Albatrossia Research Articles

Life Cycle Characteristics and Distribution of Giant Grenadier Coryphaenoides pectoralis (Macrouridae) in Northwest Bering Sea

The outcomes from the survey research in distribution of the giant grenadier Coryphaenoides pectoralis at different stages of development in the Northwest Bering Sea over 1963–2020 have been reported. The data for 37 thousand catches performed with the bottom and multi-depth trawls at the depths between 0–1200 m are processed. It has been revealed that the species fish tend to spawn throughout the year, with two periods of peak spawning activity in the second half of a spring season and from the late summer season to the first half of an autumn season. The female fish ready to spawn migrate down the water column, keeping deeper than 600 m, where the males ready to spawn are concentrated. After spawning, they come back to the feeding areas of less water depths. The juvenile giant grenadier less than 30 cm in length can be encountered in the mesopaelagic and upper bathypelagic zones, which do not appear to form dense aggregations. The majority of the specimens less than 30–40 cm in length and smaller commonly leave this water column layer to occupy the bottom water layers along the continental shelf. Such differentiation between the juvenils and the sexually mature specimens can provide the opportunity to avoid cannibalism and to use the habitat food sources efficiently.

Estimation of the maximum sustainable yield of giant grenadier <i>Albatrossia pectoralis</i> (Macrouridae) in the Russian Far East using Bayesian surplus production model JABBA

Statistical estimates for the exploitable stock of giant grenadier are determined, by fishing zones in the Russian Far East, and interannual dynamics of the species biomass is considered using historical data on catches and abundance. The assessments relationship with reference points of the biomass dynamic models is examined for the first time. With using the Bayesian approach, a priori assumptions about virgin biomass, which were made earlier on results of scientific surveys extrapolated to unsurveyed areas, are accounted in JABBA model; some errors in the catch and abundance indices are revealed. The parameters of instantaneous rate of recruitment and initial depletion of population are determined. Overfishing is not detected yet in any fishing zone, but a negative trend of the biomass dynamics is noticed for the Western Bering Sea fishing zone since 2015 (if the stock estimations based on surveys are realistic). The decline is reasoned by implementation of too high target for exploitation rate of vulnerable biomass (φF = 0.10) that is higher than such target for other fishing zones (< 0.08 or even 0.01 for the stocks exploited with the total allowable catch limits). That’s why annual catches exceeded the surplus production in the Western Bering Sea fishing zone in 2012 and since 2015 to nowadays. The sum of median estimations for the maximum sustainable yields in all fishing zones is about 47.4 . 103 t that exceeds the values of total annual catch. The instantaneous rate of recruitment is almost equal in the neighboring fishing zones in the western Bering Sea and at East Kamchatka (0.086–0.085 by median, with 95 % credible intervals from 0.05 to 0.14) and is much higher at Kuril Islands with the maximum in the North-Kuril fishing zone. The latter case is possibly conditioned by partially external recruitment. Therefore, population structure of giant grenadier should be clarified for correct modeling of the recruitment; until then, the stocks assessments by fishing zones are available.

Importance of fish species in the bottom and near-bottoml biotopes of the Far-Eastern Seas and Pacific waters of Russia

Importance of fish species in the benthal ichthyocoenoses (up to depths of 2000 m) is discussed for the Russian waters in the Far-Eastern Seas and adjacent North-West Pacific on the data of bottom trawl surveys conducted by Pacific Fish. Res. Inst. (TINRO) in 1977–2010. The inverse Simpson index (or polydominance index) was chosen as a measure of dominance; Sorensen-Chekanovsky similarity index was used for comparative analysis of the dominance structure in ichthyocoenoses. The importance is determined for the top 20 species ranked by biomass (94.9 % of the total biomass of all demersal fish on the shelf and 95.8 % — at the continental slope, on average). Poor evenness under strong domination of 2–4 species is noted in the fish communities within the range of 0–2000 m. Walleye pollock Theragra chalcogramma dominate in all regions whereas the subdominants are pacific herring Clupea pallasii, pacific cod Gadus macrocephalus, atka mackerel Pleurogrammus monopterygius, or okhotsk atka mackerel P. azonus, depending on the region. The pollock domination is interrupted at the continental slope of the Bering Sea, where giant grenadier Albatrossia pectoralis dominate. The subdominants at the continental slope of all regions are greenland halibut Reinhardtius hippoglossoides matsuurae, popeye grenadier Coryphaenoides cinereus, pacific herring, pacific sleeper shark Somniosus pacificus, scale-eye plaice Acanthopsetta nadeshnyi, and blackfin flounder Glyptocephalus stelleri. Generalized graphs of the ichthyocoenoses similarity between the studied regions (Okhotsk Sea, Bering Sea, Japan Sea, and Pacific waters at Kamchatka and Kuril Islands) by species structure and composition of the dominant species are presented, separately for the shelf and continental slope.

