Greenland Shark Research Articles

Exposure and effects assessment of persistent organohalogen contaminants in arctic wildlife and fish

Persistent organic pollutants (POPs) encompass an array of anthropogenic organic and elemental substances and their degradation and metabolic byproducts that have been found in the tissues of exposed animals, especially POPs categorized as organohalogen contaminants (OHCs). OHCs have been of concern in the circumpolar arctic for decades. For example, as a consequence of bioaccumulation and in some cases biomagnification of legacy (e.g., chlorinated PCBs, DDTs and CHLs) and emerging (e.g., brominated flame retardants (BFRs) and in particular polybrominated diphenyl ethers (PBDEs) and perfluorinated compounds (PFCs) including perfluorooctane sulfonate (PFOS) and perfluorooctanic acid (PFOA) found in Arctic biota and humans. Of high concern are the potential biological effects of these contaminants in exposed Arctic wildlife and fish. As concluded in the last review in 2004 for the Arctic Monitoring and Assessment Program (AMAP) on the effects of POPs in Arctic wildlife, prior to 1997, biological effects data were minimal and insufficient at any level of biological organization. The present review summarizes recent studies on biological effects in relation to OHC exposure, and attempts to assess known tissue/body compartment concentration data in the context of possible threshold levels of effects to evaluate the risks. This review concentrates mainly on post-2002, new OHC effects data in Arctic wildlife and fish, and is largely based on recently available effects data for populations of several top trophic level species, including seabirds (e.g., glaucous gull ( Larus hyperboreus)), polar bears ( Ursus maritimus), polar (Arctic) fox ( Vulpes lagopus), and Arctic charr ( Salvelinus alpinus), as well as semi-captive studies on sled dogs ( Canis familiaris). Regardless, there remains a dearth of data on true contaminant exposure, cause–effect relationships with respect to these contaminant exposures in Arctic wildlife and fish. Indications of exposure effects are largely based on correlations between biomarker endpoints (e.g., biochemical processes related to the immune and endocrine system, pathological changes in tissues and reproduction and development) and tissue residue levels of OHCs (e.g., PCBs, DDTs, CHLs, PBDEs and in a few cases perfluorinated carboxylic acids (PFCAs) and perfluorinated sulfonates (PFSAs)). Some exceptions include semi-field studies on comparative contaminant effects of control and exposed cohorts of captive Greenland sled dogs, and performance studies mimicking environmentally relevant PCB concentrations in Arctic charr. Recent tissue concentrations in several arctic marine mammal species and populations exceed a general threshold level of concern of 1 part-per-million (ppm), but a clear evidence of a POP/OHC-related stress in these populations remains to be confirmed. There remains minimal evidence that OHCs are having widespread effects on the health of Arctic organisms, with the possible exception of East Greenland and Svalbard polar bears and Svalbard glaucous gulls. However, the true (if any real) effects of POPs in Arctic wildlife have to be put into the context of other environmental, ecological and physiological stressors (both anthropogenic and natural) that render an overall complex picture. For instance, seasonal changes in food intake and corresponding cycles of fattening and emaciation seen in Arctic animals can modify contaminant tissue distribution and toxicokinetics (contaminant deposition, metabolism and depuration). Also, other factors, including impact of climate change (seasonal ice and temperature changes, and connection to food web changes, nutrition, etc. in exposed biota), disease, species invasion and the connection to disease resistance will impact toxicant exposure. Overall, further research and better understanding of POP/OHC impact on animal performance in Arctic biota are recommended. Regardless, it could be argued that Arctic wildlife and fish at the highest potential risk of POP/OHC exposure and mediated effects are East Greenland, Svalbard and (West and South) Hudson Bay polar bears, Alaskan and Northern Norway killer whales, several species of gulls and other seabirds from the Svalbard area, Northern Norway, East Greenland, the Kara Sea and/or the Canadian central high Arctic, East Greenland ringed seal and a few populations of Arctic charr and Greenland shark.

