Ocean Perch Research Articles

Exploring food-specific IgG responses in pediatric allergic disorders: A retrospective cross-sectional study

Background: The role of immunoglobulin G (IgG) responses to food as potential triggering factors in allergic disorders continues to be debatable, and is not endorsed by most allergy societies. Objective: To explore the prevalence of specific IgG immune responses to common foods in pediatric allergic disorders and any potential relationship between them. Methods: A retrospective study was conducted on children and adolescents diagnosed with allergic disorders at the Ekthar Clinic in Jeddah City. Food-specific IgG (FS-IgG) antibody test results were collected from their medical records. Results: Seventy-five children with a mean age of 8.5 years (SD = 5.3) were included. The overall allergic diagnosis determined atopic dermatitis as the most common (57.3%, 43 participants), followed by food allergy and allergic rhinitis (each 40%, 30 participants), and bronchial asthma (29.3%, 22 participants). Food-specific IgG levels were elevated in all participants. The foods with the highest levels of FS-IgG were dairy products (88%: cow’s milk [86.6%], sour milk [81.3%], sheep’s milk [74.7%], cheese [72%], and goat’s milk [70.7%]), followed by gluten-containing products (81.3%: wheat [70.7%], gluten [69.3%], and spelt [66.6%]), and eggs (66.6%). Significant correlations (P < 0.05) were found between atopic dermatitis and several foods; chronic urticaria and chicken and lamb; asthma and ocean perch; allergic rhinitis and rennet cheese; and allergic conjunctivitis and potato, pollock, and lamb. Conclusion: Among pediatric allergic disorders, dairy, gluten, and eggs were the most detected foods in FS-IgG tests, with some notable correlations with other foods. FS-IgG testing may help identify potential triggers in refractory allergic disorders.

Quality changes in cod (Gadus morhua) and redfish (Sebastes marinus) loins and tails during frozen storage

The muscle structure and composition may vary along the different portions of fish fillets, which can complicate the quality and storage stability of products. Loins and tails from Atlantic cod (Gadus morhua) and redfish (Sebastes marinus) fillets were therefore stored at −25 °C up to 16 months and 20 months, respectively, to investigate the quality changes influenced by the duration of frozen storage within the fillet portions. Throughout the storage period, the loss of total sulfhydryl groups correlated with increased disulfide bonds, indicating partial oxidative protein degradation. This may be linked with protein denaturation as evidenced by the decrease of soluble proteins, as well as decreased water holding capacity and increased thawing drip loss and cooking loss. The results from the cod samples reveal that stronger degradation changes occurred in the tail. The loin, therefore, had more storage stability as well as higher nutritional value. However, other quality attributes were similar between the two portions in the redfish fillets. Higher free fatty acid (FFA) values, lower soluble protein contents, and higher disulfide bond contents were obtained in the cod samples compared to the redfish samples at the same storage time, indicating that lipid hydrolysis and protein degradation effects were stronger in the cod (lean fish) compared to redfish (medium fat species).

Fishery and notes on the biology of Pacific ocean perch Sebastes alutus (Sebastidae) off the Commander Islands

The fishery and some aspects of the biology of the Pacific ocean perch Sebastes alutus off the Commander Islands. It has been established that the harvest of this species is episodic in nature, is not subject to seasonal dynamics and is carried out in a local area located west of the Bering Island. The contribution of this water area to the total catch of rockfishes in the Petropavlovsk-Commander subzone in 2001–2022 did not exceed 26.5%. Near the Commander Islands, S. alutus was observed at depths of 138–370 m at a water temperature near-bottom of 3.1–3.9°C, and in catches it was represented by individuals 17–45 cm length. Presumably the formation of accumulations in the upper part of the continental slope to the west of the Bering Island is due to the presence of an anticyclonic circulation, which contributes to the formation of high concentrations of zooplankton as the main food source and favorable conditions for the development of spawned larvae.

