Assessment of the swordfish (Xiphias gladius) population in the ocean
Keywords:
landings, swordfish, Xiphias gladius, carrying capacity, maximum sustainable yield, EPOAbstract
The swordfish (*Xiphias gladius*) fishery is of great socioeconomic importance in the Eastern Pacific Ocean (EPO). However, excessive effort can exceed Maximum Sustainable Yield (MSY) limits, leading to overexploitation and negative impacts on the population. This study analyzes swordfish (*X. gladius*) catch data to derive reference indicators such as carrying capacity, maximum sustainable yield, and population status. Based on landing reports from eight countries, the average catch in the EPO between 1950 and 2020 was 3,162 t, with a median of 2,030 t. Values between the 15th and 85th percentiles ranged from 115 to 7,708 t, and the maximum recorded catch was 15,409 t in 2018. Annual catches relative to the maximum catch indicate that the fishery experienced overfishing during the 2019–2020 period. Catches in the EPO, based on the sum of probabilities, lie around the 50% central tendency, at approximately 12,500 t. Using surplus production models and considering the feasibility of fitting catch data alone, the 1979–2020 period was analyzed, yielding an average catch of 5,204 t, with a range of 299 to 15,049 t. An approximation suggests an MSY between 15,268 and 15,770 t. According to the Kobe plot, the last three years of the time series show levels of overfishing (F > FMRS), and only in 2019 did the fishery exhibit conditions indicating stock overfishing (B < BMRS), with biomass values slightly below BMRS. In 2020, biomass levels were similar to those observed at the beginning of the analyzed time series. This result remains consistent when considering catch levels falling between the 15th and 85th percentiles.
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