Study of Alkylglycerol Containing Shark Liver Oil: A Physico Chemical Support for Biological Effect?

Shark liver oil (SLO), is used in natural medicine as immunity stimulant, cardiovascular protector and anti ageingreagent. These properties were related with the high amounts of alkylglycerols (22%) obtained from Greenland shark liver. After a control of the mean SLO composition by NMR and MS, surface and membrane interactions and antioxidant properties were investigated using NMR, ESR and ST measurements and the in vitro consequences on erythrocytes and cells were studied. An estimation of the composition of this extract was performed. Moreover, SLO was found not haemolytic (A concentration inducing 50% haemolysis, HC50 could not be reached) and superficial tension measurements revealed slight tension active properties. The 31P and 2H-NMR and ESR studies of phospholipid dispersions (dimyristoyl phosphatidyl cholin, DMPC) in the presence of SLO showed a significant increase in membrane fluidity at low temperature (below phase transition temperature) predominantly observed at the surface level. The anti oxidant activity was also confirmed, similar as that observed for vitamin E.

Dioxins and PCBs in Greenland shark ( Somniosus microcephalus) from the North-East Atlantic

The Greenland shark ( Somniosus microcephalus) is a high-trophic fish species present in Arctic waters. The present study aimed to determine concentrations of polychlorinated dibenzo- p-dioxins and furans (PCDDs/Fs), dioxin-like (DL) PCBs and six non-dioxin-like (NDL) PCBs in muscle and liver from 10 female Greenland sharks collected between 2001 and 2003 from Icelandic waters. The mean total concentrations of PCDDs/Fs were 13 and 530 pg/g fat for muscle and liver, respectively, and show enrichment in the liver. Concentrations of DL-non- ortho PCBs were also higher in liver compared to muscle with mean concentrations of 7.8 and 0.36 ng/g fat, respectively. No enrichment in the liver was found for DL-mono- ortho- and NDL-PCBs. No correlation was found between the size range studied and total concentrations of the compounds analyzed. Total WHO-TEQs (PCDDs/Fs and DL-PCBs) ranged between 7.1–70 and 54–1500 pg/g fat in muscle and liver, respectively.

Essential and non-essential element concentrations in two sleeper shark species collected in arctic waters

A number of elements/metals have increased in arctic biota and are of concern due to their potential toxicity. Most studies on elements in the Arctic have focused on marine mammals and seabirds, but concentrations in the Greenland shark ( Somniosus microcephalus) and Pacific sleeper shark ( Somniosus pacificus), the only two shark species known to regularly inhabit arctic waters, have never been reported. To address this data gap, concentrations and patterns of 25 elements were analyzed in liver of Greenland sharks collected about Cumberland Sound ( n = 24) and Pacific sleeper sharks collected about Prince William Sound ( n = 14). Several non-essential elements differed between species/locations, which could suggest geographical exposure differences or ecological (e.g., diet) differences between the species. Certain essential elements also differed between the two sleeper sharks, which may indicate different physiological requirements between these closely related shark species, although information on such relationships are lacking for sharks and fish.

Sea Lamprey Attached to a Greenland Shark in the St. Lawrence Estuary, Canada

Abstract A Petromyzon marinus (sea lamprey) was observed attached to an approximately 3-m fork length, male Somniosus microcephalus (Greenland shark) on 9 October 2004 in Baie St. Pancrace, St. Lawrence Estuary, PQ. This is the first report of a sea lamprey attached to a member of Somniosidae.

