HICEAS 2010: Weekly Blog from NOAA Ship McArthur II
|Date ||NOAA Ship McArthur II|
| ||* USE SHIPTRACKER TO FOLLOW THE PROGRESS OF NOAA SHIP McARTHUR II *|
After a brief period of rest and re-provisioning in Honolulu, the HICEAS 2010 survey resumed 30 November on board NOAA Ship MCARTHUR II. Sean Hanser of Naval Facilities Engineering Command Pacific joins Leg 5, and Jeremy Rusin replaces Barb Taylor as Cruise Leader. Despite the enthusiasm of all on board to resume data collections and to make our way toward San Diego, the weather has been impeding both. At times, strong trade winds have only allowed us to reach speeds of 6 knots, and maximum speeds have struggled to reach 8 knots. Slogging slowly uphill at speeds too slow to survey had a negative impact on our strip transect seabird effort. Nevertheless, we found 17 birds of nine species comprising a satisfying mix of tropical and subtropical seabirds. Species such as Bonin Petrel and Northern Fulmar (our first for HICEAS 2010) reflects our progression from the sub-tropical waters around Hawaii to cooler sub-temperate waters to the northeast. Marine mammal survey efforts yielded a less satisfying two sightings: one of Risso’s dolphins and another of sperm whales. The acoustics team’s plan for around-the-clock recordings for the duration of the leg was disrupted as a result of heavy winds and high swells the night of 1 December when we were forced to pull the array in during a night-time stunt. Acoustics was out of business for the following two days due to continuing rough seas. During the one full day of effort we managed to detect one Minke whale and three sperm whales. Additional boings were heard throughout the whole day. Unfortunately, oceanography also could not escape the impacts of our poor weather, which forced us to turn off the TSG and limited our data collection. Despite this, we have seen a few changes as we exited the primary study area and entered the expansive abyssal plain that separates Hawaii from the mainland. There has been a drop in sea surface temperature from its average of around 26 deg C to the mid 23 deg C. There has also been a dramatic drop in mixed layer depths from averaging between 55-65m now down to between 85-95m. All fingers and toes are crossed for improved weather next week, the final week of HICEAS 2010.
|29 NOVEMBER||Leg 4 Report to be posted shortly|
|21 NOVEMBER||This week we traded the trade winds for the pineapple express. Bad trade. The pineapple express is the winter weather system that sends low pressure systems slinging from Hawaii towards the North American coast. In actuality, Japan deserves the credit for generating this string of lows that resulted in such high sea states that the Navy told us to skedaddle all the way down to 20º north…twice! As a result we spent much of the week either running away or slogging our way back northwards. We did manage to keep most of the oceanography going and found within a period of three days, sea surface temperatures dropped from 27.2°C to as low as 23.1°C. These temperatures represent some of the lowest that we have seen so far on the cruise. |
The birders (Michael Force and Sophie Webb) managed to keep observing and get the story of the week. In slightly over one hour, one to two nautical miles south of Sand Island, Midway, they saw more Laysan Albatrosses than all species added together for the entire HICEAS 2010 survey. They conservatively estimated 30,000 to 50,000 Laysan as well as maybe 20,000 Bonin Petrels and 3000 Black-footed Albatrosses. To be honest, it is almost impossible to estimate bird aggregations of this magnitude. Needless to say, the past couple of days were hectic trying to keep up with albatrosses streaming through the 300 meter survey zone. Despite some rather slow days, they tallied 1653 birds of 24 species, with a daily average of nine species. A mallard was clearly out of place and the first of this species for HICEAS 2010.
On the five days acoustics could deploy the array they detected seven sperm whale groups, two unidentified dolphin schools and one Minke whale. Possible 'boings' of Minke whales were heard on all except one day. The mammal team also had few detections and few opportunities for photography or biopsy.
The duration of this leg is headed south and east along the northwest chain of reefs and islets. We’re all hoping for improved weather as we wrap up the tracklines for HICEAS 2010.
Black-footed Albatross (L); Photo: Jim Cotton; Black-footed and Laysan Albatross (R); Photo: Sophie Webb.
