Jón Sólmundsson

Marine and Freshwater Research Institute, Iceland · Demersal Division

Temperature fluctuations impact the distribution of various marine fish species and typically result in distributional changes, seeing either a geographical expansion or, possibly, a retraction. Survival and fitness in the new habitat depend, however, on the species’ adaptability capacity. Here, we describe changes in geographical distribution of I...

Gerð er grein fyrir framkvæmd og helstu niðurstöðum stofnmælingar botnfiska á Íslandsmiðum sem fram fór dagana 27. febrúar til 17. mars 2023. Niðurstöður eru bornar saman við fyrri ár en verkefnið hefur verið framkvæmt með sambærilegum hætti ár hvert frá 1985. The report describes the implementation and main results of the Icelandic Groundfish Sur...

Á árunum 2019-2022 voru 18 894 þorskar merkir við Ísland, þar af voru 358 þorskar einnig merktir með rafeindamerkjum. Af þeim er búið að endurheimta 945 þorska, þar af 16 með rafeindamerki. Merkingarnar hafa farið fram á mismunandi svæðum og árstímum. Í þessari skýrslu eru teknar saman helstu niðurstöður merkinganna og þeim skipt upp eftir merkinga...

Í byrjun árs 2022 hófst átaksverkefni í þorskrannsóknum og áætlað er að verkefnið taki fimm ár. Í verkefninu er lögð áhersla á þrjú meginviðfangsefni, öll með það að markmiði að bæta ráðgjöf um veiðar á íslenska þorskstofninum. Þessari skýrslu er ætlað að gefa yfirlit yfir framgang verkefnisins árið 2022 en jafnframt er tekin saman staða þekkingar,...

Fish are sometimes found washed up on Icelandic shores but rarely in such large quantities that it attracts attention. The beginning of the year 2022 was characterized by frequent and heavy storms.1 After one such storm, large numbers of Norway redfish (Sebastes viviparus), along with other species, were found beached in Stóra Sandvík and on other...

Natural mortality (M) is difficult to measure directly in exploited fish stocks. Therefore, in stock assessments, M has usually been assumed to be constant for age classes of fishable size. However, M is likely to vary annually due to temporal changes in food availability, predation, fish size at age, and other biological and environmental factors....

The report describes the implementation and main results of the Icelandic Groundfish Survey, carried out during 28 February to 24 March 2022. This standardized survey has been conducted annually since 1985 and the present results are compared with those of previous years.

Handbók þessi lýsir framkvæmd rannsóknaverkefnisins „Stofnmæling botnfiska á Íslandsmiðum“ (SMB) sem fer fram í marsmánuði á hverju ári. Í handbókinni er nákvæmlega lýst fyrirhugaðri framkvæmd verkefnisins í mars 2022, m.a. umfangi gagnasöfnunar, hvernig safna eigi líffræðilegum upplýsingum, skráningu mælinga, veiðarfæri og veiðiaðferðum. Einnig er...

ÁRIÐ 2017 veiddist brislingur (Sprattus sprattus) í fyrsta sinn á Íslandsmiðum svo vitað sé. Á næstu árum fjölgaði brislingum sem veiddust við landið og í rannsóknarleiðangri í mars 2021 fengust alls 375 brislingar, einkum fyrir Suður- og Vesturlandi. Í leiðöngrum haustið 2021 fengust um 300 brislingar, nokkrir við Suðurland og í Faxaflóa en flesti...

Otolith shape has previously been used to identify ecotypes within the Icelandic cod ( Gadus morhua) stock, using DST profiles to validate the results. Fish otolith shape variation has repeatedly been found to be largely determined by growth rate. To examine the effect of growth rate on the relationship between otolith shape and cod ecotypes (using...

Migration and behaviour of Icelandic cod Tagging studies have been used to study migration of Icelandic cod since 1904. Results from data storage tags (DSTs) have revealed two different behaviour patterns, coastal cod that mainly inhabits coastal waters shallower than 200 m and frontal cod migrating to offshore frontal areas during the feeding peri...

Farið er yfir framkvæmd og helstu niðurstöður stofnmælingar hrygningarþorsks með þorskanetum (SMN, netarall) sem fór fram í 26. sinn dagana 25. mars til 27. apríl 2021. This report describes the implementation and main results of the gillnet survey of spawning cod in Icelandic waters (SMN) carried out for the 26th time between 25 March and 27 Apri...

Gerð er grein fyrir framkvæmd og helstu niðurstöðum stofnmælingar botnfiska á Íslandsmiðum sem fram fór dagana 1.‐23. mars 2021. Niðurstöður eru bornar saman við fyrri ár, en verkefnið hefur verið framkvæmt með sambærilegum hætti ár hvert frá 1985. The report describes the implementation and main results of the Icelandic Groundfish Survey, carrie...

