Joe Roman, Dave Johnston, Meagan Dunphy-Daly and Andy recently published a paper in Trends in Ecology and Evolution on the recovery of some populations of marine mammals. Using elephant seals, gray seals and humpback whales as examples, we discuss the challenges facing managers when populations of these marine predators recover and recolonize their former ranges. In the paper we argue that we should celebrate these conservation success stories and plan for more in the future. We emphasize that this does not diminish the urgency with which we need to deal with critically endangered, small and declining populations, such as the vaquita. You can access the article here.
We’re now almost half-way through our spring field season – we’ve been busy working off Cape Hatteras for the past two weeks. We have deployed six satellite-linked transmitters on pilot whales and one more on a pelagic bottlenose dolphin. Two of the tags we have deployed on pilot whales also transmit data on dive duration and depth.
On Monday we also deployed our first Digital Acoustic Tag of the field season on a pilot whale. These tags record depth, orientation and acceleration using a suite of sensors as well as a record of the acoustic environment of the tagged whale. The tags sample the orientation of the animal in three dimensions with sufficient resolution to capture individual fluke strokes. We program the tags to release from the animal at a pre-determined time by venting the suction cups (this works most of the time). A VHF transmitter embedded in the tag helps us to track the whale and to recover the device. Once the tag is jettisoned from the whale and recovered, we download data from the tag to a computer.
We attached the tag to a whale that we found in a large aggregation that contained several of our satellite-tagged animals. We followed it for six hours from our small Rigid-Hulled Inflatable Boat, the Exocetus. We kept track of the composition of the group of the tagged whale – it was initially in a pretty tight group of 17, but peeled off from this group with four other whales for a couple of hours before rejoining the original group in another large feeding aggregation. It’s always interesting to peer into the lives of these animals for a few hours. We successfully recovered the tag at about 5:30 and were back on shore by 8:00 PM.
As always, it’s been a bit of a struggle to deal with the weather 40 miles from shore – we’ve turned around twice this week when sea conditions turned out to be worse than forecast. But it’s always worth it when we manage to get offshore – on Monday we were also treated to sightings of two Great Skuas (which breed in Iceland), a flock of phalaropes and a ton of scalloped hammerheads in and amongst the pilot whales.
This spring we are once again deploying satellite tags on whales and dolphins off Cape Hatteras with Daniel Webster from the Cascadia Research Collective. Yesterday (May 16th) was our first day of real work and we managed to deploy three satellite tags on short-finned pilot whales. Two of the tags will transmit locations only and the third tag will also send information about the whale’s diving behavior. We were able to obtain small biopsies of skin and superficial blubber that will allow us to determine the sex and reproductive status of the tagged whales.
In addition to the pilot whales, which were numerous offshore yesterday, we encountered bottlenose dolphins and a solitary Risso’s dolphin. Scalloped hammerhead sharks were common amongst the pilot whales, as they usually are, and we also saw a couple of large manta rays. And, finally, we also sighted small numbers of sooty and greater shearwaters and Wilson’s storm petrels.
This work involves very early mornings, and a long transit to and from Oregon Inlet to our study site 35 nautical miles from shore. We usually leave the dock at 6:00 AM and are at the shelf break by 8:30 or so, returning home before 6:00 PM, so that we can fuel up the R/V Richard T. Barber for the next day. So, very long days, but it is worth it for the amazing experience to be surrounded by pilot whales offshore.
Thanks to support from the U.S. Naval Facilities Engineering Command Atlantic for making this work happen.
We are proud to have joined the Palmer Long Term Ecological Research (LTER) team, studying the the ecology of the Antarctic Peninsula, supported by the National Science Foundation. This is a six-year project and our component is led by Read Lab alum Ari Friedlaender, now a faculty member at Oregon State University, together with Dave Johnston, Doug Nowacek and Andy as co-PIs. This January, Andy and Zach are sampling humpback whales from Palmer Station while Dave and Ari are sampling and deploying satellite-linked tags on humpbacks over a broader area of the Antarctic Peninsula on the Antarctic Research Vessel Laurence M. Gould. You can follow our adventures here and here. And check out the Palmer Station webcam here.
