2021.

External links[edit]

Retrieved from "https://en.wikipedia.org/w/index.php?title=Sardinella_tawilis&oldid=1203263640"