genetic analysis – NOAA Teacher at Sea Blog

August 4, 2007April 1, 2021

Methea Sapp-Cassanego, August 4, 2007

NOAA Teacher at Sea
Methea Sapp-Cassanego
Onboard NOAA Ship Delaware II
July 19 – August 8, 2007

Mission: Marine Mammal Survey
Geographical Area: New England
Date: August 4, 2007

Weather Data from Bridge
Visibility: 5 in haze lowering 3 to 5 in showers
Wind Direction: Southwest
Wind Speed: 10-15 knt increasing to 20 knt.
Swell height: 3-5 feet building 4-6 feet

A solitary ocean sunfish basks in the sun while a shearwater skims by.

Science and Technology Log

Rotations have been going like clock-work, although today’s sightings have again been numerous we still have not found any more right whales. Again I’ll fill today’s blog with some species profiles of animals we’ve seen today. By the way, the sightings list for today includes, pilot whales, minke whales, offshore bottlenose dolphins, common dolphins, white-sided dolphins, beaked dolphins and harbor porpoise. We’ve also seen a few Mola mola which are not tallied since they are not marine mammals.

Atlantic White-sided Dolphin (Lagenorhynchus acutus) Researchers and scientists also refer to this animal as a “Lag.” Identification: At first glance the Atlantic white-sided dolphin looks very much like the common Atlantic dolphin. Its body is slightly more robust then that of the common Atlantic dolphin; its tail stock is also thicker. The upper portions of the body are black while the lower belly and chin are white; a long horizontal grey strip bisects the upper and lower body portions. The flippers are also grey. Max length and weight: 510 pounds and 9 feet. Diet and Feeding: Fish and squid Migration: No organized or seasonal migration Distribution: Found in cold waters of the northern North Atlantic from the Northeast United States to Northern Europe and Southern Greenland. Special Note: Atlantic White-sided Dolphins are especially gregarious and are often seen swimming along the side of boats and bow riding. They will also mingle and feed with fin and humpback whales. Several hundred are caught and killed each year as a source of food by the Faroese Island people.

References

Collins Wild Guide: Whales and Dolphins. HarperCollins Publishers, New York, New York. 2006.

Ocean Sunfish (Mola mola)

Identification: This oddly shaped fish is most easily identified when it is basking at the surface. Its large disk-like body is pale grey to white in color; lacks a true tail; both the dorsal fin and anal fin are extremely elongated so that the fish is as tall as it is long. Sunfish are solitary but may occasionally be found in pairs.

Max length and weight: Averages 5 feet 9 inches in length and 2,200 pounds. Records exist of sunfish spanning 10.8 feet in length and weighting just over 5,000 pounds.

Diet and Feeding: Primarily seajellys but also feeds on salps, squid, crustaceans, comb jellies and zooplankton. Sunfish are pelagic and may feed at depths just shy of 2,000 feet.

Migration: No organized or seasonal migration

Distribution: Ocean sunfish are found globally in both temperate and tropical waters. Research suggests that populations of sunfish inhabiting the Atlantic and Pacific have greater genetic differences than populations in the Northern and Southern Hemispheres.

Special Note: The ocean sunfish poses no threat to humans and is commonly approached by divers. Its meat is of minimal economic importance although there seems to be an increasing popularity in sunfish cuisine and it is considered a delicacy in some parts of the world. The sunfish has few natural predators due to the thickness of its skin which can measure up to 3 inches in some places. More often than not the sunfish encounters its greatest threat when caught in fishing gear. Sunfish by-catch totals ~30% of the total swordfish catch off the coast of California and ~90% of the total swordfish catch in the Mediterranean.

Impressive size and startling appearance make the ocean sunfish a favorite attraction at the Monterey Bay Aquarium. This photo is freely licensed via Wikimedia Commons and is courtesy of Fred Hsu.

August 3, 2007April 1, 2021

Methea Sapp-Cassanego, August 3, 2007

NOAA Teacher at Sea
Methea Sapp-Cassanego
Onboard NOAA Ship Delaware II
July 19 – August 8, 2007

Mission: Marine Mammal Survey
Geographical Area: New England
Date: August 3, 2007

Weather Data from Bridge
Visibility: 5 in haze lowering 3 to 5 in showers
Wind Direction: Southwest
Wind Speed: 10-15 knt increasing to 20 knt.
Swell height: 3-5 feet building 4-6 feet

Pilot whales as seen from the zodiac—note the calf in the foreground. Photo courtesy of Brenda Rone. — Pilot whales as seen from the zodiac—note the calf in the foreground.

