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Tagging tuna and collecting data

Fishery scientists and fishers both practice their knowledge and observe tuna in the Sardinian

traps. Scientists collect data about tuna by inserting tagging devices or collecting samples

from tuna flesh. Scientists have practiced their knowledge in the traps since long before 2007

when observers became a compulsory part of the management and monitoring of tuna and the

traps. Since 1991 Piero Addis (fisheries scientist from the University of Caglieri) has

regularly visited the Sardinian tonnare (Emery 2010, p. 29). An initial scuba dive experience

ignited his interest in the biology and history of tuna and the traps (Emery 2010, p. 29). And

so, from 1993 to 2010 Addis has been the key investigator in a long-term analysis of

scientific data and standardised CPUE in the tonnare.

Fish tagging is central to fishery management and is used as a mechanism to collect

data about fish populations. It is an important part of the University of Caglieri’s research and

joins the activities of several ongoing tagging programs in the Mediterranean. ICCAT

facilitates some of these programs in collaboration with contracted institutions such as the

University of Caglieri. Addis’s team use “spaghetti” tags, often referred to as dart and anchor

tags or streamer tags, as they are long and thin and stick out from the fish’s body. They are

the most common, economical and easiest tag to apply (Atlantic States Marine Fisheries

Commission n.d.). The alternative is the 8,000 Euro tags fit with a GPS that releases

information once it has fallen off the fish. In contrast, the spaghetti tag relies on fishers to

recapture tuna and then to report the tag to authorities. Once handed to the appropriate fishery

authorities the tag can yield data about tuna, including population structure, movement

patterns and mortality rates.

Tagging activities began in the traps once the final transfer and mattanza were

complete: in other words once the cooperative had reached its 2013 quota. Equipped with

spaghetti tags and rifles and dressed in camouflage wetsuits, Addis and his team worked with

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