Uncommon pelagic and deep-sea cephalopods in the Mediterranean: new data and literature review

Abstract

Compared with their shelf-living relatives, the biology and ecology of most pelagic and deep-sea cephalopods are presently relatively little known because of the difficulty in catching them. To compensate for the lack of information regarding these cephalopods, scientists have had to make use of the limited and fragmentary data gathered from different sources, such as sporadic captures, strandings or stomach contents of their predators. In this study, we provide some biological and ecological information on eleven uncommon pelagic and deep-sea cephalopods collected over more than fifteen years of fishery surveys in the western Mediterranean Sea. The cephalopods investigated include two epipelagic octopuses (Ocythoe tuberculata and Tremoctopus violaceus), one deep-sea cirrate octopus (Opisthoteuthis calypso), the sepiolid Stoloteuthis leucoptera and seven teuthoid species inhabiting, preferentially, the mesopelagic and bathypelagic waters (Abraliopsis morisii, Ancistrocheirus lesueurii, Brachioteuthis riisei, Chiroteuthis veranyi, Chtenopteryx sicula, Onychoteuthis banksii and Taonius pavo). Although all of these species are either cosmopolitan or present a wide distribution in other oceans, they are nevertheless relatively rare in catches, and therefore, remain lesser known. The finding of T. pavo represents the first record of this cephalopod in the Mediterranean waters.

Effects of contrasting oceanographic conditions on the spatiotemporal distribution of Mediterranean cephalopod paralarvae

“…This number only accounts for about 19% of the 52 species currently reported in the Balearic Sea (Quetglas, 2003). Furthermore, the species composition of the paralarvae from our sampling contrasts with that of adults, since most paralarvae belonged to species rarely caught as adult in the study area such as Ancistrocheirus lesueurii, Brachioteuthis riisei, Cranchia scabra, Abraliopsis morisii, or Stoloteuthis leucoptera (Quetglas et al, 2013a). However, it is also true that the occurrence of these species was sporadic and only collected once or twice.…”

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“…Kovačić, Đuras Go merčić, Go merčić, Lucić, and Go merčić (2010) didn't find remains of the species in the stomach contents of the Cuvier's beaked whales in the Adriatic Sea, although Ziphius cavirostris is feeding almost exclusively on pelagic squids (Santos et al, 2001). A. lichtensteinii and some other deep-sea pelagic species could be much more abundant in the water co lu mn than previously assumed and therefore also potentially interesting for fisheries (Bello, 1991;Quetglas et al, 2013). Future studies should be focused on assessment of the abundance and also on clarification of behavioural and distributional patterns of A. lichtensteini in the South Adriatic Sea which, based on the present knowledge, represents one of the most important macropelagic species in the food web energy transfer of the mesopelagic and bathypelagic habitat, both as a prey and as a predator.…”

“…First records on A. lichtensteinii are related to the investigations of teutofauna in the western and central basin of the Mediterranean (Naef, 1921;Denger, 1926;Mangold, 1973). Since then, the species has been registered in several areas (Villanueva, 1992;Rasero, Gon zalez, & Guerra, 1993;Lefkaditou, Politou, & Papaconstantinou, 2000;Lefkaditou, Mytilineou, Maiorano, & D'Onghia, 2003;Gon zalez & Sanchez, 2002;D'Onghia et al, 2011;Quetglas et al, 2013), including the Adriatic Sea where its presence was mainly presumed based on findings of beaks in the stomachs of the predators Xiphias gladius and Grampus griseus (Gamu lin-Brida & Ilijanić, 1972;Bello, 1990;Bello, 1991;Bello, 1996). The records outside the Mediterranean are very rare: the Gulf of Mexico (Voss, 1956), off West Africa (Adam, 1962), and the southwestern Pacific (Rancurel, 1970).…”

The Mediterranean Sepiolidae (Mollusca Cephalopoda) diversity

“…Stoloteuthis leucoptera is the only extra-Mediterranean sepiolid that entered this basin in comparatively recent times. It is an amphi-Atlantic species (Reid & Jereb, 2005) that was first recorded in the ligurian Sea thanks to three specimens collected there in 1988 (Orsi Relini & Massi, 1991) and afterwards was found in other western Mediterranean districts (Volpi et al, 1995;Wurtz et al, 1995;Sánchez et al, 1998;Cuccu et al, 2010;Quetglas et al, 2013). The report by Quetglas et al (2013), who netted 25 specimens mostly in the Alboran Sea, is particularly interesting because they started to capture this sepiolid only in 2001, while no one had been caught in previous surveys, from 1994 to 2010.…”

“…It is an amphi-Atlantic species (Reid & Jereb, 2005) that was first recorded in the ligurian Sea thanks to three specimens collected there in 1988 (Orsi Relini & Massi, 1991) and afterwards was found in other western Mediterranean districts (Volpi et al, 1995;Wurtz et al, 1995;Sánchez et al, 1998;Cuccu et al, 2010;Quetglas et al, 2013). The report by Quetglas et al (2013), who netted 25 specimens mostly in the Alboran Sea, is particularly interesting because they started to capture this sepiolid only in 2001, while no one had been caught in previous surveys, from 1994 to 2010. In my opinion, the many Mediterranean occurrences of this cephalopod from the late '80s on, coupled with the lack of previous records from areas well surveyed in the past, soundly support the hypothesis that Sepiola leucoptera naturally entered the Mediterranean Sea from the Atlantic Ocean through the Straits of Gibraltar, extended its range within the western basin and succeeded in generating a self-sustained population (Battaglia et al, 2011).…”