The Influence of Transglutaminase on Minced Muscular Fish Tissue Structure Formation After the Application of Various Protein Substrates

This research aimed to examine the effect of a microbial transglutaminase preparation (Activa® GS, Ajinomoto Co., Inc, Japan) on the structure formation of the myofibrillar protein system of a deep-sea fish species – the giant grenadier – after the addition of various protein substrates. The low content of proteins and their low water-holding capacity in this fish, subjected to various processing methods, leads to significant losses in the initial mass and decreased gelation ability in the muscle tissue system. Various concentrations of transglutaminase were used but these did not ensure the restructuring of the initial muscle tissue of the grenadier. Additional protein substrates with different molecular weights and amino acid composition were added, including gelatin, milk casein, hydrolysates of the skin and milt of the fish, and whole bivalves, which were used to create a firm structure. It was shown that the introduction of gelatin and casein at a concentration of 5% led to the formation of a firm, thermostable structure under the action of the enzyme, while hydrolyzed proteins with low molecular weight at their various concentrations enhanced the expression of water and formation of the fluid consistency. The ability of gastrointestinal tract proteases (pepsin and trypsin) to digest did not depend on the formation of protein-to-protein cross-linking in these combined products. The influence on the growth of the Tetrahymena pyriformis ciliates test culture also showed the high degree of product availability. The technology of molded products based on fermented minced muscle tissue of grenadier with added casein, both in the form of semi-finished products and in the form of ready-to-eat products, was developed.
 Keywords: transglutaminase, muscle tissue, structure formation, deep-sea fish

Application of transglutaminase in moulded food processing from waterlogged fish raw materials

Application conditions of the ACTIVA® TG-TI transglutaminase combined with setting agents (gelatine and chitosans of various modifications) are substantiated for moulded food processing from waterlogged fish raw materials targeted by deep-water fishery, i.e. giant grenadier (Albatrossia pectoralis). It was shown that combining different setting agents ensures time reduction of gel formation with a minor change in their development and melting temperatures. Adding an enzyme preparation leads to the formation of thermostable gels with a 1.5-fold increased strength. When forming gels from the grenadier muscle tissue in the presence of setting agents of different concentrations, the quality of soluble muscle proteins reduces, most prominently with gelatine and chitosan ascorbate. Physicochemical parameters of the structured gels prepared from the muscle tissue of giant grenadier (moisture retention capacity, tensile strength, water activity) and their organoleptic profiles were measured. Based on the results, we have shown that adding 3% of gela-tine, 0.06% of high-molecular chitosan and 1% of transglutaminase may be employed for processing moulded fish products. The digestibility of the protein components in obtained samples did not depend on fermentation. The overall protein deposition was between 0.38 and 0.56% of the sample mass. The total biological value of samples ranged from 78 to 134% when studying their effect on the growth of T. pyriformis testing culture.

