DEPARTMENT OF COMMERCE

BUREAU OF FISHERIES
HUGH M. SMITH, Commissioner

MORTALITY OF FISHES ON THE
WEST COAST OF FLORIDA

By HARDEN F. TAYLOR
Scientific Assistant, Bureau of Fisheries

APPENDIX III TO THE REPORT OF THE U.S. COMMISSIONER
OF FISHERIES FOR 1917

Bureau of Fisheries Document No. 848

PRICE 5 CENTS

/} Sold only by the Superintendent of Documents
fae | Government Printing Office, Washington, D. C.

WASHINGTON
GOVERNMENT PRINTING OFFICE
1917

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CONTENTS.

Page.
ieMinenr nie Mnvestipniwonlel os. 9S PP 8 EV NO AS 5
epimrunniie disaster in) UO1G:.- 25 aes Pare. SAR. EL tks 5
2g SPER ICN ATP Ce ee a Ye ee SP a 8
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Petrino Or SpOCinGNR. /o..+2. 22 ss.c acess ect doacacees scout ees dig
Discussion of possible causes of this and similar disasters in other parts of the
VELL OS oS 9 SE Oe Oe ee ne a ee, eR En AN: Bs a 12
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MORTALITY OF FISHES ON THE WEST COAST OF FLORIDA.

By Harpen F. Taytor, Scientific Assistant, Bureau of Fisheries.

OCCASION FOR THE INVESTIGATION.

Repeatedly in the past 75 years reports have come from the west
coast of Florida of “ poison water,” which killed fishes in large num-
bers, and also, according to some reports, other animals, notably
sponges. The reports and references are too fragmentary to give an
accurate record of the distribution of the mortality, but collectively
they clearly indicate that all the keys from Key West nearly as far
north as Cedar Keys have been visited by this plague, and that it
occurred in the years 1844, 1854, 1878, 1880, 1882, 1883, 1908, and
finally in 1916.

REPORTS OF THE DISASTER IN 1o16.

In October and November, 1916, the mortality recurred in severe
form, the first visitation since 1908. Numerous descriptive reports
were received, from which the following significant points were
summarized :

Fishes of a great number of species were noted dead and dying;
the air was charged with a suffocating gas, which not only occasioned
severe discomfort to man and other air-breathing animals, but irri-
tated the air passages, producing the symptoms of colds. This gas,
while exceedingly irritating, had no odor. The fishing smacks which
are equipped with “wells” or openings through to the water in
which live fish are kept report that the whole catch died while the
smacks were en route to port; the normal color of the water had
given way to water of different color, variously described as “ black
streaky,” “amber,” “ olive,’ and “red”; the white paint of certain
houses near the water was temporarily blackened, apparently by
gases from the enormous number of dying fish. Some local observers
found fish dying in the sounds; others noted them in the passes and
in the Gulf to a distance of 45 miles out, but the abundance of fish
in any locality varied from day to day. The reports of the order

5

6 MORTALITY OF FISHES, WEST COAST OF FLORIDA.

in which the species appeared are not consistent, so it is assumed that
there was no particular succession of species. The abnormal condi-
tions seemed to be moving southward, occurring at Boca Grande on
October 3 and 18, at Captiva Pass about the middle of October, at
Blind Pass about October 20, at San Carlos Pass about November 1,
and dead fish were first seen at Big Marco Pass on November 5.
Captiva Pass is 7.5 statute miles south of Boca Grande Pass; the
others are, respectively, 16.5, 27.75, and 67.75 miles to the south of
Boca Grande Pass. The captain of the steamer Roamer, of the
Florida Shellfish Commission, reports that dead fish were seen as
far south as Cape Romano, about 128 miles south of Boca Grande.
The death of two persons in Fort Myers, Fla., in November, was
attributed to the eating of some of these dead fish.

The following letters from George H. Skermer, deputy collector of
customs at Boca Grande, describing the phenomenon, merit reproduc-
tion here. Letter dated October 22, 1916, reads:

I wish to call your attention to an unusual phenomenon which has occurred
on the Gulf coast during the past month, and which, so far as I am able to
ascertain, has extended on the north to Sarasota and south to Naples, west-
ward, from 15 to 20 miles.

About October 38, large quantities of what are locally known as “ red-mouth
grunts” began to come ashore. These fish were normal in appearance, with the
exception that many showed a tendency to have the eyes almost forced out
of their sockets. The early morning of the third the Gulf was covered with
these fish as far as the eye could see. Later in the day many other varieties
began to drift in, and by night what might be styled windrows of them were
lying along the beach. Among them were many fish altogether strange to us;
among the known varieties were mackerel, jacks, small shark, porkfish, sheeps-
head, toadfish (several varieties), mangrove snappers, grouper, sardines, sea-
horse, cowfish, remora, moray, eels, mullet, pinfish, gurnards, ladyfish, grunts,
and many other varieties, not all of which showed the tendency to “popeye.”

Soon after this drift commenced I went to the beach accompanied by a small
dog; while on the beach I felt a slight tendency to sneeze and cough; shortly
afterwards my attention was called to the action of the dog which was sneezing
violently and seemed to be in acute distress, choking and showing every symp-
tom of asphyxiation. I carried him off the beach and in a short time he seemed
to recover, so I carried him back, and the same thing happened again. I then
noticed that my lungs were feeling sore and that my breathing was labored, in
much the same manner as when I board ships after fumigation, except that I
could notice no odor. Other people were affected the same way.

Later in the day the captain of the Cuban fishing smack Rafaela Pedre, which
had run into the harbor for water after a 45-day trip, come to the office and
told me that his entire catch of grouper and snapper had died almost imme-
diately after the tide started in. I questioned him carefully and found that
they had noticed the peculiar sensation I have above described. The next day
another smack came in with her fish dead and reported that dead fish covered
the Gulf for miles out. The captain of the Dutch steamship Zeta, which arrived
en the 8th, reported that he had passed through miles of dead fish.

In a few days the plague abated, very few more coming in.

MORTALITY OF FISHES, WEST COAST OF FLORIDA. 7

However, on the 18th another violent outbreak occurred, this being much
more serious than the first, inasmuch as it had killed many large fish which did
not seem to be the case during the first attack. For the past few days the
beach has been lined with tarpon, jewfish, grouper, and many varieties of top
fish which seemed to escape the first attack. In addition to this, many of the
bay fish are succumbing. The gas was very violent this time and many people
telephoned for medical assistance for “ cold in the head,” “sore throats,” “ cold
in the chest,” etc., besides coming to see the local physician, who is also the
United States quarantine surgeon here. I, myself, have suffered quite acutely
for the past five days, but the worst of the gas seems to be going now.

I tried the dog again, and again had to take him off. I do not think he would
have been able to live over two hours on the beach. The fish died in a very
short time. I observed a mullet dying yesterday; as the tide came into the
bayou the gas met him, he began to act strangely, coming to the top, whirling
around and around, and then sank to the bottom, lying stomach up for a little
while, when he turned on his side dead. Spadefish acted the same way. It is
now reported that the fish are dying freely in the remote bays and bayous,
every local variety seeming to give up its share. I have been told that many of
the barnacles have also died, but I can not confirm this. I have noticed that
the conchs and crabs are not dying, at least to any extent. * * *

If you desire any other information as to this matter, I shall be glad to
furnish it if it lies in my power. I meant to state that I noticed the pungent
feeling of the gas particularly when a wave “ broke” and believe that this will
explain why the top fish escaped with less visible destruction than the bottom,
the breaking of the wave aerating the water more or less. * * *

The gas has none of the characteristics of H.S; it acts with the same peculi-
arity of chlorine, but is odorless, perhaps is CO.; addition of lead acetate to
sea water gives a dense white precipitate, but am not sure but that it might do
that normally, precipitating lead chloride.

