{"title":"Intraspecific density effect on growth of Marphysa “sp.” Juveniles","authors":"J. Garcês, P. Pousão‐Ferreira","doi":"10.3989/SCIMAR.05078.012","DOIUrl":null,"url":null,"abstract":"There is growing demand for the territorial tube-building genus Marphysa (Eunicidae: Polychaete), commonly known in Portugal as “goose”, for use as fishing bait, and it is being harvested all around the world for that purpose. Effects of intraspecific density on juvenile growth were studied over a four-month period in laboratory facilities. Three polychaete densities (low, 50 worms; medium, 150 worms; and high, 250 worms) were used in a 0.25 m aquarium containing sandy sediment and recirculating water. Total length, dry weight and number of segments were recorded for 60% of the initial population. All polychaetes were also counted to determine mortality rate and territorial behaviour through the existence of body lesions and broken and regenerating posterior segments. The results obtained in this study showed that density had a significant effect (p<0.001) on growth rates in any of the densities studied and that growth was significantly higher at lower densities (p<0.001). For all density levels, estimated daily growth was higher in the first month, decreasing progressively over time. The high aggressiveness and territorial behaviour of Marphysa “sp.” juveniles, well evidenced by the highest mortality (35%) under high density and by the presence of worms with lesions under low density (30%) observed in the first month, suggests that territoriality is probably the main factor involved in the organization and spatial arrangements of individuals within a population. Marphysa juveniles probably compete for burrow space. The results reveal that Marphysa juveniles have a very territorial and aggressive behaviour that should be considered if the species is used for aquaculture production. Additional studies are required to determine the density effects for different developmental stages.","PeriodicalId":21600,"journal":{"name":"Scientia Marina","volume":null,"pages":null},"PeriodicalIF":0.8000,"publicationDate":"2021-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Scientia Marina","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.3989/SCIMAR.05078.012","RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"MARINE & FRESHWATER BIOLOGY","Score":null,"Total":0}
引用次数: 1
Abstract
There is growing demand for the territorial tube-building genus Marphysa (Eunicidae: Polychaete), commonly known in Portugal as “goose”, for use as fishing bait, and it is being harvested all around the world for that purpose. Effects of intraspecific density on juvenile growth were studied over a four-month period in laboratory facilities. Three polychaete densities (low, 50 worms; medium, 150 worms; and high, 250 worms) were used in a 0.25 m aquarium containing sandy sediment and recirculating water. Total length, dry weight and number of segments were recorded for 60% of the initial population. All polychaetes were also counted to determine mortality rate and territorial behaviour through the existence of body lesions and broken and regenerating posterior segments. The results obtained in this study showed that density had a significant effect (p<0.001) on growth rates in any of the densities studied and that growth was significantly higher at lower densities (p<0.001). For all density levels, estimated daily growth was higher in the first month, decreasing progressively over time. The high aggressiveness and territorial behaviour of Marphysa “sp.” juveniles, well evidenced by the highest mortality (35%) under high density and by the presence of worms with lesions under low density (30%) observed in the first month, suggests that territoriality is probably the main factor involved in the organization and spatial arrangements of individuals within a population. Marphysa juveniles probably compete for burrow space. The results reveal that Marphysa juveniles have a very territorial and aggressive behaviour that should be considered if the species is used for aquaculture production. Additional studies are required to determine the density effects for different developmental stages.
期刊介绍:
Scientia Marina is the successor to Investigación Pesquera, a journal of marine sciences published since 1955 by the Institut de Ciències del Mar de Barcelona (CSIC). Scientia Marina is included in the Science Citation Index since 1998 and publishes original papers, reviews and comments concerning research in the following fields: Marine Biology and Ecology, Fisheries and Fisheries Ecology, Systematics, Faunistics and Marine Biogeography, Physical Oceanography, Chemical Oceanography, and Marine Geology. Emphasis is placed on articles of an interdisciplinary nature and of general interest.