[Coral-List] Lionfish in the news
douglasfennertassi at gmail.com
Sun Feb 2 23:34:41 EST 2014
I took a look back at Lessios et al. (1984) and it appears to me from
the map showing different dates that the Diadema disease hit different
locations, that the disease spread in both directions from Panama, going
clockwise, north from Panama, then east to the Bahamas, then southeast to
reach the Windwards, and at the same time it spread east from Panama along
the coast of South America. It appears to have reached the Windwards going
both directions, at about the same time. It is true that prevailing
currents in the Windwards move westward. However, as shown in the Lessios
et al. map, there are boundary currents along the South American coast that
go in the opposite direction to the main current offshore. Another thing
to keep in mind, is that in many places in the world, the average or mean
or net current may go one direction, however variability over time is
large, and at different times small parts of the water mass may move in a
variety of different directions. In places with the strongest currents
like the Florida Current, that is likely to be very rare if it occurs at
all, but most other places it is common. Net effect is that a water-borne
pathogen can sometimes move in directions that don't seem likely if you
just look at the direction of prevailing currents, because part of the time
the water isn't moving that direction.
Lessios et al. document a great deal of detail about how the spread
followed water currents. The mass of evidence showed that it followed
water currents, including to all of the Windward islands except Barbados.
Barbados got it a couple months before the rest of the Windwards. They
also talk about the boundary currents, and provide details that fit with
dispersal along island coasts that way.
If you re-read the Lessios article, Gene, you'll see why most
scientists accept that the pathogen followed the currents, the data have so
many details that are explained in detail by the currents that it is
obviously well supported. African dust can't explain why it spread in all
these detailed patterns. African dust would likely arrive at the eastern
end of the Caribbean first, and move in a very broad front in a few days
westward across the Caribbean, either infecting all areas at the same time,
or with very little delay from east going west. That is very clearly NOT
the pattern that it happened in. Take a look at the Lessios paper.
The spread of Lionfish from Florida southeastward appears to me to be
quite similar to the pattern of Diadema spread shown in Lessios. The coral
Tubastraea coccinea followed a pattern of spread very similar to that of
the Diadema disease (Fenner and Banks, 2004). The principle difference was
in the speed of the spread, Diadema spread throughout the Caribbean in one
year, while Tubastraea coccinea took about 60 years. That is likely
because the spread was done stepping-stone style, and it took only about a
week for the Diadema to die and presumably release a new batch of pathogen,
while it takes about 18 months or so for Tubastraea to grow large enough to
reproduce (Fenner and Banks, 2004). It appears to me that the rate of
Lionfish spread is slower than Diadema, but faster than Tubastraea. Your
African dust hypothesis ("just dropped out of the prevailing trade winds")
doesn't appear to me to be able to explain any of these things, in fact if
you predict the way it would spread from your theory, it appears to me that
the actual reported patterns are strong evidence against your theory.
Tubastraea and lionfish clearly didn't fall out of the tradewinds, yet they
followed the same pattern of spread.
Lessios HA, Robertson DR, Cubit JD (1984) Spread of* Diadema* mass
mortality through the Caribbean. Science 35: 335-337.
Fenner, D. and Banks, K. 2004. Orange cup coral, *Tubastraea coccinea*,
invades Florida and the Flower Garden Banks, Northwestern Gulf of Mexico.
Coral Reefs 23: 505-507.
On Sat, Feb 1, 2014 at 6:30 AM, Matthew Johnston <johnmatt at nova.edu> wrote:
> It is an interesting point you bring up about the southern end of the
> Windward Islands. A colleague and I published a 2011 paper on the spatial
> pattern of establishment of lionfish throughout the Atlantic and Caribbean.