The “odorless but exceedingly irritating gas,’ as described, was
not noted by the observer, but had, perhaps, already subsided. The
protrusion of the eyeballs was due to the accumulation of gases from
decay behind ,the orbits, as only those fishes which had been dead
for some time were thus affected.

A letter from Mr. Skermer, dated November 11, 1916, reads:

I am in receipt of your letter of the Sth instant relative to the supposed
presence in the Gulf waters of Peridinii in abnormal numbers. I wish to state
that I have not been able to learn of such conditions obtaining nor have I
noticed any marine growth of abnormal appearance at any time during the
mortality periods. However, I have inquired carefully at every opportunity
since the fish began to die from any person who I had reason to suppose
had come in contact with the dying fish as to whether he had noticed any
peculiarity in the water. I learned from two persons that the fish seemed
to die in “ streaks ” and sometimes in dark-colored water ; others noticed nothing
abnormal in the appearance of the water but did speak of the odorless but
exceedingly irritating gas which seemed to be liberated at intervals. * * *

This morning I inquired of a Spanish fisherman, who lives about 7 miles
south of Boca Grande, as to conditions near him. He informed me that fish
were still dying along the Captiva Pass and inside waters of Pine Island
Sound. He further stated that the fish died when coming in contact with it.
The dark-colored water he said was in the bays and did not enter the Gulf
at all except at low water. From this I am inclined to believe that it is

8 MORTALITY OF FISHES, WEST COAST OF FLORIDA.

simply an overflow of swamp water, and do not believe that it is the cause of
the mortality.

The fish were killed many miles out in the Gulf. The captain of the Dutch
steamer Themisto, which arrived here October 27, told me that he passed
through immense numbers of dead fish 45 miles out. I asked him if he noticed
anything abnormal in the appearance of the water, and he said “No.” A
fishing smack which entered here lost all its fish after entering the bay,
and another reported that upon attempting to enter the bay saw its fish
beginning to die, and that upon turning about and going into the Gulf they
recovered. I can only reconcile the two circumstances in this way: For
several days after the fish ceased dying in the Gulf they died in the bay, and it
is probable that the last-mentioned smack met the returning current from
the bay to the Gulf, while the first-mentioned got it in full strength from the

Gulf in the beginning of the attack, as he was anchored in the tidal channel.
* * *

INVESTIGATION IN THE FIELD.

Conditions made it impossible to undertake a field investigation.
during the early stages of the mortality when it was at its worst, but
the writer arrived at Fort Myers, Fla., on the Caloosahatchee River,
November 12, and remained in the region for a period of 10 days.

Since the mortality of the fishes had been ascribed to foul water
from the Everglades, the condition of this river was first noted. No
abnormal conditions were observed in the river; small fish were
abundant; birds were feeding upon them. Schools of mullet and
red drum (“redfish”), vast numbers of ducks, and many pelicans
were seen on the river below Fort Myers. In no case was a dead
water animal found on the river. The water was of a brownish color,
due, presumably, to tannin or other pigments from the mangroves
and palmettoes, but it is understood that such a condition is not un-
favorable to fish.

On the next day a reconnoissance trip was made on a river steamer
from Fort Myers down the Caloosahatchee to Punta Rasa, thence
across San Carlos Bay to Sanibel, across the bay again to St. James
City, on Pine Island, thence across Pine Island Sound to Wulfert (in-
side mouth of Blind Pass), then through a narrow channel to Cap.
tiva, returning the same day via Sanibel and Punta Rasa. Between
Fort Myers and Punta Rasa (18 miles) the river appeared to be
normal in every respect. In San Carlos Bay dead fishes were noted,
blanched and soft, apparently having been dead for some time. On
the inside beaches of Sanibel, Pine, and Captiva Islands dead fishes
in great numbers and of a multitude of species were noted, all in a
state of decay.

On the return trip, near Sanibel Wharf, a specimen of squeteague
(Cynoscion nebulosus) was taken in a state of rigor mortis, but with-
out apparent abnormality.

U. S.B. F.—Doc. 848

PLATE I,

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MAP SHOWING REGION WHERE MORTALITY OCCURRED

U S. B. F.—Doc. 848 PLATE I]

GULF BEACH, SANIBEL ISLAND, NOVEMBER 19, 1916,

/

MORTALITY OF FISHES, WEST COAST OF FLORIDA. 9

Beginning the next day, November 13, the writer spent three days
in the vicinity of San Carlos Bay, with headquarters at Sanibel. In
this interval water samples were collected at various places in San
Carlos Bay and Pass, Pine Island Sound, Tarpon Bay, and Blind
Pass. Efforts made to collect bottom samples were successful only
in obtaining pieces of shell and fragments of a thin layer of lime
deposit which seems to cover the bottom in San Carlos Bay and Pine
Island Sound. Such qualitative tests as were made indicated a
rather strong alkalinity. On November 13 and.14 dead fishes were
in greater abundance, coming in, apparently, on the tide. On the
13th a census of dead fishes was taken covering 20 steps of the San
Carlos Beach, Sanibel Island. This census revealed 163 specimens
of fishes, of 26 species, and included neither the windrow cast up at
high tide, nor those floating, but only those at or close to the water’s
edge. On the dark nights of that week the phosphorescence of the
decaying fishes made the beach visible for a long distance, and the
sand was so charged with phosphorescent bacteria that one’s tracks
persisted for some seconds. Familiar fishes were identified by their
own light. The odor was almost intolerable; people dwelling on the
islands hauled away wagonloads and buried them in their orchards
for fertilizer. |

SPECIES AFFECTED.

