Norwegian Institute of Marine Research

About: Norwegian Institute of Marine Research is a facility organization based out in Bergen, Hordaland, Norway. It is known for research contribution in the topics: Population & Gadus. The organization has 167 authors who have published 180 publications receiving 5117 citations. The organization is also known as: Havforskningsinstituttet & Institute of Marine Research.

Perspectives on ecosystem-based approaches to the management of marine resources

Abstract: Marine Protected Areas (MPAs) include many subclasses (e.g. marine sanctuaries, marine parks, wildlife refuges, fisheries closures, no-take MPAs, multiple-use MPAs, marine reserves, ecological reserves) all of which can be defined based mainly upon the level of protection and the primary conservation goal (see www.mpa.gov; Lubchenco et al. 2003). MPAs, and especially the marine reserves subclass (i.e. ‘areas of the ocean completely protected from all extractive and destructive activities’; Lubchenco et al. 2003) represent the extreme case of the precautionary approach to managing marine resources (e.g. Lauck et al. 1998). The strong and rapidly growing interest in MPAs (and particularly in marine reserves) is reflected in the dramatic increase in the number of publications devoted to them (reviewed in Jones 2002, Gell & Roberts 2003, and the articles in ‘The Science of Marine Reserves ’, a supplemental issue of Ecological Applications, Vol 13, Iss 1, freely available for download at www.esa-journals.org/esaonline/?request=getstatic&name=s1051-0761-013-01-0001). In addition, there are now a number of sites on the World Wide Web that are either totally devoted to MPAs, or include relevant information on them: UNEP’s World Conservation Monitoring Centre (www.unep-wcmc.org/ protected_areas), the Partnership for Interdisciplinary Studies of Coastal Oceans (PISCO, www. piscoweb.org), and several others. This intense interest is at least partly related to MPAs having been identified and advocated as a conservation (of habitat and biodiversity) and managerial (of fisheries) tool of central importance in the Ecosystem Approach to Fisheries (EAF) (e.g. Agardy 2000, Stergiou 2002, Halpern & Warner 2003, Lubchenko et al. 2003, Pauly & MacLean 2003, Hilborn et al. 2004). It is hoped that MPAs will be beneficial in (1) rebuilding overexploited fish stocks, (2) preserving habitat and biodiversity, (3) maintaining ecosystem structure, (4) buffering against the effects of environmental variability, (5) serving as a control group against which populations in exploited regions can be compared, among others. Clearly, the choice of location, spatial extent (horizontal and vertical), and number of MPAs is critical if they are to meet these goals. It is to this issue that we devote our attention here. Halpern & Warner (2003) state, ‘Most reserve locations and boundaries were drawn by a political process that focused on economics, logistics, or public acceptance, while largely overlooking or ignoring how the complex ecology and biology of an area might be affected by reserve protection.’ In this sense, establishing the locations and boundaries of MPAs can be seen as analogous to the imperfect process associated with establishing stock management grids—a process that has never really managed to incorporate the key realities of population dynamics of the exploited species. While there is a growing consensus on the need for MPAs, at this point in time there is no clear and well-founded basis upon which their location, spatial extent and number can be decided. In fact, rationales/frameworks that are based upon principles of theoretical and applied ecology have only recently been tapped to address these key questions (e.g. Roff & Evans 2002, Botsford et al. 2003, Roberts et al. 2003a,b, Shanks et al. 2003, Fisher & Frank 2004). Much of this work focuses on the manner in which different aspects of the life histories of marine organisms—spawning locations, dispersal, larval retention and export, juvenile nursery areas, etc.—affect MPA design. In this context, we contend that an ecoevolutionary framework already exists, grounded in marine ecology and fisheries oceanography, that is completely consistent with EAF and MPA objectives. The Member-Vagrant Hypothesis as a framework for defining the location, size and number of MPAs. The Member-Vagrant Hypothesis (MVH), the development of which can be traced through a series of publications by Mike Sinclair and Derek Iles (Iles & Sinclair 1982, Sinclair 1988, 1992, Sinclair & Iles 1988, 1989), defines 4 attributes of populations that are involved in the regulation of their size. The ’population richness’ refers to the number of discrete self-sustaining populations (henceforth simply ’populations’) exhibited by any given species. Species such as herring, cod, mackerel, the salmonids, and many others are population rich. The ‘spatial pattern’ relates to the geographic distribution of these populations. Population rich species are usually also broadly distributed (the north Atlantic region is so far the best studied in this regard). Population richness and spatial pattern are species-level characters. The ’absolute abundance’ refers to the instantaneous size of the various populations of any given species, and this size—which can range over several orders of magnitude—varies over time (thus, its ’temporal variability’). These last 2 components of the MVH are population-level characteristics. Sinclair & Iles have applied the MVH to describe the richness, pattern, abundance and variability of several economically im271

Drift, growth, and survival of larval Northeast Arctic cod with simple rules of behaviour