Movement and environmental preferences of Greenland sharks (Somniosus microcephalus) electronically tagged in the St. Lawrence Estuary, Canada

Three Greenland sharks (Somniosus microcephalus) were tagged with electronic tags, in Baie St. Pancrace, St. Lawrence Estuary, Quebec, Canada. One shark was tagged on 23 July 2004, with an acoustic telemetry tag. Two sharks were each tagged with a pop-up satellite archival tag (PSAT) on 27 August 2004. Two of the sharks remained in or close to the bay, one for 47 days and the other for at least 66 days. The third shark left the bay immediately after tagging on 27 August 2004. This shark entered the main channel of the St. Lawrence Estuary, and had moved 114.9 km upstream by 1 November 2004 when the tag reported to ARGOS satellites. The tags provided a total of 179 days of data on the movement and environmental preferences of Greenland sharks in the St. Lawrence Estuary. Sharks that reported depth and ambient water temperature data from the bay showed significant diel differences in depth preferences and corresponding ambient temperatures. The sharks remained near the bottom of the water column during the day and displayed increased vertical movements at night. The shark that resided in the main channel did not show this pattern, but generally remained at depths between 325 and 352 m. Sharks in the bay experienced water temperatures that ranged from −1.1 to 8.6°C at depths from 0 to 67 m. In the main channel the shark experienced temperatures that ranged from 1.0 to 5.4°C at depths from 132 to 352 m. This is the first report of numerous Greenland sharks inhabiting shallow near shore bays during summer and autumn.

Vision and its Relationship to Novel Behaviour in St. Lawrence River Greenland Sharks, <em>Somniosus microcephalus</em>

Rarely observed Greenland Sharks, Somniosus microcephalus, were recorded at shallow depths by divers employing underwater video in the St. Lawrence River, in association with a seasonal concentration of Capelin (Mallotus villosus) in May-June 2003. We recorded unique proximity-induced display motor patterns in these sharks, which have not been recorded in underwater observations of Arctic Greenland Sharks. Arctic sharks have a high incidence of blindness due to an ocular copepod parasite, Ommatokoita elongata. The absence of parasite-induced blindness in St. Lawrence Greenland Sharks, in contrast to endemic blindness in the Arctic population, may allow sharks in this region to more readily visually recognize the presence of conspecifics and potential prey. Improved visual acuity may therefore allow St. Lawrence River sharks to express a different behavioural repertoire than Arctic sharks, with resulting changes in intra- and inter-specific aggression and predatory behaviour.

Ultrasonic tracking of Greenland sharks, Somniosus microcephalus, under Arctic ice

Six Greenland sharks, Somniosus microcephalus (Bloch and Schneider, 1801), 190–355 cm fork length, were tracked under land-fast sea ice off northern Baffin Island (73.2°N; 85.3°W) between 16 and 28 May 1999, using ultrasonic telemetry. The sharks were tracked continuously for periods of 5.5–13.0 h, with the tracks of two individuals lasting 31.4 and 42.8 h, respectively, each with an interval when the track was lost. Several sharks dove after release and moved along the ocean bottom for the duration of the tracking period, while others varied their movements regarding course and depth. Two sharks made repeated visits to within 11 m of the ice–water interface from deeper water. The tracked sharks exhibited no apparent depth or temperature preferences, and pooled data indicated that sharks remained deep during the morning and gradually moved into shallower depths through the afternoon and night. Rates of descent (average=0.099 m s−1) were significantly greater than rates of ascent (average=0.058 m s−1) for all sharks, and the average rate of horizontal movement over ground was estimated as 0.215 m s−1. Based on the movements of tracked sharks and information contained in the literature, S. microcephalus may prey on seals in areas covered by land-fast sea ice.

A second species of Arctic shark: Pacific sleeper shark Somniosus pacificus from Point Hope, Alaska

We report a dead, 229-cm-long Pacific sleeper shark, Somniosus pacificus, discovered in 1998 along the shore at Point Hope, Alaska. This is the first definitive record of this species from within the Arctic Circle, the first definitive report of a shark from the Chukchi Sea, and the first report of a shark other than a Greenland shark from within the Arctic Circle.