In all the region covered the following species were noted :*

Species. Common name. Family.
WERE MMINGSGIIN Oe colo ccc dsccccciweeceec-= ssc Devilfish Met eaaceheeet ccicts ness cre Mantide.
Ocyarus) chrysurtis0_. 3.52... 5.32 )2s2sbees- SEGUIGNS CUE Wee © te Gre cece Goose ape eee Lutianide.
BNGOINEIIS PISOUSS 3. ca: a's o'5 ocisis ots soins sect Mangrovesnapper....-....----------- Do.
Hpinepbilus Mono: O~ ys Sl i.e 5-2-2 3282 Redieraupersrss. © best 2h fs eet Serranidee.
ORV NI) < gOS Paes te aee INASSATE PLOUP CRY eis aneeswece cosas ccs Do.
Garmupamipritia ly is... det soc. bs ane sclens UG yaa SUR e oes Oo eee i ee Do.
Centropristes striatus.-..............-..--..-- PSLEEEM] Op 9S55) 8 0a pepe Do.
Montleimbusispl 52 s2.<). 7.205. 225-422-0254255 Nahi baters Oy8 21 a Be op eS ees Scienide.
CYHOSCION HEDUIOSUS= -.s.c.eic cc. soc ss' dace Spotted squeteague (“‘trout”)........ Do.
S22 S768 08 sHos soeeaaaaeonc cis -ee ee oaer bse Squeteague (“‘trout”’).........--.-.-- Do.
ESUECIO MEDS seme semce os Joc -neceee cuca Sena EHO NOR GU meee eeleeiee sieleere lai2 eral at Do.
WPOPODIAS CROWNS Ts oo be os oa ./d2 22 - ce ashes Bleck drumi(Sdrum??). 3... 2222. .<-n- Do.
Sciznops ocellatus...................- % Posen Red drum, channel bass (‘‘redfish’’) - . Do.
Tarpon atlanticuso................-..-+-2.--- MLN Ogi ti 5 2 5e8 $5552 SBP Ree eoepseee ec Elopidz.
CALaRAH ID DOSF a a. oo wai oe cael sco ce ae aerate @ROVAII GE eee hence een see sca Carangide.
Carank ChyS0Ssccc< 2250-3 san ee sete pe abses. Crevalle ¢'skip jack??) is. .--5----2see4 Do.
Selone-vomen sy: ses hoa csesee can coke accns IMIGOMUADN oat nis Succie deo c<cis ce aucsipais Do.
Trachinotus carolinus.....................+--- Tease Bee ee eeas ane EEO a cre ener Do.
Ohroplites saAULUs. cose sees soe wee otisk ee Sete MERLUErIACKOLEce ta ans winic'e'a ns cteinrese eats Do.
SIMD TREES S70 on Set bedagoseac ser ee ore Pep sonee Scorpius soe ces- os teste n sees ee Scorpenide.
LUin SNES oes 6 oe aoe So Beue crebocaeseEes | MIG 32322 So Soct Sadstbeedceanohoseosc 3 Mugilide.
Hemulon plumieri....... eRe ee een es eee Grebe eee ene oe ache See tae cee nee Hemulide.
TE) S(CUGIRIE =. o Dee men OSD SHOBEEOAr cee Ree cease eee (00) SG aos RRoeope doce SERCO EEA ce Do.
Bathystoma rimator..............--.--22----- RG OUth SrUND. oc) cto- nian= mainte eleine Do.
PATUINOLFEMUSCVIFSIMICUS . o ac cock casaceccccee sae PORKASH 4 2655 seperate A yuh Merete alge Do.
MOBARCHAUNUSSD os. seo aee eee dae ee sew se ak oie WIS HSN. Ss Wa cesws docs osama oneseas Monacanthide.
Wareeee ese. a2 oe Sea S Race: bos Soscose seed ese GO oe dace sts Bhs Se abst Soe 0.
Scomberomorus regalis..........-.-...-...---- Ceros inigfish 6 ccs pote kiosk ea agee Seombride.
DINNOO IRE PIN AUD es se sob. ceneececcscee ees QUSEIGE SE rr ee eee ccine Ophidiide.
SCHLUSMVeNINEe wes socn sen SAO Nl ke eee uk wale Parrothish cect ye- weet ee res Scaride.

a The identifications here represented are, of course, open to question. Time did not admit of careful
study. On the great majority of the fishes the colors had faded, of several species only badly decomposed
specimens were seen, and some of the others were quite unfamiliar to the observer.

b Not seen by writer, but reported by fishermen and others.

87829—17——2 BOG Ue tee anaes. |

10

Species. Common name.
Chietodiptertus faber.< 522222222. ooo se nice Shadene Se aie Aca Be ARs Le ee A ic
Archosargus probatocephalus..........------- Sheepsherds saeese sees eee eee eee
Otrynter.capnnuss! 2226 322 eeacg 2 ens ee Long-spine porey. )s sss secs ese does ee
Calamusispi.-2 2 sche sa nceccneeerece sens cee POLE is ose pce saseeee eee ee
Lycodontis Gnoringa?) Sst ceee aie ae te se Black Moray o-asescc te ce so does eeeteee
L. Gordanit) ee ose eee sen aaa meee Spoiled Moraycre.- cases see ese ete.
Peralichthys'epiites sss sseeee ee eee ee eres Lig lop thete f=) eager es fl Cm ee Fe od ee
HicheneisTremorgss.-. ssc ceca wwecee se ae oe west Remora, shark pilot..........-----..-
Clupanodon pseudohispanicus..............-- Sardinei(‘shiner?) =i eeeeaseeneee ese
Brevoortia tyrannus os. 2p sees.) eeree seeerenene Menhaden ont ees: J. tape oe seeee saan
Cheetodon ocellatus << seis): eae eee utteeeaae SF cee chr ee ae
Angelichthys cilignis: Soo sen ec cese ence mee ‘Angelfish s soos 2 oleae See
Lactophrystricomiss.2 cs oe. cecdeeee dee one Trunidish (Scowfish?,)j-s.2 cc. gee cee
Lactophbrys trigonus- << 25-2. ---.-os-- sree Trunkcfigh J (2 ee eee eras eee eel
Prionobus spe-s2 eit ase sGaaetemee ce see eacoete Sea robin BASS 53 HEROS ee i so eee
ODSaNUS SP 22245 jose oon nee ce neceeee sbes secon Poadtisn. se eee. nese ee ee ee
Spheroides septs: 2522 Seeker eee Puffer (stoadfish?)/25--.-f2sns. aiooae
Chilomycterus spinosus.............-----.---- Burrs. i5) o)-ceacecee oer eoeeeeten
Dasyatisi (SAYi2) cee soos coke a eke eee eee tenes Biting TAY. oi gekacebacbeee cn eee ee:
RAjaS) nytt ee ean ae eee rae eee eee DEAGO. 282 ood ces cess cae epee ets
Zito pats MnaArMArieia. sce ce ecce ceo eene bene Spotted sting ray 2.2. 566.2022. 2232
Rhinobatus lentiginosus............---.------ Uitar HS ce ee sate sca s eaeee sass
Weliehthys feliss22. 33.05.05. 4222-5 ee Gaff-topsail catfish... .
Galeichthys (milberti?). - 22.2 oa. 22h ccee ee oeee Sea catfish... 022... ...
Hemirhamphus)sp ee ses be eee ee ace eee Halfbeak; needlefish................-.-
TYIQSULUS/SP 2/5 eee eco es ee cl eee eee Marine gar; needlefish .
os sels paleiechiosiniemc cess otis Senlcee ee pee eee Small eel; whip eel...
Leptocephalus conger .-| Conger entice out
Synodusificetens soot ae cetscties cecteeeien -| Quizard fishiosese
Sphyrnntiburases et eet eee .-| Shovel-nose shar
Carcharimus)(ODSCuUruIs?)/2 o.oo pec oeeeeeenene Sark in dsc wince aac comees coer eeeeesaeee
Albula wulpess (5. 223.2% fo ce aa epee Lady fishin osc os tec cte Gee ee eee
Ogcocephalus vespertilio................-...-- | Dathsh aes eases woecoae sees

MORTALITY OF FISHES, WEST COAST OF FLORIDA.

Pleuronectide.
Echeneidide.
Clu oie

Chertodontide.
as ae
Triglidie, ;
Batrachoididee.

Tetraodontide.
Diodontide.

baat

gti:
phide.

pat Hie loninied
eat | Moringuidee?
.| Leptocephalide.

Synodontide.

f Sphyrnide.

Galeide.
Albulide. |
Ogcocephalide.

