(YOMIURI SHIMBUN/ASIA NEWS NETWORK) In Toyama Bay, it is just about prime fishing season for hotaruika, otherwise known as firefly squid.

Already well known for its rich flavour, which goes well with vinegared miso or pickled in a soy sauce-based mixture, the squid has also attracted attention in recent years for its high nutritional value.

Once spring arrives, hotaruika come to Toyama Bay to spawn. Namerikawa, Toyama Prefecture, boasts the largest haul of the squid in the prefecture. Local fisherman Kazuhito Mizuhashi said they "try to maintain the resource" by catching firefly squid when they return to the deep sea after spawning.

In early March, this reporter was offered a ride on a boat heading out for fixed-net fishing. The job involved a "parent" vessel and "child" vessel working in tandem.

The boats left port amid complete darkness at 3.30am to head for a spot one to two kilometers out at sea. First, the child vessel closed the net's opening and took a position facing the parent vessel with the net between them. Next, the fishermen carefully pulled the net in by hand so as not to damage the hotaruika.

That day, the haul included more than 3kg of firefly squid and a large number of sardines as well. The vessels returned to port by 5am, where the catch was immediately bid on and sent for processing. The hotaruika season peaks at around April and lasts until June.

Hotaruika have roughly the same amount of vitamin A as kabayaki grilled eel fillets, according to research by Toyama College Prof. Hiroyuki Takeuchi. The squid are also rich in vitamin B12, which helps prevent anaemia, and taurine, which strengthens liver function.

The Toyama-ken Hotaruika Kyokai, an association made up of local fishermen and others, encourages consumers to eat firefly squid on the mid-spring Day of the Ox, which falls on April 27 this year. (The midsummer Day of the Ox is traditionally considered the day to eat grilled eel to survive the sizzling heat.)

"It's great to eat hotaruika around when the seasons change, which is when people tend to get sick," said Ryoji Tanaka, an executive at the Toyama prefectural federation of fishing cooperatives. "In addition to popular cooking methods, such as boiling them in salted water, you can also add them to pasta or pizza."

Now there is a new addition: eating hotaruika raw as sashimi. However, due to reports that parasites have been found in their internal organs, the Health, Labor and Welfare Ministry recommends eating the squid after its internal organs have been removed, or after it has been frozen for at least four days at minus 30 C or lower.

The Hotaruika Museum, located next to the Namerikawa Port, houses the restaurant Kosai, which is serving both variations of hotaruika sashimi until April 13. Priced at ¥3,000 (S$37), the set item is available for 10 customers each day. The thawed frozen version had a pleasant, slightly hard texture with a rich flavour, while the kind without organs had a firmer texture.

Hotaruika caught off Toyama Prefecture are usually boiled in salted water before being shipped nationwide, while some vendors deliver frozen squid.

Boat services that let tourists see hotaruika being caught are available through May 6 in Namerikawa. Visitors can also get a firsthand look at how hotaruika emit blue fluorescent light at the Hotaruika Museum, as freshly caught squid are on display there throughout the season.