While dissolved oxygen levels are always a concern, open coastal spaces allow for more flow between pens, lowering the risk that farmers may create hypoxic conditions by increasing density. But coastal aquaculture faces its own set of challenges. This open environment exposes stock to other risks such as harmful algal blooms (HABs), temperature changes and nutrient deposits from stormwater or freshwater runoff.Safeguard stock health with strategic monitoring

Harmful Algal Blooms

Harmful algal blooms (HABs) continue to increase in frequency and severity as warming waters create ideal conditions for algae growth. Once-seasonal HAB occurrences are on their way to becoming a year-round concern, particularly in tropical climates. At their most extreme, algae overgrowth can create hypoxic conditions, completely consuming DO and leaving aquatic organisms without any oxygen. However, some algae can benefit organisms like oysters, which consume chlorophyll a as a source of food. Precise monitoring of DO helps farmers track algae growth and put contingency plans in place when needed.

Runoff

Freshwater and urban runoff can adversely impact DO levels by introducing excess nutrients into coastal aquaculture environments. Farms located near aquaculture operations can also increase risks for organisms if agricultural runoff enters fresh waterways and travels out to coastal areas. Excess nutrients encourage algae growth and accelerate the consumption of dissolved oxygen, creating effects similar to HABs. Monitoring FDOM serves as a valuable indicator of freshwater runoff and can help identify specific contaminants that may have been carried out to aquaculture farms.

Sediment

In addition to excess nutrients, runoff from storm events can carry sediment and other particulates than can adversely affect aquatic organisms. High sediment concentrations can contribute to suboptimal conditions and turbidity may be accompanied by contaminants or pollutants that can also harm fish and shellfish. It’s important to monitor for turbidity if the operation is located near a coastal outlet for combined sewer overflows (CSOs) or close to dredging or construction activity.

Fluctuating Salinity

Coastal aquaculture operations near freshwater sources experience fluctuating salinity levels that can stress fish or shellfish. Oysters and mussels are typically grown in these brackish environments, where salinity ranges can vary from 5 units to up to 35 units–the salinity level of full seawater. While salinity fluctuations are normal, dramatic changes can stress the animals beyond their capacity. Tracking salinity levels helps aquaculturists make informed decisions about which leases may present the optimal conditions for their shellfish during different seasons.

Cost-effective options for every operation

In an industry like coastal aquaculture, outcomes will always be subject to environmental factors and it can be difficult to impossible to prevent the occasional die-off. Once this occurs, investigating the cause can be challenging, as the trigger factors are often long gone.

But don’t underestimate the difference monitoring can make. With accurate, continuous water quality data, farmers can return to their records and identify the source or cause of changes in water quality. This information is invaluable for understanding natural fluctuations in the environment and strategizing for proactive management of similar conditions in the future. When farmers see patterns start to repeat, they have an advantage in planning a response, cultivating sustainable practices and working toward long-term business security.

Many small operations might view monitoring as a protective measure beyond their budget, but this doesn’t have to be the case. From dissolved oxygen probes to multiparameter instruments, telemetry and beyond, there are equipment options that provide accurate data to support operations at any stage and scale.

The frontline defense for any aquaculture operation is reliable dissolved oxygen measurement. No matter an operation’s scale or location, DO will fluctuate throughout the day and is the most critical parameter for the survival of aquatic life. A compact probe like RDO Blue delivers accurate DO measurements with minimal maintenance.

Though more expensive than membrane-based electrochemical sensors, In-Situ’s optical Rugged Dissolved Oxygen technology offers benefits that make RDO Blue more cost effective in the long run:

• Superior abrasion-resistance technology protects the sensor in harsh conditions and extends the lifespan of the sensor cap.
• Calibration is contained within the cap for easy, error-free setup and recalibration.
• Optical sensors are perfect for coastal environments where water levels are subject to tides, waves or wakes.
• And because they don’t require hydration conditioning and read accurately within 90 seconds of going from dry to wet conditions, they’re ideal for coastal environments, where water levels are constantly changing.

For larger operations, collecting data on multiple parameters provides a full picture of water quality. Aqua TROLL multiparameter instruments come in five-port or seven-port platforms with capacity for four or six water quality sensors and an antifouling wiper. Instruments like this allow aquaculturists to collect data on essential parameters like DO, temperature, pH and conductivity, or expand their monitoring capabilities to include chlorophyll a, FDOM and nutrient ISE sensors.

When considering the ideal setup for an operation, it’s important to think about growth potential and flexibility. All In-Situ Aqua TROLL sensors are interchangeable, so farmers can swap out sensors depending on their needs. Additionally, all In-Situ instruments can support both spot checking and continuous data collection, providing essential flexibility to adapt to growing operations. When connected to a Wireless TROLL Com, In-Situ’s RDO Blue and Aqua TROLL multiparameter sondes allow operators to take spot check readings with the VuSitu mobile app. For smaller operations, this is an excellent way to maximize data collection with a single instrument, gathering instant readings at several key points across the operation.

And for those ready to invest in continuous data collection, these same instruments can connect to VuLink telemetry for easy data transmission. With a powerful software platform like HydroVu to store, graph and analyze the data, farmers can watch multiple water quality parameters evolve in real time. And in the event of a dramatic change in water quality, they can return to records of the critical parameters that might have influenced or precipitated the change.

For large operations, the Rugged Buoy offers an ideal platform to deploy multiparameter instruments and telemetry in or alongside open pens, providing an accurate picture of water quality without the need for a fixed installation. The Rugged Buoy will protect equipment by righting itself after waves or swells and its adjustable well can be extended to monitor at different depths. Several buoys installed strategically across an operation provide full coverage of water quality parameters to give farmers a complete picture of their aquaculture habitat.

Fine-tune operations for sustainable success

The consequences of raising aquatic organisms without monitoring their water quality can substantially impact an operation’s yield, sustainability and viability. But the advantages of meticulous monitoring extend beyond crisis prevention. Collecting data on multiple parameters in coastal aquaculture environments helps farmers build an understanding of the comprehensive needs of their stock and allows them to respond more precisely to these requirements. Access to reliable data not only enables farmers to make informed decisions to support livestock health, but can also enhance business strategy around energy consumption, feeding schedules and other variables. Watching parameters change over time gives farmers a better chance of predicting seasonal fluctuations and responding to runoff and other critical events. Ultimately, collecting accurate data–whether that’s tracking DO as it changes throughout the day or recording an isolated drop in water quality–eliminates the uncertainty that hampers strategic decision making. The ability to look at how water quality is changing minute to minute, day to day, month to month opens the door to understanding why these changes occur and how to optimize the care of aquatic livestock to cut costs, increase yield and create the best conditions for fish to thrive.
Learn more about our reliable and cost-effect monitoring solutions here.