Catch per Unit Effort Dynamic of Yellowfin Tuna Related to Sea Surface Temperature and Chlorophyll in Southern Indonesia

Budy Wiryawan,Irfan Yulianto,Prihatin Wahyuningrum,Sonja Kleinertz,Putra Timur,Neil Loneragan,Wildan Wildan,Jessica Pingkan,Ulfah Mardhiah,Deirdre Duggan

doi:10.3390/fishes5030028

Abstract

Tuna fisheries are the most valuable fisheries in the world, with an estimated market value of at least US$42 billion in 2018. Indonesia plays an important role in the global tuna fisheries and has committed to improve its fisheries management; therefore, a pilot of long-term spatial-temporal data bases was developed in 2012, however none have utilized data to have better understanding for management improvement. In this study, the annual and seasonal variation of large (≥10 kg) Yellowfin Tuna (YFT) catch per unit effort (CPUE) have been investigated and the influence of sea surface temperature (SST) and chlorophyll-a on these variables examined. We used fish landing data from West Nusa Tenggara recorded every month between 2012 and 2017 and analyzed using generalized linear models and generalized additive models. We found a seasonal and annual pattern of tuna abundance affected by SST and chlorophyll-a (chl a) and related to upwelling and El Nino event. These results also suggest that a two-month closure to fishing in August and September in southern Lombok is worth considering by the Government to maximize conservation of stocks due to a high abundance of juveniles emerging during the upwelling months from June to August.

Highlights

Tuna is one of the globally most important fish, caught by fishing vessels of more than 85 countries and contributing 5.7% or 4.8 million t to the global seafood production in the year 2016 [1,2]
A total of 41 different grids were fished during all trips, with Fish aggregating device (FAD) fishing taking place in 23 of these grids (Figure 1b)
We found that the best fitted General Additive Models (GAMs) was: GAM Negative Binomial (NB) Model: catch per unit effort (CPUE)~Year + month + spline + spline + spline (Chl a) + spline (SST)

Summary

Introduction

Tuna is one of the globally most important fish, caught by fishing vessels of more than 85 countries and contributing 5.7% or 4.8 million t to the global seafood production in the year 2016 [1,2]. In 2016, the value of tuna at all landing sites in the world was estimated to be more than US$10 billion annually [2], with approximately an additional US$42.2 billion market value [3]. They provide food, key nutrients, and income to coastal countries and their local communities [4]. The species of tuna caught in Indonesian waters include yellowfin (Thunnus albacares), bigeye (Thunnus obesus), albacore (Thunnus alalunga), and skipjack (Katsuwonus pelamis)

Methods

Results

Conclusion