Mass mortality of anchovy at Ex Ballenera Iquique, Chile

Mass mortality of anchovy at Ex Ballenera Iquique, Chile

October 16, 2016

Masatoshi Futagawa

There are many anchovies washed shores at Ex ballenera Iquique Chile on the afternoon October 15, 2016. Those anchovy show weak condition, still alive when the fish reached to the beach. It smelled rotten fish odor and many birds gathered at the area who take those anchovy. The same incident occurred that 600 ton of anchovy dead at Oueule, south of Chile, on last July. Additionally, we observe many birds at surface along Iquique coast that suggest possibly same incident occurring since last month. 

 

 

I collected some live samples, 4 males and 4 females (TL 12 – 13 cm) at the beach. Based on the optical observation, not using microscope, the fishes show clean and fresh gills and matured, gonad color orange, and intestine has contents.

    

   

According to the observation, suspected reasons of the incident are as follows.

1.      Not water contamination of chemicals: It needs thousands of tons of chemical  making weak condition of fish at open sea. Also, other costal animals do not show any negative signs even other kind of fish at the coast.

2.      Low possibility by toxic planktons: There are no negative signs of coastal animals such as birds and seals those take anchovy and concentrate toxicity inside body.

3.      Not cause of mass propagation of phytoplankton, red tide, or parasite contamination at gills and skin: The gills show red and clean condition, not show white gills or mucus on skin, that mention to no occurring of anoxia or parasite propagation.

4.      Low possibility of bacterial or virus affection: The fish has appetite and show intestine contents and show dark red color liver.

5.       Not big predator chasing anchovy and force to landing: There are no any observation of sea animals such as dolphin and whale.

I concluded that cold water mass, different salinity, came up from deep sea irregularly that originally from Antarctica through Humboldt Current, and anchovy got temperature shock then reduce swimming ability. The incidents not only reduce present biomass but next generation biomass after 6 month. Cold water mass kill mature broodstock and hatch-out larvae. Recently there are few regular size anchovy and closed fishing few months at north of Chile. It might be same incident happened before.

We need more study that monitoring water temperature by data logger, diagnosis of fish, analysis plankton. Also, gathering basic biological data such as growth, oxygen consumption, food consumption, water temperature resistant under laboratory condition.