Mola mola 

Scope: Europe
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Actinopterygii Tetraodontiformes Molidae

Scientific Name: Mola mola (Linnaeus, 1758)
Regional Assessments:
Common Name(s):
English Ocean Sunfish, Giant Sunfish, Headfish, Mola Ocean Sunfish, Moonfish, Sunfish, Sun-fish
French Môle, Môle Commun, Poisson-lune, Poisson Lune
Spanish Mola, Peixe Lua, Pez Cabeza, Pez Luna, Pez Sol
Tetraodon mola Linnaeus, 1758
Taxonomic Source(s): Eschmeyer, W.N. and Fricke, R. (eds). 2015. Catalog of Fishes: genera, species, references. Updated 2 September 2015. Available at: http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp. (Accessed: 2 September 2015).
Taxonomic Notes: Recent investigations of M. mola mitochondrial sequences showed evidence that the genus Mola contains two species: M. mola and the southern sunfish, M. ramsayi (Bass et al. 2005). Report from Yoshita et al. (2009) concluded that the genus Mola contained three species.

Assessment Information [top]

Red List Category & Criteria: Data Deficient (Regional assessment) ver 3.1
Year Published: 2015
Date Assessed: 2013-10-11
Assessor(s): Rijnsdorp, A.D. & Papakonstantinou, C.
Reviewer(s): Strongin, K.
Facilitator/Compiler(s): Kemp, J.R.

European Regional Assessment: Data Deficient (DD)

Mola mola is widely distributed throughout European waters from the English channel south to the Canary Islands, including the Mediterranean. it is associated with depths of at least 400 m and is most often found on the slopes adjacent to deep water. Mola mola is a relatively long-lived species and is slow to mature. In the English Channel, Ireland and Portugal, M. mola have undergone drastic reduction in abundance. In Ireland, there has been a decline in catch landings of about 100% (13 to 0 metric tonnes) in 2 years (2000 through 2002). There is also a decline in Portugal from 12 metric tonnes in 1999 to about 0 in 2009. 

In the Mediterranean, Mola mola comprises a significant fraction of the by-catch (upwards of 70+%) of Spanish drift gillnet fisheries, as well as long-lines, mid-water trawls and even harpoons. Currently, there are no specific regulations in place for the Giant Sunfish in the northeastern Atlantic, but Morocco has recently passed a law to phase out driftnet use in the areas where Mola mola are most likely to be taken. The numerical data suggest that there is, indeed, a steep decrease in the Giant Sunfish population in the northeastern Atlatic, but it has yet to be determined how responsible bycatch is for the decrease in population, as well as what stages of maturation the bycatch is and what the mean length of the landed Sunfish is. Therefore, for the European Regional Assessment, Mola mola is assessed as Data Deficient because of the lack of specific bycatch information and how it is affection the population of Giant Sunfish in the region. 

Geographic Range [top]

Range Description:Mola mola is distributed in warm and temperate zones of all oceans, including the eastern Pacific, the western Pacific, the western Atlantic and the eastern Atlantic (Tortonese 1990). In the eastern Atlantic, it is found from Scandinavia to South Africa, as well as the western Baltic Sea, North Sea and Mediterranean Sea, including the Hellenic Seas (Papaconstantinou 1988, C. Papaconstantinou pers. comm. 2013).

It is associated with depths of up to 400 m (Cartamil and Lowe 2004).
Countries occurrence:
Albania; Algeria; Belgium; Croatia; Cyprus; Denmark; Egypt (Egypt (African part), Sinai); Faroe Islands; France (Corsica, France (mainland)); Germany; Gibraltar; Greece (East Aegean Is., Greece (mainland), Kriti); Guernsey; Ireland; Israel; Italy (Italy (mainland), Sardegna, Sicilia); Jersey; Lebanon; Libya; Malta; Monaco; Montenegro; Morocco; Netherlands; Norway; Poland; Portugal (Azores, Madeira, Portugal (mainland)); Slovenia; Spain (Baleares, Canary Is., Spain (mainland), Spanish North African Territories); Sweden; Syrian Arab Republic; Tunisia; Turkey; United Kingdom (Great Britain, Northern Ireland)
FAO Marine Fishing Areas:
Atlantic – eastern central; Atlantic – northeast; Mediterranean and Black Sea
Additional data:
Lower depth limit (metres):400
Range Map:190422-1

Population [top]

Population:Mola mola comprised between 70 and 93% of the total fish catch in Spanish drift gillnet fisheries within the Mediterranean between 1992 and 1994 (Silvani et al. 1999). In Irish and Celtic Seas, a total of 68 Mola mola were spotted from 2003 through 2005, or an overall density of 0.98 sunfish per 100 km2 (Houghton et al. 2006). Over the course of a six year period that consisted of 1,651 hours of observation, 15 individuals were observed in the Western English Channel (Sims and Southall 2002).

In Ireland, there has been a decline in catch landings of about 100% (13 to 0 metric tonnes) in 2 years (2000 through 2002). There is also a decline in Portugal from 12 metric tonnes in 1999 to about 0 in 2009 (FAO 2011).

In Morocco, a recent study suggests an annual by-catch of 36,450 ocean sunfish, however most are returned alive (Tudela et al. 2005).