Raising the efficiency of fish farce production from under-used fish raw

We test the technology of producing fish farce from ground fish muscle of giant grenadier (Albatrossia pectoralis) by preliminary heat treatment and salt curing with simultaneous dewatering. We provide a scientific basis to the influence of length of heat treatment and size of grinding on viscosity and adhesiveness of the farce system made of Giant grenadier (Albatrossia pectoralis). We found out that length of treating chunks of 1-5 grams each with live steam at a temperature of (100±2)°C should not exceed 2-3 minutes, and this should improve functional and technological properties of fish farce. We studied the influence of preliminary salt curing and simultaneous draining of liquid fraction on adhesiveness and viscosity of fish muscle of giant grenadier (Albatrossia pectoralis) depending on a degree of grinding. We found out that the reasonable time for salt curing of ground fish muscle of giant grenadier (Albatrossia pectoralis) and simultaneous draining for a sample with chunks of 1-5 grams each is a period of 15-20 minutes at room temperature (20±2)°C, during which the rheological properties reach their maximum. Based on obtained results, it seems perspective to produce fish farce from Giant grenadier (Albatrossia pectoralis) by live steam blanching and salt curing with simultaneous draining, which methods make it possible to produce farce systems with improved functional and technological properties and structure.

A resource saving technology for industrial processing of deep-sea and demersal fishes

This article shows the results of testing the technology of producing combined fish farce from deep-sea and demersal fishes. The object of our research is frozen fish, such as Giant grenadier (Albatrossia pectoralis), Alaska plaice (Pleuronectes quadritubercula-tus), Pacific halibut (Hippoglossus stenolepis) and Pacific ocean perch (Sebastes alutus). We found out that a combination of Giant grenadier (Albatrossia pectoralis) and demersal fishes, such as Alaska plaice (Pleuronectes quadrituberculatus), Pacific halibut (Hippoglossus stenolepis) and Pacific ocean perch (Sebastes alutus) in the proportion of 50:50 and a certain salt curing method make it possible to produce high-quality farce systems. We provide a scientific basis for the certain technological parameters defining the formation process of farce system texture depending on the quantity of sodium chloride, temperature of salt curing and length of curing. We found out that sodium chloride at a rate of 1.5-2.0% increases rheological properties of combined fish farce. We outlined conditions and parameters of technological treatment affecting the quality characteristics of ground fish muscle of giant grenadier (Albatrossia pectoralis) with preliminary salt curing. We found out that the highest values of adhesiveness, viscosity, water retention capacity and yield strength belong to experimental samples with 1.5-2.0% of sodium chloride to the raw mass with the temperature of curing plus 20±2°C and reasonable curing time of about 15-20 minutes. Based on the data obtained, it seems promising to produce combined fish farce from deep-sea and demersal fishes, since this method makes it possible to improve their functional and technological properties and to increase consumption of deep-sea and demersal fishes for food.

Научные аспекты эффективности использования макруруса, ставриды исардинеллы втехнологии пищевых продуктов

An increase in the Russian catch of aquatic biological resources may be provided by the underutilized resources of the World Ocean, which include such fish species as, horse mackerel, round sardinella and giant grenadier. Studies were carried out to study the size-mass composition of horse mackerel, round sardinella and giant grenadier, which showed that fillet yield when cutting giant grenadier was 61.2%, large horse mackerel 63,3%, shallow horse mackerel 47,9%, and round sardinella 54.8%. Based on the data on the fractional composition of proteins and the structural and mechanical properties of muscle tissue, the expediency of manufacturing various molded products and minced products such as sausages and sausages from horse horse mackerel and round sardinella, and dietary pasty food products from giant grenadier was established. Rational parameters of muscle tissue grinding of horse mackerel, round sardinella (2 min at 3000 rpm) and giant grenadier (6 min at 3000 rpm) have been scientifically substantiated. It has been established that the creation of stable protein-fat emulsions based on minced giant grenadier, horse mackerel and round sardinella is possible when the ratio of protein, fat and water is 1: 2.1 v 3.5: 9 for giant grenadier; 1: 0.3: <13.2 for horse mackerel and round sardinella.