Week 2 of leg 4 of HICEAS has several interesting sightings. False killer whales are known to have groups that can be spread over miles, but this group took the area of a group to a new record: it stretched over 19 miles! This hunting behavior allows this predator of large fish to find their prey in a desert sprinkled lightly with little oases of productivity. This was just such a spot. On this day, there was an out of the ordinary drop in both sea surface temperatures (down 2ºC) as well as salinity (down .8 PSU). These conditions were paired with a significantly shallower mixed layer depth (~45m), a pattern noticed to correlate with mammal diversity and density throughout the study. The visual and acoustic teams worked together to find the little pockets of 2 to 3 individuals. We got photos and biopsies of this most remote group of false killer whales in HICEAS.
We had a lovely evening sighting of another patch of productivity. The sea was literally boiling with small fishes being chased from below by tuna and by birds from above and by a gulping Bryde’s whale in between. A whale shark was also part of the scene. Many of the birds were Wedge-tailed Shearwaters, a common local breeder. Of 3,142 seabirds tallied this week 2,440 were this species. Diversity is diminishing as the number of migrants decline with 22 species this week. Birders were treated to a surprising 60 sightings of a strikingly marked visitor from the southwest Pacific: the White-necked Petrel.
After all the troubleshooting during the first week of leg 4 the acoustics team was back in the race. They totaled 13 acoustic detections this week including eight groups of sperm whales and five schools of delphinids - false killer whales, Risso’s dolphins, rough-toothed dolphin and two unidentified dolphin schools.
The oddity of the week was finding this curious piece of something-that-formerly-flew. Candidates for its former identity (before becoming a remote floating aquarium in the middle of nowhere for some tropical fish) are: airplane fuselage, engine cowling and piece of a rocket. The latter has the winning vote so far.
At week’s end we had to run south to avoid a nasty storm that was promising 30 foot seas at Midway. The storm may keep us south of the study area for several more days, but we are making the best use of our time and surveying new seas.
False killer whale, Pseudorca crassidens, with NOAA Ship McArthur II in background.
Mysterious piece of "something-that-formerly-flew" encountered at-sea.
|07 NOVEMBER||The last leg of HICEAS 2010 in Hawaiian waters started with continued high winds off Maui on October 29. The winds and seas calmed for our events of the week on Halloween: another sighting of Longman’s beaked whale (Indopacetus pacificus) and an invasion of ghouls, witches, sea sprites and hillbillies. The beaked whales ran away from our frightening visages and remain a species unwilling to give samples to science. The acoustic team managed to place a BURP in their projected path but they also were silent for science.|
The acousticians started this leg re-splicing the array onto the lead-in cable due to a crack and water intrusion in the previous splice. Once acoustic effort was resumed, they detected two sperm and one beaked whale group.
All systems are full ahead for oceanography.
The birders found 27 species this week. As the season changes we were treated to tens of thousands of Short-tailed Shearwaters heading south. Quite unexpected were two disoriented juvenile African Silverbills (a Hawaiian exotic native to Africa) that came aboard about 100 nautical miles south of Ka’ula. As we progressed farther northwest, we found an increasing number of Black-footed Albatross.
The last 3 days of the week had almost no effort due to thirteen foot swells and high winds. By days end on Friday seas has started to calm and we closed with a nice school of Fraser’s dolphin. We look forward to calmer weather and better stories next week.
A group of Longman's beaked whales avoiding the frightening group.
|27 OCTOBER||The third full report from the HICEAS survey has been posted on the web. Please visit the Reports from Sea link in the menu on the left to access the report. |
Papahānaumokuākea Monument - perhaps an unfortunate name for this splendid place. We have been sailing in the Monument waters for almost 3 weeks now and everyone on the ship refers to this place numerous times a day but no one can pronounce or even spell Papahānaumokuākea, so no one does. Instead, the P word has been replaced by a more accessible ‘the’ and for all of us on board this place will always be fondly remembered as ‘the Monument’.