Otolith shape has previously been used to identify ecotypes within the Icelandic cod (Gadus morhua) stock, using DST profiles to validate the results. Fish otolith shape variation has repeatedly been found to be largely determined by growth rate. To examine the effect of growth rate on the relationship between otolith shape and cod ecotypes (using...

This report describes the implementation and main results of the Icelandic autumn groundfish survey, carried out between 9 October and 2 November 2020. This standardized survey has been conducted annually since 1996 and the present results are compared with those of previous years.

Marine biota are redistributing at a rapid pace in response to climate change and shifting seascapes. While changes in fish populations and community structure threaten the sustainability of fisheries, our capacity to adapt by tracking and projecting marine species remains a challenge due to data discontinuities in biological observations, lack of...

Marine biota are redistributing at a rapid pace in response to climate change and shifting seascapes. While changes in fish populations and community structure threaten the sustainability of fisheries, our capacity to adapt by tracking and projecting marine species remains a challenge due to data discontinuities in biological observations, lack of...

The distributional response of marine fishes to climate warming would be expected to be very different than that of homeothermic birds and mammals, due both to more direct thermal effects on poikilothermic fish physiology and on reduced habitat fragmentation. In this study, we use a combination of linear models and graphical tools to quantify three...

Marine biota is redistributing at a rapid pace in response to climate change and shifting seascapes. While changes in fish populations and community structure threaten the sustainability of fisheries, our capacity to adapt by tracking and projecting marine species remains a challenge due to data discontinuities in biological observations, lack of d...

The report describes the implementation and main results of the Icelandic Groundfish Survey, carried out between 27 February and 20 March 2020. This standardized survey has been conducted annually since 1985 and the present results are compared with those of previous years.

Handbók um stofnmælingu botnfiska á Íslandsmiðum sem hófst 27. febrúar 2020. Lýst er framkvæmd verkefnisins, m.a. umfangi gagnasöfnunar, hvernig safna eigi líffræðilegum upplýsingum, skráningu mælinga, veiðarfæri og veiðiaðferðum. Einnig eru fyrirmæli um það hvernig aðferðum skuli beitt við tog og gefnar nákvæmar staðsetningar og aðrar upplýsingar...

Aim Previous analyses of marine fish species richness based on presence‐absence data have shown changes with latitude and average species size, but little is known about the underlying processes. To elucidate these processes we use metabolic, neutral and descriptive statistical models to analyse how richness responds to maximum species length, fish...

Gerð er grein fyrir helstu niðurstöðum Stofnmælingar botnfiska að haustlagi sem fram fór dagana 26. september til 3. nóvember 2019. Niðurstöður eru bornar saman við fyrri ár, en verkefnið hefur verið framkvæmt með sambærilegum hætti frá 1996.

Nýliðun er lykilþáttur varðandi viðgang fiskistofa. Upplýsingar um nýliðun eru mikilvægar í stofnmati enda segja þær til um fjölda einstaklinga sem bætast munu við stofna og veiðar á komandi árum. Hrygningarstofn þorsks við Ísland hefur farið stækkandi á síðustu árum en á sama tíma hafa fáir sterkir árgangar þorsks komið inn í stofninn. Í þessari s...

A fundamental challenge in ecology is to understand why species are found where they are and predict where they are likely to occur in the future. Trait-based approaches may provide such understanding, because it is the traits and adaptations of species that determine which environments they can inhabit. It is therefore important to identify key tr...

Tvö af tegundaríkustu fiskasamfélögum í hafinu umhverfis Ísland má finna á miklu dýpi í landgrunnshallanum fyrir vestan og suðaustan landið. • Dökkháfur (Etmopterus princeps) og svartháfur (Centroscyllium fabricii) og eru djúpsjávartegundir af dökkháfaaett (Etmopteridae) sem tilheyra þessum samfélögum og eru þeir algengir í haustralli Hafrannsóknas...

Farið er yfir framkvæmd og helstu niðurstöður stofnmælingar hrygningarþorsks með þorskanetum (netarall) sem fór fram í 24. sinn dagana 25. mars til 29. apríl 2019.

Gerð er grein fyrir framkvæmd og helstu niðurstöðum stofnmælingar botnfiska á Íslandsmiðum sem fram fór dagana 26. febrúar til 20. mars 2019. Niðurstöður eru bornar saman við fyrri ár, en verkefnið hefur verið framkvæmt með sambærilegum hætti ár hvert frá 1985.

