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Discovery - Virtual tours of the underwater world
Various members of the NORFANZ team kept a diary of their experiences over the four-week voyage. You can read about their experiences below.
08.00hrs: 6 n. mls SW of Mt Egmont
22.00hrs 76 n. mls off Kaipara Harbour ; heading NW at 12 knots.
Weather: wind WNW 23 knots; sea slight NW swell 0.5m.
We left Wellington Harbour last night on schedule at 20.00hrs (8pm). It was a special moment for all on board who had worked very hard over the last 2-3 years to make this voyage happen. After a hectic day ensuring that 1001 items of equipment were safely packed away, we said our goodbyes and finally we were off!
Once outside Wellington Harbour we experienced that familiar roll of a vessel at sea. The weather was very good, but nevertheless it takes a day or two to adjust to the constant motion. To begin with the body resists the movement and gets tired. But eventually the senses relax and the muscles and balance start to work with the movement, not against it.
This morning I was not feeling very good, having a tummy ache and feeling too hot. I felt best sitting down, which was okay because most of the day was taken up with meetings of the Science Committee. We fine-tuned our samplings plans and arranged our scientists into two shifts dividing the 24-hour day in half -- 03.00 to 15.00hrs and 1500 to 03.00 hrs. Not easy hours to work, but as with the vessel movement one adapts and gets used to getting up and going to bed at unusual times.
Today the scientists and our crew were busy rigging the sampling gear and making our work areas operational in preparation for our first sample stations tomorrow afternoon.
Let’s hope this good weather holds and my sea sickness goes away. Despite feeling uncomfortable early on, it is great being at sea again. I wonder what tomorrow will bring?
17.00hrs: Trawling at 3 knots.
Wind NW 13 knots; sea slight, SW swell 1m. Air temp 18.5 C, sea surface temp 18.9 C.
The weather today has been beautiful and sunny with a gentle swell, ideal for developing our “sea legs” and sorting out our work areas. We arrived at our first sample station around mid-day. After exploring the area with echo sounders a suitable area of seabed around 350-500m deep was selected for a trawl shot. The trawl was an orange roughy bottom trawl modified with two cone nets in the wings to catch small specimens. Later we shall be sampling between 550-1000m and 1050-1500m depth with this gear.
It was a very good feeling seeing the trawl disappear down the stern ramp and into the clear depths – our first station and at last we shall be collecting some fishes and invertebrates. After a standard tow of 1.5 kms the trawl was brought up.
Once safely secured, all the scientists rushed onto the deck to search the cod end, cone nets and net meshes in a flurry of excitement. As it happened the net was nearly empty with just a few specimens of rubyfish, orange perch, and sea perch, to keep the fish scientists happy, and one arrow squid, and a handful of small prawns for our invertebrate specialists.
Although the catch was small it was ideal for testing our processes and procedures. Fishes were taken below to be identified, weighed, photographed, documented and preserved. Invertebrates were processed on deck and in the adjacent plankton lab.
As expected there were a number of “log jams” of specimens when delays caused a build up.
Forgotten items of equipment and systems not working as well as they should contributed to the problem. However these difficulties will be ironed out over the next few stations as we get more efficient at handling the specimens and collecting a substantial amount of data.
We are now working in our shifts. Mine is 03.00-15.00hrs, which means I am over time already. However because we have a lot still to do and there are two more trawls planned tonight before changing gear, I intend to keep working. We shall be steaming for about 20 hours tomorrow to the next site, so time to catch up on some sleep then.
Our trawl gear is working well and the seabed is not too rough, so we shall attach the benthos headline camera to the next trawl shot. This is a valuable piece of equipment that we cannot risk loosing on rough ground. The camera and lights photograph the bottom in front of the trawl to provide a picture of the seabed and the changes in habitat. In addition to some interesting photos, this habitat information can be plotted and compared with the samples caught, and so help us understand where deep sea species live.
It is going to be a busy night – more tomorrow.
14.00hrs: Steaming at 14 knots.
Wind SW 5 knots; sea slight, SW swell 1m. Air temp 19.7 C, sea surface temp 20.0 C.
Last night we worked on fishes and invertebrates taken by the orange roughy trawl. Although catches were relatively small, we collected some valuable specimens, including at least two fish species new to New Zealand. The invertebrates are more difficult to identify on board, but our specialists tell me that we have collected a number of species new to New Zealand and to science.
After midnight we changed gear to the heavily armoured, epi-benthic sledge nicknamed “ Sherman ”. This is a rectangular metal box about 1 x 2m in size, built like a tank to sample very rough bottoms. This sledge is designed to sample invertebrates, sediment and rocks, which are collected in a net protected by a wire bag.