We completed our 20-day tour of the Monument early in the morning on 23 Oct, with a continued run of excellent weather and relatively few animals. Previously, short-finned pilot whales had resisted our best efforts to obtain biopsies but a few donors stepped up this week. And when several individuals from one group spyhopped (lifted their heads straight out of the water) as the ship passed by, we could see that they had perfectly flat heads, like they had all swam into a wall at high speed. These are quite different from the rounded heads (Globicephala!) we are familiar with from the eastern Pacific, and we have to wonder if these two forms might also be acoustically distinguishable. These kinds of distinctions are potentially important for identifying stock boundaries or possibly even taxonomic differences (species or subspecies) among the whales and dolphins out here – just the kinds of issues we are here to investigate with our surveys and sampling
The Oceanography Department (Justin) was happy to report that there were no sensor or instrument malfunctions and few-to-no errors in our TSG or CTD systems. The acousticians logged 47 hours of standard effort and 18 hours of ‘acoustic chase’, with beaked whales accounting for 37% of our 38 acoustic detections this week. They also detected 2 false killer whale groups that were later visually sighted and another probable detection. Other acoustic highlights included pilot whales (4) and Risso’s dolphin (1). Not to be out-clicked, our on-board paparazzi this week photo-documented 15 sightings, with 1126 exposures of six species, with pilot whales receiving top coverage. The biopsy team sampled 4 different species including false killer whales near Nihoa and one obliging Bryde's whale (Cotton photo below, top). The birders found 29 species this week (including four species of storm-petrels) with high numbers of Wedge-tailed Shearwaters and Brown Noddies around Nihoa. They also documented the arrival of Tristram’s Storm-Petrel at its Nihoa nesting colonies: there were hundreds this week compared to less than five on previous transits.
This is the end of our last full week at sea this leg as we begin our downhill slide into Maui. A buzz is building around the ship as people anticipate getting off these steel decks for a few days ashore. Our thanks to Capt. Greg Hubner and the fine crew and officers of the McArthur II for their exceptional hospitality and support of our efforts out here – it’s been great sailing with all of you! (Bob Pitman with contributions from Tina Yack, Mike Force, Sophie Webb, Justin Garver, Jim Cotton and Suzanne Yin).
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Bryde's whale, Balaenoptera edeni. Photo: J. Cotton
Sunrise at Necker Island. Photo: J. Cotton
We enjoyed surprisingly good weather this week as we worked our way east along the north side of the banks and atolls of the Papahanaumokuakea Monument, following the 1000 ftm isobath. We had a number of bank failures though – we kept expecting to see some cetacean evidence of the vaunted ‘island effect’ (increased productivity around islands), but even on good days we still only managed a handful of mammal sightings. We did, however, record our first sperm whales of the leg. Sperm whales are a special challenge for our abundance surveys - they are difficult to census because they dive deep and can stay underwater for 1.5-2 h. They are supremely adapted for deep diving but only because they have the single worst anatomical feature that a deep-diver could possibly own - lungs. Their food and their air supply are miles apart and they have to make the long commute numerous times daily to access both – not a very intelligent design. We therefore spend 60 min with most of our sperm whale sightings to obtain better school size estimates and to see how those estimates change with time. We also recorded our first minke whale and Fraser’s dolphins of the trip (see photo by C. Oedekoven below); both narrowly avoided making donations to our biopsy holdings.
