International Journal of Marine Science 2016, Vol.6, No.41, 1-4
2
part of Masfjorden, a narrow fjord in Western Norway, which is a relatively undisturbed area, with few people
living there and very little boat traffic. The fyke net is a traditional fishing gear for costal cod in Norway, which
consist of a leader connected to a funnel shaped trap. The fyke net was put out on 15
th
November 2013. The fyke
net was collected on 21
st
November 2013. In total, 14 cod were caught. On the day of collection, the fish was
radiographed with a Porta 100 HF (Eickemeyer Medizintechnik für Tierärzte KG, Tuttlingen, Germany) at 40kV
and 10 mAs onto a 35x43cm image plate in a rigid cassette (Dürr Medical, Bietigheim-Bissingen, Germany) from
70cm above. The image plate was subsequently scanned with a CR 35 VET, Dürr Medical and converted into a
digital TIFF file with Vet-Exam plus Software, version 4.14.0. The images were further processed using Adobe
Photoshop, version CS2. During evaluation of the radiographs we detected the cod with the can inside the
stomach. After the radiological examination all 14 fish were put at 40 meters depth inside a pot to study
barotrauma effects in a separate study (Humborstad et al., 2016).
2 Results and Discussion
At the same day as the specimen was caught it was put at 40 meters depth inside a pot with 13 other cod. At this
stage the fish was alive and active. Four days later a video record showed a motionless cod inside the trap. On 2
nd
December 2013, when the pot was brought to the surface, the fish was found dead inside the pot.
The fish had decomposed to a state where dissection was no longer possible. Neither had the radiographs been
analyzed, so we did not know the presence of the can at this stage, and it was for that reason not retrieved. The can
observed inside the stomach of the cod was not a full length can (344 mm), only the top of the can with a diameter
of 67 mm was left, and it looked from the radiograph that the lower part was eroded away or chopped off (Figure 1).
Figure 1 Radiograph of a cod (
Gadus morhua)
with a beverage can in the stomach. Undigested bone (arrowhead) and beverage can
(asterisk).
The presence of undigested bone in the front of the can (Figure 1) may suggest that the can was blocking the
normal passage through the digestive tract. When trapped in fyke nets, cod often eat smaller fish that are also
trapped inside the net (authors own observation). The cod in the present study may have had a reduced feeding
capacity due to the ingestion of the relatively big can; being able to feed on easily caught prey inside the trap, the
cod may have ingested more than it could handle with a blocked digestive tract. In addition to the blockage of the
intestine by the beverage can, there might have been other factors that caused the death of this fish. Damage of the
internal organs or tissues by the piece of litter such as can, the possible infection by germs transferred to the fish
by the can, and the stress condition that the fish was in is all plausible reasons for the death of this fish.
