Species Composition, Growth, and Trophic Traits of Hairtail (Trichiuridae), the Most Productive Fish in Chinese Marine Fishery

Abstract

Hairtail (Scombriformes: Trichiuridae) have always ranked first in single-species production in Chinese marine fishery. However, due to the confusion of species identification, in official statistics, data on hairtail production and economic value are a combination of all the different species of Trichiuridae. In this study, based on sampling along China's coastal areas, the composition and distribution of common hairtail species, as well as their age, growth, and trophic traits, are discussed. Six species of four genera and two subfamilies were identified, and largehead hairtail (Trichiurus japonicus) and Savalai hairtail (Lepturacanthus savala) were the most important populations that constituted catch production. The growth parameter b could be divided into two groups, with values in species mostly inhabiting northern parts of Chinese seas higher than those in southern parts. Most individuals were 1-2 years of age, suggesting species sexual precocity and individual miniaturization under multiple stresses. Species of Trichiuridae are at the top of the food web and play a bottom-up role in regulating the trophic dynamics of marine food webs. Largehead hairtail showed the highest stability and the greatest impact on the stability of the trophic structure. Despite temporary resource maintenance under fishery-induced evolution, the effective recovery and reasonable utilization of hairtail resources are still the main focuses of attention for Chinese marine fishery.

Keywords: distribution; otolith; stable isotope; taxonomy; trophic level.

Figure A1

Measurements of morphological characteristics of hairtail for species identification. ED: Eye diameter; PreL: Preorbital length; PosL: Postorbital length; HL: Head length; PL: Preanal length; TL: Total length; HD: Head depth; BD: Body depth; IW: Interorbital width; MCL(ab): Mouth crack length; MCW: mouth crack width; ac; ad; bc; bd; be; bf; dc; de; df.

Figure A2

Morphology of otolith of six hairtail species. Note: (a), T. japanicus; (b), T. nanhaiensis; (c), T. brevis; (d), L. savala; (e), E. muticus; (f), Te. Cristatus.

Figure A3

Age determination from otolith of largehead hairtail Trichiurus japonicus. (A), 6 years; (B), 5 years; (C), 4 years; (D), 3 years.

Figure A4

Photos of six species of Trichiuridae in the coastal waters of China.

Figure A5

Hand drawing of six hairtails in the Chinese seas, with details of morphological characteristics for species identification.

Figure 1

Composition and distribution of six species of Trichiuridae in China’s coastal waters. The abbreviation of sampling sites name was the same of Table 1. Different colors represented different species: blue, Trichiurus japonicus; green, T. nanhaiensis; yellow, T. brevis; red, Lepturacanthus savala; purple, Eupleurogrammus muticus; light blue, Tentoriceps cristatus.

Figure 2

Population composition in terms of preanal length and body weight of six species of Trichiuridae in Chinese seas.

Figure 3

Relationship between preanal length and body weight in six species of Trichiuridae in Chinese seas.

Figure 4

Relationship between preanal lengths and otolith radius of largehead hairtail Trichiurus japonicus.

Figure 5

Stable carbon and nitrogen isotopic characteristics of six species of Trichiuridae in Chinese seas. TJ, Trichiurus japonicus; TN, T. nanhaiensis; TB, T. brevis; LS, Lepturacanthus savala; EM, Eupleurogrammus muticus; TC, Tentoriceps cristatus.

Figure 6

Two-dimension map of trophic niches of six species of Trichiuridae in the Chinese seas. TJ, Trichiurus japonicus; TN, T. nanhaiensis; TB, T. brevis; LS, Lepturacanthus savala; EM, Eupleurogrammus muticus; TC, Tentoriceps cristatus.