Anne G V Salvanes

• University of Bergen

This study investigates how marine sediment proxies reflect dissolved oxygen levels in fjord basin water to improve our understanding of coastal marine deoxygenation that has been associated with ongoing climate change. We use western Norwegian fjords to test how marine sediment proxies for dissolved oxygen perform. Such knowledge is needed to eval...

Marine community sensitivity to climate change can be informed by examining community patterns along current environmental gradients. Fjords provide natural laboratories for such studies due to their variable oceanographic conditions that can differ from basin to basin. Bottom trawl samples were collected from 17 fjord basins and nearshore coastal...

Fjords provide valuable research opportunities for marine scientists. They are excellent natural infrastructure for climate impact studies associated with hypoxic episodes and consequences for mesopelagic and deep‐sea ecosystems involving oceanographic circulation processes and basin water renewals. Repeated sampling from the same populations is po...

The mesopelagic fish Benthosema glaciale [Actinopterygii: Myctophiformes: Myctophidae], abundant in open ocean and deep fjords, is targeted for future exploitation despite existing knowledge gaps on population vital rates. Among these gaps, the vulnerability to pathogens is poorly understood. Parasites rely on the metabolic energy of their host and...

Fishes inhabiting the mesopelagic zone of the world's oceans are estimated to account for the majority of the world's fish biomass. They have recently attracted new attention because they are part of the biological carbon pump and have been reconsidered as a contribution to food security. Hence, there is an urgent need to understand how environment...

The glacier lanternfish Benthosema glaciale is a key myctophid with a wide distribution in the northern Atlantic. It is a species that has a strong vertical migration capacity and have the potential to move between the surface waters and mesopelagic depths in a diel cycle (DVM), mainly depending on ambient light conditions. We investigated the feed...

The deep-sea is rapidly losing oxygen, with profound implications for marine organisms. Within Eastern Boundary Upwelling Systems, such as the California and the Benguela Current Ecosystems, an important question is how the ongoing expansion, intensification and shoaling of Oxygen Minimum Zones (OMZs) will affect deep-sea fishes throughout their li...

Harvesting is typically size-selective, targeting large individuals. This is expected to lead to reduced average body size and earlier maturation (i.e. faster life histories). Such changes can also affect traits seemingly unrelated to harvesting, including immunocompetence. Here we test four hypotheses on how harvesting affects immunocompetence bas...

To understand the predator–prey interactions during this transitional migration, we tracked 22 Atlantic salmon (Salmo salar) smolts and their most prevalent predator, brown trout (Salmo trutta) (N = 21), and recorded their depth use in a basin of Lake Evanger, Norway, with acoustic telemetry during May 2020. Both salmon smolts (mean ± SD: 3.8 ± 3.3...

Ghost crabs (Ocypode sp.) are important bioturbators in coastal deserts in subtropical and tropical regions and contribute to the transfer of energy from the ocean and to wild animals in the dunes of the deserts further inland. However, threats to the ghost crab habitats are rising due to increased use of their beach habitat as recreational areas a...

Smolt migration through lakes is hazardous, as the predation pressure can be extreme and the hydrology a great contrast to that of a riverine area. However, the mechanisms yielding these challenges have been scarcely investigated. We conducted an acoustic telemetry field study in Lake Evangervatnet, Voss, Norway, utilising Vemco V5 predation tags....

The epoch of the Anthropocene, a period during which human activity has been the dominant influence on climate and the environment, has witnessed a decline in oxygen concentrations and an expansion of oxygen depleted environments in both coastal and open ocean systems since the middle of the 20th century. This paper provides a review of system-spec...

The epi- and mesopelagic ecosystems of four sub-polar ocean basins, the Labrador, Irminger, Iceland and Norwegian seas, were surveyed during two legs from Bergen, Norway, to Nuuk, Greenland, and back to Bergen. The survey was conducted from 1 May to 14 June, and major results were published in five papers (Drinkwater et al., Naustvoll et al., Stran...