Of invertebrates, sea urchins (Arbacia), the king, or horseshoe
crab (Limulus), and sponges were noted. It is a matter worth noting
that very few animals other than fishes were killed. Barnacles,
oysters, and mussels were examined, but they were in good condition.
Live conchs and hermit crabs were repeatedly observed. Porpoises
were plentiful during the period of observation. Pelicans and other
Buzzards were common in the lo-
cality, yet they neglected the dead fish entirely.

The dead fauna of the Gulf beach was not markedly different from

water birds behaved normally.

that of the bays.

Relatively more carangids, sharks, and rays were

seen, but many of the dead forms were buried in the hard beach sand,
hence the Gulf beach did not present such a striking picture as did

the inside beaches.

Taking the whole territory into consideration the

relative abundance of the different species is estimated as follows in
the order given, less abundant species being omitted :
Grunt (Hemulon plumieri) (H. sciurus).

Mullet (Mugil cephalus).

Trunkfish (Lactophrys trigonus) (L. tricornis).

Puffer (Spheroides sp.).

Menhaden (Brevoortia tyrannus).
Sardine (Clupanodon pseudohispanicus).
Red-mouth grunt (Bathystoma rimator).

Spadefish (Chetodipterus faber).
Moray (Lycodontis sp.).
Filefish (Monacanthus ?).

Sheepshead (Archosargus probatocephalus).
Spotted squeteague (Cynoscion nebulosus).

MORTALITY OF FISHES, WEST COAST OF FLORIDA. 11

It is assumed that the numbers are representative of the relative
abundance of these forms in life. The sizes of specimens would also
suggest that all true fishes were killed, regardless of size. They
range from jewfish of approximately 200 pounds to forms less than
2 inches long.

METEOROLOGICAL CONDITIONS.

The temperature of the water was around 75° F. until November 15.
On this date a violent “northwester” blew up, occasioning a series
of extraordinarily high and low tides. After this the temperature
was 65° F., and continued at about that figure through the remainder
of the observation period. Contrary to what might be expected, the
mortality of fishes did not cease after the storm. In this connection
it may be added that the wind had been blowing constantly from the
northeast for several weeks previously and, after the storm, shifted
around to the northeast again.

The water was olivaceous in color—about such a color as would be
expected from a mixture of séa water with the brownish water of
the rivers. Those accustomed to seeing the water stated that during
the period of mortality the water was of a more brownish color than
usual. The wake of the boats had an oily appearance, or was appar-
ently not so effervescent as that in normal sea water. It was further
stated that at the height of the mortality, on the Gulf coast, the water
was of an amber color (by transmitted light). This colored water
was described as being not uniformly distributed, but occurring in
streaks, and it was in these streaks that the fish are said to have
perished. A resident of the island described the death of a mullet
thus:

The fisherman was following a large mullet in Tarpon Bay (partly inclosed
in Sanibel Island), intending to capture it with a cast net. The fish, at a depth
of possibly 2 feet, seemed suddenly to strike a streak of the bad water, came
rapidly to the surface, flipped from the water, and, after a short struggle, ex-
pired.

The exact spot, about 6 feet from shore, was visited by the observer,
but nothing unusual was noted. Several dead mullets were seen
ashore; live porpoises and conchs were in the water.

EXAMINATION OF SPECIMENS.

- On November 16 a mangrove snapper (Neomenis griseus) was
taken by a boatman in a moribund condition. The writer first saw
this fish a few minutes after it had died, and he at once dissected it.
The blood was not yet coagulated, and, indeed, seemed less inclined
to coagulate than one might expect. The fish was not infested with
parasites, no lesions were noted, the gills were pink (perhaps too
red), the stomach contents were small fish, clean and constituting an

12 MORTALITY OF FISHES, WEST COAST OF FLORIDA.

apparently wholesome food. The liver was slightly abnormal in
appearance, being faintly mottled with a lighter shade of brown.
The mucous covering of the body was transparent and colorless;
none of the organs were distended by gas, nor were gas bubbles
observed in the blood vessels. The eyes were clear, and no evidence
of fungus was seen. The coloring of the fish was vigorous.

Fishes in a moribund condition were reported as having been ob-
served in the passes, in the Gulf, and in Tarpon Bay, but since the
carcasses drifted with wind and tide the mere presence of dead fish
was not an indication of a mortality at any given place. The condi-
tion sought for must have been immediately at hand, however, when
a moribund fish was observed on November 19.

It was a small filefish (Jfonacanthus sp.), and was first observed
near the dock at Bailey’s Wharf, Sanibel, in water not over 3 feet
deep. The fish was brilliantly mottled with maroon on a slate-
colored background. It was drifting upon its side, making but
slight effort to balance. This fish was captured and placed in a
bucket of the water from which the fish was taken. A moment later
a small, active, pinfish was captured in the same place and likewise
kept in another bucket with some of the same water. The color of
the filefish faded, but repeatedly revived when the fish was disturbed ;
each response, however, was weaker than the preceding one until the
fish died, and the color faded in about 2 hours. The pinfish, taken at
the same time and place, lived till it was released at Fort Myers,
about 6 hours later. Both species had repeatedly been noted dead
upon the beach. Within 50 feet of the point where the filefish was
dying numerous mangrove-snappers and sheepshead were seen, quite
healthy in appearance. So we have the anomalous condition of
dying fish and perfectly healthy fish within 50 feet of each other
and in the same water, with certain knowledge that all the species
concerned are subject to destruction by the abnormality Phys
for the death of so many species.

Representations were made to the writer concerning the pollution
of Peace River. This is a small sluggish stream, tributary to Char-
lotte Harbor, and drains a region now being worked for phosphate
rock. It was said that the waste from the works destroyed the fish.
However true this may be, a brief visit only was necessary to show
that such a pollution could have no bearing on the mortality under
consideration. Small fish as well as vegetation were in the stream;
and, besides, the stream is of insignificant size.

DISCUSSION OF POSSIBLE CAUSES OF THIS AND SIMILAR DIS;
ASTERS IN OTHER wien OF THE WORLD.

It may said at the beginning of this discussion that while a definite
conclusion has not been reached as to the cause or causes of this

U.S. B. F.—Doc. 848 PLATE III.

VIEWS OF SAN CARLOS BEACH, SANIBEL ISLAND, NOVEMBER 19, 1916.

U.S. B. F.—Doc 848. PLATE IV:

VIEWS OF SAN CARLOS BEACH, SANIBEL ISLAND, NOVEMBER 19, 1916.

MORTALITY OF FISHES, WEST COAST OF FLORIDA. 13

mortality, yet certain possible causes are shown not to be operative.
Furthermore, significant circumstances in the case of 1916 and of
previous years, records of similar disasters in other parts of the
world, and opinions of representatives of the numerous sciences con-
cerned, are brought together here as the basis of discussion and also
for further work, if there should be a recurrence of the phenomenon.

The mortality occurred in 1844, 1854 (Ingersoll, 1882), and a very
severe attack was reported in January, 1878. In August, September,
October, and November, 1880, it occurred again, but in relatively
milder form. The last two instances are said to have been preceded
by earthquakes. In July, 1882, the plague returned; in this case it
may be connected with the tilefish disaster, which occurred at the
edge of the continental shelf south of Nantucket along the 100-
fathom line. In the summer of 1908 a similar mortality destroyed
the sponge beds along the keys between Key West and the mainland.
In 1916, as above stated, the mortality was exceedingly severe be-
tween Boca Grande Pass and Big Marco Pass. The older reports are
meager and not based on direct observations; in some cases inverte-
brates—chiefly sponges and king crabs—were predominant, in others,
sharks and porpoises. It may, then, be assumed that the reports
furnish no reliable indication of exact conditions.

