Migratory movements and wintering areas of Leach's Storm‐Petrels tracked using geolocators

Accumulating evidence suggests that Atlantic populations of Leach's Storm‐Petrels (Oceanodroma leucorhoa) are experiencing significant declines. To better understand possible causes of these declines, we used geolocators to document movements of these small (～50‐g) pelagic seabirds during migration and the non‐breeding period. During 2012 and 2013, movement tracks were obtained from two birds that traveled in a clock‐wise direction from two breeding colonies in eastern Canada (Bon Portage Island, Nova Scotia, and Gull Island, Newfoundland) to winter in tropical waters. The bird from Bon Portage Island started its migration towards Cape Verde in October, arrived at its wintering area off the coast of eastern Brazil in January, and started migration back to Nova Scotia in April. The bird from Gull Island staged off Newfoundland in November and then again off Cape Verde in January before its geolocator stopped working. Movements of Leach's Storm‐Petrels in our study and those of several other procellariiforms during the non‐breeding period are likely facilitated by the prevailing easterly trade winds and the Antilles and Gulf Stream currents. Although staging and wintering areas used by Leach's Storm‐Petrels in our study were characterized by low productivity, the West Africa and northeastern Brazilian waters are actively used by fisheries and discards can attract Leach's Storm‐Petrels. Our results provide an initial step towards understanding movements of Leach's Storm‐Petrels during the non‐breeding period, but further tracking is required to confirm generality of their migratory routes, staging areas, and wintering ranges.     

THE FOODS OF GREAT AND SOOTY SHEARWATERS PUFFINUS GRAVIS AND P. GRISEUS IN EASTERN CANADIAN WATERS

The foods of Great and Sooty Shearwaters Puffinus gravis and P. griseus are described from birds collected off eastern Canada. There was a broad overlap in diet, but Great Shearwaters tended to take more squid and tough-bodied fish such as mackerel Scomber scombrus while Sooties took more euphausiids Meganyctiphanes norvegica and soft-bodied fish such as Herring Clupea harengus . These differences are apparently related to differences in bill structure and in the degree of adaptation to underwater swimming.
The birds appeared to feed opportunistically on whatever prey was locally available in the size-range between euphausiids and small fish and squid: Meganyctiphanes off southwest Nova Scotia, spawning and post-spawning capelin Mallotus villosus off eastern Newfoundland, and migrating squid Illex illecebrosus on the Grand Bank. Possible factors influencing prey selection are discussed. It is suggested that the timing and routes of the birds' migrations in the North Atlantic are related to the exploitation of such local concentrations.
Despite the overlap in diets, differences in the distributions of the two species rule out the possibility of significant competition for common food resources.     

The Acanthocolpidae (Digenea) of fishes from the north-east Atlantic: the status of Neophasis Stafford, 1904 (Digenea) and a study of North Atlantic forms

The genus Neophasis is defined. The taxonomic status of the genus is discussed in the light of its life-cycle, hosts and cercarial and adult morphology. It is considered to be closest to the family Acanthocolpidae due to the utilisation of a fish second intermediate host, the form of the cercarial excretory system and, in the adult, the presence of a uterine seminal receptacle and the absence of an external seminal vesicle. The taxonomic value of morphological features are discussed and a key to the north Atlantic species given. The following species are described: Neophasis oculatus (Levinsen) from Myoxocephalus scorpius off West Greenland (type-material), Norway and Denmark, Lycodes esmarkii off NW Scotland and the Faroes, and L. vahli off Newfoundland; N. burti n. sp. (distinguished from N. oculatus by sucker-ratio and testicular configuration) from Myoxocephalus octodecemspinosus off Nova Scotia (type-locality) and New Brunswick, also? immature in Gadus morhua from the Gulf of St. Lawrence; N. anarrhichae (Nicoll) from Anarhichas lupus in the North Sea and off the Faroes; and N. pusilla Stafford from A. lupus off ‘eastern Canada’ (type-material) and Nova Scotia. The only other species in the genus is N. symmetrorchis Machida from the NW Pacific Ocean.     