ОБОСНОВАНИЕ ПАРАМЕТРОВ СУШКИ МАКРУРУСА МАЛОГЛАЗОГО (ALBATROSSIA PECTORALIS) В ПРОЦЕССЕ ПРОИЗВОДСТВА ИЗ НЕГО СУШЕНО-ВЯЛЕНОЙ ПРОДУКЦИИ

Giant grenadier (Albatrossia pectoralis) is an underused commercial object, and improvement of its pro-cessing technology presents an urgent scientific and industrial problem. The solution to this problem, to a certain extent, is associated with the development of an effective technology for production of dried-cured products from this raw material. The study results of drying giant grenadier dynamics under various conditions, degree of proteins denaturation, organoleptic characteristics of dried products proved the rational modes for its processing in convective dryers. A three-stage drying was used at a temperature of 20ºC in the production of dried fillets, the duration of the first stage was 6 hours and leveling for 4 hours, the second stage was 6 hours and leveling for 4 hours and, finally, drying for 4 hours. During production of dried-cured products in the form of flakes, the fillet (i.e. decapitated fish) was divided into pieces (flakes) after the se-cond drying. Then they were soaked in a flavored filling and dried for 4 hours.

Development of pasty food products based on muscle tissues of giant grenadier and horse mackerel

Malnutrition problems are acute in all countries and are common to all socio-economic groups. Improper nutrition is the cause of cardiovascular diseases, diabetes, gout, osteoporosis, obesity and other non-infectious (nutritional) diseases. Aquatic bioresources, especially underutilized fishing objects, are sources of a number of irreplaceable nutrients, which makes them useful for creating functional and specialized foods. So stuffing on the basis of muscle tissue makrouruz and mackerel is a promising raw material for the production of pasty food products. Based on regulatory documents and methodological recommendations in the field of specialized, functional and therapeutic nutrition, a scientifically-based selection of functional food ingredients was carried out to create a pasty food product — pate. As a result of the simulation, seven formulations of pâtés were developed on the basis of the minced meat of makruirs and scad. Developed pates for a number of indicators correspond to the products recommended as therapeutic nutrition in hospitals.

Biochemical Factors Affecting the Quality of Products and the Technology of Processing Deep-Sea Fish, the Giant Grenadier Albatrossia pectoralis

The composition of muscle tissues of a deep-sea species, the giant grenadier (Albatrossia pectoralis), and a mesopelagic species, the Alaska pollock (Theragra chalcogramma), are compared. Grenadier is proved to have a higher moisture content (91.7%) and lower protein (7.4%) and lipid (0.3%) contents. The factors responsible for the softening and moisture separation during processing of grenadier are identified. Contents of some fractions of non-protein nitrogenous components, including trimethylamine oxide (TMAO) and free amino acids, are clarified. The proportion of the main myofibrillar proteins myosin and actin, which is considered as an indicator of efficiency of structure formation in fish muscle tissue during processing, is almost 20% lower in giant grenadier than in pollock. The effects of endogenous protease, Ca2+-ATPase and transglutaminase on the processes of autolysis, denaturation, and possibility of myofibrillar proteins cross-linking were also studied. The proposed technology of getting a nutritionally balanced, gel-like, ready-to-use foodstuff from grenadier fillet includes its enrichment with pollock muscle tissue and supplementing with a binary structure-forming agent containing collagen and chitosan. Nutritional value of the products is assessed by the method of biological assay and by determining the denaturation changes of myofibrillar proteins. The modes of fine mincing and thermal processing, as well as the shelf-life of the finished product are justified. The developed technology of producing a ready-to-eat food from giant grenadier will allow a more efficient use of this underutilized resource.

High resolution melting (HRM) analysis of a 12S rRNA mini barcode as a novel approach for codfish species authentication in processed fish products

Codfish is an essential part of the marine fishery resources, and contains several commercially important species, including Gadus species (G. morhua, G. macrocephalus, and G. chalcogrammus), and other five Gadiformes species, including Pollachius virens, Melanogrammus aeglefinus, Merluccius merluccius, Merluccius australis and Albatrossia pectoralis. According to our previous studies, Gadus species represents the most frequently used Gadiformes species for codfish products, with other five Gadiformes species also occasionally found. However, due to the legislative shortcomings, there is still not a harmonization around the definition of codfish in China, leading to great chaos. To help prevent this episode, the present study aimed to develop a one-tube fast method for codfish species identification, with particular attention to differentiate Gadus species, and the other five Gadiformes species, using the high resolution melting (HRM) analysis of a 12S rRNA mini barcode. The specificity of the newly designed primers was successfully confirmed for the eight common Gadiformes species. The novel HRM assay allowed the full discrimination between Gadus species and the other five Gadiformes species. 19 commercial codfish products were included in the Gadus cluster, cross-confirmed by the real-time PCR and DNA barcoding. The identification of less valuable U. japonicas is essentially a consumer fraud, while great health concern could also be highlighted by the identified Lagocephalus species. The established HRM of a 12S rRNA mini barcode method in the present study allows a fast and accurate identification of codfish species in processed fish products.

