[Coral-List] Parrotfish and coral
Quenton Dokken
qdokken at gulfmex.org
Fri Feb 24 11:16:22 EST 2017
Greetings All,
Another interesting occurrence in the Diadema die off occurred in the Gulf
of Mexico. Urchins at the Flower Garden Banks were hit hard. But, ~60
miles inland at Stetson Bank, in temperate waters, there was no die off.
Quenton Dokken,
361-442-6064
-----Original Message-----
From: coral-list-bounces at coral.aoml.noaa.gov
[mailto:coral-list-bounces at coral.aoml.noaa.gov] On Behalf Of Douglas Fenner
Sent: Thursday, February 23, 2017 4:18 PM
To: Eugene Shinn <eugeneshinn at mail.usf.edu>
Cc: coral-list at coral.aoml.noaa.gov
Subject: Re: [Coral-List] Parrotfish and coral
Gene,
Thanks! As for African dust being the cause of the Diadema dieoff
throughout the Caribbean and Florida in 1983, there is one detail of the
dieoff that I wonder if African dust can explain. The dieoff began in
Panama and took an entire year to move around the Caribbean. The sequence
it moved in matches the direction of current patterns. At individual
locations, the dieoff took only about 10 days. How can African dust
possibly account for that pattern? Did African dust first hit Panama, and
then move around the Caribbean following water current patterns? Why wasn't
the dieoff synchronous across the Caribbean, and why was the dieoff complete
at one location long before it even appeared at another? Is there
documentation of the African dust reaching the Caribbean in that pattern?
Wouldn't the dust reach the eastern islands of the Caribbean and then move
west? Isn't that the direction that the wind usually moves? That's how the
dust gets from Africa to the Caribbean. How could African dust get to
Panama first before reaching the windward islands in the eastern Caribbean
many months later??
Cheers, Doug
On Fri, Feb 17, 2017 at 8:49 AM, Eugene Shinn <eugeneshinn at mail.usf.edu>
wrote:
> Thanks to all who have weighed in and posted comments on the subject
> of parrotfish herbivory, ancient fishing, and coral growth. I learned
> a lot. The paper by Cramer, K. L., (2013) /History of human occupation
> and environmental change in western and central Caribbean Panama,/
> /Bulletin of Marine Science /89m (4) 955-982 Is an outstanding read.
> The paper is well documented, and shows how heavily populated central
> America was in pre Columbian times before the Spanish came and
> obliterated more than 90 percent of the population. And yes, they did
> eat fish but most of the damage to coral reefs then as now was mainly
> related to agriculture and runoff. To feed fish to the once large
> population using only fish hooks made from turtle shell still seems a
> bit of a stretch, especially herbivorous fish. How does one bait a
> hook with algae? Most likely the ancients used spears and nets along
> with fish traps. Traps are easy to construct from native materials and
> such traps are still made and used today in various parts of the
> Caribbean. Traps will certainly capture parrotfish while even modern metal
fishhooks seldom catch these fish.
> Other postings point out that parrotfish remove algae on dead
> coral or other surfaces thus preparing the surface for coral
> recruitment. This has long been the accepted standard explanation and
> surely applies in many areas.
> Hanna Rempel (off line) pointed out that indeed certain
> parrotfish do bite live coral. I agree and have watched them doing so.
> I once spent a day on Looe Key reef watching parrotfish taking bites
> from large Montastraea heads. It was an especially calm day and there
> were small piles of parrotfish poop resting on the tops of several
> live coral heads. Unfortunately I was not there long enough to watch
> for an effect the defecated sand might have on the coral. Of course
> waves eventually swept the sandy material off or the coral polyps
> removed the sand. What was obvious, however, were many 3 to 5 cm dead
> spots supporting algae and/or infected with black band disease. Bite
> marks suggested that parrotfish made these areas. I had never seen
> parrotfish bites in infected with algae before. Possibly there was an
> overabundance of parrotfish because the reef is protected.
> Now back to my earlier comments concerning Carysfort reef in the
> Florida Keys. I have been taking serial photos there for the past 56
> years. Three summers ago I spent a day there with Phil Dustan who had
> done the most significant monitoring work there in the 1970s when it
> was a beautiful live /Acropora/ reef. At Carysfort all the /A.