Results of satellite tagging of Atlantic bluefin tuna, <Emphasis Type="Italic">Thunnus thynnus</Emphasis>, off the coast of Ireland

Pop-up satellite archival tags were attached to six Atlantic bluefin tuna (Thunnus thynnus) off the west coast of Ireland in autumn 2003 and 2004. The satellite tags measured pressure, ambient temperature and light for the term of deployment. Radio pop-up satellite endpoint positions, light and sea surface temperature estimations of geolocation indicate that two fish tagged minutes apart off the coast of County Donegal, migrated to the eastern and western Atlantic Ocean over the following 8 months. The two fish were 5218 km apart at the termination of the experiment. After tagging in September and popping up the following March and April, one fish had traveled to the western Atlantic while the other was located in the waters off the southwest coast of Portugal. A third fish tagged off the coast of County Donegal in October 2004 moved into the Mediterranean Sea and was caught by a fishing vessel southeast of Malta on 11 June 2005. The results link bluefin tuna feeding on European foraging grounds with known eastern breeding regions and western Atlantic waters.     

SUMMER DISTRIBUTION OF PELAGIC BIRDS OFF THE COAST OF ARGENTINA

Eighteen species of sea–birds were observed from CSS 'Hudson' in the South Atlantic between the Rio de la Plata and Tierra del Fuego in late January and late February 1970. Major feeding areas were noted off Mar del Plata, the Valdes Peninsula and Tierra del Fuego, Argentina, the first two in rich modified or unmodified water of the subantarctic Falkland Current, associated with upwelling. The southernmost area had most birds, the northernmost fewest. A temperate–latitude assemblage including Yellow–nosed Albatross and Cory's Shearwater occurred off Mar del Plata in warmed water of subantarctic (Falkland Current) origin. South of 39°S these two species were replaced by Black–browed Albatross and Great Shearwater in cold offshore water of the Falkland Current. Off the Valdes Peninsula Black–browed Albatross, Great and Sooty Shearwaters, White–chinned Petrels and family groups of Magellanic Penguins occurred near the edge of highly–productive water of the Falkland Current. The largest feeding area, east of Tierra del Fuego, had Magellanic and Rockhopper Penguins, Great Shearwaters, King Cormorants, South American Terns and jaegers, but no oceanographic information is available. At 50°S prions and diving petrels appeared for the first time, marking a possible oceanographic discontinuity or proximity to colonies on the Falkland Islands. Several common species of the South Atlantic were not seen on the transect including Cape Pigeon, Southern Fulmar, Soft–plumaged Petrel, Schlegel's Petrel and Pediunker. Kelp Gull, South American Tern, Manx Shearwater and jaegers were rare or absent far from land. New southern limits for the western South Atlantic Ocean were established for Cory's and Manx Shearwaters, and the Great Shearwater was observed for the first time in Chilean waters.     

Biologging, remotely-sensed oceanography and the continuous plankton recorder reveal the environmental determinants of a seabird wintering hotspot

Marine environments are greatly affected by climate change, and understanding how this perturbation affects marine vertebrates is a major issue. In this context, it is essential to identify the environmental drivers of animal distribution. Here, we focused on the little auk (Alle alle), one of the world's most numerous seabirds and a major component in Arctic food webs. Using a multidisciplinary approach, we show how little auks adopt specific migratory strategies and balance environmental constraints to optimize their energy budgets. Miniature electronic loggers indicate that after breeding, birds from East Greenland migrate >2000 km to overwinter in a restricted area off Newfoundland. Synoptic data available from the Continuous Plankton Recorder (CPR) indicate that this region harbours some of the highest densities of the copepod Calanus finmarchicus found in the North Atlantic during winter. Examination of large-scale climatic and oceanographic data suggests that little auks favour patches of high copepod abundance in areas where air temperature ranges from 0°C to 5°C. These results greatly advance our understanding of animal responses to extreme environmental constraints, and highlight that information on habitat preference is key to identifying critical areas for marine conservation.     

