جستجوی مقالات مرتبط با کلیدواژه "صدف" در نشریات گروه "شیلات"

Rocky shores or artificial structures increase the diversity of sessile and mobile fauna. On the Southern shores of the Caspian Sea, these areas have been constructed artificially. The bivalve Mytilaster lineatus is one of the non-native species of the Caspian Sea, which widely distributed in the southern coasts. In this investigation, a certain level of the breakwater walls in in both regions of the Anzali port and the Caspian port were scraped and cleaned off all organisms. The population structure, growth, and abundance of M. lineatus were seasonally investigated in the sampling units. M. lineatus species was not present inside the port area of Anzali region, while it was established in the marina area of the Caspian port but its abundance was gradually decreased. A gradually increase in the abundance and biomass of the bivalves was observed in both marine parts of the mentioned regions. Five months after the beginning of survey, all length classes were observed in the population after five months and the height length of 13 mm present in the specimens. One year after the first sampling, the maximum length was 17.13 mm. The growth rate in summer-autumn was calculated at about 0.075 mm per day. After one year, the biomass was about 2 kg per square meter, which shows that this species is extremely invasive in the southern Caspian regions. The abundance of this species in areas far from the coast can provide the food resources for many species such as sturgeon fish and Kutum, which can be investigated by a pilot program with creating artificial habitats.

Babylonia spirata is one of the important commercial oyster species in the world. The ecological basis of the habitats of this mollusk in the coastal waters and in the areas of the continental plateau is a significant help to fishermen and operators. Therefore, to identify the ecological characteristics of the Babylon Sea snail habitat in the northern waters of the Oman Sea, water sampling was done to determine temperature, pH, salinity, dissolved oxygen, nutrients, turbidity, and sediment, the total organic matter and the type of substrate, Babylon species to determine CPUE was done monthly from September 2021 to May 2022. The results showed that the average water temperature during the study period was 27.79°C in Konarak, 26.99 in Pezam, and 28.5 in Pasabandar and Bris. The average salinity in Kanarak, Pozem, Bris, and Pasbandar stations were 39.33, 26.99, 39.25, and 39.25 g/L, turbidity 5.48, 2.5, 7.25 and 7.25 FTU, acidity 8.25, 8.22, 8.18 and 8.18, DO 6.6, 7.06, 6.97 and 6.97 mg/l, nitrate 1.35, 1.16, 1.11 and 1.11 mg/l, nitrite 0.04, 0.02, 0.055 and 0.055 mg/l, ammonia 0.05, 0.19, 0.01 and 0.01 mg/liter,  phosphate 0.37, 0.23, 0.25 and 0.25mg/liter, and the organic matter 0.64, 0.52, 1.67 and 1.67%, respectively. The results revealed that nutrients play an important role in the density of Babylon in this region. With the increase of nutrients, the density of Babylon increases with a sharp peak and reached the maximum in October and November, and after that, with the decrease of food, the density decreases. Based on multiple linear regression analysis, the nitrite was highly related to the amount of catch per unit effort of the Babylon Sea snail.

In order to identify and determine the distribution of economic and ornamental seashells in the northern coasts of the Persian Gulf, sampling was done in upper, middle and bottom intertidal zone in all four seasons and in mud, sand and rocky substrates. Onshore samples were collected through diving and trawling. Identification of specimens was carried out inside the country and confirmed by Institute of Malacology, Tokyo, Japan.381 species belonging to 117 families and 231 genera were identified. There was no significant difference in the warm and cold months in terms of diversity, although the density of the species was much higher in the warm seasons. In terms of species diversity, Bandar-length, Faroor and Hendurabi islands were the most diverse. In terms of size, the largest shells found were Sepia pharaonius and Pinna muricata with a total length of 45 cm and the smallest one with a size of 1 mm was Acteocina involute.