There are a very small number of discards in the Greek tuna fisheries (Peristeraki et al. 2008 ICCAT paper). Six ARSA surveys showed 49 specimens, with 39 from one survey.
Current Population Trend:Decreasing
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:Habitat and Ecology
Adult Mola mola are found on slopes adjacent to deep water where they come in for shelter and for seeking cleaner fishes. They are usually shy. However, they may become familiar with divers in some locations (Kuiter and Tonozuka 2001). Individuals often drift at the surface while lying on its side but can swim actively and are capable of directional movements otherwise (Pope et al. 2010). 

Mola mola is a relatively long-lived species. The lifespan or reproductive age of M. mola under natural conditions is unknown, although captive animals have been maintained for more than 8 years (Nakatsubo et al. 2007).  Using these measurements Mola mola longevity has been estimated at 22 years (based on the average of 20 and 23 years old). A growth curve derived from repeated measurements of captive specimens estimated an individual with a total length of 3 m would be about 20 years old (Nakatsubo 2008). Recent work used growth band pairs in vertebrae to age the closely related Sharptail Mola, M. lanceolatus, caught in the eastern Taiwan fishery (Liu et al. 2009). The age estimates ranged between >2 and >23 years for females and >1 and >16 years for males (Liu et al. 2009). Females are larger than males, with all animals larger than 250 cm TL being female (Nakatsubo 2008). Known to have parasites (Pope et al. 2010).

Vertical Migrations
Mola mola is an active swimmer, capable of highly directional movements and the horizontal movements were independent of the current (Cartamil and Lowe 2004). They swim upright and close to the surface. Mola mola uses its anal and dorsal fins as a pair of wings (Pope et al. 2010). Ocean sunfish stroke their dorsal and anal fins synchronously to generate a lift-based thrust that was likened to the symmetrical beats of penguins (Watanabe and Sato 2008). Cartamil and Lowe (2004) observed a diel pattern in depth utilization, with fish residing in the warmer mixed layer above or within the thermocline at night and repeatedly diving beneath the thermocline into cooler water during the day. Hays et al. (2009) also noted that although individual sunfish showed a range of preferred depth that altered over time, they were still moving up and down the water column and regularly returning to close to the surface. Although its exact function has yet to be resolved, Cartamil and Lowe (2004) proposed that periodic returns to the surface in M. mola may imply some form of behavioral thermo-regulation i.e. prolonged time in cold waters necessitates time spent at the surface to re-warm. This may explain the frequent observations of ocean sunfish observed swimming on their sides at the surface during the day (Cartamil and Lowe 2004). Conversely, Sims et al. (2009) argued that extensive vertical movements may simply reflect a crepuscular searching strategy when prey are descending or ascending, with sunfish attempting to locate maximum prey abundances at this time. It has been also been suggested, more generally, that large amplitude dives or ascents of large pelagic fish and other vertebrates during prey tracking may represent prey searching behaviour (Shepard et al. 2006) characterized by extensive movements to new locations (Sims et al. 2008).

Ocean sunfish are obligate or primary feeders on gelatinous zooplankton (Fraser-Brunner 1951, MacGinitie and MacGinitie 1968, Hooper et al. 1973, Bass et al. 2005). 

Very few studies have been conducted on the reproductive biology of ocean sunfish (Pope et al. 2010). In Japan, the spawning period of M. mola is estimated between August and October and the same study also identified asynchronous egg development, suggesting they are multiple spawners (Nakatsubo et al.2007). A more atypical captive growth rates have been found to be between 0.02 and 0.49 kg/day in weight (M. Howard and T. Nakatsubo pers. comm. in Pope et al. 2010) and on average 0.1 cm/day TL (Nakatsubo and Hirose 2007). Age at first maturity is unknown, but inferred to be between 5 and 7 years. Generation length = 22-6 = 18/2 = 9 years. 9 years *3 = 27 years 3 generation lengths.

Use and Trade [top]

Use and Trade: Mola mola is not targeted by European fisheries, but is captured in large numbers as by-catch, mainly in tuna fisheries, in fisheries using long lines, drift gillnets, midwater trawls, and harpoons (in Sicily) in a number of widely distributed fisheries, including those of the Mediterranean (Pope et al. 2010).

Threats [top]

Major Threat(s): Ocean sunfish populations may be vulnerable to fishing activity because of the high levels of bycatch observed in many fisheries (Silvani et al. 1999, Cartamil and Lowe 2004, Fulling et al. 2007, Petersen and McDonell 2007).

Conservation Actions [top]

Conservation Actions: There are no known conservation efforts in the northeastern Atlantic and adjacent regional waters for M. mola. The Moroccan government passed a law in 2007 to phase out the use of driftnets wherein Mola mola are often caught as bycatch. Its distribution overlaps with some marine protected areas in parts of its range; however, the efficacy of the MPAs for conservation of pelagic species remains unknown (Game et al. 2009). Research into all aspects of this species' population, biology, harvest levels and potential threats is needed for this species.

This species was assessed as Data Deficient in the 2007 Mediterranean Assessment (Abdul Malak et al. 2011, IUCN 2011).

Citation: Rijnsdorp, A.D. & Papakonstantinou, C. 2015. Mola mola. The IUCN Red List of Threatened Species 2015: e.T190422A45141101. . Downloaded on 21 September 2017.
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