Feeding habits the Pacific cod <Emphasis Type="Italic">Gadus macrocephalus</Emphasis> in oceanic waters of the Northern Kuril Islands and Southeast Kamchatka

This study examines the feeding habits of the Pacific cod Gadus macrocephalus in waters off the eastern coast of the northern Kuril Islands and southern Kamchatka. In November–December 1996, the cod primarily consumed fish, which made up 47.6% of the total food mass. The proportion of cephalopods, fishery offal discarded from fishing vessels, and decapods did not exceed 18.5, 17.4, and 12.2%, respectively. Among fishes, the main prey item of the cod was atka mackerel (15.4%); among cephalopods, octopus (16.8%); among fishery offal, heads of atka mackerel (14.2%); and among decapods, majid crabs (6.4%). The rather low percentage of walleye pollock (7.3%) in the cod diet was due to the decline of the east-Kamchatka walleye pollock stock.     

Foraging interactions between Wandering Albatrosses Diomedea exulans breeding on Marion Island and long-line fisheries in the southern Indian Ocean

Wandering Albatrosses Diomedea exulans are frequently killed when they attempt to scavenge baited hooks deployed by long-line fishing vessels. We studied the foraging ecology of Wandering Albatrosses breeding on Marion Island in order to assess the scale of interactions with known long-line fishing fleets. During incubation and late chick-rearing, birds foraged further away from the island, in warmer waters, and showed high spatial overlap with areas of intense tuna Thunnus spp. long-line fishing. During early chick-rearing, birds made shorter foraging trips and showed higher spatial overlap with the local Patagonian Toothfish Dissostichus eleginoides long-line fishery. Tracks of birds returning with offal from the Toothfish fishery showed a strong association with positions at which Toothfish long-lines were set and most diet samples taken during this stage contained fishery-related items. Independent of these seasonal differences, females foraged further from the islands and in warmer waters than males. Consequently, female distribution overlapped more with tuna long-line fisheries, whereas males interacted more with the Toothfish long-line fishery. These factors could lead to differences in the survival probabilities of males and females. Non-breeding birds foraged in warmer waters and showed the highest spatial overlap with tuna long-line fishing areas. The foraging distribution of Marion Island birds showed most spatial overlap with birds from the neighbouring Crozet Islands during the late chick-rearing and non-breeding periods. These areas of foraging overlap also coincided with areas of intense tuna long-line fishing south of Africa. As the population trends of Wandering Albatrosses at these two localities are very similar, it is possible that incidental mortality during the periods when these two populations show the highest spatial overlap could be driving these trends.     

Contrasting trends in gray seal (Halichoerus grypus) pup production throughout the increasing northwest Atlantic metapopulation

The northwest Atlantic subspecies of gray seal (Halicheorus grypus grypus) has been increasing for more than a half century and has reestablished breeding colonies in Canadian and US waters. In 2016, visual, oblique, and vertical large-format digital photographic surveys were conducted at all known breeding colonies in the northwest Atlantic. Total pup production in the northwest Atlantic was estimated to be 109,000 (SE = 17,500) pups. At 87,500 (SE = 15,100) pups, Sable Island accounts for 80% of total pup production. Regional differences in pup production trends are evident. Pup production in the Gulf of St. Lawrence and along the eastern shore of Nova Scotia has been relatively stable. Since 2004, the rate of increase in pup production at Sable Island has slowed to about 5%–7% per year, while the newer colonies in southwest Nova Scotia and the northeastern United States are increasing rapidly. In 2016, the Muskeget Island (MA) breeding colony produced 3,900 (SE = 200) pups, making it the third largest breeding colony in the northwest Atlantic. This southward shift in production may reflect climate-mediated changes in population growth as well as reestablishment of colonies throughout the former range associated with increased protection.     

