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Icefish Cruise Summary
12 July 2004
H. William Detrich, Chief Scientist

Here I present highlights of the cruise accomplishments of various groups. Two important, but difficult to measure, benefits of the ICEFISH Cruise have been: 1) the intermingling of a very diverse group of polar biologists; and 2) the recognition and establishment of cross-disciplinary and international collaborations among the scientists. Many animated discussions have occurred, stimulated in part by a scientific lecture series (nine by the end of the cruise) that has been conducted during transits between island groups.
I think it is fair to conclude that the ICEFISH 2004 Cruise has been a major success. Photo of ICEFISH Scientists

I and my colleagues wish to express our heartfelt gratitude to the Captain and crew of the RVIB Nathaniel B. Palmer and the personnel of Raytheon Polar Services Company. Their exemplary assistance has enabled us to turn our scientific objectives into reality. It has been a true pleasure to work with these talented and enthusiastic individuals who have also become close friends.

Biochemical, Molecular, and Physiological Studies
Chief Scientist Detrich and graduate student Cate Cornell (Northeastern University) have prepared very high molecular weight DNA samples (>150 kilobase pairs) from 18 species of Sub-Antarctic notothenioids for use in genome-level studies of the genetic program of red blood cell formation in red-blooded species and for understanding the evolutionary mechanism of the programs loss by the white-blooded icefishes. Detrich also collected whole specimens of 16 notothenioid species for the gyotaku art program of Boshu Nagase, which is sponsored by CCAMLR.
Dr. Eric Anderson and Lukhanyiso Vumazonke (South African Institute of Aquatic Biodiversity) completed sampling of notothenioid species for taxonomic and population genetic studies. Anderson and Dr. David Stein (NMFS, NOAA) will study the deep-sea ophidioid Holomycteronus sp. obtained from the Falklands and will analyze four new records of fishes from Tristan da Cunha.
Drs. Guido di Prisco and Ennio Cocca (Consiglio Nazionale delle Richerche, Naples, Italy) have been characterizing the hemoglobins of 32 Sub-Antarctic notothenioids, the results of which will be integrated with their work on polar and temperate fish species ranging from the Antarctic to the Arctic. Cocca has purified DNA from many of the fish specimens for studies of their globin gene complexes. Seven ray species have also been sampled for studies of hemoglobin function and molecular phylogenetic analysis.
Dr. Joseph Eastman (Ohio University) collected and fixed large samples of the bovichtids Cottoperca gobio (Falklands) and Bovichtus diacanthus (Tristan), the eleginopid Eleginops maclovinus (Falklands), and four species of the non-Antarctic nototheniid genus Patagonotothen. He will use these phylogenetically basal species to formulate hypotheses regarding the diversification of the derived high-latitude Antarctic clade.
Dr. Romolo Fochetti (Universita degli Studi di Vitterbo, Italy) has sampled the lymphomyeloid organs (spleen, thymus, head kidney, etc.) from 30 notothenioid species for molecular studies of their immune systems.
Dr. Carl Hansen (Bloomsburg University, PA) has obtained tissues from 37 species of fishes for RNA, DNA, and protein extraction. This material will be used to study the G-protein signaling systems of the notothenioids, an important subject that has never been examined in fishes from the Southern Ocean.
Jacob Kendrick and Zachary Marion (University of Tennessee, Knoxville) have collected tissues for use in molecular-phylogenetic studies by the lab of Dr. Thomas Near (UTK). They have also collected morphometric data on the gape width and jaw protrusion of notothenioid fishes. More than 100 specimens of Sub-Antarctic notothenioids have been preserved for the University of Tennessee fish collection.
Drs. Guillaume Lecointre (Museum national dHistoire naturelle, Paris) and Federico Mazzei (Universita degli Studi di Genova) have generated chromosome preparations from 21 different fish species (106 total specimens) for karyotype analysis. The karyotypes of five basal notothenioids collected on this cruise have not been analyzed previously, so the work of Lecointre and Mazzei will contribute importantly to our understanding of chromosomal evolution of notothenioid genomes. They will also use very high molecular weight DNA and fiber FISH (fluorescence in situ hybridization) to establish gene order as a macrostructural genomic character for phylogenetic analysis of the notothenioids.
Dr. John Macdonald (University of Auckland, New Zealand) has recorded miniature end plate currents (MEPCs) from the Sub-Antarctic notothenioids for comparison to those of high-latitude species. He has made a total of 2,454 separate recordings from five species, with the best recordings coming from Notothenia rossii. Macdonald will analyze his data to determine whether the apparent cold-compensation of MEPCs from high-latitude Antarctic species (shorter than expected duration) is truly adaptive or rather a phylogenetically persistent trait that also occurs in the Sub-Antarctic notothenioids.
Dr. Anthony North (British Antarctic Survey, Cambridge, United Kingdom) focused on collecting muscle tissue: 1) from C. gunnari, Notothenia rossii, and Gobionotothen gibberifrons to use in studies analyzing circumpolar gene flow and local variability; and 2) from the Sub-Antarctic notothenioids B. diacanthus, C. gobio, and Lepidonotothen squamifrons to contribute to a phylogenetic study of the growth and development of notothenioid muscle cell size and cell number.
Dr. Bruce Sidell (University of Maine, Orono) extended his survey of myoglobin expression in notothenioid fishes, including 13 species that have not yet been examined. In collaboration with Joseph Eastman, he produced vascular fills of 17 specimens representing seven species and five families of notothenioid fishes for quantitation of vascular densities of retinal tissues. Hematocrits, retinal mitochondrial densities, and retinal vascular densities will be compared across notothenioid families to test hypotheses regarding the adaptational evolution of the cardiovascular system of this group.
To compare the kinematics of labriform swimming of the notothenioids to that of temperate species, graduate students Phil Ross and Shane Windsor (University of Auckland, New Zealand) collected more than 60 hours of video footage of the swimming of 48 individual fish from 14 notothenioid species. The video data has been digitized and is being analyzed to extract the relevant kinematic parameters.
Graduate student Steven Young (University of Birmingham, United Kingdom) collected heart and liver samples from 25 species for studies on adrenergic receptors and their expression profiles. He also prepared 29 vascular corrosion casts from eight notothenioid species for analysis of the three-dimensional topology of their vascular systems.

