Monthly Archives: September 2015

August 2015: Bluefin Tuna at the Kinki University Fisheries Laboratory, Kushimoto, JAPAN

*Articles on the story below are due to appear in Intrafish Media’s Fish Farming International magazine ( and the UK’s The Fish Site ( in October. The Laboratory’s work will be covered in more detail, accompanied by plenty of quotes from Professor Sawada and Professor Kato. A big thank you to both Professors for taking the time to show me around! 

Friday August 21st, 2015

In August 2015, I was honoured to visit the Fisheries Laboratory of Kinki University in Kushimoto, Wakayama Prefecture and see its farming operations for myself.  The Laboratory has become known for its work to address the problem of rapidly declining wild tuna populations and in 2002 became the first in the world to cultivate completely farm-raised Pacific bluefin tuna. 

Cultivate the seas!” It was under this philosophy that the Fisheries Laboratory of Kinki University began. After Japan’s defeat in the Second World War, Koichi Seko, the first president of the university, believed Japan would have no future unless people cultivated the seas and more seafood was produced, so he founded the Laboratory in 1948 by first establishing a seaside research facility in the town of Shirahama in Wakayama Prefecture. Bluefin tuna farming began in 1970 with the fishing of small juveniles off the prefecture’s coast, and in 2012, 70,000 – 80,000 young fish were successfully produced.

During my visit I spoke to Professor Yoshifumi Sawada, Director of the Laboratory’s Oshima Experiment Station, and Professor Keitaro Kato, deputy head of the Laboratory’s Shirahama Station, who explained the concept of “full-cycle aquaculture,” in other words “raising artificially hatched larvae to adults, collecting their eggs and hatching them to create subsequent egg-laying generations.” We covered vast areas ranging from circular cages on the surface of the water that are used to grow the tuna, to the pros and cons of fishmeal and alternative diets such as those including plant protein.  We also discussed biosecurity, disease prevention and touched upon collisions, which is apparently just as serious a problem as disease.  The large size of tuna — they can grow up to 350kg — can get the fish into trouble with fast-moving tuna-on-tuna collisions inside large farming pens.  These collisions can sometimes have fatal consequences.

Sawada and Kato also described the many challenges and obstacles, including research into alternative feeds to reduce the amount of fishmeal and make operations more sustainable.  One of their very first challenges was to increase survival rates from harvested eggs to hatchlings, and preventing death among the larvae also requires further research. Despite these however, Sawada is confident that their work will contribute to reducing pressure on natural tuna stocks.  “Thanks to our control over all aspects of the bluefin tuna lifecycle,” he told me, “we can offer a stable supply of tuna without depending on fish stocks in the wild.”

The Laboratory’s work is being funded via a business model in which farmed tuna is sent to restaurants owned by the Laboratory in Tokyo and Osaka.  The profits are then used to fund further research and development. Sawada and Kato’s team is also working on getting its farmed population up, and mapping the entire DNA of tuna through blood samples to isolate the best DNA characters for disease resistance, growth and sex identification.

As global populations of bluefin tuna continue to decline because of worldwide demand, the Laboratory’s work couldn’t be more welcome, but only time will tell whether farmed tuna is the way forward.

August 2015: The Kooza River, Kushimoto, Wakayama Prefecture, JAPAN

Saturday August 22nd 2015

Due to the popularity of ocean diving freshwater is often overlooked, but Kushimoto in Wakayama prefecture is home to one particular river where all kinds of freshwater adventures can be had.  The Kooza River provides some fantastic dives with super clear water, incredible landscapes and a range of cool critters to discover, not to mention the added bonus of not having to wash any gear or camera equipment after leaving the water. It may not be well known as a diving spot but the Kooza River has very easy diving in a great location.  It offers many interesting species to search for below the water, and plenty to keep non-divers occupied — think swimming and BBQs by the river bank!

Heading into the water can be a shock at first as the water can feel quite cold, but the drawcard for divers is the unexpected abundance of stones and pebbles and a huge shallow area (no deeper than around 5m) that seems to stretch for miles. Heading across to the other side of the river, you soon arrive at some huge rocks and boulders. The bottom is covered in more tiny pebbles, a few green plants and a thin layer of sediment and organic materials, and it soon becomes clear that the Kooza River really does have it all, from tiny macro miniature delights like small crabs to clear water teeming with fish life.  There are great rocky slopes and plenty of macrolife beneath them, which would satisfy any freshwater diver.