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Group of Fraser's dolpins, Lagenorhyncus hosei. Photo: C. Oedekoven
|09 OCTOBER||Good weather continues to shine on us here as we work the NW Hawaiian islands but there have been few animals. We received coordinates for false killer whales (FKW) that were satellite tagged last week by our colleagues on the NOAA Ship Oscar Sette. The whales were less than 30 miles away so we spent most of a day trying to track them down but to no avail. We did however find our own small gaggle of FKWs during a transit we made out of the Monument to deploy our wet garbage this week. It was a group of 5 that kept circling in a small area and leaping out of the water (see Cotton photo, below, top). They had corralled a 3’ wahoo and were having fun keeping it at bay. Individuals in that group were very thin with ribs clearly showing (recheck that photo); no wonder they were so excited. The cookie-cutter shark is a small (12-18”) mesopelagic species that feeds at times by sneaking up behind cetaceans and gauging out ice cream scoop-sized bites of flesh and then dashing off. The whales and dolphins in these waters are often covered with healed wounds and fresh bites from these partial predators (see photo below, bltton of a Bryde’s whale), and many tons of cetacean flesh must be consumed this way in Hawaiian waters every year – one bite at a time. We collected 14 biopsy samples of our own (4 Balaentoptera edeni, 5 Steno bredanensis, 5 FKW). The first two weeks on Leg 3 have been running smoothly in terms of oceanography with daily operations running according to plan under Justin Garver’s constant vigilance. Repairs made by Candice Hall and Todd Walsh seem to have fixed our CTD problems from Leg 2, and an issue with our bow temperature sensor was repaired as of 10/8 thanks to ship’s ET Charlie Goertzen. XBT data has shown a mixed-layer change from 100-125m during the first few days of Leg 3, up to 20-60m in the past few days. This change has also been apparent in the ACBS data, which has recently been recording a much denser deep-scattering layer. It was an exciting week for acoustic eavesdropping with 45 detections during ~74 hrs of monitoring effort. Highlights included a beaked whale detection that we chased and sighted ~1.5 hrs later. We also heard several FKW subgroups on 7 Oct, which we tracked jointly with the visual team. Other detections included rough-toothed dolphins (3), Risso’s dolphins (2), pilot whales (5) and a Bryde’s whale on our evening sonobuoy. The birders had a run on birds, primarily Wedge-tailed Shearwaters—3129—75% of the total birds. The average daily species count was 17 - highest for the cruise, with a mix of local breeders and migrants. Among the 32 species recorded, was Blue Noddy, the first for the cruise, two Wilson’s Storm-Petrels, and a Flesh-footed Shearwater. We also picked up our first glass fishing float this week – it will be raffled off in the ship’s store with all proceeds going to the McArthur II Dockside Hydration Fund. (Contributions from Tina Yack, Mike Force, Sophie Webb, Justin Garver, Suzanne Yin, and Jim Cotton).|
False killer whale, Feresa attenuata. Photo: J. Cotton
Bryde's whale, Balaenoptera edeni, with various wounds from predators.
|02 OCTOBER ||The mighty MAC (II) left Honolulu on Sunday and headed south and east to do a series of survey lines south of the main Hawaiian Islands: spirits were high, the winds were low, but not many animals in this section of town. We completed a series of offshore legs south of the main Hawaiian Islands in good weather and next week we look forward to working in close to the northwest chain. There were 2 false killer whale sightings this last week and both consisted of single animals – they must have dropped out of school. Perhaps the best sighting was a group of pygmy killer whales, Feresa attenuata, on a seamount west of the big island. They were seemingly at home amid a tangle of longline fishing gear and several fishing boats also perched on the pinnacle. There were also several Grampus sightings, our first of the cruise – and at least one was excited about seeing us (J. Cotton photo attached). A relatively slow week for the biopsy crew, though we were able to add a new species to the Mac HICEAS biopsy list--with 3 samples from a reasonably accommodating group of pygmy killer whales. One sample from a bowriding false killer whale, was a very welcome addition to the -80 freezer.|
After 2 1/2 days of splicing and testing the acoustics team deployed the array on 29 Sept so we have eyes and ears on line now. They have had 11 acoustic detections; highlights including Grampus, Feresa, a sperm whale and a Mesoplodon sp. The birders reported 596 birds of 27 species recorded in the strip transect this week. About 75% were two species: Wedge-tailed Shearwater (282) and Pacific Golden-Plover (162), the latter a migrant shorebird. Other highlights include Christmas Shearwater and Tahiti Petrel, both firsts for the cruise. Besides counting birds, Sophie Webb has been beavering away at the cruise t-shirt – it is going to be another stunner; get your orders in early.