Ecological and Population Genetic Studies
Dr. Christopher Jones (US AMLR Program) has worked on the species composition, spatial distribution, food preferences, and population dynamics of the notothenioid fishes at each island group. He has observed a substantial change in the species compositions of the islands and will continue to analyze his data in the context of habitat classification.
Graduate student Kristen Kuhn (Univ. of Delaware College of Marine Studies) collected tissue samples from the Patagonian toothfish Dissostichus eleginoides and the mackerel icefish Champsocephalus gunnari for pilot population genetic studies.
Dr. Craig Marshall (University of Otago, New Zealand) collected 430 tissue samples from 16 notothenioid species. For 12 species the sample size is sufficient to permit genetic comparisons of population structure as a function of sampling location.
In an abyssal trawl (5,400 meters, 15 June) in the South Sandwich Trench, Dr. David Stein (NMFS, NOAA) obtained seven specimens of the grenadier, Coryphae-noides filicauda, which extends its depth range by 400 meters. This may also be the first recorded collection of the species within this CCAMLR region. The deep trawl also included substantial numbers of invertebrates, including eleven species of holothuroideans, several crustaceans, asteroids, anemones, octopods, and representatives of other abyssal taxa of interest to the benthic and invertebrate biologists aboard the NBP. Three other unidentified, juvenile Coryphaenoides were collected near Bristol Island at depths between 90 and 360 meters.
Drs. Marino Vacchi (Universita degli Studi di Genova) and Richard Eakins (University of New England) explored the sexual dimorphism of the South Georgian plunderfish Artedidraco mirus. Stomach contents of A. mirus and of B. diacanthus from Tristan were taken to study the feeding ecology of these small notothenioids.

