Pelagic Surveys Research Articles

Spatial Distribution and Genetic Diversity of Turbot (Scophthalmus maximus, Linnaeus, 1758) in Bulgarian Black Sea Waters Relative to Fishing Pressure and Their Abiotic Environment

The present study examined the genetic diversity and spatial distribution of turbot (Scophthalmus maximus), an economically important species on the Bulgarian Black Sea coast. Maximum entropy (MaxEnt) modeling software Version 3.4.4. was utilized to develop a habitat suitability model for S. maximus in the Bulgarian Black Sea region. Data collected via demersal and pelagic surveys and genetic sampling from 2017 to 2021 were utilized to link species occurrence localities with selected abiotic factors. Our findings showed that the species’ habitat preferences are strongly influenced by temperature and dissolved oxygen, and projections based on simplified climatic scenarios indicated potential distribution shifts and a substantial reduction in reproduction habitats in the northern region. The assessment of genetic diversity was based on mtDNA COIII sequencing; MtDNA revealed a low level of polymorphism in all analyzed populations. The extensive fishing pressure may have increased the likelihood of genetic and population bottlenecks and a consequent decline in genetic diversity in the Shabla, Nesebar, and Tsarevo populations. The Tajima’s D values for the latter indicated that turbot underwent a bottleneck followed by rapid population expansion. Our findings are essential for the conservation and effective management of S. maximus stocks in the region.

Habitat suitability models of five keynote Bulgarian Black Sea fish species relative to specific abiotic and biotic factors

Over the past few years, predicting species spatial distributions has been recognized as a powerful tool for studying biological invasions in conservation biology and planning, ecology, and evolutionary biology. Species spatial distribution models (SDMs) are used extensively for assessing the effects of changes in habitat suitability, the impacts of climate change, and the realignment of the existing conservation priorities. SDMs relate known patterns of species occurrences to a specific set of environmental conditions. Accordingly, we have used MaxEnt SDM tool in order to provide habitat suitability models of 5 keynote fish species: European sprat (Sprattus sprattus L.), red mullet (Mullus barbatus, L.), horse mackerel (Trachurus mediterraneus, L.), bluefish (Pomatomus saltatrix, L.) and whiting (Merlangius merlangus, L.), inhabiting the Bulgarian region of the Black Sea. Presence-only (PO) data collected by pelagic surveys performed between 2017 and 2019 was further utilized to link known species occurrence localities with selected abiotic factors, such as surface sea temperature and salinity, dissolved oxygen, and speed of currents. Biotic interactions were also considered for fitting the patterns of habitat suitability models. The SDMs, obtained from the present research study, prove to have satisfactory predictive accuracy to be further implemented for conservation measures and planning, stock management policy-making, or ecological forecasting.

Spring distribution of capelin <i>Mallotus villosus catervarius</i> in the eastern part of the Sea of Okhotsk in 2000–2019

Data on the local distribution of capelin in the eastern part of the Sea of Okhotsk in 2000–2019 are very limited. Maps of the distribution were made based on results of complex pelagic surveys in 2000–2019. It is demonstrated, that spring distribution of capelin in the Eastern Sea of Okhotsk varied depending temperature conditions in each particular year. Major aggregations of capelin were observed within Shelikhov Gulf in spring. In the “cold” years these aggregations were in the south-western part of the West Kamchatkan shelf, and in the “warm” years – in the north-western part. In sense of bathymetric distribution the main body of the capelin aggregations was observed in the upper part of the shelf at the depth <125 m at the temperatures bit lower zero.

Recent Ecosystem Disturbance in the Northern California Current

An extended marine heat wave occurred across the North Pacific during 2014–2016, including the formation of the warm “Blob” followed by a strong El Niño in 2016. Coincident with this marine heat wave, we documented unprecedented biological changes in plankton and nekton in the Northern California Current (NCC) within pelagic surveys conducted over 20 years (1998–2017). The recent warm period was dominated by warmwater gelatinous invertebrates and fishes, some of which were previously either extremely rare or absent. Mixing of organisms originating from more southern or western regions with those previously present in the NCC may have resulted in novel and unpredictable trophic interactions that produced some of the observed changes in relative abundance. Continued long‐term monitoring is needed to determine whether this is a temporary ecosystem disturbance or a fundamental change in the very productive NCC upwelling region.