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Risso's dolphin (Grampus griseus); Photo: J. Cotton
HICEAS 2010 Logo; Artist: Sophie Webb
|24 SEPTEMBER||The second full report from the HICEAS survey has been posted on the web. Please visit the Reports from Sea link in the menu on the left to access the report. |
One of the goals of leg 2 was to cover all of the HICEAS transect lines in the far northwestern section of our study area before winds start picking up during the coming weeks. We’ve had cooperative weather this week, and today we are happy to report that we have completed our last line in this NW corner. Daily sightings have ranged from 1-2 earlier in the week to a high of 10. Species seen include Bryde’s whale, sperm whale, Mesoplodon and/or Ziphius beaked whales, striped dolphin, false killer whale, and short-finned pilot whale. Three false killer whale encounters provided excellent opportunities to evaluate and refine,with the help of Shannon Rankin and Jay Barlow on land, the combined acoustic/visual protocol for detecting false killer whales groups and estimating the total number of animals present. During one sighting, our combined acoustics and visual efforts resulted in the successful visual detection of all seven subgroups that were scattered across a few square miles. During a separate sighting, we successfully obtained 5 biopsy samples, which will contribute to our knowledge about the distribution and population structure of false killer whales in this area. Throughout the week, the days with the most sightings have corresponded to areas were the mixed layer was shallowest – changing from about 46m to 14m as sightings increased, and back to 30m as sightings decreased again. The 15º C isotherm was even more impressive, shifting from 238m to 88m and back down to 223m. Other species groups have also been relatively abundant. Our fishermen caught some fine mahi mahi, and the Red-footed Boobies that adopted our ship as their temporary home have been busy catching flying fish (see photos below). Seabirds continue to surpass expectations in terms of density and abundance, providing lots of excitement for the seabird team. In the strip transect we recorded 598 birds of 22 species with a daily average of 12 (range 10-14). Highlights include three Herald Petrels, single Cook's and Kermadec Petrels, and five Black-footed Albatrosses. Bonin Petrel (281) and Black-winged Petrel (97) were the most common birds recorded in the strip transect. Short-tailed Shearwaters appeared on the final day of the week, one day earlier than in 2002, and, for a brief time at least, will become the most abundant bird out here as they flood through this area on their way south from Alaska to breeding grounds in New Zealand and Australia.
Mahi mahi on line.
Red-footed Booby fishing.
|04 SEPTEMBER||Greetings from tomorrow! We are currently just across the dateline, and we’ve had a very good week. Things started out slow with the usual rough seas and no marine mammal sightings. But marine life picked up steadily as we moved west, and winds have gradually dropped to Beaufort 3-4. On Tuesday, we were treated to a once-in-a lifetime sighting – a very large, active group of over 70 Longman’s beaked whales, Indopacetus pacificus. In contrast to past sightings of this little-known species, the whales did not run away at high speed, but rather were only moderately evasive and allowed us to spend over an hour counting, observing, and photographing them as they rapidly surfaced all around us and occasionally breached (top photo below). The acoustics team successfully obtained what we believe are the first recordings ever made of this species in the absence of other cetacean species nearby. It was quite the amazing event! The excitement continued the following day, with a sighting of about 30 false killer whales, Pseudorca crassidens, the primary species of interest during this cruise. Weather was good, so we launched the small boat and obtained 4 biopsy samples and many photographs. Several of the animals had fresh wounds or healed scars, including one whale with a very ragged dorsal fin and many smaller wounds of unknown origin (bottom photo below). We also obtained some excellent recordings of the animals as they checked out our acoustic array. Other cetacean species seen this week include sperm whales, sei/Bryde’s whales, a Mesoplodon beaked whale, and striped dolphins. Our oceanographic team has documented that the increase in marine mammal sightings coincides with a marked shallowing of the mixed layer, from 60m earlier in the week to less than 15m during the last few days. Other marine life has also picked up, including squid (during the evening CTD station following our Indopacetus sighting), flying fish, and seabirds. Patterns of seabird density and diversity this week have been very consistent with what we found during HICEAS 2002. This week we recorded the highest densities for the cruise so far: 17 species on Wednesday and a daily average of 11 species. Bonin Petrel has been the most common species, on some days representing up to 61% of the birds recorded in the strip.|
Longman’s beaked whales, Indopacetus pacificus.