Invertebrate Studies
Dr. Christoph Held and graduate student Florian Leese (University of Bochum, Germany) have collected more than 13,000 specimens of crustaceans during the cruise, among which there appears to be one probable new species of isopod. They have prepared DNA from many of these specimens for future studies of the phylogenetic relationships of Sub-Antarctic species to those of the High Antarctic and of the population structure of species from distinct locations. Six hundred of the specimens came from Tristan sampling.
Dr. Stacy Kim and graduate student Andrew Thurber (Moss Landing Marine Laboratories) have obtained quantitative Smith MacIntyre bottom grabs (22) from the island groups, including eight from Bouvetoya, six from the South Sanwiches, four from South Georgia, and three from Tristan da Cunha. These will permit a detailed comparison of the invertebrate megafaunal communities from each island group in relation to habitat classification. Furthermore, they studied the invertebrate bycatch from the bottom trawls, which provide will provide selective, but directly comparable, partial community descriptions. The video imagery from multiple ROV deployments will also be used to extract quantitative descriptions of the invertebrate communities of Bouvetoya and Tristan da Cunha.
At Tristan da Cunha, Dr. Susanne Lockhart (California Academy of Sciences) discovered an urchin, Stereocidaris sp., near Nightingale Island that represents the first cidaroid to be recorded from this region. Thus, it will serve as a key outgroup species for elucidating the phylogeny of the Antarctic cidaroids. In addition, the tidepool expedition at Tristan yielded many specimens of the endemic urchin, Arbacia crassispina, not collected since the Challenger expedition of the late 1800s. These specimens, together with Arbacia dufresnii collected from the Falkland Islands earlier in the cruise, represent key species and locales essential for an investigation of the phylogeography of this genus worldwide. Similarly, specimens of the genus Sterechinus, collected from Tristan da Cunha and all other island groups visited, will provide a substantial molecular dataset from which the stability of the five originally described species of this genus can finally be assessed.

Acoustic Seafloor and Habitat Classification
Graduate student Daniel Doolittle (University of Miami) has collected approximately 65 GB of single beam and multi-beam acoustic data. From this raw data set, acoustic records from the 6 banks/island groups (Burdwood Banks, Falklands, S. Georgia, S. Sandwiches, Bouvet, Tristan) have been extracted and are undergoing statistical clustering analysis. Each cluster represents a different seafloor type (sand, mud, rock, basalt, etc) and will result in a habitat map for each island area. Sixty-seven discreet sediment samples have been obtained from Smith MacIntyre grabs for ground truthing and other lab analysis. Doolittle is also examining whether viable phytoplankton in the sediment can recruit to the water column via resuspension, a process that would establish sediments as potential overwintering refugia.

Museum Collections
Anderson, Eastman, Kendrick, Lecointre, Marion, Stein, and Vumazonke have prepared many specimens that will be curated by museums and universities throughout the world, including the Museum national dHistoire naturelle (Paris, France), the Smithsonians Museum of Natural History, the South African Institute of Aquatic Biodiversity, and the University of Tennessee, Knoxville. These valuable specimens will be available for study by all qualified biologists.

Fishing Tristan da Cunha
12 July 2004
R/V Nathaniel B. Palmer
Bill Detrich, Chief Scientist

We completed sampling activities around Tristan da Cunha Island on 11 July, and are currently in transit to Cape Town, South Africa. During the past week, we occupied a total of eleven stations and two shore-based sampling sites and deployed gear on 32 occasions. Sampling depths during the past week have ranged from tidepools to 1042 meters. These deployments included dipnet collecting, hook and line, two otter trawls, two Blake trawls, 21 Smith MacIntyre grabs, and seven ROV deployments.
The total collection of finfish specimens obtained during the ICEFISH cruise through joint BMP/EPG (biochemical, molecular and physiological/ecological and population genetics) trawl deployments was 9983 specimens of 61 species. Finfish captured and characterized during the past week at Tristan da Cunha included a total of 1231 specimens of 8 species. Photo of Tidepooling at Tristan The fish included Echiodon cryomargarites (1), Helicolenus mouchezi (48), Lepidoperca coatsii (110), Notopogon lilliei (4), Schedophilus sp. cf. ovalis (1), Sebastes capensis (4), and five specimens of fish in the family Callionymidae that we were unable to identify to genus or species. The tidepool dipnet collections yielded 102 specimens of the klipfish Bovichtus diacanthus, the primary nototheniod target species of ICEFISH at Tristan da Cunha.

