Morphologic Study Of Common Ichthyoplankton In The Haizhou Bay During Spring And Summer

Early life history of fishes can be divided into three phases, eggs, larva and juvenile. The eggs and planktonic stages of marine fish are more sensitivity to the marine environmental factors. Survival and abundance of fishes during early life history stages has long been recognized as a probable source of variability in recruitment to adult stocks, and its sustainable utilization. The correct taxonomic identification of the ichthyoplankton is the basis in marine ecosystem research and it was the prerequisite for quantitative fisheries stock assessment. At present, the identification methods of ichthyoplankton including traditional morphological method, molecular method, scanning electronic observation on the egg envelope, monocline antibodies, and computer image analysis technology. For practical reasons, most identification offish eggs still uses traditional light microscopy. The morphological characteristics for identification of fish eggs including the shape of fish eggs, egg envelope structure, perivitelline space, yolk structure, oil globule, egg size, embryo and pigment et.al. The morphological characteristics for identification of larva and juvenile including the shape of fish, position of the anus, digestive system, number of myomere, size and distribution of pigment, size and distribution of fin. A number of monographs for identification of the ichthyoplankton from a piece of sea area has been published. In china, the morphological description for early life history stages of fish is mostly under artificial cultivation in the laboratory, monographs for identification of the ichthyoplankton from a piece of sea area are very rare.Haizhou Bay fishing grounds as one of the important spawning grounds in the coastal of Yellow Sea, the species and quantitative distribution of ichthyoplankton in this area show a very important role for supplemental resources in the Yellow Sea. In recent years, the fishes resources of Haizhou Bay are in a state of increasing weakness. Surveys were conducted in six voyages during spring and summer in 2013 in Haizhou Bay, to determine the ichthyoplankton composition, abundance and assemblage characteristics. Based on the spawning surveys in 2013, morphological description of common ichthyoplankton in the Haizhou Bay during spring and summer shows in this paper. The main findings are as follows:(1) Comprehensive the survey data of six voyages, we chose the 23 species offish eggs which common in the Haizhou Bay. The different developmental stages of each species take pictures under an optical microscope. The morphological description of fish eggs is combination of on our observation and historical research. Egg shape, egg-diameter, oil globule diameter, structure of egg membrane, structure of york and pigment distribution were deseirpted in detal. Record the distribution of egg-diameter of 23 species of fish egg. The results diameter’change with spawning season progressed in 19 sprcies of fish egg showed that the mean diameter of fish egg gradually decreased with spawning season progressed except Mugil so-iuy and Larimichthys polyactis. The mechanism of the mean diameter of Mugil so-iuy and Larimichthys polyactis gradually increased with spawning season progressed have yet to be further studied. Compared with historical research, we found the eggs size shows a different with historical data in some species, the causes have yet to be further studied(2) Comprehensive the survey data of six voyages, we chose the 17 species of larvae and juvenile which common in the Haizhou Bay. The morphological description of larvae and juvenile is combination of on our observation and historical research. Shape of fish, position of the anus, digestive system, number of myomere, size and distribution of pigment and fin were deseirpted in detal(3) The morphology observation of common ichthyoplankton in the Haizhou Bay during spring and summer in this paper can be used as a indentifiation guide of the early life history stages of fishes from Haizhou Bay.