Identification of infectious salmon anaemia virus in Atlantic salmon from Nova Scotia (Canada): evidence for functional strain differences

Infectious salmon anaemia (ISA) is a serious disease responsible for high morbidity in farmed Atlantic salmon Salmo salar in Norway, Scotland and New Brunswick, Canada. Recent attempts to identify different strains of ISA virus (ISAV) based on nucleotide sequence variation have shown that the Norwegian and Scottish samples are similar to one another but markedly different from New Brunswick samples. These data may suggest the presence of different strains on each side of the Atlantic but no functional difference has been found with either strain. We describe the first identification and characterisation of ISAV in Atlantic salmon from Nova Scotia, Canada. Further, salmon infected with the Nova Scotia ISAV do not show typical ISAV pathology or mortality. Sequencing of this new strain showed it to possess greater similarity to ISAV from Norway and Scotland than to ISAV from New Brunswick. These findings are discussed in terms of a possible origin of the Nova Scotia ISAV strain and the existence of an avirulent ISAV strain. The impact of current strain variation studies on our knowledge of ISAV is also discussed.     

Microsatellite loci reveal highly significant genetic differentiation among Atlantic salmon (Salmo salar L.) stocks from the east coast of Canada

Allele frequency data from eight microsatellite loci provide evidence of highly significant genetic differentiation among stocks of Atlantic salmon Salmo salar L. from the Bay of Fundy, eastern and north-western Nova Scotia and Newfoundland. Estimates of genetic structure ( R _ST and θ) were significant both among all samples taken from the different geographical locations and among samples from geographical regions for which more than one stock was sampled. Samples from the Bay of Fundy taken from stocks which are phenotypically and behaviourally diverse showed particularly high levels of genetic structure. Rogers', allele sharing and (δμ)² distances also revealed significant differences among stock samples and were significantly correlated [Rogers' and (δμ)²] with sea distance between rivers. Results suggest that stocks of Atlantic salmon in eastern Canada are highly diverse genetically and that this should be an important consideration in any management programme for stocks in the area.     

Growth and Age of the Roughhead Grenadier <Emphasis Type="Italic">Macrourus berglax</Emphasis> in Waters off Southwest Greenland

Data on the age and growth of the roughhead grenadier Macrourus berglax from waters off Southwest Greenland have been obtained based on the analysis of otoliths. Specimens with a preanal length of 5?39 cm, a weight of 7?5275 g, and age from 2 to 22 years are recorded in trawl catches. Roughhead grenadier exhibits a similar rate of linear growth in waters off Southwest Greenland and other parts of the range in the Northwest Atlantic. No considerable differences from the rate of the linear growth calculated earlier from scales for the species in waters off West Greenland have been found. In the recent period, the rate of weight gain in roughhead grenadier in waters off Southwest Greenland has been lower than in the Northwest Atlantic in the first half of the 1980s. The age of mass maturation in males (7–9 years) and females (16–17 years) in waters off West and East Greenland is somewhat higher than in coastal waters of Norway and the Northwest Atlantic.     

Polychaete diversity in the Scotia Arc benthic realm: Are polychaetes tracers for faunal exchange?

The Scotia Arc is the only shallow-water and island bridge linking nowadays Patagonia and the Antarctic. The Antarctic Circumpolar Current as an oceanographic peculiarity makes this region an interesting biogeographic transition zone, because this frontal system traditionally is said to isolate the Antarctic fauna from that of the adjacent northern ecosystems. Based on benthos samples from three expeditions onboard R/V Polarstern, we studied distribution patterns of 200 polychaete species and 34 major benthic taxa in order to evaluate the role of polychaetes in the benthic realm of this part of the Southern Ocean. ANOSIM test distinguished three station groups: the central eastern Scotia Sea, the continental shelf off South America and stations at the tip of the Antarctic Peninsula. These station groups differed in organism densities and diversities with stations at the tip of the Antarctic Peninsula hosting the most diverse and dense community. The polychaete diversity patterns in the three assemblages evidenced closer connectivity between the tip of the Antarctic Peninsula and the central eastern Scotia Sea than between the continental shelf off South America with either the stations off the tip of the Peninsula or the central eastern Scotia Sea. This is probably supported by the Polar Front, which divides the island chain into two branches. Species distribution and community patterns of polychaetes appear to be associated with oceanographic and sediment conditions in this region. Most of the shared species showed the capability to tolerate differences in hydrostatic pressure. We suggest that the islands of the Scotia Sea may constitute a bridge for exchange of benthic species, particularly for polychaetes with eurybathic distribution and high dispersal capabilities.     