Homing and site fidelity of Atlantic wolffish Anarhichas lupus was studied at the main spawning ground and four different feeding grounds in Icelandic waters. A total of 883 fish were tagged with T-bar anchor tags, whereof 349 fish also received an internally implanted data storage tag (DST). The DSTs data revealed consistent year-to-year migration...

Knowing movement and structure of fish populations is a prerequisite for effective spatial fisheries management. The study evaluates migration patterns and connectivity of two groups of cod (Gadus morhua) associated with offshore feeding and nursery grounds. This was achieved by investigating (i) migration pathways of cod tagged at the feeding area...

One of the major goals in biogeography is describing and understanding species distributions. However, when focusing on taxonomy one may miss the mechanistic understanding of what underlies these distributions. Trait-based ecologists argue that traits are useful in explaining where species occur, since it is the traits that determine how species re...

Changes in stock size of a top predator have been found to cascade through the trophic levels but the mechanism has not been fully clarified. Using data from annual trawl surveys within a fjord during 1988-2015, we present evidence that changes in abundance of cod Gadus morhua and haddock Melanogrammus aeglefinus have an immediate effect on the dis...

The report presents methods and results of an annual flatfish survey in the bay of Faxaflói, SW Iceland, in 1995-2013. The main objective of the project was to study size composition, age, abundance and distribution of plaice (Pleuronectes platessa) and dab (Limanda limanda) in the bay, before the initiation of the seasonal demersal seine fishery....

Aim The life history of a species is determined by trade‐offs between growth, survival and reproduction to maximize fitness in a given environment. Following a theoretical model, we investigate whether the composition of marine fish communities can be understood in terms of a set of life‐history strategies and whether the prevalence of the strategi...

https://www.hafogvatn.is/static/research/files/fjolrit-182pdf

The study analyses the home ranges and spatial segregation of spawning components of Icelandic cod Gadus morhua based on: (1) conventional tag (CT) recaptures and (2) depth, temperature and tidal locations from electronic data storage tags (DSTs). A total of 5987 CT recapture positions from tagging in geographically distinct spawning grounds from 1...

https://www.hafogvatn.is/static/research/files/fjolrit-176pdf

In recent years, about one-third of the cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) catches in Icelandic waters have been obtained with longline. Although longlining has been regarded as a conservation-oriented fishing method, a serious drawback of this fishing gear is the high catches of undersized fish. Our purpose was to locate are...

Most species living in the warmer waters showed an upward trend in abundance following warming in 1996 and a clockwise distributional shift along the shelf. For many of these species, however, this response was not immediate but became evident in the warm years that followed. For the last 4-6 years there has been a significant influx of previously...

The interaction between two species of gadoid and a shrimp stock was studied in a 40 km long two-armed fjord in north-west Iceland. On the basis of acoustic and trawl surveys in 2005 and 2006, immature cod Gadus morhua and haddock Melanogrammus aeglefinus were found to migrate to the inner part of the fjord in late summer, concurrent with rising te...

Björnsson, B., Karlsson, H., Thorsteinsson, V., and Solmundsson, J. 2011. Should all fish in mark–recapture experiments be double-tagged? Lessons learned from tagging coastal cod (Gadus morhua). – ICES Journal of Marine Science, 68: . Cod (Gadus morhua) were tagged outside and inside “herds” formed by anthropogenic feeding in an Icelandic fjord. Re...

The abundance and distribution of monkfish (Lophius piscatorius) at Iceland have increased rapidly in the last decade, concurrent with rising seawater temperatures and salinity. These environmental changes seem to have improved the reproductive success of the monkfish stock, and since 1998 large cohorts have recruited almost annually, in great cont...

Schopka, S. A., Solmundsson, J., Ragnarsson, S. A., and Thorsteinsson, V. 2010. Using tagging experiments to evaluate the potential of closed areas in protecting migratory Atlantic cod (Gadus morhua). – ICES Journal of Marine Science, 67: 1024–1035. About 5200 cod (Gadus morhua) were tagged on three fishing grounds and within two marine protected a...

The density and mean size of demersal fish were analysed inside and outside three protected areas off the northern coasts of Iceland. One-way ANCOVA and mixed effects models, with depth, bottom temperature and tow duration as covariates, were used to determine differences in the two metrics between areas. In general, these differences were not stat...

Previous work has identified maximum body size as an important functional life-history trait for marine fish species influencing their growth, natural mortality, recruitment, and resilience to exploitation. We use data from a large number of scientific bottom trawl surveys from West Greenland to the Adriatic Sea to compare the distribution of speci...

Manuals describing the methodology of bottom trawl surveys in Icelandic waters are published annually by the Marine Research Institute. The manuals describe the extent of data collection, provide instructions on sampling of biological variables, registration of information, the survey fishing gear and fishing methods. They provide instructions on t...

