28th January 2009 filming a humpback in the water, two more fluke id photos and humpbacks singing! Print
Written by Andrew Stevenson   

 

Two new flukes

                                          

Fisherman Kevin Winter phoned in early with humpbacks feeding on the edge a mile west of South West Breaker. With Michael Smith as captain, we set out with Kevin Horsefield, Kelly Winfield, Chloe Kempe and myself on Sea Slipper on a beautiful sunny and calm day. We eventually spotted two whales off the point at Sally Tuckers exhibiting typical feeding behaviour fluke diving for intervals of at least 11 minutes in 100-130 feet of water as they moved north along the edge from the point at Sally Tuckers. An interesting aspect of their behaviour was the observation that they often made fluke dives at exactly the same time, in perfect synchrony. Mid-afternoon the two whales cruised on a steady heading and at a consistent speed of 5 1/2 knots towards Challenger. By setting a course parallel and going slightly faster we were able to stay ahead and to the side of them. On these occasions the whales diverted towards us and when we were stationary surfaced beside or immediately behind us. After getting in the water a couple of times with the engine off and listening on the hydrophone and hoping to attract them to us, one did swim under me and circled fifteen feet below several times before heading off. This seemed to be an older whale and had many white scars on its dorsal fin, an indication that it was a male.But looking at underwater video footage of a mother with a calf here in Bermuda, I see the female has the same amount of scarring on the dorsal fin, so this could be a male or female with a smaller whale.

The scarred back belonged to the fluke on the left at the top.

The water was warm, 71 degrees and it wasn't cold even with just a 3mm wetsuit on. We followed or were parallel to the whales to the eastern edge of Challenger where they made an abrupt left hand 90 turn on the edge of the Challenger Banks, presumably to feed. We left them at 3.30 and Kelly sighted another whale spout on the South East side of Challenger. On the way back Kelly sighted another whale to the south.

On the way out we listened with the hydrophone at South West Breaker where I could just make out the sounds of a humpback. At Sally Tuckers the sounds were slightly louder and as we crossed the canyon between ST and Challenger the humpback singing became more pronounced. Just before we headed back we listened a last time and I would guess the much louder sounds were from the crown of Challenger, as they were last season. But we also heard something else too; I thought it might be dolphins but we hadn't seen any and Kelly began to think that it didn't sound like a dolphin. It was a higher pitch, and sounded like what you might expect a baby humpback to sound like. Baby humpbacks definitely vocalize so could we hear the baby whale Kevin had seen?

For Kelly Winfield's detailed notes on today's expedition and Dr Wolfgang Sterrer's analysis of a 23-35 pound yellow fin tuna's stomach contents taken on Challenger a week ago, including numerous finger-sized shrimp, see below. 

      

 

Kelly Winfield's notes on today's expedition: 

Weather Conditions
Winds: South West  at 5 – 10kts
3 – 6ft Swells outside the reef line
Slight chop

Left Watford bridge at 10:00am

Plan: Head to South West breakers (Two whales already reported a mile from Southwest)
then head out towards Sally tuckers then to Challenger Banks.

Passing South West Breaks at 10:45 began heading out towards Sally Tuckers

Hydrophone placed in water at 11:00am - Heard distant whales

Hydrophone out; continue on towards Sally tuckers at 11:15am

Hydrophone In at 11:55am Whales once again can be heard but louder.

12:05 First sighting; 2 whales
GPS 32° 11 667° 130 Feet

 Dove at 12:06. 11 minutes pass before next breath at 12:16 then dove again at 12:17pm

12:23 whale comes to surface; No breath dorsal fin spotted and bubbles seen, whales disappear from sight with no blow.

12:42 two whales surface at surface for 4 minutes dove at 12:46
140 ft of water animals fairly stationary.

13:00 Whales Surface 135 ft GPS 32°n11 598°

13:02 dove 125Ft 8 minutes

13:10 animals resurface only one blow seen

13:25 Hydrophone in. Whales are heard much louder than previous

13:30 Whales at Stern 13:32 Whales dive 13:35 Andrew in water 250ft

13:40 Whales at Bow 13:45 Whales Dive and Andrew out GPS N 32° 11. 598°

13:55 Whales off Bow dove at 13:56 14:01 Whales Spotted close to stern

14:02 Andrew in Whales under boat Andrew filming-     Whales disappear

14:22 Whales spotted off bow Andrew back in boat

 14:25 Continue on to Challenger

 15:23 Distant Blow seen East off Challenger

 15:28 Whales seen off Stern 15:35 KW in water

 15:45 Whales seen off Bow, KW back in boat

 15:47 Continue on towards Challenger banks

16:00 Whales spotted on port side moving in same direction as boat
16:04 Whales dive 16:13 Whales off Stern still moving at good speed

16:23 Whales off Bow

16:30 Boat stop Hydrophone in water; Whale vocals loud with low grunts  and higher chirps.

16:35 Boat turn around head for shore whales seen at Stern heading towards Challenger

On route back to Shore whale Spout seen eastwards of Challenger as well closer to shore.

Back to Watford Bridge by 17:55.

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Stomach content of a Yellow Fin Tuna caught by Kevin Winter, January 26, 2008, at Challenger Banks on January 17th 2009

 

About 5 lbs of frozen stomach content were defrosted on Jan 28, and examined by W. Sterrer and C. Flook.

 The bulk consisted of fish, most of which was digested beyond species identification.

  1. Among those that could be identified were a number of Sardinella anchovia (‘Chovy) and Harengula humeralis (Pilchard), which are commonly used as chum bait.
  2. Possibly also originating from bait were one specimen each of Hemirhamphus bermudensis (halfbeak) and Decapterus macarellus (Ocean robin); the latter often being used as live bait.
  3. Other fish species:             One small Xantichthys ringens (Sargassum triggerfish), which is usually associated with floating Sargassum;             one Myctophum sp. (Lantern fish), and five Gonostoma sp. (Bristlemouth). The two latter, which are deepwater species, could have been caught by the tuna diving, or at night when these fish come to the surface.
  4. One small teuthoid squid.
  5. At least 30 red decapod shrimps, apparently all belonging to the same species.