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migrations: they occur at depths of about 200–700 m during the day, and then at the
onset of twilight and increasing darkness, they ascend into the uppermost 200 m for
the night. A deeper-living layer of diel migrators occurs from about 1000 to 600 m
during the daytime. The abundance of squids varies, depending on genera, habitat
and season, from isolated individuals, small schools with a few dozen individuals,
to huge schools of neritic and oceanic species with millions of specimens (Jereb and
Roper 2010). The squid, characterized by short life spans and rapid growth rates,
can more easily react to changes in the environment and tropical structure than other
mid-trophic organisms in the open ocean (Young et al. 2013).
Production and Trade of Squids
After 5 years of continuous growth that started in 2010, catches of cephalopods
were stable in 2015 but dropped in 2016 when catches of the three major squid species showed a combined loss of 1.2 million tonnes. The three major squid species
(jumbo flying squid (Dosidicus gigas), Argentine shortfin squid (Illex argentinus)
and Japanese flying squid (Todarodes pacificus)) decreased by 26%, 86% and 34%,
respectively, for a combined loss of 1.2 million tonnes between 2015 and 2016
(FAO 2018).
It is reported that squid fishing has increased significantly in the world and has
almost doubled compared to 30 years ago. Historically, Japan has always been at the
forefront of squid production and consumption, but it is reported that in 2016, China
became a leader in squid fishing, but Japan maintained its leadership position as a
consumer (Arkhipkin et al. 2015). There was a significant increase in Japanese
imports of squid and cuttlefish, from 111,000 tonnes during the first three quarters
of 2016, to 133,300 tonnes during the same period in 2017 (FAO-Globefish 2018b).
Squid catches have increased substantially worldwide, and this has highlighted
the fact that their populations are highly variable. The Illex illecebrosus fishery in
the northwest Atlantic which was developed very rapidly by the East Asian squid
jigging fleet in the late 1970s and early 1980s, following a decline of Todarodes
pacificus in the northwest Pacific, collapsed suddenly and led to a rapid switching
of effort to the southwest Atlantic in the early 1980s to target Illex argentinus.
Subsequently catches of Todarodes pacificus have continued to fluctuate but the
fishery for Illex illecebrosus has never returned to Canadian waters although consistent, but lower, catches are taken off the eastern USA further south (Rodhouse 2005).
The giant squid (Dosidicus gigas) stocks off Peru and Chile appear to be suffering. Since June 2017, these fisheries have collapsed, and supplies have been scarce.
The reason is thought to be the effect of El Niño, which led to a complete fishery
stop also in 2016. The collapse of the giant squid fishery has brought on an initiative
to assess the giant squid biomass. Giant squid is the second largest fishery in Peru,
and consequently of great economic importance to the country. After recent years of
scarce squid landings in California due to the El Niño effect, fishing is now improving. The arrival of La Nina with colder waters reaching southern California has
brought the squid back. Since October, fishing has improved somewhat. In the
3 Molluscan Shellfish
migrations: they occur at depths of about 200–700 m during the day, and then at the
onset of twilight and increasing darkness, they ascend into the uppermost 200 m for
the night. A deeper-living layer of diel migrators occurs from about 1000 to 600 m
during the daytime. The abundance of squids varies, depending on genera, habitat
and season, from isolated individuals, small schools with a few dozen individuals,
to huge schools of neritic and oceanic species with millions of specimens (Jereb and
Roper 2010). The squid, characterized by short life spans and rapid growth rates,
can more easily react to changes in the environment and tropical structure than other
mid-trophic organisms in the open ocean (Young et al. 2013).
Production and Trade of Squids
After 5 years of continuous growth that started in 2010, catches of cephalopods
were stable in 2015 but dropped in 2016 when catches of the three major squid species showed a combined loss of 1.2 million tonnes. The three major squid species
(jumbo flying squid (Dosidicus gigas), Argentine shortfin squid (Illex argentinus)
and Japanese flying squid (Todarodes pacificus)) decreased by 26%, 86% and 34%,
respectively, for a combined loss of 1.2 million tonnes between 2015 and 2016
(FAO 2018).
It is reported that squid fishing has increased significantly in the world and has
almost doubled compared to 30 years ago. Historically, Japan has always been at the
forefront of squid production and consumption, but it is reported that in 2016, China
became a leader in squid fishing, but Japan maintained its leadership position as a
consumer (Arkhipkin et al. 2015). There was a significant increase in Japanese
imports of squid and cuttlefish, from 111,000 tonnes during the first three quarters
of 2016, to 133,300 tonnes during the same period in 2017 (FAO-Globefish 2018b).
Squid catches have increased substantially worldwide, and this has highlighted
the fact that their populations are highly variable. The Illex illecebrosus fishery in
the northwest Atlantic which was developed very rapidly by the East Asian squid
jigging fleet in the late 1970s and early 1980s, following a decline of Todarodes
pacificus in the northwest Pacific, collapsed suddenly and led to a rapid switching
of effort to the southwest Atlantic in the early 1980s to target Illex argentinus.
Subsequently catches of Todarodes pacificus have continued to fluctuate but the
fishery for Illex illecebrosus has never returned to Canadian waters although consistent, but lower, catches are taken off the eastern USA further south (Rodhouse 2005).
The giant squid (Dosidicus gigas) stocks off Peru and Chile appear to be suffering. Since June 2017, these fisheries have collapsed, and supplies have been scarce.
The reason is thought to be the effect of El Niño, which led to a complete fishery
stop also in 2016. The collapse of the giant squid fishery has brought on an initiative
to assess the giant squid biomass. Giant squid is the second largest fishery in Peru,
and consequently of great economic importance to the country. After recent years of
scarce squid landings in California due to the El Niño effect, fishing is now improving. The arrival of La Nina with colder waters reaching southern California has
brought the squid back. Since October, fishing has improved somewhat. In the
3 Molluscan Shellfish