The bearded goby Sufflogobius bibarbatus is an abundant endemic small fish species on the continental shelf of the northern Benguela. The goby habitat is characterised by generally low bottom oxygen concentrations that vary spatially and seasonally. In the present study of population structure, 13 samples of S. bibarbatus from inner and outer shelf...

The bearded goby Sufflogobius bibarbatus is an abundant endemic small fish species on the continental shelf of the northern Benguela. The goby habitat is characterised by generally low bottom oxygen concentrations that vary spatially and seasonally. In the present study of population structure, 13 samples of S. bibarbatus from inner and outer shelf...

Distribution of micronekton was investigated during early summer of 2013, using data from a cruise covering the central parts of four north Atlantic basins, the Norwegian Sea (NS), Iceland Sea (ICS), Irminger Sea (IRS), and Labrador Sea (LS). Continuous underway acoustics mapped vertical and horizontal distributions, and trawl sampling provided dat...

Previous studies have shown decline in dissolved oxygen of the ocean basins. A hypothesis for this development is that ocean warming through increased stratification has caused reduced ventilation of the interior ocean. Here we provide evidence that reduced ventilation, which has been associated with a 1 °C warming of the North Atlantic Water (NAW)...

The bearded goby (Sufflogobius bibarbatus), a key species in the northern Benguela Upwelling Ecosystem, tolerates extremely low levels of oxygen. Yet little is known about how its reproduction is affected by these harsh living conditions. The distribution patterns of alternative reproductive tactics of male bearded goby across the continental shelf...

Hypoxia [O 2 < 2.0 mL L À1 (87 lmol kg À1)] and severely hypoxic water masses [O 2 < 0.5 mL L À1 (21.8 lmol kg À1)] are increasing in coastal marine ecosystems due to eutrophication and warming. Here, we investigate the response of the suboxic-tolerant endemic fish, Sufflogobius bibarbatus, to variations in the thermal and oxygen environment, as we...

Data on developmental characteristics from fertilization to 2 days post-hatching during captivity of the anoxia tolerant bearded goby Sufflogobius bibarbatus, one of the keystone prey species for many of the commercial fish populations, sea mammals and birds in south-west Africa, are presented.

Different kinds of experience during early life can play a significant role in the development of an animal's behavioural phenotype. In natural contexts, this influences behaviours from anti-predator responses to navigation abilities. By contrast, for animals reared in captive environments, the homogeneous nature of their experience tends to reduce...

The process of stock enhancement, where large numbers of fish are reared and then released, is an increasingly common practice aimed at improving the numbers of fish in rivers, lakes and along coasts. Stock enhancement practices, however, raise a number of welfare issues both for fish that are reared within captivity, and for the local populations...

The environment can play an important role in shaping how an animal behaves, and how well the animal performs in a particular environment can be influenced by early experiences. The tradition of releasing captive-reared juveniles into the wild in an effort to strengthen wild fish populations has often had little success owing to high post-release m...

The frequency of low O2 (hypoxia) has increased in coastal marine areas but how fish avoid deleterious water masses is not yet clear. To assess whether the presence and oxygen pressure (PO2) level of an O2 refuge affects the hypoxia avoidance behaviour of fish, individual Atlantic cod (Gadus morhua L.) were exposed to a range of O2 choices in a 2-w...

Nutrient-rich, upwelling marine areas with high productivity often produce sediments dominated by organic-rich mud. Here, intense decay processes create hypoxic conditions with high concentrations of hydrogen sulphide and methane in the muddy surface layers. Such environments are inhospitable to most forms of life and those organisms that can survi...

Fourteen polymorphic microsatellite markers with tetranucleotide repeats were developed for the bearded goby (Sufflogobius bibarbatus) from partial genomic DNA libraries using a repeat enrichment protocol, and characterized using two putative populations from the northern Benguela. The average number of alleles per locus ranged from 4 to 34, and th...