Оценка рыбного сырья как способ повышения информативности его характеристик

Introduction. The research features a detailed sensory evaluation of mass fishing objects belonging to different families, namely: the Macrouridae represented by the giant grenadier (Albatrossia pectoralis), the Herrings represented by the Pacific herring (Clupea pallasii), and the Salmons represented by the Keta salmon (Oncorhynchus keta). The research objective was to study the possibility of increasing the information content of the verbal description of fish raw materials in combination with a quantitative assessment of individual sensory indicators.&#x0D; Research objects and methods. The paper introduces the concept of detailed verbal description of group parameters of raw and heattreated muscle tissue. The description can increase the information capacity of sensory studies. The concept of extended description of fish raw material was added to the main sensory properties that describe color, smell, taste, and consistency. They include data on the properties of local areas with subcutaneous layer, dark muscles, fat layers, etc. Such a detailed verbal description gives an in-depth view of the sensory properties, which is part of general information on the functional and technological properties of the fish and a key factor in designing new developed products. To improve the objectivity of sensory research, the authors employed the method of quantitative evaluation.&#x0D; Results and discussion. The results were summed up as data on the significance coefficients established by experts, ranked, and expressed as a percentage. The significance coefficient is a method of quantitative regulation of the share of each sensory indicator in the general sensory evaluation. The research showed that the greater the number of group sensory indicators that characterize the object, the smaller and more similar their coefficients of significance, which dramatically reduces application opportunities. Therefore, significance coefficient proved a convenient means of measurement and visual presentation. However, the research was limited by the experimental conditions. &#x0D; Conclusion. The study of the fish raw materials established, identified, and described individual sensory indicators that involved about twenty lexical units for raw material and thirty units for heat-treated muscle tissue. The individual sensory indicators characterized color, smell, and taste. They differed in the presence of several degrees of gradation and fit into a vertical three-level (sometimes two-level) classification. Group touch indicator of the consistency describes mostly single-level unit indicators with 4–6 lexical units. As a result, the detailed description of sensory properties of fish raw materials included 2–3 times more lexical units compared to the traditional description of fish raw materials in the special reference literature.

Development of a rapid method for codfish identification in processed fish products based on SYBR Green real‐time PCR

SummaryUsing species outside the order Gadiformes to prepare codfish products has been widely revealed as a new type of fraud in China, highlighting the necessity to establish proper methods for codfish species identification. This work aimed to develop a new SYBR Green real‐time PCR assay for the detection of codfish ingredient (mainly the eight Gadiformes species, Gadus morhua, Gadus macrocephalus, Theragra chalcogramma, Pollachius virens, Melanogrammus aeglefinus, Merluccius merluccius, Merluccius australis and Albatrossia pectoralis) in processed fish products based on mitochondrial 12S rRNA gene. Results highlighted the positive Cq (cycle quantification value, average value 19.18 ± 1.49) only from the eight Gadiformes species, with no fluorescent signal (Cq &gt; 32) for the other sixty‐seven non‐Gadiformes species. The absolute limit of detection was 0.048 ng genomic DNA. Methodology validation succeeded in twenty‐six commercial products. These results demonstrated that the newly developed method is suitable for the identification of codfish ingredient in processed fish products.

