Salmo marmoratus

Salmo marmoratus
Conservation status
Least Concern (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Salmoniformes
Family:	Salmonidae
Genus:	Salmo
Species:	S. marmoratus
Binomial name
Salmo marmoratus Cuvier, 1829

Marble trout (aka Salmo marmoratus) is a species of freshwater fish in the Salmonidae family, the second largest European trout species, second in size only to huchen (Hucho hucho). The marble trout is found in rivers of the Adriatic basin in the Neretva river in Bosnia and Herzegovina, Po River in Italy, Zeta river in Montenegro, Soča and Idrijca rivers in Slovenia and possibly in Albania.^{[1] [2]}

Marmorated trouts

Adding to the confusion of salmonid taxonomy, there are other trout with marble pattern beside Salmo marmoratus. One is trout from the river Otra, Norway. A certain percentage of brown trout from that river has marble pattern. In all other aspects, these trout are identical to the non marble brown trout from the same river. This is an example of intrapopulational polymorphism (biology).^[3]

Recent studies also imply that marble trout from Neretva and Montenegro are not closely related to Salmo marmoratus. The pattern probably developed in geographically remote regions independently. In addition, genetic studies revealed that marble trout from Neretva is genetically indistinct from Salmo dentex.^[4]

Appearance, Biology and Ecology

The marble trout has a long, cylindrical body, slightly compressed laterally, with a large head (22-25% of the body length) which is why it is also known as "Glavatica" ("glava" - head) in Bosnia and Herzegovina. The most obvious characteristic of marble trout is of course the marble pattern. The intensity of colour varies considerably upon the surroundings. Some marble trout have red spots that merge with the rest of the pigment, always only along the lateral line.^[5]

Its average size is 30-70 cm. The largest specimen in Slovenia was a 117 cm and 24 kg female (found dead) ^[6], largest living specimen caught was 120 cm and 22.5 kg ^[7]. There are reports of individuals weighing up to 30 kg^[5]. The largest specimens were found in Bosnia and Herzegovina, inhabiting the Neretva river from below town of Konjic downstream to town of Čapljina, mostly in canyon section from town of Jablanica to city of Mostar, and later after construction of Jablanica dam on the Neretva river in Jablaničko Lake^[8]. Trout become sexually mature at the age 3+ (males) and 4+ (females), they spawn during November and December.

Marble trout is piscivorous, feed mainly on smaller fish and benthic invertebrates.

Its natural habitat is rivers with a summer temperature of 15°C. Hybridization with foreign trout stocked for angling. Water extraction and pollution. In Bosnia and Herzegovina main threats are habitat loss (habitat destruction) due to constructed of five large dams on the Neretva river and plans for construction of several new dams on the upper course of the Neretva, water pollution, overfishing (sportfishing, food, including poaching) and hybridisation with introduced species of trout.

All eight remaining genetically pure marble trout populations were found in remote streams of the River Soča basin.^[9] From these populations the Tolmin Angler's Society launched a reintroduction programme.

References

1. ^ "Marble trout (Salmo marmoratus)". Balkan Trout Restoration Group. http://www.balkan-trout.com/studied_taxa_7_marble_trout.htm. Retrieved 2009-03-10. 
2. ^ Crivelli, A.J. (2006). "Salmo marmoratus". 2006 IUCN Red List of Threatened Species. http://www.iucnredlist.org/search/details.php/19859/all. Retrieved 2007-08-05. 
3. ^ Skaala O, Solberg G (1997). Biochemical genetic variability and the taxonomic position of the marmorated trout in River Otra, Norway. 
4. ^ http://balkantrout.blogspot.com/2009/07/another-myth-busted.html
5. ^ ^{a b} Povž M, Jesenšek D, Berrebi P, Crivelli AJ (1996). The marble trout. 
6. ^ Pintar L (1991). "Najtežja soška postrv je končala pod peskom". Ribič 50 (1-2): 16. 
7. ^ http://ribiska-druzina-tolmin.si/forum/viewtopic.php?p=1324&sid=e40b1d014fb87ba739958c7fb19e99df#1324
8. ^ Mateš, Antun (2004). The Enchanted Angler. Zagreb: J&B d.o.o.. ISBN 953-99019-3-6. http://www.trout-angler.com/the_river_neretva. 
9. ^ Fumagalli L, Snoj A, Jesenšek D, Balloux F, Jug T, Duron O, Brossier F, Crivelli AJ, Berrebi P (2002). "Extreme genetic differentiation among the remnant populations of marble trout (Salmo marmoratus) in Slovenia". Mol. Ecol. 11 (12): 2711–2716. doi:10.1046/j.1365-294X.2002.01648.x. PMID 12453253. http://www.balkan-trout.com/prenos/PDF3_Fumagallimarmoratus.pdf.