3/28/10

#46 Milk Does A Body Good

A few days ago while on survey we sighted one of the newer North Atlantic right whale mothers, #3360. (Click here to look up #3360 in the North Atlantic Right Whale Catalog.) Though her calf is already a good size, it still has a lot of growing to do by nursing on its mother's rich milk, and we were lucky enough to see some nursing behavior as we circled above the pair. We call the behavior "Probable Nursing" because we can't be sure that the calf is nursing without actually seeing the milk enter the calf's mouth. However the main cue that nursing is probably happening is a calf diving underneath its mother so that its head is just forward of the peduncle, where the body narrows out to the tail (see the accompanying photo). Usually the calf will surface for a breath on the opposite side of its mother from where it originally dove, and then repeat the process, surfacing next on the opposite side of the body again.

Photo Credit: New England Aquarium; Kelly Slivka.

As mammals, whales manage to nurse their young despite the difficulties of suckling underwater with a fixed jaw (allowing for no lip pursing/sucking). Calves need to pack on the pounds immediately after birth in order to build up their blubber layer and stay warm when they accompany their mothers to colder northern waters in spring, and some baleen whales have milk that is 40% fat in order to facilitate quick weight gain. For comparison, human milk is about 5% fat on average. Imagine gulping down milk that is the consistency of thick yogurt or cottage cheese, and you have a good idea of the diet of a right whale calf for about a year after birth!

-Kelly

3/25/10

#45 First Day of Spring...and Cownose Rays

The first day of spring brought us beautiful weather conditions and an array of interesting sightings. We spotted an unidentified shark (which we believe could have been a thresher shark based on its size and appearance), a leatherback sea turtle, and 3 right whale mom/calf pairs all within approximately 1 nautical mile of each other. We also observed 7 groups of cownose rays (Rhinoptera bonasus). While it is not atypical to see cownose rays this time of year in the Central EWS area, this was our first sighting of the season.

Since we broke track for one of these sightings, we were able to snap a few quick photos of the rays before returning to our survey, one of which you can see below. From a distance, these groups of rays, which varied from 50-150 individuals, look similar to water lilies floating on the surface of the water.




Cownose rays (aka: cowfish and skeete) get their name because of their squared, indented snout that resembles a cow’s nose. Their wingspan can reach up to 3 feet in length and they can weigh up to 50 pounds. Their distribution includes a large part of the western Atlantic (from New England to Florida), the Gulf of Mexico, and they can migrate as far south as Brazil. As migratory animals, it is believed that they move north in the spring and south in the fall in the Atlantic. So, perhaps the rays that we saw on the first day of spring were heading north. Based on the International Union for Conservation of Nature (IUCN) status, cownose rays are listed as "near-threatened". This means that although they do not qualify for "threatened" status, they could be considered threatened in the near future and the population should be re-evaluated regularly.

-Karen

Learn how divers care for the cownose rays in the Giant Ocean Tank at the Aquarium! And here is an interesting video of the Aquarium's cownose ray swimming in the GOT.

3/23/10

#44 March of the Mothers


As the right whale season draws to a close, things have quieted down a little bit in the waters off of Jacksonville where we fly our Central EWS surveys. It's regrettable to see the whales begin to leave, but it's the way it should be: we wouldn't want a lot of whales hanging around when there's no one here anymore to locate them for vessel traffic.

Interestingly, the sparse sightings we have been seeing over the past few days have been largely mother-calf pairs. In fact, for the past five days we have seen different mother-calf pairs each day! It's as if the mothers are marching through our survey area on their way back north-- like moms on parade. I think the whole team has enjoyed seeing all the mothers we've been watching throughout the season, as they're such a crucial indicator of the health of this population. We have been able to watch the calves grow from tiny gray squirts into strapping, strong youngsters who look plenty fit enough to survive the migration north and their first summer on the feeding grounds.


The calf of #2605 shows us its white belly.

However, we still don't have a final count on just how many new North Atlantic right whales have taken their place in the population this season. In the past couple days we have had two brand new mothers, bringing the current count up to 18. This great number gives good riddance to any worries about the productivity of the calving season we might have been harboring at the beginning of the year, when new moms appeared few and far between.














The calves of #2642 (left) and #3123 (right) have grown very large, and even have clear budding callosity patterns.


When I return north and visit the waters of Cape Cod Bay in two weeks, I'll be very excited to see if any new mothers show up that we didn't happen to see here on the calving grounds. But more thrilling will be to rendevous with the mothers and calves I saw in the southeastern U.S. once they reach the other end of their journey. I hope I find them healthy and thriving!

Photos credited to: New England Aquarium; Suzie Hanlan.

-Kelly

3/21/10

#43 It's A Boy!

