Náttúrufræðingurinn - 2007, Side 19

Tímarit Hins íslenska náttúrufræðifélags
SUMMARY
Recent changes in the distribution
of anglerfish in Icelandic waters
Anglerfish (Lophius piscatoríus) is distri-
buted in the eastem Atlantic Ocean from
Gibraltar north to Iceland and North
Norway. During the last decades,
anglerfish in Icelandic waters has been
most abundant in the warm waters in the
south and southwest while it has been
rare north and east of the country. This
study describes recent changes in the
spatial distribution and abundance of
anglerfish in Icelandic waters, based
mostly on data collected from the
Icelandic groundfish survey in March
that has been conducted annually since
1985. The stock size of anglerfish appears
to have been increasing dramatically
since 1998 and the species has been
extending its spatial distribution along
the continental shelf west off Iceland all
the way to the areas northwest and north
of Iceland. North Icelandic waters may,
8. mynd. a) Vísitala eins og tveggja ára skötusels í milljónum fiska og b) heildarvísitala
stofnstærðar skötusels í þúsundum tonna í Stofnmælingu botnfiska árin 1985-2006
(skyggða svæðið sýnir eitt staðalfrávik í mati á vísitölu stofnstærðar). - a) Abundance
indicesfor one and two year old anglerfish (million fishes) and b) index of total biomass
of anglerfish (thousand tonnes) in the Icelandic Groundfish Survey in 1985-2006 (the
shaded area indicates one standard deviation in the biomass estimates).
however, in some years be hazardous for
this species due to harsh winter condi-
tions.
According to the Icelandic groundfish
survey, anglerfish is rarely found in
waters where bottom temperature is
below 5°C. The changes in the distri-
bution of anglerfish and increased stock
size have co-occurred with rising water
temperatures, and the latter are likely to
have expanded suitable grounds for the
species. These environmental changes
may especially have benefited juveniles,
since recruitment was hardly observed
before year-class 1998 but since then
several large year-classes have been
observed.
It is possible that a part of the stock of
anglerfish in Icelandic waters originates
from distant areas, either due to larval
drift or active migration of larger fish.
Migrations from the Shetland and Faroe
Islands to the continental shelf south of
Iceland have recently been confirmed by
tagging experiments but the magnitude
of the migration is not known.
However, it is likely that since 1998 local
recruitment contributes more to the
stock than possible migrations from
other areas.
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