Sherman was operated down the slope in three tows similar to the path taken earlier by the trawl. A number of sponges, molluscs, echinoderms and prawns were collected.
The sledge also captured some small rattail fishes and a rare slickhead.
After completing three Sherman tows we said goodbye to the New Zealand slope and headed northwest towards the remote Norfolk Ridge. It will take over 20 hours steaming to reach our first seamount station. On the way we shall shoot the mid-water trawl down to about 1200m depth in order to sample the deep pelagic fauna – that weird and rarely seen group of fishes, prawns and squids. These are usually black or red in colour, some with bizarre shapes and often with rows of flashing blue, red or green lights on the body.
Upon reaching the seamount we shall shoot the mid-water trawl again to compare this fauna with that of the open ocean. The differences will help us assess the effects of the adjacent seamount on the pelagic life.
Meantime we have a long steam in front of us, which will allow both watches to catch up on some sleep, to consolidate our records, and prepare for tomorrow’s operations.
11.00hrs: Wind SE 20 knots; sea moderate, SW swell 1-2m. Air temp 19.8 C, sea surface temp 21.0 C.
We are presently steaming slowly northwards mapping the seabed in order to locate the top of a seamount that we plan to sample today. Published charts of the area are unreliable due to the small amount of survey work carried out here. Therefore we are building up our own accurate bottom charts using a system called swath mapping that uses a special type of echo sounder.
Once the area has been mapped we can assess the safest track along which to shoot the sampling gear. Also we can see how hard and rough the seabed is and so select an appropriate trawl or sledge to work on that type of bottom. If the gear works as planned we shall have a very busy next 24 hours, sorting and identifying the samples.
Last night we carried out a mid-water trawl down to 1295m depth over a bottom depth of 3600m. The net was towed for 1.5 hrs at a speed of 2.5 knots. This is much slower than usual for this type of net, but was necessary because the cod-end has a special fine liner inside that would blow out at a faster speed. The liner is needed to retain the numerous small fishes, squids and prawns that inhabit these depths.
This was our first shot with this net and liner and we were not sure how well it would work at a slow towing speed because there is a risk of crossing the trawl doors and tangling the net. However, as it happened it worked very well and captured some scientifically valuable specimens as described below.
It is 03.15hrs and we have just finished an extremely busy five hours identifying, photographing and recorded the last catch which consisted of shrimps, squids, octopods and fishes. At this station we used a 5-mesh mid-water trawl designed to sample creatures that live in open water. These animals spend their whole lives without seeing either the surface 100’s of meters above or the sea floor 100’s of meters below. They are truly swimming in “inner space”.
Because the creatures we are after are so fragile and delicate, it took over an hour to haul the net back up to the surface – haul too fast and the water pressure would damage them. When the trawl was finally emptied, the catch would have filled a shopping bag. This gives some idea of the low density of life at these mid-water depths. However what a great mix of weird and wonderful animals we collected.
It has taken a team of five fish experts over five hours to sort and identify the 35 fish species sampled. Some have exotic names such as viperfish, snipe eel and hammerjaw. Others are very are and have no name; two species are new records for the region.
Our photographic team has been busy photographing the fresh specimens and capturing the fresh colours, some for the first time for the species.
The accompanying photo shows Dr John Paxton, from the Australian Museum Sydney, holding a slender angler fish named after him – an appropriate end to an exciting shift.
11.00hrs: Wind SE 28 knots; sea moderate, SW swell 2-3m. Air temp 20.1 C, sea surface temp 21.2 C.
We had a rough night - the sea was rough and the seabed was rough. Together these caused problems that were in turn rough on the ship’s officers who were trying to locate suitable tracks to tow, and to the crew who staunchly mended the broken gear. The scientists also had a rough night, all passionately hoping for some good samples to work on but instead becoming seasick, and our watch leaders who had to continually modify sampling plans to suit the tough conditions.
The first part of the night was spent trying to locate a seamount that was mapped but was not in fact present. Later we found some pinnacles that were not mapped but were unfortunately too small to sample. When we did find an area that appeared to be okay on the echo sounder – not being too rough or sloping – during the first shot our dredge became stuck fast, then during the second shot Sherman our heavy-duty dredge was badly damaged.
In this area the bottom is very hard and deceptively flat but fractured with fissures and valleys that are nearly impossible to tow our bottom gear over. This uncharted area is a real challenge, so we have moved closer to Norfolk Island to operate on some softer seabed that hopefully will not destroy our sampling gear.
Yes, we did find better ground to work. However we continued to hang up the gear on the bottom. The orange roughy trawl became fast but broke free when we reversed over the top of it, then we used the beam trawl for the first time but the beam broke in half (which it is designed to do). Due to these hang-ups neither set of gear worked well so catches were small.
