near shore corals failing ? (Kahalu'u park south of Kona)

[scubabdref]

just got back a couple weeks ago and while had a wonderful trip, can see how much the environment is under threat. Dived on Kauai and Kona, most visible was retreat of live reef while snorkeling at Kahalu'u park south of Kona. We were there in 2006 and 2011, both times we were probably there at high tide, turtles right up to shore, coral "pillows" covered with live coral, lots of fish, vibrant. We were there an hour after high tide this time, the fish were reasonably plentiful, but the perceptible health of the coral was a lot less. Bleaching on the tops of the ring corals (sorry, I don't know the correct terms, so I'm using descriptive names) and far fewer live outcroppings. Lots of dead coral (staghorn). Covered with dead organic matter

We saw the same on our dives, the fish are there, but noticeably fewer, and the reef is not healthy, signs of bleaching, and lots of dead coral. Is this correctly observed, is it widespread across the islands, and are the causes as "simple" as ocean warming, a recent temp spike producing a current bleaching event, too much organic runoff, too many tourists, or... Haven't been underwater in the islands in 4 years, and it looks like we can see environmental decay before our eyes based on our memories.

Mahalo nui loa and aloha !

 

[King_of_All_Tyrants]

All I've had real good direct views of has been Honaunau; I've gone there about annually for the past few years. (also first place I ever saw the sun set into the sea, when I was 8 years old, a sight I will always remember, and a pilgrimage I repeat usually each time I go to the Big Island).

When I went about a year ago the situation was worse than in previous years. Lots of dead "finger coral" (Porites compressa), though it looks like there was a decent amount of boulder coral growth (Porites lobata). And the "staghorns" (Pocillopora) - that's site specific. They can grow well and quickly, but sometimes they die down if the alkalinity/salinity/etc. isn't perfectly right (in my experience). I'm told that oil leaking from the parked cars might be a problem. I'm more of the opinion that runoff is the main problem at Honaunau.

El Nino has been a general problem. The former Kapoho tidepools had big brown plate corals (Montipora sp.) with 10-50 bleaching, mostly (I was told by a UH-Hilo scientist) due to El Nino from a few years before, and a then-unidentified probable illness.

Also note that this is anecdotal; you can't extrapolate from one site. For instance, Honaunau's yellow tang population has appeared to my eye to be less, BUT Kona coast yellow tang counts are doing well otherwise, IIRC they are now about the highest that they've had since they started doing surveys 20-some years ago. (controversial issue, though).

 

[FishCity]

We started noticing declining coral health and fewer fish almost 3 years ago. West Hawaii has had bad bleaching in our observations esp shallow water
http://bigislandnow.com/2018/03/02/researchers-create-first-map-showing-impact-on-hawaii-reefs/
Coral possibly on the rebound: Small signs of new growth evident along the Kohala Coast - West Hawaii Today

 

[scubabdref]

Mahalo nui loa for your updates ! The second cite lays it out, I guess this episode started in 2015. Let's see what comes back (and work to stop climate change in the meantime).
Aloha!