> The findings included the results of a cellular automaton computer
> modeling study, the algorithm of which was developed based on reported
> sightings of lionfish to the USGS NAS database. The model predicted that
> the southern of the Windward Islands was indeed one of the last places
> where establishment would occur in the Caribbean, and this seems to be the
> pattern that lionfish have followed. You mentioned the fact that
> larvae/eggs would need to move up-current to reach the windward islands,
> and this is exactly what our modeling scenario revealed, based on mean
> average currents for the whole Caribbean basin. Here is the citation for
> that paper and a follow-up if you wish to read more:
> Johnston, M.W., Purkis, S.J. (2011) Spatial analysis of the invasion of
> lionfish in the western Atlantic and Caribbean. Marine Pollution Bulletin
> 62 (6), 1218-1226.<
> Johnston, M.W., Purkis, S.J. (2012) Invasionsoft: A web-enabled tool for
> invasive species colonization predictions. Aquatic Invasions 7(3), 405-417.<
> By 2009, the lionfish invasion was in full swing, and while they surely
> arrived a bit before then in the Windwards, the delay between actual
> establishment and reports was probably not as long because people were
> actively monitoring for them. The major currents in that region run east
> to west and so movement southeast would be difficult, according to our
> modeling effort.
> I wonder if the Diadema and Acropora pathogen were driven less by
> currents, but rather spread radially, more by local contact than
> water-borne and long distance distribution of disease propagules. The
> Trade Wind theory is also an interesting explanation. I don't claim
> expertise on any of these pathogens, but if they were spread solely by
> currents, I agree that they would have a tough upstream journey getting
> from Panama to the Windwards, unless perhaps some major current switching
> events, such as a hurricane, occurred during that time.
> Matt Johnston
> Research Scientist/Scientific Computer Programmer
> National Coral Reef Institute
> Nova Southeastern University Oceanographic Center
> 8000 N. Ocean Drive, Dania, FL 33004 USA
> johnmatt at nova.edu<mailto:johnmatt at nova.edu>
> 954.262.3641 (office, CoE #506)
> 954.205.8007 (cell)
> Date: Thu, 30 Jan 2014 15:04:26 -0500
> From: Eugene Shinn <eugeneshinn at mail.usf.edu<mailto:
> eugeneshinn at mail.usf.edu>>
> Subject: [Coral-List] Lionfish in the news
> To: "coral-list at coral.aoml.noaa.gov<mailto:coral-list at coral.aoml.noaa.gov>"
> <coral-list at coral.aoml.noaa.gov<mailto:coral-list at coral.aoml.noaa.gov>>
> Message-ID: <52EAB04A.8080406 at mail.usf.edu<mailto:
> 52EAB04A.8080406 at mail.usf..edu>>
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> It was interesting reading through the most recent postings on
> Lionfish. In one of the websites I noted (in the 2009 USGS map of lionfish
> sightings) that they had not yet reached the Windward Islands or at least
> had not been observed there yet. However, a more recent map someone
> working on Lionfish showed me indicates that they are now in the Windward
> Island but have not yet made the jump to the southern end of the island
> chain. Nevertheless, considering how long they have been in the Caribbean
> they should have reached those islands long before 2009.
> If they really were not in the the windwards islands by 2009 there was a
> good reason why. They, or their eggs and larvae, would have to swim against
> a strong East to West current. But that's no problem. Many researchers had
> no problem accepting the hypothesis that what ever decimated Diadema in
> 1983 started around the Panama Canal were not stopped by the current and in
> less than a year had reached the Windward Islands. Also, the Caribbean-wide
> demise of Acroporids (including the Windward Islands) occurred during the
> same year (1983). Humm. Again it is possible that Lionfish did make it to
> the Windward Islands long before 2009 but just had not been observed yet.
> It would be interesting to know when they actually did reach the islands.
> Clearly the pathogen that caused Diadema and Acroporid demise made the
> trip. I wonder if it could be that the Diadema and Acropora pathogen, along
> with the soil fungi that caused the sea fan disease, just dropped out of
> the the prevailing trade
> winds in 1983? Something to ponder.
> Nevertheless I suspect we will be discussing Lionfish immigration for as
> long as congress discusses immigration reform.
> Hopefully they will just die off from natural causes, the lionfish that
> is. Gene
> No Rocks, No Water, No Ecosystem (EAS)
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> University of South Florida
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