We wrapped up this season’s satellite tagging project with Daniel Webster and Cascadia Research Collective with an incredibly successful day on the water last Tuesday. Our project is focused on the behavior of several deep-diving odontocete species off Cape Hatteras, including short-finned pilot whales, Risso’s dolphins and bottlenose dolphins.
But there is one creature off the coast of North Carolina that we know very little about and has proved to be very challenging to work with. Most days we head offshore, we are hoping to work with Cuvier’s beaked whale (Ziphius cavirostris). This is a deep-diving odontocete that can spend well over an hour below the surface searching for and foraging on squid at depths exceeding 2,000 m (yes, that’s holding your breath while diving for 2 kilometers and then returning another 2 km to surface for the runners among you). They surface only occasionally and for no more than for a few minutes at a time. This unique dive behavior makes it very difficult for us to approach the animals to deploy tags, and is one reason why scientists know very little about this species.
There is some predictability to their dive patterns, however, that allows us to anticipate when and where they are going to surface. Our efforts paid off last week after an entire summer searching for beaked whales and learning their behaviors off Cape Hatteras. On our last day of the satellite tagging project, 16 September, we located and tracked a group of 5-6 Cuvier’s beaked whales long enough to deploy our last two satellite tags, one location and depth-transmitting tag (Mk-10) and one location-only tag (SPOT). We anticipate that the tags will track the movements and dive patterns of these two individuals for 30-45 days. You can track the animals on https://www.movebank.org.
We’ll be headed back out off Cape Hatteras in a couple of weeks with Ph.D. student Joy Stanistreet to deploy five Marine Acoustic Recording Units (MARUs or pop-up buoys) to record North Atlantic right whale (Eubaleana glacialis) migratory movements. We also hope to deploy more DTags on short-finned pilot whales to coincide with seismic surveys being conducted in the area, so check back …
On Thursday we headed out on the R/V Barber with the intention of deploying satellite tags on beaked and pilot whales. This is a continuation of the satellite tagging effort we conducted earlier in the summer with Daniel Webster and Robin Baird from the Cascadia Research Collective. We headed offshore approximately 40nm east of Cape Hatteras, NC to the ziphiid ‘hot spot’ and immediately saw a beaked whale. It surfaced several times then dove but, despite staying in the area for 30 minutes and scanning in all directions, we did not resight it.
We decided to look for other animals and quickly came across a group of 15 pilot whales. We tagged one of the pilot whales with a Spot satellite tag that will provide data on the whale’s location over the next couple of months and continued surveying offshore, in hopes of running across beaked whales in the deeper waters. We didn’t find any more beaked whales, so we decided to head back inshore and look for pilot whales and soon found another group of about 30 animals. They were scattered in small subgroups and we worked our way from one group to the next, successfully deploying two more Spot satellite tags and two Mark-10 tags that will record information on dive depth as well as location. We focused on pilot whales with distinctive dorsal fins, which will allow us to identify the animals even after the satellite tags have been shed. The wind picked up in the afternoon and continued to blow throughout the evening and into Saturday.
On Sunday we had another productive day satellite tagging despite poor tagging conditions in the morning. The seas flattened out by mid-morning and we managed to locate several scattered groups of pilot whales as we worked our way north along the shelf break. We deployed three more Spot satellite tags on pilot whales and then decided to head farther offshore to look for beaked whales. We soon came across a small group of about 20 offshore bottlenose dolphins that came to check out the boat and bow ride for a few minutes. The group was fairly cooperative so we deployed a Spot satellite tag on one of the animals.