The frequency of low O2 (hypoxia) has increased in coastal marine areas but how fish avoid deleterious water masses is not yet clear. To assess whether the presence and oxygen pressure (PO2) level of an O2 refuge affects the hypoxia avoidance behaviour of fish, individual Atlantic cod (Gadus morhua L.) were exposed to a range of O2 choices in a 2-w...

Studies of contest competition between wild and farmed fish have mostly focused on fish with strongly territorial behaviour. Little is known about species with more plastic social behaviour, such as Atlantic cod (Gadus morhua L.), a species that can either aggressively defend territories or shoal. There is also concern that cod that escape from far...

Since the collapse of the pelagic fisheries off southwest Africa in the late 1960s, jellyfish biomass has increased and the structure of the Benguelan fish community has shifted, making the bearded goby (Sufflogobius bibarbatus) the new predominant prey species. Despite increased predation pressure and a harsh environment, the gobies are thriving....

SummaryPCR-RFLP analysis of mitochondrial DNA (NADH-3/4 gene and the control region) of the Benguelan bearded goby Sufflogobius bibarbatus revealed weak, but significant genetic differentiation (overall FST = 0.137) that could not be predicted by hydrodynamics alone, thus warranting further investigations to understand the forces behind population...

The mesopelagic fish Benthosema glaciale was found to be widely distributed in the Norwegian Sea and several west Norwegian fjords, but mostly absent above the continental shelf. Areas with bottom depths of less than 300 m were almost totally devoid of B. glaciale. There were significant differences in allozyme frequencies and growth between fjords...

IntroductionSpecifying Individuals in IBMsFeatures of Individual—Based ModelsFormulating and Testing IBMSReview of Individual—Based Models in Fisheries BiologyConclusions AcknowledgementsReferences

Hypoxia can influence fish growth, survival and on larger scales, population structure. These effects may be influenced by water temperature, and may vary intra-specifically with genotype. In Atlantic cod (Gadus morhua L.), the two haemoglobin homozygotes (Hb-I⁎11 and Hb-I⁎22) vary in oxygen affinity at different temperatures, which is thought to c...

Spawning time and areas, and the length of the spawning season of shallow-water (Merluccius capensis) and deep-water (M. paradoxus) hake, were investigated from bottom trawl collections taken in Namibian waters between September 1998 and October 2000 and from August to November 2001. The gonadosomatic index (GSI) and the incidence of advanced matur...

Animals that undergo a habitat shift face a number of challenges as they move between habitats; for example, they may encounter new predator species and may be vulnerable as they adapt to their new surroundings. An ability to adapt quickly to the new environment is likely to influence post-transition survival, and an understanding of the developmen...

Mqoqi, M., Lipiński, M. R., and Salvanes, A. G. V. 2007. The ecology of Sepia australis (Cephalopoda: Sepiidae) along the south coast of South Africa. – ICES Journal of Marine Science, 64: 945–955.The influence of abiotic factors (depth, region, temperature, salinity, and oxygen) on the abundance of the cuttlefish Sepia australis was investigated u...

Many re-introduction programs used for conservation of populations and species threatened with extinction advocate the use of enriched rearing environments to train animals how to behave appropriately in the wild. Curiously, most of the current fish re-stocking programs have paid little attention to lessons previously learned in bird and mammal re-...

The release of hatchery-reared fishes for restoring threatened and endangered populations is one of the most controversial issues in applied ecology. A central issue has been to determine whether releases cause extinction of local wild populations. This may arise either through domesticated or non-local fishes hybridizing with wild fishes, or throu...

After its collapse in the late 1960s, 1991 was the first year of systematic herring investigations after the Norwegian Sea stock returned to the traditional summer-feeding areas. Of 11 prey groups three dominated the diet; Calanus finmarchicus, Parathemisto spp. and Sebastes spp. There was a high prevalence of Ichthyophonus sp. at stations in the c...