> palmata/ and virtually all the backreef /A. cervicornis/ was dead and
> had been converted to rubble. Parrotfish were have a field day. They
> were biting coral that had died back in the mid 1980s. There had been
> virtually no recruitment there in the 30 or more years since. At the
> rapid rate the parrotfish and roving bands of blue tangs are munching
> the dead coral an abundance of reef sand has been created. That reef
> sand no doubt contains fish teeth. Now spring ahead a hundred years
> and assume the coral are flourishing and take some cores of the reef.
> Where would the parrotfish teeth be? Would they not be in the sediment
> associated with the period of time when the reef was dead and plenty
> of algae to eat? If you counted the abundance of the teeth in the
> sandy part of the cores would you conclude the parrotfish had killed
> the reef? Or would you assume the fish died thus causing the corals to
> die? Or was it pollution/disease/or climate change or something else,
> possibly African dust that killed the reef?
> That parrotfish herbivory is not needed to stimulate coral reef
> growth has been shown by others, Auchley A. McField MD. Alverez-Filip L.
> (2016) /Rapidly increasing macroalgal cover not related to herbivorous
> fishes on Mesoamerican reefs/. PeerJ 4:e2084
> <https://doi.org/10.7717/peerj.2084>their observations on the Belize
> reef tract are well documented.
> Kauffman has suggested hurricanes might kill and cause rubble to
> become algal infested. That could also lead to parrotfish increases.
> That event was well documented in Jamaica.
> When hurricane Donna decimated Grecian Rocks reef in 1960 the
> reef did not become algal infested. In fact most broken fragments of
> branching corals began growing and the reef area expanded. We
> documented the storms effect. (Ball, et al 1967), and the recovery (Shinn
1976).
> The same happened in 1965 when Betsy decimated the same reef. Again
> the reef recovered. However, the reef did not recover after 1990 when
> hurricane Andrew swept though the upper keys. Something had changed
> and algal infestation became rampant. There were no longer /Diadema/
> to remove the algae (they had died in 1983) but there were sill
> abundant parrotfish. Some time ago I proposed that the 1983 increase
> in algal turf was related to the Caribbean-side demise of /Diadema/
> and the effects of African dust. (Lessios, et al 1984) had shown that
> /Diadema/ demise was Caribbean-wide. Monitoring of African dust by Joe
> Prospero showed the dust had blanketed the Caribbean in 1983; He had
> been monitoring dust in the eastern Caribbean since 1965 and showed
> 1983 to be the peak year of dust flux to the Caribbean. (Shinn, E. A.
Smith, G.
> W., Prospero, J. M, Betzer, P., Hayes, M I, Garrison, V. Barber. R T.,
> 2000, /African dust and the demise of Caribbean coral reefs/:
> Geological Research Letters, v. 27, P. 3129-3132). Many will say it
> was sewage and increasing population in the Keys that cause demise.
> However that does not explain why the same events were happening
> simultaneously to reefs around small islands throughout the Caribbean.
> Dust flux remains high and a recent unfunded and unpublished
> preliminary testing of African dust collected from the air showed it to be
lethal to A/. cervicornis/.
> Why it is toxic is not known but our earlier work at USGS showed that
> in addition to the nutrients iron, and phosphate, the dust
> coincidentally contains (copper, mercury, arsenic, radiogenic
> beryllium 7, lead 210, various pesticides, and approximately 200
> viable species of bacteria and
> fungi) Possibly some of these ingredients can affect coral growth. But
> that's another story. Hopefully some day someone will do the work
> needed to determine exactly what is in the dust that affects coral and
> people) but do not expect any government agency to fund the research.
> Everyone who has written a proposal to do so has been turned down. Is
> more study needed? You bet! Gene
>
> No Rocks, No Water, No Ecosystem (EAS)
> ------------------------------------
> -----------------------------------
> E. A. Shinn, Courtesy Professor University of South Florida College of
> Marine Science Room 221A 140 Seventh Avenue South St. Petersburg, FL
> 33701 <eugeneshinn at mail.usf.edu> Tel 727 553-1158
> ---------------------------------- -----------------------------------
>
> --
>
>
> No Rocks, No Water, No Ecosystem (EAS)
> ------------------------------------
> -----------------------------------
> E. A. Shinn, Courtesy Professor
> University of South Florida
> College of Marine Science Room 221A
> 140 Seventh Avenue South
> St. Petersburg, FL 33701
> <eugeneshinn at mail.usf.edu>
> Tel 727 553-1158
> ---------------------------------- -----------------------------------
>
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--
Douglas Fenner
Contractor for NOAA NMFS, and consultant "have regulator, will travel"
PO Box 7390
Pago Pago, American Samoa 96799 USA
phone 1 684 622-7084
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