I would have thought, due to the danger it poses to people, there would
be a spray that is kinder on the environment
and a death knell to the red-tide. One would think lime water - not far
away from coral - or something that disrupts
the cycle of the Alga Bloom. We can only hope that a University would
assign a Grad Student work on a solution.
Finding one that saves lives - some of the fish are collected and sold
before it is detected... I had (he passed) a fraternity brother
that went to the coast for a fishing trip and ate dinner in a beach (and
semi-famous) Fish house. He never left town...
I thought the red-tide was a clam danger. Not to eat with months
containing .....
Snails feed on dead fish if they touch the bottom. Also clams have
themselves exposed
then seeking food. One would think they would be attacked just as well
as a fish.
Martin
On 8/26/2018 6:21 PM, Ken Piech wrote:
> Dear members,
>
> During our most recent visit to Sanibel, the island was experiencing the deadly effects of a Harmful Algal Bloom on its marine animal life. There have also been harmful effects on visitors and on the island economy. As many of you know, high concentrations of Karenia brevis and its brevetoxin, aka red tide, https://tidesandcurrents.noaa.gov/hab/gomx.html have been present in the coastal waters of southwest Florida for several months. During the past month the City of Sanibel has removed from its beaches, canals, and surrounding waters hundreds of tons of dead fish as well as many dead turtles and mammals. The situation has been well described by the local & national news media and on the City of Sanibel website, http://www.mysanibel.com/Departments/City-Manager-s-Office/News (see Status Reports #1-19) and will not be further discussed in this post, except for my observations on its effects on the local marine mollusks.
>
> At Lighthouse beach on the intertidal sand and in the tide pools, there were thousands and thousands of fresh dead Bulla occidentalis A. Adams 1850, aka striate bubble shells, many/most still containing a portion of the dead soft body. I have not previously observed such a large number of fresh dead B. occidentalis. Although the beach clean-up has removed almost all of the dead fish, it has also removed most of the shells and other interesting sea life that washes up on the island. It is unusual to see the Sanibel beaches so “clean.” During the minus low tides, we collected several hundred, fresh dead Neverita delessertiana (Recluz in Chenu, 1843) and three fresh dead Neverita duplicata (Say, 1822) on one small sand/mud flat on the Pine Island Sound side of Sanibel Island. We saw no live N. delessertiana. About 10% of the fresh dead N. delessertiana still contained the dead mollusk, including the operculum. We froze a number of the specimens containing animals for possible, future studies.
>
> There were also many, fresh dead Chione elevata (Say, 1822) and Tellidora cristata (Récluz, 1842). Although the numbers of these two fresh dead bivalve species appeared to be increased (as compared to the number we usually observe), the increase was not near the same magnitude as the number of fresh dead N. delessertiana, which was about 100 times the number that we usually see on that sand/mud flat. At the same time we also observed both live and dead Strombus alatus Gmelin, 1791, Melongena corona (Gmelin, 1791), Sinistrofulgur sinistrum (Hollister, 1958), Americoliva sayana (Ravenel, 1834), and Macrocallista nimbosa (Lightfoot, 1786). The relative numbers of these live and dead mollusks were similar to what we have previously observed.
>
> We have collected shells on the same small sand/mud flat many times (>30) during the past ten years and have not previously observed the large number of fresh dead, individual species of mollusks, while other mollusk species appear to be less affected or unaffected. This post will limit its focus to the fresh dead N. delessertiana. The chronologic association of the red tide beginning 2-3 weeks prior to the collection of the fresh dead N. delessertiana raises the question of causality, either direct or indirect.
>
> To date, my brief literature search has not identified any direct negative effects of brevetoxin on mollusks. I have found numerous references of red tide and brevetoxin killing many marine animals, being concentrated in filter feeding bivalves and causing a variety of human diseases. The references discuss the accumulation and concentration of the brevetoxin in the “tissues” of bivalve mollusks, but do not discuss any direct, deleterious effects on these mollusks. Perhaps I have just overlooked a large body of research on this subject. It seems unlikely that the negative effects of Karenia brevis and its brevetoxin on mollusks have not been previously well described.
>
> I have already discussed this subject privately with several members of Conch-L. Has anyone else on this list serve observed red tide appearing to kill mollusks? Would anyone be able to provide references on the morbidity and mortality of brevetoxin on mollusks, either bivalves or gastropods or both? You can send the references to Conch-L or to my personal email address, whichever you are most comfortable doing. My investigation of this apparent die off of N. delessertiana has raised far more questions than I have asked in this single post. Any information/assistance you can provide will be much appreciated.
>
> Cheers, Ken
>
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