Large aggregations of Purpleback squid attributed to climate change

KARACHI: Climate change is playing an important role in the ecosystem dynamic of the Arabian Sea as fishermen have reported an unusual increase in the population of Purpleback flying squid in Pakistani waters during November 2016 to January 2017.

The fishermen have been sighting increase in the occurrence of oceanic (Sthenoteuthis oualaniensis), sometimes caught in their gillnets. In the beginning of this year, they located unprecedented concentration of this squid in offshore waters between 20o and 24o N both along Sindh and Balochistan coasts especially in the Khori Great Bank along Sindh coast and in off Malan along Balochistan coast.

This squid lives in open waters from the surface down to depths of around 1,000 m of ocean. It exhibits diurnal vertical migration and moves from deeper layers to surface or shallower waters during night.

Commenting on the development, Rab Nawaz, Senior Director Programmes, WWF-Pakistan stressed the need for studying long term changes in the oceanographic factors that may result in increase of certain species. Occurrence of bloom of jellyfish in December, 2016 and that of purpleback flying squid indicates that climate change is playing important role in the ecosystem dynamic of the Arabian Sea, he added.

Japanese Research Vessel “R/V Shoyo Maru” during the survey in 1975 located dense concentration of this squid about 90 nautical miles off Pasni Balochistan. They observed that purpleback flying squid seemed to inhabit the 120-200 m depth layers during daytime. A positive light attraction effect due to the vessels light was observed during night time. Acoustic survey revealed that the squids are widely and abundantly distributed in the offshore waters in the region. However, in 1976 this research vessel again conducted acoustic surveys but could not locate any such concentrations.

It is also interesting that in some other areas of Arabian Sea and Persian Gulf unprecedented occurrence of purpleback flying squid was observed during November and December 2016. Fishermen in Fujairah, U. A. E. caught large number of this oceanic squid in November 2016. Similarly, very high catches of this species were recorded from Oman.

From both these areas these squids were processed and exported. However, processing industry in Pakistan has not yet taken any such step for harvesting, processing and export of this squid.

Muhammad Moazzam Khan, Technical Advisor (Marine Fisheries) WWF-Pakistan pointed out that abundant occurrence of purpleback flying squid in the Arabian can be attributed to long term changes in oceanic regime.

‘Climate change may have also influenced the unprecedented appearance of the oceanic squids in Pakistani waters. As this species is found in abundance, therefore, there is an opportunity for the Pakistan’s fisheries industry to gear up for exporting this high priced commodity to Far East Asian countries.’