The oilfish,
The first report from the Mediterranean comes from 1887 by Kolombatović (Bettoso & Dulčić 1999). Rarely found on the Mediterranean coast of Turkey,
The Sea of Marmara is an inland sea, located entirely within the borders of Turkey that connects the Black Sea with the Aegean Sea: the Bosphorus Strait connects it with the Black Sea and the Dardanelles (Çanakkale) Strait with the Aegean Sea. The latter is 62 km long but only 1.3 to 7 km wide, on average 55 m deep, with a maximum depth of 103 m. Water flows in both directions along the strait, from the Sea of Marmara to the Aegean Sea via a surface current and in the opposite direction via an undercurrent (Beşiktepe 2003). The Dardanelles strait waters are economically very important to Turkey, because the region supports the main commercial surroundings and purse seine fisheries.
One specimen of
Morphometric measurements and meristic counts are presented in Table 1. Oilfish was 139 cm long (TL) and weighed 12.4 kg. Body elongated, semi-fusiform, laterally compressed. The mouth large, the lower jaw extends slightly anteriorly to the upper jaw. Strong vomer teeth present in both jaws, fang-like in the anterior part of the upper jaw. The maxilla exceeds the vertical level from the posterior border of the eyes. Two detached dorsal and anal finlets. The anal fin similar to the second dorsal fin in shape and size. Body covered with small cycloid scales interspersed with rows of rough spiny tubercles and dark-brown (Kaya & Bilecenoğlu 1999).
Morphological and meristic data for the specimen of
Morphometric data
Value (cm)
Total length
139
Fork length
127.5
Standard length
120
Anal length
80
Predorsal length
35
Head length
23
Maxillary length
14.5
Snout length
10
Eye diameter
6
Preorbital space
12.5
Dorsal fin base length
72
Anal fin base length
25
Pelvic fin length
11
Caudal fin length
12.5
Anal height
17
Body height
23
Dorsal fin rays
XIII + 16
Pelvic fin rays
I + 5
Pectoral fin rays
15
Anal fin rays
17
Total weight (g)
12 400
Catch depth and fishing gears of
Fishing Gear
Depth (m)
Region
References
Tuna longline
200-400
In the south-central Pacific
Nakamura & Parin (1993)
Longline
-
Mediterranean, Strait of Gibraltar
Buencuerpo et al. (1998)
Shoreline
-
Northern Adriatic Sea
Bettoso & Dulčić (1999)
Longline
180
Mediterranean, Antalya Bay
Kaya & Bilecenoglu (1999)
Commercial bottom trawl
65
Southern Mediterranean
Elbaraasi et al. (2007)
Tuna longline handline
50-250
Brazilian coast
Viana et al. (2012)
Gillnet
100-150
South-eastern coast of India
Sureshkumar et al. (2013)
Bottom trawl
160
Mediterranean, Iskenderun Bay
Gurlek et al. (2013)
Longline
2
North Aegean Sea
Kampouris et al. (2013)
By hand
Shore
Marmara Sea
This study
In the last two decades, the advance of thermophilic species has been the first and most cited evidence for the linkage between climate change and distribution patterns of the biodiversity in the Mediterranean Sea. More than 30 Mediterranean warm-water indigenous fish species have now been recorded north of their original geographical distribution. In poikilothermic organisms such as fishes, the temperature may determine the population and community structure through its direct influence on the survival, reproduction and resource-use patterns of single individuals. Climate warming is driving species ranges toward the poles and this ‘harbinger’ is now perceptible in the Mediterranean realm where a variety of thermophilic organisms, belonging to macroalgae, plankton, invertebrates and, as we expect, fishes, extend their distribution toward northern areas (CIESM, 2008). The northward advance of thermophilic fishes is one of the first, and maybe most detectable biotic response to climatic changes (Azzurro 2008).