Science and Technology Log

Today was another great day for sightings. Critter counts include sperm whales, white sided dolphins, a whopping 17 minke whales, a Sei whale, offshore bottle nose dolphins, a finback whale, another pod of pilot whales and 100’s of common dolphins. At one point during my starboard observation shift, both I and my portside counterpart were calling off sightings so rapidly that the recorder was having problems keeping up with us. We both paused for a moment and pulled away from the big eyes to look around and discover that we were surrounded by literally 100’s upon 100’s of common dolphins. The sea was frothing with their activities; some doing aerobatics, others charging, some came to bow-ride of the ship, while other could be seen chasing large fish which were identified as yellow-fin tuna.

Researchers position themselves to rejoin the main ship. — Researchers position themselves to rejoin the ship.

In a repeat from several days ago the pilot whale sighting prompted another launch of the zodiac…only this time I got to climb down the Jacob’s ladder and go for a zodiac ride which brought me as close to pilot whale as I could ever hope to be. We were able to procure 5 tissue samples for further genetic study along with an untold number of dorsal fin photographs. (Please see log from August 1^st for further explanation of these genetic studies and photos.) My job on the zodiac was to fill out the photography data sheets which record the GPS headings, frame numbers, animal position within pod, approximate size of animal, special markings on the animal, if an attempt to biopsy the whale was made, if the shot resulted in a hit or miss….etc. I was madly recording all this information as cameras were shooting and crossbows were firing and the whole experience whizzed past me. I hope I didn’t forget to record anything!

An ill-fated Northern yellow warbler rests on the deck of the DELAWARE II — An ill-fated Northern yellow warbler rests on the deck of thevDELAWARE II

Aside from all the sightings (some of which have become rather common place), and my zodiac ride I really have nothing left to report for the day….except of course that the day flew by. In fact every day passes in a blink…even the foggy ones. I suppose that’s what happens when each day is filled with something new to see and do. Before I sign off for the day I’ll leave you with two more species profiles. One of which may surprise you!

Yellow warbler (Dendroica petechia)

There are approximately 40 subspecies of this widely distributed little bird. This bird, in particular, was most likely from the subspecies aestiva thus making it a ‘Northern’ yellow warbler.

As a true bird-lover I’ve been taking notice and taking note of every new bird I’ve seen while out at sea, and naturally all of the birds I’ve seen lately from black-backed gulls to shearwaters are suppose to be out here in the open ocean searching for fish and bobbing around in the waves while resting. The yellow warbler however is not suppose to be here….and in fact being at sea means certain death for the delicate songbird as its food source is almost non-existent out here and it is ill-equipped to handle a lack of freshwater. The warbler pictured above probably hitched a ride with us following our 24 hour port call in Yarmouth, Nova Scotia. Sad to say that this warbler did in fact perish at sea despite my offerings of fresh water and bread crumbs (I was all out of their primary food which are insects!) A second warbler and a grosbeak did however find the boat as we were coming back into harbor so we hope they were more fortunate then the first stowaway.

Identification: The yellow warbler is fairly large compared to other warblers and has an exceedingly short set of tail feathers. Both sexes have a yellowish green head and back with yellow underbellies. Females tend to be a bit duller in color while males typically have brown streaks on the cheek and breast. Distribution: The Northern Warbler breeds from Alaska to Newfoundland and Southern Labrador, south to South Carolina and into Northern Georgia, and as far west as the Pacific Coast. It is also found periodically in the American Southwest. Migration: Winters in the Bahamas, Northern Mexico, Peru and the Brazilian Amazon. Diet and Habitat: In its northern and eastern distribution the warblers live in damp habitats surrounding swamps, bogs, marshes, ponds and stream or river banks. They will also feed and nest in woodland areas, meadows, and overgrown pasture lands. In the west and southwest the bird is restricted mainly to riparian habitats. Unfortunately riparian habitat is rapidly decreasing in the Southwest as are the population of yellow warblers within this region. The warbler feeds primarily on insects, but will occasionally eat berries. Listen to its song here.