Abstract: Due to vertical variations in ocean circulation, larval Northeast Arctic cod Gadus morhua may influence their own drift routes by migrating vertically. By coupling a larval individual- based model and a general circulation model, we simulated larval vertical positioning according to simple rules based on individual risk sensitivity. This enabled us to investigate how larval growth, survival and horizontal distribution vary between individuals following different rules. Immediate depth selection follows from the rules, with implications for environmental exposure and instanta- neous growth rates. The behavioural rules had long-term and large-scale consequences, since verti- cal positioning influences the drift trajectory of the larva, and thereby the physical environment the larva experiences along its way. Two alternative rule formulations were explored, each containing the full range of strategies, from maximising immediate growth to maximising immediate survival. Fitness was defined as accumulated survival probability up to 18 mm for larvae released at 2 impor- tant spawning grounds in the Lofoten area. Both rules gave better fitness than for individuals drifting at fixed depths. The most successful individuals performed active vertical migration and had an inter- mediate risk sensitivity. When risk sensitivity was allowed to change with ontogeny, larvae that first emphasised growth and then changed to intermediate risk sensitivity were the most successful ones, although improvements were minor compared to fixed sensitivities. The 2 spawning grounds led to slight differences in fitness, but success as a result of risk sensitivity was similar at both, suggesting that optimal larval strategies may be robust across different spawning grounds.

An operational system for processing and visualizing multi-frequency acoustic data

Abstract: Calibrated and digitized data from two or more discrete echosounder frequencies can be combined for the purpose of separating and extracting the acoustic scattering from zooplankton and fish in mixed recordings. This method is also useful for quantifying the relative contribution of each frequency to the total acoustic-backscattering when scrutinizing records in large-scale, acoustic surveys. Echosounder hardware requirements are defined which would permit the ideal extraction of such information. These include calibration, transducer specification, pulse resolution and digital representation of the signals. During this initial study a special version of the Simrad EK500 multi-frequency, split-beam echosounder and the Bergen Echo Integrator (BEI) post-processing system were used. The echosounder transmitted pulses simultaneously at four frequencies, 18, 38, 120 and 200 kHz and transferred the received signals to the post-processing system in calibrated, raw, digitized format. Methods are described for echogram manipulation and for the construction of new, synthetic, combined-frequency [c(f)] echograms. Examples of extracted scattering information from mixed layers of fish and small scattering-organisms, such as copepods and euphausiids, are shown, and the potential of the method is discussed.

Functional responses in polar bear habitat selection

Abstract: Habitat selection may occur in situations in which animals experience a trade-off, e.g. between the use of habitats with abundant forage and the use of safer retreat habitats with little forage. Such trade-offs may yield relative habitat use conditional on the relative availability of the different habitat types, as proportional use of foraging habitat may exceed proportional availability when foraging habitat is scarce, but be less than availability when foraging habitat is abundant. Hence, trade-offs in habitat use may result in functional responses in habitat use (i.e. change in relative use with changing availability). We used logistic and log-linear models to model functional responses in female polar bear habitat use based on satellite telemetry data from two contiguous populations; one near shore inhabiting sea ice within fjords, and one inhabiting pelagic drift ice. Open ice, near the ice edge, is a highly dynamic habitat hypothesised to be important polar bear habitat due to high prey availability. In open ice-polar bears may experience a high energetic cost of movements and risk drifting away from the main ice field (i.e. trade off between feeding and energy saving or safety). If polar bears were constrained by ice dynamics we therefore predicted use of retreat habitats with greater ice coverage relative to habitats used for hunting. The polar bears demonstrated season and population specific functional responses in habitat use, likely reflecting seasonal and regional variation in use of retreat and foraging habitats. We suggest that in seasons with functional responses in habitat use, polar bear space use and population distribution may not be a mere reflection of prey availability but rather reflect the alternate allocation of time in hunting and retreat habitats.

Immune response to a recombinant capsid protein of striped jack nervous necrosis virus (SJNNV) in turbot Scophthalmus maximus and Atlantic halibut Hippoglossus hippoglossus, and evaluation of a vaccine against SJNNV.

Abstract: Immunisation by intraperitoneal injection of an oil-emulgated recombinant partial cap- sid protein (rT2) from striped jack nervous necrosis virus (SJNNV) was performed on adult turbot Scophthalmus maximus and Atlantic halibut Hippoglossus hippoglossus. A specific humoral immune response was recorded in both species, and the levels of rT2-specific antibodies increased markedly in all groups during the 20 wk experiment. A challenge model for SJNNV was established by intra- muscular injection of juvenile turbot. The turbot developed viral encephalopathy and retinopathy (VER), also known as viral nervous necrosis (VNN), with cumulative mortality in the range of 25 to 66%, after intramuscular inoculation with SJNNV propagated in the striped snake head cell line (SSN-1). Although neither clinical signs nor mortality were registered, SJNNV was neuroinvasive after bath exposure. The infection after both modes of challenge was verified by means of immuno- histochemistry and RT-PCR, and SJNNV was reisolated in cell culture. The results indicate that SJNNV may have entered the central nervous system (CNS) by axonal transport through motor nerves after intramuscular inoculation. A vaccine efficacy test was performed on juvenile turbot, employing oil emulsified rT2 as a test vaccine and intramuscular inoculation of SJNNV. Significant protection was observed when the challenge was performed 10 wk post-vaccination.