As we were tracking the tagged individual to take photos of the tag placement, we saw a large animal breeching in the distance. We immediately switched into tagging mode and made a run for the breaching animal in the hoped that it was a beaked whale. As we closed on the animal we realized it was not a beaked whale but a sperm whale! We are not permitted to tag sperm whales this year, but we hoped to get close enough to collect a biopsy sample for genetic analysis. The whale remained subsurface and just out of reach, so we decided to abort the sample collection. But as often happens, one sighting will lead us to another interesting sighting, a beaked whale no more than 500m from us! We ended up sighting 5-6 Cuvier’s beaked whales before we had to head in due to fading daylight. We weren’t able to deploy a tag but were encouraged that we were able to track the animals for over two hours and make several very close approaches. We have two more days of field work before we wrap up satellite tagging efforts for the season. Check back with us again soon to see where some of the tagged pilot whales and bottlenose dolphins move over the next few months.
Last month Andy attended the fifth meeting of the International Recovery Team for the Vaquita, known as CIRVA. The full report of the meeting is available here on the web site of IUCN Cetacean Specialist Group, but here is a brief summary of the dire state of the species.
The vaquita, a small porpoise found only in the upper Gulf of California in Mexico, is one of the world’s most endangered mammals. In the past three years, half of the vaquita population has been killed in fishing nets, many of them set illegally to capture an endangered fish. Fewer than 100 vaquitas remain and the species will soon be extinct unless drastic steps are taken immediately.
The species was described in 1958 and has the smallest range of any whale, dolphin or porpoise. Vaquitas live in an area used intensively by fishermen from three small towns along the shores of the northern Gulf of California.
Vaquitas die after becoming entangled in gillnets. Gillnets are designed to entangle fish and shrimps but also capture other animals, including porpoises, dolphins and turtles. The Government of Mexico has been pursuing a conservation plan for the species that includes a refuge, where all commercial fishing (including with gillnets) is banned, and a program to encourage fishermen to switch to fishing gear that does not threaten vaquitas. Over the past five years, the Government invested more than $30 million (U.S.) in these efforts that slowed, but did not stop, the decline of the species. Scientists have warned for almost twenty years that anything short of eliminating gillnets would be insufficient to prevent the extinction of the vaquita.
A new, illegal fishery has emerged in the past few years that is an even greater menace to the vaquita. Many vaquitas have died in nets set for totoaba, a giant fish that can reach 2 m in length and 100 kg in weight. This endangered fish is prized for its swim bladder, which is exported to China where it is used as an ingredient in soup and believed to have medicinal value. Thousands of swim bladders are dried and smuggled out of Mexico, often through the United States. The remainder of the fish is left to rot on the beach. Fishermen receive up to $8,500 for each kilogram of totoaba swim bladder, equivalent to half a year’s income from legal fishing activities.
At a meeting in July 2014, an international recovery team advising the Government of Mexico warned that time is rapidly running out. Unless drastic action is taken immediately, the vaquita will be lost. Mexican authorities must eliminate the gillnet fisheries that threaten the vaquita throughout the entire range of the species and enforce this gillnet ban. The Government must also stop illegal fishing for totoaba. The Governments of the United States and China must help Mexico eliminate the illegal trade in totoaba products. Unless these steps are taken immediately, the vaquita will follow the Yangtze River dolphin into oblivion and become the second species of whale, dolphin or porpoise driven to extinction in human history.
June 27th marked the end of a very successful summer field season. After waiting for workable weather for almost a week, the wind finally died down on Friday, only to be replaced by rain and thunderstorms. We waited out the lightning and the rain at the Oregon Inlet Fishing Center and got a late start, but it was worth it as we ran into pilot whales as soon as we arrived at the shelf break just after noon.
The whales were moving steadily south along the break and we quickly had a DTag on a large male. Conditions were good and the group was co-operative, so we decided to deploy a second tag in the same group – the elusive ‘Double Tap’ of whale tagging. (Who doesn’t love a zombie comedy with Bill Murray in it?)… Soon, we had two whales tagged and things were going swimmingly.