Life history parameters are compared for populations of Maurolicus muelleri from Norwegian fjords and the Norwegian Sea in 1995 and 1996. The mortality rate was higher in the oceanic population (2·55 for males, 2·00 for females) than in the fjords (1·15 for males, 0·97 for females). Fish from the Norwegian Sea population occupied a depth with highe...

An experiment was conducted to examine (a) the effects of photoperiod on timing of sexual maturation (b) the relationship between plasma steroid levels, appetite and growth in male and female Atlantic cod (Gadus morhua L.). Wild caught Norwegian coastal cod were subjected to either a 6L/18D photoperiod typical of January at 60N-(Short day group) or...

This study provides evidence of countergradient variations in life-history traits among coastal cod Gadus morhua off the Norwegian coast, suggesting the existence of sub-populations. One-yr-old wild-caught individuals from 70°N were smaller, grew slower, weighed less, and had a lower condition factor (CF) than southern cod from 60°N during the samp...

This study provides evidence of countergradient variations in life-history traits among coastal cod Gadus morhua off the Norwegian coast, suggesting the existence of sub-populations. One-yr-old wild-caught individuals from 70° N were smaller, grew slower, weighed less, and had a lower condition factor (CF) than southern cod from 60° N during the sa...

We housed offspring from northern (70° N) and southern (60° N) coastal cod (Gadus morhua) together in a ‘common garden’ rearing experiment at a temperature and light regime representative of the southern population. Through a more active feeding behaviour and a higher success, the northern cod achieved a larger food share and a higher growth rate a...

Restocking fish species may be one way to overcome problems of overfishing or dwindling natural populations. To date, most restocking programs have failed. We believe that these failures are, in part, due to the sparse, uniform rearing environment that fails to teach the fish about heterogeneity. We report experiments in which the early rearing env...

It is hypothesised that the fjords with restricted water circulation may partially isolate fish populations living there. The pelagic life history stages of the mesopelagic lanternfish may potentially subject to dispersal over vast areas, preventing population subdivision. In the present paper, we test the hypothesis of no geographic population gen...

To succeed in scramble competition for food an individual fish will have to have characteristics that allow it to respond rapidly to encountered prey. A trait such as metabolic rate, which has a positive effect on oxygen consumption and growth rate, is likely to be positively correlated with the traits that determine the speed of reaction. An impor...

Atlantic cod have been a primary target for marine stock enhancement since the 1880s. In the early part of this period, hatched larvae were released in Norway, the USA and Canada. The last larval releases were conducted in Norway in 1971, and a century of cod larvae releases were halted without any clear evidence of benefit. Since the early 1980s,...

The Bergen Ocean Model (BOM), a three-dimensional physical coastal ocean model, was used for a numerical simulation experiment to investigate short-term effects of wind-generated coastal upwelling and downwelling on the dynamics of adjacent large outer and smaller inner fjords. The effect of the real alongshore wind regime on advection for an ideal...

Two modeling approaches were used to evaluate the combined responses in a fish population to environmental fluctuations and exploitation. Short-term effects of growth and survival of year classes of cod and the effects of fishing were evaluated by using a modified version of a dynamic ecosystem model (DYNECOMAS II), originally developed for extensi...

First of its kind, this study examines effects of preservatives on otoliths as well as on fish size and weight. Effects of200 days of preservation in 4 % seawater fonnaldehyde solution and 80 % ethanol were investigated for the two small, mesopelagic fishes, Benthosema glaciale (REINHARDT, 1837), and Maurolicus muelleri (GMELIN, 1789). The body wei...

This study uses samples of the mesopelagic fish Maurolicus muelleri (Gmelin) collected in spring 1995 as part of the Norwegian interdisciplinary Mare Cognitum research program. Spatial patterns in life-history parameters such as gonadal developments, fecundity and growth between the Norwegian Sea, coastal areas and Herdlefjorden were studied. Diffe...