Contribution of offshore platforms and surrounding habitats to fish production in the Bass Strait, south-east Australia

Information on the contribution of offshore oil and gas (O&G) platforms to fish productivity is required to contribute to the decision-making process to remove, partially remove, or retain these structures during decommissioning after petroleum production ceases. The present study assesses the biomass and fish production of one common and abundant fish species (Caesioperca lepidoptera – butterfly perch) and two commercially fished species (Helicolenus percoides – reef ocean perch; Nemadactylus macropterus – jackass morwong) on eight O&G platforms and in surrounding natural habitats in the Bass Strait, south-east Australia, where options for decommissioning are being assessed. High-definition stereo-video imagery was collected by remotely operated vehicle (ROV) from eight platform facilities, their immediate benthic surrounds, reference areas reflective of the likely pre-installation seabed state (sand-dominated) and a nearby natural ‘reef’ area referred to as south-east reef (some limestone foundation). The biomass of all three species was low in the benthic surrounds of platforms, at reference locations and at south-east reef where minimal cover by benthic organisms was recorded and, as such, there was little to no fish production for the three study species in these areas. We observed a total fish biomass of 2.85 tonnes across the eight platforms for the three fish species surveyed, with high variability across platforms. Total production (P) across all platforms was estimated at 1244 kg/year for the three species, with a mean fish production density of 82 g/m2/year. Approximately 79% of total production is considered ‘new’ production (984 kg/year i.e., the production attributed to the presence of the platforms; with a mean production density of 64 g/m2/year). The remaining 21% could be retained or redistributed into the surrounding area if platforms were removed. C. lepidoptera accounted for the majority (90%) of biomass and of total production for all three species across all locations surveyed. Despite only accounting for a small proportion of platform surface area, the bottom 5 m sections of platforms had 41% of the total biomass observed and accounted for 46% of total production of these three study species. Production measures for platforms surveyed here are relatively high compared to other artificial reefs and habitats around the world. Total removal of these platforms will likely result in a reduction of fish biomass and fish productivity (incl. several fishery species) in the immediate vicinity.

The Evolution of Redfishes of the Genus <i>Sebastes</i> (Perciformes: Sebastidae) of the Atlantic and the Arctic Oceans: Budding Speciation in the Species Flock

The evolutionary history of North Atlantic Sebastes redfishes was reconstructed as a result of studying the mitochondrial DNA D-loop sequences of Sebastes redfishes inhabiting the North Atlantic and the Arctic Oceans. It was shown, that speciation of these redfishes occurred in several stages. During the first stage, the ancestor of Norway redfish (S. viviparus) diverged from the common ancestor species in the process of allopatric speciation. Ancestor of Acadian redfish (S. fasciatus) diverged from the common ancestor as it evolved. Budding speciation in the species that would later evolve into golden redfish (S. norvegicus) resulted in emergence of beaked redfish (S. mentella). Paleoclimatic events seem to have played the key role in species divergence as they caused habitat fragmentation allowing the isolated groups to become genetically distinct in the meantime. The conducted analysis of Sebastes redfishes speciation brings into question the generality of widely accepted views on fish sympatric speciation. It also serves as an argument against the molecular clock hypothesis.

The design of a camera-based fisheries-independent survey for untrawlable habitat in the Gulf of Alaska

Biomass and size composition estimates from the fishery independent biennial Alaska Fisheries Science Center Resource Assessment and Conservation Engineering Division’s Groundfish Assessment Program Gulf of Alaska bottom trawl survey are an integral component of stock assessments and management of fishes in the region. A substantial proportion of the seafloor in the Gulf of Alaska survey area consists of rocky, high-relief habitat that is not accessible to trawl survey gear and is important habitat for many harvested fish species, especially rockfishes (Sebastes spp.). Survey estimates of groundfish abundance from trawlable grounds are expanded across the entire region. Therefore, survey abundance estimates could potentially be biased as a result of sampling that does not spatially represent all of the available habitat circumscribed by the Gulf of Alaska study area. Mapping the extent of the untrawlable habitat is a critical step toward understanding the scale of these potential biases and would benefit the design of a future untrawlable habitat survey. Several previous efforts have provided trawlability maps for part or all of the Gulf of Alaska based on different data inputs. In the present work, we compile two previously published untrawlable habitat maps with three other relevant data sources to create a new untrawlable habitat map, and use this map in conjunction with density estimates from existing underwater camera studies to investigate the feasibility of an untrawlable habitat rockfish survey in the Gulf of Alaska. An analysis of 1 km2 grids sampled more than once with a lowered camera system suggested that a single-stage sampling design (one camera transect per grid) would be most effective. Post-stratification analysis showed that either a simple depth stratification or stratification based on species distribution models provided lower coefficient of variation (CV) values at a given sample size compared to random sampling. Furthermore, a target CV of 25 % could be reached for a camera survey of dusky rockfish, northern rockfish, or Pacific ocean perch with less than 200 lowered camera transects if a stratification scheme based on species distribution models was used.