In flat calm water, basking in sunshine, we dropped down onto the series of stones and pebbles to explore further, while river fish that appeared to be sweetfish glinted in the sunlight near the surface.  Huge healthy-looking shrimp emerged from their lairs in the rocks, looking around with curiosity, while crabs hid in the nooks and crannies, sometimes with small goby-like fish resting close by and darting out of sight at the slightest provocation.  We were spoiled with a good few photo opportunities, and spent ages hovering over the carpet of pebbles snapping everything and anything we could find.  The highlight of the dives was the sheer number of pale chubs, a common fish in Japan’s rivers.  With distinguishing features such as long ventral fins and protruding mouths, pale chubs are said to be related to carp and have good jumping skills, which allow them to grab bugs hanging around near the surface of the water.  They’re also said to be highly active and are tenacious survivors.  During mating season, the male’s stomach turns pink and its back turns blue. We were extremely fortunate to witness the pale chub’s egg laying, and thanks to the shallow depth, managed to spend hours lying over the pebbles taking photo after photo.

Because of a lack of tides and currents divers of all levels can enjoy the Kooza river, but as visibility can sometimes turn poor, things such as a dive light and proper finning techniques (so as not to disturb the bottom) should be taken into account.  Freshwater tends to be cold, so make sure you have the right kind of exposure suit for the water temperature.  Otherwise, the Kooza river is a refreshing and very enjoyable site with many favourable aspects such as great water clarity, abundant shallow formations with ample ambient light, a range of diverse and dramatic topographies and the well-protected quality of the area itself.

Practical Information 

  • I flew to Nanki Shirahama from Tokyo’s Haneda airport with JAL at 07:25AM arriving at Shirahama around 08:40AM.  I was then met by a representative from Kinki University and driven to Kushimoto for work purposes. A single plane ticket costs around 30,000yen.
  • I was dropped off at JR Kooza station next to Kushimoto and stayed at the shop Dive Kooza ( which has bunk beds, showers, toilets, towels, hairdryers, shampoo and body soap available. A night’s stay costs 2,000yen.  It’s extremely comfortable, with a big indoor space to write up log books, have a coffee or relax and go over photos or books on marine life. You can also connect a computer to their bigger screen when looking at your photos. There are areas to sit outside if the weather is nice, and a convenience store a short walk away for food, drink, snacks and other daily items. Right next to it are places to wash, dry and hang equipment, and a parking area for vehicles. Cameras/lens can also be hired.
  • The Kooza River is about 30mins away by car from Dive Kooza.  Divers set up at the shop and carry their gear to the riverbank on arrival.
  • One dive costs around 7,000yen (two boat dives with Dive Kooza come to around 14,000yen).
  • Anyone wishing to stop on the way to buy snacks etc can do so en route.
  • I travelled back to Tokyo by train, starting at JR Kooza station and ending at JR Shirahama station.  The journey on a local train (there were less trains due to a typhoon) took about 1.5 hours.  From JR Shirahama station there is a fast train direct to Shin Osaka station that takes about 2.5 hours and costs around 5,600yen for a single ticket.  The bullet train platform is just upstairs, from which there are regular trains to Tokyo for around 14,000yen for a single ticket.  Journey time is around 2.5 hours.
  • A weekend of diving in Kushimoto can be arranged through David Graham at Kansai Divers ( Check out their Facebook page as well. Tours can be arranged with Dive Kooza and non-Japanese speakers are also welcome!

August’s dives 

Dive 1: Nukumi (The Kooza River): dive number: 193, depth: 5.3m, dive time: 41 mins, entry time: 10:20, exit time: 11:01, water temp:23C, water visibility 5m (max depth), start pressure: 180 bar, end pressure: 100 bar, used a 10L steel tank, 5mm wetsuit, 3kg back plate, 1kg extra weight in pocket (more buoyant in freshwater), 3mm hood/vest.  Saw sweetfish, pale chubs, cyprinid fish, amur gobies, pond loaches, shrimps and crabs.