New records for Dinemoura ferox (Copepoda: Siphonostomatoida: Pandaridae) from Pacific sleeper sharks captured in waters off eastern Taiwan.

Four of the 27 Pacific sleeper sharks (Somniosus pacificus Bigelow and Schroeder) captured in the western North Pacific Ocean off eastern Taiwan between 19 March and 18 May 2002 hosted the parasitic copepod Dinemoura ferox (Krøyer, 1838) on their body surface including the fins. This report documents a new host record as well as a new ocean record for D. ferox, which until now has only been reported from the benthopelagic sharks, Somniosus microcephalus (Bloch and Schneider) and Centrophorus squamosus (Bonnaterre), occurring in the north Atlantic Ocean off Greenland and Iceland.

USING ANTHROPOGENIC CONTAMINANTS AND STABLE ISOTOPES TO ASSESS THE FEEDING ECOLOGY OF GREENLAND SHARKS

Organochlorine contaminants (OCs) are a large group of ubiquitous pollutants that have potential as tracers of ecological processes. To examine this utility, we measured OCs, stable isotopes of nitrogen (δ15N) and carbon (δ15C), and stomach contents in a large Arctic marine fish, the Greenland shark (Somniosus microcephalus), collected in the Davis Strait region to examine the feeding ecology of this little studied elasmobranch. Stable isotopes and OCs were also measured in the turbot (Reinhardtius hippoglossoides) and stable isotopes in the ringed seal (Phoca hispida) and harp seal (Pagophilus groenlandicus) to put the shark results in context. Values of δ15N suggest that the Greenland shark feeds at a similar trophic level as the turbot and ringed seal (about the fourth trophic level) and at a higher trophic level than harp seals, despite the presence of many turbot and a single ringed seal in the stomach contents of 14 sharks. Values of δ13C indicate that source of carbon in turbot and Greenland shark ...

Using Anthropogenic Contaminants and Stable Isotopes to Assess the Feeding Ecology of Greenland Sharks

Using Anthropogenic Contaminants and Stable Isotopes to Assess the Feeding Ecology of Greenland Sharks

Isotopic composition of recent shark teeth as a proxy for environmental conditions

The O, C, and Sr isotope compositions of teeth from ten species, belonging to five families, and three orders of sharks were measured to determine the influence of habitat, diet, and possible species-specific fractionation effects on the isotopic composition of biogenic phosphate from fish. The sharks were recently caught in subtropical waters off the KwaZulu-Natal (KZN) coast of South Africa, as well as from cold waters in Prince William Sound (PWS), Alaska, and Victor Bay (VB), Nunavut, Canada. δ 18O values of tooth phosphate (δ 18O P) range from 20.9 to 23.5‰ for the KZN sharks. For most species the range in measured δ 18O P values is about 0.6‰, but it may be as high as 1.1‰ for different teeth from a single shark. Dentine and enameloid within individual teeth have no apparent differences in δ 18O P values. The δ 18O P values of the KZN shark teeth reflect the typical habitat of the studied species, primarily the thermal structure of the water column off KZN at depths between 20 and 280 m. The δ 18O P values of teeth from different Greenland sharks from VB and Pacific sleeper sharks from PWS are very homogeneous, averaging 25.8 and 24.7‰, respectively. These values appear to be in equilibrium with deep (>500 m) ocean waters in each case at temperatures of about −0.3°C or less. There is little discernable evidence for species-specific fractionation effects for the oxygen isotope composition of phosphate in the studied marine fish. The oxygen isotope composition of carbonate in apatite averages about 9.1‰ higher than corresponding δ 18O P values, in agreement with equilibrium fractionation between carbonate and phosphate, but with a large variance (1σ = ±1.5‰). δ 18O C values also vary by up to 1‰ between enameloid and dentine within single teeth, but in a non-systematic way. Differences in δ 13C values between carbonate in enameloid and dentine is also large (up to 8‰) but the δ 13C values vary systematically. Enameloid is always enriched in 13C compared to dentine and the 13C content increases with developmental stage of the teeth. δ 13C values measured for enameloid (1.6 to 4.8‰) appear to approach equilibrium with dissolved inorganic carbon in seawater. In contrast, δ 13C values for dentine range from −6.4 to −2.3‰ for KZN sharks, and −9.0 to −10.8‰ for the cold-water sleeper sharks, and are compatible with a predominantly dietary carbon source. The 87Sr/ 86Sr ratios of teeth from KZN sharks as well as those from PWS and VB are uniform, averaging 0.709167. Sr content varies from 1270 to 2100 ppm, a range that is similar to that in well preserved fossilized teeth. Seawater Sr is thus clearly incorporated in vivo. Concentrations of Sm and Nd are in the ppb range and contrast the ppm range in fossilized teeth, indicating a postmortem incorporation of rare earth elements in apatite of the teeth.