Habitat associations of cetaceans and seabirds in the tropical eastern Indian Ocean

There is an increasing demand for integrated pelagic surveys to support ecosystem-based management of marine environments and their associated marine life. The Browse Basin in the tropical eastern Indian Ocean was surveyed using ship line transects to determine habitat associations of cetaceans and seabirds with submarine topography and local oceanographic conditions during winter and spring 2008. Fourteen species of cetaceans, including the data deficient pygmy blue whale, and 23 species of seabirds were encountered throughout the basin. Aggregations of both cetaceans and seabirds were observed at two significant submarine topographic features, Scott Reef and Browse Cliffs, particularly during spring when encounters and abundances of odontocetes were far greater. The attraction of cetaceans and seabirds to Scott Reef and Browse Cliffs was likely foraging-related given these features were associated with upwelling and elevated biomass of krill and fish. Sub-mesoscale sea surface temperature and chlorophyll a fronts also occurred in vicinity to Browse Cliffs and the shelf environment. The Browse Basin is an important, and potentially predictable, foraging ground for a variety of top predators, and their occurrence would have implications for the current and future management practices of oil and gas industries operating in the region.

Species-specific residence times in the aft part of a pelagic survey trawl: implications for inference of pre-capture spatial distribution using the Deep Vision system

Abstract In-trawl camera systems promise to improve the resolution of trawl sampling used to ground-truth the interpretation of acoustic survey data. In this study, the residence time of fish in front of the Deep Vision camera system, used to identify, measure and count fish inside the trawl, was analysed to determine the reliability of spatial distribution recorded by the system. Although Atlantic herring (Clupea harengus), haddock (Melanogrammus aeglefinus), and most Atlantic cod (Gadus morhua) moved quickly back through the aft part of the pelagic trawl, saithe (Pollachius virens) spent up to 4 min in front of the system. The residence time increased for saithe and cod when other individuals were present, and cod swimming in the low water flow close to the trawl netting spent longer there than cod at the centre of the trawl. Surprisingly, residence time was not related to the size of the fish, which may be explained by the collective behaviour of shoaling fish. Our findings suggest that while in-trawl images can be used to identify, measure and count most species, when sampling fast-swimming species such as saithe the position inferred from when they were imaged may not reflect the actual spatial distribution prior to capture.

North Atlantic right whale Eubalaena glacialis occurrence in offshore wind energy areas near Massachusetts and Rhode Island, USA

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 34:45-59 (2017) - DOI: https://doi.org/10.3354/esr00827 North Atlantic right whale Eubalaena glacialis occurrence in offshore wind energy areas near Massachusetts and Rhode Island, USA S. M. Leiter1,*, K. M. Stone1, J. L. Thompson2, C. M. Accardo2, B. C. Wikgren1, M. A. Zani1, T. V. N. Cole3, R. D. Kenney4, C. A. Mayo2, S. D. Kraus1 1New England Aquarium, Boston, MA 02110, USA 2Center for Coastal Studies, Provincetown, MA 02657, USA 3NOAA Northeast Fisheries Science Center, Woods Hole, MA 02543, USA 4University of Rhode Island Graduate School of Oceanography, Narragansett, RI 02882, USA *Corresponding author: sleiter@neaq.org ABSTRACT: Recent surveys of wind energy areas offshore of Massachusetts and Rhode Island (USA) have demonstrated that they encompass habitat used by the Endangered North Atlantic right whale Eubalaena glacialis. Prior to 2011, little systematic survey effort had been conducted in the area. The Bureau of Ocean Energy Management and the state of Massachusetts supported 3.5 yr of twice-monthly aerial surveys by the Northeast Large Pelagic Survey Collaborative (NLPSC). Additional survey teams including the Northeast Fisheries Science Center and the Center for Coastal Studies have collected sightings data in the region. Data systematically collected by the NLPSC allowed analyses of monthly sightings rates, sightings per unit effort, and hot spots which provided information on current temporal and spatial use patterns. Abundance estimates for each season-year (i.e. a 3 mo period within a given survey year) were calculated. Behaviors observed included feeding and surface active groups. Photo-identification of whales since 2010 yielded a minimum count of 196 unique individuals (annual average = 35), or over one-third of the current population estimate. Analyses of demographics of these individuals revealed that 34 known calving females (30% of the total currently presumed alive) visited the study area. These results demonstrate consistent annual use of this area by a significant portion of the E. glacialis population, with a strong correlation between season and presence. These findings can inform management activities and development planning, and be used as a baseline dataset for assessing long-term impacts to the species. KEY WORDS: North Atlantic right whale · Eubalaena glacialis · Wind energy area · Distribution · Abundance · Behavior · Demographics Full text in pdf format PreviousNextCite this article as: Leiter SM, Stone KM, Thompson JL, Accardo CM and others (2017) North Atlantic right whale Eubalaena glacialis occurrence in offshore wind energy areas near Massachusetts and Rhode Island, USA. Endang Species Res 34:45-59. https://doi.org/10.3354/esr00827 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 34. Online publication date: July 21, 2017 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2017 Inter-Research.

