Seis­mic pres­sures

The Southern Gazette - - Editorial -

The fish­ery should be re­new­able; the oil in­dus­try clearly is not. So, if ac­tions we’re tak­ing to sup­port the oil in­dus­try could be af­fect­ing the fish­ing in­dus­try, we clearly should be in­vest­ing the time and ef­fort to un­der­stand the pos­si­ble im­pli­ca­tions in­stead of sim­ply mov­ing for­ward.

There have al­ways been ques­tions about the dam­age that oil in­dus­try seis­mic work might be do­ing on ma­rine or­gan­isms - yet off this prov­ince, seis­mic work has not only grown, but has oc­ca­sion­ally been taken on and paid for by provin­cially owned Nal­cor En­ergy.

It’s prac­ti­cally be­come a point of pride for the gov­ern­ment, which has boasted about seis­mic pro­grams be­ing the largest un­der­taken, and even as be­ing un­ri­valled in the mod­ern ex­plo­ration era.

But there are ques­tions about whether the test­ing might be dam­ag­ing some­thing as ba­sic as plank­ton - the ba­sic food source at the bot­tom of the oceanic food web. In other words, the food that most ma­rine species de­pend on.

The test­ing is done by the use of com­pressedair blasts that are loud enough to travel down through wa­ter and the ocean floor to lo­cate po­ten­tial oil and gas fields - seis­mic ves­sels fire the com­pressed air guns ev­ery few sec­onds and then gather in­for­ma­tion on how the sound is re­flected back to sen­sor ar­rays towed be­hind the ves­sels.

But a study in the jour­nal Na­ture - Ecol­ogy and Evo­lu­tion from June of 2017 raises some in­ter­est­ing ques­tions.

It’s prac­ti­cally be­come a point of pride for the gov­ern­ment, which has boasted about seis­mic pro­grams be­ing the largest un­der­taken, and even as be­ing un­ri­valled in the mod­ern ex­plo­ration era.

This is from the study’s ab­stract: “Ex­per­i­men­tal air gun sig­nal ex­po­sure de­creased zoo­plank­ton abun­dance when com­pared with con­trols ... and caused a two-to three­fold in­crease in dead adult and lar­val zoo­plank­ton. Im­pacts were ob­served out to the max­i­mum 1.2 km range sam­pled, which was more than two or­ders of mag­ni­tude greater than the pre­vi­ously as­sumed im­pact range of 10 (me­tres). Although no adult krill were present, all lar­val krill were killed af­ter air gun pas­sage. There is a sig­nif­i­cant and un­ac­knowl­edged po­ten­tial for ocean ecosys­tem func­tion and pro­duc­tiv­ity to be neg­a­tively im­pacted by present seis­mic tech­nol­ogy.”

Cou­ple that with some­thing else: as the vol­ume of seis­mic work has in­creased - maps of the work show vast ar­eas of ocean crossed and criss­crossed with the ves­sels’ tracks - oceanic plank­ton lev­els off New­found­land and Labrador have de­clined dra­mat­i­cally.

In fact, the plank­ton abun­dance num­bers have dropped over the last five years by as much as 50 per cent.

There could be a myr­iad of rea­sons for the drop; the con­tin­u­ing acid­i­fi­ca­tion of the oceans might be af­fect­ing the abil­ity of plank­ton that use cal­cium to hold their struc­ture to sur­vive. Rapid tem­per­a­ture change might also be af­fect­ing their abil­ity to sur­vive.

But fish­eries sci­ence is sup­posed to be based on the pre­cau­tion­ary prin­ci­ple.

Per­haps we should be look­ing at more re­search, rather than trum­pet­ing more seis­mic work.

Newspapers in English

Newspapers from Canada

© PressReader. All rights reserved.