New Host and Ocean Records for the Copepod Ommatokoita elongata (Siphonostomatoida: Lernaeopodidae), a Parasite of the Eyes of Sleeper Sharks

Seven of 8 Pacific sleeper sharks (Somniosus pacificus Bigelow and Schroeder, 1944) captured in Prince William Sound, Alaska, were actively infected, and all 8 had been at one time infected with the parasitic copepod Ommatokoita elongata (Grant, 1827) (Siphonostomatoida: Lernaeopodidae). Active infections consisted of adult females and chalimus larvae that had attached to the corneas of the sharks' eyes. This report documents a new host record and possibly the only reliable record of this parasite from a host other than the Greenland shark, Somniosus microcephalus (Bloch and Schneider, 1801). It also documents the first time O. elongata has been identified outside of the Atlantic Ocean or its locally adjacent straits and seas.

Ocular lesions associated with attachment of the parasitic copepod Ommatokoita elongata (Grant) to corneas of Greenland sharks, Somniosus microcephalus (Bloch & Schneider)

The eyes from six Greenland sharks, Somniosus microcephalus (Bloch & Schneider), infected with the parasitic copepod Ommatokoita elongata (Grant) were collected in the Arctic waters of Victor Bay, North‐west Territories, Canada, for study. Transformed adult female copepods, one per eye, were firmly attached to the corneas by an anchoring structure (i.e. the bulla) and each bulla was associated with an opaque area on the cornea. Two eyes additionally had one O. elongata copepodid attached to the cornea via frontal filaments with bullas which were each associated with a small corneal opacity. In addition to opacities associated with copepods at the time of collection, there were several randomly distributed, small, round‐to‐irregular, full‐thickness corneal opacities which were not associated with copepods. Two unfixed eye lenses grossly examined in the field were normal in appearance. Histologically, corneal epithelial ulceration and heterophilic keratitis, disruption, mineralization, and detachment of Bowman's membrane, thinning, disorganization, mineralization and fibrosis of the corneal substantia propria, and focal thinning and mineralization of Descement's membrane were observed. Mild heterophilic and mononuclear anterior uveitis was also present. Based on the present observations, it is concluded that parasitism by O. elongata could lead to severe vision impairment (possibly including blindness) in Greenland sharks. However, the otherwise healthy appearance of the infected sharks studied and the information contained in the literature suggests that O. elongata infections do not significantly debilitate the hosts.

A Greenland Shark from the Wreck of the SSCentral Americaat 2,200 Meters

Abstract The three-masted, wooden-hulled steamship Central America sank in 1857 during a hurricane 370 km east of Savannah, Georgia. During a recovery project begun in 1988, the unmanned research submersible Nemo equipped with video and still cameras filmed a 6-m-long, male Greenland shark Somniosus microcephalus at the 2,200-m-deep wreck site. The depth is 1,000 m deeper than the maximum reported depth for this species. The Savannah location is 440 km further south than the previously known North Carolina records for the Greenland shark.