Pelagic zonation of water quality and phytoplankton in the Great Lakes

Analysis of aquatic ecosystem data collected from large water bodies must consider spatial variations. A suite of pelagic survey stations exists for the Laurentian Great Lakes, but little is known about their redundancy. We present a strategy to delineate the lakes into zones based on water quality and phytoplankton biovolume. Water samples were collected from 72 sites in two seasons (spring and summer) from 2007 to 2010 in all five lakes. Integrated samples were analyzed for phytoplankton biovolume and nine water quality parameters. We conducted cluster analysis, principal components analysis and non-metric multidimensional scaling methods for water quality and phytoplankton taxon-specific biovolume for the Great Lakes basin and for each lake separately. There were significant lake-to-lake differences, and based on lake-specific analyses, Lake Superior, Lake Michigan and Lake Erie were each divided into three zones; Lake Huron and Lake Ontario were each grouped into two zones. The zones identified by water quality and phytoplankton provide an understanding of spatial distributions for evaluating monitoring data.

Some results of researches on pacific herring in the northwestern Bering Sea in 2010-2015

The data of pelagic and bottom surveys on pacific herring in the northwestern Bering Sea obtained in 2010-2015 and its stock assessments by different methods are compared. Some biological parameters of the herring are presented and its spatial distribution and migrations are described. The pelagic surveys with stepped trawling and the bottom trawl surveys are concluded as the best for the herring stock assessment and biological characteristic. The stock state in the 2010-2015 is determined as high abundant due to mass migration of herring from the eastern Bering Sea to its northwestern part that starts in June under certain oceanographic conditions. Different modes of the herring feeding migration are revealed for periods of its high and low stock. The results are used for the herring fishery regulation in the northwestern Bering Sea.

Early epipelagic life-history characteristics of the North Pacific armorhead Pentaceros wheeleri

North Pacific armorhead Pentaceros wheeleri specimens collected through pelagic surveys in the North Pacific were analyzed to estimate the distribution, hatching season, growth, and the duration of the epipelagic life stage. Most pelagic specimens were collected in the central and eastern North Pacific (36–50°N, 178°E–137°W). This area was considered to be the nursery ground where larvae and juveniles inhabit until subsequent settlement to seamounts. The pelagic specimens were aged 0, 1, and 2 years, and their hatching periods were estimated to be from December to February based on the analysis of daily growth increments of otoliths. Standard length-at-age data were fitted to the mixed model of the von Bertalanffy growth curves, and growth coefficients L ∞, k, and t 0 were estimated to be 308 and 290 mm, 0.909 and 1.055, and 0.183 and 0.256 years for males and females, respectively. The standard length of fish at age 2.5 years was estimated at 263–271 mm, which is close to the size of demersal fish commonly harvested from the southern Emperor-northern Hawaiian Ridge seamounts. Since only a few age 3 fish were collected in pelagic samples, presumably most individuals shift to demersal life on seamounts before age 3.

