June 1st, 2012 by Richard Lord
Pierro Le Cheminant fishing on his trawler, Amy Blue, at the northern end of the Big Russel to the north of Sark, Bailiwick of Guernsey lowered his trawl in about 30 metres of water on the afternoon of 30 May 2012. His net accidentally caught the edge of a reef.
He retrieved his net which produced a couple of john dory, Zeus faber, a lobster, a hand grenade, and a sailfin or silver dory, Zenopsis conchifer.
The hand grenade was disposed of quickly but the silver dory was retained and landed in St Peter Port harbour on 31 May.
The silver or sailfin dory and the john dory have a family resemblance but they are quite different in many ways.
Besides the obvious skin colour difference, and the lack of a black mark on the side of the silver dory, the two fish differ in the profile of the slope of the head. In the john dory it is straight or slightly convex with a notch above the eye, whereas the silver dory has a concave profile above the eye.
The silver or sailfin dory, Zenopsis conchifer, has a widespread distribution.
In the western North Atlantic where it is known as the buckler dory, it is found off Virginia and as far north as the Gulf of Maine.
It appears occasionally for sale at Fulton Fish Market in New York City.
It lives off Argentina and Uruguay in the south-west Atlantic, and in the Indian Ocean where it is found along the coast from South Africa to Somalia, and off the south-west coast of India.
In the eastern Atlantic it lives along the African coast as far south as South Africa. It is a deep water fish living along the outer continental shelf over the continental slope.
Dr Jean-Claude Quero and colleagues writing in the ‘Annales de la Société des Sciences Naturelles de la Charente-Maritime‘ states that the silver dory is mesopelagic, a poor swimmer, and lives close to the bottom.
In 1966 two small silver dory of about 17 to 18 cm long where caught off the south-west tip of Portugal. These were the first records of the fish in European waters.
Dr. Jean-Claude Quero, a scientist formerly at IFREMER, in La Rochelle, recorded 34 captures of the silver dory off the Atlantic coast of Europe between 1966 and 1995 in water depths of 100 to 500 metres.
Over about the last 50 years the silver or sailfin dory has been captured at higher and higher northern latitudes.
In 1970 the first silver dory catch was reported off north-west Spain, and in 1975 a specimen was captured in the Bay of Biscay.
In 1980 a capture was made off the west coast of Ireland and another to the north-west of Ireland in 1993.
Declan Quigley wrote a paper on the three dory species (john dory, silver dory and red dory) found in European seas. He wrote there was an influx of the silver or sailfin dory in Irish waters between 1993 and 1995. He also reported a record of a capture of this species off Iceland in 2002.
Not only is this fish moving north but it seems to be growing in abundance in southern latitudes.
Formerly it was rare but Dr Quero reported that Moroccan boats were fishing for it in deeper water.
Pierro Le Chemant’s silver dory was gutted and kept on ice. On 31 May 2012 it had a gutted weight of 953 grams and a total length of 475 mm. The peritoneum of the abdomen was heavily parasitised with worms.
According to a report by Doug Herdson, the first confirmed silver dory was caught in British waters on 29 August 29, 1995.
Another silver dory was trawled six miles west of Wolf Rock, Cornwall on 23 September 2002. This specimen was 38 cm long and had a gutted weight of 550 grams.
The silver or sailfin dory, Zenopsis conchifer, is is one of many fish species that has been reported moving north as a consequence of a warming ocean, and possibly available ecological niches.
This fish joins the almaco jack, the Guinean amberjack, the two-banded bream, and the white bream as recently arrived in Guernsey waters.