No effects of ground-gear diameter on the performance of a south-eastern Australian fish trawl

As part of attempts at improving the selectivity of south-eastern Australian fish trawls, the effects of ground-gear disc diameter on trawl engineering and catching performances were investigated. Three conventional disc diameters (100 mm or 4 in., 178 mm or 7 in. and 254 mm or 10 in.) at the centre third of the ground gear were alternated during 12 days of conventional fishing. There were no significant effects of ground-gear configuration on otter-board spread or the headline height of the trawl. Rather, significant influences were limited to depth affecting positive and negative relationships with otter-board spread and headline height, and speed over the ground evoking a positive effect on otter-board spread. Catches of four retained species (bigeye ocean perch, Helicolenus barathri, pink ling, Genypterus blacodes, ocean leather jacket, Nelusetta ayraud, and tiger flathead, Platycephalus richardsoni) and two discards (smooth whiptail, Malacocephalus laevis and falseband whiptail, Coelorinchus maurofasciatus) and the sizes of three of these species, were not significantly different among ground gears. The results imply minimal benefit in varying conventional ground-gear configurations for reducing unwanted catches.

Sensory Properties and Chemical Composition of Fish Solubles Obtained from Upcycling of Fish Filleting Side Streams

ABSTRACT The whitefish processing industry generates large amounts of food-grade side streams consisting of trimmings, head-backbone-skin (HBS), and viscera. Several factory fishing vessels have fishmeal plants to utilize the residues after onboard processing of the fish, however, at present, the protein-rich solubles is discarded. In this study, fish solubles based on side streams from cod, saithe, haddock, and golden redfish were produced based on cooking, mechanical dewatering, centrifugation, and membrane filtration. All products had high flavor intensity, and only minor differences between fish species on sensory attributes were observed, suggesting a potential application as broth and flavor enhancer.

Incorporating non-stationary spatial variability into dynamic species distribution models

Abstract Ecologists and fisheries scientists are faced with forecasting the ecological responses of non-stationary processes resulting from climate change and other drivers. While much is known about temporal change, and resulting responses vis-à-vis species distributional shifts, less is known about how spatial variability in population structure changes through time in response to temporal trends in drivers. A population experiencing decreasing spatial variability would be expected to be more evenly spatially distributed over time, and an increasing trend would correspond to greater extremes or patchiness. We implement a new approach for modelling this spatiotemporal variability in the R package sdmTMB. As a real-world application, we focus on a long-term groundfish monitoring dataset, from the west coast of the USA. Focusing on the 36 species with the highest population densities, we compare our model with dynamic spatiotemporal variance to a model with constant spatiotemporal variance. Of the 36 species examined, 13 had evidence to support increasing patchiness, including darkblotched rockfish, lingcod, and petrale sole. Species appearing to be more uniformly spatially distributed over time included: Dover sole, Pacific ocean perch, and Dungeness crab. Letting spatiotemporal variation change through time generally results in small differences in population trend estimates, but larger estimated differences in precision.

The estimated impact of changes to otolith field-sampling and ageing effort on stock assessment inputs, outputs, and catch advice

Generating accurate data for stock assessments is resource-demanding, necessitating periodic evaluation of survey sampling designs and potential impacts on stock assessments. We developed a framework for bootstrapped resampling of survey age data and calculation of input sample sizes as a function of among-bootstrap variance in age compositions. Data from this bootstrap estimator were then used to evaluate the influence of alternative sampling rates and methods on uncertainty in estimates of the overfishing limit (OFL) calculated using stock assessment models. For dusky rockfish ( Sebastes variabilis) and Pacific ocean perch ( Sebastes alutus), a 10% decrease in the number of tows sampled upon led to a predicted 5%–6% increase in the CV of OFL (log–log slope = −0.576 to −0.486), which was greater than the 0%–2% increase from a 10% decrease in otoliths-per-tow (log–log slope = −0.238 to −0.029). Application of this approach across all stocks monitored in the survey of interest is required to identify which stocks ( i) benefit the most from increased sampling of ageing structures or ( ii) cost the least in terms of OFL uncertainty owing to reduced sampling.