The causes suggested are (1) water from the Everglades charged
with tannin and products of decomposition of palmettoes and man-
groves; (2) extraordinary abundance of Peridiniwm known to have
occasioned the death of fishes in different parts of the world; (3) a
disease, fungoid, parasitic, or bacterial; (4) dilution of the water by
unusually heavy rains; (5) an issue of gas, volcanic or natural; and
(6) earthquakes or seaquakes.

FOUL WATER FROM THE EVERGLADES.

1. A hypothesis that has been advanced repeatedly is that water
from the Everglades, charged with tannin and the products of decay
in vegetation, is brought down by the rivers and kills fishes. It may
be said with sufficient certainty that this is an impossible explana-
tion. For there are no a priori grounds for assuming that the Ever-
glade water is poisonous; nor is there any material evidence of such
a condition.. No fresh-water fishes were killed; life in the river was
normal; and fishes are known to live in the Everglades. The sporadic
appearance of the phenomenon casts doubt on the possibility of such
an explanation. And, finally, it seems quite impossible to believe
that the volumes of the rivers are sufficient to account for such a
widespread distribution of the mortality. It may be, however, that |
the accumulation of the river load as a decaying organic sediment

14 MORTALITY OF FISHES, WEST COAST OF FLORIDA.

furnishes the gases and other products of decomposition confined
for a time, but sporadically released by what may be found to be the
proximate cause—seismic disturbances. This possibility will be
discussed later.

PERIDINIUM AND OTHER PROTISTS.

2. An extraordinary abundance of Peridinium has, at times, caused
the death of a great number of fish and crustacea. Under certain
circumstances, as yet unknown, these organisms multiply in vast
numbers, giving the sea a reddish or chocolate color. Such colored
areas are usually accompanied by an offensive smell, and are sharply
marked off from the unaffected water. They have been encountered
by mariners in many parts of the world, and numerous accounts ap-
pear in the literature. Darwin (1846) observed it “a degree south
of Valparaiso,” Nishikawa (1901) and Mitsukuri (1904) on the
Japan coast, Carter (1858) around the island of Bombay, Mead
(1898) in Narragansett Bay, Smith (1903) in Manila Bay. Both
Darwin and Carter cite numerous other references.

Dr. R. E. Coker records (in unpublished notes) from the coast of
Peru a phenomenon possibly due to the same cause and commonly
known as the “painter.” ‘This. phenomenon has been described by
Hutchinson (1873) thus:

* * * There is an interesting peculiarity here * * * ealled the
* painter,” the palpable evidences of which consist in a changed color of the .
sea water (most generally to a muddy white), an odor most foetid, nauseous,
and depressing, with the accompaniment of the white paint on ships and boats,
inside as well as outside, becoming totally discolored and often partially
black. * * * Jam induced to attribute this emanation chiefly to submarine
voleanie action, generating sulphuretted hydrogen gas. * * * Although met
with at Callao, in its most aggravated form, the “painter” is likewise found
along the coast as far as San Jose de Lambayeque, nearly 500 miles north.
From the end of December until April is the time when the phenomenon
mostly exists.

I have before me an analysis of the sea water of Callao, bottled up during
the existence of the “painter” and having some mud from the bottom of the
bay contained therein. This was sent * * * to London, and was there
analyzed by Mr. T. Keates. Mr. Keates reports that, after being allowed to
rest, the water poured off proved to be sea water and that the black mud left,
after the water had been decanted, was in a state of active decomposition,
large quantities of sulphuretted hyrogen gas as well as sulphate [sic] of ammo-
nia being given off. The black color of the mud was found to be owing to the
presence of sulphate [sic] of iron which was formed as a result of the decom-
position mentioned. Whilst this latter was due to the sulphur of the organic
matter combining with the iron present in the mineral part of the mud, to
produce the black sulphide [sic] * * *.

1,000 parts of the mud dried at 230° F. yields:
Water .n2sse us seep ce eee Ee eee ee Be ee eee ore 769. 6

Di th i eS Oe eee

=—

— =-_— SS ae”

MORTALITY OF FISHES, WEST COAST OF FLORIDA. 15

100 parts of the mud dried yielding by analysis:

(OE SaeE TAN een EAT ea a et i aR Pa OUR 10. 50
Chloride of sodium, alkaline sulphates, ete____________________ 6. 43
Salis OL iine ae ee sare CLS te A ate ee et eb 3. 75
Alumina? of [and ?]\ oxide'of iron [sie]iv oles ee 16. 00
Siligeous/ mater ies! ola tddienn fot dy te det oe bet ois 63. 25
DESY SSU SY ye AIRES Gr ADE AS ORN tee AS ne GREATS 9 NON ON ara URES AGL Mae: ea GO Soe OY a . OT

* <* * In the course of a few days I observed the water of the bay under
four different aspects.

First. Ochre-brown, with somewhat of a reddish tinge, and opaque. This,
when examined under the microscope, showed animalcule of a spheroid or
circular form and .of like color to the water. In 12 hours after it was—

Second. Of a dark green, and still thick aspect, in which, by the microscope,
was visible another class of animalcule of an hourglass form, round and broad
at each end, but contracted at the center. Although there was but one drop
of the water under the glass, a large number of these jumped about.

Third. The next morning, or in 14 to 16 hours afterwards, the water was a
muddyish white. This time the smell in the harbor was most pungently nause-

‘ating. It is considered the true “ painter ” when white paint becomes black,

and headaches are general, with everybody under its influence. No animalculse
were visible through the microscope in this state of affairs from the second to
the third condition. I may add that in the intervening period we had a shock
of earthquake at about 5 o’clock in the morning, and during the occurrence of
which it may be conjectured submarine volcanic action destroyed all animal life
of these insects seen two days previously.

Fourth. This is the ordinary water of Callao Bay. * * *

From Hutchinson’s description it would appear doubtful that this
was Peridinitum. Darwin’s observations (1846) may help to clear
this up:

On the coast of Chile, a few leagues north of Concepcion, the Beagle one day
passed through great bands of muddy water exactly like that of a swollen
river; and again, a degree south of Valparaiso, when 50 miles from land, the
same appearance was still more extensive. Some of the water placed in a glass
was of a pale reddish tint and, examined under a microscope, was seen to
swarm with minute animalcule darting about and often exploding. Their shape
is oval and contracted in the middle by a ring of vibrating curved ciliz. It was,
however, very difficult to examine them with care, for almost the instant motion
ceased, even while crossing the field of vision, their bodies burst. Sometimes
both ends would burst at once, sometimes only one, and a quantity of coarse,
brownish granular matter was ejected. The animal an instant before bursting
expanded to half again its natural size, and the explosion took place about 15
seconds after the rapid progressive motion had ‘ceased; in a few cases it was
preceded for a short interval by a rotatory movement on the longer axis. About
two minutes after any number were isolated in a drop of water they thus
perished.

This may explain the ephemeral nature of the animalcule, and
also, since they die in such vast numbers, it is not difficult to con-
ceive the consequences of the decay of so much organic matter.