Poisonings from flesh of the Greenland shark Somniosus microcephalus may be due to trimethylamine

U. Anthoni, C. Christophersen, L. Gram, N. H. Nielsen and P. Nielsen. Poisonings from flesh of the Greenland shark Somniosus microcephalus may be due to trimethylamine. Toxicon 29, 1205–1212, 1991.—The flesh of the Greenland shark, Somniosus microcephalus, especially in fresh condition, is toxic to both dog and man. Analysis of the toxic fractions indicates the presence of large amounts of trimethylamine oxide (TMAO) but no other substances that could be directly responsible for the poisoning. The symptoms appear to be due to an acute trimethylamine (TMA) poisoning arising from intestinal reduction of TMAO to TMA. TMA stimulates contraction of the guinea-pig ileum (antagonized by atropine but not hexamethonium). Low concentrations of TMA increase contraction of the rat phrenic nerve-diaphragm preparation, whereas higher concentrations cause blockade.

Evolutionary studies on pancreatic colipase

In this evolutionary study the following criteria have been used to prove the existence of colipase: 1. It restores the activity of human and porcine pancreatic lipase inhibited by bile salt. 2. It cross-reacts with antisera to human and porcine colipases. 3. Its restoration of lipase activity, inhibited by bile salt, in the tributyrin assay system, is prevented by antiserum to colipase. 4. It is a heat-stable, low-molecular-weight protein (molecular weight about 10 000 by gel-filtration). The occurrence of colipase has been verified in the exocrine pancreatic cells from hagfish ( Myxine glutinosa), ratfish ( Chimaera monstrosa), rayfish ( Raja radiata), Greenland shark ( Somnius microcephalus) and dogfish ( Squalus acanthius). No colipase activity could be found in the gastric juice of crayfish ( Pacifastacus leniusculus). These results indicate that colipase envolved in the vertebrates before the organized exocrine pancreatic gland and occurred simultaneously with the bile salts/bile alcohols.

Glycosidases in lymphomyeloid (hematopoietic) tissues of elasmobranch fish

Abstract 1. 1. High lysozyme and chitinase activities were found in Leydig's organ of Etmopterus spinax, Somniosus microcephalus and Torpedo nobiliana, in Leydig's and epigonal organs and spleen of Raja radiata, and in the epigonal organ of Rhinoptera bonasus. 2. 2. Strong chitinase activity with little or no lysozyme activity was noted in Leydig's and epigonal organs of Scyliorhinus canicula, and in the epigonal organ of Ginglymostoma cirratum and Heterodontus francisci. 3. 3. Very high β-N-acetylglucosaminidase activity was found in lymphomyeloid organs of all species investigated, and in the pancreas of Somniosus microcephalus. 4. 4. Thirteen other glycosidases were assayed in lymphomyeloid and digestive tissues of Ginglymostoma cirratum, Heterodontus francisci and Etmopterus spinax. Activities of α- d -mannosidase, β- d -galactosidase, β- d -N- acetylgalactosaminidase , β- d -glucuronidase and α- and β- d -glucosidase usually were higher in lymphomyeloid tissues than in digestive tissues.

Stimulation of immune reactivity by methoxy-substituted glycerol ethers incorporated into the feed.

In mice, the plaque-forming cell response to sheep red blood cells was stimulated by a mixture of methoxy-substituted glycerol ethers isolated from Greenland shark liver oil and by synthetic 1-0-(2-methoxyhexadecyl)-glycerol, given in the diet. In preliminary experiments, this synthetic compound also increased the ability of parental spleen cells to induce graft-vs.-host reactions in F1 hybrid mice. Glycerol ethers occur in the bone marrow fat of mammals and in the membrane phospholipids. It is postulated that the methoxy-substituted glycerol ethers supplied in the diet may stimulate the bone marrow and/or may be incorporated into membrane lipids, thereby changing the structure and function of the membranes.