Republished from Radio New Zealand, 27 December 2019
by Giff Johnson
Majuro – Despite millions of pounds of tuna transhipped through Pacific island ports, nobody has a precise count of the tonnage.
The entire system for both industry and island fisheries managers revolves around estimates of the tonnage – a deficiency the Marshall Islands Marine Resources Authority (MIMRA) is attempting to remedy.
“Knowing how much fish a purse seiner really caught is not an easy task, not for industry or for the authorities,” said Francisco Blaha, the Offshore Fisheries Adviser at MIMRA in Majuro.
“Traditional scales don’t work on board, and getting fish into low temperatures as soon as possible is fundamental for food safety and quality particularly when you have a big set of over 100 tons in the water.”
As a result, tuna boat captains and fisheries observers work on estimates. “While they are very good, it is still an estimate,” said Mr Blaha. “Only once the fish is unloaded for ‘weigh in’, generally at the cannery, or sometimes before containerisation do we get to know the real verified weights.”
But, he added, this often happens months after the tuna is caught, and the catch tonnage data may never actually be seen by the island fisheries managers.
Mr Blaha, an experienced commercial fisher whose position in Majuro is supported by the New Zealand Ministry of Foreign Affairs and Trade, said this has negative implications for stock assessments and fisheries assessments, but also financial impacts for the fishing crew.
Gaining accurate weights is good for everyone since “weights are fundamental and benefit all sorts of fisheries decision making”, said Mr Blaha, who ticked off those interested in catch weights: crew and skipper who are paid partly based on the volume of fish caught; vessel managers who deal with profitability and insurance issues; carrier vessels that deliver the tuna to canneries; and scientists and regulators who generate stock assessments and advice about allowable catch levels. “Quite simply, the more accurate the data, the better decision making,” he said.
Majuro is currently the busiest tuna transhipment port in the world, with over 400 purse seiners annually transshipping about 300,000 tons of tuna. The process of transferring between 800 and 1,700 metric tons of fish from purse seiner to carrier vessel can take up to a week and involves putting the frozen fish in nets and hoisting them into the carrier from the deck of the purse seiner.
MIMRA science and boarding officers saw transhipment operations as an excellent opportunity to verify the weights caught by purse seiners by weighing each the of the nets with frozen fish as they are transshipped using hanging scales attached to the hooks of the cranes used during the operation.
MIMRA gained support from the Forum Fisheries Agency (FFA) and Pacific Community (SPC) to research the feasibility of the concept and to evaluate what type of hanging crane scales will do the job best.
Last month, MIMRA started what is believed to be a world-first research program to determine the best system for weighing fish coming off a purse seiner to a carrier vessel. A team composed of FFA, SPC and MIMRA people launched the testing of four different types of remotely operated electronic crane scales during the transshipment of a Marshall Islands flagged tuna vessel.
Mr Blaha said they evaluated each model against attributes such as precision, robustness and ease of use, battery performance, recyclability, and price and connectivity.
“The results will benefit not only the Marshall Islands but the whole region as there is transshipment activity in Kiribati, Federated States of Micronesia, Tuvalu, Papua New Guinea and Solomon Islands,” said Mr Blaha.
The work is expected to continue in 2020 with the general aim of standardizing the use of crane scales for monitoring the weights of all tuna transhipped in the region. It has additional benefit for management and data acquisition for port monitoring operations, he said.