Carter (1858) shows that the various hues of sea water, as described,
are due, at least around the Island of Bombay, to one organism, Peri-
dinium sanguineum. In the swimming stage the organism is green

16 MORTALITY OF FISHES, WEST COAST OF FLORIDA.

and translucent; as the transition time approaches, the chlorophyll-
like substance responsible for the green color disappears, a red sub-
stance takes its place and dissolves in oil globules that have been
forming. At this stage it is red and visible to the naked eye. After
only a few days the individuals assemble, lose their red color,
become encapsulated (Protococcus form), and sink or float on the
surface. This stage is followed by a subdivision into two or four
new ones. This latter process may be repeated several times until
eventually a ciliated form appears again, completing the life cycle.
The latter form is covered by an excessively fragile shell which “is
broken by the pressure of the thinnest piece of glass.”

This description explains the varying color of the streaks, the
periodicity, and it may explain the bursting observed by Darwin,
if he used cover glasses in observing them.

Could this have been the cause of the trouble in Florida? No
evidence of the presence, in extraordinary numbers, of these organ-—
isms was found. When the water was described as red, further
questioning brought out the fact that it was by transmitted light
on the beach, and not by reflected hght. Fishes observed while dying
were in clear water. Still, the condition as described may have
existed before the writer arrived, and the dissolved decomposition
gases might have persisted in the water to an extent fatal to fishes
after the organisms responsible had perished. Or the organisms
might have become lost from view either by disintegration or by
passing into the protococcus form and sinking, as suggested by
Carter (1858). But such red water, to explain the conditions found,
would have to be distributed over an unprecedentedly large area to
persist for two months and yet escape detection by the many passing
ships, and it would be necessary to explain the widely fluctuating
periodicity, in some cases one year, in two other cases 24 and 25
years, respectively.

Gilchrist (1914) definitely ascribes certain,instances of mortality
on the South African coast to Noctiluca and to diatoms. These
forms, decaying in large numbers in the water, make the latter an
unfit medium for fishes. Among the instances described by him as
due to obscure causes, one is clearly due to Peridinium.

DISEASE AND PARASITES.

3. Evidence of disease or parasitism is likewise lacking, as is shown
by the examination and dissection of specimens already described.
On the other hand, it would be difficult to believe, without the most
thoroughly convincing evidence, that so many species of animals
could be affected by an epidemic of any single disease, or that such

a

a ai lls

MORTALITY OF FISHES, WEST COAST OF FLORIDA. ‘* 17

a disease would confine itself to a limited locality for the larger
part of a century or perhaps a much longer period of unrecorded

observation.

DILUTION OF THE WATER.

4. Dilution of the water hardly deserves serious consideration, for
the phenomenon is not correlated with the rainy season or unusual
discharge of the rivers. As shown by the table, the salinity does not
indicate serious dilution of the water. Of course a dilution ade-
quate to explain the mortality of fishes would concern only an excess
of run-off above the normal. The area of ocean concerned, in com-
parison with the small rivers, at once negatives this hypothesis; and
if the water were sufficiently diluted, it may be assumed with good
reason that unconfined fishes would seek their proper salinity by
migration. |

VOLCANIC AND NATURAL GASES.

5. It is now time to call particular attention to certain circumstances
of prime importance that have served largely to destroy the fore-
going suggested causes, and which can not be overlooked in arriving
at a conclusion. They are (a) the irregular periodicity, both as to
years and seasons; (0) the strictly marine aspect of the phenomenon;
(c) the large area covered; (d) the definite limitation of this local-
ity; (e) the limitation of the mortality to the animals, whose res-
piration is performed by an oxygen carrier, hemoglobin, hemocyanin,
etc.; (7) the progressive southward appearance of the mortality.

The irregular periodicity, the marine aspect, the area covered, and
particularly the limitation to the region concerned all suggest a geo-
logical explanation, whether the issue of a gas or the occurrence of
an earthquake, fixed in one place, sporadic in outbreak, and inde-
pendent of weather fluctuations. The species affected and the south-
ward progress are not contradictory to such an explanation, as will
be seen.

Dr. T. W. Vaughan, of the United States Geological Survey, stated
verbally to the writer that he saw only the remotest possibility of
a voleanic gas in this region. The region is inactive volcanically,
and the discovery of a volcanic fumarole would occasion great sur-
prize to geologists. Beyond that we have nothing for or against
voleanoes.’ There is no question that volcanic gases would be deadly
to fishes. For, while volcanoes emit different gases in different stages
of their activity, the emissions always contain substances deadly to
fishes, if nothing worse than carbon dioxide It is scarcely necessary
to present data here as to the composition of such gases. Any chlo-

18 MORTALITY OF FISHES, WEST COAST OF FLORIDA.

rine, as hydrochloric acid or as ammonium chloride, or in any
soluble combination whatever, would certainly be detected by the
chlorine determination (salinity) ; sulphur gases and carbon dioxide
would alter the alkalinity of the water, though much would depend
on the freshness of the water when the determinations were made.
An unfortunate delay impaired the value of the samples collected;
it was therefore impossible to determine whether or not these gases
were present.

Similar remarks concerning natural gas issues may be made. Such
gases consist, of course, largely of the light paraffins, usually small
quantities of olefines and occasionally some carbon monoxide. Little
is known of the effects of these gases on fish. The injury to man
done by methane is done chiefly or entirely by the mere dilution of
the air by this gas. Ethylene and ethane probably act in a similar
manner. These gases are slightly soluble in water, ethylene to the
extent of 4 per cent volume. In water these gases could not act as
they do in air, for the solubility of a gas is quite independent of all
other gases and as much oxygen would be present in a saturated so-
lution of any of them as in their total absence. .

Of carbon monoxide more can be said. This gas acts as a poison
to animals, whose respiration is dependent on a blood pigment by
combining firmly with the pigment to the exclusion of oxygen; while
these animals situated in the presence of abundant oxygen and pre-
senting a wide area of “ semipermeable ” skin, and whose respiration
is performed by the agency of oxygen dissolved in the blood plasma,
are immune, since carbon monoxide does not interfere with the pas-
sage of oxygen into the body (Leitch, 1916). Carbon monoxide is
soluble to a sufficient extent thus to interfere with respiration. It is
therefore suggestive to note that all the animals killed, except sponges,
were dependent on a blood pigment (hzmoglobin, hemocyanin, echi-
nochrom, etc.). Sponges are the only animals observed on the
beaches whose respiration is not dependent on one of these carriers
or pigments, but sponges are often seen, even in normal times on the
beaches.

In February and March, 1894, the Albatross investigated and re-
ported on a case of widespread mortality of fishes off the coast of
California between Santa Barbara and San Diego. Evidences there
obtained indicated petroleum and hydrocarbon gases as the cause of
the disaster. Many species were killed, but those dead were chiefly
flatfish and barracuda. The odor of petroleum was evident from the
dead fish. The body slime was colored yellow in patches, and the gall
bladder was ruptured. The oil springs said to exist off the coast were
held responsible for the oil and gas issues.

MORTALITY OF FISHES, WEST COAST OF FLORIDA. 19
EARTHQUAKES.