Habitat value of subsea wells and pipelines for fishery target species in Australia

Subsea pipelines and wells installed to support the oil and gas industry represent some of the most extensive and numerous anthropogenic structures throughout global marine ecosystems. There remains a paucity of information on the habitat value of these structures for fishery target species and, as a result, little understanding of how decommissioning should be conducted to minimise impacts to populations of these economically and socially important species. We assess the diversity and abundance of species that are targets of recreational and commercial fisheries on 33 subsea wells and 17 pipelines across the tropical northwest and temperate southeast marine regions of Australia. We examine relationships between fish identity and abundance and a range of environmental (e.g., depth, location), infrastructure-specific (e.g., pipeline position, diameter, age, length of pipeline, height of well, position on well), and biological (% cover of epibiota) variables using video filmed by remotely operated vehicles during their routine offshore inspection and maintenance campaigns. A total of 100 fishery target species were observed across subsea well and pipeline infrastructure, 56 species uniquely observed on pipelines and nine unique to wells. The families Lutjanidae (snapper), Serranidae (rock cods, groupers, perch), and Carangidae (trevallies) were most common and abundant on both wells and pipelines. In the northwest, lutjanids were most abundant around the base of wells, in shallow depths, on shorter wells, and where pipelines spanned the seafloor. A greater number of fishery target species and abundance of ocean perch (Helicolenus spp.) were also associated with pipelines that spanned the seafloor in temperate southeast Australia. The combined biomass of three species of snapper on wells in the northwest was 1,270 kg, with production levels for these species on each well estimated to be 105.2 g m2 year-1. The present study serves as an important reference point for informing decommissioning decisions for pipeline and well infrastructure and demonstrates the utility of industry-held data for science. We suggest that key predictor variables identified here be incorporated into comprehensive before-after-control-impact scientific studies for specific fields/assets to enable the prediction of potential impacts of decommissioning scenarios on marine communities present and quantification of such impacts after the decommissioning activity has occurred.

Sustainable fisheries: Towards operationalization of decision making accounting for biodiversity

Overexploitation of biotic resources constitutes a major threat on marine biodiversity while demand for seafood will rise in the next decades. Application of Life Cycle Assessment to marine ecosystems needs further focus. This study applies two existing methods (Langlois et al., 2014 and Emanuelsson et al., 2014) of fishing impact assessment on biodiversity to 125 common fish stocks fished in the 14 marine areas drawn by FAO and proposes operational guidelines for sustainable production and efficient conservation policies. We show that unsustainable fishing is responsible for a loss of up to 30 times the potential yield of major fish stocks such as Atlantic cod, red snapper and bluefin tuna. We identify depleted fish stocks for which biomass is up to 15 times lower than it should be (yellownose skate fished in South America) and stocks facing fishing mortality up to 1.9 × 107 times higher than required to allow sustainable recovery (Pacific Ocean perch fished on the US West Coast). Regarding intrinsic biodiversity, our study shows that we are not able to understand the consequences of overfishing through a cause-effect chain due to lack of science knowledge. However, we display how to limit the impacts on biodiversity by using complementary indicators at species and ecosystem level. The complexity of marine ecosystems and the remaining limits of studied methods are discussed, showing the compelling need for further data collection and analysis, and opening ways for targeted research.

Synthesizing integrated ecosystem research to create informed stock-specific indicators for next generation stock assessments