Dive 2: Nukumi (The Kooza River): dive number: 194, depth: 5.5m, dive time: 42 mins, entry time: 11:12, exit time: 11:50, water temp: 23C, water visibility: 5m (max depth), start pressure: 100 bar, end pressure: 50 bar, used a 10L steel tank, 5mm wetsuit, 3kg back plate, 1kg weight in pocket (more buoyant in freshwater), 3mm hood/vest.  Saw sweet fish, pale chubs, cyprinid fish, amur gobies, pond loaches, shrimps and crabs.

August 2015: Diving off Dogo, The Return to the Oki Islands

Monday August 10th – Tuesday August 18th 2015 

Scattered about in the Sea of Japan, just off Shimane Prefecture, are four inhabited and 180 uninhabited islands.  To many people, they’re a mystery. Often confused for Okinawa because of their name, the Oki Islands are perhaps a great example of what Japan might have been like in the past. With fishing, seafood (squid, turban shell and rock oyster to name a few) and spectacular natural scenery, they are steeped in history, tranquility and charm, a place yet unaffected by the hustle and bustle of a huge metropolis.

It’s precisely this that draws me to this charming destination.  I first visited the Oki Islands in October last year after receiving an invitation from the local tourist association to write an article on diving there.  One article soon became several, and as I returned this time, I spent 8 days diving off Dogo, the largest island of them all.

Sheer colossal cliffs are one of Dogo’s most noticeable features.  Rising up from the ocean, years of rough waves have carved them into what they are today.  The underwater scenery is just as fascinating, with a range of currents, temperate and tropical species.  Beds of seaweed and clusters of soft coral sway to and fro, while schools of fish swim around in the distance.  Huge dynamic rocks abound, offering divers a unique and interesting underwater topography.  Here are some of Dogo’s dive sites that are well worth a visit:

Oki no Tatami: 10minutes away by boat from the dive centre’s shores is Oki no Tatami.  With a backward-roll splash, we descend onto a huge rock that sits on a carpet of white sand at around 25m.  The deeper we go, the more the rock takes recognisable shape from the greenish blue which I’d been focusing on at the start of the dive.  Visibility isn’t great, but it’s good enough to immediately spot a school of damselfish.  Those who enjoy macro photography will enjoy Oki no Tatami, where the current is mild and there is not much in the way of pelagic fish.  The underwater terrain mirrors the high, steep cliffs that exist topside, and upon closer inspection of the rock, crabs and blennies peer from every crevice while barrel sponges draw near and recede.  The bottom can lack obvious signs and the medium-sized rocks scattered around close by make it easy to lose your bearings, so the best way to explore this site is to spend time circling close to the huge rock itself, a journey which takes no more than around 30mins. As well as the schools of damselfish, some highlights are a variety of bennies that look like frogs, poking their heads out from their lairs in the rock, with feathery tentacles above the eye.  I encountered chicken grunts, schools of young yellowtail and even a couple of red sea bream drifting slowly by.  The diving experience exploring the many nooks, crannies and little holes is well worth the exercise here, even though the fish escorts aren’t always present.

Iibiguri: This is a point reserved for advanced divers who enjoy the challenge of deeper depths and currents (an Advanced Open Water certification is a minimum requirement). Iibiguri’s range of pelagic and large schools of fish are a sharp contrast to the rocks and macro life of Oki no Tatami but these vastly different dive locations complement each other well.  Iibiguri lies about 15mins from shore in the open sea, and the fairly strong currents make it extremely rich in marine life and a must-dive spot for anyone visiting Dogo.  We descend along a rope to 16m and gather at a small ledge before clinging to it, chuffed with our front-row seats as we wait for something, anything, to emerge out of the blue. The edge forms part of a gigantic rock, and depending on the direction of the current, the dive involves exploring this structure to about 40m before returning to the ledge and making the ascent. The best way to enjoy this site is to feel the current and take in what’s around you.  We saw several calm red sea bream, schools of pearl-spot chromis, Hong Kong groupers, striped beakfish and a few spotted knife jawfish.  Each side of the rock drops precipitously into the deep blue and seems full of coral, such as small whip coral and soft coral. Chicken grunts and angelfish zipped around while spotted morwongs and tawny groupers glided by.

