Comparisons of habitat suitability index models of skipjack tuna in the Western and Central Pacific Ocean

Abstract:

Skipjack tuna (Katsuwonus pelamis) is one of the tuna species in the tropical Pacific waters, and is one of the main fishing targets by Chinese tuna purse seine fleets. In this paper, according to the fishing data during 1995 to 2012 in the Western and Central Pacific Ocean waters (5°N-10°S and 125°E-135°W), combined with the remote sensing data of sea surface temperature (SST) and sea surface height (SSH), the frequency distribution method is used to analyze the suitable environmental range (SST and SSH) for skipjack tuna in the Western and Central Pacific Ocean. And the envelope method is also used to establish the suitability index (SI) based on SST and SSH in each quarter. The habitat suitability index (HSI) model is established to calculate the habitat suitability index by using the method of arithmetic average (AMM) and the geometric average method (GMM), and the catch data in 2013 is used to verify. The results show that the skipjack tuna is distributed in the waters with SST ranging from 28 ℃ to 30.5 ℃ and SSH ranging from 65 cm to 95 cm. In terms of fishing effort (fishing days) used as SI, the external envelope method of SI with SST and SSH is the most suitable. For establishing arithmetic average method of skipjack tuna, the suitable weights of SST in each quarter were 0.7, 0.6, 0.3 and 0.6 in the Western and Central Pacific Ocean. It is concluded that the environmental factors in different seasons have different effects on skipjack tuna distribution in the Western and Central Pacific Ocean.