Yesterday, Kelly and I spotted #1701 and her 2010 calf. (Click here to look up #1701 in the North Atlantic Right Whale Catalog.) While mom was taking relatively long dives (about 10 minutes or so), the calf remained at the surface displaying head lifting, rolling, and tail slashing behaviors. The rolling behavior in particular provided us with some important information — #1701’s calf is male! See the photo of the calf below.


Photo Credit: New England Aquarium; Karen Vale.

Many cetacean species are only slightly sexually dimorphic (oftentimes just a slight difference in size), so it’s nearly impossible to determine gender in the field. However, if you’re fortunate enough to see an animal roll over at the surface of the water, gender can be determined with the click of the camera. If an animal’s ventral side is exposed, the presence of genital slits can be determined. After reviewing the photos taken from the plane, we were able to determine that #1701’s calf is indeed male.

Gender of individuals in a population, especially one that is as critically endangered as the North Atlantic right whale population, is an extremely important demographic characteristic to monitor. A species needs an appropriate adult sex-ratio that fits their social system in order to ensure reproductive success. Reproductive success depends on many factors – sex-ratio being just one of these factors. Just by determining #1701’s 2010 calf’s gender, this will ultimately help with future conservation efforts for the entire population!

-Karen

3/19/10

#42 Safety First!

The New England Aquarium along with NOAA is committed to the safety of our aerial survey teams. So while talking about safety and safety equipment may be boring for some I find it exciting and fascinating. The technology that exists to the average consumer for safety equipment these days is affordable and easily accessible.

I thought I would take this opportunity to take you for a quick ride through the basics of our safety equipment. However, first, before you can come along with us you have to pass your aircraft ditching class. Each observer must be trained in aircraft ditching and water survival prior to the start of the survey season. Our training is conducted at Survival Systems USA in Groton, CT. To see what ditch training is like in the simulator check out this clip or this news report about the training.

Our aircraft is equipped with many of its own, FAA required safety features. However, we bring a lot of our own additional safety equipment aboard and most of it we are wearing! So first, lets get dressed for a survey flight. Keep in mind temperature and comfort when getting dressed in the morning and don't forget your hat and gloves for those cold days in January and February (remember we photograph from an open window at 1000 ft so it can be chilly).

Now that you have your thermal layer on its time to step into your full Nomex fight suit and your close-toed shoes. Nomex is a fire retardant material and relatively light weight so provides little thermal protection; however, it can feel extremely warm when surveying in the increasingly warm days of late March. OK, now over your flight suit goes your Switlik life vest. The life vest is constructed with dual inflation bladders. Only one bladder is needed to inflate for full flotation (in case the other gets punctured or does not inflate). Make sure you know where the inflation cord is and the manual inflation tube (in case the CO2 cartridges malfunction) and please don't forget to secure your leg straps. The leg straps keep the vest secure and tight around your chest; when inflated this allows for good positioning in the water. Without the legstraps and overall proper adjustment to the vest, inflation could pull the vest up around your neck and it could slip right over your head (depending on the size of your head). Proper life vest adjustment it very important so please make all the necessary adjustments before climbing in the plane.

Now lets dive inside the pockets of the life vest: in the left side pocket you will find your safety whistle, signaling mirror, blunt tip knife, safety streamer, thermal blanket and strobe/flashlight combo. The right side pocket holds your PLB (Personal Locating Beacon). The PLB is the latest generation of personal EPIRBs (Emergency Position Indicating Radiobeacon) that, once activated, sends a GPS location to rescue agencies via satellites. Everything in your vest is tethered securely so it won't fall out or float away if in water.


The safety briefing before your first flight will cover the location of all the safety equipment and the Egress Plan. The Egress Plan explains who is responsible for removing each piece of safety equipment from the aircraft and the order in which you will exit the aircraft in an emergency ditching situation. OK, time to hop in the plane. Once you get in and get comfortable you will need to fasten your seat belt, low and tight around your waist (just like they tell you on commercial flights). Now, acquaint yourself with your surroundings and the safety equipment located around you. Reach out and touch your removable EPIRB sitting in the seat pocket in front of you, the life raft to your side, the blunt tip knife (for cutting your seat belt off if needed) clipped in place in front of you, the submersible hand-held VHF radio, the handle to the door and the lever to jettison the side window. Lastly, check around your feet, most of our cords are secured under the carpet or along the walls of the fuselage but its always good to double check. (See all the equipment that we cram into a little airplane on this previous post - from cameras to laptops to satellite phones and GPS devices.) Next, headset on and have a good flight.

Meet the folks who fly us safely over the calving grounds here and here. This post is about our new ride! Finally, read about Aquarium researcher Amy Knowlton's real life aircraft ditching experience in 1987.



Photos credited to Kelly Slivka.