Fishing Bouvetoya Island
30 June 2004
R/V Nathaniel B. Palmer
Bill Detrich, Chief Scientist

Photo of Grim Bouvetoya The composition of the fish and invertebrate fauna of Bouvetoya Island are quite different from anything that weve seen before. Dr. Christopher Jones (US AMLR Program) reports that the species with the highest density observed around Bouvetoya has been L. larseni, consistent with other island groups within the Antarctic convergence. However, there has been a substantial change in the species composition relative to the South Sandwich Islands and South Georgia, with strikingly lower species diversity and abundance of finfish species. Furthermore, several of the species that demonstrated the highest densities at other island groups, such as L. nudifrons and G. gibberifrons, have been altogether absent in catches around Bouvetoya. We have also observed considerably higher numbers of L. squamifrons, and Macruourus spp. in the species inventory. One grenadier species (Macrourus holotrachys) is by far the most numerically abundant fish species below 400 meters, a situation that must have derived from successful founder populations that arrived from the South Sandwich area.
Our most successful trap fishing occurred at Bouvetoya with twenty-eight specimens of N. coriiceps being captured in two sets of three traps each at 50 meters depth. Photo of Bounty of Coriiceps One of the trap specimens appears to be a new length record for N. coriiceps (65 cm total length, 59.5 cm standard length, 3.38 kg). The previous record was 62 cm TL.
The ROV was deployed at a site that in prior trawls had produced a very high yield of polychaete tube worms. Dr. Stacy Kim reports that quantitative assessment of the video of the undisturbed reef and cross-comparison to the trawl specimens will produce the most complete invertebrate community dataset yet obtained on the cruise. Video of a number of C. aceratus brooding egg clutches was also obtained, which indicates that C. aceratus uses a nest guarding strategy. Previously, nest guarding has been observed only for male Harpagifer antarcticus and male Lepidonotothen nudifrons; this is the first evidence of channichthyid nest guarding.

A Unique Opportunity
Research On Board the RV/Nathaniel B. Palmer
Icefish Cruise 2004

Photo of Cidaroid Brooding Young Drs. Susanne Lockhart (ICEFISH participant) and Rich Mooi of the California Academy of Sciences, with Dr. John Pearse (Professor Emeritus) of the University of California, Santa Cruz, are studying a curious parasite, Echinophyces mirabilis Mortensen 1909, that is known to infect three species of Antarctic cidaroid sea urchins. The parasite produces the drastic effect of turning the reproductive system of the urchin host upside down. In all sea urchins the gonoduct extends from the gonad up to the gonopores at the top of the urchin. In infected urchins this gonoduct is present but atrophied and no gonopores exist on the genital plates. Instead, another, functional, gonoduct extends, in the female, from the gonads down to gonopores around the mouth. What makes this dramatic result of infestation even more fascinating is that these cidaroid urchins brood their young around the mouth. Perhaps the term parasite then is an inappropriate one, as the precarious transfer of embryos from the usual gonopore position all the way down the test to the mouth is eliminated. Instead, they are released directly into the brood protecting region. In males the functional gonoduct connects to gonopores positioned half way down the test. Infestation can also cause other abnormalities of the test, spines and other external appendages. These changes can be of such magnitude that an infected species can be mistaken for another species altogether. When originally described, E. mirabilis was tentatively considered to be related to the Fungi. However, its true taxonomic standing, even to the level of Kingdom remains unclear. The only parts of the organism clearly visible are tubules protruding from the thorns on the primary spines. The 18S ribosomal RNA gene of E. mirabilis will be sequenced in order to elucidate its taxonomic affiliations. A combination of other molecular techniques and histological methods will be used to further understand the fascinating effects of infestation. Known only from Antarctic waters, once better understood, E. mirabilis promises to provide valuable insights into how host-parasite interactions can affect speciation and distributions of organisms. The ICEFISH cruise presents a unique opportunity to study these organisms in the Sub-Antarctic. Infestation has been recorded in the region of the Antarctic Peninsula and the Ross Sea and appears to be more common in the former region. E. mirabilis probably has a circumpolar distribution. However, the full extent of the range of this parasite and frequency of infestation is unknown.