6. Earthquakes kill fishes directly by concussion. Oldham (1899)
cites the case of the destruction of fishes in the Sumesari River in
India by the great earthquake of June 12, 1897, which killed “ myri-
ads as by the explosion of a dynamite cartridge.” Numerous other
instances are cited by various authors.

It is not evident in this case from the data at hand that earth-
quakes killed the fishes directly by concussion. The following extract
from a letter from the United States Weather Bureau bears on this
point:

Our records show that during 1916 there were no seismic disturbances of
any considerable severity in the Gulf region.

We have no precise earthquake records of that region for the earlier dates,
1844 * * * 1908, but probably no severe ones occurred, as this is not an
active seismic region.

Further than this, the long duration of the mortality, the south-
ward progress, and particularly the death of fishes under observation
in the partly inclosed shallow water, entirely dismisses the hypothesis
of direct injury by shock.

It seems possible, however, that the incidental effects of earth-
quakes might explain the death of the fishes. For instance, gases
are sometimes emitted along with the shock. The following quota-
tion from Darwin pertains to this aspect of the subject:

In Capt. Fitz Roy’s excellent account of the earthquake (Chile, 1833, Jan.
20), it is said that two explosions, one like a column of smoke and another like
the blowing of a great whale, were seen in the bay. The water also appeared
everywhere to be boiling; and it became black and exhaled a most disagreeable
sulphurous smell. These latter circumstances were observed in the Bay of
Valparaiso during the earthquake of 1822; they may, I think, be accounted
for by the disturbance of the mud at the bottom of the sea containing organic
matter in decay. In the Bay of Callao during a calm day I noticed that as
the ship dragged her cable over the bottom its course was marked by a line of
bubbles.

Prof. J. B. Woodworth, of the Harvard seismographic station, sets
forth, in a letter of some length, a possibility which has not been con-
sidered, and which seems worth investigating. The substance of his
letter is as follows:

Previous to the cases of 1908 and 1916 there are no satisfactory
records of seismic activity in the region concerned. It may be quite
possible, however, that unobserved shocks of low intensity could ex-
plain the mortality ; that occluded gases, resulting from the decay of
sedimentary organic matter, are released by a disturbance of the sedi-
ment, under which circumstances the occluded gases would rise into
the water, dissolve, and interfere with the life processes of fishes.
Or, at the edge of the rather wide continental shelf in this region, a

20 MORTALITY OF FISHES, WEST COAST OF FLORIDA.

seismic disturbance of low intensity might cause accumulated sedi-
ments to slide off into abyssal water, similarly releasing occluded
gases and also mixing up-the mud with the water. It is known that
microseisms (as Prof. Woodworth terms them) are radiated from
this locality, and it is believed by some that they are due to the West
Indian cyclonic storms.

This seems to be the most promising hypothesis. It might be ex-
pected that the water flowing into this region carries a large amount
of organic matter leached from the abundant Florida vegetation and
held in colloidal solution; that this organic matter, on striking sea
water heavily charged with lime is flocculated and falls to the bottom
on the uncommonly wide expanse of continental shelf in this region;
that as it accumulates on the bottom it decays anaerobically, yielding
methane, hydrogen sulphide, possibly carbon monoxide, and other
gases; that these gases, as generated, are confined by the pressure, in-
creasing sediment, and, perhaps by the limestone crust which appears
to cover the bottom; that an earthquake shock, even an unnoticeably
mild one, would so disturb the sediment, or break the crust, as to
release the occluded gases, and that these gases work, by various
physiological and chemical means, the injury to fishes. These organic
gases, being rare in sea water, would never be detected by the ordi-
nary analyses.

The work of Prof. J. P. McClendon at Tortugas, in the summer of
1916, suggests that the marginal supply of oxygen in this region is
not great. In a letter on the subject he says:

I think probably lack of oxygen killed the fish. When the Py of tropical sea
water reaches about 7.5 there is no oxygen left in the water. At Tortugas the
Ps was about 8.15 and there was about 4 ec. of oxygen per liter.

It would, of course, be necessary to explain any deficiency of
oxygen.

ALKALINITY AND SALINITY OF THE WATER.

These two determinations were made as being most likely to reveal
any unusual condition of the water. The alkalinity is somewhat
higher than that of pure sea water. Dole found this to vary between
0.00237 N and 0.00257 N; McClendon found the alkalinity at Tor-
tugas in 1916 to lie between 0.0023 N and 0.0025 N, while the samples
taken in the region under discussion had an alkalinity varying from
0.00286 N to 0.00297 N. This may be explained by the large amount
of fresh water flowing into the salt water in this region, which is
generally rather strongly alkaline. The salinity is lower than that
of pure sea water; this is likewise explained by the fresh water
flowing in.

ae ee
ee

MORTALITY OF FISHES, WEST COAST OF FLORIDA. OL

_ It is noteworthy that the water in which the filefish was seen to die
was of the highest salinity and lowest alkalinity found. Otherwise,
there seem to be no factors showing any striking correlation.

The following are the results of such determinations as were made:

ALKALINITY AND SALINITY.

Fraction
Date. of normal) Salinity. k Remarks.
alkali.
1916
9/00

Nov. 19....- 0. 00297 29.94 | In shallow water at Bailey’s wharf, Sanibel, where filefish died.

Nov. 18..-.-. . 00294 32. 81 ee ponies wharf; surface; day before storm; sealed in glass;

Nov. 16..... . 00289 31.52 | Sanibel post-office wharf; surface; day after storm; 65° F.; very low tide.

Novy. 19....| .00288 30.61 | Bailey’s wharf, Sanibel; 2 fathoms (bottom); 50 feet from pomt where
filefish died; live mangrove Sere:

Nov. 14..... . 00282 33.93 | One-half mile from Point Ybel Light, San Carlos Pass; 75° F.

DOS. 22: . 00277 34.20 | One and one-half miles from Point Ybel Light, San Carlos Pass; sample
from surface; water 2 fathoms; 72.4° F.

Nov. 15....- . 00277 32.96 | Place where mullet died, shallow water of Tarpon Bay; described by
Benpirpans 13 hours before storm; 75.3° F.; live conchs; porpoises in
water.

Prior to . 00272 33.10 | Specimens submitted by West Coast Fish Co., Kitchins Island, Pine

Novy. 13. Island Sound.

Nov. 19....- . 00261 30.97 | Bottom (2 fathoms) off Point Ybel Light wharf, Sanibel, 14 miles from
point where filefish died; 65.4° F.

Nov. 15....} .00260 32.43 | Near Gulf mouth, Blind Pass; rising tide; surface sample; 24 fathoms
wee 20 minutes before storm broke; 75.8° F.; probably pure Gulf
water.

Nov.19....| .00236 31.98 | Surf water on Gulf Beach.

Mean..... . 00276 31. 56

OTHER MORTALITIES DUE TO OBSCURE CAUSES.

Other mortalities have occurred in different parts of the world, due
to obscure causes. Austin H. Clark (1903) observed a mortality of
fishes on the coast of Venezuela, which seems similar to that off the
Florida coast. Nordenskiéld (1882) noted dead Gadus polaris in the
Siberian Polar Sea, which he supposes to have been killed by an in-

‘sufficiency of oxygen, under the ice, where the fish were confined.

