Mediterranean horse mackerel: Difference between revisions

{{Short description|Species of fish}}

| status_ref = <ref name="iucn status 19 November 2021">{{cite iucn |author=Smith-Vaniz, W.F. |date=2015 |title=''Trachurus mediterraneus'' |volume=2015 |page=e.T198645A43156470 |doi=10.2305/IUCN.UK.2015-4.RLTS.T198645A43156470.en |access-date=19 November 2021}}</ref>

| subdivision = ''T. m. mediterraneus'' <small>(Steindachner, 1868)</small><br/>

''T. m. ponticus'' <small>Aleev, 1956</small>

The '''Mediterranean horse mackerel''' ('''''Trachurus mediterraneus'''''), also known as the '''Black Sea horse mackerel''', '''horse mackerel''', '''Mediterranean scad''', '''common scad''', or simply '''scad''', is a species of [[mackerel]] in the family [[Carangidae]] found in the eastern [[Atlantic]] from [[Bay of Biscay]] to [[Mauritania]], including the [[Mediterranean Sea]]. It is a [[benthopelagic]], [[subtropical]], marine [[fish]] that can reach up to {{convert|60|cm|in|abbr=on}} in length. In the countries near the Mediterranean and Black Seas, it makes up a significant portion of fish catch, 54% of fish caught in the latter. Despite [[overfishing]] in the 1980s, catch numbers have leveled out and it is listed as [[least concern]] by the [[International Union for Conservation of Nature]].

The Mediterranean horse mackerel was first [[scientific description|described]] in 1868 by [[Austria]]n [[ichthyologist]], [[zoologist]], and [[herpetologist]] Franz Steindachner, who gave it the name ''Caranx trachurus mediterraneus''. It was also described two other times, by Y. G. Aleev in 1956 and J. Dardignac and A. Vincent. Its [[genus|generic]] name comes from the [[Greek language|Greek]] roots ''trachys'' meaning "rough" and ''oura'' meaning "tail".<ref name=fishbase/>

The Mediterranean horse mackerel has an elongated, compressed body (up to {{convert|60|cm|in|abbr=on}} in length, common length {{convert|30|cm|in|abbr=on}}) with a large head and projected lower jaw. The nostrils are small and close-set and the eyes are protected by a well-developed adipose eyelid. Its upper jaw, or maxilla, is also large and wide. Its body is a dusky color, blue to grey to black in color [[dorsum (anatomy)|dorsally]] and on top of the head, while the lower two-thirds of the body is white to silver in color. Its [[caudal fin]] is yellow and it has a distinct black mark just [[posterior (anatomy)|posterior]] to the [[operculum (fish)|operculum]]. It has 36-41 gillrakers and the [[anal fin]] is preceded by two separate spines.<ref name=fao/>

[[File:Black Sea map.png|thumb|left|Map of the Black Sea region]]

The Mediterranean horse mackerel is found in [[subtropical]] waters throughout the eastern Atlantic Ocean from the Bay of Biscay to Mauritania, as well as the Mediterranean Sea, the Aegean archipelago, the Black Sea, the Propontis or [[Sea of Marmara]], and the southwestern Sea of Azov. Its [[latitude|latitudinal]] range extends from [[49th parallel north|49°N]] to [[28th parallel north|28°N]] and its [[longitude|longitudinal]] range extends from [[13th meridian west|13°W]] to [[43rd meridian east|43°E]].<ref name=fishbase>{{FishBase |genus=Trachurus |species=mediterraneus |year=2017 |month=February}}</ref> The subspecies ''T. m. mediterraneus'' is found in the Mediterranean Sea,<ref name=dobrovolov/> while the ''T. m. ponticus'' subspecies, also called the Black Sea scad, is native to the Black Sea, the Sea of Marmara, and the Sea of Azov.<ref name=fishbase/> ''T. m. ponticus'' is found in the territorial waters of every country bordering the Black Sea: Bulgaria, Georgia, Romania, Russia, Turkey, and Ukraine.<ref name=yankova>{{cite journal |last=Yankova |first=M. |author2=D. Pavlov |author3=P. Ivanova |author4=E. Karpova |author5=A. Boltachev |author6=B. Öztürk |author7=L. Bat |author8=M. Oral |author9=M. Mgeladze |title=Marine fishes in the Black Sea: recent conservation status |journal=Mediterranean Marine Science |volume=15 |issue=2 |year=2014 |pages=366–379 |doi=10.12681/mms.700 |url=http://www.medit-mar-sc.net/index.php/marine/article/viewFile/700/541 |format=pdf|doi-access=free }}</ref> Subspecies populations are not isolated and some limited migration between seas occurs. Hybrid offspring have been found in the wild.<ref name=dobrovolov>{{cite journal |last=Dobrovolov |first=I. S. |title=Genetic divergence between the scad of subspecies ''Trachurus Mediterraneus'' (''Carangidae, Pisces'') from the Black Sea and the Mediterranean |journal=Mediterranean Marine Science |volume=1 |issue=1 |year=2000 |pages=133–139 |url=http://www.medit-mar-sc.net/index.php/marine/article/view/284 |format=pdf |doi=10.12681/mms.284|doi-access=free }}</ref><ref name=turan>{{cite journal |last=Turan |first=Cemal |title=Stock identification of Mediterranean horse mackerel (''Trachurus mediterraneus'') using morphometric and meritic characters |journal=ICES Journal of Marine Science |volume=61 |issue=5 |pages=774–781 |year=2004 |doi=10.1016/j.icesjms.2004.05.001 |doi-access=free }}</ref> Its typical depth range is {{convert|5|-|250|m|ft|abbr=on}}, though it can be found as deep as {{convert|500|m|ft|abbr=on}}. It lives near the ocean floor, though it sometimes schools near the surface.<ref name=fishbase/>