БИОТЕСТИРОВАНИЕ РЫБНОЙ КУЛИНАРНОЙ ПРОДУКЦИИ С ИСПОЛЬЗОВАНИЕМ TETRAHYMENA PYRIFORMIS

The article presents the results of biotesting food protein gels and ready-to-eat gel-based fish products. Axenic culture of ciliates Tetrahymena pyriformis was used as an indicator organism, which are known to have similar metabolic processes with cells of higher organisms. The ability of unicells to use intact proteins as a nutrient substrate determines their use in assessing the biological value of food. In the course of research, using a test-organism T. pyriformis , the rational temperature of heat treatment of food protein gel was equal to 85°C. Such temperature provides high rates of the ciliates population in the cultivating environment, the number of cells in which was counted and amounted to 2.3 × 106 cells/ml. In addition, the finished product has a high bioavailability ratio of 160% relative to the non-thermoprocessed product (i.e., raw). Biotesting ready-to-eat fish products enriched with protein from different fish in the Pacific basin made it possible to carry out a comparative characteristic of their biological value. It was determined that ready-to-eat fish products from giant grenadier, in which pollock served as enricher, have the highest index of the relative biological value - 101.4%, which is confirmed by studying the protein content of the products. At the same time, gels from the muscular tissue of giant grenadier without protein enrichers possess high indices of bioavailability and effectiveness of the protein when compared with product samples that contain protein enricher. However, this phenomenon causes the rapid depletion of the nutrient medium after 48 hours and further death of the T. pyriformis population. Thus, biotesting using the simplest allows for a comparative assessment of ready-to-eat fish product quality by simply counting the number of ciliates by experience in culture media. A graphical analysis of the data obtained throughout the life cycle of a T. pyriformis population allows to quickly and accurately assess the viability of ciliates, the degree of assimilation of the nutrient substrate, and draw conclusions about the biological value of the product.

LONG-TERM AVERAGE BIOMASS AND DOMINANT FISH SPECIES IN THE BOTTOM BIOTOPES OF THE OKHOTSK SEA. PART 2. COMPOSITION AND QUANTITATIVE RATIO OF SPECIES AT THE CONTINENTAL SLOPE IN DIFFERENT AREAS OF THE SEA

Demersal fish biomass is quantitatively evaluated in the bottom biotopes at the depths to 2000 m at the continental slope of the Okhotsk Sea on the data of 2,545 trawl catches obtained in 1977–2010. The total long-term average biomass is estimated as 3695.9 . 103 t, including 31.6 % of walleye pollock, 19.5 % of giant grenadier, and 13.8 % of greenland halibut (2400.9 . 103 t without pollock). The average density of fish concentration is 3.2 t/km2 without pollock; it is rather uniform by depth: from 2.6 t/km2 for 200–300 m to 3.7 t/km2 for 700–1000 m.

Otolith shape variability and associated body growth differences in giant grenadier, Albatrossia pectoralis.

Fish stocks can be defined by differences in their distribution, life history, and genetics. Managing fish based on stock structure is integral to successful management of a species because fishing may affect stocks disproportionately. Genetic and environmental differences can affect the shape and growth of otoliths and these differences may be indicative of stock structure. To investigate the potential for speciation or stock structure in giant grenadier, Albatrossia pectoralis, we quantified the shape of female giant grenadier otoliths and compared body growth rates for fish with three otolith shapes; shape types were classified visually by an experienced giant grenadier age reader, and were not defined by known distribution or life history differences. We found extreme variation in otolith shape among individuals; however, the shapes were a gradation and not clearly defined into three groups. The two more extreme shapes, visually defined as “hatchet” and “comb”, were discernable based on principal component analyses of elliptical Fourier descriptors, and the “mixed” shape overlapped both of the extreme shapes. Fish with hatchet-shaped otoliths grew faster than fish with comb-shaped otoliths. A genetic test (cytochrome c oxidase 1 used by the Fish Barcode of Life Initiative) showed almost no variability among samples, indicating that the samples were all from one species. The lack of young specimens makes it difficult to link otolith shape and growth difference to life history. In addition, shape could not be correlated with adult movement patterns because giant grenadiers experience 100% mortality after capture and, therefore, cannot be tagged and released. Despite these limitations, the link between body growth and otolith shape indicates measurable differences that deserve more study.