Cold has unquestionably brought about the death of fishes in many
parts of the world.¢

Gilchrist (1914) cites numerous mortalities on the South African
coast in addition to those already cited, ascribed to Peridiniwm,
Noctiluca, and diatoms, but altogether without satisfactory explana-
tion. One, however, deserves particular mention. In this case (which
repeats itself annually at Knysna) there was a narrow streak of
yellowish water extending along the coast for miles, of a temperature
about 10° F. lower than the blue ocean water farther out, which was
clearly marked off from the yellowish water. The author attempts to
explain this by the meeting off this coast of the Mozambique (warm)

aQOn Feb. 2 and 3, 1917, a “freeze”? occurred on both coasts of Florida, killing thou-
sands of fishes. This cold wave is described by R. H. Fitch in a forthcoming paper of the

Weather Bureau.

4 MORTALITY OF FISHES, WEST COAST OF FLORIDA.

and the Antarctic (cold) currents by which the cold water is forced
upward along the coast and is limited offshore by the warm current.
The periodic nature of the phenomenon is, however, not explained.

This mortality of fishes on the Florida coast may be of interest and
importance in many respects. It would hardly be an exaggeration to
assert that the number of fishes that perished would be sufficient
to supply the State of Florida for a season Yet a few weeks after
normal conditions were restored we were informed that fishing on
the Florida coast was as good as ever.*. These facts give rise to the
suggestion that, enormous as are the numbers of fishes in our coastal
waters, natural causes may be quite as destructive to them as are the
activities of man.

The question has arisen repeatedly as to the means by which the
strata, rich in fossils of fishes, were laid down. Instances like this
and dozens of other in as many parts of the world readily answer the
question. Large numbers of decaying animals may also have a bear-
ing on the formation of other mineral beds—the phosphates, for
example, that might be produced from the organic phosphorus.

Tt is also true that, if this misfortune should occur again, valuable
information may be gained concerning the presence and number of
the various species of fishes, their winter habitat, distribution of sizes,
etc., from a study of the dead fishes themselves.

SUMMARY AND CONCLUSIONS.

A mortality of fishes occurred on the coast of Florida from October
3 to the last of November, 1916, appearing progressively southward
from Boca Grande to Marco, and apparently killing representatives
of all local species of fishes, but very few other aquatic animals, in
the sounds inclosed by the keys and in the Gulf of Mexico for a dis-
tance of 45 miles or more, but not affecting fresh-water forms.
Meteorological conditions were normal. Post-mortems revealed noth-
ing pathological in the fishes. The salinity of the water was some-
what lower than that of normal sea water, and the alkalinity some-
what higher.

The cause of the mortality in this region, as has been stated, has
not been determined. Foul water from the Everglades as a possible
cause may be dismissed, as well as all meteorological conditions.
Volcanic action is highly improbable, and attention need not be
turned to such a possibility from the evidence now at hand. /Pe7?-
dinii appear to furnish an exceedingly unlikely explanation, but
it is, perhaps, proper to reserve judgment, as the evidences contrary.
to such an explanation are not altogether convincing. A disease

alLater reports (April, 1917) from the Grampus indicate that the fishing was poor
through the winter season.

MORTALITY OF FISHES, WEST COAST OF FLORIDA. 23

seems to be a quite impossible explanation. Some geological, perhaps
seismological explanation, such as Prof. Woodworth suggests, ap-
pears to be the most promising possibility.

Aside from the continued recurrence of the phenomenon in the
past, we have no data on which to base a prediction as to future
recurrences. In the event of a verification of the seismological-
sedimentary hypothesis, a recurrence may be expected sometime.
In such an event oceanographic methods should be resorted to at
the first indication of the trouble; in the meantime a collection of
bottom and water samples over the region is desirable, and, if pos-
sible, gas bubbles, if present, should be collected from the mud by
appropriate apparatus.

BIBILIOGRAPHY.
Carter, H. J.

1858. Note on the red coloring of the sea round the shores of the Island
of Bombay. Annals and Magazine of Natural History, vol. 1, 3d
ser., no. 4, art. xx1m, p. 258-262, April, 1858. London.

CLARK, AUSTIN H.

1903. Notes on the habits of certain Venezuelan birds. The Auk, vol. xx,

no. 8, July, 1903, p. 285-286. Cambridge.
DARWIN, CHARLES.

1846. Researches into the natural history and geology of the countries
visited during the voyage of H. M. 8. Beagle round the world, under
the command of Capt. Fitz Roy, R. N., vol. 1, chap. 1, journal of
Mar. 18, 18382, p. 18-23. New York.

Gitcurist, J. D. F.

1914. An inquiry into the fluctuations in fish supply on the South African
coast. Union of South Africa, Province of the Cape of Good Hope,
Marine Biological Report no. 1, for the year ending June 30, 1914,
art. m, p. 8-35. Cape Town.

HutTcHinson, THOMAS J.

1873. Two years in Peru, with exploration of its antiquities, vol. 1, chap.

XI, p.-219-225. London.
INGERSOLL, ERNEST.

1882. On the fish mortality in the Gulf of Mexico. Proceedings of the
United States National Museum, vol. tv, for 1881, p. 74-80. Wash-
ington.

LertTcH, I.

1916. The function of hemoglobin in invertebrates, with special reference to
Planorbis and Chironomus larve. Journal of Physiology, vol. L, no.
6, p. 370-879. London and Cambridge.

Mean, A. D.

1898. Peridinium and the ‘ red water” in Narragansett Bay. Science, n. s.,
vol. viii, no. 203, p. TOT-709. Nov. 18, 1898; Garrison. (Also noted
in Report, United States Commissioner of Fish and Fisheries, 1899,
D: CXLIT.)

MITSUKURI, K.

1904. The culture of marine and fresh-water animals in Japan. Bulletin of
the United States Bureau of Fisheries, vol. xxiv, p. 384. Wash-
ington.

94 MORTALITY OF FISHES, WEST COAST OF FLORIDA.

NISHIKAWA, T.
1901. Gonyaulax and the discolored water of the Bay of Agu. Annotationes
Zoologicae Japonenses, vol. v, pt. 1, p. 31. Tokyo.
NORDENSKIOLD, A. E.
1882. The voyage of the Vega round Asia and Europe, with a historical
review of previous journeys along the north coast of the Old World.
Translated by Alexander Leslie, p. 246-247. New York.
OLDHAM, R. D
1899. Report on the great Indian earthquake of June 12, 1897. Memoirs of
the Geological Survey of India, vol. xxrx, p. 80. Calcutta.
SmMiTH, HucH M.
1903. Peridinium. (EHditorial article containing an extended quotation from
Dr. Smith.) Philippine Journal of Science, vol. 1, no. 38, p. 187.
Manila.
TANNER, Z. L.
1896. Report upon the operations of the United States Fish Commission
steamer Albatross for the year ending June 30, 1894. Report of
the Commissioner for the year ending June 30, 1894, p. 217-218.
Washington.

Brief notes have appeared in the publications of the Bureau of Fisheries 1m
previous years as follows: Rathbun, Richard (Fisheries and Fishery Industries,
sec. v, vol. 1, p. 831). Newspaper clipping (Bulletin, vol. m1, 1882, p. 104).
H. D. Pierce (letter, Bulletin, vol. rv, 1884, p. 264). Smith, H. M. (Bulletin,
vol. xviI, 1897, p. 284.) Moore, H. F. (Bulletin, vol. xxvii, pt. 1, 1908, p. 484).
Report for 1886 (p. 68-72).

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