Over the past two decades, numerous ecosystem surveys and process studies have emerged to monitor and assess the large marine ecosystems of Alaska. Several regional collaborative integrated ecosystem research projects (IERPs) were conducted to gain understanding of fish population fluctuations in relation to the surrounding environment. The Gulf of Alaska (GOA) IERP is one example of such an effort. Products of this program include a suite of in situ observations from fully integrated ecosystem surveys, laboratory experiments of physical thresholds for fish condition, and high-resolution oceanographic, planktonic, and habitat distribution models. When coupled, the synthesis products of this program can be utilized to understand system connectivity and highlight the primary ecosystem drivers of the GOA. Much of this information was included in annual GOA ecosystem status reports through individual indicator contributions. However, assimilation of these data into single-species stock assessments has remained limited. We provide a clear and direct avenue for including the products of these IERPs through the new ecosystem and socioeconomic profile (ESP) framework that identifies mechanistic relationships and tests ecosystem linkages within the stock assessment process. We present a case study using a data synthesis of the five commercially and ecologically valuable focal species of the GOAIERP (sablefish, pollock, Pacific cod, arrowtooth flounder, and Pacific ocean perch). Information was organized along the categories of distribution, phenology, and condition by life history stage to develop life history narratives for each species. These narratives identified critical ecosystem processes that could impact survival of each species. We then used habitat distribution models, seasonal phenology, and energy allocation strategies to sequentially reduce two gridded temperature datasets to reflect the life experience of the stock. This method essentially aligns ecosystem information at a spatial and temporal scale relevant to a stock and creates informed indicators that could then be related to a stock assessment parameter of interest, such as recruitment. Informed temperature indicators differed in magnitude and variability when compared to non-informed indicators and demonstrating species and stage-specific thermal preferences. The difference between the informed indicators and the non-informed indicators can also highlight thresholds and trends in habitat preference that could be further investigated with targeted process studies or laboratory experiments. The coordinated nature of the IERP allowed for the creation of these informed indicators that would not be possible with the results of any one process study. Both the stock-specific narratives and the informed indicators can be included into the ESPs for further monitoring and development. This integration ensures that the identified ecosystem linkages are evaluated concurrently with the stock assessment and ultimately transferred to fishery managers in an efficient and effective format for informing management decisions.

Cautious considerations for using multiple covariate distance sampling and seafloor terrain for improved estimates of rockfish density

Distance sampling is one of the most widely used methods for adjusting fish counts for detectability, which allows the estimation of absolute density. Further, abundance can be estimated spatially beyond the transect width with density surface models. The present study used a density surface modelling approach with survey data from line transects and terrain metrics from multibeam acoustic bathymetry data, integrated with a Geographic Information System, to estimate the population density of Pacific Ocean perchSebastes alutus(POP) within 6 sampling areas in the Gulf of Alaska (GOA) at 2 sampling scales: local and landscape. For adult POP, the final density model included depth as a significant predictor for density estimation at both the local and landscape scale. Additional factors included sponge coverage (local scale), aspect eastness and seafloor slope (landscape scale). Predicted densities of adult POP are highest on low (<5°) eastern-facing slopes with high sponge coverage (>75%), at depths of 100 to 200 m. By using habitat-based density models with data collected from line transect distance sampling and multibeam acoustic seafloor mapping surveys, we provide an alternative method for estimating rockfish abundance in untrawlable areas, which may help improve rockfish stock assessments and essential fish habitat descriptions and maps.

Inkjet-printed gradient colorimetric indicators for monitoring fish freshness

Gradient colorimetric indicators were developed by piezoelectric inkjet-printing, for monitoring the freshness of packaged fish fillets stored at 4 °C for 7 days. The pH-sensitive indicators involving three sulfonephthalein dyes were printed on inkjet photographic papers and applied as “intelligent” labels that were exposed to the headspace of the packages containing ocean perch, wild haddock or catfish fillets. The printability behaviours of the inks were investigated by determining their density, surface tension, and dynamic viscosity. The indicator labels exhibited striking color changes as the products spoiled during storage, which were correlated with total volatile basic nitrogen, trimethylamine, and dimethylamine levels in the package headspace. The indicators' color profiles observed at different storage times could be discriminated by principal component analysis. From partial least squares regression (R2 > 0.95), the changes of volatile amine contents could be predicted from the indicators' color responses. This proof-of-concept study demonstrates that the innovative gradient indicator is promising for intelligent packaging of fishery and other perishable products.

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.

Exposure assessment of methylmercury in samples of the BfR MEAL Study

The BfR MEAL Study is the first German total diet study and will establish a representative and comprehensive database for dietary exposure assessment in Germany. The present study reports first results of the BfR MEAL Study regarding methylmercury in fish, seafood and mushrooms. In total, 34 MEAL foods were purchased nationally or regionally according to a defined sampling plan, prepared in a representative way for German households, pooled into 49 samples, homogenized and subjected to ICP-MS analysis. Dogfish, tuna, ocean perch, halibut and eel were the fish species with highest MeHg concentrations, while levels in mushrooms and mushroom products had markedly lower MeHg levels. Exposure was estimated by matching the present results with consumption data at appropriate levels of food group aggregation. MeHg exposure for adult high consumers (P 95) exceeded the tolerable weekly intake recommended by the European Food Safety Authority in two age groups (14–17 and 18–24 years). In children, no age group exceeded the recommended tolerable weekly intake. Regional samples differed only slightly in MeHg levels. The differences in exposure found in four regions of Germany were influenced by consumption habits rather than MeHg level in the investigated food.

