SAINT JOHN HARBOUR MONITORING RECOMMENDATIONS

Sediment contaminants and infaunal invertebrates

• Sample annually in October for sediment invertebrates and contaminants
• Collect 5 or more grab samples per site at the 6 established reference sites
• Divide grab samples for sediment analysis and invertebrate analysis
• Additional 3 years of sampling recommended to solidify baseline information

• Good indicator of habitat quality and pollution exposure for aquatic species
• Some invertebrate species are pollution tolerant and are indicative of sites with more contamination
• Some SJH stakeholders already require this sampling for other projects
• Sediment contaminants have low seasonal and annual variability at reference sites

• Invertebrate results can be variable and affected by sediment quality
• Longer-term sampling of sediment dwelling invertebrates is required to establish a baseline because of their natural variability
• Requires taxonomic expertise and access to specialized analytical equipment for chemical analysis

Caged mussels

• Cage 100 individuals/site for 90 day exposure at 6 sites, February to April
• Measure survival, growth, reproduction, tissue metal concentrations

• Good indicator of water quality conditions
• Well-studied species, data available from broader geographic area (Gulf Watch program) for comparison
• Used in other biomonitoring studies/programs as an alternative to fish

• Finding source of mussels for caging can be difficult
• Cages can be lost due to human interference or weather conditions
• Difficult to distinguish between Atlantic coast mussel species
• Difficult to measure growth and reproduction on the same samples because they have different optimal sampling times

Ichthyoplankton

• Collect 3 samples per site in June (annually)
• 333 μm mesh plankton net with 10-minute tows
• Outer harbour sites better for biomonitoring (more representative of community structure)

• Can be a good indicator of water quality conditions
• Abundant and easily caught
• May be indicative of conditions for mature fish

• Further research is needed to determine whether  ichthyoplankton are a good sentinel in the SJH and whether they warrant inclusion in a long-term monitoring program
• Inclusion of invertebrate organisms in plankton would be more representative of overall ecological conditions
• Requires specialized taxonomic expertise

Fish

• Not recommended for standard monitoring activities

• Economic, cultural, recreational value
• Useful for addressing specific monitoring questions (e.g. impact of dredging)

• Difficult to catch consistent numbers of individuals and species across sites and dates using available equipment

Sand Shrimp

• Sand shrimp are relatively easy to sample onshore with a beach seine net or offshore with a small-mesh bottom trawl
• Optimal sampling time from May to August when egg-bearing females are most common
• May migrate offshore during winter, so further study is needed to understand seasonal movement

• Widely distributed, easy to catch and measure
• Data available from other monitoring studies for comparison
• Results suggest sand shrimp are relatively sedentary from spring to fall
• Preliminary results show potential sensitivity to stressors (e.g. indicators of wastewater input)

• Preliminary findings indicate they are of limited use for assessing dredging impacts
• Further study needed to determine optimal standard monitoring