Common Dolphin

Until recently both the short-beaked and long-beaked common dolphins were considered to be one species. Although much of the recent research and literature still does not differentiate between short-beaked and long-beaked, they are technically two different species. For the purposes of our survey we also did not distinguish between the two as they are nearly identical in physical appearance.

Short Beaked Common Dolphin and Long-beaked Common Dolphin

Identification: Very distinctive crisscross patterning on the sides; yellow/tan patches on the side, dark gray over the topside and pale underside. Light grey patch along the peduncle of the tail.

Max length and weight: 330 pounds and 9 feet. Males are just slightly larger then females

Diet and Feeding: Fish and squid

Migration: No organized or seasonal migration

Distribution: Widely distributed throughout the Atlantic, Pacific, and Indian Oceans as well as the Black and Mediterranean Seas. Special Note: Common Dolphins are especially active and are commonly seen doing aerobatics and bow riding. They are also extremely vocal; to such a degree that their high pitched whistles and clicks may be heard above water.

References

Collins Wild Guide: Whales and Dolphins. Harper Collins Publishers, New York, New York, 2006.

August 1, 2007April 1, 2021

Methea Sapp-Cassanego, August 1, 2007

NOAA Teacher at Sea
Methea Sapp-Cassanego
Onboard NOAA Ship Delaware II
July 19 – August 8, 2007

Mission: Marine Mammal Survey
Geographical Area: New England
Date: August 1, 2007

Weather Data from Bridge
Visibility: 7nm lowering to less then 1 in fog
Wind Direction: Southerly
Wind Speed: 3-8 knt increasing to 8-13
Swell height: 3-5 feet

The flexible Jacob’s ladder rolled up for easy storage.

Science and Technology Log

Fog has kept our sightings to a minimum over the past two days. In fact we’ve had only two sighting since my last log on July 27^th. Yet despite today’s weather forecast, the fog horn has been silenced and everyone is outside enjoying the sunshine and stretching their eyes. It is a wonder to see color other then a shade of grey! The change in weather has also brought new sightings including 3 humpback whales, a pod of harbor porpoises, 4 right whales, a minke whale and a dozen or so pilot whales (spotted by your’s truly). These sightings kept the observers busy as well as those involved in the launching of the zodiac (aka little grey boat) and the Tucker trawl. The morning sighting of the right whales prompted a Tucker trawl sampling in order to examine the copepod densities in the surrounding areas.

Dr. Richard Pace assists with deployment of the zodiac.

The trawl did yield a higher density of copepods then all of our previous trawls which where carried out in the absence of right whale sightings, however compared to their prior experiences most of the researchers thought that the copepod densities were still on the sparse side. The sighting of pilot whales brought the first launching of the zodiac boat. The goal for this expedition is two fold: 1. To attain tissue samples from some of the pods larger whales so that genetic analysis and subsequent pedigrees may be chronicled and; 2. Acquire photographic images of individual dorsal fins in an effort to establish a method of identifying individuals based on their unique dorsal fin features. Such features may include nicks, scratches, unusual scars and or color patterns. Deployment of the zodiac requires numerous experienced hands and a wherewithal for safety. First the boat is loaded with all the supplies (photography equipment, biopsy tips and crossbows, and tissue specimen jars) that will be needed for the sampling and documentation of the pilot whales. Then the crane on the back deck is used to hoist the zodiac up and over the side of the DELAWARE II. Chief scientist, Dr. Richard Pace then climbs on board the zodiac while the crane slowly lowers the boat into the water. Dr. Pace keeps the zodiac in position while a special flexible hanging ladder called a Jacob’s ladder is unrolled down the side of the DELAWARE II. All other persons enter the zodiac from the DELAWARE’s back deck via the Jacob’s ladder.

Once deployed, the researchers make final adjustments before pursuing the pilot whales.

After the little grey boat is loaded it sets off in the direction of the whales as indicated by the observers on the fly bridge, who have all the while been communicating the whales’ position to the captain of the DELAWARE who then makes sure that the ship stays relatively close to the pod. As one can imagine three-way communication between the fly bridge, the wheel house and the zodiac is critical for not only tracking the swiftly moving whales but also for the safety of all involved. Today was my day to be on the fly bridge as all of this was going on but if the weather holds and we keep seeing pilot whales then I too may get to ride on the zodiac.