Common dolphinfish,Coryphaena hippurus,spawn at their easternmost Atlantic range adjacent to the Mediterranean Sea

This study provides sound evidence of the spawning activity of common dolphinfish (Coryphaena hippurus) in the Gulf of Cadiz (southwest Spain) during summer months. Along with waters off Côte d'Ivoire, this area adjacent to the Mediterranean Sea is the easternmost Atlantic spawning ground documented for the species. All the fish analysed (5 males and 15 females) were at spawning stage, except the smallest female (61.5 cm in fork length), which might not have yet reached sexual maturation. The oceanographic conditions during the samplings were similar to those occurring during the peak spawning season in the Gulf of Mexico. The study results are consistent with recent genetic studies indicating differentiation between Mediterranean and Atlantic dolphinfish populations, with the Strait of Gibraltar representing a boundary between two distinct reproductive units. The present results may contribute to improve the understanding of the dynamics of dolphinfish population and the management of eastern Atlantic and Mediterranean stocks.     

Molecular detection and characterization of nodavirus in several marine fish species from the northeastern Atlantic

Nodaviruses (NNV) are responsible for causing disease outbreaks mainly in hatchery-reared larvae and juveniles of a wide variety of fishes throughout the world. This disease has seriously limited the culture of marine fishes over the last decade. In the Atlantic provinces of Canada, disease caused by a nodavirus was first reported in juvenile Atlantic cod being reared in Nova Scotia, in 1999. More recently, disease outbreaks caused by nodavirus have been identified in hatchery-reared Atlantic cod and haddock in Newfoundland and New Brunswick, respectively, and along the east coast of the USA. The presence of NNV in wild Atlantic cod adults and wild winter flounder has also been reported. Nodaviruses were isolated from cultured Atlantic cod and haddock, as well as from wild winter flounder from a variety of geographical localities, and their virus coat (capsid) protein genes were partially sequenced. An analysis of the data indicates that all of the nodaviruses isolated from eastern North America were closely related to one another, but that they were distinct from the European isolates already sequenced. Regardless of host species, isolates from close geographical localities were more similar than those from distant geographical areas. At the protein level, differences in coat protein sequences were seen only for strains isolated from Atlantic cod originating from Newfoundland. Our results suggest that NNV may have been present in the Atlantic off Canada and on the east coast of the USA for some time, and has evolved to form a monophyletic group, distinct from other isolates found in cold-water species. Non-lethal methods for detection of NNV are necessary to develop management strategies for this disease, and would be an asset to diagnosticians and producers. Based on the results of this study, new primers were designed and developed for an improved RT-PCR assay able to detect North Atlantic nodaviruses in ovarian fluids, eggs and other tissues. The application of this test to field samples is discussed.     

Distribution and movements of Buller's albatross (Diomedea bulleri) in Australasian seas

Abstract

The distribution and movements of Buller's albatross in Australasian seas are analysed using results of shipborne surveys (13 238 10‐min counts), counts from trawlers, banding data, recoveries on beaches and fishing vessels, and records from the literature. Patterns of marine distribution are documented by monthly accounts and maps. During the breeding season, highest abundances are recorded over shelves and slopes off southern New Zealand (The Snares shelf to 41–43°S off the South Island, D. b. bulleri), around the Chatham Islands and over oceanic subtropical waters east of New Zealand (probably D. b. platei), with marked seasonal variations observed off southern New Zealand. Both subspecies disperse mostly outside Australasian waters during the non‐breeding season. Birds banded on The Snares were recovered off south‐eastern New Zealand (Stewart Island to Cook Strait) and in the eastern tropical Pacific. Immatures accounted for only 0.25% of birds censused during the ship‐borne surveys; they are recorded around the New Zealand mainland in August‐October and February‐May, off south‐eastern Australia and in the Tasman Sea in November‐December, February, and June‐July. Around New Zealand, males predominate among birds recovered along the eastern seaboard, whereas the sex ratio in south‐western waters tends to vary according to water depth and season. Distribution patterns and movements in New Zealand and Australian seas are discussed in relation to breeding events and breeding status.     