Nevertheless, we still managed to sample 3-4 boxes of fishes, including two species new to science. One is a distinctive grenadier or whiptail about 80cm long caught at about 650m depth that our specialists reckon is closely related to one off Japan and to another off New Zealand. This attractive fish has distinctive saddles across the body, a brown back and blue-green sides, and a striped anal fin.
The other new species is a pelagic fish that was picked up as the net was being hauled. This small dragonfish is less than 7 cm long, has a chin barbel with a light organ at the tip, but also has a light organ with filaments at the tip of the enlarged first ray of the pectoral fin.
Hopefully more specimens of the colourful grenadier and the unusual dragonfish will be taken in the next hauls.
06.00hrs: Wind SE 21 knots; sea moderate, SW swell 2-3m. Air temp 20.5 C, sea surface temp 22.0 C.
As I write this I can see Norfolk Island through my porthole. The wind is blowing strongly, whipping the tops off the waves, the sky is overcast, and although it is not cold, the area does not have the feel of a tropical paradise. It is almost bleak and certainly very isolated.
Overnight we had success with the beam trawl which came up from 350m with some good samples of both invertebrates and fishes. The last night station shot was with the mid-water trawl targeting the deep pelagic fishes that rise up in the water column during the hours of darkness. On the first attempt the net became tangled due to several broken floats getting caught in the meshes. So it was hauled, untangled and repaired quick time, in order to be re-shot just on our watch change over at 03.00hrs.
The net is just about up, having run at 1200m depth for 2 hours, and taken another 30 minutes to shoot and haul. The mid-water trawl sampled a variety of fishes, prawns, and squids, with even a few jellyfish remaining intact. Judging from the 5kg of lanternfishes, dragonfishes, anglerfishes, loosejaws, lighthousefishes, hatchetfishes, and others we shall be busy sorting and identifying right through to the next site.
I have just finished a 12-hour watch, working on two sample stations for 10-hours. I am exhausted, but thrilled that our gear has worked so well. The mid-water trawl contained over 00 fish species, several of which are not identifiable and are probably new.
The beam trawl contained mostly invertebrates, but the 10 fish species it caught were spectacular, being multi-coloured and in very good condition. The fish sample included two new species, some rare ones, and a few that represent range extensions.
Currently we are swath mapping this area to locate a safe route for the trawls and dredges over the coming night and next day Having learned the hard way about the dangerous nature of the seabed from the last site, we are being very cautious about where we shoot the bottom sampling gear. We need to get it back intact and complete with its sample of scientifically valuable the marine life.
The photo shows Scientists on RV Tangaroa sorting hundreds of pelagic fishes taken at 1200m depth near a seamount.
More tomorrow.
16.00hrs:
Wind S 33 knots; sea rough, S swell 2-3m. Air temp 21.1 C, sea surface temp 22.0 C.
For the last day and half now, the invertebrate specialists on board RV Tangaroa have been busy sorting and trying to identify a major sample of animals that live on the sea floor. Since invertebrates are the most abundant kinds of marine life, they are very important in a biodiversity survey such as the NORFANZ voyage.
If we were able to collect and identify every animal inhabiting even a small section of the sea floor (say the size of a coffee table), we would find several hundred species of invertebrates. But it would take several specialists many months with a microscope to study and identify most of them.
Studies of seamounts elsewhere in the world suggest that the sea floor where we are working harbour a good variety of corals, crabs, sea stars and a myriad of smaller invertebrate animals. But we are finding that the seamounts of the Tasman Sea are so rocky and steep that it is difficult to get the battered sledge and trawls back on board with the samples intact.
At last, however, our persistence is paying off. We have found some areas flat enough to use the fine-meshed beam trawl and with this have been able to sample a great diversity of corals, gorgonians, and sponges. Also sampled are many shrimps, crabs, shells, worms and other creatures that live among this marine forest. Many will be new to science.
One of the major goals of this research voyage is to investigate whether or not each seamount has its own unique fauna of marine life. Seamounts are isolated rocky peaks, truly islands in the deep sea, because many creatures that live on them cannot survive in the deep muddy sea floor in between.
Some invertebrates like crabs, shrimps, sea stars, sea urchins and some corals have planktonic larvae that can be carried great distances by the ocean currents. As a consequence these are often widely distributed. Other kinds of invertebrates, such as smaller crustaceans and some kinds of worms, cannot disperse so far, even as larvae. It is study of these later groups of invertebrates that, through investigation of their diversity and evolutionary relationships, may ultimately tell us most about the seamounts that they live on.