The Fishery Technology Complex: From Mapping to Depletion of Pacific Ocean Perch, 1880s-1970s.

The rapid collapse of the valuable Pacific Ocean perch fishery in the Gulf of Alaska around the mid-twentieth century is a vivid example of how the development, adoption, and transfer of technology between scientific cultures contributed to a conservation crisis. Technology adopted to support trawl fishery in the Gulf suggests that knowledge of bottom topography, deployment of a full suite of navigational instruments, specialized fishing gear, fleet communications, and positioning systems were key to exploiting and sampling this species of fish. The technologies were transferred to fishers and fishery researchers from a spectrum of sources ranging from academic researchers to natural historians to military agencies. Soviet and Japanese trawl fleets quickly brought about overfishing levels by moving into the region, targeting key fish habitats, and accessing and refining information on the Alaskan continental shelf garnered by American agencies. Technology was applied perversely; it was used to support development of recommendations for reducing exploitation but was also used to assist fishers in fish stock location. In the end, production goals set by managers resulted in over-exploitation.

Estimates of availability and catchability for select rockfish species based on acoustic-optic surveys in the Gulf of Alaska

Fishery-independent surveys, such as bottom trawl surveys, provide time-series abundance estimates, which inform many modern stock assessments. Area-swept biomass estimates from trawl surveys assume that fish densities do not differ between trawlable (T) and untrawlable (UT) areas. Bias and imprecision in the biomass estimates can occur when this assumption is not met. Thus, reliable estimates are needed for both the extent of T and UT habitat types in the surveyed area, and the relative densities of the fish species in the two habitat types to accurately assess groundfish populations. Acoustics and stereo-camera survey tools were used in the present study to determine the extent of T and UT habitat within 25-km2 bottom trawl survey grid cells historically designated as T/UT. Splitbeam acoustics were used to compare the abundance of rockfishes (Sebastes spp.) between the T/UT grid cell areas. Acoustic data were collected along uniformly spaced transects within 52 T and 43 UT grid cells throughout the Gulf of Alaska during summers 2013, 2015, and 2017. The acoustic backscatter attributed to rockfishes in UT grid cells was approximately three times that in T cells, and the percentages available to the bottom trawl survey were 40 % for harlequin rockfish, 43 % for northern rockfish, 51 % for dusky rockfish, and 98 % for Pacific ocean perch (POP). These findings allowed for estimation of the trawl catchability coefficient (q; a scaler between estimates of the area-swept survey abundance and actual abundance) of 0.46 for harlequin rockfish, 0.50 for northern rockfish, and 0.64 for dusky rockfish, and 1.15 for POP. These values could be used to inform the relationship between trawl survey estimated and actual abundances of rockfishes to improve the accuracy of stock assessments for these species.

Characterizing uncertainty in climate impact projections: a case study with seven marine species on the North American continental shelf

AbstractProjections of climate change impacts on living resources are being conducted frequently, and the goal is often to inform policy. Species projections will be more useful if uncertainty is effectively quantified. However, few studies have comprehensively characterized the projection uncertainty arising from greenhouse gas scenarios, Earth system models (ESMs), and both structural and parameter uncertainty in species distribution modelling. Here, we conducted 8964 unique 21st century projections for shifts in suitable habitat for seven economically important marine species including American lobster, Pacific halibut, Pacific ocean perch, and summer flounder. For all species, both the ESM used to simulate future temperatures and the niche modelling approach used to represent species distributions were important sources of uncertainty, while variation associated with parameter values in niche models was minor. Greenhouse gas emissions scenario contributed to uncertainty for projections at the century scale. The characteristics of projection uncertainty differed among species and also varied spatially, which underscores the need for improved multi-model approaches with a suite of ESMs and niche models forming the basis for uncertainty around projected impacts. Ensemble projections show the potential for major shifts in future distributions. Therefore, rigorous future projections are important for informing climate adaptation efforts.