A gastric evacuation curve expresses how fast prey disappear from the stomach, and empirical models are used generally for the relationship between weight of prey remaining (Wt) and time (t) after a meal. Unfortunately, empirical models are likely to have restricted applicability because their parameters often represent limited biological mechanism...

This study examines density-dependent mortality of pollack, a major cod predator, and cod, before and after juvenile cod were released on a large scale in Masfjorden, western Norway. The development in stock size, mortality by age group and diet are emphasised, and results for pollack and cod are compared. Population parameters for pollack are esti...

Diet width theory is a branch of optimal foraging theory, used to predict which fractions of the potential food encountered should be pursued. For pelagic fish, it is generally assumed that light is the dominant stimulus for both prey encounter rate and mortality risk. In order to achieve encounter rates allowing selective feeding, the pelagic pred...

To detect possible interactions between the released cod and its predators (large cod and pollack Pollachius pollachius) and competitors (pollack and poor-cod Trisopterus minutus) population characteristics (abundance, growth, condition factor and liver index) were monitored before and after release, in the release area and in a reference area outs...

Synthesizes field and modelling results from a cod enhancement experiment conducted in Masfjorden, W Norway. Large-scale releases of juvenile cod (36 000-90 000 individuals) were undertaken during a period of three years. Three months after release no or minor differences were found concerning feeding, growth and mortality. Cod were very stationary...

The factors determining year-class strength of coastal cod may, even at the juvenile stages (≥3-5 months of age), be sufficiently strong to reduce year classes from strong to weak. The 1988-90 year classes of cod in the fjord were manipulated by release of 27 000-82 500 reared cod at an age of 4-7 months. Abundance, growth, rate condition factor an...

Optimal timing of juvenile releases in extensive cod mariculture can be investigated by adopting a theoretical framework based on evolutionary and ecological relationships. Optimal timing of release will generally be after cod have reached a size at which they settle to the benthic fjord habitat. -from Authors

The fish fauna in the sublittoral habitat of Masfjorden, western Norway, has been studied in order to reveal survival and growth prospects of released juvenile cod in a large-scale stock enhancement experiment. Seasonal changes in abundance of dominating fish species and in the diet of potential competitors and predators to juvenile cod were emphas...

The carrying capacity for cod in a Norwegian fjord was analysed by means of a simulation model. Four age groups of cod were represented as well as the main prey groups labrids, gobies and benthic organisms. These groups made up a near-shore compartment of the model, while nutrients, phytoplankton, herbivorous, carnivorous and gelatinous zooplankton...

This study is a component of a comprehensive ecosystem analysis in connection with a cod enhancement experiment in Masfjorden, western Norway. The main objective was to estimate stock size by age group, recruitment, growth, catches and mortalities both prior to and for the first year after the first large-scale release of juvenile cod, and to study...

The present study analyses the selectivity for cod in two trammel-nets (three-wall nets) and one gillnet (single-wall net) used during an experimental cod fishery conducted monthly from october 1985 to December 1988 in a Norwegian fjord. It is part of a cod enhancement experiment conducted in the fjord. The three nets were grouped and utilized to s...

A gastricevacuationcurveexpresseshow fastpreydisappearfrom thestomach,and empirical models areusedgenerallyfortherelationship between weightofpreyremaining(W t)and time (t)aftera meal. Unfortunately,empiricalmodels are likelyto have restricted applicability becausetheirparametersoftenrepresentlimitedbiological mechanisms . Thispaper developsa simpl...

When captive-bred cod were released for sea ranching in Masfjorden of western Norway, it was evident from field samples that these fish had a different diet and higher mortality rate than wild cod at least the first tree days after release. Moreover, these captive-bred cod were released into the natural habitat in a number that largely exceeded tha...