Evidence that summer jellyfish blooms impact Pacific Northwest salmon production

AbstractInterannual variability in salmon (Oncorhynchus spp.) production in the northeast Pacific is understood to be driven by oceanographic variability and bottom‐up processes affecting prey availability to juvenile salmon. Scyphozoan jellyfish have an important role in shaping the pathways of energy flow through pelagic food webs. While jellyfish obtain high production rates and biomasses as major consumers of zooplankton production, they have few predators and may divert plankton production away from higher trophic levels. Although jellyfish are planktivorous and juvenile coho (O. kisutch) and Chinook (O. tshawytscha) salmon are mainly piscivorous, they may be indirect competitors for plankton production. Ecosystem model simulations suggested that among all trophic interactions within the Pacific Northwest coastal food web, juvenile salmon are particularly sensitive to jellyfish blooms, and that salmon production will be suppressed in years of high summer jellyfish biomass. Pelagic surveys off Oregon and Washington (1999–2012) were used to examine the interannual relationship between salmon production and the dominant jellyfish species, the sea nettle Chrysaora fuscescens, off the Pacific Northwest coast. There was a significant, negative correlation between sea nettle biomass and the strength of adult coho and Chinook salmon returns to the Columbia River. Examination of spatial distributions across years showed a positive association between sea nettles and salmon. Within individual years, significant differences between the distribution of sea nettles and yearling coho and Chinook salmon generally occurred during cooler ocean summers, perhaps due to the greater expanse of optimal salmon habitat resulting from more upwelling. Whether the association is behavioral or a product of oceanographic processes, association enhances the opportunity for indirect competition. Examination of feeding incidence in September showed that salmon stomachs were less full at locations with higher sea nettle biomass.

Novel lineage patterns from an automated water sampler to probe marine microbial biodiversity with ships of opportunity

There is a paucity of data on long-term, spatially resolved changes in microbial diversity and biogeography in marine systems, and yet these organisms underpin fundamental ecological processes in the oceans affecting socio-economic values of the marine environment. We report results from a new autonomous Water and Microplankton Sampler (WaMS) that is carried within the Continuous Plankton Recorder (CPR). Whilst the CPR with its larger mesh size (270μm), is designed to capture larger plankton, the WaMS was designed as an additional device to capture plankton below 50μm and delicate larger species, often destroyed by net sampling methods. A 454 pyrosequencing and flow cytometric investigation of eukaryotic microbes using the partial 18S rDNA from thirteen WaMS samples collected over three months in the English Channel revealed a wide diversity of organisms. Alveolates, Fungi, and picoplanktonic Chlorophytes were the most common lineages captured despite the small sample volumes (200–250ml). The survey also identified Cercozoa and MAST heterotrophic Stramenopiles, normally missed in microscopic-based plankton surveys. The most common was the likely parasitic LKM11 Rozellomycota lineage which comprised 43.2% of all reads and are rarely observed in marine pelagic surveys. An additional 9.5% of reads belonged to other parasitic lineages including marine Syndiniales and Ichthyosporea. Sample variation was considerable, indicating that microbial diversity is spatially or temporally patchy. Our study has shown that the WaMS sampling system is autonomous, versatile and robust, and due to its deployment on the established CPR network, is a cost-effective monitoring tool for microbial diversity for the detection of smaller and delicate taxa.

Spatially explicit estimates of stock sizes, structure and biomass of herring and blue whiting, and catch data of bluefin tuna

Abstract. The North Atlantic is a productive marine region which has supported important commercial fisheries for centuries. Many of these fisheries have exploited the pelagic species, including herring, blue whiting and tuna. Here we present data on the distribution of herring and blue whiting based on the international ecosystem survey in the Nordic Seas (IESNS), the bottom trawl survey in the Bay of Biscay and Celtic Sea (EVHOE) and the pelagic survey in the Bay of Biscay (PELGAS). We also present catch data on bluefin tuna, which has been depleted for decades but historically used to be a key predator on the other pelagic stocks during summer. The results show that there were substantial changes in the herring and blue whiting distribution during the 1990s and early 2000s. The earliest bluefin tuna catches noted were in 1907. The catches in the Norwegian Sea area peaked in the 1950s and there have been very small catches since the 1980s. The reported catches in the Mediterranean, on the other hand, peaked in the late 1990s and subsequently had a strong reduction.