Icefish Cruise Update
21 June 2004
Bill Detrich, Chief Scientist

We are currently enroute to Bouvetoya Island and expect to arrive there at 0700 local on 23 June. (Click on the image below for a larger map of their location) Cruise Track Map 6-21-04
This was an eventful week. A total of 3,812 specimens of 13 species were captured and characterized. The South Sandwich Island stations have demonstrated the highest densities of finfish (dominated by L. larseni and G. gibberifrons) thus far of any of the island groups sampled by ICEFISH. The abyssal trawl of 15 June (5,400 m) on the east side of the South Sandwich Trench produced seven specimens of the grenadier, C. filicauda, which extends its depth range by 400 meters. This may also be the first recorded collection of the species within this CCAMLR region. The deep trawl also included substantial numbers of invertebrates, including eleven species of holothuroideans, several crustaceans, asteroids, anemones, octopods, and representatives of other abyssal taxa of interest to the benthic and invertebrate biologists aboard the NBP. Three other unidentified, juvenile Coryphaenoides were collected near Bristol Island at depths between 90 and 360 meters. Analyzing these specimens will likely contribute to a better understanding of the development of grenadiers. Also noteworthy was the discovery by Marino Vacchi (Universita degli Studi di Genova) and Rich Eakin (University of New England) that the spiny plunderfish species Harpagifer antarcticus, considered endemic to the Antarctic, also occurs as far north as South Georgia.
Sampling depths during the past week have ranged from 75 meters to 5,400 meters. We were unable to complete the stations planned for the southernmost island in the South Sandwich Island chain for several reasons. First, we experienced pack ice south of Montagu Island that slowed our progress and substantially increased fuel consumption. Second, gear deployments and sampling efforts at Bristol Island were hindered by pack ice and high winds. In one instance, this resulted in the loss of a Blake trawl when it became snagged on an iceflow during retrieval. Finally, low temperatures (18 C, with wind chill in excess of 40 C) resulted in the freezing of finfish specimens before they could be transferred to aquaria. This problem was partially mitigated by the use of a warm water wash over the cod end as nets were brought onto the deck. The frozen specimens were useful for tissue collection and for taxonomic studies, but some physiological experiments could not be performed due to the lack of live animals.

18 June 2004
59 South, 26.6 West

Photo of Sea Ice on 6-18

This map shows the current extent of the winter sea ice near Antarctica. Note the prominent finger of ice that reaches up into the South Sandwich Islands. We are curently trawling at Bristol Island, then will move to the southern-most three of the chain. (Click on the map for a larger image.)

17 June 2004
On board the R/V Nathaniel B. Palmer
South Sandwich

We are currently at Montagu Island, about halfway down the South Sandwich Island chain. Photo of Sea Ice Infrared Image We're in a bit of a blow right now, 40-50 knot winds, current temperature is -13.5 deg C with a wind chill of -42 deg C. Balmy! We're surveying for suitable bottom to trawl, but needless to say, there's no deck work permitted under these conditions. You can see on the sea ice map that the sea ice edge is very close to us. (ships track is in red.)

ICEFISH Cruise Report
14 June 2004
Bill Detrich, Chief Scientist

We have just finished our first day sampling the northern and eastern shelf areas of Zavodovski Island, at the northernmost end of the S. Sandwich Islands archipelago and are currently enroute to conduct a deepwater trawl in the South Sandwich Island trench.
Sampling depths this past week have ranged from 45 meters to 401 meters. There was one case of gear loss, which occurred at the northern Zavodovski Island Station. Here, it appears a large mass of volcanic rock filled the Blake trawls net and cod end, which caused a wire tension spike exceeding 12500 lbs. and the subsequent breaking of the trawl bridles. Further attempts at sampling this station gave similar levels of tension spikes, though in these cases the gear and catches were saved through the use of a weak link shackle on one bridle that is designed to separate at a critical level of wire tension.
As we near the midpoint of our cruise, we have made a number of significant discoveries. Photo of P. formosa At King Edward Point, David Stein (NOAA/NMFS Systematics Laboratory) made contact with and received specimens from a British Antarctic Survey biologist who is collaborating on a study of reproductive parasitism of the crab Paralomis formosa (shown at left) by snailfishes of the genus Careproctus. Christoph Held (University of Bochum, Germany), who studies this crab species, has been looking for specimens that contain snailfish eggs or larvae under the crabs carapace. The image below (left) shows the location of the snailfish egg mass. The eggs depress the gills of the crab and inhibit their function. Photo of Paralomis gills Photo of Snailfish eggs How the female introduces the eggs under the crabs carapace is one of many mysteries regarding this host/parasite interaction. Held has just found this set of snailfish eggs nearly ready to hatch. Stein will study these larvae to learn more about the life cycle of these poorly understood fishes. ( photos by David Stein)
As always, tissue specimens are being collected from fishes for use in experimentation on board and at the home institutions of the participants. Stein, Eric Anderson (South African Institute of Aquatic Biology), and Jacob Kendrick and Zachary Marion (University of Tennessee, Knoxville) continue to prepare voucher specimens for their museum collections. Christopher Jones (US AMLR Program) continues to map the population parameters of the notothenioid species as we survey the island groups above and below the Antarctic Convergence.
With our arrival at the South Sandwiches and our pending work at Bouvetoya Island, we are now entering the least studied and perhaps most interesting regions of the cruise.