That is, of course, until our group decided to join another couple of hundred pilot whales in a feeding aggregation that also included about 15 charter boats, commercial troll boats and recreational vessels. Fishermen often target groups off pilot whales, believing that they ‘carry’ tuna underneath them. It is likely that the pilot whales and tuna are both attracted to the same prey (squid), so the strategy is a good one – we saw several boats hooking up with fish while we were dodging and weaving trying to stay out of the way. It was difficult to keep track of our two tagged whales in all the action, but we persevered.
Matt’s initial look at the dive data from the two tagged whales shows that they were quite synchronous throughout the afternoon. An early foraging dive was followed by steady travel to the big aggregation, followed by long dives of 10-15 minutes in duration and to 400 m in depth, interspersed with resting periods at the surface. This is typical pilot whale foraging behavior, but it’s cool to be able to document simultaneous behavior of the two animals.
We managed to complete a full playback sequence with the two whales and both tags came off exactly as planned, at the end of their planned deployment periods. We had both tags back in the boat and were on our way home by 5:00 PM. A great end to what has been a really productive field season.
We wrapped up our spring satellite tagging project with Daniel Webster of Cascadia on June 11 and 12. On the first day we had Joel Bell from the Navy along with us and he turned out to be very good luck and an excellent videographer. We had great conditions and managed to deploy six satellite-linked tags: four on pilot whales (including a MK-10 dive recorder) and two on pelagic bottlenose dolphins (one of which was a dive recorder). We also obtained a biopsy sample from one of the pelagic, small-bodied spotted dolphins (Stenella frontalis).
The weather did not co-operate with us so much on our second day – with intermittent rain and poor visibility. We tried to dodge the rain for much of the morning without success and as we headed in after deciding to call it a day, Heather spotted a mixed group of common and spotted dolphins and we were able to deploy a satellite tag on one of the common dolphins.
To date this year we have deployed 17 satellite tags on odontocetes off Cape Hatteras – one Cuvier’s beaked whale, 12 short-finned pilot whales, three pelagic bottlenose dolphins and the one common dolphin. We are still getting great data from almost all of the animals, most of which have remained in the vicinity of the shelf break off Cape Hatteras.
After a short break for windy conditions, we were back on the water on June 16 to continue our playback experiments with short-finned pilot whales off Cape Hatteras. In this project, funded by SERDP, we are examining the response of odontocetes with different patterns of social organization to the sounds of predators (mammal-eating killer whales). We tagged a large male pilot whale with a Digital Acoustic Tag on June 16 and conducted a full four-hour playback suite with this animal before obtaining a biopsy and retrieving the tag. We also collected a biopsy from a sperm whale that wandered by and photos of two of our satellite tagged animals. Another great day on the water off Cape Hatteras.
Daniel Webster from Cascadia flew back from Montana this week to work with us deploying more satellite tags on large odontocetes off Cape Hatteras. We were also fortunate to have Dr. Emer Rogan, from University College Cork in Ireland, working with us for two days as part of her sabbatical visit.
We’ve been enjoying a few days of early summer weather with workable conditions at our field site, which is about 40 nautical miles from shore. It’s a long two-hour commute to and from the shelf break, but the diversity and density of cetaceans out there make the trip worthwhile.
On Saturday we were able to deploy a location-only satellite tag on a large male pilot whale and obtain a biopsy sample (from the other side of the fin) to confirm the sex of the animal. We also had a great encounter with a group of unusually friendly Risso’s dolphins, with two animals repeatedly approaching the bow of the R/V Barber. We were hoping to deploy a tag on one of these animals, but they were too quick and we were working in a pretty good chop.
We had spectacular weather conditions on Sunday – glassy calm for much of the day – a perfect day to search for beaked whales. We found three groups of Cuvier’s beaked whales, but were unable to relocate any of them after they dove. Trying to tag beaked whales involves a lot of time waiting for them at the surface as they can dive for 75 minutes or more.
We did manage to deploy three more tags on pilot whales on Sunday – two dive recorders and one location-only tag. Unfortunately one dive recorder was shed immediately but we have high hopes for the other two tags and we are still receiving great data from the three whales we tagged in May.