Predicting early life connectivity of Antarctic silverfish, an important forage species along the Antarctic Peninsula

The early life stages of the Antarctic silverfish (Pleuragramma antarctica), an important prey species for higher predators in the Southern Ocean ecosystem, dominate the larval fish assemblages of the Bransfield Strait, one of the most important areas for larval retention off the Antarctic Peninsula. Nevertheless, the spatial location of areas where they were spawned and the timing of larval hatching remain unknown. By linking Lagrangian particle tracking simulations with age data obtained using otolith microincrements from fish caught north of Joinville Island in a pelagic survey, we estimated the distribution of hatch dates and subsequent growth rates of silverfish reaching the Bransfield Strait, and predicted the areas where they were spawned. Larval hatching peaked during the last week of December, and the inner shelf and shelf break, east of the Larsen Ice shelf, were the dominant areas predicted to contribute to larval assemblages in the Bransfield Strait. Over simulated periods of 600–630 days, 35–40% of particles remained within the Bransfield Strait, suggesting an important source of supply to higher predators feeding off the northern Antarctic Peninsula. The daily growth rate at the mean size of 22.3 mm was 0.18 mm, corresponding to a daily change in size of approximately 0.82% standard length (SL), and large variability in growth rate suggested a wide range of environmental conditions experienced during the period of advection from the spawning areas. These results provide spatial predictions that can be tested empirically in future studies, using the simulated trajectories to inform sampling design and spatial coverage.

Bering wolffish Anarhichas orientalis (Anarhichadidae) off the coasts of Sakhalin and the Kuril Islands

According to long-term materials (1978–2012) of bottom and pelagic trawl surveys, the distribution and some features of biology of pelagic juveniles and adult individuals of Bering wolffish Anarhichas orientalis off the coasts of Sakhalin and the Kuril Islands are considered. Maximum sizes and age of wolffish are 113 cm, 10.8 kg, and 14 years. It is shown that the seasonal dynamics of distribution and numbers of pelagic juveniles off the Sea of Okhotsk coasts of southern Sakhalin is closely related to the regime of water warming. It is suggested that considerable variability of size-weight indices of juveniles at the beginning of summer is determined by extension of the dates of spawning of wolffish off the coasts of Sakhalin and the presence of fish from other areas of reproduction. Data on feeding of different size groups of wolffish fingerlings are presented.

Zoogeographical subdivision of the pelagic zone of the western Bering Sea based on nekton species ranges

The subdivision of the western Bering Sea into zoogeographical regions for nekton fauna was carried out using data from 40 pelagic trawl surveys made by the Pacific Fisheries Research Center. The selected approach involves computer methods for plotting a map that describes the spatial distribution of the index of latitudinal zoning in the form of continuous fields. This index is a digital designation of verbally formulated types of latitudinal species areas. Computer mapping of the region was performed based on generalized data; intraday, seasonal, and interannual time aspects; and trawling depths. According to generalized data, almost the entire western part of the Bering Sea belongs to the high-boreal latitudinal subzone. A small area of the low-boreal subzone occurs only in the southeast of the open part of the sea. The average value of the latitudinal zoning index and its variation significantly decreased with increasing depth. From the upper epipelagic to the mesopelagic layer, the degree of subdivision decreased and the results of zoning of the mesopelagic layer were substantially different from all other zoning results.

Evaluating analytical approaches for estimating pelagic fish biomass using simulated fish communities

Pelagic fish assessments often combine large amounts of acoustic-based fish density data and limited midwater trawl information to estimate species-specific biomass density. We compared the accuracy of five apportionment methods for estimating pelagic fish biomass density using simulated communities with known fish numbers that mimic Lakes Superior, Michigan, and Ontario, representing a range of fish community complexities. Across all apportionment methods, the error in the estimated biomass generally declined with increasing effort, but methods that accounted for community composition changes with water column depth performed best. Correlations between trawl catch and the true species composition were highest when more fish were caught, highlighting the benefits of targeted trawling in locations of high fish density. Pelagic fish surveys should incorporate geographic and water column depth stratification in the survey design, use apportionment methods that account for species-specific depth differences, target midwater trawling effort in areas of high fish density, and include at least 15 midwater trawls. With relatively basic biological information, simulations of fish communities and sampling programs can optimize effort allocation and reduce error in biomass estimates.

