22 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 exap''^'eration to 

 assert that the number of fishes that perished would be sufficient 

 to supply the State of Florida for a season Yet a few Aveeks 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. 



It 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. Peri- 

 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 



a Later reports (April, 1917) from the Ornmpus indicate tliat the fishing was poor 

 through the winter season. 