9 June 2004
The R/V Nathaniel B. Palmer and crew are now on their way to Grytviken where they will spend a day at King Edwards Point, then continue South Georgia fishing before heading to the South Sandwiches. Their weather continues to be quite good. Photo of NOAA weather map Here is a report from Chief Scientist Bill Detrich of their successful fishing this first week in June:

As of June 7, 2004, we have completed a total of 35 Stations with 82 gear deployments. Sampling depths during the past week have ranged from 146 meters to 2710 meters. Most hauls have been successful, in part owing to the acquisition of a trawl fitted with roller ground tackle which has considerably reduced instances of gear damage. A total of 1869 specimens of 14 species were captured and characterized during the past week. The abyssal otter trawl (2710 meters) has been noteworthy for producing two fish specimens in particular, the first of which was a rare ophidioid of the genus Holcomycteronus (see report below) and the second fish was Coryphaenoides armatus, which is a representative of a common, world-wide species of deep-water grenadier.
Another discovery for this week was the capture of a specimen of the plunderfish Artedidraco mirus at Shag Rocks. Previously, this fish had only been found in the waters of South Georgia, so this finding represents a significant extension of the known range for the species. Rich Eakin will study this and other specimens of A. mirus at his home institution, The University of New England.
The trawls continue to be rich in benthic invertebrates, including pencil urchins (cidaroids), the urchin Sterechinus numayeri, various shells, tunicates, jellies, polychaete worms, basket stars, sea squirts, crabs, etc. The invertebrate biologists are seeing clear transitions in the invertebrate fauna compared to the Falkland Islands and the Burdwood Banks, with greater diversity at the Shag Rocks/South Georgia stations and an increase in the relative biomass of tunicates.
We are grateful to the Captain and crew of the R/V Nathaniel B. Palmer and the personnel of Raytheon Polar Services Company for their excellent work, which is so essential to our research.

4 June 2004
R/V Nathaniel B. Palmer
West of Shag Rocks

During an otter trawl tow at a depth of 2700 meters, about 200 nautical miles west of Shag Rocks, we collected a specimen of a cusk eel, Family Ophidiidae, in the genus Holcomycteronus. Photo of HBrucei Although its identification and a survey of the pertinent literature will not be complete until after the cruise, it is a significant find of a rare deep-sea fish. The only previous record of a member of this family from the Southern Ocean is of H. brucei, known from one individual collected in the Weddell Sea at 4500 m and described in 1906. If the new specimen proves to be conspecific it will be only the second known example of the species. If not, it will probably be a record of a previously unknown species from these waters. Photo of Eric Anderson Photo of David Stein The specimen is being studied by Eric Anderson (left) of the South African Institute of Aquatic Biology and David Stein (right) of NOAA/NMFS Systematics Laboratory.

1 June 2004
R/V Nathaniel B. Palmer
Off the Falkland Islands

Today we captured our first specimens of the icefish Champsocephalus esox. This species is critical to many of our studies, but we were not finding it in our bottom trawls. Finally, Chris Jones suggested "flying" our bottom trawl in the mid-water and we collected three specimens early this morning. Everyone was very excited, as well as greatly relieved. The Falkland Islands are the only location on our cruise where we expected to find C. esox.
We are now steaming for Shag Rocks and South Georgia. On the way we hope to find deep sites (2,000-4,000 meters) for trawls to obtain some abyssal fishes for study by David Stein and Eric Anderson.


