Developing an Abundance Index of Skipjack Tuna (Katsuwonus pelamis) from a Coastal Drifting Gillnet Fishery in the Southern Waters of Indonesia

Autor: Dian Novianto, Ilham, Chandara Nainggolan, Syarif Syamsuddin, Arief Efendi, Sugianto Halim, Yaser Krisnafi, Muhamad Handri, Abdul Basith, Yusrizal, Erick Nugraha, Suciadi Catur Nugroho, Bram Setyadji
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Fishes, Vol 4, Iss 1, Pp 10-0 (2019)
Druh dokumentu: article
ISSN: 2410-3888
DOI: 10.3390/fishes4010010
Popis: Skipjack tuna is targeted by various types of fishing gear in coastal countries. Due to its resilience, it has withstood heavy fishing pressure in the past few decades. Coastal drifting gillnet fleets also mark skipjack as their main target, but it is often overlooked in terms of stock assessment. This study provides new information on an abundance index based on fishery-dependent data from 2010 to 2017. Generalized linear models (GLMs) were used to standardize the catch-per-unit-of-effort (CPUE) using year, quarter, and gross tonnage as the prediction variables. Model goodness-of-fit and model selection were based on the Akaike Information Criterion (AIC), the pseudo coefficient of determination (R2), and model diagnostics with a residual analysis. The final estimation of the abundance index was calculated by least square means or marginal means. The results showed that the index was heavily influenced by the year and quarter, but it did not relate to the vessel’s capacity. While the CPUE series fluctuated greatly, it showed a declining trend over the years of observation.
Databáze: Directory of Open Access Journals