False killer whale with a very ragged dorsal fin.
|28 AUGUST||Leg 2 of the HICEAS cruise began on August 24, after three days in Honolulu. Chief Scientist Jay Barlow and scientists Abbie Sloan, Juan Carlos Salinas, Justin Garver, Yvonne Barkley, and Corey Sheredy departed at the end of leg 1, and five new team members joined the cruise: Candy Hall (Oceanographer), Chris Cutler and Rachel Struch (Mammal Observers), Eiren Jacobson (Acoustician), Cotton Rockwood (Visiting Scientist), and Karin Forney (Chief Scientist). During the next month, we hope to survey transect lines north of the Hawaiian Archipelago and westward to the far northwestern corner of our study area.|
Our first few days out have been typical of this region of low ocean productivity, with very few sightings and only a handful of acoustic detections. But at least we still have the wind. It’s been a steady 16-22 kts. Our only sightings have been distant unidentified dolphins and a sei whale today. The acoustics team has been battling equipment problems that have prevented us from obtaining bearings for detected animals, but our real-time acoustic identification system (ROCCA) successfully detected false killer whales on Wednesday. Unfortunately, the seas were too rough and the whales too elusive to find without our acoustic localization capabilities (although we did try!). Oceanographic operations are running smoothly, with interesting deep thermoclines. Candy reports that within one day, the mixed layer depth dropped from 48 m to 56 m. The 20º C isotherm is at 130 m and the 15ºC isotherm at 236 m – quite deep compared to our other study areas in the California Current and eastern tropical Pacific. Seabird diversity has been consistently high for the last 2 days (13 species per day), coinciding with a known hotspot north of the island of Kaua’i.
A sei whale (Balaenoptera borealis) encountered on August 27, 2010 at N24:47.01 W159:51.32.
Note the numerous round scars from cookie-cutter shark bites.
|21 AUGUST ||The first full report from the HICEAS survey has been posted on the web. Please visit the Reports from Sea link in the menu on the left to access the report. |
|14 AUGUST ||The HICEAS cruise reached the Hawaii EEZ study area today after a 10-day transit from San Diego. We transited along the edge of the North Pacific Gyre enroute to the study area. This area has notoriously low productivity, and we witnessed that first hand. We went for three consecutive days without a marine mammal sighting and with only a few acoustic detections. Even the bird densities were low with no birds "in the zone" on August 11. Marine life started to pick up yesterday, with a few more birds, including topic birds and frigate birds, and a couple of dolphin whistles. |
Today we had more dolphin whistles and a sperm whale acoustic detection that lead us to a nursery group of female sperm whales and their tiny calves. We saw what we thought was a large squid body floating at the surface, and as we went by, we could see it looked more like a placenta. We launched the small boat and recovered about 1kg of sperm whale placental tissue which we froze. The entire placenta was estimated to be 4-5 m long. We did our first CTD casts last night, and did a normal morning cast today. Spirits are high, especially now that we are seeing and hearing more things.The HICEAS cruise reached the Hawaii EEZ study area today after a 10-day transit from San Diego. We transited along the edge of the North Pacific Gyre enroute to the study area. This area has notoriously low productivity, and we witnessed that first hand. We went for three consecutive days without a marine mammal sighting and with only a few acoustic detections. Even the bird densities were low with no birds "in the zone" on August 11. Marine life started to pick up yesterday, with a few more birds, including tropicbirds and frigatebirds, and a couple of dolphin whistles.
Sperm Whale Cow/Calf Pair,
|07 AUGUST||Scientists from the Southwest Fisheries Science Center left San Diego, California, August 4 aboard NOAA Ship McArthur II on an expedition to survey marine mammals in the Hawaiian Islands Exclusive Economic Zone. The survey coordinator reports the ship's marine mammal and seabird sighting teams, oceanographers and acousticians are fully operational. Sightings on the first couple of days alternated between common dolphins and blue whales. In recent days, the dolphins are now striped and the whales have disappeared. The ship is headed into the great North Pacific desert, an area with few large fish or marine mammals, en route to Hawaii. The primary goal of this Hawaiian Islands Cetacean and Ecosystem Assessment Survey (HICEAS 2010) is to estimate the abundance and distribution of cetaceans within the Hawaiian EEZ using visual and acoustic methods. Concurrent with the abundance estimation, the expedition conducts an ecosystem assessment of the habitat in which the cetaceans are found. This year's survey is a collaborative cruise between the Southwest Fisheries Science Center and the Pacific Islands Fisheries Science Center. |
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