A marine species that prefers [[brackish]] water and [[subtropical]] temperatures, the Mediterranean horse mackerel is oceandromous, that is it [[Fish migration|migrate]]s within its native bodies of water. It feeds primarily on [[sardine]]s, [[anchovy|anchovies]], and small [[crustacean]]s.<ref name=fishbase/> It [[Shoaling and schooling|shoals]] with other members of its genus, such as ''[[Trachurus trachurus|T. trachurus]]'' and ''[[Trachurus picturatus|T. picturatus]]''.<ref name=fao/>

Like other mackerels, the Mediterranean horse mackerel's reproduction is [[oviparous]]. Its reproductive cycle is divided into three distinct stages, the prereproductive, reproductive, and postreproductive. The prereproductive stages occurs from January to April and the postreproductive stage occurs from September to December. During these periods, the gonads are much smaller than the reproductive stage. Mating occurs in the summer from May to August, during which testes and ovaries grow significantly in size. The ovaries become a dark orange color and eggs are visible on the surface.<ref name=viette/> Embryonic development occurs in 24–26 hours.<ref name=pora>{{cite journal |last=Pora |first=E. |title=Le chinchard de la Mer Noire (Trachurus mediterraneus ponticus), étude monographique |journal=Institut Roumain de Recherches Marines |pages=753 |year=1979}}</ref> Eggs are pelagic<ref name=fishbase/> and {{convert|0.71|-|0.92|mm|in|abbr=on}} in length.<ref name=sahin/> Sexual maturity is reached at 2 years of age and around {{convert|16|cm|in|abbr=on}} in length for both males and females.<ref name=viette>{{cite journal |last=Viette |first=Michèle |author2=Piero Giulio Giulianini |author3=Enrico Antonio Ferrero |title=Reproductive biology of scad, ''Trachurus mediterraneus'' (Teolostei, Carangidae), from the Gulf of Trieste |journal=ICES Journal of Marine Science |volume=54 |issue=2 |year=1997 |pages=267–272 |doi=10.1006/jmsc.1996.0185 |doi-access=free }}</ref>

It is parasitized by the [[monogenea]]ns ''[[Gastrocotyle trachuri]]'', ''[[Pseudaxine trachuri]]'', and ''[[Cemocotyle trachuri]]''.<ref name="MollaretJamieson2000">{{cite journal|last1=Mollaret|first1=Isabelle|last2=Jamieson|first2=Barrie G.M.|last3=Justine|first3=Jean-Lou|title=Phylogeny of the Monopisthocotylea and Polyopisthocotylea (Platyhelminthes) inferred from 28S rDNA sequences|journal=International Journal for Parasitology|volume=30|issue=2|year=2000|pages=171–185|doi=10.1016/S0020-7519(99)00197-6|pmid=10704600}}</ref>

The Mediterranean horse mackerel is an important resource in the Mediterranean Sea and the Black Sea region.<ref name=turan/> It makes up 54% of catches in the Black Sea and 39% in the Sea of Marmara. In the Aegean and Mediterranean Seas, it only totals 3-4% of annual catches. Fixed nets and [[seine fishing|seine]]s are common methods used to catch Mediterranean horse mackerel.<ref name="iucn status 19 November 2021" /> Along with ''T. trachurus'', it is one of two ''Trachurus'' species in the Mediterranean. Because it forms dense schools and lives in shallower waters, the Mediterranean horse mackerel is the more commonly caught species.<ref name=artüz>{{cite journal |last=Artüz |first=M. Levent |title=The egg and larval growth stages of Horse mackerel Trachurus trachurus (Linnaeus, 1758) from the Sea of Marmara |journal=Fisheries Advisory Commission Technical Paper |issue=202 |year=2000 |url=https://www.researchgate.net/publication/237827974 |format=pdf}}</ref> Along with ''[[Engraulis encrasicolus]]'', it makes up 59% of seafood production in [[Turkey]].<ref name=sahin>{{cite journal |last=Sahin |first=Cemalettin |author2=Necati Hacimurtazaoglu |title=Abundance and distribution of eggs and larvae of anchony (''Engraulis encrasicouls'', Linnaeus, 1758) and horse mackerel (''Trachurus mediterraneus'', Steindachner, 1868) on the coasts of the eastern Black Sea |journal=Turkish Journal of Zoology |volume=37 |issue=37 |pages=773–781 |doi=10.3906/zoo-1212-31 |url=http://dergipark.gov.tr/download/article-file/134371 |format=pdf|year=2013 |doi-access=free }}</ref>

Despite being regularly caught in mixed-species fisheries, the Mediterranean horse mackerel is listed as least concern by the IUCN. Its wide range buffers it from steep population declines, and none has been observed in recent years, with catches leveling out in the past decade. Overfishing in the 1980s led to a steep decline in catches in the Black and Marmara Seas, but has since become stable. Some conservation measures are in place in certain European countries. Minimum catch lengths are {{convert|15|cm|in|abbr=on}} in the [[European Union|EU]], {{convert|10|cm|in|abbr=on}} in [[Ukraine]], {{convert|12|cm|in|abbr=on}} in [[Romania]] and [[Bulgaria]], and {{convert|13|cm|in|abbr=on}} in [[Turkey]].<ref name="iucn status 19 November 2021" />

[[Category:Marine fish of North Africa]]

[[Category:Taxa named by Franz Steindachner]]