Biological features of the common fish species in Olyutorsky-Navarin region and the adjacent waters of the Bering Sea: 2. Families Macrouridae, Clupeidae, and Osmeridae

Biological features of the four common fish species, giant grenadier Albatrossia pectoralis (Macrouridae), Pacific herring Clupea pallasii (Clupeidae), Pacific rainbow smelt Osmerus mordax dentex, and Pacific capelin Mallotus villosus catervarius (Osmeridae), were studied under the 20-year dataset (1995−2015). These species inhabit the northwestern Bering Sea in the summer–autumn period and form the schoolings in the Olyutorsky-Navarin region. The size–age parameters of the fish caught by different sampling gear, as well as the peculiarities of the body length and body weight dynamics, spawning periods, spawning range, and conditions, were analyzed. The largest specimens of giant grenadier, Pacific herring, and Pacific rainbow smelt were observed in the catches performed by the bottom setline and the gill nets; the smallest fish were found in the trawl catches. The body length and body weight of Pacific herring were larger in the pelagic trawls compared to the bottom trawls; an opposite pattern was observed for the Pacific capelin. The abundant year-class in the species with short life cycle (capelin and herring) is well tracked on the longterm plots of the fish body size; this is accompanied by the decrease of their biological parameters. Herring stock covers large growing grounds; smaller body size was observed for the herring grazing in the coastal waters; young specimens dominate here.

Depth as a driver of evolution in the deep sea: Insights from grenadiers (Gadiformes: Macrouridae) of the genus Coryphaenoides

Here we consider the role of depth as a driver of evolution in a genus of deep-sea fishes. We provide a phylogeny for the genus Coryphaenoides (Gadiformes: Macrouridae) that represents the breadth of habitat use and distributions for these species. In our consensus phylogeny species found at abyssal depths (>4000m) form a well-supported lineage, which interestingly also includes two non-abyssal species, C. striaturus and C. murrayi, diverging from the basal node of that lineage. Biogeographic analyses suggest the genus may have originated in the Southern and Pacific Oceans where contemporary species diversity is highest. The abyssal lineage seems to have arisen secondarily and likely originated in the Southern/Pacific Oceans but diversification of this lineage occurred in the Northern Atlantic Ocean. All abyssal species are found in the North Atlantic with the exception of C. yaquinae in the North Pacific and C. filicauda in the Southern Ocean. Abyssal species tend to have broad depth ranges and wide distributions, indicating that the stability of the deep oceans and the ability to live across wide depths may promote population connectivity and facilitate large ranges. We also confirm that morphologically defined subgenera do not agree with our phylogeny and that the Giant grenadier (formerly Albatrossia pectoralis) belongs to Coryphaenoides, indicating that a taxonomic revision of the genus is needed. We discuss the implications of our findings for understanding the radiation and diversification of this genus, and the likely role of adaptation to the abyss.

New target fisheries lead to spatially variable food web effects in an ecosystem model of the California Current

Growing human populations put increasing demands on marine ecosystems. Studies have demonstrated the importance of large biomass forage groups in model food webs, but small biomass contributors are often overlooked. Here, we predict the ecosystem effects of three potential future fisheries targeting functional groups that make up only a small proportion of total ecosystem biomass using the California Current Atlantis Model: deep demersal fish such as grenadier (Albatrossia pectoralis and Coryphaenoides acrolepis), nearshore fish such as white croaker (Genyonemus lineatus), and shortbelly rockfish (Sebastes jordani). Using a spatially explicit ecosystem model, we explored individual fishing scenarios for these groups that resulted in abundance levels of 75, 40, 25, and 0 percent of the status quo fishing scenario and a combined fishing scenario simultaneously targeting all three groups. We evaluated the effects on coast-wide biomass and describe variation in affected groups by region. Results indicate that developing fisheries on the proposed targets would have small coast-wide effects on other species. However, effects varied significantly within the ecosystem, with higher impacts concentrated in the central California region of the model. Effects of fishing all three groups simultaneously were additive in some cases coastwide, but were not additive at the regional scale. This work provides a framework for evaluating effects of new fisheries and suggests that regional effects should be evaluated within a larger management context.