Coral diversity and disease in Mexico

A total of 14 viral haemorrhagic septicaemia virus (VHSV) isolates obtained from Greenland halibut Reinhardtius hippoglossoides caught at the Flemish Cap, a fishing ground in the North Atlantic Ocean near Newfoundland, were characterised using restriction fragment length polymorphism (RFLP) and nucleotide sequence analysis. RFLP analysis was performed on a 1259 bp fragment of the glycoprotein (G) gene, and a 305 nucleotide region within the nucleoprotein (N) gene was used for sequence analysis. Representative strains of the 4 established genotypes were employed for comparative purposes. Sequencing analysis indicated that the Flemish cap isolates grouped in Genotype 3, which also includes isolates from wild fish caught in the North Sea and coastal waters of the UK and Ireland, isolates derived from outbreaks of VHS in turbot farms in the British Isles, and an isolate from European eel Anguilla anguilla caught in northern France. Characterisation using RFLPs resulted in the development of a simple and reliable method of typing VHSV at the genotype level using a 2-step restriction analysis (2-SRA) assay.     

Population biology of the myctophid fish Gymnoscopelus nicholsi (Gillbert, 1911) from the western South Atlantic

Thirty-three collections of Gymnoscopelus nicholsi were made between 1976 and 1981 in the South Atlantic using both krill and bottom trawls. In the Antarctic waters the main part of the stock consisted of adult fish 3–7 years old, characterized by a benthopelagic mode of life. Fish of year-class I were observed only in the vicinity of South Georgia, South Sandwich Islands and the Scotia Sea; year-class II individuals were absent from Antarctic samples. In the notal zone of the western South Atlantic, fish aged 1–5 years were found. The existence of only one population in the region is a possible explanation of these findings: this population is divided into a pelagic stock of juveniles and sub-adults which occur in the offshore waters of the western South Atlantic and benthopelagic stocks of adults distributed over the slope regions off Argentina, South Georgia and Antarctic archipelagos.
The computed values of K (von Bertalanffy growth) were 0.48, 0.41 and estimated total annual instantaneous mortality rates (Z) were 0.45, 0.67, and 0.70 for South Georgia, South Shetlands and notal zone of western South Atlantic stocks, respectively.     

Depth and temperature associations of haddock Melanogrammus aeglefinus off southern Newfoundland

Using data collected as part of offshore surveys conducted during 1972–2013, haddock Melanogrammus aeglefinus association patterns with depth and temperature in southern Newfoundland waters, the northern extremity of the species' range in the western Atlantic Ocean, were quantified. They were typically concentrated in the deep warm waters along the narrow shelf slope in North‐west Atlantic Fisheries Organization Divisions 3O and 3P with individuals moving seasonally into the shallow waters of the banks as they warmed. While M. aeglefinus were found over a range of depths and temperatures, they were primarily located at depths deeper and temperatures warmer than the median sampled. Analyses demonstrated that of the two hydrographic variables assessed, temperature was most influential in structuring distribution, with individuals appearing to change depth in order to maintain similar temperature throughout the year. Melanogrammus aeglefinus were found predominantly in temperatures of c. 4–8° C which often represented some of the warmest waters available. Differences in fish‐habitat association patterns in relation to sex or maturity status were not readily apparent from the analyses. Warming conditions off Newfoundland and Labrador in recent years might be predicted to improve local M. aeglefinus productivity.