Elevated ocean temperatures have been predicted to lead to a poleward shift in the latitudinal distribution ranges of fish species. Different responses of fish species to increased temperatures might lead to changes in assemblage structure and local species richness. In this study, the assemblage structure and diversity of groundfish in Icelandic w...

This study describes recent changes in the spatial distribution and abundance of monkfish in Icelandic waters, based mostly on data collected from the Icelandic groundfish survey (IceGFS) that has been conducted annually since 1985 during the month of March. The stock size of monkfish appears to have been increasing rapidly since 1998 and the speci...

The feeding habits of Greenland halibut (Reinhardtius hippoglossoides) in Icelandic waters were investigated. In total, 1595 Greenland halibut were collected during the period from May 1991 to March 1992. The main prey species were capelin (Mallotus villosus), eelpouts (Lycodes spp.), northern ambereye (Hymenodora glacialis) and northern shrimp (Pa...

Jonasson, J. P., Thorarinsdottir, G., Eiriksson, H., Solmundsson, J., and Marteinsdottir, G. 2007. Collapse of the fishery for Iceland scallop (Chlamys islandica) in Breidafjordur, West Iceland. – ICES Journal of Marine Science, 64: 298–308. The stock index of the Iceland scallop (Chlamys islandica) in Breidafjordur on the west coast of Iceland has...

The feeding ecology of the European shag (Phalacrocorax aristotelis) and the great cormorant (P. carbo) in Iceland was studied. These bird species may affect their marine environment, for instance, by predating on several commercially important fish species in coastal waters. The shag and cormorant diets were studied throughout the year in the peri...

The effect of reduced fishing effort on the demersal fish community, following area closures in 1993, was analysed for two protected areas off the east coast of Iceland, Digranesflak and Breiddalsgrunn. The data were collected using a standardized bottom trawl during groundfish surveys in the period 1985–2004. The aspects of the fish community that...

About 2200 plaice (Pleuronectes platessa) were tagged on spawning and feeding grounds off Iceland. The aim was to reveal the migration pattern of mature plaice and to estimate fidelity rates to spawning and feeding grounds. From a total of 183 plaice tagged on the spawning ground and recaptured in successive spawning seasons, 91% of males and 88% o...

The vertical and horizontal movements of mature plaice (Pleuronectes platessa) on spawning grounds west of Iceland were studied, using conventional anchor tags and electronic data storage tags measuring depth and temperature at specified time intervals. Concurrent to the taggings, information on sex ratios, maturation and spawning was analyzed usin...

We used surveillance radar to track flocks of colonially breeding alcids at Latrabjarg, northwest Iceland, that were returning from their feeding grounds. We compared the flight directions of incoming flocks during the chick-rearing period with alcid densities at sea during both the incubation and chick-rearing periods. The direction of incoming fl...

We used surveillance radar to track flocks of colonially breeding alcids at Latrabjarg, northwest Iceland, that were returning from their feeding grounds. We compared the flight directions of incoming flocks during the chick-rearing period with alcid densities at sea during both the incubation and chick-rearing periods. The direction of incoming fl...

1. The size of body organs shows adaptive temporal variation in many animal species. The variation in the size of body organs was examined to see if it is also a component of local adaptation to geographical variation in ecological conditions. 2. Major body organs were measured in five species of Icelandic seabirds, sampled from two areas where bir...

Stable-nitrogen and carbon isotope ratios (delta(15)N and delta(13)C) were determined in liver tissue samples from six species of Icelandic seabirds. Stomach contents were primarily capelin (Mallotus villosus) in north Iceland, and primarily sandlance (Ammodytes sp.) in south Iceland. Stable isotope signatures also were measured in a range of typic...

The massive expansion in breeding numbers and range of the northern fulmar Fulmarus glacialis over the last two centuries is generally attributed to an increased availability of fish offal and discarded fishes from commercial fisheries. This implies that discards should be a major component in fulmar diets in the more recently colonised areas in th...

The massive expansion in breeding numbers and range of the northern fulmar Fulmarus glacialis over the last two centuries is generally attributed to an increased availability of fish offal and discarded fishes from commercial fisheries. This implies that discards should be a major component in fulmar diets in the more recently colonised areas in th...

The diet of the six most numerous seabird species found in Iceland was investigated during the summers of 1994 and 1995. A total of 1481 stomachs was analysed from common guillemots (Uria aalge), Brü nnich's guillemots (U. lomvia), razorbills (Alca torda), puffins (Fratercula arctica), kittiwakes (Rissa tridactyla), and northern fulmars (Fulmarus g...