Aka Beach/Kazemachi Beach: Plunging into the clear water, I descended down one of the most spectacular walls right next to the dive shop.  It seemed that a fest of colours greeted me with seaweed, sponges and soft coral painted in an array of different shades.  I glided down to 5m soaking up the fantastic vista.  As I went deeper, I found more and more small rock formations over the sand, covered in an amazing range of  growth.  As I returned to the shallows, I focused on looking for tiny critters and boulders close to the surface. This is an extremely easy and relaxing dive that’s shallow and close to shore so divers can spend a great deal of time getting lost in a world of biodiversity and discovery.  At one point I was treated to an octopus poking out of a small crevice on the descent before hastily making a getaway, and encountered friendly fish of all shapes and sizes such as pearl-spot chromis, a couple of rockfish that didn’t seem to mind as I leaned in close for some photos, and some very relaxed flatfish lying amongst the sand particles.  There are tiny macro miniature delights and colourful crinoids grazing off the rocks, such as nudibranchs, sea slugs, crabs and a beautiful white seahorse that lives at a depth of just 3m. For divers who love macro life, this is surely one of Dogo’s best underwater environments.

Practical Information

  • I took a flight with JAL around 08:00AM on Monday 10th August from Tokyo’s Haneda Airport to Izumo Airport, and then took another flight around 09:40AM from Izumo airport to Oki airport, which takes about 30mins.  A round trip with this route is about 70,000yen.
  • I spent 8 days diving with Fuse Diving Center ( on Dogo. The shop is located right on the waterfront. It’s old, very spacious, with hot showers outdoors and shampoo/conditioner and shower gel provided in two indoor showers. There is a spacious indoor area to look through dive magazines or write up log books. The boat is in good condition, and all dive sites are within 15mins away from the mainland. Free coffee is available, as well as a spacious outdoor area to wash and dry gear.
  • Tanks and gear are stored in the middle of the boat while divers sit around that area. There is also a roof over the tanks that divers can sit under too to avoid the sun.
  • All entries into the water are backward rolls. Ascent is up a ladder.
  • On Dogo I stayed at a traditional Japanese inn (minshuku) called Mizuoka, about 15mins away from Fuse Diving Center. A family-run place, although dinner is not available, the breakfast (rice, miso soup, eggs, fried fish and vegetables with green tea) is basic and healthy.  The minshuku has a bath/shower, shower gel, shampoo and towels available for use.  (The owner is a big worrier, and myself and a couple of other divers had a good laugh over that!) Fuse Diving Center can help with accommodation arrangements.
  • For further details, please contact Nicola Jones at the Nishinoshima Tourism Office (( to arrange accommodation, transport and diving off Nishinoshima for non-Japanese speakers.  Information on Dogo, including diving, is available from Teresa Sadkowsky at the Oki Islands Global Geopark (
  • Please also see my blog entry ( on diving off Nishinoshima and Dogo in 2014.

October’s dives (these are just some of the dives undertaken during my 8-day stay)

Dive 1: Oki no Tatami: dive number: 183, depth: 18.8m, dive time: 41mins, entry time: 17:07, exit time: 17:48, water temp: 26C, water visibility: 10m, Start pressure: 200 bar, End pressure: 50 bar, used a 10L steel tank, 5mm wetsuit, 3kg weight (plate) and 1kg extra weight in pocket. Saw chicken grunts, pearl-spot chromis, rock fish, red sea bream, damselfish and striped beak fish.

Dive 2: Iibiguri: dive number 185, depth: 40.6m, dive time:33mins, entry time: 11:27, exit time: 12:00, water temp: 26C, water visibility: 10m, start pressure: 200-210 bar, end pressure: 50 bar, used a 10L steel tank, 5mm wetsuit, 3kg weight (plate) and 1kg extra weight in pocket.  Saw schools of yellow tail, striped weakfish, angelfish, chicken grunts, spotted tail morwongs and spotted knife jawfish

Dive 3: Aka Beach/Kazemachi Beach: dive number 186, depth: 10.5m, dive time: 82mins, entry time: 15:38, exit time: 17:00, water temp: 29C, water visibility: 15m, start pressure: 210 bar, end pressure: 50 bar, used a 10L steel tank, 5mm wetsuit, 3kg back plate (no extra weights), saw octopus, rock fish, flatfish, white seahorse, nudibranchs, starfish, pearl spot chromis, rock fish and sea slugs.