May 30, 2004
The R/V Nathaniel B. Palmer and crew are now on their way to Shag Rocks and then on to South Georgia Island. Here are some of the things they saw and did before they left the Falkland Islands.

Stanley, the largest town in the Falklands, has approximately 2,000 residents. We were greeted warmly by the community, the Governor General Howard Pearce and his staff, and the personnel of the Fisheries Department of the FI during our port call of 28-29 May. Photo of Stanley, Falkland IslandsSeveral ICEFISH scientists gave presentations to the schoolchildren of Stanley, and we gave the students and VIPs guided tours of the R/V Nathaniel B. Palmer. Each student, as well as our other visitors, received an ICEFISH Cruise t-shirt. The t-shirts were very popular.

Photo of Lobster Krill During our trawls near the Falkland Islands at 70-100 meters depth, we have encountered an ecosystem dominated by the lobster krill Muneda, a type of shrimp (specimen length approximately 7 cm from posterior to extent of claws). Our nets are filled with many kilograms of these critters and little else. To find an ecosystem with so little biodiversity is a surprise to us.

Photo of P. tessellata Photo of P. squamicepsOther interesting specimens in our nets include Patagonotothen tessellata (left) and Patagonotothen squamiceps (right), a relatively rare Sub-Antarctic notothenioid. Both were captured near Stanley, FI.

This Falklands mullet, Eleginops maclovinus, Photo of Falklands Mullet is approximately 10 inches (25 cm) long. Like most notothenioids, this species sculls through the water using its pectoral fins Photo of S. Windsor video recording (side fins that are blurred due to slow camera shutter speed), rather than moving its tail. Shane Windsor at right is using video recording to study the mechanics of the mullets motion.

The mullet and most notothenioid fishes are red-blooded, whereas the sixteen species of "white-blooded" icefish (notothenioid family Channichthyidae) lack red blood cells. One of the adaptations that enables the icefishes to circulate sufficient oxygen to their tissues is a greatly expanded vascular system. By comparing vascular casts from red- and white-blooded notothenioids, Drs. Eastman and Sidell will test hypotheses regarding the evolution of the icefish vascular system. This work also has potential medical applications because it will contribute to our understanding of the factors that regulate the development of the circulatory system in all vertebrates, including humans.
Photo of Bruce and Joe Vascular Casting Here Drs. Joe Eastman (left) and Bruce Sidell (right) are preparing a Falklands mullet for a vascular cast. After washing the circulatory system to remove the blood, they inject a liquid latex that solidifies, thus producing a cast of the circulatory system. The fish will be frozen and shipped to Dr. Eastman's lab. There he will image the latex cast, which is opaque to X-rays. The result will be a three-dimensional reconstruction of the mullet's vascular system.

May 22, 2004
On board the R/V Nathaniel B. Palmer
Burdwood Banks
54 deg 32 min South, 55 deg 55 min West

We're now in our fifth day at sea on the extreme eastern end of the Burdwood Banks. We're setting fish traps in 500 meters of water and will shortly begin trawling the bottom. We've encountered some problems with our nets, which are being torn by the rough, rocky bottom. To prevent this, we've added chaffing gear to the nets as well as weak links that will break when the net encounters an obstruction.
So far we've caught many of our target species, and last night we collected our first Patagonian toothfish (Dissostichus eleginoides), which is commonly known as the Chilean sea bass and is served in restaurants in the U.S. We have on board Dr. Christopher Jones of NOAA, who represents the U.S. on the Committee for Conservation of Antarctic Marine Living Resources (CCAMLR). Dr. Jones studies the life history and the distribution of the toothfish to help manage the fishery effectively and to prevent over-exploitation.
Our trawls have been bringing up large amounts of bottom-dwelling (benthic) invertebrates. The team of invertebrate biologists on board are absolutely delighted by what the fishermen regard as "bycatch" (e.g., trash). They may have discovered a new invertebrate species, but further study will be required to determine if this is correct.

Bill Detrich
Professor of Biochemistry and Marine Biology
Dept. of Biology, Northeastern University