4165 x 2780 px | 35,3 x 23,5 cm | 13,9 x 9,3 inches | 300dpi
Data acquisizione:
14 marzo 2016
Ubicazione:
Salish Sea Pasrksville, Vancouver Island BC Canada..
Altre informazioni:
Pacific herring have a bluish-green back and silver-white sides and bellies; they are otherwise unmarked. The silvery color derives from guanine crystals embedded in their laterals, leading to an effective camouflage phenomenon. herring is a forage fish widely considered to be a keystone or foundation species because of its huge productivity and wide interactions with a range of predators and prey. Preferring to spawn in sheltered bays and inlets, the adult herring begin making their way from the open ocean to the spawning grounds in the late winter. When the time comes to spawn, a single female may lay as many as 20, 000 eggs, producing a staggering egg density of 6 million eggs per square metre. The resulting pulse of biomass attracts a huge array of predators including sea lions, humpback whales, wolves, bears and a host of bird species. Individual fish may return to spawn up to 10 times in their lives. First Nations have a long history of sustainably harvesting herring roe for trade and consumption using a method that involves collecting eggs that have been deposited on kelp or hemlock branches suspended near the shore. Such a method allows the spawning herring to live on and spawn again or be eaten by predators, therefore maintaining the herring’s critical ecosystem function. The traditional First Nations spawn on kelp (SOK) fishery involves the suspension of hemlock branches, kelp fronds, and seaweeds in sheltered spawning areas. Female herring lay eggs in multiple layers on the leaves. When harvesters collect the SOK, the adult fish are left to spawn again in the future. In contrast, the “sac roe” fishery, industrial seine and gillnet boats net schools of herring just before spawning. The roe, which is only 12% of the catch on average, is removed from the female fish for export to Japan. Most of the carcasses from the male and female fish are processed into feed for Atlantic salmon raised in open net-pens, which jeopardize B.C.’s wild salmon populations.
