This is a long, narrow inlet that cuts up through Halifax. Even on windy days it's calm and protected from the open-ocean swell. There are several spots to access the water along it's length, but according to the chart, the steepest and deepest spot (60 feet) is in the middle, just off Sir Stanford Flemming Park. There is a point of land with an old tower (Dingle Tower), a boat launch ramp, a water-side walkway and plenty of parking. The locals usually don't consider diving here, saying it's "muddy" and "dirty", but when I looked down into the water from shore, the visibility seemed much better that the more open-ocean spots. Much of North-West Arm is frozen over at this time of year, but off this park it was always mostly free of ice. I entered in front of the parking area and explored around the point below the tower. The shallows was a bed of mussels turning into a gentle slope of small rocks and larger rocky out-croppings. There were quite a few plumose-type anemones, small green urchins, old pop bottles and all the usual junk that you find in the shallows off a busy park (car keys, a bike frame, a blackberry, etc.). This area was mostly free of silt, but as I swam deeper, the bottom was covered with deep mud. There were still boulders and rocky out-croppings covered with those anemones, as well as long, stalked-type kelp swarming with various kinds of nudibranchs. Most of the kelp was around 15-25 feet deep. At around 35 feet deep, I was surrounded by a garden of strange sponges growing on the rocks and scattered over the mud. There were several species of sponges (mostly yellow-coloured) along with more plumose anemones, tube-dwelling anemones and old pop bottles. I swam out to around 55 feet deep where there seemed to be less rock and more mud. I saw a strange patch of pink on the mud. When I came closer, I could see it was moving. It was a pile of tiny copepods(?) or sea-lice swarming over a dead crab. Creepy.
I did around 6 dives here. I kept coming back because it seemed to have much more life than the other, more popular dive spots. Most of the more exposed sites have just coralline algae-coated rock with very few anemones or sponges. The variety and abundance of invertebrates here in North-West Arm was a nice surprise. Most of the fish that I saw while I was in Halifax were here (two!). One looked like a small, foot-long cabezon and the other one was some other kind of tiny sculpin. I even saw a big lobster hiding in a deep crack under a boulder. The visibility wasn't great here by B.C. standards, but it was consistently better than most other local spots. It probably averaged 10-15 feet with 20 feet on one good day and 5 feet on a bad day.