Species distribution modeling of storm-petrels (Oceanodroma furcata and O. leucorhoa) in the North Pacific and the role of dimethyl sulfide

Storm-petrels have been shown to use dimethyl sulfide (DMS) as a foraging cue, suggesting that this compound may be used to predict their distribution. We describe a new distribution model that employs machine learning software and geographic information systems to model storm-petrel distribution. We used environmental predictor variables that included newly available climatologies of sea surface DMS concentrations to construct distribution maps of fork-tailed storm-petrel (Oceanodroma furcata) and Leach’s storm-petrel (O. leucorhoa) in the North Pacific and Bering Sea. Model accuracy was assessed by (1) using the area under the receiver operating characteristic curve (AUC) values and (2) comparing predicted distributions to presence and non-detection data from two opportunistic pelagic surveys performed in summer 2008. Models using all predictor variables gave AUC values of 0.89 and 0.75, sensitivity values of 0.73 and 0.61, and specificity values of 0.83 and 0.73 for fork-tailed and Leach’s storm-petrel, respectively. Models using all predictor variables except DMS gave AUC values of 0.87 and 0.74, sensitivity values of 0.81 and 0.60, and specificity values of 0.77 for fork-tailed and Leach’s storm-petrel, respectively. The large-scale link between DMS and how storm-petrels use it to locate foraging areas was reinforced by the partial dependence of DMS on the relative index of occurrence (RIO) of storm-petrels, and by a decrease in AUC values when removing DMS as a predictor. This work is a preliminary step toward linking seabird distribution to globally important infochemicals and should be a basis for further study.

Escape of blue whiting ( Micromesistius poutassou) and herring ( Clupea harengus) from a pelagic survey trawl

The escape of blue whiting and herring from the aft parts of a pelagic trawl was studied by using small-meshed collection bags. The bags were attached to 80, 100, 200 and 400 mm belly sections in front of the codend of a 640 m pelagic survey trawl. The study was conducted in the springs of 2007, 2008 and 2009 based on two acoustic biomass estimation cruises each year. The results show that, at times, there can be substantial escape from the aft belly of the trawl. For blue whiting, the mean estimated total escape was in the range of 0.6–12%, and for herring, the range was 2–21%. Blue whiting escaped mainly from the 200 mm mesh section and was not recorded behind the 100 mm mesh section. The escapement of herring was recorded in all of the sampled sections of the trawl, mainly from the 80, 200 and 400 mm mesh sections. A length dependent tendency was found for herring for all three years but only for one year for blue whiting (paired t-test). Generally the mean length of escaped fish was lower than of fish in the codend. This can affect the acoustic abundance estimations done with the aid of this trawl. A significant difference between numbers of blue whiting escaping from 100 to 200 mm mesh sections was found, whereas no significant difference was detected between numbers of herring escaping from different mesh sizes (Mann–Whitney U and Kruskal–Wallis tests).

Composition, distribution, and diversity of pelagic fishes around the Canary Islands, Eastern Central Atlantic

Oceanic islands of volcanic origin have a narrow shelf and a steep slope that should lead to considerable spatial overlap among coastal and oceanic fauna. During six pelagic surveys in the Canarian archipelago, Eastern Central Atlantic, over 65,000 fishes belonging to 211 species were collected at depths between 8 and 1035 m. The mesopelagic families of the lanternfishes (Myctophidae) and the bristlemouths (Gonostomatidae) accounted for about 50% of all specimens. By multivariate classification and ordination methods four different assemblages associated with mesopelagic, epipelagic–oceanic or coastal habitats could be identified. Two of these assemblages were coastal, differing in the proportion of meso- and epipelagic species. These data indicate intense horizontal migrations of mesopelagic fishes (mainly Myctophidae) into the neritic realm and increased interactions between coastal and oceanic habitats. Alpha diversity indices were higher and dominance was lower in oceanic habitats compared to the coastal realm. No marked differences among oceanographically similar areas of the entire archipelago were found. Beta diversity as a measure of similarity among sites or samples revealed variabilities between areas south of Gran Canaria and Fuerteventura islands. A considerable heterogeneity in species distribution was found off SE Fuerteventura in an area with high hydrographic variability. Therefore, both topography and hydrography are important factors influencing the distribution and abundance of pelagic fishes in this oceanic archipelago.