Research Questions & Method Outline
Question 1: Does the type of adjacent habitat associated with the Posidonia australis seagrass bed influence the fish assemblage within seagrass bed?
Mensurative Experiments
Fish abundance and diversity will be assessed in Posidonia australis beds in areas within 5m of the adjacent habitats of interest at each site in each estuary using a combination of seine netting and underwater video surveys.
Manipulative Field Experiments
Artificial seagrass units (ASUs) mimicking the morphology of Posidonia australis will be deployed within a single estuary adjacent to rocky algal reef, sand, natural Posidonia australis and seagrass of another species. After sufficient time has elapsed for algal fowling and fish recruitment (3 – 4 weeks), a combination of seine netting and underwater video surveying will be employed to collect fish assemblage data.
Question 2: How does the distance from an adjacent habitat influence the fish assemblage within the Posidonia australis bed?
Mensurative Experiments
Fish abundance and diversity will be assessed at predetermined intervals perpendicular to and away from the adjacent habitat into the seagrass bed using a combination of seine netting and underwater video surveys.
Question 3: Does a change in habitat diversity and configuration / spatial arrangement influence the fish assemblage within a given ecosystem with respect to fish abundance and species diversity?
Manipulative Field Experiments
Combinations of habitat diversity conditions and configurations will be constructed and deployed with adequate separation distance between different treatments within a single estuary. After allowing adequate algal fowling of and fish recruitment within the artificial habitats (3 – 4 weeks), each unit, done in replicates, will be sampled for fish diversity and abundance using baited underwater video cameras. Artificial habitats to be constructed include artificial seagrass units and artificial rocky reefs.
Mensurative Experiments
Fish abundance and diversity will be assessed in Posidonia australis beds in areas within 5m of the adjacent habitats of interest at each site in each estuary using a combination of seine netting and underwater video surveys.
Manipulative Field Experiments
Artificial seagrass units (ASUs) mimicking the morphology of Posidonia australis will be deployed within a single estuary adjacent to rocky algal reef, sand, natural Posidonia australis and seagrass of another species. After sufficient time has elapsed for algal fowling and fish recruitment (3 – 4 weeks), a combination of seine netting and underwater video surveying will be employed to collect fish assemblage data.
Question 2: How does the distance from an adjacent habitat influence the fish assemblage within the Posidonia australis bed?
Mensurative Experiments
Fish abundance and diversity will be assessed at predetermined intervals perpendicular to and away from the adjacent habitat into the seagrass bed using a combination of seine netting and underwater video surveys.
Question 3: Does a change in habitat diversity and configuration / spatial arrangement influence the fish assemblage within a given ecosystem with respect to fish abundance and species diversity?
Manipulative Field Experiments
Combinations of habitat diversity conditions and configurations will be constructed and deployed with adequate separation distance between different treatments within a single estuary. After allowing adequate algal fowling of and fish recruitment within the artificial habitats (3 – 4 weeks), each unit, done in replicates, will be sampled for fish diversity and abundance using baited underwater video cameras. Artificial habitats to be constructed include artificial seagrass units and artificial rocky reefs.