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Posts tagged ‘fish’

Kelp Greenling Colour and Courtship

While diving this morning, I came across a kelp greenling couple while they were courting (Hexagrammos decagrammus to 60 cm).

In addition to being fascinated by the courtship behaviour, I was struck by the intense colouration, especially of the courting male.

Male kelp greenling. Normal colouration. ©2013 Jackie Hildering

Male kelp greenling. Normal colouration. ©Jackie Hildering

Mature male and female kelp greenlings look very different but I had never fully realized how the males’ gender specific colour intensifies during courtship.
Their bodies become much paler while the heads remain dark blue.

Courting male on left (note how much lighter the body is than the head); female on the right. © 2013 Jackie Hildering

Courting male on left (note how much lighter the body is than the head); female on the right. ©Jackie Hildering

My 1.5 minute video below shows the courtship behaviour. After that there is a photo of eyed kelp greenling eggs.

Kelp greenling eggs in a giant barnacle shell. See the eyes?! © 2013 Jackie Hildering

Kelp greenling eggs in a giant barnacle shell. See the eyes?! ©Jackie Hildering

It’s Raining Fish?!

Juvenile yellow-tail rockfish.

Recently, I noticed a lot of splashing in a tideline off Telegraph Cove, BC. I share my observations with you via the little video clip at the link below.

You’ll note that it looks like big rain drops are hitting the water.

I discovered that what was creating the splashing were juvenile yellow-tail rockfish feeding on zooplankton. The zooplankton, including a small species of krill, had been concentrated at the surface by the big tidal exchange. There had been almost a 4 metre exchange between high and low tide (more than 12 feet).

I also discovered a very unique larval fish in the tideline that day but will share that discovery in a future “The Marine Detective”.

Click here for the video of the yellow-tail rockfish feeding in the tideline.

Enjoy!

Who’s Your Daddy?

Scalyhead Sculpins are a tiny fish but the males have a giant parenting role (species Artedius harringtoni).

I found what I believe were this species’ eggs while guiding a recent beach study (Port Hardy, BC).

To share this information, and my photos, I’ve tried something new. Below, you’ll find a slideshow that I have narrated to explain how Scalyhead Sculpins are super dads.

Yes, that’s right, you get to hear my voice this week (oh-so-human stumbled speech and all!). Please realize I am speaking as I would to a +/- 10 year old.

Manta Ray Magic – Fiji

In December of 2009, I had the extraordinary privilege of seeing manta rays while diving off Kaduva Island with the dive crew from the Matava Eco-Resort. It is thanks to the environmental ethic of this team that these dives are very controlled to make sure the animals are disturbed as little as possible.

The video allows us to share all the observations listed below as well as giving you the chance to laugh when you hear my underwater screams of joy when the mantas break from their feeding behaviour, get into a formation of 5 animals and swim by us 4 times! I didn’t even realize I was making these sounds but my dive buddy was there behind me, capturing it on video.

The video shows:

Holy manta rays are big! They are the biggest rays in fact; up to almost 7 m across and more than 1,000 kg. The ones we saw are probably about 4 m across.
They are very “alien” looking animals. They feed on plankton and small fish and can scoop more food using the two big paddle-shaped flaps (“cephalic lobes”) that are just to the inside of their eyes. You will see from the murkiness of the water that it is thick with plankton. The circular diving pattern of the mantas is believed to help them concentrate the plankton.
That manta rays have a relatively short tail for a ray, no stinging spine and you’ll see one animal in the video that has had their tail shredded off, likely by a tiger shark.
That sometimes there are remoras attached to the manta rays. These fish may help in removing parasites and have the benefit of transportation, being less visible to predators and possibly getting some scraps as snacks.
That mantas are incredibly graceful, having very flattened bodies and big wing-like fins.
They can be told apart as individuals. Of course the one with the shark injury is easy to tell apart from the others. There is also one that has had its left fin tip bitten off. But if you look even more closely, you’ll see that each animal has unique markings on their upper and undersides. We passed on our photographs and video for research but, even though they are easy to tell apart, so little is known about them.
They are intelligent and coordinate their movements. This is what I found the most fascinating of all, how they knew to all get into a line at the same time and as each of them came by, they were observing me. They pivoted their eyes back to get the longest look possible at the strange creature who couldn’t stop from screaming out in sheer amazement.